Polistes (Polistes) humeralis Polašek, 2023

Polašek, Ozren, 2023, Description of a new species of social wasp from Somalia (Hymenoptera: Vespidae), Zootaxa 5315 (1), pp. 97-100 : 97-99

Polistes (Polistes) humeralis Polašek , sp. nov. ( Figures 1–4 )

Zoobank: 946B21DD-B445-4A0C-8DA0-2362BFAE8DD8

Material examined. Holotype, ♀, pinned (relaxed and re-pinned; the specimen was initially glued to the cardboard, preventing proper morphological examination): „ Somalia, Sar Uanle , X-1972, SBS ( PL) “; depository: MZLS.

Diagnosis. This species is easily separated from all other African members of the genus Polistes by the colour pattern ( Figures 1–4 ). The only other known African species with a yellow or mostly yellow clypeus in females is P. (Polistes) loveridgei Bequaert , easily separated from P. humeralis sp. nov. by the deeper juxtamandibular excavation, substantially lesser amount of yellow and overall smaller body size.

Description. Female. Fore wing length 11.1 mm (body length 14 mm).

Head in frontal view about as long as wide, vertex rounded and comparatively more elevated than in other African Polistes species ( Figure 1 ). Clypeus somewhat wider than long in frontal view ( Figure 1 ), with strongly convex surface in lateral view ( Figure 2 ). Antennal sockets closer to each other than eye margin, interantennal space weakly convex. Gena posteriorly slightly wider than widest part of eye, tempora at thinnest part 0.5x as wide as eye ( Figure 2 ). Clypeus finely punctate in basal half, apical half shiny with larger craters. Gena weakly and sparsely punctate. Entire head covered by short pubescence; setae on frons shorter than forward ocellus diameter. Antennal scape 2.8x as long as its maximum width, 1.2x as long as AF1. AF1 2.7x as long as wide, 1.5x as long as AF2 and AF3 combined. AF2 as long as wide, remaining segments wider than long; AF10 bullet-shaped, about 0.9x as wide as long.

Mesosoma about 1.1x as wide as head ( Figure 3 ). Pronotal carina dorsally with translucent rim, laterally evanescent ( Figure 2 ). Pronotal fovea absent ( Figure 4 ). Mesonotum as long as wide, with weak parapsidal furrows ( Figure 3 ). Mesopleura laterally very weakly punctate with some microstriae; epicnemial carina weak. Scutellum about 2.3x as wide as long, with thin median carina that reaches more than half of its length. Metapleura coarsely punctate and striated. Propodeal surface with moderately developed horizontal striae that are more developed laterally ( Figure 2 ; stronger than in P. loveridgei Bequaert , but weaker than in P. badius Gerstraecker ). Entire thorax covered by short whitish setae similar to those on head.

T1 as wide as long, with perpendicular margin (in lateral view) and evenly convex dorsal surface. Remaining metasomal segments with weak cuticular surface and short whitish pubescence that turns to golden on dorsal surface of T2–T4.

Colour. Ground colour ferruginous. Head frontally mainly yellow; large portion of frons and vertex ferruginous ( Figure 1 ). Mandible, gena and tempora yellow, with yellow colour extending onto posterior surface of head. Pronotum, upper and anterior part of mesopleura yellow ( Figure 3 , 4 ). Mesonotum ferruginous, tegula with yellow mark posteromedially, scutellum and metanotum yellow ( Figure 2, 3 ). Propodeum with two large yellow areas connected with a large yellow area on metapleura ( Figure 3 ). Coxae I yellow, coxae II with medial and lateral yellow patch, coxae III with small lateral yellow patch. Legs ferruginous, anterior surface of femora and tibiae I yellow, tarsi yellowish ( Figure 4 ). Wings translucent, with yellowish colouration towards anterior margin; apical spot weakly developed, light greyish, mainly in marginal cell ( Figure 3 ). Antenna orange dorsally, yellowish ventrally ( Figure 3 ). T1–5 and S1–4 with complete yellow posterior band ( Figure 4 ).

Male. Unknown.

Location. The location points to a research site in south Somalia, about 20 km south of Kismayo. Two more abbreviations from the label suggest that the specimen was collected as part of the Spedizione Biologica in Somalia (“ SBS ”) research programme, which was run by the Centro di Studio per la Faunistica ed Ecologia Tropicali from Florence, Italy. The additional label entry “ PL ” suggests Programma Litorale, and provides the reference to the exact location, which is a thin strip of the coastal area, bordered by the sand dunes on one side and the ocean on the other ( Pardi, 1976).

Etymology. The name comes from the Latin word humerus, “shoulder”, in reference to the lacking pronotal fovea close to humeral angle.

Figures

FIGURES 1–3. Polistes humeralis, sp. nov., female. 1. Head, frontal view. 2. Head, lateral view. 3. Habitus, dorsal view.

FIGURES 4–7. Polistes species. 4. Polistes humeralis sp. nov., female, habitus, lateral view. 5. P. africanus Palisot de Beauvois, female, head and mesosoma, oblique lateral view. 6. P. badius Gerstaecker, female, head and mesosoma, oblique lateral view. 7. P. tenellus du Buysson, male, head and mesosoma, oblique lateral view.