The thickhead ground snake (Atractus crassicaudatus) is a nonvenomous colubrid snake species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

. There are no recognized subspecies.

Description

The thickhead ground snake is dark purplish brown or blackish both dorsally and ventrally, with small yellowish spots dorsally, and larger ones ventrally. The first row of dorsal scales, next to the ventrals on each side, is yellowish. There is a yellowish blotch on each temple.

Snout obtuse. Rostral small; internasals very small; prefrontals as long as broad; frontal as long as or a little longer than broad, as long as its distance from the end of the snout, much shorter than the parietals; loreal at least twice as long as high; two postoculars; temporals 1+2; seven upper labials (rarely six), third and fourth (or third) entering orbit; three lower labials in contact with the single pair of chin shields. Dorsal scales smooth, in 17 rows. Ventrals 146-161; anal entire; paired subcaudals 19-27.

Adults may attain 42 cm (16½ inches) in total length. The length of the tail is about 1/10 of the total length.