Nesomyrmex mcgregori

Four specimens were collected in Renosterveld vegetation on tillite soils. These were the only specimens captured from the extensive pitfall trapping, Winkler bag sampling and sweeping done in the Nieuwoudtville area of the Northern Cape, so it appears to be a rare species.

Identification
Mbanyana and Robertson (2008) - Among the heavily sculptured species, N. mcgregori is similar looking to Nesomyrmex antoinetteae but is differentiated by the broader head (HW 0.836–0.934); the median portion of the dorsum of the head, which is smooth or reticulate and not covered by longitudinal rugulae; and the propodeum armed with acute spines. In N. antoinetteae head is narrower (HW 0.724–0.851); dorsum of the head is entirely covered by longitudinal rugulae; and the propodeum is armed with broad triangular teeth.

Key to Nesomyrmex of southern Africa

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

Nomenclature

 *  mcgregori. Nesomyrmex mcgregori Mbanyana & Robertson, 2008: 49, figs. 2j-l (w.) SOUTH AFRICA.

Worker
Holotype. HL 1.106, HW 0.934, HW1 1.005, CI 84, SL 0.816, SI 87, PW 0.666, ML 1.343 EL 0.295, EI 32.

Mandibles with fine longitudinal striations. Clypeus smooth medially, bordered by two pairs of longitudinal striations. Median portion of the clypeus convex but almost flattened anteriorly. Eyes with 15 ommatidia in the longest row. Hind margin of head in dorsal view straight. Promesonotum in profile evenly convex and the metanotal groove conspicuously impressed. Propodeal dorsum convex. Propodeal spines short and broad, approximately same length as metapleural lobes. Metapleural lobes low and rounded. Anterior peduncle short and broad with rounded subpetiolar process that is roughly the length of the metapleural lobes. Petiolar node with anterior and posterior faces each angled at about 125 degrees with respect to the dorsum; dorsum sharply angled with respect to the anterior face but rounds evenly into the posterior face. Dorsum of postpetiole rounded in profile with anteroventral process. Dorsum of head with punctulate to finely reticulate ground-sculpture, which is overlaid by fine, longitudinal rugulae in places. Promesonotal dorsum with fine predominantly longitudinal rugulae, irregular in places. Propodeal dorsum and declivity with transverse rugulae, becoming irregular near metanotal groove. Petiolar dorsum with predominantly transverse rugulae, becoming reticulate-rugose in places. Postpetiolar dorsum reticulate-rugose. Base of first gastral tergite with costulae and rest of tergite with fine, superficial reticulate pattern. Head with four longitudinal lines of erect, acutely pointed hairs running between the eyes. The venter of head with only one curved hair and five straight hairs; sparse pubescence present. Promesonotum with four erect hairs; propodeal dorsum with six erect hairs; petiolar node with four suberect hairs and postpetiole with at least 10 suberect hairs. Sparse pubescence present. Regularly spaced suberect hairs on tergite and sternite of the gaster. Colour uniformly light brown.

Paratypes. HL 0.993–1.101, HW 0.836–0.915, HW1 0.915–0.981, CI 83–84, SL 0.733–0.806, SI 88, PW 0.577– 0.629, ML 1.175–1.292, EL 0.268–0.293, EI 32(2of3measured).

Same as holotype but the eyes with 14 ommatidia in the longest row instead of 15 ommatidia as is the case with the holotype. The venter of head with 5–6 straight hairs; pubescence present.

Type Material
Holotype: South Africa: Northern Cape: Glen Lyon farm, Sheep’s Leg Site (4.62 km 153° SSE Nieuwoudtville), 31°24.359’S 19°08.895’E, collected in natural Renosterveld on tillite, Pitfall,11–18 October 2000, H.G. Robertson, D. Larsen, R. Adams, NW00-TN2-P09, SAM-HYM-C019144. Paratypes: South Africa: Northern Cape: Glen Lyon farm, Sheep’s Leg Site (4.62 km 153° SSE Nieuwoudtville), 31°24.359’S 19°08.895’E, collected in natural Renosterveld on tillite, Pitfall,11–18 October 2000, H.G. Robertson, D. Larsen, R. Adams, NW00-TN2-P05, SAM-HYM-C019143; Glen Lyon farm, Sheep’s Leg Site (4.62 km 153° SSE Nieuwoudtville), 31°24.359’S 19°08.895’E, collected in natural Renosterveld on tillite, Yellow pan trap, 11–18 October 2000, H.G. Robertson, D. Larsen, R. Adams, NW00-TN2-Y20, SAM-HYM-C019141.

Etymology
Named after Neil McGregor who until recently owned the farm Glen Lyon, where the holotype was collected, and who has done so much to stimulate research, conservation and tourism in the Nieuwoudtville region.