Thorn K M, Hutchinson M N, Lee M S Y, Brown N J, Camens A B, Worthy T H
College of Science and Engineering, Flinders University, Bedford Park 5042, South Australia.
South Australian Museum, North Terrace, Adelaide 5000, South Australia.
R Soc Open Sci. 2021 Feb 17;8(2):201686. doi: 10.1098/rsos.201686.
The diverse living Australian lizard fauna contrasts greatly with their limited Oligo-Miocene fossil record. New Oligo-Miocene fossil vertebrates from the Namba Formation (south of Lake Frome, South Australia) were uncovered from multiple expeditions from 2007 to 2018. Abundant disarticulated material of small vertebrates was concentrated in shallow lenses along the palaeolake edges, now exposed on the western of Lake Pinpa also known from Billeroo Creek 2 km northeast. The fossiliferous lens within the Namba Formation hosting the abundant aquatic (such as fish, platypus and waterfowl) and diverse terrestrial (such as possums, dasyuromorphs and scincids) vertebrates and is hereafter recognized as the Fish Lens. The stratigraphic provenance of these deposits in relation to prior finds in the area is also established. A new egerniine scincid taxon sp. nov. described herein, is based on a near-complete reconstructed mandible, maxilla, premaxilla and pterygoid. Postcranial scincid elements were also recovered with this material, but could not yet be confidently associated with . This new taxon is recovered as the sister species to , in a tip-dated total-evidence phylogenetic analysis, where both are recovered as stem Australian egerniines. These taxa also help pinpoint the timing of the arrival of scincids to Australia, with egerniines the first radiation to reach the continent.
澳大利亚现存蜥蜴动物群种类多样，这与它们有限的渐新世 - 中新世化石记录形成了鲜明对比。2007年至2018年的多次考察中，在南澳大利亚弗罗梅湖以南的南巴组发现了新的渐新世 - 中新世化石脊椎动物。大量小型脊椎动物的零散化石集中在古湖边缘的浅层透镜状地层中，现在这些地层出露在平帕湖西部，在东北2公里处的比勒罗溪也有发现。南巴组中含有丰富水生动物（如鱼类、鸭嘴兽和水禽）和多样陆生动物（如负鼠、袋鼬目动物和石龙子科蜥蜴）化石的透镜状地层，此后被认定为鱼类透镜状地层。还确定了这些沉积物相对于该地区先前发现的地层来源。本文描述的一个新的艾氏石龙子科蜥蜴新分类单元，基于一个近乎完整重建的下颌骨、上颌骨、前颌骨和翼骨。与该材料一起还发现了石龙子科蜥蜴的颅后骨骼，但尚不能确定它们与该新分类单元的关联。在一个时间校准的全证据系统发育分析中，这个新分类单元被认定为某种蜥蜴的姐妹物种，两者都被认定为澳大利亚艾氏石龙子科蜥蜴的基干类群。这些分类单元也有助于确定石龙子科蜥蜴到达澳大利亚的时间，艾氏石龙子科蜥蜴是最早到达该大陆的辐射类群。
