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Scheyer TM. The pseudosuchian record in paleohistology: A small review. Anat Rec (Hoboken) 2024. [PMID: 38655735 DOI: 10.1002/ar.25455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 03/25/2024] [Accepted: 03/30/2024] [Indexed: 04/26/2024]
Abstract
Archosauria originated around the Earth's largest biotic crisis that severely affected all ecosystems globally, the Permotriassic Mass extinction event, and comprises two crown-group lineages: the bird-lineage and the crocodylian lineage. The bird lineage includes the iconic pterosaurs, as well as dinosaurs and birds, whereas the crocodylian lineage includes clades such as aetosaurs, poposaurs, "rauisuchians," as well as Crocodylomorpha; the latter being represented today only by less than 30 extant species of Crocodylia. Despite playing important roles during Mesozoic and Cenozoic ecosystems, both on land and in water, Pseudosuchia received far less attention compared to the bird-lineage, which is also reflected in number and scope of histological studies so far. Lately, the field has seen a shift of focus toward pseudosuchians, however, and the symposium on "Paleohistological Inferences of Paleobiological Traits in Pseudosuchia" held during the International Congress of Vertebrate Morphology 2023 in Cairns, Queensland, Australia, is the latest proof of that. To put these novel aspects of paleohistological and paleobiological research into context, an overview of the non-extant pseudosuchian taxa whose postcranial bones were studied so far is provided here (c. 80 species out of a total of more than 700 extinct species described) and recent trends in pseudosuchian osteohistology are highlighted. In addition, histological studies on cranial and dental material and other potential hard tissues, such as eggshells and otoliths, are briefly reviewed as well.
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Affiliation(s)
- Torsten M Scheyer
- Department of Paleontology, University of Zurich, Zurich, Switzerland
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2
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Scheyer TM, Johnson MM, Bastiaans D, Miedema F, Maxwell EE, Klug C. Oldest record of Machimosaurini (Thalattosuchia, Teleosauroidea): teeth and scavenging traces from the Middle Jurassic (Bajocian) of Switzerland. R Soc Open Sci 2024; 11:240071. [PMID: 38601027 PMCID: PMC11004672 DOI: 10.1098/rsos.240071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Accepted: 03/01/2024] [Indexed: 04/12/2024]
Abstract
The Jurassic period was a time of major diversification for Mesozoic marine reptiles, including Ichthyosauria, Plesiosauria and thalattosuchian Crocodylomorpha. The latter originated in the Early Jurassic and thrived during the Late Jurassic. Unfortunately, the Middle Jurassic, a crucial time in their evolution, has a poor fossil record. Here, we document the first evidence of macrophagous/durophagous Machimosaurini-tribe teleosauroid thalattosuchians from the late Bajocian (ca 169 Ma) in the form of three robust tooth crowns with conical blunt shapes and anastomosed pattern of thick enamel ridges towards the apex, associated with the skeleton of a large ichthyosaur lacking preserved tooth crowns. The tooth crowns were found on the posterior section of the lower jaw (left angular), a lacrimal and the axis neural arch of the ichthyosaur. In addition, some of the distal sections of the posterior dorsal ribs of the ichthyosaur skeleton exhibit rounded bite marks and some elongated furrows that fit in size and shape with the Machimosaurini teeth. These marks, together with the absence of healing in the rib bone are interpreted here as the indicators of peri- to post-mortem scavenging by a Machimosaurini teleosauroid after the large ichthyosaur carcass settled on the floor of a shallow ocean.
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Affiliation(s)
| | | | - Dylan Bastiaans
- Paläontologisches Institut, Universität Zürich, Zürich8006, Switzerland
| | - Feiko Miedema
- Staatliches Museum für Naturkunde Stuttgart, Stuttgart70191, Germany
- Naturkundemuseum Bamberg, Bamberg96047, Germany
| | - Erin E. Maxwell
- Staatliches Museum für Naturkunde Stuttgart, Stuttgart70191, Germany
| | - Christian Klug
- Paläontologisches Institut, Universität Zürich, Zürich8006, Switzerland
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3
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Miedema F, Bastiaans D, Scheyer TM, Klug C, Maxwell EE. A large new Middle Jurassic ichthyosaur shows the importance of body size evolution in the origin of the Ophthalmosauria. BMC Ecol Evol 2024; 24:34. [PMID: 38493100 PMCID: PMC10944604 DOI: 10.1186/s12862-024-02208-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 01/29/2024] [Indexed: 03/18/2024] Open
Abstract
The Middle Jurassic is an important time period for the evolutionary history of marine reptiles as it represented a transitional phase for many clades. Notably, in ichthyosaurs, many early parvipelvian taxa went extinct. The Middle Jurassic saw the emergence of the derived Ophthalmosauria, ultimately becoming the dominant ichthyosaurian clade by the end of the epoch. Even though this is an important period in the evolutionary history of Ophthalmosauria, our understanding remains limited in terms of morphology and taxonomy due to the scarcity of vertebrate-bearing strata. Here we present a large new ichthyosaur from the Bajocian of Switzerland, represented by an almost complete skull with 3D-preserved bones, the (inter)clavicles and a large portion of the postcranial skeleton. After CT- and surface scanning, we reconstructed the 3D in vivo morphology. Our morphological observations and phylogenetic analyses show that the new taxon named Argovisaurus martafernandezi is nested at the base of the Ophthalmosauria. The holotype and only known specimen of Argovisaurus likely represents an adult individual. Bajocian members of the Ophthalmosauria (Mollesaurus and Argovisaurus) were large-bodied animals, a trait typically associated with the more derived Platypterygiinae. This hints at the importance of a large body size early in ophthalmosaurian evolution.LSID: urn:lsid:zoobank.org:act:C3312628-1544-4B87-BBE3-B12346A30BE3LSID: urn:lsid:zoobank.org:act:23C2BD71-8CF0-4D99-848A-0D631518415B.
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Affiliation(s)
- Feiko Miedema
- Staatliches Museum für Naturkunde Stuttgart, Rosenstein 1, Stuttgart, 70191, Germany.
- Universität Zürich, Paläontologisches Institut, Karl Schmid-Strasse 4, Zürich, 8006, Switzerland.
| | - Dylan Bastiaans
- Universität Zürich, Paläontologisches Institut, Karl Schmid-Strasse 4, Zürich, 8006, Switzerland
- NHMB: Naturhistorisches Museum Basel, Augustinergasse 2, Basel, 4001, Switzerland
| | - Torsten M Scheyer
- Universität Zürich, Paläontologisches Institut, Karl Schmid-Strasse 4, Zürich, 8006, Switzerland
| | - Christian Klug
- Universität Zürich, Paläontologisches Institut, Karl Schmid-Strasse 4, Zürich, 8006, Switzerland
| | - Erin E Maxwell
- Staatliches Museum für Naturkunde Stuttgart, Rosenstein 1, Stuttgart, 70191, Germany
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Klug C, Spiekman SNF, Bastiaans D, Scheffold B, Scheyer TM. The marine conservation deposits of Monte San Giorgio (Switzerland, Italy): the prototype of Triassic black shale Lagerstätten. Swiss J Palaeontol 2024; 143:11. [PMID: 38450287 PMCID: PMC10912274 DOI: 10.1186/s13358-024-00308-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 01/23/2024] [Indexed: 03/08/2024]
Abstract
Marine conservation deposits ('Konservat-Lagerstätten') are characterized by their mode of fossil preservation, faunal composition and sedimentary facies. Here, we review these characteristics with respect to the famous conservation deposit of the Besano Formation (formerly Grenzbitumenzone; including the Anisian-Ladinian boundary), and the successively younger fossil-bearing units Cava inferiore, Cava superiore, Cassina beds and the Kalkschieferzone of Monte San Giorgio (Switzerland and Italy). We compare these units to a selection of important black shale-type Lagerstätten of the global Phanerozoic plus the Ediacaran in order to detect commonalities in their facies, genesis, and fossil content using principal component and hierarchical cluster analyses. Further, we put the Monte San Giorgio type Fossillagerstätten into the context of other comparable Triassic deposits worldwide based on their fossil content. The results of the principal component and cluster analyses allow a subdivision of the 45 analysed Lagerstätten into four groups, for which we suggest the use of the corresponding pioneering localities: Burgess type for the early Palaeozoic black shales, Monte San Giorgio type for the Triassic black shales, Holzmaden type for the pyrite-rich black shales and Solnhofen type for platy limestones.
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Affiliation(s)
- Christian Klug
- Universität Zürich, Paläontologisches Institut, Karl-Schmid-Strasse 4, 8006 Zurich, Switzerland
| | | | - Dylan Bastiaans
- Universität Zürich, Paläontologisches Institut, Karl-Schmid-Strasse 4, 8006 Zurich, Switzerland
| | - Beat Scheffold
- Universität Zürich, Paläontologisches Institut, Karl-Schmid-Strasse 4, 8006 Zurich, Switzerland
| | - Torsten M. Scheyer
- Universität Zürich, Paläontologisches Institut, Karl-Schmid-Strasse 4, 8006 Zurich, Switzerland
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Gere K, Nagy AL, Scheyer TM, Werneburg I, Ősi A. Complex dental wear analysis reveals dietary shift in Triassic placodonts (Sauropsida, Sauropterygia). Swiss J Palaeontol 2024; 143:4. [PMID: 38328031 PMCID: PMC10844150 DOI: 10.1186/s13358-024-00304-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 01/05/2024] [Indexed: 02/09/2024]
Abstract
Placodonts were durophagous reptiles of the Triassic seas with robust skulls, jaws, and enlarged, flat, pebble-like teeth. During their evolution, they underwent gradual craniodental changes from the Early Anisian to the Rhaetian, such as a reduction in the number of teeth, an increase in the size of the posterior palatal teeth, an elongation of the premaxilla/rostrum, and a widening of the temporal region. These changes are presumably related to changes in dietary habits, which, we hypothesise, are due to changes in the type and quality of food they consumed. In the present study, the dental wear pattern of a total of nine European Middle to Late Triassic placodont species were investigated using 2D and 3D microwear analyses to demonstrate whether there could have been a dietary shift or grouping among the different species and, whether the possible changes could be correlated with environmental changes affecting their habitats. The 3D analysis shows overlap between species with high variance between values and there is no distinct separation. The 2D analysis has distinguished two main groups. The first is characterised by low number of wear features and high percentage of large pits. The other group have a high feature number, but low percentage of small pits. The 2D analysis showed a correlation between the wear data and the size of the enlarged posterior crushing teeth. Teeth with larger sizes showed less wear feature (with higher pit ratio) but larger individual features. In contrast, the dental wear facet of smaller crushing teeth shows more but smaller wear features (with higher scratch number). This observation may be related to the size of the food consumed, i.e., the wider the crown, the larger food it could crush, producing larger features. Comparison with marine mammals suggests that the dietary preference of Placochelys, Psephoderma and Paraplacodus was not exclusively hard, thick-shelled food. They may have had a more mixed diet, similar to that of modern sea otters. The diet of Henodus may have included plant food, similar to the modern herbivore marine mammals and lizards. Supplementary Information The online version contains supplementary material available at 10.1186/s13358-024-00304-x.
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Affiliation(s)
- Kinga Gere
- Institute of Geography and Earth Sciences, Department of Paleontology, ELTE Eötvös Loránd University, Pázmány Péter Sétány 1/C, 1117 Budapest, Hungary
| | - András Lajos Nagy
- Department of Propulsion Technology, Széchenyi István University, Egyetem Tér 1, 9026 Győr, Hungary
| | - Torsten M. Scheyer
- Universität Zürich, Paläontologisches Institut, Karl Schmid-Strasse 4, CH-8006 Zurich, Switzerland
| | - Ingmar Werneburg
- Senckenberg Centre for Human Evolution and Palaeoenvironment, Universität Tübingen, Sigwartstraße 10, 72076 Tübingen, Germany
- Fachbereich Geowissenschaften an der Eberhard Karls Universität Tübingen, 72074 Tübingen, Germany
| | - Attila Ősi
- Institute of Geography and Earth Sciences, Department of Paleontology, ELTE Eötvös Loránd University, Pázmány Péter Sétány 1/C, 1117 Budapest, Hungary
- Hungarian Natural History Museum, Ludovika Tér 2, 1083 Budapest, Hungary
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Ponce DA, Scheyer TM, Cerda IA, Desojo JB. Palaeobiological inferences of "rauisuchians" Fasolasuchus tenax (Los Colorados Fm., Argentina) and Prestosuchus chiniquensis (Santa Maria Super sequence, Brazil) from the Middle-Upper Triassic of South America based on microstructural analyses. J Anat 2023; 243:893-909. [PMID: 37519277 PMCID: PMC10641045 DOI: 10.1111/joa.13937] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 07/12/2023] [Accepted: 07/13/2023] [Indexed: 08/01/2023] Open
Abstract
"Rauisuchia" is a non-monophyletic group of quadrupedal and carnivorous pseudosuchians that inhabited the entire world during the Middle-Upper Triassic period (Anisian/Ladinian-Rhaetian). In South America, "rauisuchians" reached the largest sizes among continental carnivores. Despite their important ecological role, some aspects of their palaeobiology have been poorly examined. Here, we study appendicular bones, dorsal ribs and osteoderms of two genera, the Argentinean Fasolasuchus tenax (PVL 3850, holotype) and the Brazilian Prestosuchus chiniquensis (SNSB-BSPG AS XXV) respectively. The femur of F. tenax is formed by laminar fibrolamellar bone, which is composed of non-fully monorefringent woven-fibred matrix and primary osteons; the dorsal rib has a Haversian bone composition with an external fundamental system recorded and the osteoderm is formed by well-organised parallel-fibred bone. The femur, humerus and fibula of P. chiniquensis are mostly composed of strongly arranged parallel-fibred bone and a laminar vascularisation. The minimal ages obtained correspond to 9 years for F. tenax (based on the maximum number of growth marks in the osteoderm) and 4 years for P. chiniquensis (obtained from the highest count of growth marks in the femur and in the humerus). F. tenax attained somatic and skeletal maturity, while P. chiniquensis was near to reaching skeletal and sexual maturity, but it was somatically immature. The overall rapid growth rate and the high and uniform vascularisation seems to imply that these features are common in most of "rauisuchians", except in P. chiniquensis.
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Affiliation(s)
- Denis A Ponce
- Instituto de Investigación en Paleobiología y Geología (IIPG), CONICET-Universidad Nacional de Río Negro, General Roca, Argentina
- Museo Provincial 'Carlos Ameghino', Cipolletti, Argentina
| | | | - Ignacio A Cerda
- Instituto de Investigación en Paleobiología y Geología (IIPG), CONICET-Universidad Nacional de Río Negro, General Roca, Argentina
| | - Julia B Desojo
- CONICET-División Paleontología Vertebrados, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, Buenos Aires, Argentina
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Bastiaans D, Buffa V, Scheyer TM. To glide or to swim? A reinvestigation of the enigmatic Wapitisaurus problematicus (Reptilia) from the Early Triassic of British Columbia, Canada. R Soc Open Sci 2023; 10:231171. [PMID: 38026014 PMCID: PMC10646446 DOI: 10.1098/rsos.231171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 10/20/2023] [Indexed: 12/01/2023]
Abstract
Wapitisaurus problematicus was initially described as a member of the Weigeltisauridae, a clade of Late Permian gliding reptiles from Eurasia and Madagascar. However, the poor preservation of the holotype and only known specimen, from the lower Sulphur Mountain Formation at Ganoid Ridge (British Columbia, Canada), raised doubts about this assignment. Here, we redescribe W. problematicus and reassess its systematic position among diapsid reptiles. Comparison with all known weigeltisaurids, as well as contemporaneous reptiles from the Sulphur Mountain Formation, indicates that the taxon instead represents a thalattosauroid thalattosauriform, with noted similarities to Thalattosaurus and Paralonectes. This reidentification restricts weigeltisaurids to the Late Permian, with no occurrence in North America. Wapitisaurus problematicus potentially represents one of the oldest thalattosauriforms and increases our understanding of their diversity and disparity during the late Early and Middle Triassic. The close morphological similarities with later (thalattosauroid) thalattosauriforms and their high abundance in (shallow) marine settings may indicate an earlier invasion of this realm than previously assumed. This parallels observations in early ichthyopterygians with widespread opportunistic trophic niche diversification occurring relatively rapidly after the end-Permian mass extinction event.
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Affiliation(s)
- Dylan Bastiaans
- Palaeontological Institute and Museum, University of Zurich, Zurich 8006, Switzerland
| | - Valentin Buffa
- Evolutionary Studies Institute, University of the Witwatersrand, Private Bag 3, Johannesburg, Gauteng WITS 2050, South Africa
- Muséum National d'Histoire Naturelle, Centre de Recherche en Paléontologie – Paris, UMR 7207 CNRS-MNHN-SU, CP38, 8 Rue Buffon, Paris, Île-de-France 75005, France
| | - Torsten M. Scheyer
- Palaeontological Institute and Museum, University of Zurich, Zurich 8006, Switzerland
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Miedema F, Bindellini G, Dal Sasso C, Scheyer TM, Maxwell EE. Ontogenetic variation in the cranium of Mixosaurus cornalianus, with implications for the evolution of ichthyosaurian cranial development. Swiss J Palaeontol 2023; 142:27. [PMID: 37810205 PMCID: PMC10556136 DOI: 10.1186/s13358-023-00289-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 08/27/2023] [Indexed: 10/10/2023]
Abstract
Relatively complete ontogenetic series are comparatively rare in the vertebrate fossil record. This can create biases in our understanding of morphology and evolution, since immaturity can represent a source of unrecognized intraspecific variation in both skeletal anatomy and ecology. In the extinct marine reptile clade Ichthyopterygia, ontogenetic series were widely studied only in some Jurassic genera, while the ontogeny of the oldest and most basal members of the clade is very poorly understood. Here, we investigate cranial ontogeny in Mixosaurus cornalianus, from the Middle Triassic Besano Formation of the Swiss and Italian Alps. This small-bodied taxon is represented by a wealth of material from multiple size classes, including fetal material. This allows us to assess ontogenetic changes in cranial morphology, and identify stages in the ontogenetic trajectory where divergence with more derived ichthyosaurs has occurred. Early ontogenetic stages of Mixosaurus show developmental patterns that are reminiscent of the presumed ancestral (early diverging sauropsid) condition. This is prominently visible in the late fetal stage in both the basioccipital, which shows morphology akin to basal tubera, and in the postorbital, which has a triradiate head. The ontogenetic trajectory of at least some of the cranial elements of Mixosaurus is therefore likely still very akin to the ancestral condition, even though the adult cranium diverges from the standard diapsid morphology. Supplementary Information The online version contains supplementary material available at 10.1186/s13358-023-00289-z.
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Affiliation(s)
- Feiko Miedema
- Staatliches Museum für Naturkunde Stuttgart, Rosenstein 1, 70191 Stuttgart, Germany
- Hohenheim University, Schloss Hohenheim 1A, 70599 Stuttgart, Germany
| | - Gabriele Bindellini
- Dipartimento di Scienze della Terra, Università degli Studi di Milano, Milan, Italy
- Dipartimento di Scienze della Terra, Sapienza Università di Roma, Rome, Italy
| | | | - Torsten M. Scheyer
- Universität Zürich, Paläontologisches Institut, Karl Schmid-Strasse 4, 8006 Zürich, Switzerland
| | - Erin E. Maxwell
- Staatliches Museum für Naturkunde Stuttgart, Rosenstein 1, 70191 Stuttgart, Germany
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Laboury A, Scheyer TM, Klein N, Stubbs TL, Fischer V. High phenotypic plasticity at the dawn of the eosauropterygian radiation. PeerJ 2023; 11:e15776. [PMID: 37671356 PMCID: PMC10476616 DOI: 10.7717/peerj.15776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 06/29/2023] [Indexed: 09/07/2023] Open
Abstract
The initial radiation of Eosauropterygia during the Triassic biotic recovery represents a key event in the dominance of reptiles secondarily adapted to marine environments. Recent studies on Mesozoic marine reptile disparity highlighted that eosauropterygians had their greatest morphological diversity during the Middle Triassic, with the co-occurrence of Pachypleurosauroidea, Nothosauroidea and Pistosauroidea, mostly along the margins of the Tethys Ocean. However, these previous studies quantitatively analysed the disparity of Eosauropterygia as a whole without focussing on Triassic taxa, thus limiting our understanding of their diversification and morphospace occupation during the Middle Triassic. Our multivariate morphometric analyses highlight a clearly distinct colonization of the ecomorphospace by the three clades, with no evidence of whole-body convergent evolution with the exception of the peculiar pistosauroid Wangosaurus brevirostris, which appears phenotypically much more similar to nothosauroids. This global pattern is mostly driven by craniodental differences and inferred feeding specializations. We also reveal noticeable regional differences among nothosauroids and pachypleurosauroids of which the latter likely experienced a remarkable diversification in the eastern Tethys during the Pelsonian. Our results demonstrate that the high phenotypic plasticity characterizing the evolution of the pelagic plesiosaurians was already present in their Triassic ancestors, casting eosauropterygians as particularly adaptable animals.
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Affiliation(s)
- Antoine Laboury
- Evolution & Diversity Dynamics Lab, Université de Liège, Liège, Belgium
| | | | - Nicole Klein
- Institute of Geosciences, Paleontology, University of Bonn, Bonn, Germany
| | - Thomas L. Stubbs
- School of Life, Health & Chemical Sciences, Open University, Milton Keynes, United Kingdom
| | - Valentin Fischer
- Evolution & Diversity Dynamics Lab, Université de Liège, Liège, Belgium
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Scheyer TM, Oliveira GR, Romano PSR, Bastiaans D, Falco L, Ferreira GS, Rabi M. A forged 'chimera' including the second specimen of the protostegid sea turtle Santanachelysgaffneyi and shell parts of the pleurodire Araripemys from the Lower Cretaceous Santana Group of Brazil. Swiss J Palaeontol 2023; 142:6. [PMID: 37163143 PMCID: PMC10163108 DOI: 10.1186/s13358-023-00271-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 03/29/2023] [Indexed: 05/11/2023]
Abstract
Fossils of Cretaceous sea turtles adapted to an open marine lifestyle remain rare finds to date. Furthermore, the relationships between extant sea turtles, chelonioids, and other Mesozoic marine turtles are still contested, with one key species being Santanachelys gaffneyi Hirayama, 1998, long considered the earliest true sea turtle. The species is an Early Cretaceous member of Protostegidae, a controversial clade either placed within or closely related to Chelonioidea or, alternatively, along the stem lineage of hidden-neck turtles (Cryptodira) and representing an independent open marine radiation. Santanachelys gaffneyi is one of the most completely preserved early protostegids and is therefore critical for establishing the global phylogenetic position of the group. However, the single known specimen of this taxon is yet to be described in detail. Here we describe a second specimen of Santanachelys gaffneyi from its type horizon, the Romualdo Formation (late Aptian) of the Santana Group of the Araripe basin, NE Brazil. The skeletal elements preserved include the posterior part of the skull, neck vertebrae, shoulder girdle, anterior-most and left/central part of the carapace with few peripherals, and plastron lacking most of the hyoplastra. The remaining part of the carapace was apparently completed by fossil dealers using an anterior part of the pleurodiran Araripemydidae, tentatively identified as a shell portion of cf. Araripemys barretoi, a more common Santana fossil turtle, among other indeterminate turtle shell fragments. The purpose of this paper is to report the repatriation of the specimen to Brazil and to provide a preliminary description. Supplementary Information The online version contains supplementary material available at 10.1186/s13358-023-00271-9.
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Affiliation(s)
- Torsten M Scheyer
- Department of Palaeontology, University of Zurich, Karl Schmid-Strasse 4, 8006 Zurich, Switzerland
| | - Gustavo R Oliveira
- Departamento de Biologia, Área de Ecologia, Laboratório de Paleontologia & Sistematica, Universidade Federal Rural de Pernambuco, Rua Dom Manuel de Medeiros S/No., Dois Irmãos, Recife, Pernambuco 52171-900 Brazil
| | - Pedro S R Romano
- Departamento de Biologia Animal, Universidade Federal de Viçosa, Viçosa, Minas Gerais Brazil
| | - Dylan Bastiaans
- Department of Palaeontology, University of Zurich, Karl Schmid-Strasse 4, 8006 Zurich, Switzerland
| | - Lisa Falco
- SCANCO Medical AG, Fabrikweg 2, 8306 Brüttisellen, Switzerland
| | - Gabriel S Ferreira
- Senckenberg Centre for Human Evolution and Palaeoenvironment (HEP), Sigwartstrasse 10, 72076 Tübingen, Germany
- Department of Geosciences, University of Tübingen, Hölderlinstrasse 12, 72074 Tübingen, Germany
| | - Márton Rabi
- Department of Geosciences, University of Tübingen, Hölderlinstrasse 12, 72074 Tübingen, Germany
- Central Natural Science Collections, Martin Luther University Halle-Wittenberg, Domstraße 4, 06108 Halle (Saale), Germany
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Miedema F, Klein N, Blackburn DG, Sander PM, Maxwell EE, Griebeler EM, Scheyer TM. Heads or tails first? Evolution of fetal orientation in ichthyosaurs, with a scrutiny of the prevailing hypothesis. BMC Ecol Evol 2023; 23:12. [PMID: 37072698 PMCID: PMC10114408 DOI: 10.1186/s12862-023-02110-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 03/21/2023] [Indexed: 04/20/2023] Open
Abstract
According to a longstanding paradigm, aquatic amniotes, including the Mesozoic marine reptile group Ichthyopterygia, give birth tail-first because head-first birth leads to increased asphyxiation risk of the fetus in the aquatic environment. Here, we draw upon published and original evidence to test two hypotheses: (1) Ichthyosaurs inherited viviparity from a terrestrial ancestor. (2) Asphyxiation risk is the main reason aquatic amniotes give birth tail-first. From the fossil evidence, we conclude that head-first birth is more prevalent in Ichthyopterygia than previously recognized and that a preference for tail-first birth likely arose in derived forms. This weakens the support for the terrestrial ancestry of viviparity in Ichthyopterygia. Our survey of extant viviparous amniotes indicates that fetal orientation at birth reflects a broad diversity of factors unrelated to aquatic vs. terrestrial habitat, further undermining the asphyxiation hypothesis. We propose that birth preference is based on parturitional mechanics or carrying efficiency rather than habitat.
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Affiliation(s)
- Feiko Miedema
- Staatliches Museum für Naturkunde Stuttgart, Rosenstein 1, 70191, Stuttgart, Germany.
- Institut für Biologie, Fachgebiet Paläontologie, Hohenheim University, Wollgrasweg 23, 70599, Stuttgart, Germany.
| | - Nicole Klein
- Paläontologisches Institut, Universität Zürich, Karl Schmid-Strasse 4, Zurich, CH-8006, Switzerland
- Abteilung Paläontologie, Institut für Geowissenschaften, Universität Bonn, Nußallee 8, 53115, Bonn, Germany
| | - Daniel G Blackburn
- Dept. of Biology and Electron Microscopy Facility, Trinity College, Hartford, CT, 06106, USA
| | - P Martin Sander
- Abteilung Paläontologie, Institut für Geowissenschaften, Universität Bonn, Nußallee 8, 53115, Bonn, Germany
- Dinosaur Institute, Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, CA, 90007, USA
| | - Erin E Maxwell
- Staatliches Museum für Naturkunde Stuttgart, Rosenstein 1, 70191, Stuttgart, Germany
| | - Eva M Griebeler
- Institut für Organismische und Molekulare Evolution, Universität Mainz, Hanns-Dieter- Hüsch-Weg 15, 55128, Mainz, Germany
| | - Torsten M Scheyer
- Paläontologisches Institut, Universität Zürich, Karl Schmid-Strasse 4, Zurich, CH-8006, Switzerland
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12
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Latimer AE, Sherratt E, Bonnet T, Scheyer TM. Semicircular canal shape diversity among modern lepidosaurs: life habit, size, allometry. BMC Ecol Evol 2023; 23:10. [PMID: 37046214 PMCID: PMC10091843 DOI: 10.1186/s12862-023-02113-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 04/03/2023] [Indexed: 04/14/2023] Open
Abstract
BACKGROUND The shape of the semicircular canals of the inner ear of living squamate reptiles has been used to infer phylogenetic relationships, body size, and life habits. Often these inferences are made without controlling for the effects of the other ones. Here we examine the semicircular canals of 94 species of extant limbed lepidosaurs using three-dimensional landmark-based geometric morphometrics, and analyze them in phylogenetic context to evaluate the relative contributions of life habit, size, and phylogeny on canal shape. RESULTS Life habit is not a strong predictor of semicircular canal shape across this broad sample. Instead, phylogeny plays a major role in predicting shape, with strong phylogenetic signal in shape as well as size. Allometry has a limited role in canal shape, but inner ear size and body mass are strongly correlated. CONCLUSIONS Our wide sampling across limbed squamates suggests that semicircular canal shape and size are predominantly a factor of phylogenetic relatedness. Given the small proportion of variance in semicircular canal shape explained by life habit, it is unlikely that unknown life habit could be deduced from semicircular canal shape alone. Overall, semicircular canal size is a good estimator of body length and even better for body mass in limbed squamates. Semiaquatic taxa tend to be larger and heavier than non-aquatic taxa, but once body size and phylogeny are accounted for, they are hard to distinguish from their non-aquatic relatives based on bony labyrinth shape and morphology.
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Affiliation(s)
- Ashley E Latimer
- Department of Palaeontology, University of Zurich, Karl Schmid-Strasse 4, 8006, Zurich, Switzerland
| | - Emma Sherratt
- School of Biological Sciences, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Timothée Bonnet
- Research School of Biology, Australian National University, Canberra, ACT, 0200, Australia
| | - Torsten M Scheyer
- Department of Palaeontology, University of Zurich, Karl Schmid-Strasse 4, 8006, Zurich, Switzerland.
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13
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Wang W, Spiekman SNF, Zhao L, Rieppel O, Scheyer TM, Fraser NC, Li C. A new long-necked archosauromorph from the Guanling Formation (Anisian, Middle Triassic) of southwestern China and its implications for neck evolution in tanystropheids. Anat Rec (Hoboken) 2023. [PMID: 37029530 DOI: 10.1002/ar.25216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 03/03/2023] [Accepted: 03/10/2023] [Indexed: 04/09/2023]
Abstract
A long neck is an evolutionary innovation convergently appearing in multiple tetrapod lineages, including groups of plesiosaurs, non-archosauriform archosauromorphs, turtles, sauropodomorphs, birds, and mammals. Among all tetrapods both extant and extinct, two Triassic archosauromorphs, Tanystropheus and Dinocephalosaurus, have necks that are particularly elongated relative to the lengths of their trunks. However, the evolutionary history of such hyper-elongated necks in these two archosauromorph clades remains unknown, partially because known close relatives such as Macrocnemus and Pectodens possess only moderately elongated necks. Here, we describe a newly discovered early diverging archosauromorph, Gracilicollum latens gen. et sp. nov., based on a specimen comprising a partial neck and an incompletely preserved skull. The long neck is composed of at least 18 cervical vertebrae. The dentition suggests that this new taxon most likely represents an aquatic piscivore, similar to Dinocephalosaurus and Tanystropheus hydroides. Despite possessing a high number of cervical vertebrae, Gracilicollum gen. nov. is recovered as a tanystropheid in an evolutionary grade between Macrocnemus and Tanystropheus rather than as a close relative of Dinocephalosaurus, a result that is primarily attributable to the presence of palatal teeth and the anatomy of the cervical vertebrae in Gracilicollum gen. nov. Considering the information provided by the new specimen, we provide a detailed discussion of the cervical evolution in dinocephalosaurids and tanystropheids, which is shown to be highly complex and mosaic in nature.
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Affiliation(s)
- Wei Wang
- Key Laboratory of Vertebrate Evolution & Human Origins, CAS Center for Excellence in Life & Paleoenvironment, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, 100044, China
- State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China
| | - Stephan N F Spiekman
- Staatliches Museum für Naturkunde Stuttgart, Rosenstein 1, 70191, Stuttgart, Germany
- Department of Palaeontology, University of Zurich, Karl Schmid-Strasse 4, 8006, Zurich, Switzerland
| | - Lijun Zhao
- Zhejiang Museum of Natural History, 310014, Hangzhou, China
| | - Olivier Rieppel
- Department of Geology, The Field Museum, 1400 S. Lake Shore Drive, Chicago, Illinois, 60605, USA
| | - Torsten M Scheyer
- Department of Palaeontology, University of Zurich, Karl Schmid-Strasse 4, 8006, Zurich, Switzerland
| | | | - Chun Li
- Key Laboratory of Vertebrate Evolution & Human Origins, CAS Center for Excellence in Life & Paleoenvironment, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, 100044, China
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14
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Amson E, Scheyer TM, Martinez Q, Schwermann AH, Koyabu D, He K, Ziegler R. Unique bone microanatomy reveals ancestry of subterranean specializations in mammals. Evol Lett 2022; 6:552-561. [PMID: 36579164 PMCID: PMC9783445 DOI: 10.1002/evl3.303] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 09/06/2022] [Accepted: 09/30/2022] [Indexed: 11/13/2022] Open
Abstract
Acquiring a subterranean lifestyle entails a substantial shift for many aspects of terrestrial vertebrates' biology. Although this lifestyle is associated with multiple instances of convergent evolution, the relative success of some subterranean lineages largely remains unexplained. Here, we focus on the mammalian transitions to life underground, quantifying bone microanatomy through high-resolution X-ray tomography. The true moles stand out in this dataset. Examination of this family's bone histology reveals that the highly fossorial moles acquired a unique phenotype involving large amounts of compacted coarse cancellous bone. This phenotype exceeds the adaptive optimum seemingly shared by several other subterranean mammals and can be traced back to some of the first known members of the family. This remarkable microanatomy was acquired early in the history of the group and evolved faster than the gross morphology innovations of true moles' forelimb. This echoes the pattern described for other lifestyle transitions, such as the acquisition of bone mass specializations in secondarily aquatic tetrapods. Highly plastic traits-such as those pertaining to bone structure-are hence involved in the early stages of different types of lifestyle transitions.
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Affiliation(s)
- Eli Amson
- Staatliches Museum für Naturkunde StuttgartDE‐70191StuttgartGermany
| | - Torsten M. Scheyer
- Palaeontological Institute and MuseumUniversity of ZurichZurichCH‐8006Switzerland
| | - Quentin Martinez
- Staatliches Museum für Naturkunde StuttgartDE‐70191StuttgartGermany
| | - Achim H. Schwermann
- LWL‐Museum für NaturkundeWestfälisches Landesmuseum mit PlanetariumDE‐48161MünsterGermany
| | - Daisuke Koyabu
- Research and Development Center for Precision MedicineUniversity of TsukubaTsukuba305‐8550Japan
| | - Kai He
- Key Laboratory of Conservation and Application in Biodiversity of South China, School of Life SciencesGuangzhou UniversityGuangzhou510006China
| | - Reinhard Ziegler
- Staatliches Museum für Naturkunde StuttgartDE‐70191StuttgartGermany
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15
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Scheyer TM, Klein N, Evers SW, Mautner AK, Pabst B. First evidence of Proganochelys quenstedtii (Testudinata) from the Plateosaurus bonebeds (Norian, Late Triassic) of Frick, Canton Aargau, Switzerland. Swiss J Palaeontol 2022; 141:17. [PMID: 36317153 PMCID: PMC9613585 DOI: 10.1186/s13358-022-00260-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 09/15/2022] [Indexed: 06/16/2023]
Abstract
UNLABELLED Proganochelys quenstedtii represents the best-known stem turtle from the Late Triassic, with gross anatomical and internal descriptions of the shell, postcranial bones and skull based on several well-preserved specimens from Central European fossil locations. We here report on the first specimen of P. quenstedtii from the Late Triassic (Klettgau Formation) Frickberg near the town of Frick, Canton Aargau, Switzerland. Similar to other Late Triassic 'Plateosaurus-bearing bonebeds', Proganochelys is considered to be a rare faunal element in the Swiss locality of Frick as well. The specimen, which is largely complete but was found only partially articulated and mixed with large Plateosaurus bones, overall resembles the morphology of the classical specimens from Germany. Despite being disarticulated, most skull bones could be identified and micro-computed tomography (CT) scanning of the posterior skull region reveals new insights into the braincase and neurovascular anatomy, as well as the inner ear region. These include the presence of a fenestra perilymphatica, potentially elongated cochlear ducts, and intense vascularization of small tubercles on the posterior end of the skull roof, which we interpret as horn cores. Other aspects of the skull in the braincase region, such as the presence or absence of a supratemporal remain ambiguous due to the fusion of individual bones and thus lack of visible sutures (externally and internally). Based on the size of the shell and fusion of individual elements, the specimen is interpreted as a skeletally mature animal. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1186/s13358-022-00260-4.
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Affiliation(s)
- Torsten M. Scheyer
- Palaeontological Institute and Museum, University of Zurich, Karl-Schmid-Strasse 4, 8006 Zurich, Switzerland
| | - Nicole Klein
- Palaeontological Institute and Museum, University of Zurich, Karl-Schmid-Strasse 4, 8006 Zurich, Switzerland
- Institute of Geosciences, Paleontology, University of Bonn, Nussallee 8, 53115 Bonn, Germany
| | - Serjoscha W. Evers
- Department of Geosciences, University of Fribourg, Ch. du Musée 6, 1700 Fribourg, Switzerland
| | - Anna-Katharina Mautner
- Palaeontological Institute and Museum, University of Zurich, Karl-Schmid-Strasse 4, 8006 Zurich, Switzerland
| | - Ben Pabst
- Sauriermuseum Aathal, Zürichstrasse 69, 8607 Aathal-Seegräben, Switzerland
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16
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Herbst EC, Meade LE, Lautenschlager S, Fioritti N, Scheyer TM. A toolbox for the retrodeformation and muscle reconstruction of fossil specimens in Blender. R Soc Open Sci 2022. [PMID: 36039284 DOI: 10.5061/dryad.qjq2bvqk2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Accurate muscle reconstructions can offer new information on the anatomy of fossil organisms and are also important for biomechanical analysis (multibody dynamics and finite-element analysis (FEA)). For the sake of simplicity, muscles are often modelled as point-to-point strands or frustra (cut-off cones) in biomechanical models. However, there are cases in which it is useful to model the muscle morphology in three dimensions, to better examine the effects of muscle shape and size. This is especially important for fossil analyses, where muscle force is estimated from the reconstructed muscle morphology (rather than based on data collected in vivo). The two main aims of this paper are as follows. First, we created a new interactive tool in the free open access software Blender to enable interactive three-dimensional modelling of muscles. This approach can be applied to both palaeontological and human biomechanics research to generate muscle force magnitudes and lines of action for FEA. Second, we provide a guide on how to use existing Blender tools to reconstruct distorted or incomplete specimens. This guide is aimed at palaeontologists but can also be used by anatomists working with damaged specimens or to test functional implication of hypothetical morphologies.
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Affiliation(s)
- Eva C Herbst
- Palaeontological Institute and Museum, University of Zurich, Zurich, Switzerland
| | - Luke E Meade
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK
| | - Stephan Lautenschlager
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK
| | - Niccolo Fioritti
- Department of Cell and Developmental Biology, University College London, London, UK
| | - Torsten M Scheyer
- Palaeontological Institute and Museum, University of Zurich, Zurich, Switzerland
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17
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Herbst EC, Meade LE, Lautenschlager S, Fioritti N, Scheyer TM. A toolbox for the retrodeformation and muscle reconstruction of fossil specimens in Blender. R Soc Open Sci 2022. [PMID: 36039284 DOI: 10.6084/m9.figshare.c.6145965] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Accurate muscle reconstructions can offer new information on the anatomy of fossil organisms and are also important for biomechanical analysis (multibody dynamics and finite-element analysis (FEA)). For the sake of simplicity, muscles are often modelled as point-to-point strands or frustra (cut-off cones) in biomechanical models. However, there are cases in which it is useful to model the muscle morphology in three dimensions, to better examine the effects of muscle shape and size. This is especially important for fossil analyses, where muscle force is estimated from the reconstructed muscle morphology (rather than based on data collected in vivo). The two main aims of this paper are as follows. First, we created a new interactive tool in the free open access software Blender to enable interactive three-dimensional modelling of muscles. This approach can be applied to both palaeontological and human biomechanics research to generate muscle force magnitudes and lines of action for FEA. Second, we provide a guide on how to use existing Blender tools to reconstruct distorted or incomplete specimens. This guide is aimed at palaeontologists but can also be used by anatomists working with damaged specimens or to test functional implication of hypothetical morphologies.
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Affiliation(s)
- Eva C Herbst
- Palaeontological Institute and Museum, University of Zurich, Zurich, Switzerland
| | - Luke E Meade
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK
| | - Stephan Lautenschlager
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK
| | - Niccolo Fioritti
- Department of Cell and Developmental Biology, University College London, London, UK
| | - Torsten M Scheyer
- Palaeontological Institute and Museum, University of Zurich, Zurich, Switzerland
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18
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Herbst EC, Meade LE, Lautenschlager S, Fioritti N, Scheyer TM. A toolbox for the retrodeformation and muscle reconstruction of fossil specimens in Blender. R Soc Open Sci 2022; 9:220519. [PMID: 36039284 PMCID: PMC9399692 DOI: 10.1098/rsos.220519] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 07/27/2022] [Indexed: 05/10/2023]
Abstract
Accurate muscle reconstructions can offer new information on the anatomy of fossil organisms and are also important for biomechanical analysis (multibody dynamics and finite-element analysis (FEA)). For the sake of simplicity, muscles are often modelled as point-to-point strands or frustra (cut-off cones) in biomechanical models. However, there are cases in which it is useful to model the muscle morphology in three dimensions, to better examine the effects of muscle shape and size. This is especially important for fossil analyses, where muscle force is estimated from the reconstructed muscle morphology (rather than based on data collected in vivo). The two main aims of this paper are as follows. First, we created a new interactive tool in the free open access software Blender to enable interactive three-dimensional modelling of muscles. This approach can be applied to both palaeontological and human biomechanics research to generate muscle force magnitudes and lines of action for FEA. Second, we provide a guide on how to use existing Blender tools to reconstruct distorted or incomplete specimens. This guide is aimed at palaeontologists but can also be used by anatomists working with damaged specimens or to test functional implication of hypothetical morphologies.
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Affiliation(s)
- Eva C. Herbst
- Palaeontological Institute and Museum, University of Zurich, Zurich, Switzerland
| | - Luke E. Meade
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK
| | - Stephan Lautenschlager
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK
| | - Niccolo Fioritti
- Department of Cell and Developmental Biology, University College London, London, UK
| | - Torsten M. Scheyer
- Palaeontological Institute and Museum, University of Zurich, Zurich, Switzerland
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19
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Klein N, Furrer H, Ehrbar I, Torres Ladeira M, Richter H, Scheyer TM. A new pachypleurosaur from the Early Ladinian Prosanto Formation in the Eastern Alps of Switzerland. Swiss J Palaeontol 2022; 141:12. [PMID: 35844249 PMCID: PMC9276568 DOI: 10.1186/s13358-022-00254-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 05/26/2022] [Indexed: 06/15/2023]
Abstract
UNLABELLED The Alpine Prosanto Formation (Middle Triassic) cropping out in the Ducan region in eastern Switzerland has yielded a rich fish and reptile fauna. Here, we present new pachypleurosaur remains from the upper part of the formation (Early Ladinian), similar to the previously known pachypleurosaurs from the Middle Triassic UNESCO World Heritage Site of Monte San Giorgio in southern Switzerland/northern Italy. From these remains, a new pachypleurosaur species, Prosantosaurus scheffoldi nov. gen. et spec., is described on the basis of six fairly complete skeletons, one disarticulated specimen and an isolated skull. As is typical for pachypleurosaurs and most other Triassic marine reptiles, the new taxon is based to a large degree on a combination of characters (e.g., nasals articulating broadly with the anterior margins of the prefrontals and lacking posterior processes; postorbitals with rounded anterior processes that articulate with the postfrontals anterolaterally) rather than on many unambiguous autapomorphies, although a few of the latter were found including (1) a premaxilla which is excluded from entering both the external and internal nares and (2) a parietal, which is distinctly longer than wide and carrying distinct anterolaterally angled processes. Phylogenetic relationships of the new taxon are tested within European Pachypleurosauria, revealing that the new species is the sister taxon to a clade including Serpianosaurus, Proneusticosaurus, and the monophyletic Neusticosaurus spp. Mapping of palaeogeographic and stratigraphical distribution of valid European pachypleurosaurs shows that a formerly proposed scenario of migration of pachypleurosaurs from the eastern Palaeotethys during the Olenekian into the Germanic Basin and a subsequent diversification and invasion during the Anisian into the intraplatform basins of the South Alpine realm must be re-assessed. The exceptional preservation and preparation of the Ducan fossils further allow the description of tooth replacement patterns for the first time in a European pachypleurosaur species. The "alveolarization" of replacement teeth, the horizontal replacement pattern, and the subsequent remodelling of the functional alveoli during tooth replacement supports the monophyly of Sauropterygia as discussed before. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1186/s13358-022-00254-2.
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Affiliation(s)
- Nicole Klein
- Palaeontological Institute and Museum, University of Zurich, Karl Schmid-Strasse 4, CH-8006 Zurich, Switzerland
| | - Heinz Furrer
- Palaeontological Institute and Museum, University of Zurich, Karl Schmid-Strasse 4, CH-8006 Zurich, Switzerland
| | - Iris Ehrbar
- Palaeontological Institute and Museum, University of Zurich, Karl Schmid-Strasse 4, CH-8006 Zurich, Switzerland
| | - Marta Torres Ladeira
- Palaeontological Institute and Museum, University of Zurich, Karl Schmid-Strasse 4, CH-8006 Zurich, Switzerland
| | - Henning Richter
- Diagnostic Imaging Research Unit (DIRU), Clinic for Diagnostic Imaging, Department of Clinical Diagnostics and Services, Vetsuisse Faculty, University of Zurich, Winterthurerstrasse 258c, CH-8057 Zurich, Switzerland
| | - Torsten M. Scheyer
- Palaeontological Institute and Museum, University of Zurich, Karl Schmid-Strasse 4, CH-8006 Zurich, Switzerland
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20
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Klein N, Wintrich T, Hagdorn H, Spiller D, Winkelhorst H, Goris G, Scheyer TM. Placodus (Placodontia, Sauropterygia) dentaries from Winterswijk, The Netherlands (middle Anisian) and Hünfeld, Hesse, Germany (late Anisian) with comments on ontogenetic changes. Palaontol Z 2022; 96:289-302. [PMID: 35645412 PMCID: PMC9132834 DOI: 10.1007/s12542-022-00614-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 02/17/2022] [Indexed: 06/15/2023]
Abstract
Two recently found dentaries from the Lower Muschelkalk of Winterswijk (The Netherlands) and from the Upper Muschelkalk of an outcrop in the vicinity of Hünfeld (Hesse, Germany) are studied and compared to lower jaws of placodonts. As a result, the here described specimens can be assigned to Placodus cf. gigas. However, this assignment should be regarded as preliminary due to the isolated nature of the material. More diagnostic material is necessary to validate this affiliation. A certain morphological variability in P. gigas dentaries that had been pointed out before is also obvious among the new material. Placodus gigas has a wide paleogeography and stratigraphic range and a revision of the material assigned to P. gigas with new methods is overdue but beyond the scope of the current paper. The dentary from Hünfeld is with about 4 cm preserved length the smallest so far known dentary of a Placodus. It provides interesting insights in morphological changes during ontogeny and reveals differences in trajectories when compared to dentaries of different ontogenetic stages of Cyamodus hildegardis.
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Affiliation(s)
- Nicole Klein
- Paleontological Institute and Museum, University of Zurich, Karl-Schmid-Strasse 4, 8006 Zurich, Switzerland
- Institute of Geosciences, Paleontology, University of Bonn, Nussallee 8, 53115 Bonn, Germany
| | - Tania Wintrich
- Institute of Geosciences, Paleontology, University of Bonn, Nussallee 8, 53115 Bonn, Germany
| | - Hans Hagdorn
- Muschelkalkmuseum Hagdorn, Schloßstraße 11, 74653 Ingelfingen, Germany
| | - Dave Spiller
- Dave Spiller, Liebrechtstrasse 44a, 46240 Bottrop, Germany
| | | | - Gerard Goris
- Gerard Goris, Kolmschotlanden 43, 7542 Enschede, The Netherlands
| | - Torsten M. Scheyer
- Paleontological Institute and Museum, University of Zurich, Karl-Schmid-Strasse 4, 8006 Zurich, Switzerland
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21
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Scheyer TM, Oberli U, Klein N, Furrer H. A large osteoderm-bearing rib from the Upper Triassic Kössen Formation (Norian/Rhaetian) of eastern Switzerland. Swiss J Palaeontol 2022; 141:1. [PMID: 35250843 PMCID: PMC8866377 DOI: 10.1186/s13358-022-00244-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 01/21/2022] [Indexed: 06/14/2023]
Abstract
An important component of the Alpine vertebrate record of Late Triassic age derives from the Kössen Formation, which crops out extensively in the eastern Alps. Here, we present an isolated and only partially preserved large rib, which carries an osteoderm on a low uncinate process. Osteological comparison indicates that the specimen likely belongs to a small clade of marine reptiles, Saurosphargidae. Members of the clade are restricted to the western (today Europe) and eastern margins of the Tethys (today China) and were so far known only from the Anisian stage of the Middle Triassic. The assignment of the new find to cf. Saurosphargidae, with potential affinities to the genus Largocephalosaurus from the Guanling Formation of Yunnan and Guizhou Provinces, China, would extend the occurrence of the clade about 35 million years into the Late Triassic.
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Affiliation(s)
- Torsten M. Scheyer
- Universität Zürich, Paläontologisches Institut und Museum, Karl Schmid-Strasse 4, CH-8006 Zürich, Switzerland
| | - Urs Oberli
- Waldgutstrasse 21, CH-9010 St.Gallen, Switzerland
| | - Nicole Klein
- Universität Zürich, Paläontologisches Institut und Museum, Karl Schmid-Strasse 4, CH-8006 Zürich, Switzerland
| | - Heinz Furrer
- Universität Zürich, Paläontologisches Institut und Museum, Karl Schmid-Strasse 4, CH-8006 Zürich, Switzerland
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22
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Maidment SCR, Strachan SJ, Ouarhache D, Scheyer TM, Brown EE, Fernandez V, Johanson Z, Raven TJ, Barrett PM. Bizarre dermal armour suggests the first African ankylosaur. Nat Ecol Evol 2021; 5:1576-1581. [PMID: 34556830 DOI: 10.1038/s41559-021-01553-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 08/09/2021] [Indexed: 11/09/2022]
Abstract
Ankylosauria is a diverse clade of armoured dinosaurs whose members were important constituents of many Cretaceous faunas. Phylogenetic analyses imply that the clade diverged from its sister taxon, Stegosauria, during the late Early Jurassic, but the fossil records of both clades are sparse until the Late Jurassic (~150 million years ago). Moreover, Ankylosauria is almost entirely restricted to former Laurasian continents, with only a single valid Gondwanan taxon. Spicomellus afer gen. et sp. nov. appears to represent the earliest-known ankylosaur and the first to be named from Africa, from the Middle Jurassic (Bathonian-Callovian) of Morocco, filling an important gap in dinosaur evolution. The specimen consists of a rib with spiked dermal armour fused to its dorsal surface, an unprecedented morphology among extinct and extant vertebrates. The specimen reveals an unrealized morphological diversity of armoured dinosaurs during their early evolution, and implies the presence of an important but undiscovered Gondwanan fossil record.
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Affiliation(s)
- Susannah C R Maidment
- Department of Earth Sciences, Natural History Museum, London, UK. .,School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK.
| | - Sarah J Strachan
- Department of Earth Sciences, University College London, London, UK
| | - Driss Ouarhache
- GERA Laboratory, Faculty of Sciences Dhar El Mahraz, SMBA University, Fez, Morocco
| | - Torsten M Scheyer
- Palaeontological Institute and Museum, University of Zurich, Zurich, Switzerland
| | - Emily E Brown
- Department of Earth Sciences, Natural History Museum, London, UK.,School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK
| | | | - Zerina Johanson
- Department of Earth Sciences, Natural History Museum, London, UK
| | - Thomas J Raven
- Department of Earth Sciences, Natural History Museum, London, UK.,School of Environment and Technology, University of Brighton, Brighton, UK
| | - Paul M Barrett
- Department of Earth Sciences, Natural History Museum, London, UK.,Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
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23
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Georgalis GL, Scheyer TM. Lizards and snakes from the earliest Miocene of Saint-Gérand-le-Puy, France: an anatomical and histological approach of some of the oldest Neogene squamates from Europe. BMC Ecol Evol 2021; 21:144. [PMID: 34256702 PMCID: PMC8278609 DOI: 10.1186/s12862-021-01874-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 06/28/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The earliest Miocene (Aquitanian) represents a crucial time interval in the evolution of European squamates (i.e., lizards and snakes), witnessing a high diversity of taxa, including an array of extinct forms but also representatives of extant genera. We here conduct a taxonomical survey along with a histological/microanatomical approach on new squamate remains from the earliest Miocene of Saint-Gérand-le-Puy, France, an area that has been well known for its fossil discoveries since the nineteenth century. RESULTS We document new occurrences of taxa, among which, the lacertid Janosikia and the anguid Ophisaurus holeci, were previously unknown from France. We provide a detailed description of the anatomical structures of the various cranial and postcranial remains of lizards and snakes from Saint-Gérand-le-Puy. By applying micro-CT scanning in the most complete cranial elements of our sample, we decipher previously unknown microanatomical features. We report in detail the subsurface distribution and 3D connectivity of vascular channels in the anguid parietal. The fine meshwork of channels and cavities or sinuses in the parietal of Ophisaurus could indicate some thermoregulatory function, as it has recently been demonstrated for other vertebrate groups, providing implications for the palaeophysiology of this earliest Miocene anguine lizard. CONCLUSIONS A combination of anatomical and micro-anatomical/histological approach, aided by micro-CT scanning, enabled the documentation of these new earliest Miocene squamate remains. A distinct geographic expansion is provided for the extinct anguine Ophisaurus holeci and the lacertid Janosikia (the closest relative of the extant insular Gallotia from the Canary Islands).
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Affiliation(s)
- Georgios L Georgalis
- University of Zurich, Palaeontological Institute and Museum, Karl Schmid-Strasse 4, 8006, Zurich, Switzerland.
| | - Torsten M Scheyer
- University of Zurich, Palaeontological Institute and Museum, Karl Schmid-Strasse 4, 8006, Zurich, Switzerland
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24
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Pommery Y, Scheyer TM, Neenan JM, Reich T, Fernandez V, Voeten DFAE, Losko AS, Werneburg I. Dentition and feeding in Placodontia: tooth replacement in Henodus chelyops. BMC Ecol Evol 2021; 21:136. [PMID: 34225664 PMCID: PMC8256584 DOI: 10.1186/s12862-021-01835-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 05/17/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Placodontia is a Triassic sauropterygian reptile group characterized by flat and enlarged crushing teeth adapted to a durophagous diet. The enigmatic placodont Henodus chelyops has numerous autapomorphic character states, including extreme tooth count reduction to only a single pair of palatine and dentary crushing teeth. This renders the species unusual among placodonts and challenges identification of its phylogenetic position. RESULTS The skulls of two Henodus chelyops specimens were visualized with synchrotron tomography to investigate the complete anatomy of their functional and replacement crushing dentition in 3D. All teeth of both specimens were segmented, measured, and statistically compared to reveal that H. chelyops teeth are much smaller than the posterior palatine teeth of other cyamodontoid placodonts with the exception of Parahenodus atancensis from the Iberian Peninsula. The replacement teeth of this species are quite similar in size and morphology to the functional teeth. CONCLUSION As other placodonts, Henodus chelyops exhibits vertical tooth replacement. This suggests that vertical tooth replacement arose relatively early in placodont phylogeny. Analysis of dental morphology in H. chelyops revealed a concave shape of the occlusal surface and the notable absence of a central cusp. This dental morphology could have reduced dental wear and protected against failure. Hence, the concave teeth of H. chelyops appear to be adapted to process small invertebrate items, such as branchiopod crustaceans. Small gastropods were encountered in the matrix close to both studied skulls.
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Affiliation(s)
- Yannick Pommery
- Senckenberg Centre for Human Evolution and Palaeoenvironment (HEP) an der Eberhard-Karls-Universität Tübingen, Sigwartstraße 10, 72076, Tübingen, Germany.,Fachbereich Geowissenschaften, Eberhard-Karls-Universität Tübingen, Hölderlinstraße 12, 72074, Tübingen, Germany.,Université de Bourgogne-Franche-Comté, Esplanade Erasme, 21000, Dijon, France
| | - Torsten M Scheyer
- Universität Zürich, Paläontologisches Institut und Museum, Karl Schmid-Strasse 4, 8006, Zürich, Switzerland
| | - James M Neenan
- Oxford University Museum of Natural History, University of Oxford, Oxford, UK
| | - Tobias Reich
- Universität Zürich, Paläontologisches Institut und Museum, Karl Schmid-Strasse 4, 8006, Zürich, Switzerland
| | - Vincent Fernandez
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38000, Grenoble, France.,The Natural History Museum, Cromwell Road, London, SW7 5BD, UK
| | - Dennis F A E Voeten
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38000, Grenoble, France.,Department of Organismal Biology, Uppsala University, Norbyvägen 18 A, 752 36, Uppsala, Sweden.,Naturalis Biodiversity Center, Darwinweg 2, 2333 CR, Leiden, the Netherlands
| | - Adrian S Losko
- Forschungs-Neutronenquelle Heinz Maier-Leibnitz, Lichtenbergstr. 1, 85748, Garching, Germany
| | - Ingmar Werneburg
- Senckenberg Centre for Human Evolution and Palaeoenvironment (HEP) an der Eberhard-Karls-Universität Tübingen, Sigwartstraße 10, 72076, Tübingen, Germany. .,Fachbereich Geowissenschaften, Eberhard-Karls-Universität Tübingen, Hölderlinstraße 12, 72074, Tübingen, Germany.
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25
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Bindellini G, Wolniewicz AS, Miedema F, Scheyer TM, Dal Sasso C. Cranial anatomy of Besanosaurus leptorhynchus Dal Sasso & Pinna, 1996 (Reptilia: Ichthyosauria) from the Middle Triassic Besano Formation of Monte San Giorgio, Italy/Switzerland: taxonomic and palaeobiological implications. PeerJ 2021; 9:e11179. [PMID: 33996277 PMCID: PMC8106916 DOI: 10.7717/peerj.11179] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 03/08/2021] [Indexed: 12/20/2022] Open
Abstract
Besanosaurus leptorhynchus Dal Sasso & Pinna, 1996 was described on the basis of a single fossil excavated near Besano (Italy) nearly three decades ago. Here, we re-examine its cranial osteology and assign five additional specimens to B. leptorhynchus, four of which were so far undescribed. All of the referred specimens were collected from the Middle Triassic outcrops of the Monte San Giorgio area (Italy/Switzerland) and are housed in various museum collections in Europe. The revised diagnosis of the taxon includes the following combination of cranial characters: extreme longirostry; an elongate frontal not participating in the supratemporal fenestra; a prominent 'triangular process' of the quadrate; a caudoventral exposure of the postorbital on the skull roof; a prominent coronoid (preglenoid) process of the surangular; tiny conical teeth with coarsely-striated crown surfaces and deeply-grooved roots; mesial maxillary teeth set in sockets; distal maxillary teeth set in a short groove. All these characters are shared with the holotype of Mikadocephalus gracilirostris Maisch & Matzke, 1997, which we consider as a junior synonym of B. leptorhynchus. An updated phylogenetic analysis, which includes revised scores for B. leptorhynchus and several other shastasaurids, recovers B. leptorhynchus as a basal merriamosaurian, but it is unclear if Shastasauridae form a clade, or represent a paraphyletic group. The inferred body length of the examined specimens ranges from 1 m to about 8 m. The extreme longirostry suggests that B. leptorhynchus primarily fed on small and elusive prey, feeding lower in the food web than an apex predator: a novel ecological specialisation never reported before the Anisian in a large diapsid. This specialization might have triggered an increase of body size and helped to maintain low competition among the diverse ichthyosaur fauna of the Besano Formation.
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Affiliation(s)
- Gabriele Bindellini
- Dipartimento di Scienze della Terra “Ardito Desio”, Università degli Studi di Milano, Milano, Italy
| | | | - Feiko Miedema
- Staatliches Museum für Naturkunde Stuttgart, Stuttgart, Germany
- Paläontologisches Institut und Museum, Universität Zürich, Zürich, Switzerland
| | - Torsten M. Scheyer
- Paläontologisches Institut und Museum, Universität Zürich, Zürich, Switzerland
| | - Cristiano Dal Sasso
- Sezione di Paleontologia dei Vertebrati, Museo di Storia Naturale di Milano, Milano, Italy
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26
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Spiekman SN, Fraser NC, Scheyer TM. A new phylogenetic hypothesis of Tanystropheidae (Diapsida, Archosauromorpha) and other "protorosaurs", and its implications for the early evolution of stem archosaurs. PeerJ 2021; 9:e11143. [PMID: 33986981 PMCID: PMC8101476 DOI: 10.7717/peerj.11143] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 03/02/2021] [Indexed: 12/15/2022] Open
Abstract
The historical clade "Protorosauria" represents an important group of archosauromorph reptiles that had a wide geographic distribution between the Late Permian and Late Triassic. "Protorosaurs" are characterized by their long necks, which are epitomized in the genus Tanystropheus and in Dinocephalosaurus orientalis. Recent phylogenetic analyses have indicated that "Protorosauria" is a polyphyletic clade, but the exact relationships of the various "protorosaur" taxa within the archosauromorph lineage is currently uncertain. Several taxa, although represented by relatively complete material, have previously not been assessed phylogenetically. We present a new phylogenetic hypothesis that comprises a wide range of archosauromorphs, including the most exhaustive sample of "protorosaurs" to date and several "protorosaur" taxa from the eastern Tethys margin that have not been included in any previous analysis. The polyphyly of "Protorosauria" is confirmed and therefore we suggest the usage of this term should be abandoned. Tanystropheidae is recovered as a monophyletic group and the Chinese taxa Dinocephalosaurus orientalis and Pectodens zhenyuensis form a new archosauromorph clade, Dinocephalosauridae, which is closely related to Tanystropheidae. The well-known crocopod and former "protorosaur" Prolacerta broomi is considerably less closely related to Archosauriformes than was previously considered.
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Affiliation(s)
| | | | - Torsten M. Scheyer
- University of Zurich, Palaeontological Institute and Museum, Zurich, Switzerland
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27
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Carrillo-Briceño JD, Sánchez R, Scheyer TM, Carrillo JD, Delfino M, Georgalis GL, Kerber L, Ruiz-Ramoni D, Birindelli JLO, Cadena EA, Rincón AF, Chavez-Hoffmeister M, Carlini AA, Carvalho MR, Trejos-Tamayo R, Vallejo F, Jaramillo C, Jones DS, Sánchez-Villagra MR. A Pliocene-Pleistocene continental biota from Venezuela. Swiss J Palaeontol 2021; 140:9. [PMID: 34721281 PMCID: PMC8550326 DOI: 10.1186/s13358-020-00216-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 12/25/2020] [Indexed: 06/13/2023]
Abstract
The Pliocene-Pleistocene transition in the Neotropics is poorly understood despite the major climatic changes that occurred at the onset of the Quaternary. The San Gregorio Formation, the younger unit of the Urumaco Sequence, preserves a fauna that documents this critical transition. We report stingrays, freshwater bony fishes, amphibians, crocodiles, lizards, snakes, aquatic and terrestrial turtles, and mammals. A total of 49 taxa are reported from the Vergel Member (late Pliocene) and nine taxa from the Cocuiza Member (Early Pleistocene), with 28 and 18 taxa reported for the first time in the Urumaco sequence and Venezuela, respectively. Our findings include the first fossil record of the freshwater fishes Megaleporinus, Schizodon, Amblydoras, Scorpiodoras, and the pipesnake Anilius scytale, all from Pliocene strata. The late Pliocene and Early Pleistocene ages proposed here for the Vergel and Cocuiza members, respectively, are supported by their stratigraphic position, palynology, nannoplankton, and 86Sr/88Sr dating. Mammals from the Vergel Member are associated with the first major pulse of the Great American Biotic Interchange. In contrast to the dry conditions prevailing today, the San Gregorio Formation documents mixed open grassland/forest areas surrounding permanent freshwater systems, following the isolation of the northern South American basin from western Amazonia. These findings support the hypothesis that range contraction of many taxa to their current distribution in northern South America occurred rapidly during at least the last 1.5 million years.
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Affiliation(s)
- Jorge D. Carrillo-Briceño
- Universität Zürich, Paläontologisches Institut und Museum, Karl-Schmid-Straße 4, 8006 Zurich, Switzerland
| | - Rodolfo Sánchez
- Museo Paleontológico de Urumaco, Calle Bolívar s/n, Urumaco, Estado Falcón Venezuela
| | - Torsten M. Scheyer
- Universität Zürich, Paläontologisches Institut und Museum, Karl-Schmid-Straße 4, 8006 Zurich, Switzerland
| | - Juan D. Carrillo
- CR2P, Muséum National d’Histoire Naturelle, CNRS, Sorbonne Université, 8 Rue Buffon, 75005 Paris, France
- Gothenburg Global Biodiversity Centre, Carl Skottsbergs gata 22B, 41319 Gothenburg, Sweden
| | - Massimo Delfino
- Dipartimento di Scienze della Terra, Università di Torino, Via Valperga Caluso 35, 10125 Torino, Italy
- Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona, Edifici ICTA/ICP, c/Columnes s/n, Campus de la UAB, 08193 Cerdanyola del Vallès, Barcelona Spain
| | - Georgios L. Georgalis
- Universität Zürich, Paläontologisches Institut und Museum, Karl-Schmid-Straße 4, 8006 Zurich, Switzerland
| | - Leonardo Kerber
- Centro de Apoio à Pesquisa Paleontológica da Quarta Colônia (CAPPA), Universidade Federal de Santa Maria (UFSM), São João do Polêsine, Rio Grande do Sul Brazil
- Museu Paraense Emílio Goeldi, Coordenação de Ciências da Terra e Ecologia, Belém, PA Brazil
| | - Damián Ruiz-Ramoni
- Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja (CRILAR), Provincia de La Rioja, CONICET, UNLaR, SEGEMAR, UNCa, Entre Ríos y Mendoza s/n, 5301 Anillaco, La Rioja, Argentina
| | - José L. O. Birindelli
- Departamento de Biologia Animal e Vegetal, Universidade Estadual de Londrina, Londrina, Brazil
| | - Edwin-Alberto Cadena
- Grupo de Investigación Paleontología Neotropical Tradicional y Molecular (PaleoNeo), Facultad de Ciencias Naturales, Universidad del Rosario, Bogotá, Colombia
- Smithsonian Tropical Research Institute, Apartado, 0843-03092 Balboa, Ancón Panama
| | - Aldo F. Rincón
- Departamento de Física y Geociencias, Universidad del Norte, Km. 5 Vía Puerto Colombia, Barranquilla, Colombia
| | - Martin Chavez-Hoffmeister
- Laboratorio de Paleontología, Instituto de Ciencias de La Tierra, Universidad Austral de Chile, Valdivia, Chile
| | - Alfredo A. Carlini
- Lab. Morfología Evolutiva Desarrollo (MORPHOS), and División Paleontología de Vertebrados, Museo de La Plata, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, Paseo del Bosque s/n, B1900FWA La Plata, Argentina
| | - Mónica R. Carvalho
- Smithsonian Tropical Research Institute, Apartado, 0843-03092 Balboa, Ancón Panama
| | - Raúl Trejos-Tamayo
- Instituto de Investigaciones en Estratigrafía (IIES), Universidad de Caldas, Calle 65 #26-10, Manizales, Colombia
- Departamento de Geología, Universidad de Salamanca, 37008 Salamanca, Spain
| | - Felipe Vallejo
- Instituto de Investigaciones en Estratigrafía (IIES), Universidad de Caldas, Calle 65 #26-10, Manizales, Colombia
- Departamento de Geología, Universidad de Salamanca, 37008 Salamanca, Spain
| | - Carlos Jaramillo
- Smithsonian Tropical Research Institute, Apartado, 0843-03092 Balboa, Ancón Panama
- Departamento de Geología, Universidad de Salamanca, 37008 Salamanca, Spain
- ISEM, U. Montpellier, CNRS, EPHE, IRD, Montpellier, France
| | - Douglas S. Jones
- Florida Museum of Natural History, University of Florida, Gainesville, FL 32611 USA
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28
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Rössner GE, Costeur L, Scheyer TM. Antiquity and fundamental processes of the antler cycle in Cervidae (Mammalia). Naturwissenschaften 2020; 108:3. [PMID: 33326046 PMCID: PMC7744388 DOI: 10.1007/s00114-020-01713-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 11/02/2020] [Accepted: 11/23/2020] [Indexed: 12/12/2022]
Abstract
The origins of the regenerative nature of antlers, being branched and deciduous apophyseal appendages of frontal bones of cervid artiodactyls, have long been associated with permanent evolutionary precursors. In this study, we provide novel insight into growth modes of evolutionary early antlers. We analysed a total of 34 early antlers affiliated to ten species, including the oldest known, dating from the early and middle Miocene (approx. 18 to 12 million years old) of Europe. Our findings provide empirical data from the fossil record to demonstrate that growth patterns and a regular cycle of necrosis, abscission and regeneration are consistent with data from modern antlers. The diverse histological analyses indicate that primary processes and mechanisms of the modern antler cycle were not gradually acquired during evolution, but were fundamental from the earliest record of antler evolution and, hence, explanations why deer shed antlers have to be rooted in basic histogenetic mechanisms. The previous interpretation that proximal circular protuberances, burrs, are the categorical traits for ephemerality is refuted.
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Affiliation(s)
- Gertrud E. Rössner
- Staatliche Naturwissenschaftliche Sammlungen Bayerns - Bayerische Staatssammlung für Paläontologie und Geologie, Richard Wagner Str. 10, 80333 München, Germany
- Department für Geo- und Umweltwissenschaften, Ludwig-Maximilians-Universität München, Richard-Wagner-Str. 10, 80333 München, Germany
| | - Loïc Costeur
- Naturhistorisches Museum Basel, Augustinergasse 2, 4001 Basel, Switzerland
| | - Torsten M. Scheyer
- Universität Zürich, Paläontologisches Institut und Museum, Karl Schmid-Strasse 4, 8006 Zürich, Switzerland
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29
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Spiekman SNF, Neenan JM, Fraser NC, Fernandez V, Rieppel O, Nosotti S, Scheyer TM. The cranial morphology of Tanystropheus hydroides (Tanystropheidae, Archosauromorpha) as revealed by synchrotron microtomography. PeerJ 2020; 8:e10299. [PMID: 33240633 PMCID: PMC7682440 DOI: 10.7717/peerj.10299] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 10/14/2020] [Indexed: 12/19/2022] Open
Abstract
The postcranial morphology of the extremely long-necked Tanystropheus hydroides is well-known, but observations of skull morphology were previously limited due to compression of the known specimens. Here we provide a detailed description of the skull of PIMUZ T 2790, including a partial endocast and endosseous labyrinth, based on synchrotron microtomographic data, and compare its morphology to that of other early Archosauromorpha. In many features, such as the wide and flattened snout and the configuration of the temporal and palatal regions, Tanystropheus hydroides differs strongly from other early archosauromorphs. The braincase possesses a combination of derived archosaur traits, such as the presence of a laterosphenoid and the ossification of the lateral wall of the braincase, but also differs from archosauriforms in the morphology of the ventral ramus of the opisthotic, the horizontal orientation of the parabasisphenoid, and the absence of a clearly defined crista prootica. Tanystropheus hydroides was a ram-feeder that likely caught its prey through a laterally directed snapping bite. Although the cranial morphology of other archosauromorph lineages is relatively well-represented, the skulls of most tanystropheid taxa remain poorly understood due to compressed and often fragmentary specimens. The recent descriptions of the skulls of Macrocnemus bassanii and now Tanystropheus hydroides reveal a large cranial disparity in the clade, reflecting wide ecological diversity, and highlighting the importance of non-archosauriform Archosauromorpha to both terrestrial and aquatic ecosystems during the Triassic.
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Affiliation(s)
- Stephan N F Spiekman
- University of Zurich, Palaeontological Institute and Museum, Zurich, Switzerland
| | | | | | - Vincent Fernandez
- European Synchrotron Radiation Facility, Grenoble, France.,The Natural History Museum, London, UK
| | | | | | - Torsten M Scheyer
- University of Zurich, Palaeontological Institute and Museum, Zurich, Switzerland
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30
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Spiekman SN, Neenan JM, Fraser NC, Fernandez V, Rieppel O, Nosotti S, Scheyer TM. Aquatic Habits and Niche Partitioning in the Extraordinarily Long-Necked Triassic Reptile Tanystropheus. Curr Biol 2020; 30:3889-3895.e2. [DOI: 10.1016/j.cub.2020.07.025] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 06/30/2020] [Accepted: 07/08/2020] [Indexed: 12/13/2022]
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Clarac F, Scheyer TM, Desojo JB, Cerda IA, Sanchez S. The evolution of dermal shield vascularization in Testudinata and Pseudosuchia: phylogenetic constraints versus ecophysiological adaptations. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190132. [PMID: 31928197 PMCID: PMC7017437 DOI: 10.1098/rstb.2019.0132] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/01/2019] [Indexed: 01/18/2023] Open
Abstract
Studies on living turtles have demonstrated that shells are involved in the resistance to hypoxia during apnea via bone acidosis buffering; a process which is complemented with cutaneous respiration, transpharyngeal and cloacal gas exchanges in the soft-shell turtles. Bone acidosis buffering during apnea has also been identified in crocodylian osteoderms, which are also known to employ heat transfer when basking. Although diverse, many of these functions rely on one common trait: the vascularization of the dermal shield. Here, we test whether the above ecophysiological functions played an adaptive role in the evolutionary transitions between land and aquatic environments in both Pseudosuchia and Testudinata. To do so, we measured the bone porosity as a proxy for vascular density in a set of dermal plates before performing phylogenetic comparative analyses. For both lineages, the dermal plate porosity obviously varies depending on the animal lifestyle, but these variations prove to be highly driven by phylogenetic relationships. We argue that the complexity of multi-functional roles of the post-cranial dermal skeleton in both Pseudosuchia and Testudinata probably is the reason for a lack of obvious physiological signal, and we discuss the role of the dermal shield vascularization in the evolution of these groups. This article is part of the theme issue 'Vertebrate palaeophysiology'.
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Affiliation(s)
- François Clarac
- Department of Organismal Biology, Subdepartment of Evolution and Development, Uppsala University, Norbyvägen 18A, 752 36 Uppsala, Sweden
| | - Torsten M. Scheyer
- Paleontological Institute and Museum, University of Zurich, Karl Schmid-Strasse 4, 8006 Zurich, Switzerland
| | - Julia B. Desojo
- CONICET, División Paleontología Vertebrados, Museo de La Plata, Paseo del Bosque s/n°, B1900FWA La Plata, Argentina
| | - Ignacio A. Cerda
- CONICET, Argentina y Instituto de Investigacion en Paleobiología y Geología, Universidad Nacional de Río Negro, Museo Carlos Ameghino, Belgrano 1700, Paraje Pichi Ruca (predio Marabunta), 8300 Cipolletti, Río Negro, Argentina
| | - Sophie Sanchez
- Department of Organismal Biology, Subdepartment of Evolution and Development, Uppsala University, Norbyvägen 18A, 752 36 Uppsala, Sweden
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, CS-40220, 38043 Grenoble Cedex, France
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Scheyer TM, Spiekman SNF, Sues HD, Ezcurra MD, Butler RJ, Jones MEH. Colobops: a juvenile rhynchocephalian reptile (Lepidosauromorpha), not a diminutive archosauromorph with an unusually strong bite. R Soc Open Sci 2020; 7:192179. [PMID: 32269817 PMCID: PMC7137947 DOI: 10.1098/rsos.192179] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 02/27/2020] [Indexed: 05/08/2023]
Abstract
Correctly identifying taxa at the root of major clades or the oldest clade-representatives is critical for meaningful interpretations of evolution. A small, partially crushed skull from the Late Triassic (Norian) of Connecticut, USA, originally described as an indeterminate rhynchocephalian saurian, was recently named Colobops noviportensis and reinterpreted as sister to all remaining Rhynchosauria, one of the earliest and globally distributed groups of herbivorous reptiles. It was also interpreted as having an exceptionally reinforced snout and powerful bite based on an especially large supratemporal fenestra. Here, after a re-analysis of the original scan data, we show that the skull was strongly dorsoventrally compressed post-mortem, with most bones out of life position. The cranial anatomy is consistent with that of other rhynchocephalian lepidosauromorphs, not rhynchosaurs. The 'reinforced snout' region and the 'exceptionally enlarged temporal region' are preservational artefacts and not exceptional among clevosaurid rhynchocephalians. Colobops is thus not a key taxon for understanding diapsid feeding apparatus evolution.
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Affiliation(s)
- Torsten M. Scheyer
- Universität Zürich, Paläontologisches Institut und Museum, Karl Schmid-Strasse 4, Zurich CH-8006, Switzerland
| | - Stephan N. F. Spiekman
- Universität Zürich, Paläontologisches Institut und Museum, Karl Schmid-Strasse 4, Zurich CH-8006, Switzerland
| | - Hans-Dieter Sues
- Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, MRC 121, Washington, DC 20560, USA
| | - Martín D. Ezcurra
- Sección Paleontología de Vertebrados, CONICET-Museo Argentino de Ciencias Naturales, Ángel Gallardo 470, C1405DJR, Buenos Aires, Argentina
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Richard J. Butler
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Marc E. H. Jones
- Research Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
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Scheyer TM, Hutchinson JR, Strauss O, Delfino M, Carrillo-Briceño JD, Sánchez R, Sánchez-Villagra MR. Giant extinct caiman breaks constraint on the axial skeleton of extant crocodylians. eLife 2019; 8:e49972. [PMID: 31843051 PMCID: PMC6917493 DOI: 10.7554/elife.49972] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 10/24/2019] [Indexed: 12/20/2022] Open
Abstract
The number of precaudal vertebrae in all extant crocodylians is remarkably conservative, with nine cervicals, 15 dorsals and two sacrals, a pattern present also in their closest extinct relatives. The consistent vertebral count indicates a tight control of axial patterning by Hox genes during development. Here we report on a deviation from this pattern based on an associated skeleton of the giant caimanine Purussaurus, a member of crown Crocodylia, and several other specimens from the Neogene of the northern neotropics. P. mirandai is the first crown-crocodylian to have three sacrals, two true sacral vertebrae and one non-pathological and functional dorsosacral, to articulate with the ilium (pelvis). The giant body size of this caiman relates to locomotory and postural changes. The iliosacral configuration, a more vertically oriented pectoral girdle, and low torsion of the femoral head relative to the condyles are hypothesized specializations for more upright limb orientation or weight support.
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Affiliation(s)
- Torsten M Scheyer
- University of Zurich, Palaeontological Institute and MuseumZurichSwitzerland
| | - John R Hutchinson
- Structure & Motion LaboratoryDepartment of Comparative Biomedical Sciences, The Royal Veterinary CollegeHatfieldUnited Kingdom
| | - Olivier Strauss
- University of Zurich, Palaeontological Institute and MuseumZurichSwitzerland
| | - Massimo Delfino
- Dipartimento di Scienze della Terra, Università di TorinoTorinoItaly
- Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de BarcelonaBarcelonaSpain
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Schoch RR, Klein N, Scheyer TM, Sues HD. Microanatomy of the stem-turtle Pappochelys rosinae indicates a predominantly fossorial mode of life and clarifies early steps in the evolution of the shell. Sci Rep 2019; 9:10430. [PMID: 31320733 PMCID: PMC6639533 DOI: 10.1038/s41598-019-46762-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 07/04/2019] [Indexed: 11/09/2022] Open
Abstract
Unlike any other tetrapod, turtles form their dorsal bony shell (carapace) not from osteoderms, but by contribution of the ribs and vertebrae that expand into the dermis to form plate-like shell components. Although this was known from embryological studies in extant turtles, important steps in this evolutionary sequence have recently been highlighted by the Triassic taxa Pappochelys, Eorhynchochelys and Odontochelys, and the Permian Eunotosaurus. The discovery of Pappochelys shed light on the origin of the ventral bony shell (plastron), which formed from enlarged gastralia. A major question is whether the turtle shell evolved in the context of a terrestrial or aquatic environment. Whereas Odontochelys was controversially interpreted as aquatic, a terrestrial origin of turtles was proposed based on evidence of fossorial adaptations in Eunotosaurus. We report palaeohistological data for Pappochelys, a taxon that exemplifies earlier evolutionary stages in the formation of the bony shell than Odontochelys. Bone histological evidence reveals (1) evolutionary changes in bone microstructure in ribs and gastralia approaching the turtle condition and (2) evidence for a predominantly amphibious or fossorial mode of life in Pappochelys, which support the hypothesis that crucial steps in the evolution of the shell occurred in a terrestrial rather than fully aquatic environment.
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Affiliation(s)
- Rainer R Schoch
- Staatliches Museum für Naturkunde Stuttgart, Rosenstein 1, D-70191, Stuttgart, Germany.
| | - Nicole Klein
- Staatliches Museum für Naturkunde Stuttgart, Rosenstein 1, D-70191, Stuttgart, Germany
- Institut für Geowissenschaften, Abteilung Paläontologie, Nussallee 8, 53115, Bonn, Germany
| | - Torsten M Scheyer
- Universität Zürich, Paläontologisches Institut und Museum, Karl-Schmid-Strasse 4, CH-8006, Zurich, Switzerland.
| | - Hans-Dieter Sues
- Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, MRC 121, Washington, DC, 20560, USA
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Butler RJ, Jones AS, Buffetaut E, Mandl GW, Scheyer TM, Schultz O. Description and phylogenetic placement of a new marine species of phytosaur (Archosauriformes: Phytosauria) from the Late Triassic of Austria. Zool J Linn Soc 2019. [DOI: 10.1093/zoolinnean/zlz014] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
AbstractPhytosaurs are a group of carnivorous, semi-aquatic archosaurian reptiles that attained an almost global distribution during the Late Triassic. We here describe a new species of the phytosaur genus Mystriosuchus from the Norian Dachstein Limestone of Austria, from a marine lagoonal depositional environment. The new Austrian material comprises remains of at least four individuals of similar size (c. 4 m in total length) found in association but disarticulated, and includes one complete and two partial skulls and postcrania. All of these specimens apparently represent a single taxon, which is distinguished by numerous anatomical features from the two previously named Mystriosuchus species. Maximum parsimony analysis of a comprehensive morphological dataset provides strong statistical support for the phylogenetic position of the new Austrian taxon in Mystriosuchus, as the sister taxon to a clade comprising M. planirostris and M. westphali. Histological analysis suggests that the Austrian phytosaur specimens represent individuals that were at least eight years old at time of death, but which had not yet reached skeletal maturity. Taphonomic and palaeoenvironmental data suggest that these phytosaurs were living in the marine lagoon in which they were preserved, providing the strongest evidence to date of marine adaptations in phytosaurs.
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Affiliation(s)
- Richard J Butler
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, UK
| | - Andrew S Jones
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, UK
| | - Eric Buffetaut
- Centre National de la Recherche Scientifique, UMR 8538, Laboratoire de Géologie de l’École Normale Supérieure, Paris Sciences et Lettres, Research University, Paris, France
| | - Gerhard W Mandl
- Department of Sedimentary Geology, Geological Survey of Austria, Vienna, Austria
| | - Torsten M Scheyer
- Universität Zürich, Paläontologisches Institut und Museum, Zürich, Switzerland
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Voeten DFAE, Reich T, Araújo R, Scheyer TM. Synchrotron microtomography of a Nothosaurus marchicus skull informs on nothosaurian physiology and neurosensory adaptations in early Sauropterygia. PLoS One 2018; 13:e0188509. [PMID: 29298295 PMCID: PMC5751976 DOI: 10.1371/journal.pone.0188509] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 11/08/2017] [Indexed: 02/06/2023] Open
Abstract
Nothosaurs form a subclade of the secondarily marine Sauropterygia that was well represented in late Early to early Late Triassic marine ecosystems. Here we present and discuss the internal skull anatomy of the small piscivorous nothosaur Nothosaurus marchicus from coastal to shallow marine Lower Muschelkalk deposits (Anisian) of Winterswijk, The Netherlands, which represents the oldest sauropterygian endocast visualized to date. The cranial endocast is only partially encapsulated by ossified braincase elements. Cranial flattening and lateral constriction by hypertrophied temporal musculature grant the brain a straight, tubular geometry that lacks particularly well-developed cerebral lobes but does potentially involve distinguishable optic lobes, suggesting vision may have represented an important sense during life. Despite large orbit size, the circuitous muscular pathway linking the basisphenoidal and orbital regions indicates poor oculomotor performance. This suggests a rather fixed ocular orientation, although eye placement and neck manoeuvrability could have enabled binocular if not stereoscopic vision. The proportionally large dorsal projection of the braincase endocast towards the well-developed pineal foramen advocates substantial dependence on the corresponding pineal system in vivo. Structures corroborating keen olfactory or acoustic senses were not identified. The likely atrophied vomeronasal organ argues against the presence of a forked tongue in Nothosaurus, and the relative positioning of external and internal nares contrasts respiratory configurations proposed for pistosauroid sauropterygians. The antorbital domain furthermore accommodates a putative rostral sensory plexus and pronounced lateral nasal glands that were likely exapted as salt glands. Previously proposed nothosaurian 'foramina eustachii' arose from architectural constraints on braincase development rather than representing functional foramina. Several modifications to brain shape and accessory organs were achieved through heterochronic development of the cranium, particularly the braincase. In summary, the cranium of Nothosaurus marchicus reflects important physiological and neurosensory adaptations that enabled the group's explosive invasion of shallow marine habitats in the late Early Triassic.
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Affiliation(s)
- Dennis F. A. E. Voeten
- European Synchrotron Radiation Facility, Grenoble, France
- Department of Zoology and Laboratory of Ornithology, Palacký University, Olomouc, Czech Republic
| | - Tobias Reich
- University of Zurich, Palaeontological Institute and Museum, Zurich, Switzerland
| | - Ricardo Araújo
- Institute for Plasma Research and Nuclear Fusion, Technical University of Lisbon, Lisbon, Portugal
- Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Berlin, Germany
- Institute of Evolutionary Sciences, University of Montpellier 2, Montpellier, France
| | - Torsten M. Scheyer
- University of Zurich, Palaeontological Institute and Museum, Zurich, Switzerland
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Scheyer TM, Delfino M, Klein N, Bunbury N, Fleischer-Dogley F, Hansen DM. Trophic interactions between larger crocodylians and giant tortoises on Aldabra Atoll, Western Indian Ocean, during the Late Pleistocene. R Soc Open Sci 2018; 5:171800. [PMID: 29410873 PMCID: PMC5792950 DOI: 10.1098/rsos.171800] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 12/06/2017] [Indexed: 06/08/2023]
Abstract
Today, the UNESCO World Heritage Site of Aldabra Atoll is home to about 100 000 giant tortoises, Aldabrachelys gigantea, whose fossil record goes back to the Late Pleistocene. New Late Pleistocene fossils (age ca. 90-125 000 years) from the atoll revealed some appendicular bones and numerous shell fragments of giant tortoises and cranial and postcranial elements of crocodylians. Several tortoise bones show circular holes, pits and scratch marks that are interpreted as bite marks of crocodylians. The presence of a Late Pleistocene crocodylian species, Aldabrachampsus dilophus, has been known for some time, but the recently found crocodylian remains presented herein are distinctly larger than those previously described. This indicates the presence of at least some larger crocodylians, either of the same or of a different species, on the atoll. These larger crocodylians, likely the apex predators in the Aldabra ecosystem at the time, were well capable of inflicting damage on even very large giant tortoises. We thus propose an extinct predator-prey interaction between crocodylians and giant tortoises during the Late Pleistocene, when both groups were living sympatrically on Aldabra, and we discuss scenarios for the crocodylians directly attacking the tortoises or scavenging on recently deceased animals.
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Affiliation(s)
- Torsten M. Scheyer
- University of Zurich, Palaeontological Institute and Museum, Karl Schmid-Strasse 4, 8006 Zurich, Switzerland
| | - Massimo Delfino
- Dipartimento di Scienze della Terra, Università di Torino, Via Valperga Caluso 35, I-10125 Torino, Italy
- Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona, Edifici ICTA-ICP, Carrer de les Columnes s/n, Campus de la UAB, Cerdanyola del Vallès, Barcelona 08193, Spain
| | - Nicole Klein
- Steinmann Institut für Geologie, Paläontologie und Mineralogie, Universität Bonn, Nussallee 8, 53115 Bonn, Germany
| | - Nancy Bunbury
- Seychelles Islands Foundation, PO Box 853, Victoria, Mahé, Seychelles
| | | | - Dennis M. Hansen
- Zoological Museum and the Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
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Foth C, Fernandez Blanco MV, Bona P, Scheyer TM. Cranial shape variation in jacarean caimanines (Crocodylia, Alligatoroidea) and its implications in the taxonomic status of extinct species: The case ofMelanosuchus fisheri. J Morphol 2017; 279:259-273. [DOI: 10.1002/jmor.20769] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 10/09/2017] [Accepted: 10/11/2017] [Indexed: 11/05/2022]
Affiliation(s)
- Christian Foth
- Department of Geosciences; University of Fribourg/Freiburg, Chemin du Musée 6; Fribourg CH-1700 Switzerland
- Staatliches Museum für Naturkunde, Rosenstein 1; Stuttgart D-70191 Germany
| | - María Victoria Fernandez Blanco
- División Paleontología Vertebrados, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Museo de La Plata-Universidad Nacional de La Plata. Paseo del Bosque s/n. 1900, La Plata, Buenos Aires, Argentina
| | - Paula Bona
- División Paleontología Vertebrados, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Museo de La Plata-Universidad Nacional de La Plata. Paseo del Bosque s/n. 1900, La Plata, Buenos Aires, Argentina
| | - Torsten M. Scheyer
- Paläontologisches Institut und Museum, Universität Zürich, Karl Schmid-Strasse 4; Zürich CH-8006 Switzerland
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Scheyer TM, Neenan JM, Bodogan T, Furrer H, Obrist C, Plamondon M. A new, exceptionally preserved juvenile specimen of Eusaurosphargis dalsassoi (Diapsida) and implications for Mesozoic marine diapsid phylogeny. Sci Rep 2017; 7:4406. [PMID: 28667331 PMCID: PMC5493663 DOI: 10.1038/s41598-017-04514-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 05/16/2017] [Indexed: 11/17/2022] Open
Abstract
Recently it was suggested that the phylogenetic clustering of Mesozoic marine reptile lineages, such as thalattosaurs, the very successful fish-shaped ichthyosaurs and sauropterygians (including plesiosaurs), among others, in a so-called 'superclade' is an artefact linked to convergent evolution of morphological characters associated with a shared marine lifestyle. Accordingly, partial 'un-scoring' of the problematic phylogenetic characters was proposed. Here we report a new, exceptionally preserved and mostly articulated juvenile skeleton of the diapsid reptile, Eusaurosphargis dalsassoi, a species previously recovered within the marine reptile 'superclade', for which we now provide a revised diagnosis. Using micro-computed tomography, we show that besides having a deep skull with a short and broad rostrum, the most outstanding feature of the new specimen is extensive, complex body armour, mostly preserved in situ, along its vertebrae, ribs, and forelimbs, as well as a row of flat, keeled ventrolateral osteoderms associated with the gastralia. As a whole, the anatomical features support an essentially terrestrial lifestyle of the animal. A review of the proposed partial character 'un-scoring' using three published data matrices indicate that this approach is flawed and should be avoided, and that within the marine reptile 'superclade' E. dalsassoi potentially is the sister taxon of Sauropterygia.
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Affiliation(s)
- Torsten M Scheyer
- Universität Zürich, Paläontologisches Institut und Museum, Karl Schmid-Strasse 4, CH-8006, Zurich, Switzerland.
| | - James M Neenan
- Oxford University Museum of Natural History, Parks Road, Oxford, OX1 3PW, UK
| | - Timea Bodogan
- Universität Zürich, Paläontologisches Institut und Museum, Karl Schmid-Strasse 4, CH-8006, Zurich, Switzerland
| | - Heinz Furrer
- Universität Zürich, Paläontologisches Institut und Museum, Karl Schmid-Strasse 4, CH-8006, Zurich, Switzerland
| | | | - Mathieu Plamondon
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Center for X-ray Analytics, Überlandstrasse 129, CH-8600, Dübendorf, Switzerland
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Mautner AK, Latimer AE, Fritz U, Scheyer TM. An updated description of the osteology of the pancake tortoiseMalacochersus tornieri(Testudines: Testudinidae) with special focus on intraspecific variation. J Morphol 2017; 278:321-333. [DOI: 10.1002/jmor.20640] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 11/23/2016] [Accepted: 12/04/2016] [Indexed: 01/05/2023]
Affiliation(s)
- Anna-Katharina Mautner
- University of Zurich, Palaeontological Institute and Museum; Karl Schmid-Strasse 4 Zurich CH-8006 Switzerland
| | - Ashley E. Latimer
- University of Zurich, Palaeontological Institute and Museum; Karl Schmid-Strasse 4 Zurich CH-8006 Switzerland
| | - Uwe Fritz
- Museum of Zoology (Museum für Tierkunde); A. B. Meyer Building Dresden D-01109 Germany
| | - Torsten M. Scheyer
- University of Zurich, Palaeontological Institute and Museum; Karl Schmid-Strasse 4 Zurich CH-8006 Switzerland
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Rössner GE, Costeur L, Scheyer TM. What is a deer and what is an antler? Mamm Biol 2016. [DOI: 10.1016/j.mambio.2016.07.042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Klein N, Sander PM, Krahl A, Scheyer TM, Houssaye A. Diverse Aquatic Adaptations in Nothosaurus spp. (Sauropterygia)-Inferences from Humeral Histology and Microanatomy. PLoS One 2016; 11:e0158448. [PMID: 27391607 PMCID: PMC4938232 DOI: 10.1371/journal.pone.0158448] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 06/16/2016] [Indexed: 11/19/2022] Open
Abstract
Mid-diaphyseal cortical bone tissue in humeri of Nothosaurus spp. consists of coarse parallel-fibered bone, finer and higher organized parallel-fibered bone, and lamellar bone. Vascular canals are mainly arranged longitudinally and radially in a dominantly radial system. Blood vessels are represented by simple vascular canals, incompletely lined primary osteons, and fully developed primary osteons. Nothosaurus spp. shows a variety of diaphyseal microanatomical patterns, ranging from thick to very thin-walled cortices. In the early Anisian (Lower Muschelkalk), small- and large-bodied Nothosaurus spp. generally exhibit bone mass increase (BMI). In the middle to late Anisian (Middle Muschelkalk) small-bodied nothosaurs retain BMI whereas larger-bodied forms tend to show a decrease in bone mass (BMD). During the latest Anisian to early Ladinian (Upper Muschelkalk), small- and few large-bodied nothosaurs retain BMI, whereas the majority of large-bodied forms exhibit BMD. The stratigraphically youngest nothosaurs document five microanatomical categories, two of which are unique among marine amniotes: One consists of a very heterogeneously distributed spongy periosteal organization, the other of very thin-walled cortices. The functional significance of the two unique microanatomical specializations seen in large-bodied nothosaurs is the reduction of bone mass, which minimizes inertia of the limbs, and thus saves energy during locomotion. Transitions between the various microanatomical categories are rather gradual. Our results suggest that small-bodied Nothosaurus marchicus and other, not further assignable small-bodied nothosaurs seem to have been bound to near-shore, shallow marine environments throughout their evolution. Some large-bodied Nothosaurus spp. followed the same trend but others became more active swimmers and possibly inhabited open marine environments. The variety of microanatomical patterns may be related to taxonomic differences, developmental plasticity, and possibly sexual dimorphism. Humeral microanatomy documents the diversification of nothosaur species into different environments to avoid intraclade competition as well as competition with other marine reptiles. Nothosaur microanatomy indicates that knowledge of processes involved in secondary aquatic adaptation and their interaction are more complex than previously believed.
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Affiliation(s)
- Nicole Klein
- Staatliches Museum für Naturkunde Stuttgart, Rosenstein 1, 70191 Stuttgart, Germany
- * E-mail:
| | - P. Martin Sander
- Steinmann-Institute, Division of Paleontology, University of Bonn, Nußallee 8, 53115 Bonn, Germany
| | - Anna Krahl
- Biomechanics Research Group, Faculty of Mechanical Engineering, Ruhr-Universität Bochum, Universitätsstr. 150, 44801 Bochum, Germany
| | - Torsten M. Scheyer
- Palaeontological Institute and Museum, University of Zurich, Karl Schmid-Strasse 4, CH-8006 Zürich, Switzerland
| | - Alexandra Houssaye
- UMR 7179 CNRS/Muséum National d'Histoire Naturelle, Département Ecologie et Gestion de la Biodiversité, 57 rue Cuvier CP-55, 75000 Paris France
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Kolb C, Scheyer TM, Veitschegger K, Forasiepi AM, Amson E, Van der Geer AAE, Van den Hoek Ostende LW, Hayashi S, Sánchez-Villagra MR. Mammalian bone palaeohistology: a survey and new data with emphasis on island forms. PeerJ 2015; 3:e1358. [PMID: 26528418 PMCID: PMC4627922 DOI: 10.7717/peerj.1358] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 10/07/2015] [Indexed: 01/31/2023] Open
Abstract
The interest in mammalian palaeohistology has increased dramatically in the last two decades. Starting in 1849 via descriptive approaches, it has been demonstrated that bone tissue and vascularisation types correlate with several biological variables such as ontogenetic stage, growth rate, and ecology. Mammalian bone displays a large variety of bone tissues and vascularisation patterns reaching from lamellar or parallel-fibred to fibrolamellar or woven-fibred bone, depending on taxon and individual age. Here we systematically review the knowledge and methods on cynodont and mammalian bone microstructure as well as palaeohistology and discuss potential future research fields and techniques. We present new data on the bone microstructure of two extant marsupial species and of several extinct continental and island placental mammals. Extant marsupials display mainly parallel-fibred primary bone with radial and oblique but mainly longitudinal vascular canals. Three juvenile specimens of the dwarf island hippopotamid Hippopotamus minor from the Late Pleistocene of Cyprus show reticular to plexiform fibrolamellar bone. The island murid Mikrotia magna from the Late Miocene of Gargano, Italy displays parallel-fibred primary bone with reticular vascularisation and strong remodelling in the middle part of the cortex. Leithia sp., the dormouse from the Pleistocene of Sicily, is characterised by a primary bone cortex consisting of lamellar bone and a high amount of compact coarse cancellous bone. The bone cortex of the fossil continental lagomorph Prolagus oeningensis and three fossil species of insular Prolagus displays mainly parallel-fibred primary bone and reticular, radial as well as longitudinal vascularisation. Typical for large mammals, secondary bone in the giant rhinocerotoid Paraceratherium sp. from the Late Oligocene of Turkey is represented by dense Haversian bone. The skeletochronological features of Sinomegaceros yabei, a large-sized deer from the Pleistocene of Japan closely related to Megaloceros, indicate a high growth rate. These examples and the synthesis of existing data show the potential of bone microstructure to reveal essential information on life history evolution. The bone tissue and the skeletochronological data of the sampled island species suggest the presence of various modes of bone histological modification and mammalian life history evolution on islands to depend on factors of island evolution such as island size, distance from mainland, climate, phylogeny, and time of evolution.
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Affiliation(s)
- Christian Kolb
- Paläontologisches Institut und Museum, Universität Zürich , Zürich , Switzerland
| | - Torsten M Scheyer
- Paläontologisches Institut und Museum, Universität Zürich , Zürich , Switzerland
| | - Kristof Veitschegger
- Paläontologisches Institut und Museum, Universität Zürich , Zürich , Switzerland
| | - Analia M Forasiepi
- Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales, Centro Científico y Tecnológico , Mendoza , Argentina
| | - Eli Amson
- Paläontologisches Institut und Museum, Universität Zürich , Zürich , Switzerland
| | - Alexandra A E Van der Geer
- Department of Geology, Naturalis Biodiversity Center , Leiden , The Netherlands ; Department of Historical Geology and Palaeontology, National and Kapodistrian University of Athens , Zografou , Greece
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Barrett PM, Butler RJ, Mundil R, Scheyer TM, Irmis RB, Sánchez-Villagra MR. A palaeoequatorial ornithischian and new constraints on early dinosaur diversification. Proc Biol Sci 2015; 281:20141147. [PMID: 25100698 DOI: 10.1098/rspb.2014.1147] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Current characterizations of early dinosaur evolution are incomplete: existing palaeobiological and phylogenetic scenarios are based on a fossil record dominated by saurischians and the implications of the early ornithischian record are often overlooked. Moreover, the timings of deep phylogenetic divergences within Dinosauria are poorly constrained owing to the absence of a rigorous chronostratigraphical framework for key Late Triassic-Early Jurassic localities. A new dinosaur from the earliest Jurassic of the Venezuelan Andes is the first basal ornithischian recovered from terrestrial deposits directly associated with a precise radioisotopic date and the first-named dinosaur from northern South America. It expands the early palaeogeographical range of Ornithischia to palaeoequatorial regions, an area sometimes thought to be devoid of early dinosaur taxa, and offers insights into early dinosaur growth rates, the evolution of sociality and the rapid tempo of the global dinosaur radiation following the end-Triassic mass extinction, helping to underscore the importance of the ornithischian record in broad-scale discussions of early dinosaur history.
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Affiliation(s)
- Paul M Barrett
- Department of Earth Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, UK
| | - Richard J Butler
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK GeoBio-Center, Ludwig-Maximilians-Universität München, Richard-Wagner-Straße 10, 80333 Munich, Germany
| | - Roland Mundil
- Berkeley Geochronology Center, 2455 Ridge Road, Berkeley, CA 94709, USA
| | - Torsten M Scheyer
- Paläontologisches Institut und Museum, Universität Zürich, Karl Schmid-Strasse 4, 8006 Zürich, Switzerland
| | - Randall B Irmis
- Natural History Museum of Utah, 301 Wakara Way, Salt Lake City, UT 84108-1214, USA Department of Geology and Geophysics, University of Utah, Salt Lake City, UT 84112-0102, USA
| | - Marcelo R Sánchez-Villagra
- Paläontologisches Institut und Museum, Universität Zürich, Karl Schmid-Strasse 4, 8006 Zürich, Switzerland
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Klein N, Neenan JM, Scheyer TM, Griebeler EM. Growth patterns and life-history strategies in Placodontia (Diapsida: Sauropterygia). R Soc Open Sci 2015; 2:140440. [PMID: 26587259 PMCID: PMC4632572 DOI: 10.1098/rsos.140440] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 06/11/2015] [Indexed: 06/05/2023]
Abstract
Placodontia is a clade of durophagous, near shore marine reptiles from Triassic sediments of modern-day Europe, Middle East and China. Although much is known about their primary anatomy and palaeoecology, relatively little has been published regarding their life history, i.e. ageing, maturation and growth. Here, growth records derived from long bone histological data of placodont individuals are described and modelled to assess placodont growth and life-history strategies. Growth modelling methods are used to confirm traits documented in the growth record (age at onset of sexual maturity, age when asymptotic length was achieved, age at death, maximum longevity) and also to estimate undocumented traits. Based on these growth models, generalized estimates of these traits are established for each taxon. Overall differences in bone tissue types and resulting growth curves indicate different growth patterns and life-history strategies between different taxa of Placodontia. Psephoderma and Paraplacodus grew with lamellar-zonal bone tissue type and show growth patterns as seen in modern reptiles. Placodontia indet. aff. Cyamodus and some Placodontia indet. show a unique combination of fibrolamellar bone tissue regularly stratified by growth marks, a pattern absent in modern sauropsids. The bone tissue type of Placodontia indet. aff. Cyamodus and Placodontia indet. indicates a significantly increased basal metabolic rate when compared with modern reptiles. Double lines of arrested growth, non-annual rest lines in annuli, and subcycles that stratify zones suggest high dependence of placodont growth on endogenous and exogenous factors. Histological and modelled differences within taxa point to high individual developmental plasticity but sexual dimorphism in growth patterns and the presence of different taxa in the sample cannot be ruled out.
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Affiliation(s)
- Nicole Klein
- State Museum of Natural History Stuttgart, Rosenstein 1, 70191 Stuttgart, Germany
| | - James M. Neenan
- Palaeontological Institute and Museum, University of Zurich, Karl Schmid-Strasse 4, 8006 Zürich, Switzerland
| | - Torsten M. Scheyer
- Palaeontological Institute and Museum, University of Zurich, Karl Schmid-Strasse 4, 8006 Zürich, Switzerland
| | - Eva Maria Griebeler
- Department of Ecology, Zoological Institute, University of Mainz, 55099 Mainz, Germany
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Neenan JM, Li C, Rieppel O, Scheyer TM. The cranial anatomy of Chinese placodonts and the phylogeny of Placodontia (Diapsida: Sauropterygia). Zool J Linn Soc 2015. [DOI: 10.1111/zoj.12277] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- James M. Neenan
- Palaeontological Institute and Museum; University of Zurich; Karl Schmid-Strasse 4 8006 Zurich Switzerland
- The Function, Evolution and Anatomy Research (FEAR) Lab; School of Environmental and Rural Science; University of New England; Armidale NSW 2351 Australia
| | - Chun Li
- Institute of Vertebrate Paleontology and Paleoanthropology; Chinese Academy of Sciences; Beijing 100044 China
| | - Olivier Rieppel
- The Field Museum; 1400 South Lake Shore Drive Chicago IL 60605-2496 USA
| | - Torsten M. Scheyer
- Palaeontological Institute and Museum; University of Zurich; Karl Schmid-Strasse 4 8006 Zurich Switzerland
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Abstract
Placodontia, an enigmatic group of durophagous and in part heavily armoured animals, were members of Sauropterygia, the most diverse and successful group of Mesozoic marine reptiles. Microanatomy and histology of long bones of several armoured and non-armoured Placodontia were studied, covering most of their taxonomic breadth, to elucidate the paleoecology, physiology, and lifestyle of its members. Results reveal an unexpected and not phylogenetically or stratigraphically related disparity of microanatomical and histological features for the group. The non-armoured Paraplacodus and the heavily armoured Psephoderma grew with lamellar-zonal bone tissue type, which is typical for modern sauropsids. In the former, the tissue is nearly avascular surrounding a compacted medullary region, whereas in the latter, the lamellar-zonal bone tissue is vascularized framing a large open medullary cavity and a perimedullary region. Armoured Henodus and Placodontia indet. aff. Cyamodus as well as non-armoured Placodus exhibit a reduced medullary cavity and grew with highly vascularized plexiform to radiating fibro-lamellar bone. Several long bones of Placodontia indet. show circumferential fibro-lamellar bone and can be distinguished into two groups on the basis of microanatomical features. In addition, all bones that grew with fibro-lamellar bone show locally primary spongeous-like architecture and had secondarily widened primary osteons throughout the cortex, resulting in a secondarily spongeous tissue. The highly vascularized fibro-lamellar bone of these Placodontia indicates growth rates comparable to that of open marine ichthyosaurs. Differences in microanatomy and bone histology as expressed by a principal component analysis, thus clearly indicate different paleoecologies, including differences in lifestyle and swimming modes and capabilities in Placodontia. This would have reduced competition in the shallow marine environments of the Tethys and might be a key to their success and diversity. A certain developmental plasticity among the studied placodonts is interpreted as response to different environmental conditions as is obvious from inter- and intraspecific histological variation. Most striking is the difference in life history strategy in armoured Psephoderma and non-armoured Paraplacodus when compared to armoured Henodus, Placodontia indet. aff. Cyamodus, non-armoured Placodus, and Placodontia indet. Bone tissue of Psephoderma and Paraplacodus indicates low growth rates and a low basal metabolic rate, as many modern sauropsids have such as the marine iguana, whereas the others grew with extremely fast
growth rates, more typical for birds and mammals, indicating an increased basal metabolic rate.
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Affiliation(s)
- Nicole Klein
- 1 Staatliches Museum für Naturkunde Stuttgart Rosenstein 1 70191 Stuttgart
- 5 E:mail:
| | - Alexandra Houssaye
- 2 UMR 7179 CNRS/Muséum National d’Histoire Naturelle Département Ecologie et Gestion de la Biodiversité 57 rue Cuvier CP-55 75000 Paris France
| | - James M. Neenan
- 3 Paläontologisches Institut und Museum Universität Zürich Karl Schmid-Strasse 4 CH-8006 Zurich Switzerland
- 4 The Function, Evolution and Anatomy Research (FEAR) Lab, School of Environmental and Rural Science University of New England Armidale NSW 2351 Australia
| | - Torsten M. Scheyer
- 3 Paläontologisches Institut und Museum Universität Zürich Karl Schmid-Strasse 4 CH-8006 Zurich Switzerland
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Kolb C, Scheyer TM, Lister AM, Azorit C, de Vos J, Schlingemann MAJ, Rössner GE, Monaghan NT, Sánchez-Villagra MR. Growth in fossil and extant deer and implications for body size and life history evolution. BMC Evol Biol 2015; 15:19. [PMID: 25887855 PMCID: PMC4332446 DOI: 10.1186/s12862-015-0295-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 01/27/2015] [Indexed: 12/13/2022] Open
Abstract
Background Body size variation within clades of mammals is widespread, but the developmental and life-history mechanisms by which this variation is achieved are poorly understood, especially in extinct forms. An illustrative case study is that of the dwarfed morphotypes of Candiacervus from the Pleistocene of Crete versus the giant deer Megaloceros giganteus, both in a clade together with Dama dama among extant species. Histological analyses of long bones and teeth in a phylogenetic context have been shown to provide reliable estimates of growth and life history patterns in extant and extinct mammals. Results Similarity of bone tissue types across the eight species examined indicates a comparable mode of growth in deer, with long bones mainly possessing primary plexiform fibrolamellar bone. Low absolute growth rates characterize dwarf Candiacervus sp. II and C. ropalophorus compared to Megaloceros giganteus displaying high rates, whereas Dama dama is characterized by intermediate to low growth rates. The lowest recorded rates are those of the Miocene small stem cervid Procervulus praelucidus. Skeletal maturity estimates indicate late attainment in sampled Candiacervus and Procervulus praelucidus. Tooth cementum analysis of first molars of two senile Megaloceros giganteus specimens revealed ages of 16 and 19 years whereas two old dwarf Candiacervus specimens gave ages of 12 and 18 years. Conclusions There is a rich histological record of growth across deer species recorded in long bones and teeth, which can be used to understand ontogenetic patterns within species and phylogenetic ones across species. Growth rates sensu Sander & Tückmantel plotted against the anteroposterior bone diameter as a proxy for body mass indicate three groups: one with high growth rates including Megaloceros, Cervus, Alces, and Dama; an intermediate group with Capreolus and Muntiacus; and a group showing low growth rates, including dwarf Candiacervus and Procervulus. Dwarf Candiacervus, in an allometric context, show an extended lifespan compared to other deer of similar body size such as Mazama which has a maximum longevity of 12 years in the wild. Comparison with other clades of mammals reveals that changes in size and life history in evolution have occurred in parallel, with various modes of skeletal tissue modification. Electronic supplementary material The online version of this article (doi:10.1186/s12862-015-0295-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Christian Kolb
- Paläontologisches Institut und Museum der Universität Zürich, Karl Schmid-Strasse 4, CH-8006, Zürich, Switzerland.
| | - Torsten M Scheyer
- Paläontologisches Institut und Museum der Universität Zürich, Karl Schmid-Strasse 4, CH-8006, Zürich, Switzerland.
| | - Adrian M Lister
- Department of Earth Sciences, The Natural History Museum, Cromwell Road, London, SW7 5BD, UK.
| | - Concepcion Azorit
- Department of Animal and Vegetal Biology and Ecology, Faculty of Experimental Sciences, University of Jaén, Jaén, 23071, Spain.
| | - John de Vos
- Naturalis Biodiversity Center, Postbus 9517, 2300, RA Leiden, The Netherlands.
| | - Margaretha A J Schlingemann
- Department of Integrative Zoology, IBL, Leiden University, Sylviusweg 72, Postbus 9505, 2300, RA Leiden, The Netherlands.
| | - Gertrud E Rössner
- Bayerische Staatssammlung für Paläontologie und Geologie, Richard-Wagner-Strasse 10, D-80333, München, Germany.
| | - Nigel T Monaghan
- National Museum of Ireland-Natural History, Merrion Street, Dublin 2, Ireland.
| | - Marcelo R Sánchez-Villagra
- Paläontologisches Institut und Museum der Universität Zürich, Karl Schmid-Strasse 4, CH-8006, Zürich, Switzerland.
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Cerda IA, Desojo JB, Trotteyn MJ, Scheyer TM. Osteoderm histology of Proterochampsia and Doswelliidae (Reptilia: Archosauriformes) and their evolutionary and paleobiological implications. J Morphol 2015; 276:385-402. [DOI: 10.1002/jmor.20348] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 10/05/2014] [Accepted: 11/18/2014] [Indexed: 11/06/2022]
Affiliation(s)
- Ignacio A. Cerda
- Conicet: Rivadavia 1917; Buenos Aires 1000-1499 Argentina
- Instituto de Investigación en Paleobiología y Geología; Universidad Nacional de Río Negro, Museo Carlos Ameghino, Belgrano 1700, Paraje Pichi Ruca (predio Marabunta); 8300 Cipolletti Río Negro Argentina
| | - Julia B. Desojo
- Conicet: Rivadavia 1917; Buenos Aires 1000-1499 Argentina
- Sección Paleontología Vertebrados; Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”, Ángel Gallardo 470 C1405DJR; Buenos Aires Argentina
| | - María J. Trotteyn
- Conicet: Rivadavia 1917; Buenos Aires 1000-1499 Argentina
- INGEO. Instituto de Geología, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de San Juan. Ignacio de la Rosa 590 (oeste), Complejo Universitario Islas Malvinas; San Juan Argentina CP 5400
| | - Torsten M. Scheyer
- Paläontologisches Institut und Museum der Universität Zürich; Karl Schmid-Strasse 4, CH-8006 Zürich Switzerland
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Lyson TR, Schachner ER, Botha-Brink J, Scheyer TM, Lambertz M, Bever GS, Rubidge BS, de Queiroz K. Origin of the unique ventilatory apparatus of turtles. Nat Commun 2014; 5:5211. [PMID: 25376734 DOI: 10.1038/ncomms6211] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Accepted: 09/10/2014] [Indexed: 11/09/2022] Open
Abstract
The turtle body plan differs markedly from that of other vertebrates and serves as a model system for studying structural and developmental evolution. Incorporation of the ribs into the turtle shell negates the costal movements that effect lung ventilation in other air-breathing amniotes. Instead, turtles have a unique abdominal-muscle-based ventilatory apparatus whose evolutionary origins have remained mysterious. Here we show through broadly comparative anatomical and histological analyses that an early member of the turtle stem lineage has several turtle-specific ventilation characters: rigid ribcage, inferred loss of intercostal muscles and osteological correlates of the primary expiratory muscle. Our results suggest that the ventilation mechanism of turtles evolved through a division of labour between the ribs and muscles of the trunk in which the abdominal muscles took on the primary ventilatory function, whereas the broadened ribs became the primary means of stabilizing the trunk. These changes occurred approximately 50 million years before the evolution of the fully ossified shell.
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Affiliation(s)
- Tyler R Lyson
- 1] Department of Earth Sciences, Denver Museum of Nature and Science, Denver, Colorado 80205, USA [2] Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington DC 20560, USA [3] Evolutionary Studies Institute, University of the Witwatersrand, PO Wits 2050, Johannesburg, South Africa
| | - Emma R Schachner
- 1] Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana 70803, USA [2] Department of Biology, University of Utah, Salt Lake City, Utah 84112, USA
| | - Jennifer Botha-Brink
- 1] Karoo Palaeontology, National Museum, Box 266, Bloemfontein 9300, South Africa [2] Department of Zoology and Entomology, University of the Free State, Bloemfontein 9300, South Africa
| | - Torsten M Scheyer
- Paläontologisches Institut und Museum, Universität Zürich, Karl Schmid-Strasse 4, 8006 Zürich, Switzerland
| | - Markus Lambertz
- Institut für Zoologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Poppelsdorfer Schloss, 53115 Bonn, Germany
| | - G S Bever
- 1] Evolutionary Studies Institute, University of the Witwatersrand, PO Wits 2050, Johannesburg, South Africa [2] New York Institute of Technology, College of Osteopathic Medicine, Old Westbury, New York 11568, USA [3] Division of Paleontology, American Museum of Natural History, New York, New York 10024, USA
| | - Bruce S Rubidge
- Evolutionary Studies Institute, University of the Witwatersrand, PO Wits 2050, Johannesburg, South Africa
| | - Kevin de Queiroz
- Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington DC 20560, USA
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