Polyrhachis volkarti Forel

Rigato, Fabrizio, 2016, The ant genus Polyrhachis F. Smith in sub-Saharan Africa, with descriptions of ten new species. (Hymenoptera: Formicidae), Zootaxa 4088 (1) : 44

Polyrhachis volkarti Forel

Polyrhachis revoili st. volkarti Forel, 1916: 453 . Holotype gyne, DEMOCRATIC REPUBLIC of the CONGO (H. Kohl). (MHNG) [examined]. [AntWeb photo: CASENT0910957]

Diagnosis. A medium sized revoili -group species with lobed clypeus, immarginate mesosoma (at most the pronotum bears a trace of lateral margination), and propodeal dorsum wider than long.

Holotype gyne. HL 1.50, HW 1.15, CI 77, SL 1.95, SI 170, FW 0.41, FI 36, MnL 1.78, ScW 1.45, WL 2.52, HTL 1.97.

Clypeus bearing a slightly protruding rectangular lobe at its anterior margin. Head in full face view oval, wider behind than in front, posterior margin evenly convex without distinct posterior corners; sides in front of the eyes straight. Eyes relatively large and convex. Ocelli small. Pronotal and propodeal sides immarginate. Pronotal teeth small and robust. Propodeal dorsum distinctly wider than long, arched both longitudinally and transversely. Propodeal ridges small and far apart, between them the propodeal dorsum smoothly merges into the declivity. Petiole with a mid pair of diverging and slightly backward bent spines, whose reciprocal distance is about twice the length of each spine, and a pair of much shorter lateral teeth raising near the bases of the spines. First gastral tergite anteriorly weakly concave.

Mandibles mostly smooth and shining, weakly shagreened at their insertion. Body and appendages finely reticulate-punctate; sculpturation stronger on the opaque head and mesosoma. Cephalic dorsum, except clypeus, with a superimposed longitudinal fine rugulation.

The whole body and appendages with fairly abundant standing hairs; longest hairs occur on scutellum and cephalic dorsum. Hairs on tibiae short, at most as long as maximum tibial width; hairs on scapes at most 1.5 as long as the maximum scape diameter. Pubescence whitish, moderately long and abundant throughout the body, but never hiding the sculpturation; on the gaster the distance between two adjacent elements is about equal to their length.

Colour mostly black, tibiae dark brown, tarsi apically partially ferrugineous. Funiculi mostly ferrugineous, except the 4 basalmost joints, which are basally darkened. Mandibles apically ferrugineous.

Worker. I assign to this species a series of workers from the Republic of the Congo (n=5).

HL 1.36–1.45, HW 1.11–1.16, CI 80–83, SL 1.74–1.85, SI 151–162, FW 0.40–0.41, FI 35–37, PW 1.00–1.06, WL 1.87–1.99, HTL 1.70–1.81. They look conspecific with the holotype gyne in all main features, even if sometimes an ill-defined trace of pronotal margination appears anteriorly behind the pronotal teeth.

Comment. The P. v o l k ar t i gyne looks very similar to the P. kohli gyne, except for the significant differences concerning pilosity and propodeum summarized under kohli . The workers I assigned to volkarti have pilosity and propodeal proportions highly comparable to those of the holotype gyne; yet further discoveries could demonstrate such workers to belong to a still undescribed species.

Material examined. REP. of the CONGO: Niari Region, 2.30339S 12.83902E, 705 m, 3.vii.2013, primary forest, canopy fogging, (L. Niemand) (5 w, AFRC: LN RC1 42, 90–93/CASENT0250012–15, CASENT0250031).