Polyrhachis luteipes, Rigato, Fabrizio, 2016

Rigato, Fabrizio, 2016, The ant genus Polyrhachis F. Smith in sub-Saharan Africa, with descriptions of ten new species. (Hymenoptera: Formicidae), Zootaxa 4088 (1) : 30-31

Polyrhachis luteipes n. sp.

( Figures 9 a–c)

Diagnosis. A small, thickset species in the revoili -group, with a lobed clypeal margin, minute pronotal teeth, a virtually unarmed propodeum, shining integument and testaceous legs.

Holotype worker. HL 1.09, HW 0.90, CI 83, SL 1.30, SI 144, FW 0.34, FI 38, PW 0.68, WL 1.40, HTL 1.16.

Clypeus ecarinate and with its anterior margin bearing a distinct protruding rectangular lobe, whose lateral corners are right-angled. Head in full face view oval, wider behind than in front, posteriorly widely convex. Eyes moderately large and convex. Mesosoma evenly convex in profile and immarginate. Pronotal humeri armed with two minute, diverging teeth. Propodeal dorsum with two faint ridges at its posterior corners. Propodeal dorsum and declivity confluent and forming a blunt obtuse angle in profile. Promesonotal suture clearly visible, metanotal suture faint. Petiole with a dorsal pair of moderately long and diverging spines and a pair of lateral sharp teeth; the space between dorsal spines straight. First gastral tergite anteriorly concave.

Mandibles at most superficially shagreened/striolate with sparse piligerous pits. The whole body mostly superficially reticulate, shining.

Standing hairs thin and pale, moderately abundant on body and appendages, relatively long especially on the head; longest hairs on scapes about four times as long as scape diameter at midlength. Longest standing hairs on tibiae about as long as maximum tibial width. Pubescence moderately long and sparse on the head, longer and fairly dense on the mesosoma, short and fairly sparse on the gaster.

Body and coxae black, mandibles, antennae and legs mostly testaceous; forefemurs mostly brown.

Paratype workers (n=2). HL 1.22, HW 0.98–1.00, CI 80–82, SL 1.47–1.49, SI 147–152, FW 0.40–0.41, FI 41, PW 0.85, WL 1.57–1.59, HTL 1.32–1.36.

They mostly differ from the holotype by their completely unarmed propodeum, without any trace of teeth or ridges. Moreover, scape and first funicular joint mostly brown.

Holotype. CAMEROUN: Mbalmayo, xi.1993 (N. Stork) (BMNH, specimen tagged: “F.93.6/1”).

Paratypes. CAMEROUN: Minko Meyos, 15 S of Yaoundé, iii.1997, mango (J.L. Mercier) (2 w, BMNH).

Comment. Polyrhachis luteipes shows a variable development of propodeal ridges, as well as P. dubia and, maybe, P. longiseta . Polyrhachis luteipes is similar to P. khepra , which is slightly larger, lacks an evident promesonotal suture, is more hairy, has a more sculptured head and darker appendages.

Figures

FIGURE 9. Polyrhachis luteipes, holotype worker: A, body profile; B, dorsum of mesosoma; C, head in full-face view. (Photos by M. Zilioli)