Revision of the Neotropical water scavenger beetle genus Guyanobius Spangler (Coleoptera: Hydrophilidae: Chaetarthriini)

The Neotropical water scavenger beetle genus Guyanobius Spangler 1986, characterized by its partially divided eyes, is revised and expanded to accommodate two newly discovered species. The genus previously contained two described species: Guyanobius adocetus Spangler, 1986 from Guyana and Venezuela and Guyanobius simmonsorum Spangler, 1990 from Brazil. The two newly discovered species, from Venezuela and French Guiana and Suriname respectively, occur in small forest streams. A key to the species of Guyanobius is provided as well as illustrations of diagnostic characters. The prior concept of G. adocetus was composite with respect to one of the newly discovered taxa. A new Andean locality for Guyanobius extends the range of the genus by more than 1200 km and far outside the Guyana shield.