Ocymyrmex velox

Marsh (1986b) notes that velox is restricted to the eastern gravel plains in the Namib Desert. Nests of the species are inconspicuous and normally have only one entrance hole. A semilunar crater of excavated material may occur near the nest entrance. He adds that velox is a diurnal insectivore which scavenges dead arthropods, but it will also prey on termites of the genus Hodotermes when eruptions of the latter occur.

Identification
A member of the velox group. Bolton and Marsh (1989) - The type-material and few samples of velox earlier available for examination (Bolton, 1981) all showed the same colour pattern. The alitrunk was dull red to blackish red, the head a lighter red, and the gaster lighter still, orange or even yellow in some individuals. Collections made by Alan Marsh in the Namib Desert at Etosha, in the Naukluft Mountains, and at 23 deg. 23 min. S., 15 deg. 32 min. E., show some velox with this colour pattern but others darker. In the latter the head is red but the remainder of the body is uniformly reddish black to black. Specimens collected by Hamish Robertson in the Namib Naukluft Park are the same as this dark material of Marsh's, but an even darker specimen, collected by H. Schlagbauer in the Brandburg Mountains, also has the head reddish black. Cephalic sculpture is also variable in intensity. It is usually quite faint but in some individuals it may be more strongly developed and conspicuous.

Bolton (1981) - O. velox is one of the seven known species in this genus which lack a conspicuous semicircular impression in the middle of the anterior clypeal margin. The others are Ocymyrmex turneri, Ocymyrmex laticeps, Ocymyrmex cursor, Ocymyrmex ankhu, Ocymyrmex zekhem and Ocymyrmex cavatodorsatus. Of these turneri is a small shiny species with large eyes which break the outline of the sides of the head, and cursor and laticeps have the dorsum of the head strongly sculptured and have the first gastral tergite constricted into a narrow neck basally. O. cavatodorsatus shares most characters with velox, but the shape of the alitrunk is very different; besides this cavatodorsatus is much smaller and has the sculpture of the alitrunk much reduced. Separation of velox from ankhu and zekhem is discussed under those species.

Distribution based on Regional Taxon Lists
Afrotropical Region: Angola, Namibia, South Africa, Zimbabwe.

Nomenclature

 *  velox. Ocymyrmex velox Santschi, 1932a: 387 (w.) NAMIBIA. Bolton, 1981b: 261 (q.). See also: Bolton, 1981b: 280; Bolton & Marsh, 1989: 1306.

Worker
Bolton (1981) - TL 10.0-10.7, HL 2.20-2.40, HW 2.08-2.30, CI 95-97, SL 2.10-2.29, SI 101-105, PW 1.30-1.42, AL 2.48-2.96 (8 measured).

Large species; anterior clypeal margin entire or very feebly eroded medially giving a weakly crenellated appearance, without a median semicircular impression. Maximum diameter of eyes 0.40-0.43, about 0.19-0.20 x HW. Frontal lobes distinctly convergent posteriorly, the occipital margin indented medially in full-face view. Antennal scapes relatively long, SI above. Promesonotum forming an even low convexity in profile which may be somewhat flattened above in some individuals. Propodeal dorsum more or less flat, usually sloping shallowly downwards posteriorly to the evenly rounded junction with the declivity; the alitrunk not saddle-shaped. Metapleural lobes low and rounded. Petiole node relatively large in profile, high, dome-like and evenly rounded, the anterior peduncle without a ventral process. In dorsal view the petiole node longer than broad. Postpetiole in dorsal view slightly broader than long. Base of first gastral tergite in dorsal view not forming a narrow bottle-neck-like constriction. The tergite basally is no wider than the post petiole but the sides diverge evenly from immediately behind the articulation. Sculpture of head very feeble, faint and even effaced in places, at most consisting of a few weak and superficial irregular rugulae. Ground-sculpture where present only of a weak superficial patterning or shagreening. Dorsal alitrunk transversely rugulose, with or without a patch of longitudinal sculpture on the pronotum and between the mesothoracic spiracles. Rugulae on the propodeal dorsum may be irregular or broken. Petiole and postpetiole dorsally only with superficial patterning, or the former with faint rugular vestiges. Ventral surface of petiole with weak transverse rugulae which may extend up the sides of the node and onto the dorsum, but these are vestigial in some individuals. Dorsal surfaces of head and alitrunk with hairs but these are very rare or even absent on the first gastral tergite. Alitrunk dull red to blackish red, the head a lighter red and the gaster lighter still, orange or even yellow in some individuals.

Type Material
Syntype workers, South West Africa: Otjimbimbi, Kunene R., iii.1923 (G. Arnold) (, NM - Bulawayo) [examined].

References based on Global Ant Biodiversity Informatics

 * Bolton B., and A. C. Marsh. 1989. The Afrotropical thermophilic ant genus Ocymyrmex (Hymenoptera: Formicidae). Journal of Natural History 23: 1267-1308.
 * IZIKO South Africa Museum Collection
 * Marsh A. C. 1986. Ant species richness along a climatic gradient in the Namib Desert. Journal of Arid Environments 11: 235-241.
 * Marsh A. C. 1986. Checklist, biological notes and distribution of ants in the central Namib Desert. Madoqua 14: 333-344.
 * Robertson H. G. 2000. Formicidae (Hymenoptera: Vespoidea). Cimbebasia Memoir 9: 371-382.
 * Santschi F. 1932. Formicides sud-africains. Pp. 381-392 in: Jeannel, R. (ed.) 1932. Société Entomologique de France. Livre du centenaire. Paris: Société Entomologique de France, xii + 729 pp.