THE FIRST ARTICULATED SKELETON OF DENDRERPETON ACADIANUM (TEMNOSPONDYLI, DENDRERPETONTIDAE) FROM THE LOWER PENNSYLVANIAN LOCALITY OF JOGGINS, NOVA-SCOTIA, AND A REVIEW OF ITS RELATIONSHIPS

The discovery of the first articulated, well-preserved specimen cf Den drerpeton acadianum makes it possible to describe this taxon completel y for the first time, and reassess its phylogenetic relationships. Lar ge laterally facing orbits, large, rounded squamosal embayments, absen ce of lateral line sulci, a short presacral column of only 24 vertebra e that is less than twice thr length of the skull, and large stout lim bs all suggest a terrestrial lifestyle distinct from the aquatic and s emiaquatic adaptations of most contemporary Carboniferous amphibians. Although Dendrerpeton bears a general resemblance to the highly terres trial dissorophoid temnospondyls and even shares with them a large squ amosal embayment supported ventrally by the quadratojugal and a quadra te process, phylogenetic analysis does not support a sister-group rela tionship. Rather Dendrerpeton is best considered the primitive sisterg roup of a clads of temnospondyls including trimerorhachoids, ''eryopoi ds'' (Eryops, Parioxys, and Sclerocephalus), zatracheids, and dissorop hoids.