Living fast in the Triassic: New data on life history in Lystrosaurus (Therapsida: Dicynodontia) from northeastern Pangea.

Autor: Kulik ZT; Department of Biology and Burke Museum, University of Washington, Seattle, WA, United States of America., Lungmus JK; Smithsonian National Museum of Natural History, Washington, D.C., United States of America., Angielczyk KD; Negaunee Integrative Research Center, Field Museum of Natural History, Chicago, IL, United States of America., Sidor CA; Department of Biology and Burke Museum, University of Washington, Seattle, WA, United States of America.
Jazyk: angličtina
Zdroj: PloS one [PLoS One] 2021 Nov 05; Vol. 16 (11), pp. e0259369. Date of Electronic Publication: 2021 Nov 05 (Print Publication: 2021).
DOI: 10.1371/journal.pone.0259369
Abstrakt: Lystrosaurus was one of the few tetrapods to survive the Permo-Triassic mass extinction, the most profound biotic crisis in Earth's history. The wide paleolatitudinal range and high abundance of Lystrosaurus during the Early Triassic provide a unique opportunity to investigate changes in growth dynamics and longevity following the mass extinction, yet most studies have focused only on species that lived in the southern hemisphere. Here, we present the long bone histology from twenty Lystrosaurus skeletal elements spanning a range of sizes that were collected in the Jiucaiyuan Formation of northwestern China. In addition, we compare the average body size of northern and southern Pangean Triassic-aged species and conduct cranial geometric morphometric analyses of southern and northern taxa to begin investigating whether specimens from China are likely to be taxonomically distinct from South African specimens. We demonstrate that Lystrosaurus from China have larger average body sizes than their southern Pangean relatives and that their cranial morphologies are distinctive. The osteohistological examination revealed sustained, rapid osteogenesis punctuated by growth marks in some, but not all, immature individuals from China. We find that the osteohistology of Chinese Lystrosaurus shares a similar growth pattern with South African species that show sustained growth until death. However, bone growth arrests more frequently in the Chinese sample. Nevertheless, none of the long bones sampled here indicate that maximum or asymptotic size was reached, suggesting that the maximum size of Lystrosaurus from the Jiucaiyuan Formation remains unknown.
Competing Interests: The authors have declared that no competing interests exist.
Databáze: MEDLINE
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