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Fawcett MJ, Lautenschlager S, Bestwick J, Butler RJ. Functional morphology of the Triassic apex predator Saurosuchus galilei (Pseudosuchia: Loricata) and convergence with a post-Triassic theropod dinosaur. Anat Rec (Hoboken) 2024; 307:549-565. [PMID: 37584310 DOI: 10.1002/ar.25299] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 07/11/2023] [Accepted: 07/13/2023] [Indexed: 08/17/2023]
Abstract
Pseudosuchian archosaurs, reptiles more closely related to crocodylians than to birds, exhibited high morphological diversity during the Triassic and are thus associated with hypotheses of high ecological diversity during this time. One example involves basal loricatans which are non-crocodylomorph pseudosuchians traditionally known as "rauisuchians." Their large size (5-8+ m long) and morphological similarities to post-Triassic theropod dinosaurs, including dorsoventrally deep skulls and serrated dentitions, suggest basal loricatans were apex predators. However, this hypothesis does not consider functional behaviors that can influence more refined roles of predators in their environment, for example, degree of carcass utilization. Here, we apply finite element analysis to a juvenile but three-dimensionally well-preserved cranium of the basal loricatan Saurosuchus galilei to investigate its functional morphology and to compare with stress distributions from the theropod Allosaurus fragilis to assess degrees of functional convergence between Triassic and post-Triassic carnivores. We find similar stress distributions and magnitudes between the two study taxa under the same functional simulations, indicating that Saurosuchus had a somewhat strong skull and thus exhibited some degree of functional convergence with theropods. However, Saurosuchus also had a weak bite for an animal of its size (1015-1885 N) that is broadly equivalent to the bite force of modern gharials (Gavialis gangeticus). We infer that Saurosuchus potentially avoided tooth-bone interactions and consumed the softer parts of carcasses, unlike theropods and other basal loricatans. This deduced feeding mode for Saurosuchus increases the known functional diversity of basal loricatans and highlights functional differences between Triassic and post-Triassic apex predators.
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Affiliation(s)
- Molly J Fawcett
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK
| | - Stephan Lautenschlager
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK
| | - Jordan Bestwick
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK
| | - Richard J Butler
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK
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Lei R, Tschopp E, Hendrickx C, Wedel MJ, Norell M, Hone DW. Bite and tooth marks on sauropod dinosaurs from the Morrison Formation. PeerJ 2023; 11:e16327. [PMID: 38025762 PMCID: PMC10655710 DOI: 10.7717/peerj.16327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 09/30/2023] [Indexed: 12/01/2023] Open
Abstract
Tooth-marked bones provide important evidence for feeding choices made by extinct carnivorous animals. In the case of the dinosaurs, most bite traces are attributed to the large and robust osteophagous tyrannosaurs, but those of other large carnivores remain underreported. Here we report on an extensive survey of the literature and some fossil collections cataloging a large number of sauropod bones (68) from the Upper Jurassic Morrison Formation of the USA that bear bite traces that can be attributed to theropods. We find that such bites on large sauropods, although less common than in tyrannosaur-dominated faunas, are known in large numbers from the Morrison Formation, and that none of the observed traces showed evidence of healing. The presence of tooth wear in non-tyrannosaur theropods further shows that they were biting into bone, but it remains difficult to assign individual bite traces to theropod taxa in the presence of multiple credible candidate biters. The widespread occurrence of bite traces without evidence of perimortem bites or healed bite traces, and of theropod tooth wear in Morrison Formation taxa suggests preferential feeding by theropods on juvenile sauropods, and likely scavenging of large-sized sauropod carcasses.
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Affiliation(s)
- Roberto Lei
- Università degli Studi di Modena e Reggio Emilia, Moderna, Italy
| | - Emanuel Tschopp
- American Museum of Natural History, New York, NY, USA
- Universität Hamburg, Hamburg, Germany
- GeoBioTec, Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
| | | | | | - Mark Norell
- American Museum of Natural History, New York, NY, USA
| | - David W.E. Hone
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, United Kingdom
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Bajpai S, Datta D, Pandey P, Ghosh T, Kumar K, Bhattacharya D. Fossils of the oldest diplodocoid dinosaur suggest India was a major centre for neosauropod radiation. Sci Rep 2023; 13:12680. [PMID: 37542094 PMCID: PMC10403599 DOI: 10.1038/s41598-023-39759-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 07/30/2023] [Indexed: 08/06/2023] Open
Abstract
The Early Jurassic and Cretaceous deposits of India are known for their diverse sauropod fauna, while little is known from the Middle and Late Jurassic. Here we report the first ever remains of a dicraeosaurid sauropod from India, Tharosaurus indicus gen. et sp. nov., from the Middle Jurassic (early-middle Bathonian) strata of Jaisalmer Basin, western India. Known from elements of the axial skeleton, the new taxon is phylogenetically among the earlier-diverging dicraeosaurids, and its stratigraphic age makes it the earliest known diplodocoid globally. Palaeobiogeographic considerations of Tharosaurus, seen in conjunction with the other Indian Jurassic sauropods, suggest that the new Indian taxon is a relic of a lineage that originated in India and underwent rapid dispersal across the rest of Pangaea. Here we emphasize the importance of Gondwanan India in tracing the origin and early evolutionary history of neosauropod dinosaurs.
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Affiliation(s)
- Sunil Bajpai
- Department of Earth Sciences, Indian Institute of Technology, Roorkee, Uttarakhand, 247667, India.
| | - Debajit Datta
- Department of Earth Sciences, Indian Institute of Technology, Roorkee, Uttarakhand, 247667, India.
| | - Pragya Pandey
- Geological Survey of India, Raipur, Chhattisgarh, 492010, India
| | - Triparna Ghosh
- Department of Earth Sciences, Indian Institute of Technology, Roorkee, Uttarakhand, 247667, India
- Geological Survey of India, Jaipur, Rajasthan, 302004, India
| | - Krishna Kumar
- Geological Survey of India, Jaipur, Rajasthan, 302004, India
| | - Debasish Bhattacharya
- Central Head Quarters, Geological Survey of India, Kolkata, West Bengal, 700091, India
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Poropat SF, Mannion PD, Rigby SL, Duncan RJ, Pentland AH, Bevitt JJ, Sloan T, Elliott DA. A nearly complete skull of the sauropod dinosaur Diamantinasaurus matildae from the Upper Cretaceous Winton Formation of Australia and implications for the early evolution of titanosaurs. ROYAL SOCIETY OPEN SCIENCE 2023; 10:221618. [PMID: 37063988 PMCID: PMC10090887 DOI: 10.1098/rsos.221618] [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: 12/21/2022] [Accepted: 03/21/2023] [Indexed: 06/19/2023]
Abstract
Titanosaurian sauropod dinosaurs were diverse and abundant throughout the Cretaceous, with a global distribution. However, few titanosaurian taxa are represented by multiple skeletons, let alone skulls. Diamantinasaurus matildae, from the lower Upper Cretaceous Winton Formation of Queensland, Australia, was heretofore represented by three specimens, including one that preserves a braincase and several other cranial elements. Herein, we describe a fourth specimen of Diamantinasaurus matildae that preserves a more complete skull-including numerous cranial elements not previously known for this taxon-as well as a partial postcranial skeleton. The skull of Diamantinasaurus matildae shows many similarities to that of the coeval Sarmientosaurus musacchioi from Argentina (e.g. quadratojugal with posterior tongue-like process; braincase with more than one ossified exit for cranial nerve V; compressed-cone-chisel-like teeth), providing further support for the inclusion of both taxa within the clade Diamantinasauria. The replacement teeth within the premaxilla of the new specimen are morphologically congruent with teeth previously attributed to Diamantinasaurus matildae, and Diamantinasauria more broadly, corroborating those referrals. Plesiomorphic characters of the new specimen include a sacrum comprising five vertebrae (also newly demonstrated in the holotype of Diamantinasaurus matildae), rather than the six or more that typify other titanosaurs. However, we demonstrate that there have been a number of independent acquisitions of a six-vertebrae sacrum among Somphospondyli and/or that there have been numerous reversals to a five-vertebrae sacrum, suggesting that sacral count is relatively plastic. Other newly identified plesiomorphic features include: the overall skull shape, which is more similar to brachiosaurids than 'derived' titanosaurs; anterior caudal centra that are amphicoelous, rather than procoelous; and a pedal phalangeal formula estimated as 2-2-3-2-0. These features are consistent with either an early-branching position within Titanosauria, or a position just outside the titanosaurian radiation, for Diamantinasauria, as indicated by alternative character weighting approaches applied in our phylogenetic analyses, and help to shed light on the early assembly of titanosaurian anatomy that has until now been obscured by a poor fossil record.
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Affiliation(s)
- Stephen F. Poropat
- Western Australian Organic and Isotope Geochemistry Centre, School of Earth and Planetary Science, Curtin University, Bentley, Western Australia 6102, Australia
- Australian Age of Dinosaurs Museum of Natural History, Winton, Queensland 4735, Australia
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia
| | - Philip D. Mannion
- Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, UK
| | - Samantha L. Rigby
- Australian Age of Dinosaurs Museum of Natural History, Winton, Queensland 4735, Australia
- School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia
| | - Ruairidh J. Duncan
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia
| | - Adele H. Pentland
- Australian Age of Dinosaurs Museum of Natural History, Winton, Queensland 4735, Australia
- School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia
| | - Joseph J. Bevitt
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Sydney, New South Wales 2234, Australia
| | - Trish Sloan
- Australian Age of Dinosaurs Museum of Natural History, Winton, Queensland 4735, Australia
| | - David A. Elliott
- Australian Age of Dinosaurs Museum of Natural History, Winton, Queensland 4735, Australia
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Gee BM, Kufner AM. Revision of the Late Triassic metoposaurid “ Metoposaurus” bakeri (Amphibia: Temnospondyli) from Texas, USA and a phylogenetic analysis of the Metoposauridae. PeerJ 2022. [DOI: 10.7717/peerj.14065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Metoposaurids are a clade of large-bodied temnospondyls commonly found in non-marine Late Triassic deposits across northern Pangea. Three taxa are known from North America: Anaschisma browni, Apachesaurus gregorii, and “Metoposaurus” bakeri. While the osteology of most metoposaurids has been recently revised, that of a few taxa, including “Metoposaurus” bakeri remains poorly characterized. This taxon was formally described in 1931 as “Buettneria bakeri,” and its taxonomy has remained in flux ever since then. “Metoposaurus” bakeri is the earliest appearing metoposaurid in North America (Carnian of Texas), and Metoposaurus has frequently been utilized as an index taxon of the Otischalkian estimated holochron (‘land vertebrate faunachron’) and for biostratigraphic correlations with other geographic regions. The taxonomy of this species is therefore relevant for both taxonomic experts and biostratigraphers. Here we redescribe all material from the type locality of “M.” bakeri, the Elkins Place bone bed, and perform a phylogenetic analysis using a revised matrix assembled from several previous studies. Anatomical comparisons and phylogenetic analyses do not support placement in either Metoposaurus, a taxon otherwise only found in Europe, or Anaschisma, the only other large-bodied taxon from North America. Therefore, we erect a new genus, Buettnererpeton gen. nov., to accommodate this species. Metoposaurus is consequently absent from North America, and this genus cannot be used in global biostratigraphy. Phylogenetic analyses provide evidence that the phylogeny of the Metoposauridae remains extremely labile, with drastic differences in topological resolution and structure being linked to just a handful of characters and scores. Metoposaurids’ morphological conservatism and the increased recognition of intraspecific variation thus continue to be major confounds to elucidating the evolutionary history of this clade.
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Affiliation(s)
- Bryan M. Gee
- Burke Museum and Department of Biology, University of Washington, Seattle, Washington, United States
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
| | - Aaron M. Kufner
- Department of Geoscience, University of Wisconsin, Madison, Wisconsin, United States
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Poropat SF, Frauenfelder TG, Mannion PD, Rigby SL, Pentland AH, Sloan T, Elliott DA. Sauropod dinosaur teeth from the lower Upper Cretaceous Winton Formation of Queensland, Australia and the global record of early titanosauriforms. ROYAL SOCIETY OPEN SCIENCE 2022; 9:220381. [PMID: 35845848 PMCID: PMC9277269 DOI: 10.1098/rsos.220381] [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: 04/12/2022] [Accepted: 06/20/2022] [Indexed: 06/15/2023]
Abstract
The Upper Cretaceous Winton Formation of Queensland, Australia, has produced several partial sauropod skeletons, but cranial remains-including teeth-remain rare. Herein, we present the first description of sauropod teeth from this formation, based on specimens from three separate sites. An isolated tooth and a dentary fragment from the Diamantinasaurus matildae type locality are considered to be referable to that titanosaurian taxon. A single tooth from the D. matildae referred specimen site is similarly regarded as being part of that individual. Seventeen teeth from a new site that are morphologically uniform, and similar to the teeth from the two Diamantinasaurus sites, are assigned to Diamantinasauria. All sauropod teeth recovered from the Winton Formation to date are compressed-cone-chisel-shaped, have low slenderness index values (2.00-2.88), are lingually curved at their apices, mesiodistally convex on their lingual surfaces, and lack prominent carinae and denticles. They are markedly different from the chisel-like teeth of derived titanosaurs, more closely resembling the teeth of early branching members of the titanosauriform radiation. This provides further support for a 'basal' titanosaurian position for Diamantinasauria. Scanning electron microscope microwear analysis of the wear facets of several teeth reveals more scratches than pits, implying that diamantinasaurians were mid-height (1-10 m) feeders. With a view to assessing the spatio-temporal distribution of sauropod tooth morphotypes before and after deposition of the Winton Formation, we provide a comprehensive continent-by-continent review of the early titanosauriform global record (Early to early Late Cretaceous). This indicates that throughout the Early-early Late Cretaceous, sauropod faunas transitioned from being quite diverse at higher phylogenetic levels and encompassing a range of tooth morphologies at the start of the Berriasian, to faunas comprising solely titanosaurs with limited dental variability by the end-Turonian. Furthermore, this review highlights the different ways in which this transition unfolded on each continent, including the earliest records of titanosaurs with narrow-crowned teeth on each continent.
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Affiliation(s)
- Stephen F. Poropat
- Australian Age of Dinosaurs Natural History Museum, The Jump-Up, Winton, Queensland 4735, Australia
- School of Science, Computing and Engineering Technologies, Swinburne University of Technology, John Street, Hawthorn, Victoria 3122, Australia
| | - Timothy G. Frauenfelder
- School of Environmental and Rural Science, University of New England, Armidale, New South Wales 2351, Australia
| | - Philip D. Mannion
- Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, UK
| | - Samantha L. Rigby
- Australian Age of Dinosaurs Natural History Museum, The Jump-Up, Winton, Queensland 4735, Australia
- School of Science, Computing and Engineering Technologies, Swinburne University of Technology, John Street, Hawthorn, Victoria 3122, Australia
| | - Adele H. Pentland
- Australian Age of Dinosaurs Natural History Museum, The Jump-Up, Winton, Queensland 4735, Australia
- School of Science, Computing and Engineering Technologies, Swinburne University of Technology, John Street, Hawthorn, Victoria 3122, Australia
| | - Trish Sloan
- Australian Age of Dinosaurs Natural History Museum, The Jump-Up, Winton, Queensland 4735, Australia
| | - David A. Elliott
- Australian Age of Dinosaurs Natural History Museum, The Jump-Up, Winton, Queensland 4735, Australia
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