Cytogenetic aspects of the phylogeny of the genus Chironomus Meigen (Diptera, Chironomidae)

Shobanov, N. A.; Zotov, S. D.

Based on the comparative integrated analysis of the banding pattern of the chromosome arms A, E and F, a phylogram for 94 species of the genus Chironomus has been created. The trend of the inversion polymorphism of the examined arms is shown to be associated with cytocomplexes formation. Arguments in favor of the ancestral nature of the thummi cytocomplex in the genus Chironomus are presented. The evolution of larval forms from the salinarius to the plumosus form is hypothesized; species of the fluviatilis, semireductus and reductus forms are represented only by terminal branches originating from the thummi (fluviatilis) and plumosus (semireductus and reductus) forms. It is assumed that the ancestor of Ch. piger and Ch. riparius belongs to the pseudothummi cytocomplex, and the combination of the chromosome arms characteristic of these species (AB CD EF G) is a recurrence having secondarily originated from the AE BF CD G combination. Species of the riihimakiensis and pilicornis groups are not directly linked in the phylogram which presumes their remote affinity.