Dolichoderus formosus

Dolichoderus formosus occurs in two distinct regions, one in south-western Western Australia, the other in south-central coastal South Australia. It is found in mallee and scrub habitats and nests under rocks.

Identification
Pale markings absent from lower margin of the eyes; head dark brown to black and similar in colour to gaster; sculpturing pattern of head and pronotum, with large but shallow and closely spaced foveae; in dorsal view the pronotum with only weakly defined shoulders, with the area between the shoulders more strongly convex to flat; pronotum and propodeum lacking spines; dorsum of propodeum weakly and evenly convex, the length shorter (at most approximately the same length) than the posterior face, with a narrow carina separating the dorsal and posterior faces; posterior face of propodeum weakly concave, separated from the dorsal face by a distinct carina; mesosoma with erect hairs but few to no appresssed pubescence; gaster dark brown to black with little or no pubescence; tibiae with erect or suberect hairs.

Dolichoderus formosus is similar to Dolichoderus canopus, but is distinguishable by the large, shallow and closely spaced foveae on the dorsum of the head and pronotum, which are distinctly striate on the lateral pronotum. This species most closely resembles Dolichoderus nigricornis but can be distinguished by having the head colour similar to the gaster (dark brown to black) compared to the lighter coloured head (reddish to reddish-brown) and dark gaster (dark brown to black) in D. nigricornis, and in lacking appressed pubescence from the mesosoma and gaster.

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Nomenclature

 *  formosus. Dolichoderus (Hypoclinea) formosus Clark, 1930b: 265, fig. 15 (w.q.) AUSTRALIA. Senior synonym of occidentalis: Shattuck & Marsden, 2013: 119.
 * occidentalis. Dolichoderus (Hypoclinea) occidentalis Clark, 1930b: 268, fig. 12 (w.) AUSTRALIA. Junior synonym of formosus: Shattuck & Marsden, 2013: 119.

Description
Body colour varying from red to black with mandibles, antennae and legs varying from reddish-brown to brown. Sculpturing ranging from smooth and shiny to weakly matte.

Measurements (n=5). CI 78–84; EI 28–32; EL 0.25–0.27; HL 1.05–1.15; HW 0.84–0.95; ML 1.43–1.60; MTL 0.76–0.86; PronI 70.85–76.37; PronW 0.59–0.70; SI 112–123; SL 1.02–1.11.

Additional References

 * Shattuck, S.O. & Marsden, S. 2013. Australian species of the ant genus Dolichoderus (Hymenoptera: Formicidae). Zootaxa 3716, 101–143 (doi 10.11646/zootaxa.3716.2.1).