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Bishop PJ, Pierce SE. The fossil record of appendicular muscle evolution in Synapsida on the line to mammals: Part I-Forelimb. Anat Rec (Hoboken) 2024; 307:1764-1825. [PMID: 37726984 DOI: 10.1002/ar.25312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 07/15/2023] [Accepted: 08/08/2023] [Indexed: 09/21/2023]
Abstract
This paper is the first in a two-part series that charts the evolution of appendicular musculature along the mammalian stem lineage, drawing upon the exceptional fossil record of extinct synapsids. Here, attention is focused on muscles of the forelimb. Understanding forelimb muscular anatomy in extinct synapsids, and how this changed on the line to mammals, can provide important perspective for interpreting skeletal and functional evolution in this lineage, and how the diversity of forelimb functions in extant mammals arose. This study surveyed the osteological evidence for muscular attachments in extinct mammalian and nonmammalian synapsids, two extinct amniote outgroups, and a large selection of extant mammals, saurians, and salamanders. Observations were integrated into an explicit phylogenetic framework, comprising 73 character-state complexes covering all muscles crossing the shoulder, elbow, and wrist joints. These were coded for 33 operational taxonomic units spanning >330 Ma of tetrapod evolution, and ancestral state reconstruction was used to evaluate the sequence of muscular evolution along the stem lineage from Amniota to Theria. In addition to producing a comprehensive documentation of osteological evidence for muscle attachments in extinct synapsids, this work has clarified homology hypotheses across disparate taxa and helped resolve competing hypotheses of muscular anatomy in extinct species. The evolutionary history of mammalian forelimb musculature was a complex and nonlinear narrative, punctuated by multiple instances of convergence and concentrated phases of anatomical transformation. More broadly, this study highlights the great insight that a fossil-based perspective can provide for understanding the assembly of novel body plans.
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Affiliation(s)
- Peter J Bishop
- Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
- Geosciences Program, Queensland Museum, Brisbane, Queensland, Australia
| | - Stephanie E Pierce
- Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
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2
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Beeston SL, Poropat SF, Mannion PD, Pentland AH, Enchelmaier MJ, Sloan T, Elliott DA. Reappraisal of sauropod dinosaur diversity in the Upper Cretaceous Winton Formation of Queensland, Australia, through 3D digitisation and description of new specimens. PeerJ 2024; 12:e17180. [PMID: 38618562 PMCID: PMC11011616 DOI: 10.7717/peerj.17180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 03/11/2024] [Indexed: 04/16/2024] Open
Abstract
Skeletal remains of sauropod dinosaurs have been known from Australia for over 100 years. Unfortunately, the classification of the majority of these specimens to species level has historically been impeded by their incompleteness. This has begun to change in the last 15 years, primarily through the discovery and description of several partial skeletons from the Cenomanian-lower Turonian (lower Upper Cretaceous) Winton Formation in central Queensland, with four species erected to date: Australotitan cooperensis, Diamantinasaurus matildae, Savannasaurus elliottorum, and Wintonotitan wattsi. The first three of these appear to form a clade (Diamantinasauria) of early diverging titanosaurs (or close relatives of titanosaurs), whereas Wintonotitan wattsi is typically recovered as a distantly related non-titanosaurian somphospondylan. Through the use of 3D scanning, we digitised numerous specimens of Winton Formation sauropods, facilitating enhanced comparison between type and referred specimens, and heretofore undescribed specimens. We present new anatomical information on the holotype specimen of Diamantinasaurus matildae, and describe new remains pertaining to twelve sauropod individuals. Firsthand observations and digital analysis enabled previously proposed autapomorphic features of all four named Winton Formation sauropod species to be identified in the newly described specimens, with some specimens exhibiting putative autapomorphies of more than one species, prompting a reassessment of their taxonomic validity. Supported by a specimen-level phylogenetic analysis, we suggest that Australotitan cooperensis is probably a junior synonym of Diamantinasaurus matildae, but conservatively regard it herein as an indeterminate diamantinasaurian, meaning that the Winton Formation sauropod fauna now comprises three (rather than four) valid diamantinasaurian species: Diamantinasaurus matildae, Savannasaurus elliottorum, and Wintonotitan wattsi, with the latter robustly supported as a member of the clade for the first time. We refer some of the newly described specimens to these three species and provide revised diagnoses, with some previously proposed autapomorphies now regarded as diamantinasaurian synapomorphies. Our newly presented anatomical data and critical reappraisal of the Winton Formation sauropods facilitates a more comprehensive understanding of the mid-Cretaceous sauropod palaeobiota of central Queensland.
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Affiliation(s)
- Samantha L. Beeston
- Department of Earth Sciences, University College London, University of London, London, United Kingdom
- Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, Victoria, Australia
- Australian Age of Dinosaurs Museum of Natural History, Winton, Queensland, Australia
| | - Stephen F. Poropat
- Western Australian Organic and Isotope Geochemistry Centre, School of Earth and Planetary Science, Curtin University of Technology, Bentley, Western Australia, Australia
| | - Philip D. Mannion
- Department of Earth Sciences, University College London, University of London, London, United Kingdom
| | - Adele H. Pentland
- Australian Age of Dinosaurs Museum of Natural History, Winton, Queensland, Australia
- Western Australian Organic and Isotope Geochemistry Centre, School of Earth and Planetary Science, Curtin University of Technology, Bentley, Western Australia, Australia
| | | | - Trish Sloan
- Australian Age of Dinosaurs Museum of Natural History, Winton, Queensland, Australia
| | - David A. Elliott
- Australian Age of Dinosaurs Museum of Natural History, Winton, Queensland, Australia
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Lacerda MBS, Bittencourt JS, Hutchinson JR. Reconstruction of the pelvic girdle and hindlimb musculature of the early tetanurans Piatnitzkysauridae (Theropoda, Megalosauroidea). J Anat 2024; 244:557-593. [PMID: 38037880 PMCID: PMC10941590 DOI: 10.1111/joa.13983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 11/10/2023] [Accepted: 11/15/2023] [Indexed: 12/02/2023] Open
Abstract
Piatnitzkysauridae were Jurassic theropods that represented the earliest diverging branch of Megalosauroidea, being one of the earliest lineages to have evolved moderate body size. This clade's typical body size and some unusual anatomical features raise questions about locomotor function and specializations to aid in body support; and other palaeobiological issues. Biomechanical models and simulations can illuminate how extinct animals may have moved, but require anatomical data as inputs. With a phylogenetic context, osteological evidence, and neontological data on anatomy, it is possible to infer the musculature of extinct taxa. Here, we reconstructed the hindlimb musculature of Piatnitzkysauridae (Condorraptor, Marshosaurus, and Piatnitzkysaurus). We chose this clade for future usage in biomechanics, for comparisons with myological reconstructions of other theropods, and for the resulting evolutionary implications of our reconstructions; differential preservation affects these inferences, so we discuss these issues as well. We considered 32 muscles in total: for Piatnitzkysaurus, the attachments of 29 muscles could be inferred based on the osteological correlates; meanwhile, in Condorraptor and Marshosaurus, we respectively inferred 21 and 12 muscles. We found great anatomical similarity within Piatnitzkysauridae, but differences such as the origin of M. ambiens and size of M. caudofemoralis brevis are present. Similarities were evident with Aves, such as the division of the M. iliofemoralis externus and M. iliotrochantericus caudalis and a broad depression for the M. gastrocnemius pars medialis origin on the cnemial crest. Nevertheless, we infer plesiomorphic features such as the origins of M. puboischiofemoralis internus 1 around the "cuppedicus" fossa and M. ischiotrochantericus medially on the ischium. As the first attempt to reconstruct muscles in early tetanurans, our study allows a more complete understanding of myological evolution in theropod pelvic appendages.
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Affiliation(s)
- Mauro B. S. Lacerda
- Structure and Motion Laboratory, Department of Comparative Biomedical SciencesThe Royal Veterinary CollegeHatfieldUK
- Pós‐Graduação em ZoologiaInstituto de Ciências Biológicas, Universidade Federal de Minas GeraisBelo HorizonteBrazil
| | - Jonathas S. Bittencourt
- Departamento de GeologiaInstituto de Geociências, Universidade Federal de Minas GeraisBelo HorizonteBrazil
| | - John R. Hutchinson
- Structure and Motion Laboratory, Department of Comparative Biomedical SciencesThe Royal Veterinary CollegeHatfieldUK
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4
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Sciscio L, Bordy EM, Lockley MG, Abrahams M. Basal sauropodomorph locomotion: ichnological lessons from the Late Triassic trackways of bipeds and quadrupeds (Elliot Formation, main Karoo Basin). PeerJ 2023; 11:e15970. [PMID: 37790620 PMCID: PMC10542822 DOI: 10.7717/peerj.15970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 08/06/2023] [Indexed: 10/05/2023] Open
Abstract
Using modern ichnological and stratigraphic tools, we reinvestigate two iconic sauropodomorph-attributed tetradactyl ichnogenera, Pseudotetrasauropus and Tetrasauropus, and their stratigraphic occurrences in the middle Upper Triassic of Lesotho. These tracks have been reaffirmed and are stratigraphically well-constrained to the lower Elliot Formation (Stormberg Group, Karoo Basin) with a maximum depositional age range of <219-209 Ma (Norian). This represents the earliest record of basal sauropodomorph trackways in Gondwana, if not globally. Track and trackway morphology, the sedimentary context of the tracks, and unique features (e.g., drag traces) have enabled us to discuss the likely limb postures and gaits of the trackmakers. Pseudotetrasauropus has bipedal (P. bipedoida) and quadrupedal (P. jaquesi) trackway states, with the oldest quadrupedal Pseudotetrasauropus track and trackway parameters suggestive of a columnar, graviportal limb posture in the trackmaker. Moreover, an irregularity in the intermanus distance and manus orientation and morphology, in combination with drag traces, is indicative of a non-uniform locomotory suite or facultative quadrupedality. Contrastingly, Tetrasauropus, the youngest trackway, has distinctive medially deflected, robust pedal and manual claw traces and a wide and uniform intermanus distance relative to the interpedal. These traits suggest a quadrupedal trackmaker with clawed and fleshy feet and forelimbs held in a wide, flexed posture. Altogether, these trackways pinpoint the start of the southern African ichnological record of basal sauropodomorphs with bipedal and quadrupedal locomotory habits to, at least, c. 215 Ma in the middle Late Triassic.
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Affiliation(s)
- Lara Sciscio
- Department of Geoscience, University of Fribourg, Fribourg, Switzerland
- Department of Geological Sciences, University of Cape Town, Cape Town, South Africa
- JURASSICA Museum, Porrentruy, Jura, Switzerland
| | - Emese M. Bordy
- Department of Geological Sciences, University of Cape Town, Cape Town, South Africa
| | - Martin G. Lockley
- Dinosaur Trackers Research Group, University of Colorado, Denver, Colorado, United States of America
| | - Miengah Abrahams
- Department of Geological Sciences, University of Cape Town, Cape Town, South Africa
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5
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Moore BRS, Roloson MJ, Currie PJ, Ryan MJ, Patterson RT, Mallon JC. The appendicular myology of Stegoceras validum (Ornithischia: Pachycephalosauridae) and implications for the head-butting hypothesis. PLoS One 2022; 17:e0268144. [PMID: 36048811 PMCID: PMC9436104 DOI: 10.1371/journal.pone.0268144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 04/22/2022] [Indexed: 11/19/2022] Open
Abstract
In this study, we use an exceptional skeleton of the pachycephalosaur Stegoceras validum (UALVP 2) to inform a comprehensive appendicular muscle reconstruction of the animal, with the goal of better understanding the functional morphology of the pachycephalosaur postcranial skeleton. We find that S. validum possessed a conservative forelimb musculature, particularly in comparison to early saurischian bipeds. By contrast, the pelvic and hind limb musculature are more derived, reflecting peculiarities of the underlying skeletal anatomy. The iliotibialis, ischiocaudalis, and caudofemoralis muscles have enlarged attachment sites and the caudofemoralis has greater leverage owing to the distal displacement of the fourth trochanter along the femur. These larger muscles, in combination with the wide pelvis and stout hind limbs, produced a stronger, more stable pelvic structure that would have proved advantageous during hypothesized intraspecific head-butting contests. The pelvis may have been further stabilized by enlarged sacroiliac ligaments, which stemmed from the unique medial iliac flange of the pachycephalosaurs. Although the pubis of UALVP 2 is not preserved, the pubes of other pachycephalosaurs are highly reduced. The puboischiofemoralis musculature was likely also reduced accordingly, and compensated for by the aforementioned improved pelvic musculature.
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Affiliation(s)
- Bryan R. S. Moore
- Ottawa Carleton Geoscience Center and Department of Earth Sciences, Carleton University, Ottawa, Ontario, Canada
- * E-mail:
| | - Mathew J. Roloson
- Ottawa Carleton Geoscience Center and Department of Earth Sciences, Carleton University, Ottawa, Ontario, Canada
| | - Philip J. Currie
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Michael J. Ryan
- Ottawa Carleton Geoscience Center and Department of Earth Sciences, Carleton University, Ottawa, Ontario, Canada
- Beaty Centre for Species Discovery and Palaeobiology section, Canadian Museum of Nature, Ottawa, Ontario, Canada
| | - R. Timothy Patterson
- Ottawa Carleton Geoscience Center and Department of Earth Sciences, Carleton University, Ottawa, Ontario, Canada
| | - Jordan C. Mallon
- Ottawa Carleton Geoscience Center and Department of Earth Sciences, Carleton University, Ottawa, Ontario, Canada
- Beaty Centre for Species Discovery and Palaeobiology section, Canadian Museum of Nature, Ottawa, Ontario, Canada
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Lefebvre R, Houssaye A, Mallison H, Cornette R, Allain R. A path to gigantism: Three‐dimensional study of the sauropodomorph limb long bone shape variation in the context of the emergence of the sauropod bauplan. J Anat 2022; 241:297-336. [PMID: 35249216 PMCID: PMC9296025 DOI: 10.1111/joa.13646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 02/09/2022] [Accepted: 02/15/2022] [Indexed: 11/30/2022] Open
Abstract
Sauropodomorph dinosaurs include the largest terrestrial animals that ever lived on Earth. The early representatives of this clade were, however, relatively small and partially to totally bipedal, conversely to the gigantic and quadrupedal sauropods. Although the sauropod bauplan is well defined, notably by the acquisition of columnar limbs, the evolutionary sequence leading to its emergence remains debated. Here, we aim to tackle this evolutionary episode by investigating shape variation in the six limb long bones for the first time using three‐dimensional geometric morphometrics. The morphological features of the forelimb zeugopod bones related to the sauropod bauplan tend to appear abruptly, whereas the pattern is more gradual for the hindlimb zeugopod bones. The stylopod bones tend to show the same pattern as their respective zeugopods. The abrupt emergence of the sauropod forelimb questions the locomotor abilities of non‐sauropodan sauropodomorphs inferred as quadrupeds. Features characterizing sauropods tend to corroborate a view of their locomotion mainly based on stylopod retraction. An allometric investigation of the shape variation in accordance with size highlight differences in hindlimb bone allometries between the sauropods and the non‐sauropodan sauropodomorphs. These differences notably correspond to an unexpected robustness decrease trend in the sauropod hindlimb zeugopod. In addition to forelimb bones that appear to be proportionally more gracile than in non‐sauropodan sauropodomorphs, sauropods may have relied on limb architecture and features related to the size increase, rather than general robustness, to deal with the role of weight‐bearing.
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Affiliation(s)
- Rémi Lefebvre
- Mécanismes Adaptatifs et Évolution, UMR 7179, MNHN, CNRS Muséum National d'Histoire Naturelle Paris France
| | - Alexandra Houssaye
- Mécanismes Adaptatifs et Évolution, UMR 7179, MNHN, CNRS Muséum National d'Histoire Naturelle Paris France
| | | | - Raphaël Cornette
- Institut de Systématique, Évolution, Biodiversité, UMR7205, MNHN, CNRS, SU, EPHE, UA Muséum National d'Histoire Naturelle Paris France
| | - Ronan Allain
- Centre de Recherche en Paléontologie – Paris, UMR 7207, MNHN, CNRS, SU Muséum National d'Histoire Naturelle Paris France
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8
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Ballell A, Rayfield EJ, Benton MJ. Walking with early dinosaurs: appendicular myology of the Late Triassic sauropodomorph Thecodontosaurus antiquus. ROYAL SOCIETY OPEN SCIENCE 2022; 9:211356. [PMID: 35116154 PMCID: PMC8767213 DOI: 10.1098/rsos.211356] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 12/06/2021] [Indexed: 06/14/2023]
Abstract
Dinosaur evolution is marked by numerous independent shifts from bipedality to quadrupedality. Sauropodomorpha is one of the lineages that transitioned from small bipedal forms to graviportal quadrupeds, with an array of intermediate postural strategies evolving in non-sauropodan sauropodomorphs. This locomotor shift is reflected by multiple modifications of the appendicular skeleton, coupled with a drastic rearrangement of the limb musculature. Here, we describe the osteological correlates of appendicular muscle attachment of the Late Triassic sauropodomorph Thecodontosaurus antiquus from multiple well-preserved specimens and provide the first complete forelimb and hindlimb musculature reconstruction of an early-branching sauropodomorph. Comparisons with other sauropodomorphs and early dinosaurs reveal a unique combination of both plesiomorphic and derived musculoskeletal features. The diversity of appendicular osteological correlates among early dinosaurs and their relevance in muscle reconstruction are discussed. In line with previous evidence, aspects of the limb muscle arrangement, such as conspicuous correlates of lower limb extensors and flexors and low moment arms of hip extensors and flexors, suggest Thecodontosaurus was an agile biped. This reconstruction helps to elucidate the timing of important modifications of the appendicular musculature in the evolution of sauropodomorphs which facilitated the transition to quadrupedalism and contributed to their evolutionary success.
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Affiliation(s)
- Antonio Ballell
- School of Earth Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Emily J. Rayfield
- School of Earth Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Michael J. Benton
- School of Earth Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol BS8 1TQ, UK
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Hocknull SA, Wilkinson M, Lawrence RA, Konstantinov V, Mackenzie S, Mackenzie R. A new giant sauropod, Australotitan cooperensis gen. et sp. nov., from the mid-Cretaceous of Australia. PeerJ 2021; 9:e11317. [PMID: 34164230 PMCID: PMC8191491 DOI: 10.7717/peerj.11317] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 03/30/2021] [Indexed: 12/18/2022] Open
Abstract
A new giant sauropod, Australotitan cooperensis gen. et sp. nov., represents the first record of dinosaurs from the southern-central Winton Formation of the Eromanga Basin, Australia. We estimate the type locality to be 270–300 m from the base of the Winton Formation and compare this to the semi-contemporaneous sauropod taxa, Diamantinasaurus matildaeHocknull et al., 2009, Wintonotitan wattsiHocknull et al., 2009 and Savannasaurus elliottorumPoropat et al., 2016. The new titanosaurian is the largest dinosaur from Australia as represented by osteological remains and based on limb-size comparisons it reached a size similar to that of the giant titanosaurians from South America. Using 3-D surface scan models we compare features of the appendicular skeleton that differentiate Australotitan cooperensis gen. et sp. nov. as a new taxon. A key limitation to the study of sauropods is the inability to easily and directly compare specimens. Therefore, 3-D cybertypes have become a more standard way to undertake direct comparative assessments. Uncoloured, low resolution, and uncharacterized 3-D surface models can lead to misinterpretations, in particular identification of pre-, syn- and post-depositional distortion. We propose a method for identifying, documenting and illustrating these distortions directly onto the 3-D geometric surface of the models using a colour reference scheme. This new method is repeatable for researchers when observing and documenting specimens including taphonomic alterations and geometric differences. A detailed comparative and preliminary computational phylogenetic assessment supports a shared ancestry for all four Winton Formation taxa, albeit with limited statistical support. Palaeobiogeographical interpretations from these resultant phylogenetic hypotheses remain equivocal due to contrary Asian and South American relationships with the Australian taxa. Temporal and palaeoenvironmental differences between the northern and southern-central sauropod locations are considered to explain the taxonomic and morphological diversity of sauropods from the Winton Formation. Interpretations for this diversity are explored, including an eco-morphocline and/or chronocline across newly developed terrestrial environments as the basin fills.
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Affiliation(s)
- Scott A Hocknull
- Geosciences, Queensland Museum, Hendra, Brisbane City, Australia.,Biosciences, University of Melbourne, Melbourne, Victoria, Australia
| | | | | | | | - Stuart Mackenzie
- Eromanga Natural History Museum, Eromanga, Queensland, Australia
| | - Robyn Mackenzie
- Eromanga Natural History Museum, Eromanga, Queensland, Australia
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10
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Voegele KK, Ullmann PV, Lamanna MC, Lacovara KJ. Myological reconstruction of the pelvic girdle and hind limb of the giant titanosaurian sauropod dinosaur Dreadnoughtus schrani. J Anat 2021; 238:576-597. [PMID: 33084085 PMCID: PMC7855065 DOI: 10.1111/joa.13334] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 08/26/2020] [Accepted: 09/21/2020] [Indexed: 01/21/2023] Open
Abstract
Osteological correlates preserve more readily than their soft tissue counterparts in the fossil record; therefore, they can more often provide insight into the soft tissue anatomy of the organism. These insights can in turn elucidate the biology of these extinct organisms. In this study, we reconstruct the pelvic girdle and hind limb musculature of the giant titanosaurian sauropod Dreadnoughtus schrani based on observations of osteological correlates and Extant Phylogenetic Bracket comparisons. Recovered fossils of Dreadnoughtus exhibit remarkably well-preserved, well-developed, and extensive muscle scars. Furthermore, this taxon is significantly larger bodied than any titanosaurian for which a myological reconstruction has previously been performed, rendering this contribution highly informative for the group. All 20 of the muscles investigated in this study are sufficiently well supported to enable reconstruction of at least one division, including reconstruction of the M. ischiocaudalis for the first time in a sauropod dinosaur. In total, 34 osteological correlates were identified on the pelvic girdle and hind limb remains of Dreadnoughtus, allowing the reconstruction of 14 muscles on the basis of Level I or Level II inferences (i.e., not Level I' or Level II' inferences). Comparisons among titanosaurians suggest widespread myological variation, yet potential phylogenetic and other paleobiologic patterns are often obscured by fragmentary preservation, infrequent myological studies, and lack of consensus on the phylogenetic placement of many taxa. However, a ventrolateral accessory process is present on the preacetabular lobe of the ilium in all of the largest titanosauriforms that preserve this skeletal element, suggesting that the presence of this process (representing the origin of the M. puboischiofemoralis internus part II) may be associated with extreme body size. By identifying such myological patterns among titanosauriforms, we can begin to address specific evolutionary and biomechanical questions related to their skeletal anatomy, how they were capable of leaving wide-gauge trackways, and resulting locomotor attributes unique to this clade.
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Affiliation(s)
| | | | - Matthew C. Lamanna
- Section of Vertebrate PaleontologyCarnegie Museum of Natural HistoryPittsburghPAUSA
| | - Kenneth J. Lacovara
- Department of GeologyRowan UniversityGlassboroNJUSA,School of Earth and EnvironmentRowan UniversityGlassboroNJUSA
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11
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Lefebvre R, Allain R, Houssaye A, Cornette R. Disentangling biological variability and taphonomy: shape analysis of the limb long bones of the sauropodomorph dinosaur Plateosaurus. PeerJ 2020; 8:e9359. [PMID: 32775045 PMCID: PMC7382942 DOI: 10.7717/peerj.9359] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 05/25/2020] [Indexed: 12/31/2022] Open
Abstract
Sauropodomorph dinosaurs constitute a well-studied clade of dinosaurs, notably because of the acquisition of gigantism within this group. The genus Plateosaurus is one of the best-known sauropodomorphs, with numerous remains from various localities. Its tumultuous taxonomic history suggests the relevance of addressing its intrageneric shape variability, mixed with taphonomic modifications of the original bone shape. Here we investigate quantitatively the morphological variation of Plateosaurus occurring at the genus level by studying the shape variation of a sample of limb long bones. By means of 3D geometric morphometrics, the analysis of the uncorrelated variation permits separation of the variation estimated as obviously taphonomically influenced from the more biologically plausible variation. Beyond the dominant taphonomic signal, our approach permits interpretation of the most biologically plausible features, even on anatomical parts influenced by taphonomic deformations. Those features are thus found on a quantitative basis from the variation of samples containing fossil specimens, by taking the impact of taphonomy into account, which is paramount in order to avoid making biologically ambiguous interpretations.
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Affiliation(s)
- Rémi Lefebvre
- Mécanismes Adaptatifs et Évolution, UMR 7179, MNHN, CNRS, Muséum National d'Histoire Naturelle, Paris, France
| | - Ronan Allain
- Centre de Recherche en Paléontologie - Paris, UMR 7207, MNHN, CNRS, SU, Muséum National d'Histoire Naturelle, Paris, France
| | - Alexandra Houssaye
- Mécanismes Adaptatifs et Évolution, UMR 7179, MNHN, CNRS, Muséum National d'Histoire Naturelle, Paris, France
| | - Raphaël Cornette
- Institut de Systématique, Évolution, Biodiversité, UMR7205, MNHN, CNRS, SU, EPHE, UA, Muséum National d'Histoire Naturelle, Paris, France
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12
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Voegele KK, Ullmann PV, Lamanna MC, Lacovara KJ. Appendicular myological reconstruction of the forelimb of the giant titanosaurian sauropod dinosaur Dreadnoughtus schrani. J Anat 2020; 237:133-154. [PMID: 32141103 DOI: 10.1111/joa.13176] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 01/06/2020] [Accepted: 01/29/2020] [Indexed: 01/08/2023] Open
Abstract
Soft tissues are variably preserved in the fossil record with external tissues, such as skin and feathers, more frequently preserved than internal tissues (e.g. muscles). More commonly, soft tissues leave traces of their locations on bones and, for muscles, these clues can be used to reconstruct the musculature of extinct vertebrates, thereby enhancing our understanding of how these organisms moved and the evolution of their locomotor patterns. Herein we reconstruct the forelimb and shoulder girdle musculature of the giant titanosaurian sauropod Dreadnoughtus schrani based on observations of osteological correlates and dissections of taxa comprising the Extant Phylogenetic Bracket of non-avian dinosaurs (crocodilians and birds). Fossils of Dreadnoughtus exhibit remarkably well-preserved, well-developed, and extensive muscle scars. Furthermore, this taxon is significantly larger-bodied than any titanosaurian for which a myological reconstruction has previously been attempted, rendering this myological study highly informative for the clade. In total, 28 muscles were investigated in this study, for which 46 osteological correlates were identified; these osteological correlates allowed the reconstruction of 16 muscles on the basis of Level I or Level II inferences (i.e. not Level I' or Level II' inferences). Comparisons with other titanosaurians suggest widespread myological variation in the clade, although potential phylogenetic patterns are often obscured by fragmentary preservation, infrequent myological studies, and lack of consensus on the systematic position of many taxa. By identifying myological variations within the clade, we can begin to address specific evolutionary and biomechanical questions related to the locomotor evolution in these sauropods.
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Affiliation(s)
| | - Paul V Ullmann
- Department of Geolgoy, Rowan University, Glassboro, NJ, USA
| | - Matthew C Lamanna
- Section of Vertebrate Paleontology, Carnegie Museum of Natural History, Pittsburgh, PA, USA
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Piechowski R, Tałanda M. The locomotor musculature and posture of the early dinosauriform Silesaurus opolensis provides a new look into the evolution of Dinosauromorpha. J Anat 2020; 236:1044-1100. [PMID: 32003023 DOI: 10.1111/joa.13155] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 11/27/2019] [Accepted: 12/29/2019] [Indexed: 11/30/2022] Open
Abstract
It is widely accepted that ornithodirans (bird lineage) and some pseudosuchians (crocodilian lineage) achieved fully erect limb posture in different ways. Ornithodirans have buttress-erected hindlimbs, while some advanced pseudosuchians have pillar-erected hindlimbs. Analysis of the musculoskeletal apparatus of the early dinosauriform Silesaurus opolensis challenges this view. This ornithodiran had pillar-erected hindlimbs like some pseudosuchians. This condition could be autapomorphic or represents a transitional state between adductor-controlled limb posture of early dinosauromorphs and the buttress-erected hindlimbs of dinosaurs. This sequence of changes is supported by Triassic tracks left by animals of the dinosaurian lineage. It was associated with the strong development of knee flexors and extensors. Furthermore, the forelimbs of Silesaurus were fully erect, analogously to those of early sauropods. Members of both lineages reduced the muscles related to the protraction, retraction and bending of the limb. They used forelimbs more as a body support and less for propulsion. A similar scapula and humerus construction can be found in the Lagerpetidae and Lewisuchus, suggesting that long, slender, fully erected forelimbs are primitive for all Dinosauromorpha, not just Silesauridae. Early dinosaurs redeveloped several muscle attachments on the forelimb, probably in relation to bipedality.
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Affiliation(s)
- Rafał Piechowski
- Institute of Paleobiology, Polish Academy of Sciences, Warsaw, Poland.,Department of Palaeobiology and Evolution, Faculty of Biology, Biological and Chemical Research Centre, University of Warsaw, Warsaw, Poland
| | - Mateusz Tałanda
- Department of Palaeobiology and Evolution, Faculty of Biology, Biological and Chemical Research Centre, University of Warsaw, Warsaw, Poland
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Ezcurra MD, Nesbitt SJ, Fiorelli LE, Desojo JB. New Specimen Sheds Light on the Anatomy and Taxonomy of the Early Late Triassic Dinosauriforms from the Chañares Formation, NW Argentina. Anat Rec (Hoboken) 2019; 303:1393-1438. [DOI: 10.1002/ar.24243] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 04/26/2019] [Accepted: 06/06/2019] [Indexed: 12/12/2022]
Affiliation(s)
- Martín D. Ezcurra
- Sección Paleontología de VertebradosCONICET ‐ Museo Argentino de Ciencias Naturales “Bernardino Rivadavia” Buenos Aires Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) Buenos Aires Argentina
| | | | - Lucas E. Fiorelli
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) Buenos Aires Argentina
- Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja (CRILAR)Provincia de La Rioja, UNLAR, SEGEMAR, UNCa, CONICET La Rioja Argentina
| | - Julia B. Desojo
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) Buenos Aires Argentina
- División Paleontología Vertebrados, Museo de La PlataFacultad de Ciencias Naturales y Museo Buenos Aires Argentina
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Riga BJG, Lamanna MC, Otero A, David LDO, Kellner AWA, Ibiricu LM. An overview of the appendicular skeletal anatomy of South American titanosaurian sauropods, with definition of a newly recognized clade. AN ACAD BRAS CIENC 2019; 91:e20180374. [PMID: 31340217 DOI: 10.1590/0001-3765201920180374] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 01/28/2019] [Indexed: 11/22/2022] Open
Abstract
In the last two decades, the number of phylogenetically informative anatomical characters recognized in the appendicular skeleton of titanosaurian sauropod dinosaurs has increased dramatically with the discovery of new and comparatively complete specimens. Here we provide an overview of the appendicular skeletal morphology of South American titanosaurs and discuss its significance for phylogenetic reconstruction. The appendicular skeletal diversity of South American titanosaurs is substantially greater than was initially appreciated. Moreover, some regions of the appendicular skeleton, such as the pes, exhibit remarkable variability in form. Multiple synapomorphies of Titanosauria and the less inclusive clades Lithostrotia and Saltasauridae consist of characters of the girdles and limbs. Although the phylogenetic definitions of titanosaurian clades such as Saltasaurinae and Lognkosauria are stable, the taxonomic content of these clades has varied in recent analyses depending on the phylogenetic topology recovered. Within Titanosauria, the results of four recent, largely independent analyses support the existence of a derived titanosaurian lineage distinct from the 'Saltasaurinae line,' which is herein termed Colossosauria. At present, this clade is mainly comprised by taxa within Lognkosauria and Rinconsauria, and is useful in discussions of titanosaurian lower-level relationships.
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Affiliation(s)
- Bernardo J González Riga
- CONICET/Laboratorio y Museo de Dinosaurios, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo, Padre Contreras 1300, Parque Gral. San Martin, Mendoza Capital 5500, Mendoza, Argentina
| | - Matthew C Lamanna
- Section of Vertebrate Paleontology, Carnegie Museum of Natural History, 4400 Forbes Avenue, Pittsburgh, Pennsylvania 15213, U.S.A
| | - Alejandro Otero
- CONICET, División Paleontología de Vertebrados, Museo de La Plata, Paseo del Bosque, s/n, La Plata, B1900FWA, Argentina
| | - Leonardo D Ortiz David
- CONICET/Laboratorio y Museo de Dinosaurios, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo, Padre Contreras 1300, Parque Gral. San Martin, Mendoza Capital 5500, Mendoza, Argentina
| | - Alexander W A Kellner
- Laboratório de Systemática e Tafonomia de Vertebrados Fósseis, Departamento de Geologia e Paleontologia, Museu Nacional, Universidade Federal do Rio de Janeiro, Quinta da Boa Vista, São Cristóvão, 20940-040 Rio de Janeiro, RJ, Brazil
| | - Lucio M Ibiricu
- Instituto Patagónico de Geología y Paleontología (IPGP-CONICET), Boulevard Almirante Brown, 2915, Puerto Madryn, 9120, Chubut, Argentina
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Rauhut OWM, Tischlinger H, Foth C. A non-archaeopterygid avialan theropod from the Late Jurassic of southern Germany. eLife 2019; 8:e43789. [PMID: 31084702 PMCID: PMC6516837 DOI: 10.7554/elife.43789] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 04/10/2019] [Indexed: 01/05/2023] Open
Abstract
The Late Jurassic 'Solnhofen Limestones' are famous for their exceptionally preserved fossils, including the urvogel Archaeopteryx, which has played a pivotal role in the discussion of bird origins. Here we describe a new, non-archaeopterygid avialan from the Lower Tithonian Mörnsheim Formation of the Solnhofen Archipelago, Alcmonavis poeschli gen. et sp. nov. Represented by a right wing, Alcmonavis shows several derived characters, including a pronounced attachment for the pectoralis muscle, a pronounced tuberculum bicipitale radii, and a robust second manual digit, indicating that it is a more derived avialan than Archaeopteryx. Several modifications, especially in muscle attachments of muscles that in modern birds are related to the downstroke of the wing, indicate an increased adaptation of the forelimb for active flapping flight in the early evolution of birds. This discovery indicates higher avialan diversity in the Late Jurassic than previously recognized.
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Affiliation(s)
- Oliver WM Rauhut
- Staatliche naturwissenschaftliche Sammlungen Bayerns (SNSB)Bayerische Staatssammlung für Paläontologie und GeologieMünchenGermany
- Department for Earth and Environmental Sciences, Palaeontology and GeobiologyLudwig-Maximilians-UniversitätMünchenGermany
- GeoBioCenterLudwig-Maximilians-UniversitätMünchenGermany
| | | | - Christian Foth
- Department of GeosciencesUniversité de FribourgFribourgSwitzerland
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