Hypoponera occidentalis

Known from specimens collected in a variety of forest types, these ants have been discovered from ground litter, under objects on the ground and in rotten wood.

Identification
See the nomenclature section below.

Distribution
Reported from Uganda, Guinea, Ivory Coast, Ghana, Cameroon, Gabon, Equatorial Guinea, Central African Republic, Kenya, Tanzania and Zimbabwe.

This taxon was described from Guinea.

Castes
Queens are known but are undescribed. Males have not been collected.

Nomenclature

 *  occidentalis. Ponera (Hypoponera) occidentalis Bernard, 1953b: 205, fig. 3 (w.) GUINEA. Combination in Hypoponera: Bolton, 1995b: 215. Senior synonym of intermedia: Bolton & Fisher, 2011: 78.

Bolton and Fisher (2011) - Seven Afrotropical species of Hypoponera are known that have the following characters in combination: metanotal groove absent from dorsum of mesosoma; base of cinctus of second gastral tergite smooth and shining, without cross-ribs; posterior surface of petiole node without vertical cuticular ridges basally; maximum width of first gastral tegite in dorsal view greater than width of second tergite at its midlength; disc of second gastral tergite with spaced, small punctures that are separated by wide areas of polished cuticle. Two species, Hypoponera aprora and Hypoponera dis, both Tanzanian endemics, are small with maximum dimensions of HL 0.53, HW 0.42, SL 0.36, PeH 0.32, HS 0.470 and PeS 0.250; all other species in the complex are considerably larger than these. A single species, Hypoponera producta, has relatively long scapes, with SI 99–108. Hypoponera importuna and Hypoponera comis have the petiole node relatively short and very broad, with DPeI 182–200 (mean of 190). In the other five species combined DPeI is 133–180. Only a very few individuals of occidentalis approach the upper limits of this range, but in that species the mean value for DPeI is 165. The final species, Hypoponera odiosa, is very closely related to occidentalis and is best separated by the characters noted in the key.

No obvious intercastes could be discerned in the occidentalis material examined (i.e. no worker-like specimens with eyes of 10 or more ommatidia), but it is possible that the specimens with 3–4 ommatidia may represent inter-castes with much smaller eyes than is usual.

The series recorded below from Zimbabwe (MHNG, BMNH) is slightly different from the mass of examined material. In these specimens the punctate sculpture on the first gastral tergite, especially on the side just above the tergosternal suture, is fainter and more superficial, but this is more a matter of degree than of actual difference in form. The series is currently retained within occidentalis, because the specimens match the diagnostic characters given above, to be reassessed when more samples have accumulated.

Worker
Bolton and Fisher (2011) - Measurements: HL 0.61–0.75, HW 0.48–0.60, HS 0.545–0.670, SL 0.44–0.55, PrW 0.38–0.48, WL 0.84–1.08, HFL 0.46–0.58, PeNL 0.20–0.24, PeH 0.42–0.52, PeNW 0.32–0.39, PeS 0.310–0.377 (40 measured). Indices: CI 76–82, SI 86–96, PeNI 76–89, LPeI 40–48, DPeI 150–180.

Eyes variably developed; sometimes absent, sometimes a vague eye spot, but frequently with 1 and less commonly with 3–4 small ommatidia discernible. Apex of scape, when laid straight back from its insertion, just fails to reach, or less commonly just touches, the midpoint of the posterior margin in full-face view; SL/HL 0.68–0.75. Cephalic dorsum sharply reticulate-punctate. Pronotal dorsum almost smooth, with spaced, minute, superficial punctures, obviously much less strongly and densely sculptured than cephalic dorsum. Metanotal groove absent from dorsum of mesosoma or at most with a faint impression. Mesonotal-mesopleural suture feebly present to absent on side of mesosoma. Propodeum weakly marginate between declivity and side. Posterior surface of petiole node without short cuticular ridges that radiate upward from the peduncle. Node of petiole in profile tall and relatively thick, with the anterior and posterior faces parallel or very nearly so and the dorsum convex. Subpetiolar process with a distinct ventral angle. Maximum width of first gastral tergite in dorsal view greater than the width of the second gastral tergite at its midlength. Base of cinctus of second gastral tergite glossy and polished, without trace of cross-ribs. Midline length of second gastral posttergite, from posterior margin of cinctus to apex, is less than the width of the segment at its midlength. Disc of second gastral tergite with sharply incised, small punctures that are widely separated by areas of glossy cuticle; the diameters of the punctures are less than the distances that separate them. First and second gastral tergites dorsally pubescent and with a number of short, standing setae that conspicuously project above the level of the pubescence in profile.

Type Material
Bolton and Fisher (2011) - Syntype workers, GUINEA: Crête de Nion, 1300 m, 19.iv., st. B6 26 (Lamotte) [examined].

Ponera (Hypoponera) intermedia Holotype worker (teneral), GUINEA: ravin 1 du Mont Tô, st. B1 30 (Lamotte) (MNHN) [examined].

Additional References

 * Bolton, B. & Fisher, B.L. 2011. Taxonomy of Afrotropical and West Palaearctic ants of the ponerine genus Hypoponera Santschi. Zootaxa 2843: 1-118.