The oldest gnathostome teeth

Andreev, Plamen S.; Sansom, Ivan J.; Li, Qiang; Zhao, Wenjin; Wang, Jianhua; Wang, Chun‐Chieh; Peng, Lijian; Jia, Liantao; Qiao, Tuo; Zhu, Min

doi:10.1038/s41586-022-05166-2

Cited by 22 publications

(5 citation statements)

References 49 publications

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“…[10,26–30]). These hypotheses of range extension have now been confirmed with body fossils and further diagnostic fragments from the Early Silurian of China [3,31,32]. However, how the quality of these various fossils and their differing degrees of completeness influence estimated patterns of diversity and phylogenetic relationship remains uncertain.…”

Section: Introductionmentioning

confidence: 98%

The skeletal completeness of the Palaeozoic chondrichthyan fossil record

Schnetz,

Butler,

Coates

et al. 2024

R. Soc. Open Sci.

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Chondrichthyes (sharks, rays, ratfish and their extinct relatives) originated and diversified in the Palaeozoic but are rarely preserved as articulated or partly articulated remains because of their predominantly cartilaginous endoskeletons. Consequently, their evolutionary history is perceived to be documented predominantly by isolated teeth, scales and fin spines. Here, we aim to capture and analyse the quality of the Palaeozoic chondrichthyan fossil record by using a variation of the skeletal completeness metric, which calculates how complete the skeletons of individuals are compared to estimates of their original entirety. Notably, chondrichthyan completeness is significantly lower than any published vertebrate group: low throughout the Silurian and Permian but peaking in the Devonian and Carboniferous. Scores increase to a range similar to pelycosaurs and parareptiles only when taxa identified solely from isolated teeth, scales and spines are excluded. We argue that environmental influences probably played an important role in chondrichthyan completeness. Sea level significantly negatively correlates with chondrichthyan completeness records and resembles patterns already evident in records of ichthyosaurs, plesiosaurs and sauropodomorphs. Such observed variations in completeness highlight the impact of different sampling biases on the chondrichthyan fossil record and the need to acknowledge these when inferring patterns of chondrichthyan macroevolution.

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Section: Introductionmentioning

confidence: 98%

The skeletal completeness of the Palaeozoic chondrichthyan fossil record

Schnetz,

Butler,

Coates

et al. 2024

R. Soc. Open Sci.

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“…The early fossil record of chondrichthyans (cartilaginous fishes, including sharks, rays, skates and chimaeras) likely dates back to the Late Ordovician (Young 1997; Sansom et al 2001, 2012; Andreev et al 2015, 2016; Sansom and Andreev 2017). However, undoubted chondrichthyans first appeared in the early Silurian (Andreev et al 2022a,b; Zhu et al 2022) and rapidly diversified during the Devonian and early Carboniferous (Coates et al 2018), alongside other major jawed vertebrate groups such as actinopterygians, sarcopterygians, and placoderms (Janvier 1996; Sepkoski 2002; Turner 2004; Brazeau 2009; Ginter et al 2010; Sallan and Coates 2010). The recognition of the acanthodians, a group of Paleozoic spiny fusiform fishes, as a grade within the chondrichthyan stem-group has added considerable data to the earliest chondrichthyan fossil record (e.g., Brazeau 2009; Davis et al 2012; Coates et al 2018; Dearden et al 2019; Burrow 2021) and identified a crucial step in early chondrichthyan evolution.…”

Section: Introductionmentioning

confidence: 99%

Rise and diversification of chondrichthyans in the Paleozoic

Schnetz,

Dunne,

Feichtinger

et al. 2024

Paleobiology

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The Paleozoic represents a key time interval in the origins and early diversification of chondrichthyans (cartilaginous fishes), but their diversity and macroevolution are largely obscured by heterogenous spatial and temporal sampling. The predominantly cartilaginous skeletons of chondrichthyans pose an additional limitation on their preservation potential and hence on the quality of their fossil record. Here, we use a newly compiled genus-level dataset and the application of sampling standardization methods to analyze global total-chondrichthyan diversity dynamics through time from their first appearance in the Ordovician through to the end of the Permian. Subsampled estimates of chondrichthyan genus richness were initially low in the Ordovician and Silurian but increased substantially in the Early Devonian. Richness reached its maximum in the middle Carboniferous before dropping across the Carboniferous/Permian boundary and gradually decreasing throughout the Permian. Sampling is higher in both the Devonian and Carboniferous compared with the Silurian and most of the Permian stages. Shark-like scales from the Ordovician are too limited to allow for some of the subsampling techniques. Our results detect two Paleozoic radiations in chondrichthyan diversity: the first in the earliest Devonian, led by acanthodians (stem-group chondrichthyans), which then decline rapidly by the Late Devonian, and the second in the earliest Carboniferous, led by holocephalans, which increase greatly in richness across the Devonian/Carboniferous boundary. Dispersal of chondrichthyans, specifically holocephalans, into deeper-water environments may reflect a niche expansion following the faunal displacement in the aftermath of the Hangenberg extinction event at the end of the Devonian.

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“…Recently, Chinese scientists confirmed that humans evolved from fish. The journal Nature reports on the origin and earliest evolution of jawed vertebrates, which provide key evidence for the transition from fish to man [8][9][10][11]. This suggests that fish would have great credibility as a model animal for research.…”

Section: Introductionmentioning

confidence: 99%

Advances in Zebrafish as a Comprehensive Model of Mental Disorders

Wang

Liu

Fang

et al. 2023

Depression and Anxiety

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As an important part in international disease, mental disorders seriously damage human health and social stability, which show the complex pathogenesis and increasing incidence year by year. In order to analyze the pathogenesis of mental disorders as soon as possible and to look for the targeted drug treatment for psychiatric diseases, a more reasonable animal model is imperious demands. Benefiting from its high homology with the human genome, its brain tissue is highly similar to that of humans, and it is easy to realize whole-body optical visualization and high-throughput screening; zebrafish stands out among many animal models of mental disorders. Here, valuable qualified zebrafish mental disorders models could be established through behavioral test and sociological analysis, which are simulated to humans, and combined with molecular analyses and other detection methods. This review focuses on the advances in the zebrafish model to simulate the human mental disorders; summarizes the various behavioral characterization means, the use of equipment, and operation principle; sums up the various mental disorder zebrafish model modeling methods; puts forward the current challenges and future development trend, which is to contribute the theoretical supports for the exploration of the mechanisms and treatment strategies of mental disorders.

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The oldest gnathostome teeth

Cited by 22 publications

References 49 publications

The skeletal completeness of the Palaeozoic chondrichthyan fossil record

The skeletal completeness of the Palaeozoic chondrichthyan fossil record

Rise and diversification of chondrichthyans in the Paleozoic

Advances in Zebrafish as a Comprehensive Model of Mental Disorders

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