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Brownstein CD, Near T. Colonization of the ocean floor by jawless vertebrates across three mass extinctions. BMC Ecol Evol 2024; 24:79. [PMID: 38867201 PMCID: PMC11170801 DOI: 10.1186/s12862-024-02253-y] [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: 01/16/2024] [Accepted: 05/07/2024] [Indexed: 06/14/2024] Open
Abstract
BACKGROUND The deep (> 200 m) ocean floor is often considered to be a refugium of biodiversity; many benthic marine animals appear to share ancient common ancestry with nearshore and terrestrial relatives. Whether this pattern holds for vertebrates is obscured by a poor understanding of the evolutionary history of the oldest marine vertebrate clades. Hagfishes are jawless vertebrates that are either the living sister to all vertebrates or form a clade with lampreys, the only other surviving jawless fishes. RESULTS We use the hagfish fossil record and molecular data for all recognized genera to construct a novel hypothesis for hagfish relationships and diversification. We find that crown hagfishes persisted through three mass extinctions after appearing in the Permian ~ 275 Ma, making them one of the oldest living vertebrate lineages. In contrast to most other deep marine vertebrates, we consistently infer a deep origin of continental slope occupation by hagfishes that dates to the Paleozoic. Yet, we show that hagfishes have experienced marked body size diversification over the last hundred million years, contrasting with a view of this clade as morphologically stagnant. CONCLUSION Our results establish hagfishes as ancient members of demersal continental slope faunas and suggest a prolonged accumulation of deep sea jawless vertebrate biodiversity.
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Affiliation(s)
- Chase Doran Brownstein
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, 06511, USA.
| | - Thomas Near
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, 06511, USA
- Yale Peabody Museum, Yale University, New Haven, CT, 06511, USA
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2
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Liu X, Song H, Chu D, Dai X, Wang F, Silvestro D. Heterogeneous selectivity and morphological evolution of marine clades during the Permian-Triassic mass extinction. Nat Ecol Evol 2024:10.1038/s41559-024-02438-0. [PMID: 38862784 DOI: 10.1038/s41559-024-02438-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2024] [Accepted: 05/10/2024] [Indexed: 06/13/2024]
Abstract
Morphological disparity and taxonomic diversity are distinct measures of biodiversity, typically expected to evolve synergistically. However, evidence from mass extinctions indicates that they can be decoupled, and while mass extinctions lead to a drastic loss of diversity, their impact on disparity remains unclear. Here we evaluate the dynamics of morphological disparity and extinction selectivity across the Permian-Triassic mass extinction. We developed an automated approach, termed DeepMorph, for the extraction of morphological features from fossil images using a deep learning model and applied it to a high-resolution temporal dataset encompassing 599 genera across six marine clades. Ammonoids, brachiopods and ostracods experienced a selective loss of complex and ornamented forms, while bivalves, gastropods and conodonts did not experience morphologically selective extinctions. The presence and intensity of morphological selectivity probably reflect the variations in environmental tolerance thresholds among different clades. In clades affected by selective extinctions, the intensity of diversity loss promoted the loss of morphological disparity. Conversely, under non-selective extinctions, the magnitude of diversity loss had a negligible impact on disparity. Our results highlight that the Permian-Triassic mass extinction had heterogeneous morphological selective impacts across clades, offering new insights into how mass extinctions can reshape biodiversity and ecosystem structure.
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Affiliation(s)
- Xiaokang Liu
- State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, Wuhan, China
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Haijun Song
- State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, Wuhan, China.
| | - Daoliang Chu
- State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, Wuhan, China
| | - Xu Dai
- State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, Wuhan, China
| | - Fengyu Wang
- State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, Wuhan, China
| | - Daniele Silvestro
- Department of Biology, University of Fribourg, Fribourg, Switzerland
- Swiss Institute of Bioinformatics, Fribourg, Switzerland
- Gothenburg Global Biodiversity Centre, Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
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3
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Sun J, Liu X, Huang Y, Wang F, Sun Y, Chen J, Chu D, Song H. Automatic identification and morphological comparison of bivalve and brachiopod fossils based on deep learning. PeerJ 2023; 11:e16200. [PMID: 37842038 PMCID: PMC10576495 DOI: 10.7717/peerj.16200] [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: 03/06/2023] [Accepted: 09/07/2023] [Indexed: 10/17/2023] Open
Abstract
Fossil identification is an essential and fundamental task for conducting palaeontological research. Because the manual identification of fossils requires extensive experience and is time-consuming, automatic identification methods are proposed. However, these studies are limited to a few or dozens of species, which is hardly adequate for the needs of research. This study enabled the automatic identification of hundreds of species based on a newly established fossil dataset. An available "bivalve and brachiopod fossil image dataset" (BBFID, containing >16,000 "image-label" data pairs, taxonomic determination completed) was created. The bivalves and brachiopods contained in BBFID are closely related in morphology, ecology and evolution that have long attracted the interest of researchers. We achieved >80% identification accuracy at 22 genera and ∼64% accuracy at 343 species using EfficientNetV2s architecture. The intermediate output of the model was extracted and downscaled to obtain the morphological feature space of fossils using t-distributed stochastic neighbor embedding (t-SNE). We found a distinctive boundary between the morphological feature points of bivalves and brachiopods in fossil morphological feature distribution maps. This study provides a possible method for studying the morphological evolution of fossil clades using computer vision in the future.
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Affiliation(s)
- Jiarui Sun
- State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, Wuhan, Hubei, China
| | - Xiaokang Liu
- State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, Wuhan, Hubei, China
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Yunfei Huang
- School of Geosciences, Yangtze University, Wuhan, Hubei, China
| | - Fengyu Wang
- State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, Wuhan, Hubei, China
| | - Yongfang Sun
- State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, Wuhan, Hubei, China
| | - Jing Chen
- Yifu Museum, China University of Geosciences, Wuhan, Hubei, China
| | - Daoliang Chu
- State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, Wuhan, Hubei, China
| | - Haijun Song
- State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, Wuhan, Hubei, China
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4
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Guinot G, Condamine FL. Global impact and selectivity of the Cretaceous-Paleogene mass extinction among sharks, skates, and rays. Science 2023; 379:802-806. [PMID: 36821692 DOI: 10.1126/science.abn2080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
The Cretaceous-Paleogene event was the last mass extinction event, yet its impact and long-term effects on species-level marine vertebrate diversity remain largely uncharacterized. We quantified elasmobranch (sharks, skates, and rays) speciation, extinction, and ecological change resulting from the end-Cretaceous event using >3200 fossil occurrences and 675 species spanning the Late Cretaceous-Paleocene interval at global scale. Elasmobranchs declined by >62% at the Cretaceous-Paleogene boundary and did not fully recover in the Paleocene. The end-Cretaceous event triggered a heterogeneous pattern of extinction, with rays and durophagous species reaching the highest levels of extinction (>72%) and sharks and nondurophagous species being less affected. Taxa with large geographic ranges and/or those restricted to high-latitude settings show higher survival. The Cretaceous-Paleogene event drastically altered the evolutionary history of marine ecosystems.
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Affiliation(s)
- Guillaume Guinot
- Institut des Sciences de l'Évolution de Montpellier, Université de Montpellier, CNRS, IRD, EPHE, Place Eugène Bataillon, 34095 Montpellier, France
| | - Fabien L Condamine
- Institut des Sciences de l'Évolution de Montpellier, Université de Montpellier, CNRS, IRD, EPHE, Place Eugène Bataillon, 34095 Montpellier, France
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5
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Hoffman DK, Hancox JP, Nesbitt SJ. A diverse diapsid tooth assemblage from the Early Triassic (Driefontein locality, South Africa) records the recovery of diapsids following the end-Permian mass extinction. PLoS One 2023; 18:e0285111. [PMID: 37126508 PMCID: PMC10150976 DOI: 10.1371/journal.pone.0285111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 04/15/2023] [Indexed: 05/02/2023] Open
Abstract
Mass extinctions change the trajectory of evolution and restructure ecosystems. The largest mass extinction, the end-Permian, is a particularly interesting case due to the hypothesized delay in the recovery of global ecosystems, where total trophic level recovery is not thought to have occurred until 5-9 million years after the extinction event. Diapsids, especially archosauromorphs, play an important role in this recovery, filling niches left vacant by therapsids and anapsids. However, the nature of lineage and ecological diversification of diapsids is obscured by the limited number of continuous, well-dated stratigraphic sections at the Permian-Triassic boundary and continuing through the first half of the Triassic. The Karoo Basin of South Africa is one such record, and particularly the late Early Triassic (Olenekian) Driefontein locality fills this gap in the diapsid fossil record. We collected a total of 102 teeth of which 81 are identified as diapsids and the remaining 21 as identified as temnospondyls. From the sample, seven distinct tooth morphotypes of diapsids are recognized, six of which are new to the locality. We used a combination of linear measurements, 3D geomorphometrics, and nMDS ordination to compare these morphotypes and made inferences about their possible diets. Although the morphotypes are readily differentiated in nMDS, the overall morphological disparity is low, and we infer five morphotypes are faunivorous with the other two potentially omnivorous or piscivorous based on their morphological similarities with dentitions from extant diapsids, demonstrating an unsampled taxonomic and ecological diversity of diapsids in the Early Triassic based on teeth. Although ecological specialization at Driefontein may be low, it records a diversity of diapsid taxa, specifically of archosauromorph lineages.
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Affiliation(s)
- Devin K Hoffman
- Department of Geosciences, Virginia Tech, Blacksburg, VA, United States of America
| | - John P Hancox
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
| | - Sterling J Nesbitt
- Department of Geosciences, Virginia Tech, Blacksburg, VA, United States of America
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6
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Türtscher J, López-Romero FA, Jambura PL, Kindlimann R, Ward DJ, Kriwet J. Evolution, diversity, and disparity of the tiger shark lineage Galeocerdo in deep time. PALEOBIOLOGY 2021; 47:574-590. [PMID: 34866693 PMCID: PMC7612061 DOI: 10.1017/pab.2021.6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Sharks have a long and rich fossil record that consists predominantly of isolated teeth due to the poorly mineralized cartilaginous skeleton. Tiger sharks (Galeocerdo), which represent apex predators in modern oceans, have a known fossil record extending back into the early Eocene (ca. 56 Ma) and comprise 22 recognized extinct and one extant species to date. However, many of the fossil species remain dubious, resulting in a still unresolved evolutionary history of the tiger shark genus. Here, we present a revision of the fossil record of Galeocerdo by examining the morphological diversity and disparity of teeth in deep time. We use landmark-based geometric morphometrics to quantify tooth shapes and qualitative morphological characters for species discrimination. Employing this combined approach on fossil and extant tiger shark teeth, our results only support six species to represent valid taxa. Furthermore, the disparity analysis revealed that diversity and disparity are not implicitly correlated and that Galeocerdo retained a relatively high dental disparity since the Miocene despite its decrease from four to one species. With this study, we demonstrate that the combined approach of quantitative geometric morphometric techniques and qualitative morphological comparisons on isolated shark teeth provides a useful tool to distinguish between species with highly similar tooth morphologies.
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Affiliation(s)
| | - Faviel A. López-Romero
- Department of Palaeontology, University of Vienna, Althanstraβe 14, 1090 Vienna, Austria
| | - Patrick L. Jambura
- Department of Palaeontology, University of Vienna, Althanstraβe 14, 1090 Vienna, Austria
| | - René Kindlimann
- Haimuseum und Sammlung R. Kindlimann, Aathal-Seegräben, Switzerland
| | - David J. Ward
- Department of Earth Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, U.K
| | - Jürgen Kriwet
- Department of Palaeontology, University of Vienna, Althanstraβe 14, 1090 Vienna, Austria
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7
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Feeding ecology has shaped the evolution of modern sharks. Curr Biol 2021; 31:5138-5148.e4. [PMID: 34614390 DOI: 10.1016/j.cub.2021.09.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 06/05/2021] [Accepted: 09/09/2021] [Indexed: 11/20/2022]
Abstract
Sharks are iconic predators in today's oceans, yet their modern diversity has ancient origins. In particular, present hypotheses suggest that a combination of mass extinction, global climate change, and competition has regulated the community structure of dominant mackerel (Lamniformes) and ground (Carcharhiniformes) sharks over the last 66 million years. However, while these scenarios advocate an interplay of major abiotic and biotic events, the precise drivers remain obscure. Here, we focus on the role of feeding ecology using a geometric morphometric analysis of 3,837 fossil and extant shark teeth. Our results reveal that morphological segregation rather than competition has characterized lamniform and carcharhiniform evolution. Moreover, although lamniforms suffered a long-term disparity decline potentially linked to dietary "specialization," their recent disparity rivals that of "generalist" carcharhiniforms. We further confirm that low eustatic sea levels impacted lamniform disparity across the end-Cretaceous mass extinction. Adaptations to changing prey availability and the proliferation of coral reef habitats during the Paleogene also likely facilitated carcharhiniform dispersals and cladogenesis, underpinning their current taxonomic dominance. Ultimately, we posit that trophic partitioning and resource utilization shaped past shark ecology and represent critical determinants for their future species survivorship.
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8
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Bazzi M, Campione NE, Ahlberg PE, Blom H, Kear BP. Tooth morphology elucidates shark evolution across the end-Cretaceous mass extinction. PLoS Biol 2021; 19:e3001108. [PMID: 34375335 PMCID: PMC8354442 DOI: 10.1371/journal.pbio.3001108] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 07/05/2021] [Indexed: 02/05/2023] Open
Abstract
Sharks (Selachimorpha) are iconic marine predators that have survived multiple mass extinctions over geologic time. Their prolific fossil record is represented mainly by isolated shed teeth, which provide the basis for reconstructing deep time diversity changes affecting different selachimorph clades. By contrast, corresponding shifts in shark ecology, as measured through morphological disparity, have received comparatively limited analytical attention. Here, we use a geometric morphometric approach to comprehensively examine tooth morphologies in multiple shark lineages traversing the catastrophic end-Cretaceous mass extinction-this event terminated the Mesozoic Era 66 million years ago. Our results show that selachimorphs maintained virtually static levels of dental disparity in most of their constituent clades across the Cretaceous-Paleogene interval. Nevertheless, selective extinctions did impact apex predator species characterized by triangular blade-like teeth. This is particularly evident among lamniforms, which included the dominant Cretaceous anacoracids. Conversely, other groups, such as carcharhiniforms and orectolobiforms, experienced disparity modifications, while heterodontiforms, hexanchiforms, squaliforms, squatiniforms, and †synechodontiforms were not overtly affected. Finally, while some lamniform lineages disappeared, others underwent postextinction disparity increases, especially odontaspidids, which are typified by narrow-cusped teeth adapted for feeding on fishes. Notably, this increase coincides with the early Paleogene radiation of teleosts as a possible prey source, and the geographic relocation of disparity sampling "hotspots," perhaps indicating a regionally disjunct extinction recovery. Ultimately, our study reveals a complex morphological response to the end-Cretaceous mass extinction and highlights an event that influenced the evolution of modern sharks.
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Affiliation(s)
- Mohamad Bazzi
- Subdepartment of Evolution and Development, Department of Organismal Biology, Uppsala University, Uppsala, Sweden
| | - Nicolás E. Campione
- Palaeoscience Research Centre, School of Environmental and Rural Science, University of New England, Armidale, New South Wales, Australia
| | - Per E. Ahlberg
- Subdepartment of Evolution and Development, Department of Organismal Biology, Uppsala University, Uppsala, Sweden
| | - Henning Blom
- Subdepartment of Evolution and Development, Department of Organismal Biology, Uppsala University, Uppsala, Sweden
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9
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White MA, Campione NE. A three-dimensional approach to visualize pairwise morphological variation and its application to fragmentary palaeontological specimens. PeerJ 2021; 9:e10545. [PMID: 33552712 PMCID: PMC7821773 DOI: 10.7717/peerj.10545] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 11/20/2020] [Indexed: 12/30/2022] Open
Abstract
Classifying isolated vertebrate bones to a high level of taxonomic precision can be difficult. Many of Australia's Cretaceous terrestrial vertebrate fossil-bearing deposits, for example, produce large numbers of isolated bones and very few associated or articulated skeletons. Identifying these often fragmentary remains beyond high-level taxonomic ranks, such as Ornithopoda or Theropoda, is difficult and those classified to lower taxonomic levels are often debated. The ever-increasing accessibility to 3D-based comparative techniques has allowed palaeontologists to undertake a variety of shape analyses, such as geometric morphometrics, that although powerful and often ideal, require the recognition of diagnostic landmarks and the generation of sufficiently large data sets to detect clusters and accurately describe major components of morphological variation. As a result, such approaches are often outside the scope of basic palaeontological research that aims to simply identify fragmentary specimens. Herein we present a workflow in which pairwise comparisons between fragmentary fossils and better known exemplars are digitally achieved through three-dimensional mapping of their surface profiles and the iterative closest point (ICP) algorithm. To showcase this methodology, we compared a fragmentary theropod ungual (NMV P186153) from Victoria, Australia, identified as a neovenatorid, with the manual unguals of the megaraptoran Australovenator wintonensis (AODF604). We discovered that NMV P186153 was a near identical match to AODF604 manual ungual II-3, differing only in size, which, given their 10-15Ma age difference, suggests stasis in megaraptoran ungual morphology throughout this interval. Although useful, our approach is not free of subjectivity; care must be taken to eliminate the effects of broken and incomplete surfaces and identify the human errors incurred during scaling, such as through replication. Nevertheless, this approach will help to evaluate and identify fragmentary remains, adding a quantitative perspective to an otherwise qualitative endeavour.
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Affiliation(s)
- Matt A. White
- Palaeoscience Research Centre, School of Environment and Rural Science, University of New England, Armidale, NSW, Australia
- Palaeontology, Australian Age of Dinosaurs Museum of Natural History, Winton, QLD, Australia
| | - Nicolás E. Campione
- Palaeoscience Research Centre, School of Environment and Rural Science, University of New England, Armidale, NSW, Australia
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10
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Berio F, Evin A, Goudemand N, Debiais‐Thibaud M. The intraspecific diversity of tooth morphology in the large-spotted catshark Scyliorhinus stellaris: insights into the ontogenetic cues driving sexual dimorphism. J Anat 2020; 237:960-978. [PMID: 32667054 PMCID: PMC7542197 DOI: 10.1111/joa.13257] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Revised: 05/02/2020] [Accepted: 05/26/2020] [Indexed: 02/06/2023] Open
Abstract
Teeth in sharks are shed and replaced throughout their lifetime. Morphological dental changes through ontogeny have been identified in several species and have been correlated with shifts in diet and the acquisition of sexual maturity. However, these changes were rarely quantified in detail along multiple ontogenetic stages, which makes it difficult to infer the developmental processes responsible for the observed plasticity. In this work, we use micro-computed tomography and 3D geometric morphometrics to describe and analyze the tooth size and shape diversity across three ontogenetic stages (hatchling, juvenile, and sexually mature) in the large-spotted catshark Scyliorhinus stellaris (Linnaeus, 1758). We first describe the intra-individual variation of tooth form for each sex at each ontogenetic stage. We provide a tooth morphospace for palatoquadrate and Meckelian teeth and identify dental features, such as relative size and number of cusps, involved in the range of variation of the observed morphologies. We then use these shape data to draw developmental trajectories between ontogenetic stages and for each tooth position within the jaw to characterize ontogenetic patterns of sexual dimorphism. We highlight the emergence of gynandric heterodonty between the juvenile and mature ontogenetic stages, with mature females having tooth morphologies more similar to juveniles' than mature males that display regression in the number of accessory cusps. From these data, we speculate on the developmental processes that could account for such developmental plasticity in S. stellaris.
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Affiliation(s)
- Fidji Berio
- CNRS, IRD, EPHEUMR5554Institut des Sciences de l’Évolution de Montpellier, ISEMUniversité de MontpellierMontpellierFrance
- Centre National de la Recherche ScientifiqueÉcole Normale Supérieure de LyonInstitut de Génomique Fonctionnelle de LyonUMR 5242Université Claude Bernard Lyon 1Univ. LyonLyonFrance
| | - Allowen Evin
- CNRS, IRD, EPHEUMR5554Institut des Sciences de l’Évolution de Montpellier, ISEMUniversité de MontpellierMontpellierFrance
| | - Nicolas Goudemand
- Centre National de la Recherche ScientifiqueÉcole Normale Supérieure de LyonInstitut de Génomique Fonctionnelle de LyonUMR 5242Université Claude Bernard Lyon 1Univ. LyonLyonFrance
| | - Mélanie Debiais‐Thibaud
- CNRS, IRD, EPHEUMR5554Institut des Sciences de l’Évolution de Montpellier, ISEMUniversité de MontpellierMontpellierFrance
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11
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Puttick MN, Guillerme T, Wills MA. The complex effects of mass extinctions on morphological disparity. Evolution 2020; 74:2207-2220. [PMID: 32776526 DOI: 10.1111/evo.14078] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 07/23/2020] [Accepted: 07/31/2020] [Indexed: 01/01/2023]
Abstract
Studies of biodiversity through deep time have been a staple for biologists and paleontologists for over 60 years. Investigations of species richness (diversity) revealed that at least five mass extinctions punctuated the last half billion years, each seeing the rapid demise of a large proportion of contemporary taxa. In contrast to diversity, the response of morphological diversity (disparity) to mass extinctions is unclear. Generally, diversity and disparity are decoupled, such that diversity may decline as morphological disparity increases, and vice versa. Here, we develop simulations to model disparity changes across mass extinctions using continuous traits and birth-death trees. We find no simple null for disparity change following a mass extinction but do observe general patterns. The range of trait values decreases following either random or trait-selective mass extinctions, whereas variance and the density of morphospace occupation only decline following trait-selective events. General trends may differentiate random and trait-selective mass extinctions, but methods struggle to identify trait selectivity. Long-term effects of mass extinction trait selectivity change support for phylogenetic comparative methods away from the simulated Brownian motion toward Ornstein-Uhlenbeck and Early Burst models. We find that morphological change over mass extinction is best studied by quantifying multiple aspects of morphospace occupation.
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Affiliation(s)
- Mark N Puttick
- Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, Bath, BA2 7AY, United Kingdom
| | - Thomas Guillerme
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, United Kingdom
| | - Matthew A Wills
- Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, Bath, BA2 7AY, United Kingdom
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12
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Two-step extinction of Late Cretaceous marine vertebrates in northern Gulf of Mexico prolonged biodiversity loss prior to the Chicxulub impact. Sci Rep 2020; 10:4169. [PMID: 32144332 PMCID: PMC7060338 DOI: 10.1038/s41598-020-61089-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 02/14/2020] [Indexed: 12/02/2022] Open
Abstract
Recent studies on mass extinctions are often based on the global fossil record, but data from selected paleogeographic regions under a relatively constant paleoenvironmental setting can also provide important information. Eighty-nine marine vertebrate species, including cartilaginous and bony fish and marine reptiles, from northern Gulf of Mexico – located about 500 km from the Chicxulub crater – offer a unique opportunity to determine an extinction process during the last 20 million years of the Late Cretaceous. Our diversity data show two separate extinction events: (i) the ‘Middle Campanian Crisis’ (about 77 Mya) and (ii) the end-Maastrichtian (66 Mya) events. Whether this stepwise pattern of extinctions occurred locally or globally cannot be determined at present due to the lack of a dataset of the marine vertebrate record for reliable comparison. However, this stepwise pattern including the Middle Campanian and end-Maastrichtian events for, at least, a 13 million-year interval indicates long-term global marine environmental changes (e.g., regression, ocean water chemistry change). Because most Cretaceous marine vertebrates already disappeared in the Gulf of Mexico prior to the latest Maastrichtian, the Chicxulub Impact may not be considered as the most devastating extinction event for the community.
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13
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MacDougall MJ, Brocklehurst N, Fröbisch J. Species richness and disparity of parareptiles across the end-Permian mass extinction. Proc Biol Sci 2020; 286:20182572. [PMID: 30890099 DOI: 10.1098/rspb.2018.2572] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The amniote clade Parareptilia is notable in that members of the clade exhibited a wide array of morphologies, were successful in a variety of ecological niches and survived the end-Permian mass extinction. In order to better understand how mass extinction events can affect clades that survive them, we investigate both the species richness and morphological diversity (disparity) of parareptiles over the course of their history. Furthermore, we examine our observations in the context of other metazoan clades, in order to identify post-extinction survivorship patterns that are present in the clade. The results of our study indicate that there was an early increase in parareptilian disparity, which then fluctuated over the course of the Permian, before it eventually declined sharply towards the end of the Permian and into the Triassic, corresponding with the end-Permian mass extinction event. Interestingly, this is a different trend to what is observed regarding parareptile richness, that shows an almost continuous increase until its overall peak at the end of the Late Permian. Moreover, richness did not experience the same sharp drop at the end of the Permian, reaching a plateau until the Anisian, before dropping sharply and remaining low, with the clade going extinct at the end of the Triassic. This observed pattern is likely to be due to the fact that, despite the extinction of several morphologically distinct parareptile clades, the procolophonoids, one of the largest parareptilian clades, were diversifying across the Permian-Triassic boundary. With the clade's low levels of disparity and eventually declining species richness, this pattern most resembles a 'dead clade walking' pattern.
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Affiliation(s)
- Mark J MacDougall
- 1 Museum für Naturkunde, Leibniz-Institut für Evolutions-und Biodiversitätsforschung , Berlin , Germany
| | - Neil Brocklehurst
- 1 Museum für Naturkunde, Leibniz-Institut für Evolutions-und Biodiversitätsforschung , Berlin , Germany.,2 Department of Earth Sciences, University of Oxford , Oxford , UK
| | - Jörg Fröbisch
- 1 Museum für Naturkunde, Leibniz-Institut für Evolutions-und Biodiversitätsforschung , Berlin , Germany.,3 Humboldt-Universität zu Berlin , Berlin , Germany
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Climate cooling and clade competition likely drove the decline of lamniform sharks. Proc Natl Acad Sci U S A 2019; 116:20584-20590. [PMID: 31548392 DOI: 10.1073/pnas.1902693116] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Understanding heterogeneity in species richness between closely related clades is a key research question in ecology and evolutionary biology. Multiple hypotheses have been proposed to interpret such diversity contrasts across the tree of life, with most studies focusing on speciation rates to explain clades' evolutionary radiations, while often neglecting extinction rates. Here we study a notorious biological model as exemplified by the sister relationships between mackerel sharks (Lamniformes, 15 extant species) and ground sharks (Carcharhiniformes, ∼290 extant species). Using a comprehensive fossil dataset, we found that the diversity dynamics of lamniforms waxed and waned following repeated cycles of radiation phases and declining phases. Radiation phases peaked up to 3 times the current diversity in the early Late Cretaceous. In the last 20 million years, the group declined to its present-day diversity. Along with a higher extinction risk for young species, we further show that this declining pattern is likely attributed to a combination of abiotic and biotic factors, with a cooling-driven extinction (negative correlation between temperature and extinction) and clade competition with some ground sharks. Competition from multiple clades successively drove the demise and replacement of mackerel sharks due to a failure to originate facing the rise of ground sharks, particularly since the Eocene. These effects came from ecologically similar carcharhiniform species inhibiting diversification of medium- and large-sized lamniforms. These results imply that the interplay between abiotic and biotic drivers had a substantial role in extinction and speciation, respectively, which determines the sequential rise and decline of marine apex predators.
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