International Centre of Future Science, Dinosaur Evolution Research Center, Jilin University, Changchun, China.
Department of Biology, University of Toronto at Mississauga, Mississauga, Ontario, Canada.
PeerJ. 2024 Nov 14;12:e18394. doi: 10.7717/peerj.18394. eCollection 2024.
Upper Permian rocks of the former supercontinent Gondwana record climax late Paleozoic terrestrial vertebrate faunas that were dominated numerically and ecologically by therapsid synapsids. Older faunal elements of earlier Paleozoic faunas, such as captorhinid reptiles, are rare and scattered components of the first amniote faunas to inhabit high-latitude regions. Here we describe a new genus and species of moradisaurine captorhinid that represents an archaic faunal element of the high-fibre herbivore fauna of the late Permian of what is now peninsular India. The presence of a relatively broad parietal and three rows of conical teeth on the maxilla and the dentary distinguishes gen. et sp. nov. from other moradisaurines. The hypodigm of comprises skulls that range in length from 39 mm to 54 mm, and high ossification of the braincase elements and well developed skull-roof sutures, indicate that adults were smaller than those of most moradisaurines. Results of our phylogenetic analyses suggest that moradisaurines, despite appearing first in the paleotropics, dispersed into temperate, high-latitude regions of Pangea early in their evolutionary history. Moradisaurines in dicynodont-dominated faunas, viz. and , were the smallest high-fibre herbivores in their respective faunas. This suggests that small body size may have evolved in these moradisaurines as they co-evolved with the more numerous and diverse dicynodont therapsids.
冈瓦纳古陆的上二叠统岩石记录了晚古生代陆地脊椎动物群的鼎盛时期,这些动物群在数量和生态上以合弓类兽孔目动物为主。更早的古生代动物群的古老动物群元素,如 captorhinid 爬行动物,是最早栖息在高纬度地区的初龙形类动物群中罕见和分散的组成部分。在这里,我们描述了一种新的 moradisaurine captorhinid 属和种,它代表了现在印度半岛晚二叠世高纤维食草动物群中古老的动物群元素。相对宽阔的顶骨和上颌骨和齿骨上的三排圆锥形牙齿的存在将 gen. et sp. nov. 与其他 moradisaurines 区分开来。 由头骨长度从 39 毫米到 54 毫米不等的标本组成,并且脑壳元素的高度骨化和发育良好的头骨 - 屋顶缝合线表明 成年个体比大多数 moradisaurines 小。我们的系统发育分析结果表明,尽管 moradisaurines 最初出现在热带地区,但它们在其进化历史的早期就已经分散到泛古陆的温带高纬度地区。在双孔类动物占主导地位的动物群中,如 和 ,moradisaurines 是各自动物群中最小的高纤维食草动物。这表明,这些 moradisaurines 可能随着与更多样化的双孔类合弓类动物的共同进化而进化出较小的体型。