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Bennion RF, Maxwell EE, Lambert O, Fischer V. Craniodental ecomorphology of the large Jurassic ichthyosaurian Temnodontosaurus. J Anat 2024; 244:22-41. [PMID: 37591692 PMCID: PMC10734653 DOI: 10.1111/joa.13939] [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: 04/02/2023] [Revised: 07/12/2023] [Accepted: 07/18/2023] [Indexed: 08/19/2023] Open
Abstract
Marine amniotes have played many crucial roles in ocean ecosystems since the Triassic, including predation at the highest trophic levels. One genus often placed into this guild is the large Early Jurassic neoichthyosaurian Temnodontosaurus, the only post-Triassic ichthyosaurian known with teeth which bear a distinct cutting edge or carina. This taxonomically problematic genus is currently composed of seven species which show a wide variety of skull and tooth morphologies. Here we assess the craniodental disparity in Temnodontosaurus using a series of functionally informative traits. We describe the range of tooth morphologies in the genus in detail, including the first examples of serrated carinae in ichthyosaurians. These consist of false denticles created by the interaction of enamel ridgelets with the carinal keel, as well as possible cryptic true denticles only visible using scanning electron microscopy. We also find evidence for heterodonty in the species T. platyodon, with unicarinate mesial teeth likely playing a role in prey capture and labiolingually compressed, bicarinate distal teeth likely involved in prey processing. This type of heterodonty appears to be convergent with a series of other marine amniotes including early cetaceans. Overall, the species currently referred to as the genus Temnodontosaurus show a range of craniodental configurations allowing prey to be captured and processed in different ways - for example, T. eurycephalus has a deep snout and relatively small bicarinate teeth likely specialised for increased wound infliction and grip-and-tear feeding, whereas T. platyodon has a more elongate yet robust snout and larger teeth and may be more adapted for grip-and-shear feeding. These results suggest the existence of niche partitioning at higher trophic levels in Early Jurassic ichthyosaurians and have implications for future work on the taxonomy of this wastebasket genus, as well as for research into the ecology of other extinct megapredatory marine tetrapods.
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Affiliation(s)
- R F Bennion
- Evolution & Diversity Dynamics Lab, Université de Liège, Liège, Belgium
- OD Earth and History of Life, Royal Belgian Institute of Natural Sciences, Brussels, Belgium
| | - E E Maxwell
- Staatliches Museum für Naturkunde Stuttgart, Stuttgart, Germany
| | - O Lambert
- OD Earth and History of Life, Royal Belgian Institute of Natural Sciences, Brussels, Belgium
| | - V Fischer
- Evolution & Diversity Dynamics Lab, Université de Liège, Liège, Belgium
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2
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Laboury A, Scheyer TM, Klein N, Stubbs TL, Fischer V. High phenotypic plasticity at the dawn of the eosauropterygian radiation. PeerJ 2023; 11:e15776. [PMID: 37671356 PMCID: PMC10476616 DOI: 10.7717/peerj.15776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 06/29/2023] [Indexed: 09/07/2023] Open
Abstract
The initial radiation of Eosauropterygia during the Triassic biotic recovery represents a key event in the dominance of reptiles secondarily adapted to marine environments. Recent studies on Mesozoic marine reptile disparity highlighted that eosauropterygians had their greatest morphological diversity during the Middle Triassic, with the co-occurrence of Pachypleurosauroidea, Nothosauroidea and Pistosauroidea, mostly along the margins of the Tethys Ocean. However, these previous studies quantitatively analysed the disparity of Eosauropterygia as a whole without focussing on Triassic taxa, thus limiting our understanding of their diversification and morphospace occupation during the Middle Triassic. Our multivariate morphometric analyses highlight a clearly distinct colonization of the ecomorphospace by the three clades, with no evidence of whole-body convergent evolution with the exception of the peculiar pistosauroid Wangosaurus brevirostris, which appears phenotypically much more similar to nothosauroids. This global pattern is mostly driven by craniodental differences and inferred feeding specializations. We also reveal noticeable regional differences among nothosauroids and pachypleurosauroids of which the latter likely experienced a remarkable diversification in the eastern Tethys during the Pelsonian. Our results demonstrate that the high phenotypic plasticity characterizing the evolution of the pelagic plesiosaurians was already present in their Triassic ancestors, casting eosauropterygians as particularly adaptable animals.
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Affiliation(s)
- Antoine Laboury
- Evolution & Diversity Dynamics Lab, Université de Liège, Liège, Belgium
| | | | - Nicole Klein
- Institute of Geosciences, Paleontology, University of Bonn, Bonn, Germany
| | - Thomas L. Stubbs
- School of Life, Health & Chemical Sciences, Open University, Milton Keynes, United Kingdom
| | - Valentin Fischer
- Evolution & Diversity Dynamics Lab, Université de Liège, Liège, Belgium
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3
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Grouping behavior in a Triassic marine apex predator. Curr Biol 2022; 32:5398-5405.e3. [PMID: 36538877 DOI: 10.1016/j.cub.2022.11.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 10/05/2022] [Accepted: 11/02/2022] [Indexed: 12/23/2022]
Abstract
Marine tetrapods occupy important roles in modern marine ecosystems and often gather in large aggregations driven by patchy prey distribution,1,2 social or reproductive behaviors,3,4 or oceanographic factors.5 Here, we show that similar grouping behaviors evolved in an early marine tetrapod lineage, documented by dozens of specimens of the giant ichthyosaur Shonisaurus in the Luning Formation in West Union Canyon, Nevada, USA.6,7 A concentration of at least seven skeletons closely preserved on a single bedding plane received the bulk of previous attention. However, many more specimens are preserved across ∼106 square meters and ∼200 stratigraphic meters of outcrop representing an estimated >105-6 years. Unlike other marine-tetrapod-rich deposits, this assemblage is essentially monotaxic; other vertebrate fossils are exceptionally scarce. Large individuals are disproportionately abundant, with the exception of multiple neonatal or embryonic specimens, indicating an unusual demographic composition apparently lacking intermediate-sized juveniles or subadults. Combined with geological evidence, our data suggest that dense aggregations of Shonisaurus inhabited this moderately deep, low-diversity, tropical marine environment for millennia during the latest Carnian Stage of the Late Triassic Period (237-227 Ma). Thus, philopatric grouping behavior in marine tetrapods, potentially linked to reproductive activity, has an antiquity of at least 230 million years.
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4
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Qiao Y, Liu J, Wolniewicz AS, Iijima M, Shen Y, Wintrich T, Li Q, Sander PM. A globally distributed durophagous marine reptile clade supports the rapid recovery of pelagic ecosystems after the Permo-Triassic mass extinction. Commun Biol 2022; 5:1242. [PMCID: PMC9663502 DOI: 10.1038/s42003-022-04162-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Accepted: 10/24/2022] [Indexed: 11/16/2022] Open
Abstract
AbstractMarine ecosystem recovery after the Permo-Triassic mass extinction (PTME) has been extensively studied in the shallow sea, but little is known about the nature of this process in pelagic ecosystems. Omphalosauridae, an enigmatic clade of open-water durophagous marine reptiles, potentially played an important role in the recovery, but their fragmentary fossils and uncertain phylogenetic position have hindered our understanding of their role in the process. Here we report the large basal ichthyosauriform Sclerocormus from the Early Triassic of China that clearly demonstrates an omphalosaurid affinity, allowing for the synonymy of the recently erected Nasorostra with Omphalosauridae. The skull also reveals the anatomy of the unique feeding apparatus of omphalosaurids, likely an adaptation for feeding on hard-shelled pelagic invertebrates, especially ammonoids. Morphofunctional analysis of jaws shows that omphalosaurids occupy the morphospace of marine turtles. Our discovery adds another piece of evidence for an explosive radiation of marine reptiles into the ocean in the Early Triassic and the rapid recovery of pelagic ecosystems after the PTME.
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5
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Cheng L, C. Moon B, Yan C, Motani R, Jiang D, An Z, Fang Z. The oldest record of Saurosphargiformes (Diapsida) from South China could fill an ecological gap in the Early Triassic biotic recovery. PeerJ 2022; 10:e13569. [PMID: 35855428 PMCID: PMC9288826 DOI: 10.7717/peerj.13569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 05/20/2022] [Indexed: 01/17/2023] Open
Abstract
Diversification following the end-Permian mass extinction marks the initiation of Mesozoic reptile dominance and of modern marine ecosystems, yet major clades are best known from the Middle Triassic suggesting delayed recovery, while Early Triassic localities produce poorly preserved specimens or have restricted diversity. Here we describe Pomolispondylus biani gen. et sp. nov. from the Early Triassic Nanzhang-Yuan'an Fauna of China assigned to Saurosphargiformes tax. nov., a clade known only from the Middle Triassic or later, which includes Saurosphargidae, and likely is the sister taxon to Sauropterygia. Pomolispondylus biani is allied to Saurosphargidae by the extended transverse processes of dorsal vertebrae and a low, table-like dorsal surface on the neural spine; however, it does not have the typical extensive osteoderms. Rather an unusual tuberous texture on the dorsal neural spine and rudimentary ossifications lateral to the gastralia are observed. Discovery of Pomolispondylus biani extends the known range of Saurosphargiformes and increases the taxic and ecological diversity of the Nanzhang-Yuan'an Fauna. Its small size fills a different ecological niche with respect to previously found species, but the overall food web remains notably different in structure to Middle Triassic and later ecosystems, suggesting this fauna represents a transitional stage during recovery rather than its endpoint.
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Affiliation(s)
- Long Cheng
- Hubei Key Laboratory of Paleontology and Geological Environment Evolution, Wuhan Center of China Geological Survey, Wuhan, P. R. China
| | - Benjamin C. Moon
- Palaeobiology Research Group, School of Earth Sciences, University of Bristol, Bristol, UK
| | - Chunbo Yan
- Hubei Key Laboratory of Paleontology and Geological Environment Evolution, Wuhan Center of China Geological Survey, Wuhan, P. R. China
| | - Ryosuke Motani
- University of California Davis, Department of Earth and Planetary Sciences, Davis, California, United States of America
| | - Dayong Jiang
- Peking University, Department of Geology and Geological Museum, Beijing, P. R. China
| | - Zhihui An
- Hubei Key Laboratory of Paleontology and Geological Environment Evolution, Wuhan Center of China Geological Survey, Wuhan, P. R. China
| | - Zichen Fang
- China University of Geoscience, Wuhan, P. R. China
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6
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Sander PM, Griebeler EM, Klein N, Juarbe JV, Wintrich T, Revell LJ, Schmitz L. Early giant reveals faster evolution of large body size in ichthyosaurs than in cetaceans. Science 2021; 374:eabf5787. [PMID: 34941418 DOI: 10.1126/science.abf5787] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- P Martin Sander
- Abteilung Paläontologie, Institut für Geowissenschaften, Universität Bonn, 53115 Bonn, Germany.,The Dinosaur Institute, Natural History Museum of Los Angeles County, Los Angeles, CA 90007, USA
| | - Eva Maria Griebeler
- Institut für Organismische und Molekulare Evolutionsbiologie, Evolutionäre Ökologie, Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
| | - Nicole Klein
- Abteilung Paläontologie, Institut für Geowissenschaften, Universität Bonn, 53115 Bonn, Germany
| | - Jorge Velez Juarbe
- Department of Mammalogy, Natural History Museum of Los Angeles County, Los Angeles, CA 90007, USA
| | - Tanja Wintrich
- Abteilung Paläontologie, Institut für Geowissenschaften, Universität Bonn, 53115 Bonn, Germany.,Anatomisches Institut, Universität Bonn, 53115 Bonn, Germany
| | - Liam J Revell
- Department of Biology, University of Massachusetts Boston, Boston, MA 02125, USA.,Universidad Católica de la Santísima Concepción, Concepción, Chile
| | - Lars Schmitz
- The Dinosaur Institute, Natural History Museum of Los Angeles County, Los Angeles, CA 90007, USA.,W.M. Keck Science Department of Claremont McKenna, Scripps, and Pitzer Colleges, Claremont, CA 91711, USA
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7
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Bindellini G, Wolniewicz AS, Miedema F, Scheyer TM, Dal Sasso C. Cranial anatomy of Besanosaurus leptorhynchus Dal Sasso & Pinna, 1996 (Reptilia: Ichthyosauria) from the Middle Triassic Besano Formation of Monte San Giorgio, Italy/Switzerland: taxonomic and palaeobiological implications. PeerJ 2021; 9:e11179. [PMID: 33996277 PMCID: PMC8106916 DOI: 10.7717/peerj.11179] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 03/08/2021] [Indexed: 12/20/2022] Open
Abstract
Besanosaurus leptorhynchus Dal Sasso & Pinna, 1996 was described on the basis of a single fossil excavated near Besano (Italy) nearly three decades ago. Here, we re-examine its cranial osteology and assign five additional specimens to B. leptorhynchus, four of which were so far undescribed. All of the referred specimens were collected from the Middle Triassic outcrops of the Monte San Giorgio area (Italy/Switzerland) and are housed in various museum collections in Europe. The revised diagnosis of the taxon includes the following combination of cranial characters: extreme longirostry; an elongate frontal not participating in the supratemporal fenestra; a prominent 'triangular process' of the quadrate; a caudoventral exposure of the postorbital on the skull roof; a prominent coronoid (preglenoid) process of the surangular; tiny conical teeth with coarsely-striated crown surfaces and deeply-grooved roots; mesial maxillary teeth set in sockets; distal maxillary teeth set in a short groove. All these characters are shared with the holotype of Mikadocephalus gracilirostris Maisch & Matzke, 1997, which we consider as a junior synonym of B. leptorhynchus. An updated phylogenetic analysis, which includes revised scores for B. leptorhynchus and several other shastasaurids, recovers B. leptorhynchus as a basal merriamosaurian, but it is unclear if Shastasauridae form a clade, or represent a paraphyletic group. The inferred body length of the examined specimens ranges from 1 m to about 8 m. The extreme longirostry suggests that B. leptorhynchus primarily fed on small and elusive prey, feeding lower in the food web than an apex predator: a novel ecological specialisation never reported before the Anisian in a large diapsid. This specialization might have triggered an increase of body size and helped to maintain low competition among the diverse ichthyosaur fauna of the Besano Formation.
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Affiliation(s)
- Gabriele Bindellini
- Dipartimento di Scienze della Terra “Ardito Desio”, Università degli Studi di Milano, Milano, Italy
| | | | - Feiko Miedema
- Staatliches Museum für Naturkunde Stuttgart, Stuttgart, Germany
- Paläontologisches Institut und Museum, Universität Zürich, Zürich, Switzerland
| | - Torsten M. Scheyer
- Paläontologisches Institut und Museum, Universität Zürich, Zürich, Switzerland
| | - Cristiano Dal Sasso
- Sezione di Paleontologia dei Vertebrati, Museo di Storia Naturale di Milano, Milano, Italy
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8
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Jiang DY, Motani R, Tintori A, Rieppel O, Ji C, Zhou M, Wang X, Lu H, Li ZG. Evidence Supporting Predation of 4-m Marine Reptile by Triassic Megapredator. iScience 2020; 23:101347. [PMID: 32822565 PMCID: PMC7520894 DOI: 10.1016/j.isci.2020.101347] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 06/09/2020] [Accepted: 07/04/2020] [Indexed: 11/28/2022] Open
Abstract
Air-breathing marine predators have been essential components of the marine ecosystem since the Triassic. Many of them are considered the apex predators but without direct evidence-dietary inferences are usually based on circumstantial evidence, such as tooth shape. Here we report a fossil that likely represents the oldest evidence for predation on megafauna, i.e., animals equal to or larger than humans, by marine tetrapods-a thalattosaur (∼4 m in total length) in the stomach of a Middle Triassic ichthyosaur (∼5 m). The predator has grasping teeth yet swallowed the body trunk of the prey in one to several pieces. There were many more Mesozoic marine reptiles with similar grasping teeth, so megafaunal predation was likely more widespread than presently conceived. Megafaunal predation probably started nearly simultaneously in multiple lineages of marine reptiles in the Illyrian (about 242-243 million years ago).
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Affiliation(s)
- Da-Yong Jiang
- Laboratory of Orogenic Belt and Crustal Evolution, Ministry of Education; Department of Geology and Geological Museum, School of Earth and Space Sciences, Peking University, Yiheyuan Street. 5, Beijing 100871, People's Republic of China
| | - Ryosuke Motani
- Department of Earth and Planetary Sciences, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Andrea Tintori
- Dipartimento di Scienze della Terra, Università degli Studi di Milano, Via Mangiagalli, 34-20133 Milano, Italy
| | - Olivier Rieppel
- Integrative Research Center, The Field Museum, Chicago, IL 60605-2496, USA
| | - Cheng Ji
- Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Beijing East Road 39, Nanjing, Jiangsu 210008, People's Republic of China
| | - Min Zhou
- Laboratory of Orogenic Belt and Crustal Evolution, Ministry of Education; Department of Geology and Geological Museum, School of Earth and Space Sciences, Peking University, Yiheyuan Street. 5, Beijing 100871, People's Republic of China
| | - Xue Wang
- Laboratory of Orogenic Belt and Crustal Evolution, Ministry of Education; Department of Geology and Geological Museum, School of Earth and Space Sciences, Peking University, Yiheyuan Street. 5, Beijing 100871, People's Republic of China
| | - Hao Lu
- Laboratory of Orogenic Belt and Crustal Evolution, Ministry of Education; Department of Geology and Geological Museum, School of Earth and Space Sciences, Peking University, Yiheyuan Street. 5, Beijing 100871, People's Republic of China
| | - Zhi-Guang Li
- The Geoscience Museum, Hebei GEO University, No. 136 East Huai'an Road, Shijiazhuang, Hebei 050031, People's Republic of China
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9
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Moon BC, Stubbs TL. Early high rates and disparity in the evolution of ichthyosaurs. Commun Biol 2020; 3:68. [PMID: 32054967 PMCID: PMC7018711 DOI: 10.1038/s42003-020-0779-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 01/07/2020] [Indexed: 12/02/2022] Open
Abstract
How clades diversify early in their history is integral to understanding the origins of biodiversity and ecosystem recovery following mass extinctions. Moreover, diversification can represent evolutionary opportunities and pressures following ecosystem changes. Ichthyosaurs, Mesozoic marine reptiles, appeared after the end-Permian mass extinction and provide opportunities to assess clade diversification in a changed world. Using recent cladistic data, skull length data, and the most complete phylogenetic trees to date for the group, we present a combined disparity, morphospace, and evolutionary rates analysis that reveals the tempo and mode of ichthyosaur morphological evolution through 160 million years. Ichthyosaur evolution shows an archetypal early burst trend, driven by ecological opportunity in Triassic seas, and an evolutionary bottleneck leading to a long-term reduction in evolutionary rates and disparity. This is represented consistently across all analytical methods by a Triassic peak in ichthyosaur disparity and evolutionary rates, and morphospace separation between Triassic and post-Triassic taxa.
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Affiliation(s)
- Benjamin C Moon
- Palaeobiology Research Group, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK.
| | - Thomas L Stubbs
- Palaeobiology Research Group, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
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10
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Li Q, Liu J. An Early Triassic sauropterygian and associated fauna from South China provide insights into Triassic ecosystem health. Commun Biol 2020; 3:63. [PMID: 32047220 PMCID: PMC7012838 DOI: 10.1038/s42003-020-0778-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 01/15/2020] [Indexed: 11/09/2022] Open
Abstract
The timing and pattern of biotic recovery from the Permo-Triassic Mass Extinction remains elusive. Here we report new material of the Early Triassic sauropterygian Lariosaurus sanxiaensis and associated fauna from the Jialingjiang Formation in Hubei Province, South China. Phylogenetic analysis based on a novel data matrix of sauropterygians recognizes L. sanxiaensis as a basal nothosaur. Stratigraphic congruence analysis shows that the new phylogenetic consensus tree matches to the stratigraphic distribution of sauropterygians very well. The diversified reptilian fauna and inferred simple food web in the Nanzhang-Yuan'an fauna where L. sanxiaensis was discovered suggest that the Triassic biotic recovery adopted a top-down pattern, in contrast to the prevailing view. Comparison with the Middle Triassic Luoping biota from the same carbonate platform suggests that the Triassic biotic recovery is delayed and healthy ecosystems were not established until the Middle Triassic in South China.
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Affiliation(s)
- Qiang Li
- School of Resources and Environmental Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Jun Liu
- School of Resources and Environmental Engineering, Hefei University of Technology, Hefei, 230009, China.
- Institute of Geosciences, University of Bonn, Bonn, 53115, Germany.
- Nanjing Institute of Geology and Palaeontology, Nanjing, 210008, China.
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11
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Gutarra S, Moon BC, Rahman IA, Palmer C, Lautenschlager S, Brimacombe AJ, Benton MJ. Effects of body plan evolution on the hydrodynamic drag and energy requirements of swimming in ichthyosaurs. Proc Biol Sci 2019; 286:20182786. [PMID: 30836867 PMCID: PMC6458325 DOI: 10.1098/rspb.2018.2786] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [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: 02/11/2019] [Indexed: 01/05/2023] Open
Abstract
Ichthyosaurs are an extinct group of fully marine tetrapods that were well adapted to aquatic locomotion. During their approximately 160 Myr existence, they evolved from elongate and serpentine forms into stockier, fish-like animals, convergent with sharks and dolphins. Here, we use computational fluid dynamics (CFD) to quantify the impact of this transition on the energy demands of ichthyosaur swimming for the first time. We run computational simulations of water flow using three-dimensional digital models of nine ichthyosaurs and an extant functional analogue, a bottlenose dolphin, providing the first quantitative evaluation of ichthyosaur hydrodynamics across phylogeny. Our results show that morphology did not have a major effect on the drag coefficient or the energy cost of steady swimming through geological time. We show that even the early ichthyosaurs produced low levels of drag for a given volume, comparable to those of a modern dolphin, and that deep 'torpedo-shaped' bodies did not reduce the cost of locomotion. Our analysis also provides important insight into the choice of scaling parameters for CFD applied to swimming mechanics, and underlines the great influence of body size evolution on ichthyosaur locomotion. A combination of large bodies and efficient swimming modes lowered the cost of steady swimming as ichthyosaurs became increasingly adapted to a pelagic existence.
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Affiliation(s)
- Susana Gutarra
- School of Earth Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Benjamin C. Moon
- School of Earth Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Imran A. Rahman
- Oxford University Museum of Natural History, Parks Road, Oxford OX1 3PW, UK
| | - Colin Palmer
- School of Earth Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Stephan Lautenschlager
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Alison J. Brimacombe
- School of Earth Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Michael J. Benton
- School of Earth Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
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12
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Pardo-Pérez JM, Kear BP, Mallison H, Gómez M, Moroni M, Maxwell EE. Pathological survey on Temnodontosaurus from the Early Jurassic of southern Germany. PLoS One 2018; 13:e0204951. [PMID: 30356279 PMCID: PMC6200200 DOI: 10.1371/journal.pone.0204951] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 09/16/2018] [Indexed: 11/19/2022] Open
Abstract
Paleopathologies document skeletal damage in extinct organisms and can be used to infer the causes of injury, as well as aspects of related biology, ecology and behavior. To date, few studies have been undertaken on Jurassic marine reptiles, while ichthyosaur pathologies in particular have never been systematically evaluated. Here we survey 41 specimens of the apex predator ichthyosaur Temnodontosaurus from the Early Jurassic of southern Germany in order to document the range and absolute frequency of pathologies observed in this taxon as a function of the number of specimens examined. According to our analysis, most observed pathologies in Temnodontosaurus are force-induced traumas with signs of healing, possibly inflicted during aggressive interactions with conspecifics. When the material is preserved, broken ribs are correlated in most of the cases with traumas elsewhere in the skeleton such as cranial injuries. The range of cranial pathologies in Temnodontosaurus is similar to those reported for extinct cetaceans and mosasaurs, which were interpreted as traces of aggressive encounters. Nevertheless, Temnodontosaurus differs from these other marine amniotes in the absence of pathologies in the vertebral column, consistent with the pattern previously documented in ichthyosaurs. We did not detect any instances of avascular necrosis in Temnodontosaurus from southern Germany, which may reflect a shallow diving life style. This study is intended to provide baseline data for the various types of observed pathologies in large ichthyosaurs occupying the 'apex predator' niche, and potentially clarifies aspects of species-specific behavior relative to other ichthyosaurs and marine amniotes.
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Affiliation(s)
- Judith M. Pardo-Pérez
- Staatliches Museum für Naturkunde Stuttgart, Stuttgart, Germany
- Vicerrectoría de Investigación y Postgrado, Universidad de Magallanes, Punta Arenas, Chile
| | | | | | - Marcelo Gómez
- Escuela de Medicina Veterinaria, Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Campus Isla Teja, Valdivia, Chile
| | - Manuel Moroni
- Escuela de Medicina Veterinaria, Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Campus Isla Teja, Valdivia, Chile
| | - Erin E. Maxwell
- Staatliches Museum für Naturkunde Stuttgart, Stuttgart, Germany
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13
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Palaeobiology of red and white blood cell-like structures, collagen and cholesterol in an ichthyosaur bone. Sci Rep 2017; 7:13776. [PMID: 29061985 PMCID: PMC5653768 DOI: 10.1038/s41598-017-13873-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 10/03/2017] [Indexed: 11/24/2022] Open
Abstract
Carbonate concretions are known to contain well-preserved fossils and soft tissues. Recently, biomolecules (e.g. cholesterol) and molecular fossils (biomarkers) were also discovered in a 380 million-year-old concretion, revealing their importance in exceptional preservation of biosignatures. Here, we used a range of microanalytical techniques, biomarkers and compound specific isotope analyses to report the presence of red and white blood cell-like structures as well as platelet-like structures, collagen and cholesterol in an ichthyosaur bone encapsulated in a carbonate concretion from the Early Jurassic (~182.7 Ma). The red blood cell-like structures are four to five times smaller than those identified in modern organisms. Transmission electron microscopy (TEM) analysis revealed that the red blood cell-like structures are organic in composition. We propose that the small size of the blood cell-like structures results from an evolutionary adaptation to the prolonged low oxygen atmospheric levels prevailing during the 70 Ma when ichthyosaurs thrived. The δ13C of the ichthyosaur bone cholesterol indicates that it largely derives from a higher level in the food chain and is consistent with a fish and cephalopod diet. The combined findings above demonstrate that carbonate concretions create isolated environments that promote exceptional preservation of fragile tissues and biomolecules.
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Price SA, Schmitz L. A promising future for integrative biodiversity research: an increased role of scale-dependency and functional biology. Philos Trans R Soc Lond B Biol Sci 2016; 371:20150228. [PMID: 26977068 DOI: 10.1098/rstb.2015.0228] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Studies into the complex interaction between an organism and changes to its biotic and abiotic environment are fundamental to understanding what regulates biodiversity. These investigations occur at many phylogenetic, temporal and spatial scales and within a variety of biological and geological disciplines but often in relative isolation. This issue focuses on what can be achieved when ecological mechanisms are integrated into analyses of deep-time biodiversity patterns through the union of fossil and extant data and methods. We expand upon this perspective to argue that, given its direct relevance to the current biodiversity crisis, greater integration is needed across biodiversity research. We focus on the need to understand scaling effects, how lower-level ecological and evolutionary processes scale up and vice versa, and the importance of incorporating functional biology. Placing function at the core of biodiversity research is fundamental, as it establishes how an organism interacts with its abiotic and biotic environment and it is functional diversity that ultimately determines important ecosystem processes. To achieve full integration, concerted and ongoing efforts are needed to build a united and interactive community of biodiversity researchers, with education and interdisciplinary training at its heart.
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Affiliation(s)
- S A Price
- Department of Evolution & Ecology, University of California Davis, 1 Shields Avenue, Davis, CA 95616, USA
| | - L Schmitz
- W.M. Keck Science Department, Claremont McKenna, Pitzer, and Scripps Colleges, 925 North Mills Avenue, Claremont, CA 91711, USA
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Jiang DY, Motani R, Huang JD, Tintori A, Hu YC, Rieppel O, Fraser NC, Ji C, Kelley NP, Fu WL, Zhang R. A large aberrant stem ichthyosauriform indicating early rise and demise of ichthyosauromorphs in the wake of the end-Permian extinction. Sci Rep 2016; 6:26232. [PMID: 27211319 PMCID: PMC4876504 DOI: 10.1038/srep26232] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 04/29/2016] [Indexed: 11/30/2022] Open
Abstract
Contrary to the fast radiation of most metazoans after the end-Permian mass extinction, it is believed that early marine reptiles evolved slowly during the same time interval. However, emerging discoveries of Early Triassic marine reptiles are questioning this traditional view. Here we present an aberrant basal ichthyosauriform with a hitherto unknown body design that suggests a fast radiation of early marine reptiles. The new species is larger than coeval marine reptiles and has an extremely small head and a long tail without a fluke. Its heavily-built body bears flattened and overlapping gastral elements reminiscent of hupehsuchians. A phylogenetic analysis places the new species at the base of ichthyosauriforms, as the sister taxon of Cartorhynchus with which it shares a short snout with rostrally extended nasals. It now appears that ichthyosauriforms evolved rapidly within the first one million years of their evolution, in the Spathian (Early Triassic), and their true diversity has yet to be fully uncovered. Early ichthyosauromorphs quickly became extinct near the Early-Middle Triassic boundary, during the last large environmental perturbation after the end-Permian extinction involving redox fluctuations, sea level changes and volcanism. Marine reptile faunas shifted from ichthyosauromorph-dominated to sauropterygian-dominated composition after the perturbation.
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Affiliation(s)
- Da-Yong Jiang
- Laboratory of Orogenic Belt and Crustal Evolution, Ministry of Education; Department of Geology and Geological Museum, Peking University, Yiheyuan Street. 5, Beijing 100871, People's Republic of China
| | - Ryosuke Motani
- Department of Earth and Planetary Sciences, University of California, Davis, One Shields Avenue, Davis, California 95616, United States of America
| | - Jian-Dong Huang
- Department of Research, Anhui Geological Museum, Jiahe Road 999, Hefei, Anhui 230031, People's Republic of China
| | - Andrea Tintori
- Dipartimento di Scienze della Terra, Università degli Studi di Milano, Via Mangiagalli 34-20133 Milano, Italy
| | - Yuan-Chao Hu
- Department of Research, Anhui Geological Museum, Jiahe Road 999, Hefei, Anhui 230031, People's Republic of China
| | - Olivier Rieppel
- Center of Integrative Research, The Field Museum, Chicago, IL 60605-2496, United States of America
| | - Nicholas C Fraser
- National Museums Scotland, Chambers Street, Edinburgh EH1 1JF, United Kingdom
| | - Cheng Ji
- Key Laboratory of Economic Stratigraphy and Palaeogeography, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, 39 East Beijing Road, Nanjing 210008, People's Republic of China
| | - Neil P Kelley
- Smithsonian Institution, National Museum of Natural History, Washington, DC 20560-0121, United States of America
| | - Wan-Lu Fu
- Laboratory of Orogenic Belt and Crustal Evolution, Ministry of Education; Department of Geology and Geological Museum, Peking University, Yiheyuan Street. 5, Beijing 100871, People's Republic of China
| | - Rong Zhang
- Department of Research, Anhui Geological Museum, Jiahe Road 999, Hefei, Anhui 230031, People's Republic of China
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Chun L, Rieppel O, Long C, Fraser NC. The earliest herbivorous marine reptile and its remarkable jaw apparatus. SCIENCE ADVANCES 2016; 2:e1501659. [PMID: 27386529 PMCID: PMC4928886 DOI: 10.1126/sciadv.1501659] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 04/07/2016] [Indexed: 06/06/2023]
Abstract
Newly discovered fossils of the Middle Triassic reptile Atopodentatus unicus call for a radical reassessment of its feeding behavior. The skull displays a pronounced hammerhead shape that was hitherto unknown. The long, straight anterior edges of both upper and lower jaws were lined with batteries of chisel-shaped teeth, whereas the remaining parts of the jaw rami supported densely packed needle-shaped teeth forming a mesh. The evidence indicates a novel feeding mechanism wherein the chisel-shaped teeth were used to scrape algae off the substrate, and the plant matter that was loosened was filtered from the water column through the more posteriorly positioned tooth mesh. This is the oldest record of herbivory within marine reptiles.
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Affiliation(s)
- Li Chun
- Institute of Vertebrate Paleontology and Paleoanthropology, 142 Xizhimenwai Street, Beijing 100044, People’s Republic of China
| | - Olivier Rieppel
- Field Museum of Natural History, 1400 South Lake Shore Drive, Chicago, IL 60605, USA
| | - Cheng Long
- Wuhan Centre of China Geological Survey, Wuhan, Hubei 430023, People’s Republic of China
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Kelley NP, Motani R, Embree P, Orchard MJ. A new Lower Triassic ichthyopterygian assemblage from Fossil Hill, Nevada. PeerJ 2016; 4:e1626. [PMID: 26855868 PMCID: PMC4741062 DOI: 10.7717/peerj.1626] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 01/05/2016] [Indexed: 11/20/2022] Open
Abstract
We report a new ichthyopterygian assemblage from Lower Triassic horizons of the Prida Formation at Fossil Hill in central Nevada. Although fragmentary, the specimens collected so far document a diverse fauna. One partial jaw exhibits isodont dentition with blunt tipped, mesiodistally compressed crowns and striated enamel. These features are shared with the Early Triassic genus Utatsusaurus known from coeval deposits in Japan and British Columbia. An additional specimen exhibits a different dentition characterized by relatively small, rounded posterior teeth resembling other Early Triassic ichthyopterygians, particularly Grippia. This Nevada assemblage marks a southward latitudinal extension for Early Triassic ichthyopterygians along the eastern margin of Panthalassa and indicates repeated trans-hemispheric dispersal events in Early Triassic ichthyopterygians.
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Affiliation(s)
- Neil P Kelley
- Department of Paleobiology, National Museum of Natural History, Smithsonian, Washington, District of Columbia, United States; Department of Earth and Planetary Sciences, University of California, Davis, Davis, California, United States
| | - Ryosuke Motani
- Department of Earth and Planetary Sciences, University of California, Davis , Davis, California , United States
| | | | - Michael J Orchard
- Natural Resources Canada-Geological Survey of Canada , Vancouver, British Columbia , Canada
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19
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Vermeij GJ. Gigantism and Its Implications for the History of Life. PLoS One 2016; 11:e0146092. [PMID: 26771527 PMCID: PMC4714876 DOI: 10.1371/journal.pone.0146092] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 12/14/2015] [Indexed: 11/19/2022] Open
Abstract
Gigantism-very large body size-is an ecologically important trait associated with competitive superiority. Although it has been studied in particular cases, the general conditions for the evolution and maintenance of gigantism remain obscure. I compiled sizes and dates for the largest species in 3 terrestrial and 7 marine trophic and habitat categories of animals from throughout the Phanerozoic. The largest species (global giants) in all categories are of post-Paleozoic age. Gigantism at this level appeared tens to hundreds of millions of years after mass extinctions and long after the origins of clades in which it evolved. Marine gigantism correlates with high planktic or seafloor productivity, but on land the correspondence between productivity and gigantism is weak at best. All global giants are aerobically active animals, not gentle giants with low metabolic demands. Oxygen concentration in the atmosphere correlates with gigantism in the Paleozoic but not thereafter, likely because of the elaboration of efficient gas-exchange systems in clades containing giants. Although temperature and habitat size are important in the evolution of very large size in some cases, the most important (and rare) enabling circumstance is a highly developed ecological infrastructure in which essential resources are abundant and effectively recycled and reused, permitting activity levels to increase and setting the stage for gigantic animals to evolve. Gigantism as a hallmark of competitive superiority appears to have lost its luster on land after the Mesozoic in favor of alternative means of achieving dominance, especially including social organization and coordinated food-gathering.
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Affiliation(s)
- Geerat J. Vermeij
- Department of Earth and Planetary Sciences, University of California, One Shields Avenue, Davis, California, 95616, United States of America
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20
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Sallan L, Galimberti AK. Body-size reduction in vertebrates following the end-Devonian mass extinction. Science 2015; 350:812-5. [DOI: 10.1126/science.aac7373] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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21
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Kelley NP, Pyenson ND. Evolutionary innovation and ecology in marine tetrapods from the Triassic to the Anthropocene. Science 2015; 348:aaa3716. [DOI: 10.1126/science.aaa3716] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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22
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Motani R, Chen XH, Jiang DY, Cheng L, Tintori A, Rieppel O. Lunge feeding in early marine reptiles and fast evolution of marine tetrapod feeding guilds. Sci Rep 2015; 5:8900. [PMID: 25754468 PMCID: PMC4354009 DOI: 10.1038/srep08900] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 02/02/2015] [Indexed: 12/04/2022] Open
Abstract
Traditional wisdom holds that biotic recovery from the end-Permian extinction was slow and gradual, and was not complete until the Middle Triassic. Here, we report that the evolution of marine predator feeding guilds, and their trophic structure, proceeded faster. Marine reptile lineages with unique feeding adaptations emerged during the Early Triassic (about 248 million years ago), including the enigmatic Hupehsuchus that possessed an unusually slender mandible. A new specimen of this genus reveals a well-preserved palate and mandible, which suggest that it was a rare lunge feeder as also occurs in rorqual whales and pelicans. The diversity of feeding strategies among Triassic marine tetrapods reached their peak in the Early Triassic, soon after their first appearance in the fossil record. The diet of these early marine tetrapods most likely included soft-bodied animals that are not preserved as fossils. Early marine tetrapods most likely introduced a new trophic mechanism to redistribute nutrients to the top 10 m of the sea, where the primary productivity is highest. Therefore, a simple recovery to a Permian-like trophic structure does not explain the biotic changes seen after the Early Triassic.
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Affiliation(s)
- Ryosuke Motani
- Department of Earth and Planetary Sciences, University of California, Davis, One Shields Avenue, Davis, California 95616, U.S.A
| | - Xiao-hong Chen
- Wuhan Centre of China Geological Survey, Wuhan, Hubei 430023, P. R. China
| | - Da-yong Jiang
- Laboratory of Orogenic Belt and Crustal Evolution, Ministry of Education; Department of Geology and Geological Museum, Peking University, Yiheyuan Street. 5, Beijing 100871, P.R. China
| | - Long Cheng
- Wuhan Centre of China Geological Survey, Wuhan, Hubei 430023, P. R. China
| | - Andrea Tintori
- Dipartimento di Scienze della Terra, Università degli Studi di Milano, Via Mangiagalli 34-20133 Milano, Italy
| | - Olivier Rieppel
- Center of Integrative Research, The Field Museum, Chicago. IL 60605-2496, U.S.A
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Liu J, Hu SX, Rieppel O, Jiang DY, Benton MJ, Kelley NP, Aitchison JC, Zhou CY, Wen W, Huang JY, Xie T, Lv T. A gigantic nothosaur (Reptilia: Sauropterygia) from the Middle Triassic of SW China and its implication for the Triassic biotic recovery. Sci Rep 2014; 4:7142. [PMID: 25429609 PMCID: PMC4245812 DOI: 10.1038/srep07142] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 10/20/2014] [Indexed: 11/28/2022] Open
Abstract
The presence of gigantic apex predators in the eastern Panthalassic and western Tethyan oceans suggests that complex ecosystems in the sea had become re-established in these regions at least by the early Middle Triassic, after the Permian-Triassic mass extinction (PTME). However, it is not clear whether oceanic ecosystem recovery from the PTME was globally synchronous because of the apparent lack of such predators in the eastern Tethyan/western Panthalassic region prior to the Late Triassic. Here we report a gigantic nothosaur from the lower Middle Triassic of Luoping in southwest China (eastern Tethyan ocean), which possesses the largest known lower jaw among Triassic sauropterygians. Phylogenetic analysis suggests parallel evolution of gigantism in Triassic sauropterygians. Discovery of this gigantic apex predator, together with associated diverse marine reptiles and the complex food web, indicates global recovery of shallow marine ecosystems from PTME by the early Middle Triassic.
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Affiliation(s)
- Jun Liu
- 1] Chengdu Center, China Geological Survey, Chengdu 610081, China [2] School of Resources and Environmental Engineering, Hefei University of Technology, Hefei 230009, China [3] State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, CAS, Nanjing 210008, China
| | - Shi-Xue Hu
- Chengdu Center, China Geological Survey, Chengdu 610081, China
| | - Olivier Rieppel
- Center of Integrative Research, The Field Museum, Chicago, IL 60605-2496, USA
| | - Da-Yong Jiang
- Department of Geology and Geological Museum, Peking University, Beijing 100871, China
| | - Michael J Benton
- School of Earth Sciences, University of Bristol, Bristol, BS8 1RJ, UK
| | - Neil P Kelley
- Department of Paleobiology, National Museum of Natural History, Washington DC 20013, USA
| | | | - Chang-Yong Zhou
- Chengdu Center, China Geological Survey, Chengdu 610081, China
| | - Wen Wen
- Chengdu Center, China Geological Survey, Chengdu 610081, China
| | - Jin-Yuan Huang
- Chengdu Center, China Geological Survey, Chengdu 610081, China
| | - Tao Xie
- Chengdu Center, China Geological Survey, Chengdu 610081, China
| | - Tao Lv
- Chengdu Center, China Geological Survey, Chengdu 610081, China
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24
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Fischer V, Cappetta H, Vincent P, Garcia G, Goolaerts S, Martin JE, Roggero D, Valentin X. Ichthyosaurs from the French Rhaetian indicate a severe turnover across the Triassic-Jurassic boundary. Naturwissenschaften 2014; 101:1027-40. [PMID: 25256640 DOI: 10.1007/s00114-014-1242-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Revised: 09/12/2014] [Accepted: 09/15/2014] [Indexed: 11/29/2022]
Abstract
Mesozoic marine reptiles went through a severe turnover near the end of the Triassic. Notably, an important extinction event affected ichthyosaurs, sweeping a large part of the group. This crisis is, however, obscured by an extremely poor fossil record and is regarded as protracted over the entire Norian-earliest Jurassic interval, for the lack of a more precise scenario. The iconic whale-sized shastasaurid ichthyosaurs are regarded as early victims of this turnover, disappearing by the middle Norian. Here we evaluate the pattern of this turnover among ichthyosaurs by analysing the faunal record of two Rhaetian localities. One locality is Autun, eastern France; we rediscovered in this material the holotypes or partial 'type' series of Rachitrema pellati, Actiosaurus gaudryi, Ichthyosaurus rheticus, Ichthyosaurus carinatus and Plesiosaurus bibractensis; a revised taxonomic scheme is proposed. The second assemblage comes from a new locality: Cuers, southeastern France. Both these assemblages provide several lines of evidence for the presence of shastasaurid-like ichthyosaurs in the Rhaetian of Europe. These occurrences suggest that both the demise of shastasaurids and the sudden radiation of neoichthyosaurians occurred within a short time window; this turnover appears not only more abrupt but also more complex than previously postulated and adds a new facet of the end-Triassic mass extinction.
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Affiliation(s)
- Valentin Fischer
- Geology Department, Université de Liège, B18 Allée du 6 Août, 4000, Liège, Belgium,
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Chen XH, Motani R, Cheng L, Jiang DY, Rieppel O. A carapace-like bony 'body tube' in an early triassic marine reptile and the onset of marine tetrapod predation. PLoS One 2014; 9:e94396. [PMID: 24718682 PMCID: PMC3981804 DOI: 10.1371/journal.pone.0094396] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Accepted: 03/13/2014] [Indexed: 11/25/2022] Open
Abstract
Parahupehsuchus longus is a new species of marine reptile from the Lower Triassic of Yuan’an County, Hubei Province, China. It is unique among vertebrates for having a body wall that is completely surrounded by a bony tube, about 50 cm long and 6.5 cm deep, comprising overlapping ribs and gastralia. This tube and bony ossicles on the back are best interpreted as anti-predatory features, suggesting that there was predation pressure upon marine tetrapods in the Early Triassic. There is at least one sauropterygian that is sufficiently large to feed on Parahupehsuchus in the Nanzhang-Yuan’an fauna, together with six more species of potential prey marine reptiles with various degrees of body protection. Modern predators of marine tetrapods belong to the highest trophic levels in the marine ecosystem but such predators did not always exist through geologic time. The indication of marine-tetrapod feeding in the Nanzhang-Yuan’an fauna suggests that such a trophic level emerged for the first time in the Early Triassic. The recovery from the end-Permian extinction probably proceeded faster than traditionally thought for marine predators. Parahupehsuchus has superficially turtle-like features, namely expanded ribs without intercostal space, very short transverse processes, and a dorsal outgrowth from the neural spine. However, these features are structurally different from their turtle counterparts. Phylogeny suggests that they are convergent with the condition in turtles, which has a fundamentally different body plan that involves the folding of the body wall. Expanded ribs without intercostal space evolved at least twice and probably even more among reptiles.
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Affiliation(s)
- Xiao-hong Chen
- Wuhan Center of China Geological Survey, Wuhan, Hubei, P. R. China
| | - Ryosuke Motani
- Department of Earth and Planetary Sciences, University of California Davis, Davis, California, United States of America
| | - Long Cheng
- Wuhan Center of China Geological Survey, Wuhan, Hubei, P. R. China
| | - Da-yong Jiang
- Laboratory of Orogenic Belt and Crustal Evolution, Ministry of Education, Department of Geology and Geological Museum, Peking University, Beijing, P.R. China
| | - Olivier Rieppel
- Center of Integrative Research, The Field Museum, Chicago, Illinois, United States of America
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Scheyer TM, Romano C, Jenks J, Bucher H. Early Triassic marine biotic recovery: the predators' perspective. PLoS One 2014; 9:e88987. [PMID: 24647136 PMCID: PMC3960099 DOI: 10.1371/journal.pone.0088987] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Accepted: 01/13/2014] [Indexed: 11/18/2022] Open
Abstract
Examining the geological past of our planet allows us to study periods of severe climatic and biological crises and recoveries, biotic and abiotic ecosystem fluctuations, and faunal and floral turnovers through time. Furthermore, the recovery dynamics of large predators provide a key for evaluation of the pattern and tempo of ecosystem recovery because predators are interpreted to react most sensitively to environmental turbulences. The end-Permian mass extinction was the most severe crisis experienced by life on Earth, and the common paradigm persists that the biotic recovery from the extinction event was unusually slow and occurred in a step-wise manner, lasting up to eight to nine million years well into the early Middle Triassic (Anisian) in the oceans, and even longer in the terrestrial realm. Here we survey the global distribution and size spectra of Early Triassic and Anisian marine predatory vertebrates (fishes, amphibians and reptiles) to elucidate the height of trophic pyramids in the aftermath of the end-Permian event. The survey of body size was done by compiling maximum standard lengths for the bony fishes and some cartilaginous fishes, and total size (estimates) for the tetrapods. The distribution and size spectra of the latter are difficult to assess because of preservation artifacts and are thus mostly discussed qualitatively. The data nevertheless demonstrate that no significant size increase of predators is observable from the Early Triassic to the Anisian, as would be expected from the prolonged and stepwise trophic recovery model. The data further indicate that marine ecosystems characterized by multiple trophic levels existed from the earliest Early Triassic onwards. However, a major change in the taxonomic composition of predatory guilds occurred less than two million years after the end-Permian extinction event, in which a transition from fish/amphibian to fish/reptile-dominated higher trophic levels within ecosystems became apparent.
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Affiliation(s)
- Torsten M. Scheyer
- Paläontologisches Institut und Museum, Universität Zürich, Zürich, Switzerland
- * E-mail: (TMS); (CR)
| | - Carlo Romano
- Paläontologisches Institut und Museum, Universität Zürich, Zürich, Switzerland
- * E-mail: (TMS); (CR)
| | - Jim Jenks
- West Jordan, Utah, United States of America
- New Mexico Museum of Natural History and Science, Albuquerque, New Mexico, United States of America
| | - Hugo Bucher
- Paläontologisches Institut und Museum, Universität Zürich, Zürich, Switzerland
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