Nesomyrmex koebergensis

Found while excavating a Camponotus nest.

Identification
Mbanyana and Robertson (2008) - A member of the simoni species-group. Nesomyrmex koebergensis is similar-looking to Nesomyrmex antoinetteae and Nesomyrmex mcgregori and is distinguished from the latter two species by the anterior clypeal margin, which is slightly concave laterally with the median portion not clearly defined from lateral portions. In the two latter species anterior clypeal margin is strongly concave laterally so that the median portion is clearly defined from the lateral portions and projects over the mandibles. It is also smaller (HL 0.813–0.902 versus 0.993–1.101). This species is also similar to Nesomyrmex ezantsi and distinguished from the latter species by the dorsum of head which has reticulate sculpture and overlaid by longitudinal rugulae; whereas in N. ezantsi the dorsum of head is predominantly smooth, with fine reticulate sculpture.

Distribution based on Regional Taxon Lists
Afrotropical Region: South Africa.

Nomenclature

 *  koebergensis. Nesomyrmex koebergensis Mbanyana & Robertson, 2008: 48, figs. 2d-f (w.) SOUTH AFRICA.

Worker
Holotype. HL 0.860, HW 0.677, HW1 0.738, CI 79, SL 0.623, SI 92, PW 0.492, ML 1.013, EL 0.258, EI 38.

Mandibles shagreenate – smooth but not shining. Clypeus predominantly smooth and shining, with few faint longitudinal striae. Anterior clypeal margin more-or-less convex except obtusely pointed medially. Eyes large, with 14 ommatidia in the longest row. Scapes of moderate length (SI 86). With head in full face view, hind margin slightly convex. Promesonotum in profile evenly convex. Metanotal groove conspicuously impressed. Dorsum of propodeum shallowly convex and sloping evenly into the declivity, which is almost straight. Propodeum armed with a pair of short triangular teeth. Metapleural lobes low and rounded. Anterior peduncle short and thick, with a small rounded subpetiolar process. Anterior and posterior faces of node convergent dorsally, rounding evenly into a convex dorsum. Postpetiole low and rounded in lateral view. Dorsum of head with reticulate ground sculpture, overlaid by longitudinal striations between the eyes. Promesonotal dorsum with punctate ground sculpture overlaid by longitudinal rugulae and transverse rugulae anteriorly. Propodeal dorsum and declivity with transverse striations, irregular anteriorly. Petiolar node and postpetiole with irregular striations. Base of first gastral tergite with short costulae and the rest of the tergite smooth and shining. Dorsum of head with erect hairs at the back of the head and four longitudinal lines of erect, acutely pointed hairs running between the eyes. The venter of head with four curved hairs and six straight hairs; sparse pubescence present. Promesonotal dorsum with at least 10 erect hairs, four on the propodeal dorsum, eight hairs on the petiolar node and eight hairs on the postpetiole. Regularly spaced suberect hairs on the gastral tergite and sternite. Colour uniformly light brown.

Paratypes. HL 0.813–0.902, HW 0.629–0.718, HW1 0.698–0.767, CI 75–80, SL 0.561–0.612, SI 83–95, PW 0.443–0.471, ML 0.936–1.084, EL 0.228–0.266, EI 37–40 (6 of 6 measured).

Mandibles either shagreenate, smooth and shining, or with fine longitudinal striations. Curved hairs on the venter of head range from two to four; straight hairs from three to four. Petiolar node with 4–8 hairs. Otherwise same as holotype.

Type Material
Holotype: South Africa: Western Cape: Koeberg Hill; 33°43’S 18°33’E; 03 October 1997, H.G. Robertson SAM-HYM-C010992. Paratypes: Six workers with same data as holotype.

Etymology
So named because the type material was collected from Koeberg Hill, which is inland from Bloubergstrand and not to be confused with Koeberg Nature Reserve that lies in the property of the Koeberg Nuclear Power Station north of Bloubergstrand.

References based on Global Ant Biodiversity Informatics

 * Hita Garcia F., Mbanyana N., Audisio T. L., and G. D. Alpert. 2017. Taxonomy of the ant genus Nesomyrmex Wheeler (Formicidae, Myrmicinae) in the Afrotropical region, with a review of current species groups and description of a new species of the N. angulatus group from Mozambique. European Journal of Taxonomy 258: 1–31.