THE OLDEST KNOWN STEGOCEPHALIAN (SARCOPTERYGII: TEMNOSPONDYLI) FROM SPAIN
Résumé
More data are provided on the recently described temnospondyl Iberospondylus schultzei from the Upper Carboniferous (Stephanian C) of the Spanish Puertollano Basin. It represents the only known occurrence of a Paleozoic stegocephalian in a Spanish basin. This taxon appears to be more closely related to eryopoids and dissorophoids than to edopoids, as shown by four synapomorphies. However, decay index and bootstrap analyses show that the presented phylogeny, like other recently published phylogenies of temnospondyls, is not robust. Recently published phylogenetic data do not resolve the position of Dendrerpeton in temnospondyl phylogeny. Iberospondylus appears to have lived in the coastal marine environment in which it was preserved. The Spanish material supports the suggestion that the temnospondyls were sometimes coastal, near-marine animals. The widely held idea that many temnospondyls possessed a tympanum is poorly documented; the stapes of this group is always more massive than that of similarly-sized extant tetrapods that possess a tympanum. Other arguments presented to support the presence of a tympanum in temnospondyls appear to be invalid. Therefore, the widely held thesis that a tympanum was present in temnospondyls is questioned.