Ropalidia baki Polasek and Onah 2025, sp. nov.
Creators: name: Polašek, Ozren
name: Onah, Ikechukwu
name: Kehinde, Tope
name: Rojo, Veronica
name: Noort, Simon Van
name: Carpenter, James M.
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hymenoptera
Vespidae
Ropalidia
Ropalidia baki

description: Ropalidia baki Polašek and Onah sp. nov.
urn:lsid:zoobank.org:act: 2D001DC3-1974-4379-B6BC-9000A1076D6E
Type specimens. Holotype: Alor Uno, Nigeria, 1♀ (OLM. IKN11). Paratypes: Lamto (Toumodi), Cote d’Ivoire, 2♀♀ (MNHN); Eala, DR Congo, 2♀♀, 1♂ (RMCA); Brazzaville, Republic of the Congo, 1♂ (MNHN). The total number of examined specimens: 5♀♀, 2♂♂.
Diagnosis. A dark species, characterized by reddish markings on mesosoma and metasoma, coarse punctures, short pubescence and specifically punctate male clypeus.
Description. Female.Wing length 8.4–9.2mm (substantially smaller than females of R.tomentosa GERSTAECKER).
Colour. Basal colour dark brown to black, with only handful of yellow markings (Figure 35b). Yellow areas include thin apical line of clypeus, antero-basal spot on mandible, inner orbit and sometimes small yellow area on gena (Figure 35b). Mesosoma and metasoma without yellow markings. Reddish areas elongated spot on tempora, most of mandible, anterior part and inferior angle of pronotum, tegula, occasionally posterior line on scutellum, coxa I and II (sometimes even III), femur and tibia; tarsi black. T1 always reddish or brownish, even in anterior half (Figure 35b). Remaining metasomal segments in basal body colour. Antenna black dorsally, including scape and pedicel; underside sometimes reddish (Figure 35a). Wings transparent or slightly yellowish anteriorly, stigma brown, apical spot brown or grey-brown (Figure 35b).
Head. Clypeus wider than long, convex, with moderately developed juxtamandibular lobes; upes weakly curved, longer than lateral clypeal margin, oculo-clypeal angle very wide (Figure 35a). Clypeus with intermediate-sized shallow punctures at base, apical third with less defined craters. Inner orbit impunctate. Gena slightly narrower than eye, occipital carina well developed, with strong hyaline rim and more sinuate close to mandible base. Anterior half of gena with shallow and large punctures, which diminish towards to few retained punctures near occipital carina. Frons covered by yellowish pubescence and longer protruding setae, equally curved along their entire length (Figure 35a). Ocellar triangle acute forwards. Eyes asetose or covered by very short setae (Figure 35a). Scape about as long as AF1 or slightly shorter, AF2 1.0–1.3 times as long as wide.
Mesosoma. Mesosoma covered by yellowish pubescence and longer protruding setae, equally curved along their entire length (Figure 35a, b). Pronotum and mesonotum with large and shallow punctures. Scutellum elevated centrally, with strongly developed median carina, often with scattered punctures close to its surface. Metanotum coarsely punctate in lateral thirds, centre impunctate; median tooth absent. Metapleuron with few poorly defined punctures anteriorly, almost entirely impunctate elsewhere. Propodeum strongly striate laterally, superior carina weakly developed, not continuing towards inferior propodeal carina and broken down by oblique striae. Propodeal excavation narrowing distally but retaining relatively wide profile, compared to other species (narrower than R. excavata GIORDANI SOIKA and R. salebrosa sp. nov.). Coxa II and III and proximal halves of femur II and III with whitish underlying pubescence and longer protruding setae.
Metasoma. T1 pyriform, shorter (conspicuously shorter than in R. tomentosa GERSTAECKER). T2 shorter, finely punctate. Entire surface of T2 covered by equally curved yellowish setae of intermediate length, which are mostly following its contour and do not stand out as they do in R. tomentosa (GERSTAECKER). T2 lamella brown.
Males. Wing length: 8.7–9.1 mm. Colour. Basal colour dark brown (Figure 71a). Clypeus yellow (Figure 72 aa) or yellow with central black spot (Figure 82a). Mandible entirely yellow, inner orbit and scape merged in yellow, smaller yellow area on gena (Figure 72 aa), coxa I and II complete yellow, coxa III ferruginous; femur I and II with long yellow line, femur III ferruginous (Figure 71a). Antenna black from above, yellow underneath (Figure 71a).
Head. Clypeus slightly wider than long, with projecting apex; basal half covered by large and shallow punctures, apical half impunctate (Figure 72 aa). Scape weakly widened, about as long as AF1, AF2 about 1.2 times as long as wide. Tyloids originate on AF1, terminal three flagellomeres have most of inner surface occupied by matt tyloids (Figure72 bb). Terminal flagellomere elongated, its tip rounded (Figure 82b).
Mesosoma. Tarsal I spur not developed.
Metasoma. Terminal sternum with concave surface.
Male-female pairing strength. High, confirmed by DNA.
Distribution. Cote d’Ivoire, Nigeria, Republic of the Congo.
Etymology. The name originates from the Hausa word for “black”, baki, referring to the general black basal body colour pattern; the name is treated as indeclinable.
Similar species. Both males and females are similar to R. tomentosa (GERSTAECKER), and separation can be challenging across the entire distribution range of R. baki sp. nov. The key criterion for the female separation is the developed antero-basal yellow spot on mandibles in R. baki sp. nov., while females of R. tomentosa (GERSTAECKER) from Western Africa have brownish or reddish mandibles, at most with only a hint of minor yellow antero-basal spot (females of R. tomentosa GERSTAECKER in Eastern Africa often have yellow markings on mandible). Several more features can be useful, including posterior half of gena, which is impunctate or scarcely punctate in R. baki sp. nov., while punctures are commonly retained in R. tomentosa (GERSTAECKER), scarcely punctate mandibular surface, with no more than five punctures in the basal half of mandible, vs always more than five punctures in R. tomentosa (GERSTAECKER), and general pubescence pattern, with frons setae equally bent along entire length, while in R. tomentosa (GERSTAECKER) setae are straight with bent distal quarter. Separation of males is less complicated, as R. baki sp. nov. males have completely impunctate apical half of clypeus. Interestingly, males of both species can have a central black spot on clypeus, which is uncommon in most African species. Additionally, there may be some confusion with R. excavata GIORDANI SOIKA; the scutellum is elevated with strong median carina in R. baki sp. nov., as opposed to flattened in R. excavata GIORDANI SOIKA.
Genetics. One specimen was genotyped, and the genetic sequence of the second one was obtained from another study; both show a relatively low level of diversity and seem to be in a sister position with R. fita sp. nov. and R. unidentata GIORDANI SOIKA. The corresponding BIN assignment is BOLD:AEA6543.
description: Published as part of Polašek, Ozren, Onah, Ikechukwu, Kehinde, Tope, Rojo, Veronica, Noort, Simon Van & Carpenter, James M., 2025, Revision of the mainland African species of the Old World social wasp genus Ropalidia Guérin-Méneville 1831 (Hymenoptera; Vespidae), pp. 1-142 in Zootaxa 5626 (1) on pages 68-70, DOI: 10.11646/zootaxa.5626.1.1, http://zenodo.org/record/15325272