Chasmogenus is a Neotropical genus of water scavenger beetles belonging to the family Hydrophilidae.[1]
The genus Chasmogenus was described for the first time by David Sharp in 1882 for species from Guatemala and Panama.[2]
Since 1919 the genus Crephelochares (from the Old World) was considered a synonym of Chasmogenus,[3] but thanks to the results of a phylogenetic analysis involving molecular data,[4] both taxa are now considered distinct genera on their own right.[1]
Currently, a total of 36 species is identified and documented, most of them recorded from the Guiana Shield Region.
Small size (2.5–5.0 mm), bearing a clearly visible sutural stria; long maxillary palps; metafemora usually densely covered by hydrofuge pubescence. The external morphology in Chasmogenus is very uniform across species, so that most species can only be identified by the shape of the male genitalia.
By the presence of the sutural stria, in the Neotropical region, Chasmogenus can only be confused with some members of the genus Primocerus.[1]
According to Girón and Short:[1]
The vast majority of Chasmogenus are known from forested habitats, including the margins of streams and forest pools. A few species are known from open marsh habitats (e.g., Chasmogenus australis García and Chasmogenus sapucay Fernández). They can be found among the vegetation and submerged leaf litter. They are also attracted to lights, though usually not in large numbers. Only one species [Chasmogenus cremobates (Spangler)] has been collected in seepages.
— Girón and Short, The Acidocerinae (Coleoptera, Hydrophilidae): taxonomy, classification, and catalog of species
Chasmogenus is a Neotropical genus of water scavenger beetles belonging to the family Hydrophilidae.
Chasmogenus er en slekt av biller som hører til familien vannkjær (Hydrophilidae).
Små til middelsstore, ovale, blankt svarte vannkjær. Palpene er lange og tynne, mye lengre enn de spinkle antennene med en løs, tre-leddet klubbe.
Chasmogenus-artene lever i vegetasjonsrike ferskvann.