We used mitochondrial (12s, 16s) and nuclear (18s, 28s) ribosomal gene sequences to derive a phylogeny of the Eumastacoidea, with the aims of a) clarifying the position of the Proscopiidae with respect to the Eumastacoidea b) testing the phylogenetic hypothesis and classification advanced by Descamps 1973b for the Eumastacoidea, and c) deriving a time scale for the phylogeny based on molecular clock calculations. Four different analysis methods were employed: maximum parsimony, neighborjoining assuming minimum evolution, maximum likelihood and Bayesian analysis. The genes were analysed separately and after concatenation. The sample included 6 of the 7 families and 12 of the 31 subfamilies of the Eumastacoidea, and three proscopiids. We included tetrigoids (as outgroup) and tanaoceroids and trigonopterygoids to provide polarity.
No analysis supported placing the Proscopiidae within any of the existing branches of the Eumastacoidea. Some placed the two taxa as sistergroups within a Eumastacoidea s. lat., and some indicated that they are separate superfamilies. We cannot distinguish between these two possibilities with the present data.
Within the Eumastacoidea s.str. all of the groupings of subfamilies (i.e., families) proposed by Descamps were well-supported. Higher nodes of the phylogeny were in general only weakly supported. Descamps' suprafamilial groupings appeared in some but not all analyses. Of these groupings, the Cryptophalli (=Chorotypidae plus Episactidae) were not well supported, the Stenophalli (Eumastacidae plus Morabidae) were reasonably well supported, while the Disclerophalli (=Thericleidae plus Euschmidtiidae) were strongly supported, and additionally the Gomphomastacinae were associated with it. (The Euphalli, containing only the Indian family Mastacideidae, were not included in the analysis.)
The sequence data did not allow the assumption of a molecular clock, and for this reason the nodes of the phylogeny could not be dated.