The Omilteman small-headed rattlesnake is endemic to Guerrero, Mexico, in the Sierra Madre del Sur highlands. It is a small rattlesnake averaging about two feet long. It is differentiated from other subspecies of C. intermedius by its ventral scale count: 164+ in males, and 170+ in females. This species is usually a dark gray or brown, with molted patterns of a darker tone; but completely melanistic specimens are often encountered in parts of its small range.

It inhabits montane humid pine-oak forests with abundant rocky ground cover and sun spots. Analysis of stomach contents reveal that this subspecies of rattlesnake feeds almost entirely on lizards.

Little else is known about the ecology of this small-ranging species, and more research is needed into reproduction, movement, and how it interacts with its environment.