Cytotaxonomy, classification and phylogeny of African Carventinae (Heteroptera: aradidae)

Abstract

The southern African species of the Aradidae subfamily Carventinae are revised, resuhing in the recognition of 7 genera, 24 species and 10 subspecies (excluding the nominal ones). Of these, 4 genera, 18 species and 10 subspecies are described as new. A neotype is designated for Dundocoris natalensis. Keys to the genera and species are given. Scanning electron photomicrographs of the dorsal and ventral aspects and external genitalia are provided for all the species. The cytogenetics of the group are discussed and idiograrns, based on chromosome area measurements, and photomicrographs of meiotic stadia (mostly metaphase I and metaphase II) are presented for all but one species. The chromosome numbers of the species vary between 2n = 7XY1Y2 and 2n = 32XY and XY, X1X2Y and XY1Y2 sex chromosome systems occur. Muhiple sex chromosome systems that originated from autosome-sex chromosome fusions are described for the first time in the Heteroptera. A unique case where two homologous autosomes have fused with the X- and Y -chromosomes respectively, is reported. Karyotype evolution and the origin of the different chromosome numbers are discussed and hypotheses presented. Pseudoploidy, fusions and to a lesser extent fragmentation, have played the major role in the karyotype evolution of the Carventinae. The cytogenetics of the other subfamilies of the Aradidae are briefly discussed and illustrated. It is argued that the ancestral chromosome number for the Carventinae and Aradidae (and therefore also the Pentatomorpha) is 2n = 14XY. The morphological and cytogenetic data are integrated in the classification of the Carventinae and several of the subspecies are based on chromosome number differences. The homeostatic genetic species concept is proposed and its application to the Carventinae is discussed. Phylogenies for the genera and species are proposed. The text is accompanied by more than 540 figures and more than 60 tables.