The Neotropical Weevil Genus Entimus (Coleoptera: Curculionidae: Entiminae): Cladistics, Biogeography, And Modes Of Speciation

The weevil genus Entimus Germar is a monophyletic taxon, recognized by a combination of the following characters: large size (12–45 mm); presence of green, blue, and gold iridescent scales; antennae reaching base of prothorax, with second funicular article scarcely longer than first; widened frontal groove; pronotum as wide as long, granulate; elytra triangularly shaped; tibiae not crenulated or dentate within; scutellum protruding; and aedeagal apex slightly acute.

It includes seven species, which are endemic to the Neotropics, ranging from Mesoamerica to northeastern Argentina. A cladistic analysis was carried out using 16 characters from external morphology, body vestiture, and male genitalia. The analysis yielded four equally parsimonious cladograms, each with 33 steps, a consistency index of 0.60, and a retention index of 0.53.

After successive weighting, a single cladogram resulted, with 105 steps, a consistency index of 0.89, and a retention index of 0.90. According to this cladogram, the species of Entimus follow the sequence: E. arrogans Pascoe, E. granulatus (Linnaeus), E. imperialis (Forster), E. fastuosus (Olivier), E. sastrei Viana (= E. formosus Viana, syn. nov.), E. nobilis (Olivier), and E. excelsus Viana. According to predictions based on phylogenetic and distributional information available, the most likely mode of speciation for four species of the genus is sympatric, whereas E. arrogans and E. granulatus have followed an allopatric mode of speciation, and E. sastrei has followed the centrifugal mode of speciation.