Molecular and morphological revision of Afrotropical Hypoborini (Coleoptera: Curculionidae: Scolytinae) revealed novel bark beetle taxa with narrow geographical distributions

Abstract

Species in the bark beetle tribe Hypoborini Nusslin, 1912 occur in dead twigs and branches, mainly in dry forest. The Afrotropical fauna previously included ten species in five genera. A taxonomic revision based on molecular and morphological data supports the description of three new genera and seven new species, and the creation of a new subtribe Xerasiborina Jordal, subtrib. n. in order to take account of the difference between crested and non-crested (elytral base) hypoborines. The new subtribe includes Xerasiborus Jordal, gen. n., Nisiborus Jordal, gen. n. and tentatively Glochiphorus Strohmeyer, 1910. Hypoborina in the Afrotropical region includes Dacryostactus Schaufuss, 1905, Styracoptinus Wood, 1962, Afrotrypetus Bright, 1982 stat. res., and Corditarsus Jordal, gen. n., with Hypoborus Erichson, 1836 and Liparthrum Wollaston, 1854 as geographically close members in the warm Palearctic. New species described are Xerasiborus quadrituberculatus Jordal, sp. n., Xerasiborus bituberculatus Jordal, sp. n., Xerasiborus euphorbiae Jordal, sp. n. and Xerasiborus asperatus Jordal, sp. n., all from Madagascar, Xerasiborus zambesianus Jordal, sp. n. from Tanzania, Nisiborus schaufussi Jordal, sp. n. from Madagascar and Afrotrypetus capensis Jordal, sp. n. from South Africa. New combinations include Nisiborus hylesiniformis (Schedl, 1961), comb. n. (from Cryphyophthorus Schedl, 1953), Corditarsus australis (Schedl, 1975) comb. n. (from Liparthrum), Corditarsus tanganyikaensis (Schedl, 1972) comb. n. (from Hypoborus) and Afrotrypetus euphorbiae Bright, 1981 comb. res. (from Styracoptinus). Three genera were removed from Hypoborini: Chaetophloeus LeConte, 1876 and placed in Chaetophloeini Jordal, trib. n., Zygophloeus Schedl, 1958 in Hylesinini Erichson, 1836 and Cryphyophthorus Schedl, 1953 as a genus incertae sedis. Biogeographical analyses indicate an early Palaeocene origin of Hypoborini, with an ancestral area split between Asia/Africa and Madagascar. Only a single colonization of Madagascar occurred, with a single recolonization of the African mainland. The more species-rich Mediterranean and Macaronesian radiation in Liparthrum occurred later in the Oligocene, most likely prior to the origin of the Atlantic islands.