Holcoponera albiclava

The types were ground foragers collected in forest, which is all that is known about the biology of this species.

Identification
Lattke (2004) - Apical four funicular segments white, the rest of antenna brown; occipital lobes absent; anterior clypeal margin with two lateral blunt angles and median quadrate projection. Humeri rounded, without crests; body mostly smooth except for longitudinal costulae on lower part of mesonotum and metapleura; metacoxal dorsum without a denticle. Large, HL 1.34-1.40, WL 1.89-2.11mm.

Distribution based on Regional Taxon Lists
Indo-Australian Region: Solomon Islands.

Castes
Males have not been collected.

Nomenclature

 * . Wheeleripone albiclava Mann, 1919: 283, fig. 3 (w.) SOLOMON IS (Isabel I.).
 * Type-material: 4 syntype workers.
 * Type-locality: Solomon Is: Isabel I., Fulakora, 1916 (W.M. Mann).
 * Type-depository: MCZC.
 * Lattke, 2004: 58 (q.).
 * Combination in Gnamptogenys: Brown, 1958g: 227;
 * combination in Holcoponera: Camacho, Franco, Branstetter, et al. 2022: 11.
 * Status as species: Wheeler, W.M. 1935g: 10; Brown, 1958g: 227; Bolton, 1995b: 208; Lattke, 2004: 56 (redescription); Sarnat, et al. 2013: 69; Camacho, Franco, Branstetter, et al. 2022: 11.
 * Distribution: Solomon Is.

Lattke (2004) - Mann’s (1919) description is comprehensive, but I disagree with his assertion that the antennal scapes surpass the posterior occipital margin by less than their apical width. This length was consistently found to be longer than the apical width, even taking into account the apical flange of the scape. The anterior clypeal border is strigulose and not densely punctulate as he describes. The mandibles are just as shiny as the rest of the body, and the pilosity is yellowish, not black as in Mann (1919). The only other Holcoponera with a similarly colored antenna, Holcoponera lucida, is also from the Solomon Islands but has only been found on Malaita, not Guadalcanal. It is much smaller (HL < 1.0; WL < 1.3 mm) than H. albiclava and has a metacoxal tooth and a smooth mesonotum. They both share the pointed anteroventral pronotal corner, but H. lucida lacks the median anteroclypeal projection. This species shares with Holcoponera solomonensis, another Solomon Islands endemic, the single stout seta on the basal fore tarsal concavity, lack of a metacoxal spine, and exposure of the dorsal lobe of the torulus. The postpetiolar process in H. albiclava, having two lateral lobes and a median denticle, seems similar to that of H. solomonensis, which also appears trilobed. The apparent lack of a clypeal lamella in H. albiclava is unique in Holcoponera, though the anterior clypeal projection could be derived from the lamella. The petiolar node of H. albiclava is not as high and compressed as in other members of this group, but its shape is also unlike the regular convexity of the Gnamptogenys coxalis or Gnamptogenys laevior group, with a higher posterodorsal margin on the node than its anterodorsal margin.

Worker
Lattke (2004) - Metrics (n = 3): HL 1.34-1.40, HW 1.12-1.25, ML 0.77-0.85, SL 1.29-1.40, ED 0.19-0.21, WL 1.89-2.11 mm. CI 0.84-0.89, SI 1.12-1.16, MI 0.68-0.69, OI 0.16-0.17. Head subrectangular in frontal view, wider posterad than anterad, sides slightly concave, posterior margin medially excised; frons with longitudinal costae fading laterally to smooth surface with piligerous punctae, costae extend medially to vertex; vertex otherwise mostly smooth and rounded, not sharply separated from frons; occipital lobes absent. Frontal lobe brief, exposing dorsal lobe of torulus in frontal view; scape surpasses posterior cephalic margin by more than one apical width, shaft gradually widening apically, cross section oval, dorsum smooth with sparse punctulae, scape with abundant appressed pilosity present; first funicular segment at least twice as long as wide. Clypeus longitudinally costulate, median shallow sulcus present; anterior margin with two lateral blunt angles and median quadrate projection, lamella apparently absent; eye with convex cross section; mandibular dorsum smooth with punctulae, masticatory border denticulate.

Pronotum with anteroventral angle in lateral view, ventral sulcus present; promesonotal suture distinct from side to side, metanotal sulcus indistinct; mesosoma mostly smooth, mesonotum longitudinally costulate; anepisternum indistinct, except for occasional brief impressed line; posterior metapleuron with longitudinal carinulae; propodeal spiracle separated by approximately one diameter from declivity, propodeal declivity relatively flat to slightly convex. Dorsal mesosomal margin evenly convex in lateral view, curving into straight propodeal margin. Petiole anterodorsally convex in lateral view, more sharply curved posterad than anterad, posterior margin brief, vertical; petiolar spiracles situated ventrad of anterolateral lobes, anterior crest absent; subpetiolar process triangular, anteriorly projecting; petiole and gaster mostly smooth; procoxa laterally smooth; fore tarsal base with single stout seta opposite strigil, dorsum punctulate; second fore tarsal segment with 6 apical stout setae; fore tarsal segments 2-4 slightly longer than wide; metacoxal dorsum unarmed, slight elevation or corner may be present. Body without standing pilosity; appressed hairs present on funiculus, coxae, tarsi, and gastral apex. Body brown; legs and mandibles ferruginous; antennae ferruginous except for white terminal four segments of funiculus.

Queen
Lattke (2004) - Metrics (n = 1): HL 1.56, HW 1.37, ML 0.91, SL 1.47, ED 0.26, WL 2.44 mm. CI 0.88, SI 1.07, MI 0.66, OI 0.19. Very much as worker except for caste differences. Metapleuron with larger patch of longitudinal costulae that extends dorsally to bottom edge of propodeal spiracle. Mesoscutum and scutellum longitudinally costulate.

Type Material
Lattke (2004) - Syntype workers: Solomon Islands, Isabel Island, Fulakora (Mann) [Examined].

References based on Global Ant Biodiversity Informatics

 * Brown W. L., Jr. 1958. Contributions toward a reclassification of the Formicidae. II. Tribe Ectatommini (Hymenoptera). Bulletin of the Museum of Comparative Zoology 118: 173-362.
 * Lattke J. E. 2004. A taxonomic revision and phylogenetic analysis of the ant genus Gnamptogenys Roger in Southeast Asia and Australasia (Hymenoptera: Formicidae: Ponerinae). University of California Publications in Entomology 122: 1-266.
 * Mann W. M. 1919. The ants of the British Solomon Islands. Bulletin of the Museum of Comparative Zoology 63:273-391.
 * Mann, W.M. 1919. The ants of the British Solomon Islands. Bulletin of the Museum of Comparative Zoology of Harvard College 63: 273-391
 * Wheeler W.M. 1935. Check list of the ants of Oceania. Occasional Papers of the Bernice Pauahi Bishop Museum 11(11):1-56.
 * Wheeler, William Morton.1935.Checklist of the Ants of Oceania.Occasional Papers 11(11): 3-56
 * Wilson Edward O. 1959. Adaptive Shift and Dispersal in a Tropical Ant Fauna. Evolution 13(1): 122-144