Dolichoderus nigricornis

Dolichoderus nigricornis is one of the more widespread species, occurring across much of southern Australia. It is known from dry sclerophyll and riparian woodlands where it forages on trees. Nests are in soil under rocks.

Identification
Head reddish to reddish-brown and lighter in colour than dark brown to black gaster; sculpturing pattern of head and pronotum, with large but shallow and closely spaced foveae compared to the indistinct sculpturing pattern of D. canopus; pale markings absent from lower margin of the eyes; pronotum and propodeum lacking spines; in dorsal view the pronotum with only weakly defined shoulders, with the area between the shoulders more strongly convex to flat; 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 both erect hairs and scattered appressed pubescence; gaster dark brown to black with scattered appressed pubescence; tibiae with erect or suberect hairs.

This species is most similar to Dolichoderus formosus but can be distinguished from D. formosus by having a head lighter in colour (reddish to reddish-brown) than the gaster (dark brown to black) compared to the similar coloured head and gaster (dark brown to black) in D. formosus, and in having scattered appressed pubescence on the mesosoma and gaster.

Identification Keys including this Taxon

 * Key to Australian Dolichoderus Species

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Nomenclature

 *  nigricornis. Dolichoderus (Hypoclinea) nigricornis Clark, 1930b: 264, fig. 14 (w.) AUSTRALIA.

Worker
Bright red. Eyes and gaster black, antennae and legs brownish black, mandibles and clypeus yellowish red.

Subopaque, gaster shining. Head coarsely and irregularly punctate.

Clypeus longitudinally striate, almost rugose. Pronotum rugose, but not coarsely so, with some large shallow punctures at the sides. Mesonotum and epinotum coarsely rugose. Gaster microscopically punctate.

Hair yellow, short and erect, abundant throughout, but a little longer and more numerous on the gaster. Pubescence not apparent.

Head one-sixth longer than broad, the occipital border feebly, the sides strongly convex. Frontal carinae slightly longer than their distance apart. Clypeus convex above, the anterior border convex, feebly indented in the middle. Eyes small and convex. Scapes extending beyond the occipital border by one-third of their length; first segment of the funiculus one-fifth longer than the second, third as long as the second. Mandibles furnished with twelve sharp teeth. Thorax twice as long as broad. Pronotum almost twice as broad as long, the anterior border feebly convex, the angles bluntly rounded, the dorsum concave longitudinally; in profile flat above, the anterior face short and abrupt, the angles produced outward and forward. Mesonotum convex above. Epinotum longer than broad, convex laterally, the posterior border straight; in profile strongly convex longitudinally, overhanging the declivity, the latter strongly concave, one-third shorter than the dorsum, the superior border sharply margined. Node almost three times as broad as long, feebly concave in front, strongly convex above and behind. Gaster longer than broad, concave in front below. Legs long and robust.

Shattuck and Marsden (2013) - The available specimens show minor variation in leg colour, which varies from yellowish-red to reddish-brown, but otherwise all material is similar.

Measurements (n=5). CI 79–89; EI 31–35; EL 0.26–0.29; HL 0.92–1.03; HW 0.78–0.90; ML 1.25–1.41; MTL 0.67–0.75; PronI 67.26–71.66; PronW 0.53–0.61; SI 107–122; SL 0.91–1.00.