Ropalidia africana ( CAMERON 1910 ), 2025

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), Zootaxa 5626 (1), pp. 1-142 : 62-63

Ropalidia africana ( CAMERON 1910) stat. rev.

Icaria africana CAMERON 1910

Type material. Two females in the NHRS collection, labelled as NHRS-HEVA 000007511 (holotype) and NHRS-HEVA 000007512 (paratype; photographs examined; notably, both specimens have the additional small red labels “37” [printed] and “75” [hand-written] in the following line on the holotype, and “38” and “75” in paratype). Unfortunately, the species description ( Cameron, 1910) does not provide a good account of the specimens; the pterostigma and nervature colour disagree (suggesting that both are black, while the examined photos show that both are brown).Additionally, the key to species in the paper is flawed, suggesting that this species has developed scutellar carina (in the species description) or that it is not developed (the key to species on the same page). Unfortunately, Cameron focused on metasoma’s colour and shape in his paper ( Cameron, 1910). This was already challenged by Bequaert, who stated that the shape of T 1 is of “little practical use due to extensive degree of variation, even within the same colony ” ( Bequaret, 1918), and by Meade-Waldo, who claimed that Cameron was “evidently misled by the fact that the metasomas of his two types hang at different angles from the median segment ” (Meade-Waldo, 1913).

Another two specimens from the expedition were recovered during this revision in the NHM, with similar labels but indicating different altitudes above the sea level (the holotype suggests 1000–1200 m, paratype 1000–1300 m, while the two more specimens originate from 1000–1200 m and 1300–1900 m) .

Comments. This is a very variable species, with numerous morphological and colour combinations that were recorded in the examined specimens. The general description of this species is based on a very shallow propodeal excavation that is usually covered by weakly developed and fine striae, the variably developed propodeal carina, the almost impunctate metapleuron and elongated T1 (which has posterior constriction). The female clypeus shape is usually pentagonal, although even the type series specimens show a substantial degree of shape variation; the clypeus can be pentagonal with OCA nearly missing or broader, with curved upes and a strongly projecting apex. The pronotum colour is a helpful determination feature; most specimens have a complete yellow line underneath the pronotal carina, extending onto the postero-inferior pronotal margin ( Figure 31c ). In addition, the type specimens and most of the examined females have yellow markings on coxa II and III, which are uncommon in females of other species. These markings commonly originate on the lateral margin; coxa II and II may be completely yellow (in one examined specimen) or without yellow markings (in two examined specimens). An additional helpful feature is the elongated T1, similar to R. amanhii sp. nov. ( Figure 31b ). The most diverse, and in this sense, the most problematic feature is the antenna colour: the type series specimens all have the antenna ferruginous, while all other examined females have the antenna darkened or even black dorsally.

Males of this species are described here for the first time.

Material. Diani Beach , Kenya, 1♂ ( SNM); Baraka, DR Congo, 1♂ ( NHM); Deti, DR Congo, 1♂ ( NHM); Ikelenge, Zambia, 1♂ ( NHM); Muheza, Tanzania, 1♂ ( SNM). The total number of examined specimens: 5♂♂ .

Diagnosis. Males of this species are characterized by a shallow propodeal excavation, rounded terminal flagellomere and somewhat elongated antenna.

Description. Males. Wing length 8.6–10.1 mm. Colour. Basal colour dark brown. Clypeus yellow, inner orbit, interantennal area and lower part of eye sinus yellow, gena with small elongated yellow spot ( Figure 70a ). Mandible yellow, with minor brownish triangular area; frons brown, area around ocelli dark brown or black ( Figure 70a ). Mesosoma dark brown with variable reddish and yellow areas. Yellow areas include thin line underneath pronotal carina, anterior surface of mesopleuron, coxa I and II, femur I and II with irregular yellow patches, femur III often with reddish markings; tibia brown, tarsi brown or dark brown. Reddish areas of mesosoma may include mesopleuron, scutellum and metanotum. T1 without posterior yellow band, T2 with thin yellow band extending to thinner yellow band on S2; remaining metasomal segment equal to the basal body colour or darker. Antenna darkened or black dorsally, brown or yellowish underneath ( Figure 70a ). Fore wing apical spot brown to dark brown, wings mostly transparent or slightly yellowish in some specimens.

Head. Clypeus convex, wider than long, with curved upes and no OCA; apex subacute, slightly projecting, lateral margins angled ( Figure 70a ). Basal half sparsely and weakly punctate and covered by fine silvery setae of equal length basally and apically. Mandible matt with occasional puncture. Gena and tempora weakly punctate with more than half of posterior surface impunctate. Gena about 0.6–0.8 times as wide as eye. Frons weakly and shallowly punctate, with gradually diminishing punctures definition towards occipital carina. Ocellar triangle acute forward. AF1 longer than scape (about 1.2–1.4 times), AF2 about 1.8–2.1 times as long as wide. Tyloids flat and matt or slightly shiny, originate on AF1. Terminal flagellomere elongated and curved ( Figure 70b ).

Mesosoma. Pronotum and mesonotum with large, defined and coarse punctures, most coarsely developed on scutellum. Metapleuron impunctate or with only few poorly defined punctures.

Metasoma. Terminal sternum flattened or weakly concave.

Male-female pairing strength: low. Pairing is based on the propodeal features and similarity of the clypeal shape (however, males were not successfully genotyped, nor were there any nest series that would provide stronger pairing strength). The closest genetic link is a male in a separate BIN from the rest of the females (although this is the closest possible match in terms of genetic distances).

Similar species. Some confusion is possible with R. tenuipilosa sp. nov. (males of that species do not have a developed median scutellar carina) and R. aethiopica (DU BUYSSON) , especially in specimens of that species that have less developed propodeal striations.

Taxonomic status. This taxon has been the most commonly synonymized of all African Ropalidia species. It was suggested as a synonym of R. distigma GERSTAECKER (= R. puncta FABRICIUS ) (Meade-Waldo, 1913), R. cincta (LEPELETIER) with black pterostigma ( von Schulthess-Rechberg, 1913), leading Bequaert to consider it as a very doubtful species, suggesting that this was a possible synonym of R. aethiopica (DU BUYSSON) ( Bequaret, 1918) . The confusion is caused by varying morphological features of the examined specimens. However, the combination of morphological features and genetic analysis was considered sufficient for re-establishing this taxon at the species level. The male’s identity remains somewhat questionable, as the only genetically confirmed male belongs to a separate BIN cluster (see under Genetics). The extent of phenotypic and genetic differences from other species was considered sufficient to restore the status of this taxon and consider it as a species.

Distribution. Gabon to Mozambique.

Genetics. Five specimens were successfully genotyped, belonging to three BINs; a single male from Zambia (BOLD:ADR2417), a female from Kenya, in the same cluster with R. mangoflava sp. nov. (BOLD:ACK8399), while the remaining specimens were clustered into the third cluster, distributed in Kenya, Malawi and Mozambique (BOLD:ADM2240). The analysis of the COI gene suggested proximity to R. tomentosa (GERSTAECKER) and the Asian-Australian cluster of species. 28s rDNA confirmed homogenous and specific clustering, with sequence shared only with R. mangoflava sp. nov.

Figures

FIGURE 31. Ropalidia species, females. a–c. R. africana (CAMERON) stat. rev.. a. propodeum, b. T1, dorsal view, c. pronotum and head, lateral view, aa–cc. R. aethiopica (DU BUYSSON), propodeum. aa. from Ghana. bb. from Kenya. cc. from Zanzibar.

FIGURE 70. Ropalidia africana (CAMERON) stat. rev., male. a. head. b. distal flagellomeres.