Rhytidoponera cerastes

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Nomenclature

 *  cerastes. Rhytidoponera cerastes Crawley, 1925b: 584, fig. 1 (w.) AUSTRALIA. Wheeler, G.C. & Wheeler, J. 1964b: 448 (l.).

Worker
Length 9.5-10.5 mm. Head (base of mandibles to end of horns) 2.6 mm., widest point (at cheeks) 2.3 mm.

Head ilnd thorax dark red-brown, gaster, scapes, and legs darker, funiculi and tarsi palest, the former becoming lighter towards the apex.

Head and thorax almost glabrous, except for long hairs on clypeus and underneath head, and on the apical segments of gaster. Scapes with a few scattered and very short hairs; funiculi pubescent. Underside of tibiae with rows of stiff bristles.

Mandibles large, the terminal border one-third longer than the basal, and entirely without teeth (in cornuta it is dentate), though slightly irregular, and in some specimens with an indication of a tooth lying under the apical. Clypeus Hat with a narrow central stria. Frontal carinae narrow rapidly behind where they are one-half as wide as in front. Eyes placed behind the middle of sides of head. Head (including the horns) longer than broad, broadest at cheeks, the sides narrowing gradually to the base of the horns where it is barely two-thirds as broad as in front. Seen from the front, the horns are triangular, as long as they are wide at base, the point slightly turned outwards. They are longer than in cornuta, Em., and the spaDe between them is evenly excavate and deeper. In profile they are in the form of a pointed cone, the apex not turned outwards as in cornuta; there is an impression marking the line of the base of each horn.

Thorax in profile impressed at the pro-mesonotal suture and widely and shallowly emarginate at the junction of the meso- and epinotum (entirely unbroken in cornuta). Pronotum wider behind than in front; laterally there is a wide and oblique impression. The inferior angles end in a small tooth. Epinotum evenly rounded, the declivity “small and slightly flattened. Petiole in profile higher in front, where it is almost straight, the top evenly sloping. From above it is barely longer than wide, and twice as wide behind as in front. Down the centre runs a deep narrow impression. Beneath anteriorly is a small spine perpendicular to the segment.

Postpetiole and first segment of gaster equal in length.

Shining; mandibles finely striate with small scattered points.

Upper surface of head, including frontal carinae and clypeus, coarsely reticulate-punctate. The impressions at the bases of the horns are finely reticulate only, the space between them smooth with a few shallow punctures; the back of the horns and the occipital border smooth and shining. Sides of head with large shallow punctures widely disposed, the spaces between finely reticulate. Scapes longitudinally striate.

Entire thorax with a fine ground-reticulation and in addition covered with circular punctures connected by coarse reticulations. Down the centre of the pronotum is a narrow strip finely and transversely striate only. The lateral impressions of the pronotum are extremely finely reticulate only. The petiole is coarsely rugose-punctate in front and on the sides, but behind and along the central impression transversely striate. Meso-epinotal emargination finely transversely striate, the declivity coarsely transversely striate. Postpetiole and first segment of gaster very finely transversely striate with scattered points, the remaining segments finely reticulate only.