RELATIONSHIPS AMONG THE MAJOR SUBGROUPS OF BRACHYCERA (DIPTERA) - A CRITICAL-REVIEW

Six major subgroups of the Brachycera are recognized under the names S tratiomyomorpha, Vermileonomorpha new infraorder, Tabanomorpha, Nemest rinoidea, Pleroneura, and Eremoneura. Recent suggestions regarding the possible sister-group of the Brachycera are reviewed, and all found t o be inadequately supported. Characters used to support possible relat ionships between the major subgroups (i.e. possible synapomorphies) ar e reviewed with respect to morphological interpretation and polarity. On the basis of this analysis, five partly conflicting possible groupi ngs are discussed: (1) all other Brachycera as the sister-group of the Stratiomyomorpha; (2) Muscomorpha sensu Woodley (Nemestrinoidea + Het erodactyla); (3) inclusion of Nemestrinoidea in Tabanomorpha; (4) Hete rodactyla sensu Lameere (Pleroneura + Eremoneura); and (5) an asilotab aniform group (Vermileonomorpha + Tabanomorpha + Nemestrinoidea + Pler oneura). Resolution of conflicts among these possible groupings will r equire critical morphological studies of the phallic complex and embry ological studies of groups of Brachycera other than Cyclorrhapha. Beca use of present uncertainties, it is recommended that authors consider alternatives rather than rely on a single preferred concept of phyloge ny at this time. Autapomorphies of the major subgroups are discussed i n an appendix.