Hypoponera exigua Bolton & Fisher, 2011

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 : 50

Hypoponera exigua Bolton & Fisher sp. n.

(Figs 40 – 42)

WORKER (holotype in parentheses). Measurements: HL 0.66 – 0.68 (0.66), HW 0.52 – 0.54 (0.53), HS 0.590 – 0.610 (0.595), SL 0.44 – 0.48 (0.44), PrW 0.39 – 0.43 (0.41), WL 0.86 – 0.90 (0.88), HFL 0.45 – 0.48 (0.46), PeNL 0.16 – 0.19 (0.18), PeH 0.40 – 0.43 (0.42), PeNW 0.30 – 0.32 (0.31), PeS 0.293 – 0.313 (0.303) (10 measured). Indices: CI 78 – 80 (80), SI 83 – 89 (83), PeNI 72 – 79 (76), LPeI 39 – 45 (43), DPeI 168 – 188 (172).

Eyes absent. Apex of scape, when laid straight back from its insertion, just fails to reach the midpoint of the posterior margin in full-face view; gap between apex of scape and midpoint of margin ca 0.10 × SL, about half the apical width of the scape; SL/HL 0.67 – 0.71. Cephalic dorsum finely and densely reticulate-punctate. Lateroventral areas of head with small, evenly spaced, superficial punctures. Punctate sculpture on dorsum of mesosoma faint and superficial, almost entirely effaced on propodeum. Mesonotal-mesopleural suture absent or extremely feebly present. Mesopleuron smooth, its anterior margin bluntly angulate behind the anterior coxa. Metanotal groove entirely absent from dorsum. Declivity of propodeum separated from sides by distinct marginations, the latter conspicuous in profile. Posterior surface of petiole node with a series of 4 – 5 short cuticular ridges at its base which radiate upward from the posterior peduncle. The cuticular ridges terminate dorsally in a darkly coloured, arched transverse rim or carina that is more darkly coloured than the surrounding cuticle. This transverse rim marks the upper boundary of a shallow transverse depression, within which the cuticular ridges are located. The depression terminates at each side in a short, vertical carina that ascends the posterolateral edge of the node and is visible in profile. With petiole node in profile the anterior and posterior faces are approximately parallel and the dorsum is distinctly rounded. Subpetiolar process an elongate low lobe that terminates in a short ascending angle at about the midlength of the sternite. Base of cinctus of second gastral tergite with a continuous row of strong cross-ribs. Maximum width of first gastral tergite in dorsal view is subequal to, or slightly greater than, the width of the second tergite at its midlength. Midline length of second gastral posttergite, from posterior margin of cinctus to apex, is distinctly less than the maximum width of the segment. Disc of second gastral tergite with small punctures that are relatively close-packed but narrowly separated by smooth cuticle; spaces between the punctures are less than the puncture diameters. First gastral tergite in profile with very short standing setae that project only slightly above the level of the decumbent pubescence. Full adult colour light brown.

Holotype worker, Ethiopia: Bale reg., Bale Mts N.P., Harenna For., Katcha area, 2400 m., 24.viii.1998, #10c, leaf litt.+bushpig drop., in For. (G. Cuccodoro & D. Erne) (MHNG).

Paratypes. 30 workers with same data as holotype (MHNG, BMNH, CASC, BBRC).

At first glance exigua is very similar to the South African traegaordhi , especially as regards the distinct combination of transverse depression and vertical cuticular ribs at the base of the posterior face of the petiole node. But traegaordhi is a distinctly smaller species in which, apart from the differences noted in the key, the apex of the scape does not approach the midpoint of the posterior margin of the head nearly as closely as in exigua .