Rhytidoponera taurus

Identification
Large ants that, like Rhytidoponera mayri, have workers that are easily distinguished from other Rhytidoponera workers in the SWBP by their occipital cornicles.

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Nomenclature

 *  taurus. Ectatomma (Rhytidoponera) cornutum subsp. taurus Forel, 1910b: 12 (w.) AUSTRALIA. Forel, 1915b: 12 (m.). Combination in Rhytidoponera: Emery, 1911d: 38. Raised to species and senior synonym of brevior, fusciventris: Clark, 1936: 25.
 * fusciventris. Rhytidoponera cornuta var. fusciventris Stitz, 1911a: 352 (w.) AUSTRALIA. Junior synonym of taurus: Clark, 1936: 25.
 * brevior. Rhytidoponera cerastes var. brevior Crawley, 1925b: 586 (w.m.) AUSTRALIA. Junior synonym of taurus: Clark, 1936: 25.

Worker
Crawley (1925) - Length 10.6 mm.

Red-brown, legs and apices of funiculi somewlhat paler.

Larger than the preceding in most specimens, and lighter in colour. Differs also as follows: —mandibles with minute teeth; anterior border of clypeus more broadly rounded; head as broad as long, not narrowing so much at occiput; frontal carinae wider behind; scapes slightly longer, passing the occipital border by one-half their length. Horns like those of cornuta, shorter than in cerastes, the space between not evenly excavate, but widely angular, and the points turn more outwards, but in profile the points do not curve forwards as in cornuta.

Petiole higher and thinner than in cerastes, descending rapidly behind, and concave in front, so as to appear to lean forward; from above it is longer and narrower. Dorsum of thorax similar. The constriction between postpetiole and gaster is more pronounced. The sculpture is coarser, the head and thorax being entirely reticulate-punctate, the punctures not well-defined and circular as in the type; there is no ground-sculpture. The space between the horns has irregular transverse ridges and punctures. The declivity of the epinotum, which is less defined, is transversely rugose.

The postpetiole is finely concentrically striate with scattered points, the first segment of gaster has longitudinal strire curving inwards at the apex of the segment and scattered points. The legs are covered with short stiff erect hairs and are more coarsely sculptured.

Male
Crawley (1925) - Length 9.2 mm.

Russet-brown; petiole, gaster, coxre, trochanters, and femora, lighter; apical segments of gaster edged with golden-yellow. Wings yellowish brown, iridescent, the nervures brown. Abundantly provided with fine erect yellowish pilosity, including the legs and antennae. Pubescence almost nil,. except on funiculi, tibiae, and tarsi.

Mandibles as convex in centre, the anterior border depressed. Frontal carinae short, almost parallel. Eyes prominent, placed in centre of the sides, and equal in length to one-half the side of the head. Head as long as broad, as broad in front as behind, the occiput rounded. Antennae 13-jointed, the scape equals the first and second joints together, all joints very long, diminishing in length to the apical.

Pronotum high and arched, the Mayrian furrows visible but faint, the scutellum very prominent, longitudinally incised. Epinotum evenly convex, the declivity slightly flattened.

Petiole from above nearly twice as long as broad, slightly broader behind, in front there is a small projection on each side. In profile it rises gradually to its highest point, which is one-third from the posterior border, but it is only about one-sixth higher than in front.

Postpetiole narrow in front, longer and narrower than the first segment of gaster, which is broader than long and only slightly broader behind. Legs and antennae long and slender.

Shining; mandibles finely striate with a few minute punctures; scapes superficially striate. Whole of head and thorax closely and coarsely rugose-punctate, more densely than in the worker; the declivity of epinotum transversely rugose. Legs almost entirely smooth and shining. Upper surface of petiole transversely ridged, the sides reticulate-rugose. Postpetiole transversely striate above, the apical border and sides reticulate; the first two segments of gaster finely and evenly longitudinally striate.

References based on Global Ant Biodiversity Informatics

 * Fisher J., L. Beames, B. J. Rangers, N. N. Rangers, J. Majer, and B. Heterick. 2014. Using ants to monitor changes within and surrounding the endangered Monsoon Vine Thickets of the tropical Dampier Peninsula, north Western Australia. Forest Ecology and Management 318: 7890.
 * Heterick B. E., B. Durrant, and N. R. Gunawardene. 2010. The ant fauna of the Pilbara Bioregion, Western Australia. Records of the Western Australian Museum, Supplement 78: 157-167.
 * Taylor R. W. 1987. A checklist of the ants of Australia, New Caledonia and New Zealand (Hymenoptera: Formicidae). CSIRO (Commonwealth Scientific and Industrial Research Organization) Division of Entomology Report 41: 1-92.
 * Taylor R. W., and D. R. Brown. 1985. Formicoidea. Zoological Catalogue of Australia 2: 1-149.
 * Wheeler W. M. 1915. Hymenoptera. [In Scientific notes on an expedition into the north-western regions of South Australia.]. Transactions of the Royal Society of South Australia 39:805-823.