Archerpeton anthracos from the Joggins Formation of Nova Scotia: a microsaur, not a reptile

Abstract

New anatomical information, provided by reinterpretation of the pectoral girdle and exposure of previously unprepared portions of the holotype, reveals that the early tetrapod Archerpeton anthracos (Westphalian A of Joggins, Nova Scotia) is a microsaurian lepospondyl, rather than a reptile, as originally described. Archerpeton anthracos is similar to another Joggins microsaur, Asaphestera intermedia, from which it is distinguished by autapomorphies of the appendicular skeleton. The discovery that A. anthracos is a microsaur increases the number of lepospondyls at Joggins to six species and reduces the number of amniotes to two species, Hylonomus lyelli and Protoclepsydrops haplous.