Data from: A new Mississippian tetrapod from Fife, Scotland, and its environmental context

The Visean stage of the Mississippian was a time of rapid tetrapod diversification which marks the earliest appearance of temnospondyls, microsaurs and the limbless aïstopods. Tetrapod finds from this stage are very rare and only a dozen sites are known worldwide. Here we announce the discovery of a new Visean site in Fife, Scotland, of Asbian age, and from it describe a new species of the baphetoid Spathicephalus. These specimens represent the oldest known baphetoid by three million years, yet belong to the most specialized members of the clade. Unlike typical baphetoids with large marginal teeth and palatal fangs characteristic of early tetrapods, spathicephalids had very broad flattened heads with a dentition consisting of a large number of small, uniform teeth. Spathicephalids were probably one of the earliest tetrapod groups to use suction feeding on small, aquatic prey. Palynological and sedimentological analysis indicates that the new fossil bed was deposited in a large, stratified, freshwater lake that became increasingly saline.密西西比纪（Mississippian）的维宪阶（Visean Stage）是四足动物（tetrapod）快速辐射演化的时期，该阶段标志着离片椎类（temnospondyls）、微蜥类（microsaurs）以及无肢螈类（aïstopods）的首次出现。此阶的四足动物化石记录极为稀缺，全球范围内仅发现十余处化石点。本文报道了苏格兰法夫郡一处新的维宪阶（阿斯布亚阶（Asbian Age））化石点，并对其中发现的巴菲蟾形类（baphetoid）铲头螈属（Spathicephalus）一新种进行了描述。该标本代表了目前已知最古老的巴菲蟾形类化石，其生存年代比此前记录的同类化石早三百万年，但却隶属于该演化支中特化程度最高的类群。与典型巴菲蟾形类具备早期四足动物标志性的大型边缘齿与腭尖牙不同，铲头螈科（spathicephalids）拥有极为宽阔扁平的头部，齿列由大量细小且形态均一的牙齿构成。铲头螈科可能是最早采用吸吮取食（suction feeding）方式捕食小型水生猎物的四足动物类群之一。孢粉学（palynology）与沉积学（sedimentology）分析显示，该化石层沉积于一处大型分层淡水湖泊中，该湖泊的盐度随时间逐渐升高。