1ST KARYOTYPIC DATA ON A CUPEDID BEETLE (COLEOPTERA, ARCHOSTEMATA) SHOWING ACHIASMATIC MEIOSIS

The chromosomes of a species of Cupedidae, Distocupes varians (Lea) we re studied for the first time. The male diploid chromosome number of t he species is 2n = 19 and the male sex chromosome system is of the XO type. The presence of 9 pairs of autosomes agrees with the hypothesis that suggests that this number is the ancestral condition for the whol e Order Coleoptera. On the other hand the analysis of the spermatogene sis reveals an achiasmatic meiosis pattern. The occurrence of this kin d of meiosis in Cupedidae (never recorded in Polyphaga, but present in some groups of Adephaga) is in agreement with hypotheses that relate Archostemata with Adephaga.