Polyrhachis submarginata

Nothing is known about the biology of .

Identification
Rigato (2016) - A relatively large species in the revoili-group, with somewhat slender head and appendages, incomplete and weak pronotal margination, and very weak propodeal ridges.

Polyrhachis submarginata is characterised by weak pronotal margination and propodeal ridges, and a relatively high SI. Polyrhachis submarginata is similar to Polyrhachis otleti and the main differences between them are reported in the key. Polyrhachis submarginata seems to link revoili-group species with immarginate mesosoma and with well defined, although incomplete, margination. Polyrhachis volkarti Forel is similar but is smaller, has a usually immarginate pronotum, distinctly more slender mesosoma. Well developed propodeal ridges, and a higher SI.

Polyrhachis kohli, P. submarginata and P. volkarti look very similar, and share some important features: 1) a shallow clypeal lobe; 2) relatively long scapes, SI > 150; 3) abundant pilosity on body and appendages; 4) mesosoma completely immarginate or almost so; 5) propodeal dorsum and declivity separated by a pair of small, more or less developed, ridges; 6) petiole armed with a pair of moderately long median spines and a pair of lateral much shorter teeth; 7) rough, mostly irregularly longitudinal rugulose sculpturation on head and mesosoma; 8) Body coated with abundant, relatively short and moderately dense greyish pubescence never hiding the sculpturation.

The main differences can be summarized as follows:

Distribution based on Regional Taxon Lists
Afrotropical Region: Central African Republic.

Nomenclature

 *  submarginata. Polyrhachis submarginata Rigato, 2016: 39, figs. 12a-c (w.) CENTRAL AFRICAN REPUBLIC.

Worker
Holotype. HL 1.66, HW 1.25, CI 75, SL 2.02, SI 162, FW 0.45, FI 36, PW 1.13, WL 2.17, HTL 1.98.

Clypeus medially subcarinate and with anterior margin bearing a protruding rectangular lobe, whose lateral corners are right angled. Head in full face view moderately elongate, oval, wider behind than in front, posterior margin widely convex. Eyes moderately large and convex. Mesosoma stout and evenly convex in profile. In dorsal view pro- and mesonotum distinctly transverse; propodeal dorsum somewhat longer than wide. Pronotum laterally weakly marginate and armed with two small diverging teeth; the margination incomplete and somewhat difficult to see even because of sculpturation and pubescence. Mesonotum and propodeum immarginate. Propodeal dorsum with two faint posterolateral ridges at its posterior corners, medially propodeal dorsum and declivity confluent in a blunt curvature. Promesonotal suture slightly impressed, metanotal suture faint. Petiole with a dorsal pair of widely separated, moderately long and diverging spines and a pair of lateral sharp teeth; the space between dorsal spines straight. First gastral tergite anteriorly weakly concave.

Mandibles faintly longitudinally striolate and with sparse piligerous pits, mostly shining. The whole body and appendages finely reticulate-punctate. Body opaque, appendages weakly shining. Head and mesosomal dorsum with a superimposed, fine, irregular longitudinal rugulation.

Standing hairs abundant everywhere and longer on head and mesosoma. Hairs on scapes at most a little longer than scape diameter at midlength; hairs on tibiae at most about as long as half the maximum tibial width. Body and appendages coated with dense, short and silvery to slightly golden pubescence, not masking the sculpturation and longer on mesosoma and petiole.

Colour black, most of the funicular joints and mandibular apices ferrugineous.

Paratype. HL 1.62, HW 1.22, CI 75, SL 1.98, SI 162, FW 0.47, FI 39, PW 1.19, WL 2.3, HTL 1.98. All main features as in the holotype.

Type Material
Holotype. CENTRAL AFRICAN REPUBLIC: Res. Dzanga–Sangha, 12.7 km, 326° NW Bayanga, 3°00.27’ N 16°11.55’ E, 420 m, 10–11.v.2001 (S. van Noort) (: CASENT0087089 CAR01-M78). Paratype. CENTRAL AFRICAN REPUBLIC: same data as the holotype, except 14–15.v.2001 (S. van Noort) (1 w, CASC: CASENT0088752 CAR01-M123).

References based on Global Ant Biodiversity Informatics

 * 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.