The first temnospondyl amphibian from Japan

Abstract

Staatliches Museum fur Naturkunde Rosenstein 1, 70191 Stuttgart, Germany,¨schoch.smns@naturkundemuseum-bw.deTemnospondyls are the most diverse, speciose, and long-livedgroup of early tetrapods. Whereas their first record in the latePaleozoic is restricted to Euramerica, during the early Meso-zoic they reached an almost worldwide distribution. The large,crocodiliform stereospondyls in particular experienced a phaseof rapid dispersal across vast areas of the Pangean superconti-nent (Schoch, 2000). Rich deposits have been reported from theEarly and Middle Triassic of Arizona, Argentina, Brazil, Cen-tral Europe, European Russia, South Africa, India, Madagascar,and Australia (Schoch and Milner, 2000). However, in East Asiatheir remains are still very rare and utterly fragmentary (Lucasand Hunt, 1993; Liu and Wang, 2005). At the same time, the pa-leogeography of the eastern Pangean margin is still rather poorlyunderstood, which hampers a clear picture of migratory patternsof aquatic tetrapods during the early Mesozoic. In this paper, wereport the occurrence of a capitosauroid taxon in the Lower Tri-assic of northeastern Honshu, Japan. This is not only the firsttemnospondyl from the Japanese islands but also forms the firstnon-marinevertebrate fromthe Triassicof Japan, which suggestsa migration of aquatic tetrapods across the land bridge betweenthe North China block and the ancient Japanese islands in pre-Jurassic time.SYSTEMATIC PALEONTOLOGYTEMNOSPONDYLI Zittel, 1887–1890 (sensu Milner, 1990)STEREOSPONDYLI Watson, 1919 (sensu Milner, 1994)CAPITOSAUROIDEA Watson, 1919 (sensu Schoch andMilner, 2000)