Hypoponera boerorum (Forel)

Bolton, B. & Fisher, B. L., 2011, Taxonomy of Afrotropical and West Palaearctic ants of the ponerine genus Hypoponera Santschi (Hymenoptera: Formicidae)., Zootaxa 2843, pp. 1-118 : 30-31

Hypoponera boerorum (Forel)

Ponera coarctata r. boerorum Forel , 1901: 339. Syntype workers, SOUTH AFRICA: Natal, alt. 5300 ft (1600 m. in description), no. 159 (Haviland) (MHNG) [examined]. [Raised to species: Santschi, 1938: 78. Combination in Hypoponera : Taylor, 1967: 12.]

WORKER. Measurements: HL 0.68 – 0.72, HW 0.56 – 0.60, HS 0.620 – 0.660, SL 0.46 – 0.50, PrW 0.45 – 0.48, WL 0.94 – 0.96, HFL 0.48 – 0.52, PeNL 0.18 – 0.20, PeH 0.40 – 0.42, PeNW 0.28 – 0.30, PeS 0.287 – 0.297 (6 measured). Indices: CI 82 – 86, SI 80 – 83, PeNI 61 – 65, LPeI 45 – 50, DPeI 140 – 158.

Eyes present, small and inconspicuous, depigmented in the syntypes. In full-face view apex of scape, when laid straight back from its insertion, distinctly fails to reach the midpoint of the posterior margin; SL/HL 0.68 – 0.70. Reticulate-punctulate sculpture of cephalic dorsum fine, but head distinctly more densely sculptured than pronotal dorsum. Propodeal dorsum smooth, with only faint traces of scattered minute punctulae. Mesonotal-mesopleural suture absent or with a weak vestige still visible. Metanotal groove distinctly incised across dorsum of mesosoma; mesonotum with a well-defined posterior margin. Propodeal declivity separated from side by a blunt angle or a weak margination, without sharp carinae. Mesopleuron smooth and shining. Petiole in profile with the anterior and posterior faces of the node convergent dorsally; node distinctly longer just above the anterior tubercle than at the dorsum. Sternite of petiole in profile with a rounded subpetiolar process that lacks sharp angles anteriorly or posteriorly. Anterior margin of subpetiolar process, near its base, with a conspicuous pit from which a sensory seta arises. Maximum width of first gastral tergite in dorsal view less than the width of the second tergite at its midlength. Base of cinctus of second gastral tergite with strong cross-ribs. Posttergite of second gastral segment, from posterior margin of cinctus to apex, distinctly broader than long. Punctures on disc of second gastral tergite superficial and densely crowded but not appearing microreticulate. With first gastral segment in profile, the dorsum with many short, stubbly, standing setae that arise along the entire length of the tergite. Full adult colour yellow.

At first glance boerorum appears to be a somewhat smaller version of spei , but the form of the pilosity on the dorsum of the first gastral tergite separates the two in the material available. In boerorum there are many standing setae that arise all over the sclerite, but all are short and stubble-like except for those at the extreme apex of the segment, which are notably longer. In spei the setae are less numerous but much longer, fine and very conspicuous. In addition, the subpetiolar process of boerorum is rounded, without a developed posteroventral angle, whereas in spei a posteroventral angle is often, but not always, present; see description of spei . Despite this, it should be stressed that boerorum and spei are extremely similar and the possibility that the latter will eventually prove to be a junior synonym of the former must be considered.

The original description of boerorum associated it with coarctata (type-species of Ponera ) and was superficial in the extreme. No useful discriminating characters were documented and it was vaguely compared with lucida Emery, now a junior synonym of Ponera coarctata from Turkestan, and with mackayensis (Forel) , an unrelated Hypoponera species from Australia. When spei was described, nearly a decade later, no mention was made of boerorum , although the type-localities of the two were both in Natal and probably only a few miles apart. Because the description of spei was marginally better than that of boerorum , it became the template for understanding the species, and boerorum was effectively forgotten until Santschi (1938) elevated the name to species rank. He did this merely by pointing out a few differences between coarctata and boerorum , but failed to compare the latter with any other African congener.

Both boerorum and spei usually have a distinct pit near the anterior margin of the subpetiolar process, from which a sensory seta arises. The seta and its pit are very common in Afrotropical Hypoponera and are easily visible in many species, but in these two the pit appears hypertrophied, by comparison with other species, and in the most extreme examples appears very similar to the thin-spot or fenestra that is diagnostic of Ponera . See comments on worker characters under the diagnosis of the genus.

Material examined. South Africa: Natal (Haviland).