DICYRTOCERCYON GANGLBAUER, 1904 (COLEOPTERA: HYDROPHILIDAE) IN BELARUS

Abstract

Morphological diagnosis, distribution and environmental preferences of genus Dicyrtocercyon Ganglbauer, 1904 are presented. The subgenus Dicyrtocercyon was described from Czechia. It is distributed in the Holarctic region. As a result of the study, the taxonomic status of subgenus Dicyrtocercyon is raised to the level of a genus. Dicyrtocercyon stat. nov. is a Cercyon-form genus from subfamily Sphaeridiinae, tribe Megasternini. This is indicated by the significant similarity of morphological signs, primarily with real Cercyon (C. marinus Thomson, 1853, C. quisquilius (Linnaeus, 1761), C. nigriceps (Marsham, 1802) etc.). The characteristic diagnostic morphological feature is that pronotum and elytra are separately convex in lateral view. Currently, the genus includes only one species Dicyrtocercyon ustulatus (Preyssler, 1790) comb. nov. It is most similar in coloration, size and body shape to species from the C. marinus group (С. marinus Thomson, 1853 and C. bifenestratus Kűster, 1851) in the Belarusian fauna. This species has black maxillary palpi and mesoventral plate wider (ca. 2.5—3.2× as long as wide in C. marinus and 1.9—2.0 in C. bifenestratus). Mesoventral plate is narrower in D. ustulatus (ca. 4.0—4.2× as long as wide). The best distinguishing features are that lateral view of pronotum does not form a continuous curve with elytra and elytra epipleura is narrow slightly wedge-shaped, slightly bent downwards at anterior half of the elytron. Species C. marinus group have flat epipleura and lateral view of pronotum forming a continuous curve with elytra.
D. ustulatus is a detritobiont and inhabits various water bodies, as well as waterfowl nests, beaver and muskrat lodges.