Polyrhachis revoili

Nothing is known about the biology of .

Identification
A member of the Polyrhachis revoili species-group.

Rigato (2016) - The main differences between revoili and Polyrhachis weissi are as follows:

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

Bolton (1973) - The present study implies that revoili and Polyrhachis weissi must be treated as separate although very closely related species. The characters used to separate them appear quite trivial, but are apparently consistent. Further study may show this premise to be incorrect but for the present the species emerge as indicated below.

P. revoili is a larger, noticeably more thickset species (PW 1.40 or more) with a distribution limited to the southern savannah and veldt regions. Erect hairs are more numerous everywhere ( > 30 on each antennal scape) and the pubescence is dense enough to hide the sculpturation of the alitrunk, at least in part. Of the constituent segments of the dorsal alitrunk only the pronotum is distinctly longitudinally rugose, whilst on the other surfaces the rugae are disorganised or a rugoreticulum is present. On the other hand, weissi is a smaller, more slender species (PW 1.26 or less) restricted to the forested areas of West and Central Africa. Erect hairs are more sparse (from none to about 10 on each scape) and the pubescence is fine and short, not masking the sculpturation. The entire dorsum of the alitrunk is sharply longitudinally rugose.

Distribution based on Regional Taxon Lists
Afrotropical Region: Somalia.

Nomenclature

 *  revoili. Polyrhachis revoili André, 1887: 285 (q.) SOMALIA. Forel, 1894b: 71 (w.); Forel, 1916: 452 (m.). Combination in P. (Pseudocyrtomyrma): Emery, 1921e: 23; Emery, 1925b: 207; in P. (Myrma): Forel, 1916: 452; Wheeler, W.M. 1922a 999; Bolton, 1973b: 338.

Worker
Bolton (1973) - TL 6.1-6.5, HL 1.51-1.59, HW 1.44-1.48, CI 93-95, SL 1.63-1.66, SI 112-113, PW 1.40-1.48, MTL 1.66-1.70. (7 measured.)

Anterior clypeal margin arcuate and entire or with a very shallow, small median emargination. Eyes convex, the sides of the head in front of the eyes weakly convex and converging anteriorly. Behind the eyes the sides round into the very shallowly convex occipital margin. Alitrunk not marginate, transversely convex dorsally. The sutures reduced to faint lines; promesonotal suture rather better defined than the metanotal groove, which is not impressed. Pronotum very broad, more than twice the width of the propodeum measured across the teeth. Pronotum with a pair of short, acute spines of variable length, the propodeum with a pair of upcurved teeth. Petiole armed with a long pair of spines dorsally and a shorter, upcurved lateral pair. Anterior face of first gastral segment shallowly concave medially.

Head, body and appendages everywhere with abundant, erect, white to greyish hairs. Pubescence greyish and dense, partially or wholly concealing the sculpturation upon the dorsum of the alitrunk.

Head finely, longitudinally striate-rugose. Dorsum of the pronotum similar to head but rugae less distinct and with a tendency to meander. On the dorsa of the mesonotum and propodeum the rugae are disorganised or arranged into a fine, loose rugoreticulum. Gaster finely reticulate-punctate or superficially reticulate. Colour usually uniform black, dull, with the gaster shining. The head is usually more shiny than the alitrunk. Legs may be black, black-brown, or red-brown, and the antennal funiculi are often brown towards the apex.

Queen
Rigato (2016) - Holotype. 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.

Bolton (1973) - As worker apart from the usual differences associated with caste. The pronotal spines and propodeal teeth are reduced; the latter may even be absent.

Type Material
Rigato (2016) - Holotype gyne, SOMALIA (Revoil) [examined].

References based on Global Ant Biodiversity Informatics

 * André E. 1887. Description de quelques fourmis nouvelles ou imparfaitement connues. Rev. Entomol. (Caen) 6: 280-298.
 * André E. 1895. Formicides de l'Ogooué (Congo français). Rev. Entomol. (Caen) 14: 1-5.
 * Bolton B. 1973. The ant genus Polyrhachis F. Smith in the Ethiopian region (Hymenoptera: Formicidae). Bulletin of the British Museum (Natural History). Entomology 28: 283-369.
 * Forel A. 1914. Formicides d'Afrique et d'Amérique nouveaux ou peu connus. Bulletin de la Société Vaudoise des Sciences Naturelles 50: 211-288.
 * Rigato F. 2016. The ant genus Polyrhachis F. Smith in sub-Saharan Africa, with descriptions of ten new species. (Hymenoptera: Formicidae). Zootaxa 4088: 1-50.
 * Wheeler W. M. 1922. Ants of the American Museum Congo expedition. A contribution to the myrmecology of Africa. VIII. A synonymic list of the ants of the Ethiopian region. Bulletin of the American Museum of Natural History 45: 711-1004