Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa.
Department of Palaeobiology, Swedish Museum of Natural History, Stockholm, Sweden.
PLoS One. 2023 Mar 29;18(3):e0282354. doi: 10.1371/journal.pone.0282354. eCollection 2023.
Large-bodied temnospondyl amphibians were the dominant predators in non-marine aquatic ecosystems from the Carboniferous to the Middle Triassic. In the Permian-aged lower Beaufort Group of the main Karoo Basin, South Africa, temnospondyls are represented exclusively by the family Rhinesuchidae and are well represented by body fossils, whereas trace fossils are scarce. Accordingly, most interpretations of the behaviour of this family are based on skeletal morphology and histological data. Here we document the sedimentology and palaeontology of a late Permian palaeosurface situated immediately below the palaeoshoreline of the Ecca Sea (transition from the Ecca Group to the Beaufort Group) near the town of Estcourt in KwaZulu-Natal Province. The surface preserves numerous ichnofossils, including tetrapod footprints and fish swim-trails, but most striking are seven body impressions and associated swim trails that we attribute to a medium-sized (~1.9 m long) rhinesuchid temnospondyl. These provide valuable insight into the behaviour of these animals. The sinuous shape of some of the traces suggest that the tracemaker swam with continuous sub-undulatory propulsion of the tail.
大型的坚头类两栖动物是从石炭纪到中三叠世非海洋水生生态系统中的主要掠食者。在南非主卡里布盆地的二叠纪年龄较低的比福特组中，坚头类动物仅由 Rhinesuchidae 科代表，并有大量的身体化石，而痕迹化石则很少。因此，对该科动物行为的大多数解释都是基于骨骼形态和组织学数据。本文记录了位于埃卡海（从埃卡组到比福特组的过渡）古海岸线下方的晚二叠世古地表的沉积学和古生物学，该古地表位于夸祖鲁-纳塔尔省的埃斯科特镇附近。该表面保存了许多遗迹化石，包括四足动物足迹和鱼类游泳痕迹，但最引人注目的是七个身体印痕和相关的游泳痕迹，我们将其归因于一种中等大小（约 1.9 米长）的 Rhinesuchidae 坚头类动物。这些为研究这些动物的行为提供了有价值的见解。一些痕迹的弯曲形状表明，痕迹制造者通过尾巴的连续次波状推进来游泳。
