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Figueroa RT, Andrews JV. Fitting fangs in a finite face: A novel fang accommodation strategy in a 280-million-year-old ray-finned fish. J Anat 2022; 242:525-534. [PMID: 36434746 PMCID: PMC9919467 DOI: 10.1111/joa.13798] [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: 08/28/2022] [Revised: 10/25/2022] [Accepted: 11/11/2022] [Indexed: 11/27/2022] Open
Abstract
Though Paleozoic ray-finned fishes are considered to be morphologically conservative, we report a novel mode of fang accommodation (i.e., the fitting of fangs inside the jaw) in the Permian actinopterygian †Brazilichthys macrognathus, whereby the teeth of the lower jaw insert into fenestrae of the upper jaw. To better understand how fishes have accommodated lower jaw fangs through geologic time, we synthesize the multitude of ways living and extinct osteichthyans have housed large mandibular dentition. While the precise structure of fang accommodation seen in †Brazilichthys has not been reported in any other osteichthyans, alternate strategies of upper jaw fenestration to fit mandibular fangs are present in some extant ray-finned fishes-the needlejaws Acestrorhynchus and the gars of the genus Lepisosteus. Notably, out of our survey, only the two aforementioned neopterygians bear upper jaw fenestration for the accommodation of mandibular fangs. We implicate the kinetic jaws of neopterygians in this trend, whereby large mandibular fangs are more easily fit between the multitude of upper jaw and palatal bones. The restricted space available in early osteichthyan jaws may have led to a proliferation of novel ways to accommodate large dentition. We recommend a greater survey of Paleozoic actinopterygian jaw morphology, in light of these results and other recent reevaluations of jaw structure in early fossil ray-fins.
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Affiliation(s)
- Rodrigo T. Figueroa
- Department of Earth and Environmental SciencesUniversity of MichiganAnn ArborMichiganUSA
| | - James V. Andrews
- Department of Earth and Environmental SciencesUniversity of MichiganAnn ArborMichiganUSA
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Romano C, Koot MB, Kogan I, Brayard A, Minikh AV, Brinkmann W, Bucher H, Kriwet J. Permian-Triassic Osteichthyes (bony fishes): diversity dynamics and body size evolution. Biol Rev Camb Philos Soc 2014; 91:106-47. [PMID: 25431138 DOI: 10.1111/brv.12161] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Revised: 10/14/2014] [Accepted: 10/22/2014] [Indexed: 12/01/2022]
Abstract
The Permian and Triassic were key time intervals in the history of life on Earth. Both periods are marked by a series of biotic crises including the most catastrophic of such events, the end-Permian mass extinction, which eventually led to a major turnover from typical Palaeozoic faunas and floras to those that are emblematic for the Mesozoic and Cenozoic. Here we review patterns in Permian-Triassic bony fishes, a group whose evolutionary dynamics are understudied. Based on data from primary literature, we analyse changes in their taxonomic diversity and body size (as a proxy for trophic position) and explore their response to Permian-Triassic events. Diversity and body size are investigated separately for different groups of Osteichthyes (Dipnoi, Actinistia, 'Palaeopterygii', 'Subholostei', Holostei, Teleosteomorpha), within the marine and freshwater realms and on a global scale (total diversity) as well as across palaeolatitudinal belts. Diversity is also measured for different palaeogeographical provinces. Our results suggest a general trend from low osteichthyan diversity in the Permian to higher levels in the Triassic. Diversity dynamics in the Permian are marked by a decline in freshwater taxa during the Cisuralian. An extinction event during the end-Guadalupian crisis is not evident from our data, but 'palaeopterygians' experienced a significant body size increase across the Guadalupian-Lopingian boundary and these fishes upheld their position as large, top predators from the Late Permian to the Late Triassic. Elevated turnover rates are documented at the Permian-Triassic boundary, and two distinct diversification events are noted in the wake of this biotic crisis, a first one during the Early Triassic (dipnoans, actinistians, 'palaeopterygians', 'subholosteans') and a second one during the Middle Triassic ('subholosteans', neopterygians). The origination of new, small taxa predominantly among these groups during the Middle Triassic event caused a significant reduction in osteichthyan body size. Neopterygii, the clade that encompasses the vast majority of extant fishes, underwent another diversification phase in the Late Triassic. The Triassic radiation of Osteichthyes, predominantly of Actinopterygii, which only occurred after severe extinctions among Chondrichthyes during the Middle-Late Permian, resulted in a profound change within global fish communities, from chondrichthyan-rich faunas of the Permo-Carboniferous to typical Mesozoic and Cenozoic associations dominated by actinopterygians. This turnover was not sudden but followed a stepwise pattern, with leaps during extinction events.
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Affiliation(s)
- Carlo Romano
- Palaeontological Institute and Museum, University of Zurich, Karl Schmid-Strasse 4, 8006, Zurich, Switzerland
| | - Martha B Koot
- School of Geography, Earth and Environmental Sciences (Faculty of Science and Technology), Plymouth University, Fitzroy Building, Drake Circus, Plymouth, Devon, PL4 8AA, U.K
| | - Ilja Kogan
- Department of Palaeontology, Geological Institute, TU Bergakademie Freiberg, Bernhard-von-Cotta-Strasse 2, 09596, Freiberg, Germany
| | - Arnaud Brayard
- UMR CNRS 6282 Biogéosciences, Université de Bourgogne, 6 Boulevard Gabriel, F-21000, Dijon, France
| | - Alla V Minikh
- Department of Historic Geology and Palaeontology, Saratov State University, 83 Astrakhanskaya Street, Saratov, 410012, Russia
| | - Winand Brinkmann
- Palaeontological Institute and Museum, University of Zurich, Karl Schmid-Strasse 4, 8006, Zurich, Switzerland
| | - Hugo Bucher
- Palaeontological Institute and Museum, University of Zurich, Karl Schmid-Strasse 4, 8006, Zurich, Switzerland.,Department of Earth Sciences, ETH Zurich, Sonneggstrasse 5, 8092, Zurich, Switzerland
| | - Jürgen Kriwet
- Department of Palaeontology, University of Vienna, Geozentrum, Althanstrasse 14, 1090, Vienna, Austria
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