Added 23 May 2007. Last updated 2 January 2024: updated page and added A. sapperi.

A Look at the Family Colubridae

Amastridium

Rustyhead Snake


Introduction

A small genus restricted to Central America.

For some time only one species was recognised, A. veliferum, with sapperi as a subspecies, but sapperi is now elevated to full species status. In their hemipenis, hypapophyses, coloration and habit the two species are identical, as are some other details.

Scientific Name

Common Name

Distribution

Size

Notes

Amastridium

A. sapperi

Rusty-Headed Snake

S Mexico, C Guatemala, Belize, N Honduras


Scalation details: loreal present; oculars 1-2, temporals 1-2; single nasal; 3rd and 4th labials enter the eye; 17 rows of smooth, pitless scales; ventrals 153-158. Teeth: maxillary 14, 16-2, groove visible under magnification of 80 diameters.

A. veliferum

Rufous-Headed Snake, Rustyhead Snake

Mexico (Nuevo Leon, Tamaulipas and Oaxaca to Chiapas), Belize, N Guatemala, Honduras, Costa Rica and Panama

SVL 30-45cm/12-18"

Apparently a rare species. It is terrestrial and feeds on frogs. In Yucatán it is found in humid lowland forests, coffee plantations and also at the mouth of caves or in the twilight zone thereof. The subspecies may not be completely accepted; one from northern part of range, one from southern. Scalation details: loreal absent; oculars 1-2, temporals 1-2; single nasal; 3rd and 4th labials enter the eye; 17 rows of smooth, pitless scales;dorsal scales smooth, in 17 rows at midbody; paired apical pits on anterior third of body; ventrals 121-135, anal plate divided. Teeth: maxillary 12-2, no groove visible under magnification of 80 diameters. Other: head notably distinct from neck; eyes relatively small, pupil round. Coloration: dorsally dark brown or grey, usually little or no pattern; some individuals have row of small white spots on scale row 5 every 4-5 scales; head usually lighter, rusty brown, with longitudinal dark lines dorsally and laterally; ventrally greyish-brown, becoming lighter anteriorly. Reproduction: males have supraanal tubercles; no other details available.  B I

A. v. veliferum

A. v. sapperi [now a full species: see above]

Bibliography

Field Guide to Amphibians and Reptiles of the Maya World, Julian C Lee, Cornell University Press, 2000.

Amastridium, a neglected genus of snakes”, E R Dunn, Proceedings of the United States National Museum, vol 65 no 11, 1925.

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