ABSTRACT

The fossil record of early diapsids is sparse, specimens are uncommon and often incomplete, and phylogenetic relationships are hard to determine. A new taxon of early diapsid, Feralisaurus corami from the Middle Triassic of Devon, south-western England, is here named and described from an incomplete but mostly articulated skeleton, comprising skull, vertebrae, pectoral girdle, ribs, and the right forelimb. CT scanning and the resultant 3D model of the skeleton reveal anatomical details otherwise buried in the sandstone matrix. This new diapsid is characterized by a plesiomorphically high maxilla without a prominent nasal process, a quadrate with a lateral conch, a low jugal with small posterior process, conical teeth with pleurodont implantation, a high coronoid process, notochordal vertebrae, a long humerus with an entepicondylar foramen, rod-like clavicles, a ‘T’-shaped interclavicle, and a ventrolateral process of the scapulocoracoid. Phylogenetic analyses, although showing generalized weak support, retrieved Feralisaurus within Neodiapsida or stem-group Lepidosauromorpha: its morphology supports the latter hypothesis. This specimen adds to our knowledge of the early diversification of Lepidosauromorpha and of English Middle Triassic terrestrial faunas.

摘要

早期胡闹的化石记录稀疏，标本罕见且常常不完整，并且系统发育关系很难确定。早熟的一种新的分类群，Feralisaurus corami来自英格兰西南部德文郡的中三叠纪，这里的名称和描述来自一个不完整但大部分是铰接的骨骼，包括头骨，椎骨，胸带，肋骨和右前肢。CT扫描和生成的骨骼3D模型揭示了解剖细节，否则这些细节将被埋在砂岩基质中。这种新的diapsid的特征是上颌骨形态复杂，上颌突突不突出，四边形具有侧向海螺，下颌骨呈低齿状，后突较小，圆锥形牙齿有胸膜齿植入，冠状突高，脊索椎骨，肱骨长， icon突孔，棒状锁骨，“ T”形锁骨和肩or囊腹侧突。系统发育分析，尽管显示出普遍的弱支持，检索Neodiapsida或茎类鳞翅类中的铁龙：其形态支持后一种假说。这个标本增加了我们对鳞翅目和英国中三叠纪陆生动物群早期多样化的认识。