Helophorus ís the only genus in the beetle family Helophoridae (traditionally included within Hydrophilidae as the subfamily Helophorinae). They are small insects, found mainly in the Holarctic region (150 occur in Palearctic and 41 species in North America), but two or three species also live in the Afrotropical region, Central America and one in the Indomalayan region (northern India).
Length about 2–9 mm. Body elongate with outline more or less interrupted between pronotum and elytra. On pronotum they have granulate sculpture and unique pattern of 7 longitudinal grooves. Ventral surface is with fine microsculpture, pubescent. Larvae are with long 3 segmented urogomphi and simple (non lobate) 8th tergum. They have four-segmented legs and a 10 segmented abdomen (with the 10th segment being a bit reduced). Helophorus larvae may damage wheat, turnips, rutabagas, and rapeseed.
Systematics and evolution
Helophoridae belong to the superfamily Hydrophiloidea, and may be the sister taxon of Hydrochidae, or a clade comprising Hydrochidae, Hydrophilidae and Spercheidae or Georissidae and Epimetopidae. Earlier systems included all of these families in the family Hydrophilidae. There are about 180 living species, including:
The genus is divided into many subgenera (Atracthelophorus, Cyphelophorus,Empleurus, Eutrichelophorus, Gephelophorus, Helophorus, Orphelophorus, Rhopalohelophorus and Transithelophorus).
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- Mart, A, Erman, O., A Study on Helophorus Fabricius, 1775 (Coleoptera, Hydrophilidae) Species. Turk. J. Zool. 25 (2001) 35-40
- M.Hansen. Phylogeny and classification of the staphyliniform beetle families (Coleoptera). Biologiske Skrifter 48, Copenhagen, 1997
- E.Anton, R.G.Beutel, On the Head Morphology and Systematic Position of Helophorus (Coleoptera: Hydrophiloidea: Helophoridae.)Zoologischer Anzeiger - A Journal of Comparative Zoology, Vol.242, 4, 2004
- M.S.Caterino et al. On the constitution and phylogeny of Staphyliniformia (Insecta: Coleoptera), Molecular Phylogenetics and Evolution, Vol.34 - 3, 2005