Kempfidris
Kempfidris is a Neotropical genus of ants in the subfamily Myrmicinae containing the single species Kempfidris inusualis. Known from Brazil, Ecuador and Venezuela, the species was originally described as Monomorium inusuale in 2007, but was reclassified as the type species for the new genus Kempfidris in 2014. The species is only known from workers and almost nothing is known about their natural history.
Description
The genus was described in 2014 based on the workers of a single species, K. inusualis, originally described by and provisionally placed in Monomorium awaiting a better understanding of the internal relationships in Myrmicinae. Kempfidris has a series of distinctive morphological characters including the mandibular configuration, vestibulate propodeal spiracle, propodeal carinae, and cylindrical micro-pegs on the posteromedian portion of abdominal tergum VI and anteromedian portion of abdominal tergum VII. This last trait appears to be autapomorphic for the genus. Queens and males are unknown.The most outstanding feature of Kempfidris is the series of minute, hair-bearing tubercles or cylindrical pegs on the abdominal apex. Most are concentrated on the anteromedian portion of the pygidium and some on the posteromedian portion of abdominal tergite VI, a position that would coincide with the position of the pygidial gland, which opens between abdominal tergites VI and VII. The structure of the micropegs with their associated hairs also hints at some sort of glandular function, or possibly a mechano-reception function during stinging, but a more convincing explanation will only be possible after a histological study. Whatever the function of these tubercles, they appear to be an autapomorphic structure, absent in other Myrmicinae and probably in other ants as well. In ants, the most structurally similar cuticular projections can be found throughout most of the body of some species in the formicine genus Echinopla, except on the pygidium, and additionally on the gastral apex of an undescribed species of Strumigenys. Given that these aforementioned taxa are not closely related to Kempfidris, their structures are probably not homologous, but perhaps convergent evolution could be considered, especially in the case of the dacetine ant. Other specialized pygidial structures found in ants are the denticles or spines of Cerapachyinae and the large, upward-curving teeth in Pachycondyla crassinoda workers, but their position and form are very different. Most members of the solenopsidine group are smooth, with little sculpturing, but this species presents a moderate amount of sculpturing on the head, mesosoma, petiole and postpetiole.