Morphological and molecular evidence in the phylogenetic reconstruction of large beetle groups: Examples from the weevils

ADRIANA E. MARVALDI

Congreso; IX Reunión Argentina de Cladística y Biogeografía; 2010

The Weevils (Coleoptera: Curculionoidea), together with their sister group Chrysomeloidea, constitute an enormous clade of phytophagous beetles. The study of the phylogenetic relationships of the order Coleoptera, based on morphology and molecules, is a major goal of an international collaborative research: the Beetle Tree of Life project. Being so extraordinarily speciose, the phylogenetic systematics of weevils remains challenging, but advances are made thanks to the use of multiple sources of evidence. These come from weevil morphology (of adult and immature stages) and from various molecular markers that are now available for a wider taxon sampling. The sequence data come from ribosomal RNA (nuclear 18S and 28S, mitochondrial 16S) and protein-coding genes (nuclear Arginine kinase, mitochondrial COI). In the present contribution I report the progress made towards a predictive phylogenetic hypothesis for the weevils, based on a taxon sampling of more than 170 species representative of all families and subfamilies in current classifications.  In this study, the alignment of the RNA datasets (18S, 28S, 16S) was performed according to structure information, a method that uses a biological criterion (covariation) for assigning positional nucleotide homology. The annotated alignment of the sequences of the weevils, and several outgroups, provides improved rRNA structure models and can be useful as template for further phylogenetic reconstruction in beetles. The results of the parsimony analysis of the combined molecular data corroborate some important clades also suggested by recent hypotheses based on morphology (e.g., families), and also help resolving some controversial nodes (e. g., the placement of the platypodines) and discovering new ones.