On the Systematic Position of the Genus Euphyllobiomorphus: an Adelognathous Weevil with Cylindrical Rostrum (Coleoptera, Curculionidae)

Abstract

Euphyi’lobiomorphus is unique in its cylindrical rostrum, exposed maxillae and thin mandibles as in the Phanerognatha like an anthonomine weevil, whereas the mandibles have deciduous process and the larval antennae are cushionshaped as in the .Adelognatha. Without regard to the phanerognathous features, this genus conforms to the taxon including Phyllobiini, Polydrusini and Cyphicerini of the Adelognatha principally on the structures of the metendosternite, ovipositor, aedeagus, maxillae and elytra. In this taxon, Euphyllobiomorphus belongs to Phyllobiini- Polydrusini group by the connate claws and exposed maxillae in the adult and by the larval spiracles unicameral on thorax and bicameral on abdomen. In consideration of these characteristics and character polarities, stepwise change in Euphyllobiomorphus-Phyllobiini-Polydrusini-Cyphicerini lineage from the phanerognathous ancestor is inferred, and Euphyllobiomorphus is considered to be the first branch of this lineage before the loss of drilling function in the head and rostrum.