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We describe a striking new species of the lungless salamander family Plethodontidae from the Appalachian foothills of northern Georgia, USA. This miniature species, c. 25–26 mm (adult standard length), is so distinctive genetically and morphologically that we erect a new genus, the first new genus of amphibian described from the US in nearly 50 years. It is unique among plethodontids from eastern North America in displaying sexual colour dimorphism. Although certain miniaturized plethodontids exhibit a reduced number (four) of digits on the pes, this species possesses a full complement of five toes. A plethodontid phylogeny derived from mitochondrial and nuclear DNA sequences places it in the tribe Spelerpini as the sister taxon to Eurycea. Genetic divergence between the new species and Eurycea for the nuclear gene Rag-1 (4.7%) is among the higher levels observed between long-established spelerpine genera (2.6–5.3%). This new form appears to be rare and is of immediate conservation concern. [ABSTRACT FROM AUTHOR]

Recent surveys of the plethodontid salamander fauna of Oaxaca, Mexico, disclosed the existence of a new, morphologically distinct arboreal species of the genus Pseudoeurycea . The new species, described here, is from the Sierra Mazateca in northern Oaxaca. Sequences of 1833 base pairs of the 16S, cytochrome b and ND4 mitochondrial DNA (mtDNA) genes from the new taxon were used to assess its phylogenetic position. Previous phylogenetic analyses based on mtDNA supported recognition of four clades within Pseudoeurycea : P. bellii , P. gadovii , P. juarezi and P. leprosa-Lineatriton species groups. One additional species, P. unguidentis , was not closely allied to any of the four groups. Re-analysis including the additional sequences reported here establishes a sister-group relationship between the new species and P. unguidentis . Moreover, it supports this clade as part of the P. juarezi species group. [ABSTRACT FROM AUTHOR]