Hydrochus farsicus sp.n. from Iran and notes on other Palearctic species of the genus (Coleoptera: Hydrophiloidea: Hydrochidae)

Abstract

The family Hydrochidae (or subfamily Hydrochinae for some authors) includes one recognised genus (Hydrochus Leach) with more than 200 species and a worldwide distribution (Hansen, 1999; Short & Hebauer, 2006). The West Mediterranean is among the most diverse areas for the genus in the Palearctic Region, with 12 species known from Spain and Morocco, including several endemic species described recently (Hansen, 2004). On the contrary, in the East Mediterranean and the Middle East few species are known so far, although some undescribed species from Turkey are deposited in the Naturhistorisches Museum Wien (NMW). No species of Hydrochus has ever been recorded from Iran (Hansen, 2004). Other groups of aquatic Coleoptera (e.g. Dytiscidae, Nilsson, 2004 or Hydraenidae, Jäch, 2004) display a more balanced distribution of species, and include a high number of Turkish or Iranian endemics. The situation in Hydrochus may be due to lack of knowledge, as the undescribed specimens in the NMW and some recent works (Incekara et al., 2004; Mart et al., 2009) may suggest, but it may be that in Turkey and the Middle East the genus Hydrochus is generally less speciose than in the West Mediterranean. In this paper two species of Hydrochus are recorded from Iran, one of which is described as new. In addition, some taxonomic notes on other Palearctic species are provided.