On the Affinities and Systematic Position of Lachnaeus Schoenherr and Rhinocyllus Germar in the Tribe Lixini (Coleoptera: Curculionidae: Lixinae) Based on the Morphological Characters of the Immature Stages.

Mature larvae and pupae of Lachnaeus crinitus Schoenherr, 1826 and Rhinocyllus alpinus Gültekin, Diotti and Caldara, 2019 and pupae of R. conicus (Frölich, 1792), belonging to the Lixini (Curculionidae: Lixinae), are morphologically described for the first time. They possess all the characters considered distinctive in the immature stages of this tribe and are distinguishable from all the related genera by a combination of some characters (e.g., presence of endocarina, shape of premental sclerite; the number of pds on the abdominal segments; size and presence of urogomphi). It is emphasized that the controversial tribe Rhinocyllini is not supported by the characters of the larvae and pupae of Rhinocyllus and that the two subgenera of this genus, Rhinocyllus s. str. and Rhinolarinus, are separable from each other not only by characters of the adult but also distinctive characters of the larvae and pupae. These results confirm that the morphology of the immature stages, which is usually overlooked, can be very important for the purpose of identifying new characters that are useful for clarifying taxonomical and phylogenetic complex situations based only on the study of the imagoes.