Phylogenetic analysis of Myxophaga (Coleoptera) using larval characters

A phylogenetic parsimony analysis of fifty-four larval characters of Myxoph aga (excluding Lepiceridae) resulted in two minimal length cladograms. The monophyly of Torridincolidae, Hydroscaphidae and Microsporidae is supported by several autapomorphies: miniaturization, flattened body with laterally extended tergites, broadened head, scale-like surface structures, broad ten torial bridge, disc-shaped labral sensilla, spiracular gills and pupation i n the last larval exuviae. Hydroscaphidae are the sister group of Microspor idae. Larvae of both families are characterized by semi-entognathous mouthp arts, tergites with posterior rows of lancet-shaped setae, claws with flatt ened basal spines and balloon-shaped spiracular gills. The monophyly of all families is supported by autapomorphies. Torridincolidae excluding Delevea is defined as a monophylum by four derived character states: body ovoid, t horax semicircular and as long as abdomen, labral sensilla fused and abdomi nal sternite IX distinctly reduced and triangular. The monophyly of Torridi ncolinae (sensu Endrody-Younga, 1997b) is supported by two autapomorphies. The proposed branching pattern suggests that the early representatives of M yxophaga (excluding Lepiceridae) were living in aquatic conditions with a p reference for hygropetric habitats. The tendency to live on rocks in runnin g water and miniaturization have played an important role in myxophagan evo lution.