The phylogeny of cockroach families: a cladistic appraisal of morpho-anatomical data

Abstract

Seventy-two morpho-anatomical characters were examined in 221 genera belonging to the families Blattidae, Polyphagidae, Blattellidae, and Blaberidae. They were cladistically analyzed and polarized using two mantids and two termites. As no autapomorphies of the family Blattellidae were found, the constituent subfamilies were used as terminal taxa together with other families. Three trees were found (CI = 0.81 and RI = 0.88, without autapomorphies) that differed only by the position of Nyctiborinae relative to Blattellinae and Ectobiinae. The strict consensus tree was [Blattidae [Polyphagidae [Anaplectinae [[Pseudophyllodromiidae, Blaberidae] [Nyctiborinae, Blattellinae, Ectobiinae]]]]]. The main discrepancies with McKittrick's tree were the monophyly of Polyphagidae (instead of paraphyly) and that the Blaberidae is the sister-group of Pseudophyllodromiinae (instead of the sister-group of Blattellinae, Ectobiinae, and Nyctiborinae). These results made it necessary to elevate the Anaplectinae and Pseudophyllodromiinae to familial status, and to give a new sense to the family Blattellidae, which includes only the subfamilies Blattellinae, Ectobiinae, and Nyctiborinae. This phylogeny was used to test current evolutionary hypotheses concerning sociality and reproductive behaviour; many traits were assumed to be ancestral to all cockroaches (protozoan symbionts and familial life habits) or preadaptive (progressing from advanced oviparity in Blattellidae to ovoviviparity in Blaberidae) that must actually be considered homoplasic.