Probolomyrmex latalongus

This is by far the most widely distributed species of Probolomyrmex in Australia. It ranges across northern Australia from Barrow Island in the west to Cape York Peninsula in the east. It also occurs in a wide range of habitats, from rainforests on Cape York Peninsula to Eucalyptus woodland in the Top End of the Northern Territory (Andersen et al., 2006) to grasslands on Barrow Island, Western Australia. Most encounters have been from leaf litter samples but one collection involved pitfall traps while another was a queen from a flight intercept trap.

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; body small (HW < 0.33mm, ML < 0.65mm) and head narrow (CI < 66).

Probolomyrmex latalongus is similar to Probolomyrmex greavesi (from Australia) and Probolomyrmex vieti (from Thailand, Vietnam and Indonesia). It differs from both by its smaller size and from P. vieti by the anteriorly angular subpetiolar process (the process having an anterior tooth in P. vieti).

Key to Australian and Melanesian Probolomyrmex species

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Nomenclature

 *  latalongus. Probolomyrmex latalongus Shattuck, Gunawardene & Heterick, 2012: 44, figs. 3, 7 (w.) AUSTRALIA.

Description
Worker description. Body 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 weakly concave; posterior face of propodeum separated from sides by a sharp angle, the lamella being very weakly developed. Petiole including subpetiolar process slightly higher than long, in profile with relatively steep anterior face and straight 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 to concave. Abdominal segment III (gastral segment I) in profile relatively short, gently narrowed anteriad in the anterior 2/3; abdominal sternum III weakly and uniformly convex.

Measurements. Worker (n=9)—CI 62–65; DPetW 0.13–0.16; HL 0.46–0.51; HTL 0.25–0.30; HW 0.29–0.32; LPetI 88–98; ML 0.54–0.65; PetH 0.20–0.24; PetNL 0.19–0.22; PronW 0.22–0.25; SI 79–91; SL 0.24–0.28