New Oxycoryninae from Central and South America: phylogenetic and biogeographical implications (Coleoptera: Belidae)

Abstract

Abstract. Balanophorobius Anderson gen.n. and its type species, B. gamezi Anderson sp.n. (Coleoptera: Curculionoidea: Belidae) are described from the vicinity of Cerro de Oro in the Osa Peninsula of Costa Rica. Adults were reared from larvae collected in mid‐March in flowers of an unidentified species of root parasitic Balanophoraceae, possibly Helosis cayennensis (Sw.) Spreng. Balanophorobius is characterized by small (<3.5 mm) size, a loosely articulated antennal club, fine golden pilosity covering the entire cuticle, a sculptured pronotum, and the presence of distinct elytral striae with the intervals between the striae somewhat convex, but not carinate. In addition, a second species of the previously monotypic Alloxycorynus Voss, A. whiteheadi Anderson sp.n., from Cuzco Province in Peru, is described. Known only from a single male specimen, this species is distinguished by its uniform pale brown body colour, apically acuminate prosternal process, mesosternal process expanded between the middle coxae into a ventrally directed, flat, platelike form, and the front tibia having a simple apical tooth. No information is available on its host plant associations. A reassessment of the phylogenetic relationships of Belidae including character states from adults of Balanophorobius is consistent with recently published results. The genera Hydnorobius, Oxycorynus, Alloxycorynus and Balanophorobius constitute a monophyletic clade, sister to the Parallocorynus–Rhopalotria clade, united in aspects of structure and natural history. However, relationships among the former four genera are unresolved. If one considers a host shift to Balanophoraceae from Hydnoraceae, then an arrangement placing Alloxycorynus and Balanophorobius as sister taxa, sister to Oxycorynus, sister to Hydnorobius, is favoured. Features of A. whiteheadi affirm the validity of the previously monotypic Alloxycorynus through the shared presence of a ventrally directed prosternal process and the innermost elytral costa effaced throughout most of its length. The discovery of Balanophorobius in Costa Rica is the first record of angiosperm root parasite‐associated Oxycoryninae from outside of South America and suggests a greater geographical range for these taxa than previously recorded.