New species of Helicops Wagler, 1830 (Serpentes, Colubridae) from Tapajós river, Amazon region, Brazil

Abstract

Within the 14 species of Helicops known, five of them are distributed in Brazilian Amazon region. Here I describe a new species of Helicops based on three specimens from Tapajós river, western Pará state, Brazil. The new species is characterized by an opaque, green-moss uniform coloration on the vertebral and paravertebral scales, extending until the end of the tail, becoming yellow-greenish in the paraventral region, without spots, blotches or stripes on the whole dorsum. It differs from all species known of Helicops by the dorsal color pattern. Morphologically, the new species seems like H. leopardinus (as indicated by the number of dorsal scale rows, the number of ventral scales, and the number of teeth), but it has smaller lobes in the hemipenis and a very distinct color pattern. Illustrations of the type material and a dicotomic key are presented to help to distinguish the new species from other species of Helicops from Brazilian Amazon region.