Hypoponera austra

Specimens have been collected in montane forest, little else is known of their biology.

Identification
A member of the abeillei group.

Bolton and Fisher (2011) - Hypoponera natalensis and Hypoponera austra share the character of having a transverse impression across the base of the posterior face of the petiole node, above the peduncle. The impression is not deep and may be difficult to discern in direct posterior view, but in posterodorsal view its upper margin appears as a dark line, located well above the peduncle. In natalensis the impression terminates at either side in a short oblique cuticular ridge that is usually clearly visible in profile, but this may be missing in austra. A similar transverse impression can be seen in Hypoponera exigua and Hypoponera traegaordhi, but in these the impression is spanned by a series of short cuticular ridges that radiate upward from the posterior peduncle. The radiating ridges of exigua and traegaordhi are convergent on the species related to Hypoponera jeanneli and Hypoponera hebes, but in these the ridges are directly on the flat posterior surface and are not confined within an impression that has a sharply delineated upper margin.

H. natalensis and austra are best separated by the condition of the petiole, which in natalensis is shorter and higher in profile (LPeI 41–47) and distinctly broader in relation to its length in dorsal view (DPeI 160–187), than in austra (LPeI 47–56, DPeI 137–150). In more relative features, the metanotal groove often retains a vestigial presence in natalensis but is always absent in austra, and the cross-ribs of the cinctus of the second gastral tergite are distinctly coarser and more strongly developed in natalensis than in austra.

A third species in this complex is Hypoponera meridia, which although lacking the transverse impression on the posterior surface of the petiole, often exhibits a slender transverse ridge immediately above and adjacent to the posterior peduncle. This is a smaller species, HW 0.38–0.42, SL 0.32–0.36, PeH 0.28–0.32, as compared to the combined measurements of HW 0.46–0.57, SL 0.38–0.50, PeH 0.34–0.44 in natalensis and austra.

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

Castes
Specimens from Table Mountain and Knysna are very worker-like but have partially depigmented distinct eyes of about 7–10 ommatidia, much larger and much more obvious than in true workers. A single specimen from Newlands Forest has a strangely thickened petiole, with LPeI 60, DPeI 119. Other specimens from the same series are quite ordinary and one is mounted on the same pin as the oddity. Whether this is teratological, or is some kind of intercaste, or perhaps represents a socially parasitic form (unlikely) is not known. (Bolton and Fisher 2011)

Nomenclature

 *  austra. Hypoponera austra Bolton & Fisher, 2011: 27, figs. 7-9 (w.q.,ergatoid q.) SOUTH AFRICA.

Worker
(holotype in parentheses). Measurements: HL 0.59–0.63 (0.62), HW 0.46–0.50 (0.48), HS 0.525–0.560 (0.550), SL 0.38–0.42 (0.40), PrW 0.36–0.38 (0.36), WL 0.77–0.88 (0.86), HFL 0.38–0.44 (0.42), PeNL 0.18–0.20 (0.20), PeH 0.34–0.37 (0.36), PeNW 0.26–0.28 (0.28), PeS 0.260–0.280 (0.280) (12 measured). Indices: CI 75–79 (77), SI 80–84 (83), PeNI 69–78 (78), LPeI 47–56 (56), DPeI 137–150 (140).

Eyes vestigial to absent, sometimes with a small depigmented spot that appears to be the remnant of a single ommatidium; sometimes no trace of an eye spot. 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 0.63–0.67. Reticulate-punctulate sculpture of cephalic dorsum fine, but head more densely sculptured than pronotal dorsum. Lateroventral surfaces of head with extremely feeble superficial punctate sculpture, the surfaces almost smooth. With mesosoma in dorsal view the metanotal groove absent. Propodeal declivity separated from sides by blunt angles or weak marginations. Mesopleuron smooth and shining. Petiole in profile with the node relatively short and of moderate height, the anterior and posterior faces parallel or at most only extremely feebly convergent dorsally; dorsal surface shallowly broadly convex. Subpetiolar process shallow, usually with a low, blunt ventral angle. Posterior surface of petiole node with a shallow transverse groove or impression above the peduncle, the upper margin of the impression appears as a transverse dark line or ridge in posterodorsal view. Without cuticular ridges that radiate upwards into the impression from the posterior peduncle. 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 short but conspicuous cross-ribs. Posttergite of second gastral segment, from posterior margin of cinctus to apex, distinctly broader than long. Disc of second gastral tergite shallowly reticulate-punctate to microreticulate. With first gastral segment in profile, the dorsum with sparse, short, standing setae. Full adult colour yellowish brown to light brown.

Type Material
Holotype worker, South Africa: W. Cape Prov., Table Mtn, Orange Kloof N.R., 34°00.1’S, 18°23.5’E, 125 m., 15.xii.1997, sifted litter (leaf mold, rotten wood), montane rainforest, #1542(18)-1 (B.L. Fisher). Paratypes. 12 workers and 1 dealate queen with same data as holotype, all #1542 but coded (2)-3, (5)-1, (6)-3, (8)- 2, (10)-6, (14)-3, (15)-1, (17)-1 (queen), (19)-1, (20)-5, (LO)-6 (CASC, ).