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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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Cashmore DD, Butler RJ, Maidment SCR. Taxonomic identification bias does not drive patterns of abundance and diversity in theropod dinosaurs. Biol Lett 2021; 17:20210168. [PMID: 34256583 PMCID: PMC8278044 DOI: 10.1098/rsbl.2021.0168] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
The ability of palaeontologists to correctly diagnose and classify new fossil species from incomplete morphological data is fundamental to our understanding of evolution. Different parts of the vertebrate skeleton have different likelihoods of fossil preservation and varying amounts of taxonomic information, which could bias our interpretations of fossil material. Substantial previous research has focused on the diversity and macroevolution of non-avian theropod dinosaurs. Theropods provide a rich dataset for analysis of the interactions between taxonomic diagnosability and fossil preservation. We use specimen data and formal taxonomic diagnoses to create a new metric, the Likelihood of Diagnosis, which quantifies the diagnostic likelihood of fossil species in relation to bone preservation potential. We use this to assess whether a taxonomic identification bias impacts the non-avian theropod fossil record. We find that the patterns of differential species abundance and clade diversity are not a consequence of their relative diagnosability. Although there are other factors that bias the theropod fossil record that are not investigated here, our results suggest that patterns of relative abundance and diversity for theropods might be more representative of Mesozoic ecology than often considered.
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Affiliation(s)
- Daniel D Cashmore
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Richard J Butler
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Susannah C R Maidment
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.,Department of Earth Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, UK
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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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Marsh AD, Rowe TB. Anatomy and systematics of the sauropodomorph Sarahsaurus aurifontanalis from the Early Jurassic Kayenta Formation. PLoS One 2018; 13:e0204007. [PMID: 30304035 PMCID: PMC6179219 DOI: 10.1371/journal.pone.0204007] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 09/01/2018] [Indexed: 12/13/2022] Open
Abstract
Sarahsaurus aurifontanalis, from the Kayenta Formation of Arizona, is one of only three sauropodomorph dinosaurs known from the Early Jurassic of North America. It joins Anchisaurus polyzelus, from the older Portland Formation of the Hartford Basin, and Seitaad reussi, from the younger Navajo Sandstone of Utah, in representing the oldest North American sauropodomorphs. If it is true that sauropodomorphs were absent from North America during the Late Triassic, the relationship among these three dinosaurs offers a test of the mechanisms that drove recovery in North American biodiversity following the end-Triassic extinction event. Here we provide the first thorough description of Sarahsaurus aurifontanalis based on completed preparation and computed tomographic imaging of the holotype and referred specimens. With new anatomical data, our phylogenetic analysis supports the conclusion that Sarahsaurus aurifontanalis is nested within the primarily Gondwanan clade Massospondylidae, while agreeing with previous analyses that the three North American sauropodomorphs do not themselves form an exclusive clade. A revised diagnosis and more thorough understanding of the anatomy of Sarahsaurus aurifontanalis support the view that independent dispersal events were at least partly responsible for the recovery in North American vertebrate diversity following a major extinction event.
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Affiliation(s)
- Adam D. Marsh
- The Jackson School of Geosciences, University of Texas at Austin, Austin, Texas, United States of America
- Division of Science and Resource Management, Petrified Forest National Park, Arizona, United States of America
| | - Timothy B. Rowe
- The Jackson School of Geosciences, University of Texas at Austin, Austin, Texas, United States of America
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McPhee BW, Choiniere JN. The osteology of Pulanesaura eocollum: implications for the inclusivity of Sauropoda (Dinosauria). Zool J Linn Soc 2017. [DOI: 10.1093/zoolinnean/zlx074] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Blair W McPhee
- Departamento de Biologia, FFCLRP, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, Gauteng, South Africa
| | - Jonah N Choiniere
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, Gauteng, South Africa
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Bronzati M, Rauhut OWM. Braincase redescription of Efraasia minor Huene, 1908 (Dinosauria: Sauropodomorpha) from the Late Triassic of Germany, with comments on the evolution of the sauropodomorph braincase. Zool J Linn Soc 2017. [DOI: 10.1093/zoolinnean/zlx029] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Tschopp E, Tschopp FA, Mateus O. Overlap Indices: Tools to quantify the amount of anatomical overlap among groups of incomplete terminal taxa in phylogenetic analyses. ACTA ZOOL-STOCKHOLM 2017. [DOI: 10.1111/azo.12202] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Emanuel Tschopp
- Dipartimento di Scienze della Terra; Università degli Studi di Torino; Torino Italy
- GeoBioTec; Departamento de Ciências da Terra; Faculdade de Ciências e Tecnologia; Universidade Nova de Lisboa; Caparica Portugal
- Museu da Lourinhã; Lourinhã Portugal
| | | | - Octávio Mateus
- GeoBioTec; Departamento de Ciências da Terra; Faculdade de Ciências e Tecnologia; Universidade Nova de Lisboa; Caparica Portugal
- Museu da Lourinhã; Lourinhã Portugal
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Peyre de Fabrègues C, Allain R. New material and revision of Melanorosaurus thabanensis, a basal sauropodomorph from the Upper Triassic of Lesotho. PeerJ 2016; 4:e1639. [PMID: 26855874 PMCID: PMC4741091 DOI: 10.7717/peerj.1639] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 01/07/2016] [Indexed: 11/24/2022] Open
Abstract
Melanorosaurus is a genus of basal sauropodomorph that currently includes two species from Southern Africa. In this paper, we redescribe the holotype femur of Melanorosaurus thabanensis from the Elliot Formation of Lesotho, as well as associated remains. The stratigraphic position of this taxon is reviewed, and it is clear that it comes from the Lower Elliot Formation being, therefore, Late Triassic in age, and not Early Jurassic as originally described. The knowledge of the anatomy of the basal sauropodomorph of Thabana Morena is enhanced by the description of six new skeletal elements from the type locality. The femur and the ilium from Thabana Morena are diagnostic and characterized by unusual proportions. The first phylogenetic analysis including both this specimen and Melanorosaurus is conducted. This analysis leads to the conclusion that the femur described in the original publication of Melanorosaurus thabanensis can no longer be referred to Melanorosaurus. For these reasons, we hereby create Meroktenos gen. nov. to encompass Meroktenos thabanensis comb. nov.
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Affiliation(s)
- Claire Peyre de Fabrègues
- Muséum National d'Histoire Naturelle, Centre de Recherche sur la Paléobiodiversité et les Paléoenvironnements (CR2P, UMR 7207), Sorbonne Universités-MNHN, CNRS, UPMC , Paris , France
| | - Ronan Allain
- Muséum National d'Histoire Naturelle, Centre de Recherche sur la Paléobiodiversité et les Paléoenvironnements (CR2P, UMR 7207), Sorbonne Universités-MNHN, CNRS, UPMC , Paris , France
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