The first articulated skeleton of Dendrerpeton acadianum (Temnospondyli, Dendrerpetontidae) from the Lower Pennsylvanian locality of Joggins, Nova Scotia, and a review of its relationships

ABSTRACT

The discovery of the first articulated, well-preserved specimen of Dendrerpeton acadianum makes it possible to describe this taxon completely for the first time, and reassess its phylogenetic relationships. Large, laterally facing orbits, large, rounded squamosal embayments, absence of lateral line sulci, a short presacral column of only 24 vertebrae that is less than twice the length of the skull, and large stout limbs all suggest a terrestrial lifestyle distinct from the aquatic and semiaquatic adaptations of most contemporary Carboniferous amphibians. Although Dendrerpeton bears a general resemblance to the highly terrestrial dissorophoid temnospondyls and even shares with them a large squamosal embayment supported ventrally by the quadratojugal and a quadrate process, phylogenetic analysis does not support a sister-group relationship. Rather, Dendrerpeton is best considered the primitive sistergroup of a clade of temnospondyls including trimerorhachoids, “eryopoids” (Eryops, Parioxys, and Sclerocephalus), zatracheids, and dissorophoids.