Ribalaius

Ribalaius is a genus of ground beetles in the family Carabidae. It was first described in 1995 by entomologist Ana Morales from specimens collected in the montane forests of the central Andes. The genus is currently known from a limited number of localities in South America, and it is considered small in both species richness and geographic range.

The genus includes three described species: Ribalaius ribiformis, Ribalaius montanus, and Ribalaius pacificus. Adults range from 6 to 9 millimeters in length and have an elongate body shape. Diagnostic features include strongly ribbed elytra with transverse ridges, a smooth to finely punctate pronotum, and a dark brown to black coloration with a subtle bluish or greenish sheen in some individuals. The legs are slender, with the front femora slightly enlarged in some populations.

Ribalaius beetles are typically found in leaf litter and under fallen logs within montane forests at elevations roughly between 1200 and 2600 meters. They are nocturnal predators of small invertebrates and are often associated with moist microhabitats that retain humidity. Flight is limited in adults, which contributes to their patchy distribution and localized populations.

Conservation status varies by locality, with several populations known from single or few localities. Habitat loss due to deforestation and agricultural expansion poses a ongoing threat. The genus is of interest to biogeographers studying Andean forest ecosystems and to taxonomists surveying Carabidae diversity in montane habitats.