Parvaponera, Schmidt & Shattuck, 2014

Schmidt, C. A. & Shattuck, S. O., 2014, The Higher Classification of the Ant Subfamily Ponerinae (Hymenoptera: Formicidae), with a Review of Ponerine Ecology and Behavior, Zootaxa 3817 (1), pp. 1-242 : 198-200

Parvaponera gen. nov.

Fig. 47

Type-species: Belonopelta darwinii Forel, 1893d: 460 ; by present designation.

Parvaponera is a small, rarely encountered genus known from 7 species and subspecies. It is widely distributed, being found in tropical Africa and Madagascar, Southeast Asia and the Australian region. Its biology is essentially unknown.

Etymology. This genus name is derived from the Latin parva , alluding to the generally small size of these ants, combined with “pone”, derived from the subfamily name Ponerinae .

Diagnosis. Workers of Parvaponera can be separated from other Ponerinae by the following combination of characters: eyes small (2-4 facets) or absent, mandibles short, without a basal pit or groove, propodeal spiracle generally elongate or slit-like (oval or nearly circular in a few species), ventral apex of the metatibia with one pectinate and one simple spur and subpetiolar process triangular and with an anterior fenestra and/or a pair of teeth. They are most likely to be confused with Centromyrmex , Hypoponera or Ponera . While both Centromyrmex and Parvaponera have reduced eyes, Parvaponera lacks pusher-setae on the tibiae as found in Centromyrmex (although they are present on the mesobasitarsus in some species of Parvaponera ) and has a much more complex subpetiolar process which possesses either an anterior fenestra or posteroventral teeth, both of which are lacking in Centromyrmex . While superficially similar to Hypoponera and Ponera , Parvaponera has a pair of spurs present on the metatibia while only a single spur is present in these genera.

Synoptic description. Worker. Small, slender ants with the standard characters of Ponerini . Mandibles triangular and lacking a basal groove or pit. Clypeus generally with a central tooth or short projection, absent in a few African species. Frontal lobes moderately small. Eyes small in size or absent, located fairly anterior on head. Mesopleuron lacking a transverse groove. Metanotal groove present or absent. Propodeum not narrowed dorsally. Propodeal spiracle generally elongate or slit-like (oval or nearly round in a few African species). A row of short traction setae present on mesobasitarsus in African species (apparently absent in Asian species). Metatibial spur formula (1s, 1p). Petiole squamiform. Prora conspicuous. Girdling constriction between pre- and postsclerites of A4 apparent. Pretergite of A4 without a stridulitrum. Head and body finely punctate and with a matte surface, with sparse pilosity and abundant pubescence. Color variable, testaceous to dark brown.

Queen. Similar to worker but slightly larger, alate and with the other caste differences typical for ponerines.

Male. Not described.

Larva. Not described.

Geographic distribution. This small genus shows a broad distribution range, with species occurring in tropical Africa, Madagascar, Southeast Asia, Australia and the Solomon Islands.

Ecology and behavior. P. darwinii is widespread throughout the Old World tropics and until recently was known only from the queen caste ( Terayama, 1990), which along with worker structure suggests a hypogeic lifestyle. Morgan et al. (2003) analyzed the Dufour’s gland secretions of P. darwinii (as “ P. indica ”).

Phylogenetic and taxonomic considerations. Unfortunately none of the species placed here were included in Schmidt’s (2013) molecular phylogeny of the Ponerinae and the current treatment is based on morphology. Because of this the sister relationships of Parvaponera within the Ponerinae are uncertain. It shares the presence of stout traction setae on the mesobasitarsi with Buniapone , Centromyrmex , Feroponera and Promyopias . The absence of compound eyes in workers is shared with Boloponera , Centromyrmex , Dolioponera , Feroponera , Iroponera and Promyopias . However, it is unlikely that these characters share a common origin and they are more likely the result of adaptation to a cryptic lifestyle. Perhaps most interestingly, the subpetiolar process shares characteristics with Ponera in that species of Parvaponera have either an anterior fenestra and/or a pair of posteroventral teeth. It will be interesting to learn if this similarity is the result of close relationship or as a result of convergent evolution, as appears to be the case with the mesobasitarsus and reduction in eye size.

Figures

FIGURE 47. Worker caste of Parvaponera darwinii: lateral and dorsal view of body and full-face view of head (CASENT0172437, April Nobile and www.antweb.org); world distribution of Parvaponera.