PHYLOGENY OF THE BRACHYURA WITH PARTICULAR REFERENCE TO THE PODOTREMATA - EVIDENCE FROM A REVIEW OF SPERMATOZOAL ULTRASTRUCTURE (CRUSTACEA,DECAPODA)

Parsimony analysis, whether using only spermatozoal characters or sper matozoal and non-spermatozoal characters, suggests that: (i) the Brach yura is a monophyletic taxon relative to the outgroup, three paguroids ; (ii) the Podotremata is a monophyletic taxon and the sister-group of the heterotreme-thoracotreme assemblage; (iii) within the Podotremata , the Dromiidae appears paraphyletic as its clade includes Paradynomen e; (iv) the Homolidae is a monophyletic family; (v) the Raninoidea and Cyclodorippoidea are sister groups within a monophyletic (unnamed) cl ade; (vi) Latreillia sp. forms a polytomy with Homolidae + Raninoidea- Cyclodorippoidea; and (vii) within the heterotreme-thoracotreme assemb lage, the Thoracotremata is a monophyletic taxon but the Heterotremata s. strict. is a paraphyletic grouping. Analyses based on sperm data a lone differ from the combined data in not including the Homolidae in t he Archaeobrachyura (Homolidae + Raninoidea-Cyclodorippoidea), thus th e Dromiidae-Paradynomene + Homolidae + Latreillia form a polytomous cl ade which is the sister-group of the Raninoidea + Cyclodorippoidea. Sp ermatozoal data also give majids the most basal position in the Hetero tremata whereas for the combined data Neodorippe (a shell carrier) app ears the least modified member of the heterotreme-thoracotreme assembl age. These findings are viewed in the perspective of other, notably mo lecular, studies. Spermatozoal synapomorphies are listed and illustrat ed.