Ponerinae

Yoshimura, M. & Fisher, B. L., 2007, A revision of male ants of the Malagasy region (Hymenoptera: Formicidae): Key to subfamilies and treatment of the genera of Ponerinae., Zootaxa 1654, pp. 21-40 : 30

Diagnosis of male ants of the subfamily Ponerinae in The Malagasy region

Antenna filiform, consisting of 13 segments. Scape not reaching posterior margin of head. Oblique mesopleural furrow not reaching pronotum at its posteroventral corner. Scuto-scutellar suture usually longitudinally sculptured. Petiole attached to abdominal segment III ventrally, so that dorsal constriction between the two segments is distinct and deep. Abdominal segment III as large as segment IV. Apical portion of abdominal sternum IX not bi-spinose. Pygostyles well developed. Hind tibia with one or two spurs. Forewing with costa, subcosta, radius, radial sector, media, cubitus, and anal veins present, as are 2r-rs, 2rs-m, 1m-cu, and cu-a cross veins.

Remarks. Our key includes all seven ponerine genera recorded from the Malagasy region. Discussions of other groups in the key to subfamilies will appear in future publications. Ergatoid males are known from several genera (e.g. Hypoponera in Ponerinae , Technomyrmex in Dolichoderinae , and Cardiocondyla in Myrmicinae ) but were excluded from this subfamily key. Ergatoid males of ponerine ants are easily distinguished by having: (1) abdominal segment III as large as segment IV; and (2) a distinct constriction between abdominal segments III and IV.

The characters used in the subfamily key are diagnostic for taxa in the Malagasy region only and might not apply to ants collected elsewhere. As in previous studies (Smith, 1943; Yoshimura & Onoyama, 2002), bispinose abdominal sternum IX is commonly used to separate the Cerapachyinae from other subfamilies. Bolton(2003) mentions a single species, the Neotropical Pachycondyla crassinoda (Latreille , 1802), having this character in the subfamily Ponerinae . We use the character of abdominal sternum IX because it is diagnostic within the Malagasy region. No known character is universally applicable to separate the males of Ponerinae , Formicinae , and Dolichoderinae . In this key, the longitudinally sculptured scuto-scutellar suture and the presence of the 2rs-m cross vein on the forewing is used to separate Ponerinae from the other two subfamilies, Formicinae and Dolichoderinae .

A few exceptions, however, exist for these character states in the region. For example, the scuto-scutellar suture in Odontomachus coquereli is smooth and shiny, not longitudinally sculptured. The 2rs-m cross vein on the forewing, however, is clearly present in O. coquereli . Outside the region, species of Dolichoderus have 2rs-m as illustrated in Brown & Nutting (1950: figs. 18 and 19, as the genera Dolichoderus and Hypoclinea ). Some small species of Ponera have reduced venation (Brown & Nutting 1950). Bernard (1968) identified three dolichoderine genera - Dolichoderus , Liometopum , and Iridomyrmex - by the presence of 2rs-m ("two cubital cells"), and illustrated a forewing of the genus Formica with 2rs-m present (Bernard's figure 299).

Constriction between abdominal segments III and IV has often been used to separate Ponerinae from other subfamilies (Bernard, 1968; Collingwood, 1979; Wheeler & Wheeler, 1986; Czechowski et al, 2002). This state, represented by an exposed presclerite of the fourth segment, is also used to separate Ponerinae from Formicinae in male-based keys of Japanese ants (Yoshimura & Onoyama, 2002). Shattuck (1992) also suggests that dolichoderine males can be distinguished from ponerine males by an abdominal constriction. However, this character state is often unclear in several ponerine genera (e.g. Hypoponera , a part of Pachycondyla ), including Malagasy species of these genera, and is not used in this key.

We use several regional characters to separate these three subfamilies (i.e. Ponerinae , Formicinae , and Dolichoderinae ). All of the species in the subfamily Formicinae examined in this study have long antennal scapes, while those of the species in the subfamily Ponerinae are short. This difference between Ponerinae and Formicinae seems akin to that seen in European ants (Bernard, 1968). This is likely a useful character for distinguishing between the two subfamilies, but both types of scapes are found in dolichoderine genera.

Reduction in overall size of the mandible is used by Kutter (1977) to separate Ponerinae from Formicinae and Dolichoderinae . It is potentially useful in a region where only species of the tribe Ponerini are distributed. A very short clypeus, a ponerine character used by Bernard (1968), can be used for some of the genera in the tribe Ponerini .