Ocymyrmex afradu

Identification
Bolton and Marsh (1989) - afradu is closest related to Ocymyrmex kahas and Ocymyrmex flavescens, two other Namibian species. Apart from this, kahas and flavescens have the gaster yellowish, afradu has the gaster black; kahas and flavescens have the petiolar peduncle longer than the node whilst afradu has the node slightly longer than the peduncle. In full-face view the occipital margin is more strongly indented medially in afradu and flavescens than in kahas, and in afradu the petiole node is long, low and subclavate in profile.

Key to Ocymyrmex workers

Distribution based on Regional Taxon Lists
Afrotropical Region: Namibia.

Biology
All the species nest directly into the ground, either in the open or at the bases of plants. In the former case the nest is usually in sandy soil and a crater is formed around the entrance hole. Arnold (1916), who was acquainted with and reviewed the South African species, pointed out the remarkable swiftness of these ants, saying that for speed they far outstrip 'all other ants with which I am acquainted, so much so that they appear almost to fly over the surface of the ground'. Prins (1965) has recorded that Ocymyrmex species are granivorous but will also attack and destroy other insects. (Bolton 1981) Also see the Ocymymrex page for a more thorough review of the biology of ants in this genus.

Nomenclature

 *  afradu. Ocymyrmex afradu Bolton & Marsh, 1989: 1288 (w.) NAMIBIA.

Worker
Holotype. TL 5.8, HL 1.44, HW 1.36, CI 94, SL 1.34, SI 99, PW 0.84, AL 1.70.

Anterior clypeal margin with a broad and conspicuous cuticular flange, similar to that seen in kahas. Clypeus with a small and shallow anteromedian impression. Palp formula variable, not clearly visible in holotype but the single para type has the left maxillary palp with 4 segments, the right with 3; labial palpi both 3-segmented. Maximum diameter of eye 0.34, about 0.24 x HW. In full-face view the eyes distinctly breaking the outline of the sides of the head. Sides of head in front of eyes almost parallel, scarcely diverging anteriorly. Behind the eyes the sides convex and converging posteriorly, rounding broadly into the occipital margin which is itself indented medially. Promesonotum evenly convex in profile, the outline of the posterior portion of the mesonotum sloping and very shallowly concave. Propodeal dorsum weakly convex and rounding broadly and very evenly into the shallowly convex declivity. Bulla of metapleural gland projecting posteriorly and in profile almost obscuring the narrow and evenly rounded metapleural lobes. Petiole in profile with a relatively short peduncle and an elongate low subclaviform node; the length of the node slightly greater than that of the peduncle. In dorsal view the petiole node longer than broad, the postpetiole broader than long and broadest posteriorly. Sternite of postpetiole ventrally almost transverse, with only the shallowest concavity; lacking a strongly defined median longitudinal groove or impression. Gaster in profile with both the first tergite and the first sternite having shallowly convex outlines from their articulation with the postpetiole, lacking a basal constriction. In dorsal view the gaster without a narrow neck-like basal constriction. Dorsum of head glossy, very finely and weakly longitudinally costulate, and with ground-sculpture between the costulae very faint to absent. Cephalic costulae become weaker posteriorly and are almost effaced close to the occipital margin. Dorsal alitrunk evenly transversely sculptured except on pronotum where a patch of longitudinal sculpture runs forward from between the mesothoracic spiracles; the remaining dorsal pronotal sculpture arches around this patch and is relatively faint. Sides of alitrunk regularly sharply costulate everywhere, the individual costulae narrower and more widely spaced on sides of pronotum than elsewhere. Ground-sculpture faint to absent. Petiole with a few weak transverse rugae beneath the node but dorsally with extremely fine and very crowded faint ripple-like transverse rugulae; these are fainter still and tend to peter out on the sides of the node. Postpetiole feebly reticulate. First gastral tergite with superficial reticular patterning basally, which fades out apically on the sclerite. All dorsal surfaces of body with fine white to silvery hairs present. Head glossy dull red, remainder of body black but in places with a reddish or brownish tint.

Type Material
Holotype worker, Namibia ( = South West Africa): Namib Desert, Hunkab River, Skeleton Coast, 19 deg. 43 min. S., 13 deg. 11 min. E., 16.viii.1982, sample SC5 (A. C. Marsh). Paratype. One worker (dissected) with same data as holotype (BMNH). Dissected and mounted ventral side uppermost to show mouth-parts and ventral surfaces of body.