Barreras Fanged Snake

Ialtris agyrtes is a small species of Ialtris with a nearly patternless, brown to tan dorsum. A pale whitish supralabial line is present, extending from the tip of the snout to the base of the head, and with a darker brown superior margin. The venter is also patternless, nearly white, and grading posteriorly to pale orange.

Ialtris agyrtes is only known from three localities. Its range includes the southern foothills of the Sierra de Bahoruco mountain range in the Barahona Peninsula; as well as the lower elevations of Sierra Martín Garcia National Park. In these three locations the habitat is very similar, suggesting this species might be a specialist, inhabiting mid-elevation dry forests. The altitudinal distribution recorded is 20 to 541 m (66 to 1,775 ft). Specimens have been found under stones, and organic debris including the decaying rosettes of dead Agave, which are particularly abundant in its habitat.

The diet of Ialtris agyrtes is known to include blind-snakes (family Typhlopidae), and it has been hypothesized that this species could have a specialized ophiophagous diet of fossorial snakes. Other blind-snakes of the genus Mitophis (family Leptotyphlopidae), as well as snake-like lizards (Wetmorena agasepsoides) are known to be sympatric with I. agyrtes and could be part of its diet as well. Another species of the same genus, Ialtris haetianus, is considered to be a specialist feeding on frogs of the genus Eleutherodactylus, along with their eggs. Since frogs are very abundant in the cloud forest habitat of I. haetianus, and blind-snakes are very abundant in the dry forest habitat of I. agyrtes, it could be considered that these to snakes occupy similar niches in distinct habitats.

The specific name, agyrtes, has Greek origin, translating to "mimic, cheat", and bears reference to the superficial resemblance of this species to the related Ialtris parishi.