Phrynoponera Wheeler

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 : 127-129

Phrynoponera Wheeler

Fig. 23

Phrynoponera Wheeler, W.M., 1920: 52 (as genus). Type-species: Bothroponera gabonensis André, 1892: 50 ; by original designation.

Phrynoponera is a small genus (five described species) restricted to the African tropics. Its sister group is unresolved and very little is known about its habits.

Diagnosis. Diagnostic morphological apomorphies of Phrynoponera workers include their posterodorsal propodeal spines and their squamiform, sweeping five-spined petiolar node. Propodeal spines or teeth also occur in Streblognathus , Pseudoneoponera bispinosa , and some species of Anochetus and Platythyrea , but these taxa all lack the unusual petiolar node of Phrynoponera , which is autapomorphic within Formicidae . Superficially, Phrynoponera most resembles Bothroponera (s.s.) and Pseudoneoponera , but it is readily separated from these genera by the combination of propodeal spines, unusual petiole structure, and weak gastral constriction. Bolton & Fisher (2008b) discuss additional diagnostic characters of the petiolar sternite and prora of Phrynoponera .

Synoptic description. Worker. Medium to large (TL 5–12 mm; Bolton & Fisher, 2008b) robust ants with the standard characters of Ponerini . Mandibles subtriangular, with a basal groove. Frontal lobes large. Eyes moderately large and placed anterior of head midline. Metanotal groove obsolete or vestigial dorsally. Propodeum broad dorsally, with a pair of sharp teeth on the posterodorsal margin. Propodeal spiracle a short slit. Metatibial spur formula (1s, 1p). Petiole squamiform, the scale curving posteriorly and armed with five sharp teeth posterodorsally. Gaster without a distinct girdling constriction between pre- and postsclerites of A4. Head and body coarsely sculptured, with abundant pilosity and no pubescence. Color variable. See Bolton & Fisher (2008b) for a more detailed description of these and other characters.

Queen. Similar to workers but alate, with three ocelli on the head and a transverse sulcus on the mesopleuron ( Bolton & Fisher, 2008b).

Male. See description in Bolton & Fisher (2008b).

Larva. Not described.

Geographic distribution. Phrynoponera occurs in the forests of tropical Africa, with most species restricted to central Africa. P. gabonensis has the widest range, occurring from Ivory Coast to Kenya and from Sudan to Angola. P. pulchella , likely the sister to the rest of the genus, is known only from Kenya ( Bolton & Fisher, 2008b).

Ecology and behavior. Bolton & Fisher (2008b) summarized what little is known about the ecology and behavior of Phrynoponera . These ants inhabit forests and nest in rotten wood, soil ( Bolton & Fisher, 2008b), or in termite mounds (Déjean et al., 1996, 1997). They are infrequently collected in the leaf litter ( Belshaw & Bolton, 1994) and are apparently generalist predators (Déjean et al., 1999). The unusual petiole structure of Phrynoponera presumably evolved for defensive purposes, but the identity of the predator(s) involved is unknown. Many specimens examined by Wheeler (1922b) were extracted from the stomachs of toads.

Phylogenetic and taxonomic considerations. Wheeler (1920, 1922b) erected Phrynoponera to house Bothroponera gabonensis André and several new species. He believed that these taxa were distinct from Bothroponera (including Pseudoneoponera , which we consider to be a separate genus) based on a number of characters. He noted that Pseudoneoponera bispinosa and Ps. rufipes each have a morphological character that is reminiscent of the condition in Phrynoponera (propodeal spines in the former and a denticulate squamiform petiole in the latter), but believed that these characters were independently derived. In their recent revision of Phrynoponera, Bolton & Fisher (2008b) agreed with this assessment, and noted an additional morphological similarity between Phrynoponera and both Asphinctopone and Brachyponera , a similarity that they believed was also convergently derived. Brown (1973) provisionally synonymized Phrynoponera with Pachycondyla , but Bolton (1994) revived it to full genus status.

We continue to treat Phrynoponera as a distinct genus. Morphologically it is quite different from all other genera, with several autapomorphies in both sexes. Phrynoponera workers superficially resemble those of Bothroponera (s.s.) and Pseudoneoponera , as all three are characterized by a robust build, strong sculpturing, an obsolete metanotal groove, and a broad propodeal dorsum. On the other hand, all of these characters have evolved independently in other ponerines on multiple occasions, so they are not likely to be good phylogenetic markers. Schmidt's (2013) molecular phylogeny places Phrynoponera with strong support within the Odontomachus group, but does not resolve its sister group. Phrynoponera is certainly not closely related to Pachycondyla , but a sister relationship with either Bothroponera or Pseudoneoponera cannot be rejected at this time. Interestingly, the best supported sister group of Phrynoponera is Anochetus and Odontomachus , though it is difficult to identify any morphological synapomorphies linking these genera.

Figures

FIGURE 23. Worker caste of Phrynoponera gabonensis: lateral and dorsal view of body and full-face view of head (CASENT0178229, April Nobile and www.antweb.org); world distribution of Phrynoponera.