A new species of Atractus (Serpentes: Dipsadidae) from Serra do Cipó, Espinhaço Range, Southeastern Brazil, with proposition of a new species group to the genus.

Abstract

We describe a new species of Atractus from Serra do Cipó, at the southeastern versant of Serra do Espinhaço, an inland mountain range nearly parallel to the Brazilian Atlantic coast. The new species is morphologically similar to A. paraguayensis and A. potschi with which it shares: 15 dorsal scale rows; white occipital region in juvenile specimens; dorsal ground color reddish pink to red (in life) with alternate black transversal spots, blotches or transversal bands; seven upper and lower labial scales; ventrals and subcaudals creamish white; hemipenis slightly bilobed, semicapitate and semicalyculate. The new species differs from both taxa mainly on the basis of exclusive coloration characters (number and shape of transversal bands) and hemipe nial morphology (median face of the lobes without ornamentation), besides punctual meristic (number of ventral scales and maxillary teeth) and morphometric (adult snout-vent length) differences. Finally, we provide a discussion regarding the potential affinities of the new species and we redefine some Atractus species groups in order to better accommodate species sharing unique combinations of morphological characters.