A MORPHOMETRIC APPROACH TO THE TAXONOMY OF THE GENUS CERAMIDA (COLEOPTERA: SCARABAEOIDEA: MELOLONTHIDAE)

Abstract

AbstractThe taxonomy of the genus Ceramida Baraud, 1987, some species of which are severe pests, is considered difficult because of a lack of reliable diagnostic characters. We propose a new approach to the taxonomy of this genus by studying the efficacy of morphometric characters for species discrimination employing multivariate analysis. All members of the genus were included in the analysis. The seven morphometric characters considered were all found to be diagnostic at me species level: width of clypeus at base and at mid-length, and length of clypeus, full body, antennal club and stem, and apical segment of maxillary palp. The most informative character is the length of the antennal club relative to body size. This character divides the genus into three morphological groups. The ratios traditionally employed in the taxonomy of this genus cannot be used as discrete characters because there are no gaps in their range of variation. Our discriminant analysis produced several classification functions that serve as a new taxonomic tool to distinguish between morphologically similar species. Eleven species are recognized within the genus and eight new synonymies are proposed.