A Review of the Colubrid Snake Genus Amastridium
Analysis of 18 characteristics of scutellation, osteology, coloration, and body measurement indicates that the characteristics used to distinguish Amastridium veliferum and A. sapperi are disconcordant. Numbers of ventrals and maxillary teeth vary clinally from high numbers in the northern portion of the range to low numbers in the southern portion. Specimens north of and including Honduras have a loreal scale, while those south of Honduras lack this scale. Specimens from Panama have a lighter dorsal and ventral coloration and more prominent light lateral spots than those from the remainder of the range. Grooving of the rear teeth is not characteristic of all specimens of "sapperi" as purported by previous authors. In view of the disconcordant nature of these characteristics and the absence of additional distinguishing features to complement any of the other variable characteristics, we prefer to recognize only a single species, veliferum, in the genus Amastridium. Intergeneric relationships of Amastridium are obscure, but the genus does not appear to be closely related to any other Middle American group.
Wilson, Larry David and Meyer, John R.
"A Review of the Colubrid Snake Genus Amastridium,"
Bulletin of the Southern California Academy of Sciences:
Available at: http://scholar.oxy.edu/scas/vol68/iss3/5