Hexabdella, a new mite genus of Bdellidae (Acari: Prostigmata) from southern Africa, with descriptions of five new species

Members of the family Bdellidae inhabit a variety of habitats worldwide and are active predators of small arthropods_ Studies by Muma (1975) indicated that Bdella distincta (Baker & Balock) prey on eggs and crawlers of armoured scale insects on citrus in Florida, while Neomolgus capil/atus (Kramer) is associated with pasture pests from Scandinavia to Morocco (Wallace 1974). Bdellodes lapidaria (Kramer) was introduced successfully into South Africa to control lucerne flea (Sminthurus viridis (L.» in the Western Cape in 1973 (Wallace & Walters 1974). Sorensen et al. (1983) showed that Bdella longicornis (L.) collected from vine bark in California, USA, preceded the resident phytoseiid predators and contributed to the control of vine spider mite (Tetranychus pacificus McGregor). Neomolgus capil/atus (Kramer) effectively controlled autumn populations of lucerne flea, a serious pest of pastures in Tasmania (Ireson et al. 2002). Detailed accounts of the biological control status of bdellid species are provided by Gerson & Smiley (1990) and Gerson et al. (2003). The Bdellidae consists of five subfamilies (Van der Schyff et al. 2003) and the new genus Hexabdella is the second genus in the subfamily Bdellinae. Hexabdella is clearly defined by five new species described here from southern Africa. Hexabdella differs from the type genus, Bdella, by the absence of a trichobothrium on tarsus IV. Bdella mexicana Baker & Balock, a species recorded from Mexico and Hawai (Swift & Goff 1987), also lacks a trichobothrium on tarsus IV. It is here transferred to the new genus as Hexabdella mexicana comb. nov.