Hypoponera dulcis

This is one of the most widely distributed and most abundant Hypoponera species throughout sub-Saharan Africa.

Identification
A member of the dulcis group. See the nomenclature section below for additional identification details.

Key to Afrotropical and West Palaearctic Hypoponera

Distribution
This taxon was described from Tanzania. It is also found in South Africa, Eritrea, Kenya, Uganda, Zimbabwe, Angola, Cameroon, Central African Republic, Congo, Democratic Republic of Congo, Gabon, Sudan, Ivory Coast, Ghana, Guinea and Nigeria.

Biology
Bolton and Fisher (2011) - Can be extremely numerous in leaf litter samples. For instance, in Belshaw & Bolton (1994), dulcis (recorded as H.sp.2) accounted for more than three times the number of all the other Ghanaian Hypoponera species combined. On its own dulcis represented an incredible 51% of all the Ponerini retrieved and comprised 4.2% of all the ants collected in the survey. This preponderance is also reflected in B. L. Fisher’s collections in Cameroun, Gabon and the Central African Republic (unpublished data).

Nomenclature

 *  dulcis. Ponera dulcis Forel, 1907a: 2 (w.) TANZANIA. Arnold, 1915: 82 (q.). Combination in Hypoponera: Bolton, 1995b: 214. Senior synonym of lamottei, lotti, mandibularis, muscicola, rothkirchi, uncta, villiersi: Bolton & Fisher, 2011: 43.
 * uncta. Ponera dulcis var. uncta Santschi, 1914e: 7 (w.) SOUTH AFRICA. Combination in Hypoponera: Bolton, 1995b: 216. Junior synonym of dulcis: Bolton & Fisher, 2011: 43.
 * lamottei. Ponera lamottei Bernard, 1953b: 204, fig. 3 (w.) GUINEA. Combination in Hypoponera: Bolton, 1995b: 215. Junior synonym of dulcis: Bolton & Fisher, 2011: 43.
 * lotti. Ponera lotti Weber, 1942a: 45, fig. 5 (w.) SUDAN. Combination in Hypoponera: Bolton, 1995b: 215. Junior synonym of dulcis: Bolton & Fisher, 2011: 43.
 * mandibularis. Ponera mandibularis Bernard, 1953b: 205, fig. 3 (w.q.) GUINEA. Combination in Hypoponera: Bolton, 1995b: 215. Junior synonym of dulcis: Bolton & Fisher, 2011: 43.
 * muscicola. Ponera muscicola Weber, 1942a: 45, fig. 13 (q.) SUDAN. Combination in Hypoponera: Bolton, 1995b: 215. Junior synonym of dulcis: Bolton & Fisher, 2011: 43.
 * rothkirchi. Ponera rothkirchi Wasmann, 1918b: 145 (w.) CAMEROUN. Menozzi, in Eidmann, 1944: 434 (q.). Combination in Hypoponera: Bolton, 1995b: 216. Junior synonym of dulcis: Bolton & Fisher, 2011: 43.
 * villiersi. Ponera (Hypoponera) villiersi Bernard, 1953b: 206, fig. 3 (w.) GUINEA. Combination in Hypoponera: Bolton, 1995b: 216. Junior synonym of dulcis: Bolton & Fisher, 2011: 43.

Bolton and Fisher (2011) - As defined above, dulcis is perhaps the most easily recognised of all the Afrotropical Hypoponera. In brief, any specimen that combines the characters of eyes small but distinctly present, scapes relatively long, mesonotal-mesopleural suture (in profile) and metanotal groove (in dorsal view) both present, petiole scale-like, mesopleuron unsculptured and cinctus of second gastral tergite smooth at its base, is dulcis. However, there is some variation in the material examined that may suggest the presence of a second species within this group. In some darkly coloured specimens from Cameroun and Gabon (in BMNH and CASC), the mesonotum in profile is distinctly convex, whereas in all other material it is more or less flat. The degree of convexity varies and is sometimes difficult to assess as specimens in which the pronotum is fully flexed down with respect to the mesonotum appear more convex than those in which the two sclerites are aligned, because more of the curved anterior articulatory surface of the mesonotum is exposed. Coupled with this, the dorsum of the first gastral tergite in these workers where the mesonotum is more convex has conspicuous setae, whereas in the vast majority of specimens the setae on the first tergite are sparse and minute, and sometimes appear to be absent. The state in which the setae are reduced or absent applies to all queens examined, apparently regardless of the condition exhibited by their workers. None of the names included in the synonymic synopsis above, and none of Forel’s surviving specimens of dulcis, show either of the variations just discussed. It would perhaps be justifiable to nominate the variant forms as a separate species, but intermediates would, it is suspected, render the separation untenable. The resolution of this problem is beyond the scope of this contribution and must await individual analysis.

Variation in full adult colour seems insignificant as all intermediate shades between the lightest (dull yellow) and the darkest (dark brown) occur. No worker-queen intercaste forms have been seen in the hundreds of specimens examined, nor has any ergatoid male been detected; all queens and males seen have been fully alate.

Worker
Bolton and Fisher (2011) - Measurements: HL 0.54–0.63, HW 0.44–0.52, HS 0.490–0.570, SL 0.41–0.48, PrW 0.33–0.39, WL 0.73–0.84, HFL 0.44–0.54, PeNL 0.11–0.14, PeH 0.34–0.39, PeNW 0.23–0.28, PeS 0.227–0.267 (60 measured). Indices: CI 77–84, SI 92–102, PeNI 60–76, LPeI 32–39, DPeI 180–218.

Eyes present, black, small but distinct (always very conspicuous in specimens in alcohol), of 2–6 small ommatidia that are variable in size. The individual ommatidia are sometimes poorly defined or even partially fused; occasionally when several ommatidia are present one may be decidedly larger than the rest. Mandible most commonly with three relatively large teeth distally that are followed proximally by a variable number of smaller teeth or denticles that are all of approximately the same size, giving the margin a roughly serrate appearance. In some, one or two teeth in the serrate row may be somewhat enlarged. Scapes relatively long, SI 92–102; apex of scape, when laid straight back from its insertion in full-face view, varies from just failing to reach to slightly exceeding the midpoint of the posterior margin; SL/HL 0.74–0.83. Reticulate-punctate sculpture on cephalic dorsum very fine, frequently superficial but denser than on the dorsal pronotum, which is almost smooth with only very widely spaced minute superficial punctulae present. Mesonotal-mesopleural suture distinct on side of mesosoma. Metanotal groove conspicuous across dorsum of mesosoma, distinctly incised; mesonotum with a well-defined posterior margin. Mesopleuron mostly to entirely smooth and shining, unsculptured except for a few scattered minute pits. With propodeum in profile the length of the dorsum may vary from slightly to distinctly shorter than the full depth of the declivity. Petiole squamiform; node in profile tall and narrow, with the anterior and posterior faces converging dorsally to a short and narrowly rounded dorsum. Subpetiolar process in profile distinct but blunt, without acute or sharply developed angles anteriorly or posteriorly. In dorsal view the petiole node much broader than long (DPeI 180 or more), the dorsal surface very short from front to back. Maximum width of first gastral tergite in dorsal view sometimes slightly greater than width of the second tergite at its midlength, but often the two are about equal. Base of cinctus of second gastral tergite smooth and shining in dorsal view, without cross-ribs. Posttergite of second gastral segment, from posterior margin of cinctus to apex, broader than long. First gastral tergite pubescent and dorsally with standing setae that vary from absent to conspicuous (see discussion below). Full adult colour varies from dull yellow to dark brown; most common shades are light brown to medium brown.

Type Material
Bolton and Fisher (2011):

Holotype worker, TANZANIA: Arusha-chini (Katona) (not in, presumed lost.)

Holotype worker, SOUTH AFRICA: Zululand, Dukudu, dans la mousse, 27.vii.05 (I. Trågärdh) (not in, presumed lost).

Ponera rothkirchi Holotype worker, CAMEROUN: Kamerunburg, Soppo, 730 m., xii.1912 (von Rothkirch) [not examined directly].

Ponera lotti Syntype workers, SUDAN: Imatong Mts, Equatoria, Lotti Forest, 24.vii. - 5.viii.1939, nos. 1442, 1448 (N.A. Weber) [examined].

Ponera muscicola. Holotype queen, SUDAN: Imatong Mts, 25.vii.1939, 7200 ft, no. 1313, in wet moss in cavity of a tree (N.A. Weber) (not in MCZC, presumed lost)

Ponera lamottei Syntype workers, GUINEA: Nion, 700 m., 15.iv., st. 22 (Lamotte) [examined].

Ponera mandibularis. LECTOTYPE worker (teneral) (by present designation), GUINEA: Nimba (Lamotte) (MNHN) [examined].

Ponera (Hypoponera) villiersi Holotype worker (teneral), GUINEA: N.-E. du Nimba, mousses de la forêt (Villiers) (MNHN) [examined].