Hypoponera defessa

Identification
See the nomenclature section below.

Distribution
This taxon was described from Ghana. It is also found in Cameroon, Gabon, Ivory Coast and Togo.

Nomenclature

 *  defessa. Hypoponera defessa Bolton & Fisher, 2011: 38, figs. 25-27 (w.) GHANA.

Each of the samples noted below consists of only one or a few specimens. Hypoponera defessa is closely related to two other species; the widespread Hypoponera fatiga and the Ivory Coast and Ghana species Hypoponera lassa. All three are small (HW 0.36–0.46), eyeless, brownish-yellow to brown species in which the metanotal groove is absent, the cinctus of the second gastral tergite has cross-ribs and the disc of the second gastral tergite is superficially reticulate-punctate to microreticulate. H. defessa is distinguished from both fatiga and lassa by its lack of a raised median longitudinal clypeal ridge, which is conspicuous in the last two named. In addition, the petiole node in defessa is columnar in profile and relatively stout (LPeI 46–53), is D-shaped in dorsal view and is longer relative to its width (DPeI 134–150). In fatiga and lassa the correponding indices combined are LPeI 37– 44 and DPeI 155–180. In the order lassa – defessa – fatiga the three species show a morphoclinal reduction in the density and intensity of the punctate sculpture of the lateroventral surfaces of the head. In lassa the sculpture is nearly reticulate-punctate, with the individual punctures sharply defined and closely packed, the distances between the punctures generally less than the puncture diameters; in defessa the punctures are still sharply defined but more widely spaced, the distances between the punctures equal to or greater than the puncture diameters; in fatiga the punctures are widely spaced, minute, feeble and superficial. The ratio SL/HL shows a combined range of 0.65–0.71 in defessa and lassa, but tends to average somewhat lower in fatiga, 0.60–0.67.

A single specimen from Togo (MHNG) is somewhat at variance with the description just given. Most of its dimensions and indices fall easily within the range given, but its HW 0.54 and SL 0.42 are slightly too high. Coupled with this, the anterior and posterior faces of its petiole node in profile are weakly convergent dorsally. It is suspected that this specimen may represent an intercaste rather than a sibling species, but this cannot be proved at present.

H. defessa should not be confused with the common, yellow, Hypoponera coeca as the latter has a median clypeal crest, has dorsally convergent anterior and posterior faces to the petiole node in profile, tends to be smaller (HL 0.47–0.52, HS 0.415–0.465, SL 0.30–0.35, PeH 0.25–0.31, PeS 0.187–0.233), with slightly broader head and shorter scape (CI 77–84, SI 80–89) and has the punctulate sculpture of the lateroventral areas of the head very sparse, superficial and faint.

Worker
(holotype in parentheses). Measurements: HL 0.57–0.61 (0.58), HW 0.43–0.46 (0.45), HS 0.500–0.530 (0.515), SL 0.39–0.41 (0.40), PrW 0.32–0.35 (0.32), WL 0.74–0.80 (0.76), HFL 0.40–0.43 (0.42), PeNL 0.16–0.19 (0.17), PeH 0.34–0.37 (0.36), PeNW 0.23–0.26 (0.24), PeS 0.243–0.270 (0.257) (11 measured). Indices: CI 74–78 (78), SI 87–93 (89), PeNI 70–76 (75), LPeI 46–53 (47), DPeI 134–150 (141).

Eyes absent. Median portion of clypeus evenly convex from side to side, without a raised median longitudinal ridge or crest except posteriorly, between the extreme anterior portions of the frontal lobes. Apex of scape, when laid straight back from its insertion, distinctly fails to reach the midpoint of the posterior margin in full-face view; SL/HL 0.65–0.70. Reticulate-punctate sculpture on cephalic dorsum fine and dense, the punctures crowded, small, and sharply defined. Lateroventral areas of head distinctly punctate, the individual punctures sharply incised but much more widely spaced than on the dorsum. Punctate sculpture on disc of pronotum very weak, much less strongly defined, more sparse and more widely spaced than on cephalic dorsum. Metanotal groove entirely absent from dorsum of mesosoma. Sides of propodeal declivity bluntly angular, not carinate. Petiole node in dorsal view thickly D-shaped, with a strongly convex anterior face that is continuous with the sides, the anterior and lateral faces form a single continuous convexity. Petiole node in profile thickly columnar, with parallel sides from just above tubercle to apex; dorsum shallowly convex. Posterior surface of petiole node without radiating cuticular ribs above the peduncle. Subpetiolar process with a curved and obliquely descending anterior face, a ventral angle that may be sharp or blunt and a short, ascending posterior surface. Base of cinctus of second gastral tergite densely cross-ribbed. Disc of second gastral tergite microreticulate to superficially reticulate-punctate; without sharply incised widely separated punctures. Maximum width of first gastral tergite in dorsal view is subequal to the width of the second tergite at its midlength. Midline length of second gastral posttergite, from posterior margin of cinctus to apex, is about the same as the maximum width of the segment. Suberect to erect setae on dorsum of first gastral tergite sparse and short, only about half the length of the setae on the posterodorsal margin of the node. Full adult colour light brown, the appendages lighter.

Type Material
Holotype worker (upper specimen of two on pin), Ghana: Poano, ix.1992 (R. Belshaw). Paratypes. 3 workers with same data as holotype, one mounted below holotype (BMNH).