CLADISTIC AND BIOGEOGRAPHIC ANALYSES OF THE WEEVIL GENUS LISTRODERES SCHOENHERR (COLEOPTERA: CURCULIONIDAE).

Abstract- The weevil genus Listroderes Schoenherr is a monophyletic group defined by the body vestiture consisting of subcircular to suboval scales, and comprises 35 species endemic to southern South America. A cladistic analysis of the genus was carried out using 44 characters from external morphology, body vestiture, and male and female genitalia. The curvipes (three species), nodifer (five species) and robustus (four species) species groups and the 23 species of the costirostris species group were considered terminal taxa. Apomorphic states were identified using the genus Hyperoides Marshall as outgroup. The analysis yielded 122 equally parsimonious cladograms, each with 89 steps and a consistency index of 0.42; a successive weighting procedure resulted in nine cladograms (consistency index of 0.69 and retention index of 0.85). In the general consensus cladogram, nodifer-robustus and curvipes-costirostris are two pairs of sister species groups. The costirostris group comprises the subgroups foveatus, angusticeps, costirostris, delaiguei, bimaculatus and elegans, in phylogenetic order. A distributional analysis of the species of Listroderes led to identification of four areas of endemism, namely central Chile, sub-Antarctic, central Argentina and Chaco. A vicariance biogeographic analysis of these areas, based on area cladograms of Listroderes, Hyperoides, Naupactus taeniatulus species group (Coleoptera: Curculionidae), and Lucilia generic group (Asteraceae) was carried out applying the three-area statements technique. According to the general area cladogram the sequence of area-fragmentation is as follows: (central Chile (sub-Antarctic (central Argentina, Chaco))). This sequence is congruent with the history hypothesized for the region, where the uplift of the Andes (Oligocene-Pliocene) led to a progressive aridification, replacing the ancient subtropical forest by open-country environments.