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Lacerda MBS, Bittencourt JS, Hutchinson JR. Macroevolutionary patterns in the pelvis, stylopodium and zeugopodium of megalosauroid theropod dinosaurs and their importance for locomotor function. ROYAL SOCIETY OPEN SCIENCE 2023; 10:230481. [PMID: 37593714 PMCID: PMC10427828 DOI: 10.1098/rsos.230481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Accepted: 07/27/2023] [Indexed: 08/19/2023]
Abstract
During the Mesozoic, non-avian theropods represented one of the most successful clades globally distributed, with a wide diversity of forms. An example is the clade Megalosauroidea, which included medium- to large-bodied forms. Here, we analyse the macroevolution of the locomotor system in early Theropoda, emphasizing the Megalosauroidea. We scored the Spinosaurus neotype in a published taxon-character matrix and described the associated modifications in character states, mapping them onto a phylogeny and using these to study disparity. In the evolution of Megalosauroidea, there was the mosaic emergence of a low swollen ridge; enlargement of the posterior brevis fossa and emergence of a posterodorsal process on the ilium in some megalosauroids; emergence of a femoral head oriented anteromedially and medially angled, and appearance of posterolaterally oriented medial femoral condyles in spinosaurids. The greatest morphological disparity is in the ilium of megalosaurids; the ischium seems to have a high degree of homoplasy; there is a clear distinction in the femoral morphospace regarding megalosauroids and other theropods; piatnitzkysaurids show considerable disparity of zeugopodial characters. These reconstructions of osteological evolution form a stronger basis on which other studies could build, such as mapping of pelvic/appendicular musculature and/or correlating skeletal traits with changes in locomotor function.
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Affiliation(s)
- Mauro B. S. Lacerda
- Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, The Royal Veterinary College, Hatfield AL9 7TA, UK
- Pós-Graduação em Zoologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, 31270-901, Brazil
| | - Jonathas S. Bittencourt
- Departamento de Geologia, Instituto de Geociências, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil
| | - John R. Hutchinson
- Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, The Royal Veterinary College, Hatfield AL9 7TA, UK
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2
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Naish D, Cau A. The osteology and affinities of Eotyrannus lengi, a tyrannosauroid theropod from the Wealden Supergroup of southern England. PeerJ 2022; 10:e12727. [PMID: 35821895 PMCID: PMC9271276 DOI: 10.7717/peerj.12727] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 12/10/2021] [Indexed: 01/07/2023] Open
Abstract
Eotyrannus lengi Hutt et al., 2001 from the Lower Cretaceous Wessex Formation (part of the Wealden Supergroup) of the Isle of Wight, southern England, is described in detail, compared with other theropods, and evaluated in a new phylogenetic analysis. Eotyrannus is represented by a single individual that would have been c. 4.5 m long; it preserves the anterior part of the skull, a partial forelimb and pectoral girdle, various cervical, dorsal and caudal vertebrae, rib fragments, part of the ilium, and hindlimb elements excluding the femur. Lack of fusion with regard to both neurocentral and sacral sutures indicates subadult status. Eotyrannus possesses thickened, fused, pneumatic nasals with deep lateral recesses, elongate, tridactyl forelimbs and a tyrannosaurid-like scapulocoracoid. The short preantorbital ramus of the maxilla and nasals that are approximately seven times longer than they are wide show that Eotyrannus was not longirostrine. A posterodorsally inclined ridge on the ilium's lateral surface fails to reach the dorsal margin: a configuration seen elsewhere in Juratyrant. Eotyrannus is not arctometatarsalian. Autapomorphies include the presence of curving furrows on the dentary, a block-like humeral entepicondyle, and a distoproximally aligned channel close to the distolateral border of the tibia. Within Tyrannosauroidea, E. lengi is phylogenetically intermediate between Proceratosauridae and Yutyrannus and the clade that includes Xiongguanlong, Megaraptora, Dryptosaurus and Tyrannosauridae. We do not find support for a close affinity between Eotyrannus and Juratyrant. Our analysis supports the inclusion of Megaraptora within Tyrannosauroidea and thus increases Cretaceous tyrannosauroid diversity and disparity. A proposal that Eotyrannus might belong within Megaraptora, however, is based on character states not present in the taxon. Several theropods from the Wessex Formation are based on material that overlaps with the E. lengi holotype but none can be shown to be synonymous with it.
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Affiliation(s)
- Darren Naish
- School of Biological Sciences, Faculty of Environment and Life Sciences, University of Southampton, Southampton, UK
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3
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Ibrahim N, Sereno PC, Varricchio DJ, Martill DM, Dutheil DB, Unwin DM, Baidder L, Larsson HCE, Zouhri S, Kaoukaya A. Geology and paleontology of the Upper Cretaceous Kem Kem Group of eastern Morocco. Zookeys 2020; 928:1-216. [PMID: 32362741 PMCID: PMC7188693 DOI: 10.3897/zookeys.928.47517] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 03/02/2020] [Indexed: 11/30/2022] Open
Abstract
The geological and paleoenvironmental setting and the vertebrate taxonomy of the fossiliferous, Cenomanian-age deltaic sediments in eastern Morocco, generally referred to as the “Kem Kem beds”, are reviewed. These strata are recognized here as the Kem Kem Group, which is composed of the lower Gara Sbaa and upper Douira formations. Both formations have yielded a similar fossil vertebrate assemblage of predominantly isolated elements pertaining to cartilaginous and bony fishes, turtles, crocodyliforms, pterosaurs, and dinosaurs, as well as invertebrate, plant, and trace fossils. These fossils, now in collections around the world, are reviewed and tabulated. The Kem Kem vertebrate fauna is biased toward large-bodied carnivores including at least four large-bodied non-avian theropods (an abelisaurid, Spinosaurus, Carcharodontosaurus, and Deltadromeus), several large-bodied pterosaurs, and several large crocodyliforms. No comparable modern terrestrial ecosystem exists with similar bias toward large-bodied carnivores. The Kem Kem vertebrate assemblage, currently the best documented association just prior to the onset of the Cenomanian-Turonian marine transgression, captures the taxonomic diversity of a widespread northern African fauna better than any other contemporary assemblage from elsewhere in Africa.
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Affiliation(s)
- Nizar Ibrahim
- Department of Biology, University of Detroit Mercy, Detroit, Michigan 48221, USA
| | - Paul C Sereno
- Department of Organismal Biology and Anatomy and Committee on Evolutionary Biology, University of Chicago, Chicago, Illinois 60637, USA
| | - David J Varricchio
- Department of Earth Sciences, Montana State University, Bozeman, Montana 59717, USA
| | - David M Martill
- School of the Environment, Geography and Geological Sciences, University of Portsmouth, Portsmouth PO1 3QL, UK
| | - Didier B Dutheil
- Centre de Recherche sur la Paléobiodiversité et les Paléoenvironnements, UMR7207 (CNRS-MNHN-UPMC), Muséum national d'Histoire naturelle, 75005 Paris, France
| | - David M Unwin
- School of Museum Studies, University of Leicester, Leicester LE1 7RF, UK
| | - Lahssen Baidder
- Laboratoire Géosciences, Département de Géologie, Faculté des Sciences Aïn Chock, Université Hassan II, Casablanca, Morocco
| | - Hans C E Larsson
- Redpath Museum, McGill University, Montreal, Quebec H3A 0C4, Canada
| | - Samir Zouhri
- Laboratoire de Biodiversité et Santé, Faculté des Sciences Aïn Chock, Université Hassan II, Casablanca, Morocco
| | - Abdelhadi Kaoukaya
- Laboratoire Géosciences, Département de Géologie, Faculté des Sciences Aïn Chock, Université Hassan II, Casablanca, Morocco
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4
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Chure DJ, Loewen MA. Cranial anatomy of Allosaurus jimmadseni, a new species from the lower part of the Morrison Formation (Upper Jurassic) of Western North America. PeerJ 2020; 8:e7803. [PMID: 32002317 PMCID: PMC6984342 DOI: 10.7717/peerj.7803] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 08/31/2019] [Indexed: 11/20/2022] Open
Abstract
Allosaurus is one of the best known theropod dinosaurs from the Jurassic and a crucial taxon in phylogenetic analyses. On the basis of an in-depth, firsthand study of the bulk of Allosaurus specimens housed in North American institutions, we describe here a new theropod dinosaur from the Upper Jurassic Morrison Formation of Western North America, Allosaurus jimmadseni sp. nov., based upon a remarkably complete articulated skeleton and skull and a second specimen with an articulated skull and associated skeleton. The present study also assigns several other specimens to this new species, Allosaurus jimmadseni, which is characterized by a number of autapomorphies present on the dermal skull roof and additional characters present in the postcrania. In particular, whereas the ventral margin of the jugal of Allosaurus fragilis has pronounced sigmoidal convexity, the ventral margin is virtually straight in Allosaurus jimmadseni. The paired nasals of Allosaurus jimmadseni possess bilateral, blade-like crests along the lateral margin, forming a pronounced nasolacrimal crest that is absent in Allosaurus fragilis.
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Affiliation(s)
- Daniel J Chure
- Dinosaur National Monument (retired), Jensen, UT, USA.,Independent Researcher, Jensen, UT, USA
| | - Mark A Loewen
- Natural History Museum of Utah, University of Utah, Salt Lake City, UT, USA.,Department of Geology and Geophysics, University of Utah, Salt Lake City, UT, USA
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5
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Rauhut OWM, Pol D. Probable basal allosauroid from the early Middle Jurassic Cañadón Asfalto Formation of Argentina highlights phylogenetic uncertainty in tetanuran theropod dinosaurs. Sci Rep 2019; 9:18826. [PMID: 31827108 PMCID: PMC6906444 DOI: 10.1038/s41598-019-53672-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 11/01/2019] [Indexed: 11/09/2022] Open
Abstract
Tetanurae, the most successful clade of theropod dinosaurs, including modern birds, split into three major clades early in their evolutionary history: Megalosauroidea, Coelurosauria, and Allosauroidea. The oldest tetanurans occur in the earliest Middle Jurassic, but the early fossil record of the clade is still poor. Here we report one of the oldest known and most complete pre-Late Jurassic tetanuran, the probable allosauroid Asfaltovenator vialidadi gen. et sp. nov., which has an unusual character combination, uniting features currently considered to be apomorphic of different tetanuran lineages. A phylogenetic analysis resulted in a monophyletic Carnosauria (Allosauroidea + Megalosauroidea), and the inclusion of the new taxon significantly changes topology within carnosaurs. The analysis shows concentrated homoplasy in proximal nodes at the base of Tetanurae, and a temporal peak at the Pliensbachian-Toarcian extinction event, recently identified as a potential driver of tetanuran radiation. These results highlight the complex morphological evolution in the early radiation of tetanuran theropods, in which convergences and parallelisms were extremely common. This pattern seems to be a common feature in rapid radiation events of major clades of vertebrates and might explain the common difficulties to unravel phylogenetic relationships of important lineages at the base of major clades.
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Affiliation(s)
- Oliver W M Rauhut
- SNSB-Bayerische Staatssammlung für Paläontologie und Geologie, Richard-Wagner-Str. 10, 80333, Munich, Germany. .,Section Palaeontology & Geobiology, Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität, Richard-Wagner-Str. 10, 80333, Munich, Germany. .,GeoBioCenter, Ludwig-Maximilians-Universität, Richard-Wagner-Str. 10, 80333, Munich, Germany.
| | - Diego Pol
- CONICET, Museo Paleontológico Egidio Feruglio, Avenida Fontana 140, 9100, Trelew, Argentina
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6
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Chokchaloemwong D, Hattori S, Cuesta E, Jintasakul P, Shibata M, Azuma Y. A new carcharodontosaurian theropod (Dinosauria: Saurischia) from the Lower Cretaceous of Thailand. PLoS One 2019; 14:e0222489. [PMID: 31596853 PMCID: PMC6784982 DOI: 10.1371/journal.pone.0222489] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 08/30/2019] [Indexed: 11/28/2022] Open
Abstract
The isolated fossil remains of an allosauroid theropod from the Lower Cretaceous Khok Kruat Formation of Khorat, Thailand, are described in this study. Detailed observations support the establishment of a new allosauroid, Siamraptor suwati gen. et sp. nov. This new taxon is based on a composite cranial and postcranial skeleton comprising premaxilla, maxilla, jugal, surangular, prearticular, articular, vertebrae, manual ungual, ischium, tibia, and pedal phalanx. It is distinguished from other allosauroids by characters such as a jugal with straight ventral margin and dorsoventrally deep anterior process below the orbit, a surangular with a deep oval concavity at the posterior end of the lateral shelf and four posterior surangular foramina, a long and narrow groove along the suture between the surangular and the prearticular, an articular with a foramen at the notch of the suture with the prearticular, an anterior cervical vertebra with a pneumatic foramen (so-called 'pleurocoel') excavating parapophysis, and cervical and posterior dorsal vertebrae penetrated by a pair of small foramina bilaterally at the base of the neural spine. The presence of a huge number of camerae and pneumatopores in cranial and axial elements reveals a remarkable skeletal pneumatic system in this new taxon. Moreover, the phylogenetic analyses revealed that Siamraptor is a basal taxon of Carcharodontosauria, involving a new sight of the paleobiogeographical context of this group. Siamraptor is the best preserved carcharodontosaurian theropod in Southeast Asia, and it sheds new light on the early evolutionary history of Carcharodontosauria.
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Affiliation(s)
- Duangsuda Chokchaloemwong
- Northeastern Research Institute of Petrified Wood and Mineral Resources, Nakhon Ratchasima Rajabhat University, Suranaree Subdistict, Mueang, Nakhon Ratchasima District, Nakhon Ratchasima, Thailand
| | - Soki Hattori
- Institute of Dinosaur Research, Fukui Prefectural University, Kenjojima, Matsuoka, Eiheiji–Cho, Fukui, Japan
- Fukui Prefectural Dinosaur Museum, Muroko, Terao, Katsuyama, Fukui, Japan
| | - Elena Cuesta
- Institute of Dinosaur Research, Fukui Prefectural University, Kenjojima, Matsuoka, Eiheiji–Cho, Fukui, Japan
| | - Pratueng Jintasakul
- Northeastern Research Institute of Petrified Wood and Mineral Resources, Nakhon Ratchasima Rajabhat University, Suranaree Subdistict, Mueang, Nakhon Ratchasima District, Nakhon Ratchasima, Thailand
| | - Masateru Shibata
- Institute of Dinosaur Research, Fukui Prefectural University, Kenjojima, Matsuoka, Eiheiji–Cho, Fukui, Japan
- Fukui Prefectural Dinosaur Museum, Muroko, Terao, Katsuyama, Fukui, Japan
| | - Yoichi Azuma
- Institute of Dinosaur Research, Fukui Prefectural University, Kenjojima, Matsuoka, Eiheiji–Cho, Fukui, Japan
- Fukui Prefectural Dinosaur Museum, Muroko, Terao, Katsuyama, Fukui, Japan
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7
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Canoville A, Schweitzer MH, Zanno LE. Systemic distribution of medullary bone in the avian skeleton: ground truthing criteria for the identification of reproductive tissues in extinct Avemetatarsalia. BMC Evol Biol 2019; 19:71. [PMID: 30845911 PMCID: PMC6407237 DOI: 10.1186/s12862-019-1402-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 02/25/2019] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Medullary bone (MB) is an estrogen-dependent, sex-specific tissue produced by female birds during lay and inferred to be present in extinct avemetatarsalians (bird-line archosaurs). Although preliminary studies suggest that MB can be deposited within most skeletal elements, these are restricted to commercial layers or hormonally treated male pigeons, which are poor analogues for wild birds. By contrast, studies in wild bird species noted the presence of MB almost exclusively within limb bones, spurring the misconception that MB deposition is largely restricted to these regions. These disparate claims have cast doubt on the nature of MB-like tissues observed in some extinct avemetatarsalians because of their "unusual" anatomical locations. Furthermore, previous work reported that MB deposition is related to blood supply and pneumatization patterns, yet these hypotheses have not been tested widely in birds. To document the skeletal distribution of MB across Neornithes, reassess previous hypotheses pertaining to its deposition/distribution patterns, and refine the set of criteria by which to evaluate the nature of purported MB tissue in extinct avemetatarsalians, we CT-scanned skeletons of 40 female birds (38 species) that died during the egg-laying cycle, recorded presence or absence of MB in 19 skeletal regions, and assessed pneumatization of stylopods. Selected elements were destructively analyzed to ascertain the chemical and histological nature of observed endosteal bone tissues in contentious skeletal regions. RESULTS Although its skeletal distribution varies interspecifically, we find MB to be a systemic tissue that can be deposited within virtually all skeletal regions, including cranial elements. We also provide evidence that the deposition of MB is dictated by skeletal distribution patterns of both pneumaticity and bone marrow; two factors linked to ecology (body size, foraging). Hence, skeletal distribution of MB can be extensive in small-bodied and diving birds, but more restricted in large-bodied species or efficient flyers. CONCLUSIONS Previously outlined anatomical locations of purported MB in extinct taxa are invalid criticisms against their potential reproductive nature. Moreover, the proposed homology of lung tissues between birds and some extinct avemetatarsalians permit us to derive a series of location-based predictions that can be used to critically evaluate MB-like tissues in fossil specimens.
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Affiliation(s)
- Aurore Canoville
- Paleontology, North Carolina Museum of Natural Sciences, Raleigh, NC, USA.
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA.
| | - Mary H Schweitzer
- Paleontology, North Carolina Museum of Natural Sciences, Raleigh, NC, USA
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA
| | - Lindsay E Zanno
- Paleontology, North Carolina Museum of Natural Sciences, Raleigh, NC, USA
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA
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8
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Mannion PD, Upchurch P, Schwarz D, Wings O. Taxonomic affinities of the putative titanosaurs from the Late Jurassic Tendaguru Formation of Tanzania: phylogenetic and biogeographic implications for eusauropod dinosaur evolution. Zool J Linn Soc 2019. [DOI: 10.1093/zoolinnean/zly068] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Philip D Mannion
- Department of Earth Science and Engineering, Imperial College London, London, UK
| | - Paul Upchurch
- Department of Earth Sciences, University College London, London, UK
| | | | - Oliver Wings
- Niedersächsisches Landesmuseum Hannover, Hannover, Germany
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9
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Rauhut OWM, Piñuela L, Castanera D, García-Ramos JC, Sánchez Cela I. The largest European theropod dinosaurs: remains of a gigantic megalosaurid and giant theropod tracks from the Kimmeridgian of Asturias, Spain. PeerJ 2018; 6:e4963. [PMID: 30002951 PMCID: PMC6035862 DOI: 10.7717/peerj.4963] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 05/23/2018] [Indexed: 12/20/2022] Open
Abstract
The Kimmeridgian Vega, Tereñes and Lastres formations of Asturias have yielded a rich vertebrate fauna, represented by both abundant tracks and osteological remains. However, skeletal remains of theropod dinosaurs are rare, and the diversity of theropod tracks has only partially been documented in the literature. Here we describe the only non-dental osteological theropod remain recovered so far, an isolated anterior caudal vertebra, as well as the largest theropod tracks found. The caudal vertebra can be shown to represent a megalosaurine megalosaurid and represents the largest theropod skeletal remain described from Europe so far. The tracks are also amongst the largest theropod footprints reported from any setting and can be assigned to two different morphotypes, one being characterized by its robustness and a weak mesaxony, and the other characterized by a strong mesaxony, representing a more gracile trackmaker. We discuss the recently proposed distinction between robust and gracile large to giant theropod tracks and their possible trackmakers during the Late Jurassic-Berriasian. In the absence of complete pedal skeletons of most basal tetanurans, the identity of the maker of Jurassic giant theropod tracks is difficult to establish. However, the notable robustness of megalosaurine megalosaurids fits well with the described robust morphotypes, whereas more slender large theropod tracks might have been made by a variety of basal tetanurans, including allosaurids, metriocanthosaurids or afrovenatorine megalosaurids, or even exceptionally large ceratosaurs. Concerning osteological remains of large theropods from the Late Jurassic of Europe, megalosaurids seem to be more abundant than previously recognized and occur in basically all Jurassic deposits where theropod remains have been found, whereas allosauroids seem to be represented by allosaurids in Western Europe and metriacanthosaurids in more eastern areas. Short-term fluctuations in sea level might have allowed exchange of large theropods between the islands that constituted Europe during the Late Jurassic.
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Affiliation(s)
- Oliver W M Rauhut
- SNSB, Bayerische Staatssammlung für Paläontologie und Geologie, Munich, Germany.,GeoBioCenter, Ludwig-Maximilians-University, Munich, Germany.,Department for Earth and Environmental Sciences, Ludwig-Maximilians-University, Munich, Germany
| | | | - Diego Castanera
- SNSB, Bayerische Staatssammlung für Paläontologie und Geologie, Munich, Germany.,GeoBioCenter, Ludwig-Maximilians-University, Munich, Germany
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10
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Xing L, Caldwell MW, Chen R, Nydam RL, Palci A, Simões TR, McKellar RC, Lee MSY, Liu Y, Shi H, Wang K, Bai M. A mid-Cretaceous embryonic-to-neonate snake in amber from Myanmar. SCIENCE ADVANCES 2018; 4:eaat5042. [PMID: 30035227 PMCID: PMC6051735 DOI: 10.1126/sciadv.aat5042] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 06/27/2018] [Indexed: 06/08/2023]
Abstract
We present the first known fossilized snake embryo/neonate preserved in early Late Cretaceous (Early Cenomanian) amber from Myanmar, which at the time, was an island arc including terranes from Austral Gondwana. This unique and very tiny snake fossil is an articulated postcranial skeleton, which includes posterior precloacal, cloacal, and caudal vertebrae, and details of squamation and body shape; a second specimen preserves a fragment of shed skin interpreted as a snake. Important details of skeletal ontogeny, including the stage at which snake zygosphene-zygantral joints began to form along with the neural arch lamina, are preserved. The vertebrae show similarities to those of fossil Gondwanan snakes, suggesting a dispersal route of Gondwanan faunas to Laurasia. Finally, the new species is the first Mesozoic snake to be found in a forested environment, indicating greater ecological diversity among early snakes than previously thought.
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Affiliation(s)
- Lida Xing
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China
- School of the Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China
| | - Michael W. Caldwell
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
| | - Rui Chen
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Randall L. Nydam
- Department of Anatomy, Midwestern University, Glendale, AZ 85308, USA
| | - Alessandro Palci
- South Australian Museum, North Terrace, Adelaide, South Australia 5000, Australia
- College of Science and Engineering, Flinders University, Adelaide, South Australia, Australia
| | - Tiago R. Simões
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
| | - Ryan C. McKellar
- Royal Saskatchewan Museum, Regina, Saskatchewan S4P 4W7, Canada
- Biology Department, University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | - Michael S. Y. Lee
- South Australian Museum, North Terrace, Adelaide, South Australia 5000, Australia
- College of Science and Engineering, Flinders University, Adelaide, South Australia, Australia
| | - Ye Liu
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
- Paleo-diary Museum of Natural History, Beijing 100097, China
| | | | - Kuan Wang
- Paleo-diary Museum of Natural History, Beijing 100097, China
| | - Ming Bai
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
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11
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Maganuco S, Dal Sasso C. The smallest biggest theropod dinosaur: a tiny pedal ungual of a juvenile Spinosaurus from the Cretaceous of Morocco. PeerJ 2018; 6:e4785. [PMID: 29868253 PMCID: PMC5984586 DOI: 10.7717/peerj.4785] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 04/27/2018] [Indexed: 11/20/2022] Open
Abstract
We describe a nearly complete pedal ungual phalanx, discovered in the Kem Kem Beds (Cenomanian) of Tafilalt region, south-eastern Morocco. The bone is symmetric, pointed, low, elongate, and almost flat ventrally in lateral aspect. This peculiar morphology allows to refer the specimen to the smallest known individual of the genus Spinosaurus. The bone belongs to an early juvenile individual and it is proportionally identical to the ungual of the third digit of a large partial skeleton recently found, suggesting an isometric growth for this part of the pes and the retention of peculiar locomotor adaptations—such as traversing soft substrates or paddling—during the entire lifespan.
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12
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Rauhut OWM, Foth C, Tischlinger H. The oldest Archaeopteryx (Theropoda: Avialiae): a new specimen from the Kimmeridgian/Tithonian boundary of Schamhaupten, Bavaria. PeerJ 2018; 6:e4191. [PMID: 29383285 PMCID: PMC5788062 DOI: 10.7717/peerj.4191] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 12/04/2017] [Indexed: 11/25/2022] Open
Abstract
The iconic primeval bird Archaeopteryx was so far mainly known from the Altmühltal Formation (early Tithonian) of Bavaria, southern Germany, with one specimen having been found in the overlying Mörnsheim Formation. A new specimen (the 12th skeletal specimen) from the earliest Tithonian Painten Formation of Schamhaupten (Bavaria) represents the so far oldest representative of the genus. The new specimen shows several interesting anatomical details, including the presence of a postorbital in contact with the jugal, the presence of a separate prefrontal and coronoid, and opisthocoelous mid-cervical vertebrae. Based on observations on the new specimen, we discuss several problematic issues concerning Archaeopteryx, including the monophyly and diagnosis of the genus, the absence/presence of the sternum, the position of the gastralia, and variation in morphometrics and dental morphology in that genus. Based on a new diagnosis for the genus Archaeopteryx, the Berlin, Eichstätt, Solnhofen, Munich, Daiting, Thermopolis, 11th, and 12th specimens can be referred to this genus with high certainty. The Maxberg specimen is very probably also an Archaeopteryx, based on overall similarity, although none of the diagnostic characters can be evaluated with certainty. The ninth specimen (‘chicken wing’) might be Archaeopteryx, but cannot be referred to the genus with any certainty. In comparison with other paravians, the presence of distally thickened anterior pectoral ribs indicates that a rather large cartilagenous sternum was present in this taxon. In contrast to non-opisthopubic theropods, opisthopubic taxa, such as Archaeopteryx and many other paravians, have the posterior end of the gastral basket preserved at about half-length of the pubis, which might reflect the post-mortem collapse of enlarged abdominal air sacs in these taxa. Specimens that can be referred to Archaeopteryx show a high amount of variation, both in the morphometrics of the limb bones as well as in the dentition. In respect to the latter aspect, variation is found in tooth number, spacing, orientation, and morphology, with no two specimens showing the exact same pattern. The significance of this variation is unclear, and possible explanations reach from high intraspecific (and possibly ontogenetic and/or sexual dimorphic) variation to the possibility that the known specimens represent a ‘species flock’ of Archaeopteryx, possibly due to island speciation after the initial dispersal of the genus into the Solnhofen Archipelago.
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Affiliation(s)
- Oliver W M Rauhut
- SNSB-Bayerische Staatssammlung für Paläontologie und Geologie, Munich, Germany.,Department of Earth and Environmental Sciences, Ludwig-Maximilians University, Munich, Germany.,GeoBioCenter, Ludwig-Maximilians University, Munich, Germany
| | - Christian Foth
- Department of Geosciences, Université de Fribourg, Fribourg, Switzerland.,Staatliches Museum für Naturkunde, Stuttgart, Germany
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Ezcurra MD. The phylogenetic relationships of basal archosauromorphs, with an emphasis on the systematics of proterosuchian archosauriforms. PeerJ 2016; 4:e1778. [PMID: 27162705 PMCID: PMC4860341 DOI: 10.7717/peerj.1778] [Citation(s) in RCA: 115] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 02/18/2016] [Indexed: 11/20/2022] Open
Abstract
The early evolution of archosauromorphs during the Permo-Triassic constitutes an excellent empirical case study to shed light on evolutionary radiations in deep time and the timing and processes of recovery of terrestrial faunas after a mass extinction. However, macroevolutionary studies of early archosauromorphs are currently limited by poor knowledge of their phylogenetic relationships. In particular, one of the main early archosauromorph groups that need an exhaustive phylogenetic study is "Proterosuchia," which as historically conceived includes members of both Proterosuchidae and Erythrosuchidae. A new data matrix composed of 96 separate taxa (several of them not included in a quantitative phylogenetic analysis before) and 600 osteological characters was assembled and analysed to generate a comprehensive higher-level phylogenetic hypothesis of basal archosauromorphs and shed light on the species-level interrelationships of taxa historically identified as proterosuchian archosauriforms. The results of the analysis using maximum parsimony include a polyphyletic "Prolacertiformes" and "Protorosauria," in which the Permian Aenigmastropheus and Protorosaurus are the most basal archosauromorphs. The enigmatic choristoderans are either found as the sister-taxa of all other lepidosauromorphs or archosauromorphs, but consistently placed within Sauria. Prolacertids, rhynchosaurs, allokotosaurians and tanystropheids are the major successive sister clades of Archosauriformes. The Early Triassic Tasmaniosaurus is recovered as the sister-taxon of Archosauriformes. Proterosuchidae is unambiguosly restricted to five species that occur immediately after and before the Permo-Triassic boundary, thus implying that they are a short-lived "disaster" clade. Erythrosuchidae is composed of eight nominal species that occur during the Early and Middle Triassic. "Proterosuchia" is polyphyletic, in which erythrosuchids are more closely related to Euparkeria and more crownward archosauriforms than to proterosuchids, and several species are found widespread along the archosauromorph tree, some being nested within Archosauria (e.g., "Chasmatosaurus ultimus," Youngosuchus). Doswelliids and proterochampsids are recovered as more closely related to each other than to other archosauromorphs, forming a large clade (Proterochampsia) of semi-aquatic to aquatic forms that includes the bizarre genus Vancleavea. Euparkeria is one of the sister-taxa of the clade composed of proterochampsians and archosaurs. The putative Indian archosaur Yarasuchus is recovered in a polytomy with Euparkeria and more crownward archosauriforms, and as more closely related to the Russian Dongusuchus than to other species. Phytosaurs are recovered as the sister-taxa of all other pseudosuchians, thus being nested within Archosauria.
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Affiliation(s)
- Martín D. Ezcurra
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, United Kingdom
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Evers SW, Rauhut OWM, Milner AC, McFeeters B, Allain R. A reappraisal of the morphology and systematic position of the theropod dinosaur Sigilmassasaurus from the "middle" Cretaceous of Morocco. PeerJ 2015; 3:e1323. [PMID: 26500829 PMCID: PMC4614847 DOI: 10.7717/peerj.1323] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 09/24/2015] [Indexed: 11/20/2022] Open
Abstract
Sigilmassasaurus brevicollis is an enigmatic theropod dinosaur from the early Late Cretaceous (Cenomanian) of Morocco, originally based on a few isolated cervical vertebrae. Ever since its original description, both its taxonomic validity and systematic affinities were contentious. Originally considered to represent its own family, Sigilmassasauridae, the genus has variously been suggested to represent a carcharodontosaurid, an ornithischian, and, more recently, a spinosaurid. Here we describe new remains referrable to this taxon and re-evaluate its taxonomic status and systematic affinities. Based on the new remains, a re-evaluation of the original materials, and comparisons with other spinosaurids, the holotype of Sigilmassasaurus brevicollis is identified as an anterior dorsal, rather than a cervical vertebra, and differences between elements referred to this taxon can be explained by different positions of the elements in question within the vertebral column. Many characters used previously to diagnose the genus and species are found to be more widespread among basal tetanurans, and specifically spinosaurids. However, the taxon shows several autapomorphies that support its validity, including the presence of a strongly rugose, ventrally offset triangular platform that is confluent with a ventral keel anteriorly in the mid-cervical vertebral centra and a strongly reduced lateral neural arch lamination, with no or an incomplete distinction between anterior and posterior centrodiapophyseal laminae in the posterior cervical and anterior dorsal vertebrae. We argue furthermore that Spinosaurus maroccanus, also described on the basis of isolated cervical vertebrae from the same stratigraphic unit and in the same paper as Sigilmassasaurus brevicollis, is a subjective synonym of the latter. Both a detailed comparison of this taxon with other theropods and a formal phylogenetic analysis support spinosaurid affintities for Sigilmassasaurus. However, we reject the recently proposed synonymy of both Spinosaurus maroccanus and Sigilmassasurus brevicollis with Spinosaurus aegyptiacus from the Cenomanian of Egypt, as there are clear differences between the vertebrae of these taxa, and they do not share any derived character that is not found in other spinosaurids. Together with a comparison with other spinosaurid vertebral material from the Kem Kem, this suggests that more than one taxon of spinosaurid was present in the Kem Kem assemblage of Morocco, so the referral of non-overlapping material from this unit to a single taxon should be regarded with caution.
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Affiliation(s)
- Serjoscha W Evers
- Department of Earth Sciences, University of Oxford , Oxford , United Kingdom ; Department für Geo- und Umweltwissenschaften, Ludwig-Maximilians-Universität München , Munich , Germany
| | - Oliver W M Rauhut
- Bayerische Staatssammlung für Paläontologie und Geologie, Staatliche Naturwissenschaftliche Sammlungen Bayerns (SNSB) , Munich , Germany ; Department für Geo- und Umweltwissenschaften and GeoBioCenter, Ludwig-Maximilians-University , Munich , Germany
| | - Angela C Milner
- Department of Earth Sciences, Natural History Museum , London , United Kingdom
| | | | - Ronan Allain
- Département Histoire de la Terre, Centre de Recherches sur la Paléobiodiversité et les Paléoenvironnements (CR2P), Muséum National d'Histoire Naturelle, Université Pierre et Marie Curie , Paris , France
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Langer MC, Rincón AD, Ramezani J, Solórzano A, Rauhut OWM. New dinosaur (Theropoda, stem-Averostra) from the earliest Jurassic of the La Quinta formation, Venezuelan Andes. ROYAL SOCIETY OPEN SCIENCE 2014; 1:140184. [PMID: 26064540 PMCID: PMC4448901 DOI: 10.1098/rsos.140184] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Accepted: 09/10/2014] [Indexed: 06/04/2023]
Abstract
Dinosaur skeletal remains are almost unknown from northern South America. One of the few exceptions comes from a small outcrop in the northernmost extension of the Andes, along the western border of Venezuela, where strata of the La Quinta Formation have yielded the ornithischian Laquintasaura venezuelae and other dinosaur remains. Here, we report isolated bones (ischium and tibia) of a small new theropod, Tachiraptor admirabilis gen. et sp. nov., which differs from all previously known members of the group by an unique suite of features of its tibial articulations. Comparative/phylogenetic studies place the new form as the sister taxon to Averostra, a theropod group that is known primarily from the Middle Jurassic onwards. A new U-Pb zircon date (isotope dilution thermal-ionization mass spectrometry; ID-TIMS method) from the bone bed matrix suggests an earliest Jurassic maximum age for the La Quinta Formation. A dispersal-vicariance analysis suggests that such a stratigraphic gap is more likely to be filled by new records from north and central Pangaea than from southern areas. Indeed, our data show that the sampled summer-wet equatorial belt, which yielded the new taxon, played a pivotal role in theropod evolution across the Triassic-Jurassic boundary.
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Affiliation(s)
- Max C. Langer
- Laboratório de Paleontologia de Ribeirão Preto, FFCLRP, Universidade de São Paulo, Avenida Bandeirantes 3900, 14040-901, Ribeirão Preto-SP, Brazil
| | - Ascanio D. Rincón
- Laboratorio de Paleontología, Centro de Ecología, Instituto Venezolano de Investigaciones Científcas (IVIC), Carretera Panamericana Km 11, 1020-A Caracas, Venezuela
| | - Jahandar Ramezani
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, USA
| | - Andrés Solórzano
- Laboratorio de Paleontología, Centro de Ecología, Instituto Venezolano de Investigaciones Científcas (IVIC), Carretera Panamericana Km 11, 1020-A Caracas, Venezuela
| | - Oliver W. M. Rauhut
- SNSB, Bayerische Staatssammlung für Paläontologie und Geologie and Department of Earth and Environmental Sciences, Ludwig-Maximilians-University, Richard-Wagner-Strasse 10, Munich, Germany
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Fanti F, Cau A, Hassine M, Contessi M. A new sauropod dinosaur from the Early Cretaceous of Tunisia with extreme avian-like pneumatization. Nat Commun 2013; 4:2080. [DOI: 10.1038/ncomms3080] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Accepted: 05/30/2013] [Indexed: 11/10/2022] Open
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Abstract
The distribution of species body size is critically important for determining resource use within a group or clade. It is widely known that non-avian dinosaurs were the largest creatures to roam the Earth. There is, however, little understanding of how maximum species body size was distributed among the dinosaurs. Do they share a similar distribution to modern day vertebrate groups in spite of their large size, or did they exhibit fundamentally different distributions due to unique evolutionary pressures and adaptations? Here, we address this question by comparing the distribution of maximum species body size for dinosaurs to an extensive set of extant and extinct vertebrate groups. We also examine the body size distribution of dinosaurs by various sub-groups, time periods and formations. We find that dinosaurs exhibit a strong skew towards larger species, in direct contrast to modern day vertebrates. This pattern is not solely an artefact of bias in the fossil record, as demonstrated by contrasting distributions in two major extinct groups and supports the hypothesis that dinosaurs exhibited a fundamentally different life history strategy to other terrestrial vertebrates. A disparity in the size distribution of the herbivorous Ornithischia and Sauropodomorpha and the largely carnivorous Theropoda suggests that this pattern may have been a product of a divergence in evolutionary strategies: herbivorous dinosaurs rapidly evolved large size to escape predation by carnivores and maximise digestive efficiency; carnivores had sufficient resources among juvenile dinosaurs and non-dinosaurian prey to achieve optimal success at smaller body size.
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Affiliation(s)
- Eoin J. O’Gorman
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
- School of Biology and Environmental Science, Science Centre West, University College Dublin, Belfield, Dublin, Ireland
| | - David W. E. Hone
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
- School of Biology and Environmental Science, Science Centre West, University College Dublin, Belfield, Dublin, Ireland
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Nesbitt SJ. The Early Evolution of Archosaurs: Relationships and the Origin of Major Clades. BULLETIN OF THE AMERICAN MUSEUM OF NATURAL HISTORY 2011. [DOI: 10.1206/352.1] [Citation(s) in RCA: 529] [Impact Index Per Article: 40.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Mudroch A, Richter U, Joger U, Kosma R, Idé O, Maga A. Didactyl tracks of paravian theropods (Maniraptora) from the ?Middle Jurassic of Africa. PLoS One 2011; 6:e14642. [PMID: 21339816 PMCID: PMC3038851 DOI: 10.1371/journal.pone.0014642] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2010] [Accepted: 12/12/2010] [Indexed: 11/19/2022] Open
Abstract
Background A new dinosaur tracksite from ?Middle Jurassic sediments of the Irhazer Group on the plains of Agadez (Rep. Niger, northwest Africa) revealed extraordinarily well preserved didactyl tracks of a digitigrade bipedal trackmaker. The distinct morphology of the pes imprints indicates a theropod trackmaker from a paravian maniraptoran closely related to birds. Methodology/Principal Findings The early age and the morphological traits of the tracks allow for description of the new ichnotaxon Paravipus didactyloides. A total of 120 tracks are assigned to 5 individual trackways. The ‘medium-sized’ tracks with an average footprint length of 27.5 cm and footprint width of 23.1 cm are deeply imprinted into the track bearing sandstone. Conclusions/Significance A comparison with other didactyl tracks gives new insights into the foot morphology of advanced maniraptoran theropods and contributes to knowledge of their evolutionary history. The new ichnotaxon takes an important position in the ichnological fossil record of Gondwana and the mid-Jurassic biota worldwide, because it is among the earliest known records of paravian maniraptorans and of didactyl theropod tracks from Africa.
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BENSON ROGERBJ. A description ofMegalosaurus bucklandii(Dinosauria: Theropoda) from the Bathonian of the UK and the relationships of Middle Jurassic theropods. Zool J Linn Soc 2010. [DOI: 10.1111/j.1096-3642.2009.00569.x] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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BRUSATTE STEPHENL, BENSON ROGERBJ, CURRIE PHILIPJ, XIJIN ZHAO. The skull of Monolophosaurus jiangi (Dinosauria: Theropoda) and its implications for early theropod phylogeny and evolution. Zool J Linn Soc 2010. [DOI: 10.1111/j.1096-3642.2009.00563.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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RAUHUT OLIVERWM, MILNER ANGELAC, MOORE-FAY SCOTT. Cranial osteology and phylogenetic position of the theropod dinosaurProceratosaurus bradleyi(Woodward, 1910) from the Middle Jurassic of England. Zool J Linn Soc 2010. [DOI: 10.1111/j.1096-3642.2009.00591.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Remes K, Ortega F, Fierro I, Joger U, Kosma R, Ferrer JMM, Ide OA, Maga A. A new basal sauropod dinosaur from the middle Jurassic of Niger and the early evolution of sauropoda. PLoS One 2009; 4:e6924. [PMID: 19756139 PMCID: PMC2737122 DOI: 10.1371/journal.pone.0006924] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2009] [Accepted: 08/01/2009] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND The early evolution of sauropod dinosaurs is poorly understood because of a highly incomplete fossil record. New discoveries of Early and Middle Jurassic sauropods have a great potential to lead to a better understanding of early sauropod evolution and to reevaluate the patterns of sauropod diversification. PRINCIPAL FINDINGS A new sauropod from the Middle Jurassic of Niger, Spinophorosaurus nigerensis n. gen. et sp., is the most complete basal sauropod currently known. The taxon shares many anatomical characters with Middle Jurassic East Asian sauropods, while it is strongly dissimilar to Lower and Middle Jurassic South American and Indian forms. A possible explanation for this pattern is a separation of Laurasian and South Gondwanan Middle Jurassic sauropod faunas by geographic barriers. Integration of phylogenetic analyses and paleogeographic data reveals congruence between early sauropod evolution and hypotheses about Jurassic paleoclimate and phytogeography. CONCLUSIONS Spinophorosaurus demonstrates that many putatively derived characters of Middle Jurassic East Asian sauropods are plesiomorphic for eusauropods, while South Gondwanan eusauropods may represent a specialized line. The anatomy of Spinophorosaurus indicates that key innovations in Jurassic sauropod evolution might have taken place in North Africa, an area close to the equator with summer-wet climate at that time. Jurassic climatic zones and phytogeography possibly controlled early sauropod diversification.
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Affiliation(s)
- Kristian Remes
- Paleontology, Steinmann Institute for Geology, Mineralogy and Paleontology, University of Bonn, Bonn, Germany.
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Prasad GVR, Sahni A. Late Cretaceous continental vertebrate fossil record from India: Palaeobiogeographical insights. ACTA ACUST UNITED AC 2009. [DOI: 10.2113/gssgfbull.180.4.369] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Abstract
Geophysical data suggested a minimum of 35 Ma physical isolation for the Indian plate from the time of its separation from Madagascar around 88 Ma ago to its final collision with Asia in the Early-Middle Eocene (55-50 Ma ago). Such an extended period of segregation of any landmass is expected to result in genetic isolation of pre-existing populations leading to the development of endemic biota. Therefore, continental Late Cretaceous biota of India hold the key to our understanding of effects of long isolation and northward drift of the Indian plate over different latitudinal belts. Focused palaeontological research in the last one and half decades on the Deccan volcano-sedimentary sequences (infra– and intertrappean beds) has resulted in the recovery of diverse assemblages of vertebrate, invertebrate, and plant fossils. The Deccan volcano-sedimentary sequences were dated Late Cretaceous-Early Palaeocene in age based on vertebrate, ostracod, planktonic foraminiferal, palynofloral and geochronological data. Critical evaluation of the biota from these strata brings out a complex biogeographical picture. The Late Cretaceous biota of India include some taxa of Gondwanan affinities (leptodactylid, hylid and ranoid frogs, madtsoiid and nigerophiid snakes, pelomedusoid turtles, mesosuchian crocodiles, abelisaurid dinosaurs, and gondwanathere mammals), Gondwanan relicts (haramiyidan mammals), certain taxa of Laurasian affinities (pelobatid and Gobiatinae frogs, anguimorph lizards, eutherian mammals, charophytes), and ostracods of predominantly endemic nature. Since India was once part of the former Gondwanaland, the presence of Gondwanan taxa in the Late Cretaceous of India is not anomalous from a biogeographic point of view. These taxa might have been derived from Gondwanan stocks that boarded the Indian plate prior to its break-up from Africa or might represent immigrants from South America that reached the Indo-Madagascar block via Antarctica and the Kerguelen Plateau/Gunnerus ridge not later than 80 Ma. However, the presence of Laurasian non-marine taxa in the northward drifting Indian plate defies palaeogeographical data showing a wide body of marine water (Tethys) separating India from Asia. In the light of latest palaeontological, stratigraphic, geochemical and geophysical data from the northern margin of India, one cannot rule out dispersals from the northern landmasses across the Kohistan and Dras island-arcs and Trans-Himalayan magmatic arc. Other biogeographical models, such as “Out-of-India Dispersals” for many vertebrate, invertebrate, and plant groups, also deserve a close examination. At present, limited quantitative fossil data is available to test these biogeographical models.
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Affiliation(s)
- Guntupalli V. R. Prasad
- Department of Geology, University of Jammu, Jammu 180 006, India.
- Department of Geology, University of Jammu, Jammu 180 006, India.
| | - Ashok Sahni
- CAS in Geology, Panjab University, Chandigarh 160 014, India
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Canudo JI, Barco JL, Pereda-Suberbiola X, Ruiz-Omeñaca JI, Salgado L, Torcida Fernández-Baldor F, Gasulla JM. What Iberian dinosaurs reveal about the bridge said to exist between Gondwana and Laurasia in the Early Cretaceous. ACTA ACUST UNITED AC 2009. [DOI: 10.2113/gssgfbull.180.1.5] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Abstract
Some Cretaceous dinosaur taxa with a broad enough record on the continents of the northern hemisphere (Laurasia) or in the southern continents (Gondwana) have been interpreted as Laurasian or Gondwanan in origin. The occasional presence of these taxa outside Laurasia or Gondwana respectively has frequently been explained in terms of dispersal from their place of origin by means of land bridges that are indeterminate in location and character. One example of such a dispersal event is provided by the Early Cretaceous dinosaurs of Europe and Africa. Certain European taxa have been interpreted as having their origin in Gondwana. If we regard these presences common to both areas as being the result of a point of communication between Laurasia and western Gondwana or at least of sporadic flows in both directions during the Early Cretaceous, we may opt for dispersal as an explanation.
It has been assumed that there was an intercontinental bridge between Africa and Europe passing through the archipelago of which Iberia formed a part. This interpretation emerged from the idea that such a bridge existed in the Late Jurassic, explaining the presence of similar ornithopod dinosaurs in Africa and Europe. However, from the end of the Early Jurassic a period of “rift” began on the southern Iberian margin, entailing the formation of a sedimentary furrow with pelagic sedimentation in what is known as the Subbetic zone. Moreover, the differences in the observed dinosaur fauna between western Gondwana and the Iberian Peninsula in the Neocomian can be explained as the result of endemism and regional extinctions. The archipelago that formed the Iberian plate was Laurasia’s closest continental mass to Gondwana during the Neocomian, yet there was still a separation of several hundred kilometres of open ocean without islands. Such a barrier would seem difficult for dinosaurs to overcome. As such, we lack proof of communication between the two supercontinents via Iberia during the Neocomian.
The situation appears to change in the Barremian-Aptian transition. Some of the taxa present in the Hauterivian-Barremian of Europe are recorded in Gondwana from the Aptian onwards. This can possibly be explained in terms of the more complete record that exists, but it cannot be ruled out that a communication was established between Gondwana and Laurasia at the end of the Barremian. For the time being, we lack geological support for this bridge in Iberia, yet it might be located in Apulia, where there is a great development of shallow-shelf carbonates with dinosaur remains from the period in question.
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Affiliation(s)
- José Ignacio Canudo
- Grupo Aragosaurus (www.aragosaurus.com). Paleontología, Facultad de Ciencias, Universidad de Zaragoza, Pedro Cerbuna 12, 50009 Zaragoza, Spain.
| | - José Luis Barco
- Grupo Aragosaurus (www.aragosaurus.com). Paleontología, Facultad de Ciencias, Universidad de Zaragoza, Pedro Cerbuna 12, 50009 Zaragoza, Spain.
- Paleoymas, Nuestra Señora del Salz, 50017 Zaragoza, Spain.
| | - Xabier Pereda-Suberbiola
- Universidad del País Vasco/EHU, Dpto. Estratigrafía y Paleontología, Facultad de Ciencia y Tecnología, Apartado 644, 48080 Bilbao, Spain.
| | - José Ignacio Ruiz-Omeñaca
- Grupo Aragosaurus (www.aragosaurus.com). Paleontología, Facultad de Ciencias, Universidad de Zaragoza, Pedro Cerbuna 12, 50009 Zaragoza, Spain.
- Museo del Jurásico de Asturias (MUJA), 33328 Colunga, Asturias, Spain.
| | - Leonardo Salgado
- Museo de Ciencias Naturales de la Universidad Nacional de Comahué, Buenos Aires 1400, 8300 Neuquén, Argentina.
| | | | - José Miguel Gasulla
- Unidad de Paleontología, Departamento de Biología, Universidad Autónoma de Madrid, Campus de Cantoblanco, 28049 Madrid, Spain
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SMITH NATHAND, MAKOVICKY PETERJ, HAMMER WILLIAMR, CURRIE PHILIPJ. Osteology of Cryolophosaurus ellioti (Dinosauria: Theropoda) from the Early Jurassic of Antarctica and implications for early theropod evolution. Zool J Linn Soc 2007. [DOI: 10.1111/j.1096-3642.2007.00325.x] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Coria RA, Salgado L. Mid-Cretaceous turnover of saurischian dinosaur communities: evidence from the Neuquén Basin. ACTA ACUST UNITED AC 2005. [DOI: 10.1144/gsl.sp.2005.252.01.16] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AbstractSuccessional changes are recorded among saurischian dinosaur faunas throughout the Cretaceous of the Neuquén Basin. Both sauropod and theropod lineages present in NW Patagonia show comparable transformations and indicate that some clades did not survive the Late Turonian boundary. Similar patterns of changes are observed in other Patagonian sedimentary basins. Diplodocoid sauropods and carcharodontosaurid theropods are not yet recorded in levels younger than Turonian, while titanosaurians and abelisauroids are present before and after this period. Important floral changes during the mid-Cretaceous, mainly related to the proliferation of angiosperms, could be one element that influenced some dinosaurian associations.
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Affiliation(s)
- Rodolfo A. Coria
- CONICET, Secretaría de Estado de Cultura de Neuquén, Museo Carmen Funes
Av. Córdoba 55, (8318) Plaza Huincul, Neuquín, Argentina
| | - Leonardo Salgado
- CONICET, Museo Universidad Nacional del Comahue
Buenos Aires 1400, (8300) Neuquín, Argentina
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Sereno PC, Wilson JA, Conrad JL. New dinosaurs link southern landmasses in the Mid-Cretaceous. Proc Biol Sci 2004; 271:1325-30. [PMID: 15306329 PMCID: PMC1691741 DOI: 10.1098/rspb.2004.2692] [Citation(s) in RCA: 215] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abelisauroid predators have been recorded almost exclusively from South America, India and Madagascar, a distribution thought to document persistent land connections exclusive of Africa. Here, we report fossils from three stratigraphic levels in the Cretaceous of Niger that provide definitive evidence that abelisauroid dinosaurs and their immediate antecedents were also present on Africa. The fossils include an immediate abelisauroid antecedent of Early Cretaceous age (ca. 130-110 Myr ago), early members of the two abelisauroid subgroups (Noasauridae, Abelisauridae) of Mid-Cretaceous age (ca. 110 Myr ago) and a hornless abelisaurid skull of early Late Cretaceous age (ca. 95 Myr ago). Together, these fossils fill in the early history of the abelisauroid radiation and provide key evidence for continued faunal exchange among Gondwanan landmasses until the end of the Early Cretaceous (ca. 100 Myr ago).
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Affiliation(s)
- Paul C Sereno
- Department of Organismal Biology and Anatomy, University of Chicago, 1027 East 57th Street, Chicago, IL 60637, USA.
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Abstract
One of the ultimate aims of systematics is the reconstruction of the tree of life. This is a huge undertaking that is inhibited by the existence of a computational limit to the inclusiveness of phylogenetic analyses. Supertree methods have been developed to overcome, or at least to go around this problem by combining smaller, partially overlapping cladograms. Here, we present a very inclusive generic-level supertree of Dinosauria (covering a total of 277 genera), which is remarkably well resolved and provides some clarity in many contentious areas of dinosaur systematics.
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Affiliation(s)
- Davide Pisani
- Department of Earth Sciences, University of Bristol, Bristol BS8 1RJ, UK.
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31
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Barrett PM, Willis KJ. Did dinosaurs invent flowers? Dinosaur-angiosperm coevolution revisited. Biol Rev Camb Philos Soc 2001; 76:411-47. [PMID: 11569792 DOI: 10.1017/s1464793101005735] [Citation(s) in RCA: 161] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Angiosperms first appeared in northern Gondwana during the Early Cretaceous, approximately 135 million years ago. Several authors have hypothesised that the origin of angiosperms, and the tempo and pattern of their subsequent radiation, was mediated by changes in the browsing behaviour of large herbivorous dinosaurs (sauropods and ornithischians). Moreover, the taxonomic and ecological radiation of angiosperms has been associated with the evolution of complex jaw mechanisms among ornithischian dinosaurs. Here, we review critically the evidence for dinosaur-angiosperm interactions during the Cretaceous Period, providing explicit spatiotemporal comparisons between evolutionary and palaeoecological events in both the dinosaur and angiosperm fossil records and an assessment of the direct and indirect evidence for dinosaur diets. We conclude that there are no strong spatiotemporal correlations in support of the hypothesis that dinosaurs were causative agents in the origin of angiosperms; however, dinosaur-angiosperm interactions in the Late Cretaceous may have resulted in some coevolutionary interactions, although direct evidence of such interactions is scanty at present. It is likely that other animal groups (insects, arboreal mammals) had a greater impact on angiosperm diversity during the Cretaceous than herbivorous dinosaurs. Elevated levels of atmospheric CO2 might have played a critical role in the initial stages of the angiosperm radiation.
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Affiliation(s)
- P M Barrett
- Department of Zoology, University of Oxford, UK.
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33
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Farlow JO, Gatesy SM, Holtz TR, Hutchinson JR, Robinson JM. Theropod Locomotion. ACTA ACUST UNITED AC 2000. [DOI: 10.1093/icb/40.4.640] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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34
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Sereno PC, Beck AL, Dutheil DB, Larsson HC, Lyon GH, Moussa B, Sadleir RW, Sidor CA, Varricchio DJ, Wilson GP, Wilson JA. Cretaceous sauropods from the sahara and the uneven rate of skeletal evolution among dinosaurs. Science 1999; 286:1342-7. [PMID: 10558986 DOI: 10.1126/science.286.5443.1342] [Citation(s) in RCA: 186] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Lower Cretaceous fossils from central Niger document the succession of sauropod dinosaurs on Africa as it drifted into geographic isolation. A new broad-toothed genus of Neocomian age ( approximately 135 million years ago) shows few of the specializations of other Cretaceous sauropods. A new small-bodied sauropod of Aptian-Albian age ( approximately 110 million years ago), in contrast, reveals the highly modified cranial form of rebbachisaurid diplodocoids. Rates of skeletal change in sauropods and other major groups of dinosaurs are estimated quantitatively and shown to be highly variable.
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Affiliation(s)
- PC Sereno
- Department of Organismal Biology and Anatomy, University of Chicago, 1027 East 57 Street, Chicago, IL 60637, USA. Laboratoire de Paleontologie-EPHE-Museum National d'Histoire Naturelle, 8 rue du Buffon, 75005 Paris, France. Project Explorati
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35
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Sampson SD, Witmer LM, Forster CA, Krause DW, O'Connor PM, Dodson P, Ravoavy F. Predatory dinosaur remains from madagascar: implications for the cretaceous biogeography of gondwana. Science 1998; 280:1048-51. [PMID: 9582112 DOI: 10.1126/science.280.5366.1048] [Citation(s) in RCA: 269] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Recent discoveries of fossil vertebrates from the Late Cretaceous of Madagascar include several specimens of a large theropod dinosaur. One specimen includes a nearly complete and exquisitely preserved skull with thickened pneumatic nasals, a median frontal horn, and a dorsal projection on the parietals. The new materials are assigned to the enigmatic theropod group Abelisauridae on the basis of a number of unique features. Fossil remains attributable to abelisaurids are restricted to three Gondwanan landmasses: South America, Madagascar, and the Indian subcontinent. This distribution is consistent with a revised paleogeographic reconstruction that posits prolonged links between these landmasses (via Antarctica), perhaps until late in the Late Cretaceous.
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Affiliation(s)
- SD Sampson
- S. D. Sampson, Department of Anatomy, New York College of Osteopathic Medicine of New York Institute of Technology, Old Westbury, NY 11568, USA. L. M. Witmer, Department of Biomedical Sciences, College of Osteopathic Medicine, Ohi
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Rich TH, Vickers-Rich P, Constantine A, Flannery TF, Kool L, van Klaveren N. A tribosphenic mammal from the Mesozoic of Australia. Science 1997; 278:1438-42. [PMID: 9367951 DOI: 10.1126/science.278.5342.1438] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A small, well-preserved dentary of a tribosphenic mammal with the most posterior premolar and all three molars in place has been found in Aptian (Early Cretaceous) rocks of southeastern Australia. In most respects, dental and mandibular anatomy of the specimen is similar to that of primitive placental mammals. With the possible exception of a single tooth reported as Eocene in age, terrestrial placentals are otherwise unknown in Australia until the Pliocene. This possible Australian placental is similar in age to Prokennalestes from the late Aptian/early Albian Khoboor Beds of Mongolia, the oldest currently accepted member of the infraclass Placentalia.
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Affiliation(s)
- T H Rich
- Museum of Victoria, Post Office Box 666E, Melbourne, Victoria 3001, Australia
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Abstract
Most recent studies of dinosaur phylogeny have concentrated on theropods and ornithischians. As a result, the evolutionary relationships of sauropod dinosaurs are poorly understood. In this paper previous studies of sauropod phylogeny are reviewed and contrasted with the results of a recent cladistic analysis. This analysis forms the basis for a reconstruction of sauropod phylogeny. Sauropods diverged from other dinosaurs at some time in the Upper Triassic, but a large part of their early history is totally unknown.
Vulcanodon
is currently the most primitive sauropod. Many, but perhaps not all, of the Jurassic Chinese sauropods form a monophyletic radiation (the Euhelopodidae) which may reflect the geographic isolation of China during the Lower Jurassic. Members of the Euhelopodidae, such as
Mamenchisaurus
, are not considered to be closely related to the Diplodocidae. ‘Forked’ chevrons, which have played such an important role in previous studies of sauropod phylogeny, are here considered to have evolved twice within the Sauropoda. This convergence may reflect a correlation between chevron shape and the use of the tail as a weapon within these two sauropod families. The ‘Neosauropoda’ (sister group to the Euhelopodidae) contains the Brachiosauridae, Camarasauridae and the new superfamilies Titanosauroidea and Diplodocoidea. The Cetiosauridae (here defined in a rather restricted sense) is also provisionally included within the Neosauropoda, but may be removed in future studies. The enigmatic Upper Cretaceous sauropod,
Opisthocoelicaudia
, is thought to be the sister taxon to the Titanosauridae and not a camarasaurid as previously suggested. The Diplodocoidea contains two well established families, the Dicraeosauridae and Diplodocidae, and the new family Nemegtosauridae. Finally, an overview of sauropod phylogeny is compared with recently published palaeogeographic reconstructions. There are many difficulties associated with the analysis of sauropod biogeographic distribution. Nevertheless, some aspects of sauropod phylogeny may be linked to the break-up of Laurasia and Gondwanaland during the Jurassic and Cretaceous.
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Affiliation(s)
- Philip J. Currie
- The author is at the Tyrrell Museum of Palaeontology, Box 7500, Drumheller, Alberta T0J 0Y0, Canada
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Sereno PC, Dutheil DB, Iarochene M, Larsson HCE, Lyon GH, Magwene PM, Sidor CA, Varricchio DJ, Wilson JA. Predatory Dinosaurs from the Sahara and Late Cretaceous Faunal Differentiation. Science 1996; 272:986-91. [PMID: 8662584 DOI: 10.1126/science.272.5264.986] [Citation(s) in RCA: 296] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Late Cretaceous (Cenomanian) fossils discovered in the Kem Kem region of Morocco include large predatory dinosaurs that inhabited Africa as it drifted into geographic isolation. One, represented by a skull approximately 1.6 meters in length, is an advanced allosauroid referable to the African genus Carcharodontosaurus. Another, represented by a partial skeleton with slender proportions, is a new basal coelurosaur closely resembling the Egyptian genus Bahariasaurus. Comparisons with Cretaceous theropods from other continents reveal a previously unrecognized global radiation of carcharodontosaurid predators. Substantial geographic differentiation of dinosaurian faunas in response to continental drift appears to have arisen abruptly at the beginning of the Late Cretaceous.
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Affiliation(s)
- PC Sereno
- P. C. Sereno, H. C. E. Larsson, P. M. Magwene, C. A. Sidor, J. A. Wilson, Department of Organismal Biology and Anatomy, University of Chicago, 1027 East 57th Street, Chicago, IL 60637, USA. D. B. Dutheil, 48 rue de la Rochefoucauld, 75009 Paris, France. M. Iarochene, Ministere de l'Energie et des Mines, Rabat, Morocco. G. H. Lyon, 3551 Carter Hill Road, Montgomery, AL 36111, USA. D. J. Varricchio, Old Trail Museum, Post Office Box 919, Choteau, MT 59422, USA
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42
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Affiliation(s)
- Eric Buffetaut
- Centre National de la Recherche Scientifique, and Laboratoire de Paléontologie des Vertébrés, Université Paris 6, Case 106, 4 place Jussieu, 75252 Paris Cedex 05, France
| | - Gilles Cuny
- Centre National de la Recherche Scientifique, and Laboratoire de Paléontologie des Vertébrés, Université Paris 6, Case 106, 4 place Jussieu, 75252 Paris Cedex 05, France
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43
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Olshevsky G. African Dinosaur Discoveries. Science 1995. [DOI: 10.1126/science.267.5205.1750.a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- George Olshevsky
- Editor, Archosaurian Articulations, Post Office Box 543, Central Park Station, Buffalo, NY 14215-0543, USA
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Appenzeller T. Patagonian Dinosaurs Reveal A Cosmopolitan Cretaceous. Science 1995; 267:817-8. [PMID: 17813900 DOI: 10.1126/science.267.5199.817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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