Polyrhachis revoili André

Rigato, Fabrizio, 2016, The ant genus Polyrhachis F. Smith in sub-Saharan Africa, with descriptions of ten new species. (Hymenoptera: Formicidae), Zootaxa 4088 (1) : 37-38

Polyrhachis revoili André

Polyrhachis revoili E. André, 1887: 285 . Holotype gyne, SOMALIA (Revoil) (MNHN) [examined].

Holotype gyne. HL 1.52, HW 1.25, CI 82, SL 1.81, SI 145, FW 0.46, FI 37, MnL 1.85, ScW 1.48, WL 2.52, HTL 1.89.

Clypeus bearing a slightly protruding, wide lobe, whose anterior margin is slightly arcuate and limited laterally by right angled corners. Head in full face view oval, wider behind than in front, posterior margin evenly convex without posterior corners; sides in front of the eyes anteriorly converging and straight. Eyes relatively large and convex. Ocelli small. Pronotal and propodeal sides immarginate. Pronotal teeth small and robust. Propodeal dorsum in dorsal view strongly transverse (at its widest point it is more the thrice as wide as medially long), arched both longitudinally and transversely. Propodeal dorsum posterolaterally with a pair of weak, distant propodeal ridges; between the ridges the propodeal dorsum smoothly merges into the declivity. Petiole with a median pair of diverging and slightly backward bent spines, whose reciprocal distance is somewhat twice the length of each spine, and a pair of shorter lateral spines, which are about half as long as the dorsal pair. First gastral tergite anteriorly concave.

Mandibles mostly smooth and shining, with superimposed elongate hair-bearing pits. Body and appendages reticulate-punctate; the sculpturation is stronger on the opaque head and mesosoma. Frons, vertex and scutum with superimposed longitudinal irregular rugulation.

The whole body and appendages with abundant, pale golden, fine standing hairs; longest hairs occur on cephalic dorsum, scapes, scutellum and gaster. Longest hairs on tibiae at most a little shorter than the maximum tibial width; longest hairs on scapes about twice as long as the maximum scape width. Pubescence pale, relatively short and abundant throughout the body, never hiding the sculpturation; on the gaster it is relatively short and moderately dense.

Body black, appendages chiefly dark brown. Mandibles apically ferrugineous as well as most of the antennal funiculi, whose 3 basalmost joints are proximally darkened.

Comment. The examination of the holotype gyne has shown it is very different from what Bolton (1973) and former authors thought. Bolton (1973) did not see the type and evidently relied on Forel and other authors about the identity of P. revoili . Forel himself (1894) described the revoili worker on the basis of a specimen from Delagoa (Mozambique) and believed André’s assurances about the conspecificity of his specimen with revoili . I have seen Forel’s worker and can confirm it corresponds to Bolton’s description. However, the type of P. revoili significantly differs from Forel’s specimen as well as from all other infraspecific taxa subsequently assigned to revoili or weissi . Bolton (1973) synonymized all of them either with revoili or with weissi . Bolton thought “ revoili ” and weissi differed in size, pilosity, and sculpturation. In my opinion, these differences are weak and unreliable (Bolton himself cast some doubts about their separation as distinct species) and I prefer to consider all of them as belonging to weissi (see below).

As P. revoili auct. does not match P. rev o i l i André, the latter remains known from the type only. As a consequence I assign all of the remaining forms to P. weissi Santschi (see under that heading).

The main differences between revoili André and weissi are as follows:

Polyrhachis revoili holotype (gyne) Polyrhachis weissi

Anterior clypeal margin with a shallow and wide lobe, with Anterior clypeal margin entire, not lobed distinct right-angled corners

Scape abundantly hairy, many hairs are as long as twice the Scape with standing hairs (when present) at most as long as maximum scape width scape width

Head in full face view elongate oval; its posterior margin Head in full face view distinctly trapezoidal; its posterior uniformly and strongly convex. margin wide and weakly convex and with distinct posterior

corners.

Dorsal cephalic sculpture irregular and mostly reticulate Dorsal cephalic sculpture regular, longitudinally finely

rugulose

P. rev o i l i can be compared to other species of the group bearing a clypeal lobe as well, e.g. volkarti and kohli ; yet, I could not find any worker looking conspecific with the revoili type.