Abstract

Simóes, M.G.; A.C. Marques; L.H. Mello & L.E. Anelli. Phylogenetic analysis of the genera of the extinct family Megadesmidae (Bivalvia, Anomalodesmata), with remarks on its paleoecology and taxonomy. J. Comp. Biol. 2(2):75-90. Toe analysis of 14 out of the 22 genera aruibuted to the family Megadesmidae from the Carboniferous/ Permian was carried out with dadistic methodology. A simple parsimony analysis resulted in a strict consensus tree corroborating the monophyly of the family. A second analysis, using successive weighting, resulted in a strict consensus tree in which the Grammysiidae could be hypothesized as a sister group of the monophyleric Megadesmidae. This analysis suggests three disrinct monophyletic groups for Megadesmidae: the Cuwperesia + Runnegariel/a group; the "Paraná Basin" group (perhaps a sister group of Cowperesia + Runnegariella), and the "Australian group". Based on a semi-stril1: consensus tree we define herein rwo new subfamilies: Megadesmiríae and Plesiocyprinellinae subfam.n .. The new genus and species of the "Paraná Basin group" Itatamba gen.n. and Itattunba paraima sp.n. are described for a population of Ciuterel/a gratiosa, which resulted to be merophyleric. The evolurion and hypotheses on paleoecology of the group are presented and discussed.