Anatomy and relationships of the family Phlegethontiidae (Amphibia, Aistopoda)

Abstract

The cranial and cervical osteology of the middle Pennsylvanian a'istopod amphibian Phlegethantia linearis Cope, from Linton, Ohio, is described, Aomerpeton mazonense (Gregory), new genus. and Sillerpelan permianum, new genus and species, are compared and contrasted with P. linearir in endocranial structure and in the functional anatomy of their feeding mechanisms The feeding mechanism of Phlegethontia linearis is investigated, It displays cranial kinesis with unilateral jaw movements, in a manner analogous to that of snakes. The articulations of upper and lower jaws indicate a capacity to ingest large prey items, the reduction of the gastralia may have facilitated surficient ventral distention of the body to compensate for a lack of lateral palatal mobility The Phlegemontiidae and Ophiderpetontidae show widely divergent cranial specializav tions but are related on the basis of their common and uniquely derived postcranial characters. The Aistopoda cannot be derived from or closely related to any presently known amphibian group.