Distribution: Costa Rica and El Salvador.

Composition: The single species in the genus Irazua was described from three specimens from El Salvador and Costa Rica that were collected between 1955 and 1988. No additional specimens have since been collected, attesting to the rarity of this scarab.            

Diagnosis: The genus is characterized by tridentate protibiae, bidentate mandibles visible in dorsal view, clypeal apex emarginate and lobed either side of emargination, triangularly expanded eye canthus, strongly bifurcate head horn in the males, elytra completely and coarsely roughened, apex of mesotibia with single tooth, apex of metatibia with rounded lobe and triangular upper angle, and prosternal process short and indistinct.

In gestalt, it resembles those species of Heterogomphus with roughened elytra, except that the protibia is quadridentate in Heterogomphus and tridentate in Irazua. In addition, Irazua has a nearly obsolete prosternal process (instead of well-developed as in Heterogomphus), strongly bilobed mandibles (present only in H. julus Burmeister from southern Brazil), and an extremely setose (almost fur-like) pygidium (not known in any Heterogomphus species). Like the species in the subgenus Daemonoplus of Heterogomphus, the apex of the middle tibia ends in a single tooth rather than two teeth as in all the other species of Heterogomphus. The triangularly expanded eye canthus is dissimilar to virtually all other New World dynastines. Only Aceratus (Pentodontini: southern South America) and Barutus (Oryctini: Panama and Costa Rica) have an expanded eye canthus, but none have it developed to the degree as in Irazua. Females are probably similar but lack the horns. The most important questions about body morphology for the females are “one or two tubercles on the head?” and “what is the form of the pronotum?” Females cannot be reliably worked into a key to genera until these facts are known.

Biological notes: So far as known, adults are nocturnal and are attracted to lights.