<i>Adetomyrma</i> , an enigmatic new ant genus from Madagascar (Hymenoptera: Formicidae), and its implications for ant phylogeny

Abstract. Adetomyrma venatrix , representing a new genus and species of ant, is described from a single collection of twenty‐one workers from Zombitse Forest, in western Madagascar. Remarkable features of its morphology include: (i) absence of a petiole in dorsal view (abdominal tergum 3 lacking a dorsally differentiated pretergite), (ii) gaster large and expanded posteriorly, all terga and sterna unfused and without constrictions, (iii) absence of eyes, and (iv) presence of a very large sting (larger, in relation to body size, than that of any other known ant). Adetomyrma does not possess any of the derived features heretofore said to characterize the existing ant subfamilies. Morphological evidence suggests, however, that it is cladistically a member of the ponerine tribe Amblyoponini despite the absence of apomorphic abdominal characters (tergosternal fusion of abdominal segments 3 and 4) seen in all other Ponerinae and in the more inclusive ‘poneroid group’ of subfamilies. Whether Adetomyrma shows primitive absence of such characters or secondary reversal to an unfused state has important implications for the higher phylogeny of the ants. There is insufficient evidence to choose decisively between these two alternatives, but in either case the monophyly of the ant subfamily Ponerinae becomes doubtful.