Probolomyrmex greavesi

Probolomyrmex greavesi has been found in forested sites ranging from a non-native pine plantation through dry sclerophyll and into wet sclerophyll. It is known to nest in soil under rocks. It is one of the rarer Australian ants having been collected only a handful of times.

Identification
Petiolar node relatively short and broad and with the anterior and dorsal faces separated by a convexity; subpetiolar process forming a rounded 90° angle anteriorly and with the ventral margin straight; body large (HW > 0.35mm, ML > 0.65mm) and head broad (CI > 66).

Probolomyrmex greavesi is similar to Probolomyrmex latalongus (from Australia) and Probolomyrmex vieti (from Thailand, Vietnam and Indonesia). It differs from P. latalongus by its larger size (HW > 0.35mm and ML > 0.65mm vs. HW < 0.33mm and ML < 0.65mm in P. latalongus) and broader head (CI > 66 vs. CI < 66 in P. latalongus), and from P. vieti by the anteriorly angular and ventrally straight subpetiolar process (the process having an anterior tooth and concave ventral surface in P. vieti).

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Nomenclature

 *  greavesi. Probolomyrmex greavesi Taylor, 1965d: 358, figs. 2, 22-27 (w.q.m.) AUSTRALIA. See also: Shattuck, Gunawardene & Heterick, 2012: 43.

Description
Worker description. Body light ferruginous brown. Head in full-face view with weakly convex sides and very shallowly concave occipital border. Eye absent. Antenna relatively short. Dorsal outline of mesosoma straight; posterior margin of dorsum of propodeum in dorsal view moderately concave; posterior face of propodeum separated from sides by an angle, the lamella being absent. Petiole including subpetiolar process higher than long, in profile with relatively steep anterior face and convex posterior outline; posterodorsal margin of petiolar node in dorsal view very weakly concave; subpetiolar process developed; its anteroventral portion forming a rounded 90° angle; posteroventral portion of subpetiolar process forming a blunt tooth; ventral surface straight. Abdominal segment III (gastral segment I) in profile relatively short, gently narrowed anteriad in the anterior 2/3; abdominal sternum III weakly convex behind the midlength.

Measurements. Worker (n=5)—CI 67–69; DPetW 0.18–0.20; HL 0.52–0.58; HTL 0.32–0.37; HW 0.36–0.39; LPetI 80–88; ML 0.66–0.77; PetH 0.26–0.29; PetNL 0.22–0.25; PronW 0.26–0.28; SI 83–90; SL 0.31–0.35.

Additional References

 * Shattuck, S.O., Gunawardene, N.G. & Heterick, B. 2012. A revision of the ant genus Probolomyrmex (Hymenoptera: Formicidae: Proceratiinae) in Australia and Melanesia. Zootaxa 3444: 40–50.