Platyparnus, a new genus of Dryopidae from the Guiana Shield (Coleoptera: Byrrhoidea, Dryopidae).

Platyparnus gen. n. is erected to include three species of Helichus Erichson, 1847, from the Guianas of northern South America. Proposed taxonomic reassignments are Platyparnus bollowi (Hinton, 1939) comb. n., Platyparnus frater (Hinton, 1939) comb. n, and Platyparnus gibbicollis (Hinton,1939) comb. n. A description of the previously unknown male of P. gibbicollis is provided. The males of these species exhibit unique, sexually dimorphic modifications of the legs. Included are figures illustrating external morphology and male genitalia of the species, images of the holotypes, and notes on habitat and behaviour. A taxonomic key to the species of Platyparnus gen. n. is furnished, as well as a key to all known aquatic and semiaquatic Neotropical dryopid genera. urn:lsid:zoobank.org:pub:A51F9960-7C35-44F4-9ADC-00C5EA08AC52 [ABSTRACT FROM AUTHOR]