Revision of the basal sphenacodonts (Haptodontinae): systematic and evolutionary implications

早期陆生四足动物群中以非兽头类棘齿为主。这一成功始于被称为粘齿兽的基底棘齿兽（以前的粘齿亚科，模式属）。据报道，它们的化石从宾夕法尼亚晚期到二叠纪早期，分布在北美、英国和欧洲大陆。只有少数物种以现代方式被描述过。许多描述可以追溯到1886年至1925年之间（H. baylei, palaehatteria, Callibrachion， Datheosaurus和Pantelosaurus），因此必须根据新的证据进行修订。此外，除了解剖特征外，对它们的进化知之甚少。本项目旨在记录触齿兽的特征多样性，从而进行分类修订。此外，这是古生物学（包括个体发生学）、生态学和系统发育学结论的基础。利用描述、分支学和比较动物学方法（解剖学、个体发生学、功能形态学），这将是首次对触齿动物进行完整的研究，对了解哺乳动物前的四足动物具有重要意义。特别令人感兴趣的是古长尾龙（Palaeohatteria longicaudata Credner 1888）的修订，它只从幼年骨骼中得知，并将其与附近地区的萨克森潘特龙（Pantelosaurus saxonicus von Huene 1925）进行比较。因此，该项目将基于对所有触齿兽化石的研究，生成一个完整的群体特征，包括系统学、古生物学和它们的地层分布。

Non-therapsid sphenacodonts dominate the early terrestrial tetrapod assemblages. This success began with the basal Sphenacodontia, referred to as haptodonts (previous subfamily Haptodontinae, type genus Haptodus). Their fossils are reported from the Late Pennsylvanian to the Early Permian from North America, England and continental Europe. Only few species have been described the modern way. Many descriptions date back between 1886 and 1925 (H. baylei, Palaeohatteria, Callibrachion, Datheosaurus, and Pantelosaurus) and therefore have to be revised based on new evidence. Furthermore, little is known about their evolution apart from the anatomical characters. This project aims to record the haptodont’s character diversity, leading to a taxonomical revision. Further, this is the basis for palaeobiological (including ontogenetical), ecological and phylogenetic conclusions. Using descriptive, cladistic and comparative zoological methods (anatomy, ontogeny, functional morphology), it will be the first complete study of haptodonts, important for understanding pre-mammal tetrapods. Of special interest is the revision of Palaeohatteria longicaudata Credner 1888, known from juvenile skeletons only, and its comparison to Pantelosaurus saxonicus von Huene 1925 from a nearby locality. As a result, the project will generate a complete characterization of the group, based on the study of all haptodont fossils, containing systematics, palaeobiology and their stratigrafic distribution.