Ropalidia nigrocerasina Polašek, 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 : 105-106

publication ID	https://doi.org/10.11646/zootaxa.5626.1.1
publication LSID	lsid:zoobank.org:pub:42F5F55D-041C-4CEE-A106-2927C5BDF2AA
DOI	https://doi.org/10.5281/zenodo.15325256
persistent identifier	https://treatment.plazi.org/id/4F5987BA-E800-FFDE-FF11-FB1C74C49A06
treatment provided by	Plazi
scientific name	Ropalidia nigrocerasina Polašek
status	sp. nov.

Treatment

Ropalidia nigrocerasina Polašek sp. nov.

urn:lsid:zoobank.org:act:9D44FDDC-A3BC-4E54-A7ED-2008C32D102D

Type specimens. Holotype: Abercorn (Mbala), Zambia, 1♂ ( MSNV.101) . Paratypes: 1 ♀ and 3♂♂ with the same collection data as the holotype ( MSNV); Tenke , Katanga DR Congo , 1♀ ( NHM); Katanga , DR Congo , 1♀ ( MSNV); Mwinilunga , 50 km E, Zambia , 1♀ ( OLM); Kanzenze , DR Congo , 1♀ ( RMCA); Khombe , Malawi , 1♀ ( RMCA). The total number of examined specimens : 6♂♂, 4♀♀.

Diagnosis. Member of capensis -group, characterized by black mesosoma underside, black coxa, upwardly directed setae in propodeal excavation, punctate pronotal collar and short pubescence high on tempora. Males darker, with coarsely punctate clypeus base, tyloids originating from AF(4)5, developed tyloid on terminal flagellomere and yellowish wings.

Description. Females. Wing length 5.9–6.6 mm. Colour. Basic colour dark brown with dark reddish markings, commonly without any yellow markings on mesosoma and metasoma ( Figure 4 View FIGURE 4 aa). Clypeus yellow with large basal brown or dark brown-black spot attached to base ( Figure 12b View FIGURE 12 ; one examined specimen has completely brown clypeus). Inner orbit with thin yellow line, interantennal area with smaller yellow patch or completely without yellow markings ( Figure 12b View FIGURE 12 ). Mandible yellow with complete median brown band ( Figure 99 View FIGURE 99 ). Gena and tempora reddish-brown, vertex black ( Figure 12b View FIGURE 12 ). Mesosoma and metasoma without yellow markings ( Figure 4 View FIGURE 4 aa). Pronotum, scutellum and metanotum reddish, mesonotum and propodeum black (in one specimen with bilateral reddish spot), mesopleuron black ( Figure 4 View FIGURE 4 aa), sometimes with a small reddish area. Mesosoma underside black, coxa and proximal part of femur black, distal part of femur, tibia and tarsi ferruginous-brown; terminal tarsal segment equally coloured tibia ( Figure 4 View FIGURE 4 aa). T1 reddish, T2 and S2 with posterior reddish band ( Figure 4 View FIGURE 4 aa). Wings transparent, anterioly yellowish; apical spot faintly yellowish ( Figure 4 View FIGURE 4 aa). Stigma lightly brown or yellowish. Antenna basally brown, flagellomeres blackened dorsally, ventrally black or yellow-orange near tip ( Figure 12b View FIGURE 12 ).

Head. Morphologically not substantially different from R. valentula sp. nov.; clypeus about as wide as long, upes straight or slightly curved, juxtamandibular lobe well developed, apex moderately protruding ( Figure 12b View FIGURE 12 ). Clypeus base with occasional and poorly defined puncture. Frons and tempora with larger and shallow punctures. Eyes covered by short setae or entirely asetose ( Figure 12b, b View FIGURE 12 ). Frons covered by protruding setae that are about 0.7–0.8 times as long as ocellus diameter ( Figure 12a View FIGURE 12 ), as opposed to longer setae in R. valentula sp. nov. and R. retromaculata sp. nov. Setae on gena and tempora of similar length (as opposed to longer setae on tempora in R. valentula sp. nov. and R. retromaculata sp. nov.). Ocelli with substantially broader base than sides. Mandible wider proximally than distally. Scape longer than AF1, AF2 about as long as broad or somewhat broader ( Figure 12b View FIGURE 12 ).

Mesosoma. Mesosoma covered by denser silvery-whitish pubescence ( Figure 12a View FIGURE 12 ); pubescence on mesonotum can be somewhat yellowish. Punctures on mesosoma large; mesonotum sparsely and shallowly punctate, median suture and parapsidal furrows less developed. Pronotal collar punctate in ventral half ( Figure 12a View FIGURE 12 ), as opposed to impunctate in R. valentula sp. nov. and R. retromaculata sp. nov. Scutellum without median carina. Propodeum similar to other members of capensis -group.

Metasoma. T1 pyriform, somewhat broader than in R. retromaculata sp. nov., but narrower than R. valentula sp. nov. T2 of intermediate length, with shorter section with parallel margins. T2 lamella with shallow T2/S2 nick ( Figure 12a View FIGURE 12 ). T2 with intermediate and shallow, poorly defined punctures, S2 with more defined punctures, distal part directionally punctate.

Males resemble females in general, with more yellow ( Figure 54a View FIGURE 54 ). Wing length 5.8–6.3 mm. Colour. Clypeus yellow with smaller or intermediate-sized brown or blackish basal area ( Figure 54b View FIGURE 54 ). Mandible yellow with large triangular basal black spot (about twice larger than that in R. valentula sp. nov. males), small yellow spot on gena, interantennal area and inner orbit with yellow areas ( Figure 54b View FIGURE 54 ). Mesosoma and metasoma without yellow markings, with black and red skipping pattern: pronotum, scutellum, and metanotum reddish, mesonotum, mesopleuron, metapleuron and propodeum black ( Figure 54a View FIGURE 54 ). Metasomal segments brown, sometimes with suffused posterior reddish band, terminal three segments often more lightly coloured ( Figure 54a View FIGURE 54 ). Antenna variably coloured; scape ferruginous (with ferruginous or yellow colour underneath), AF1 ferruginous or proximally ferruginous and distally black, remaining segments ferruginous, darkened or black from above, ferruginous or orange underneath ( Figure 54a View FIGURE 54 ). Coxa brown or dark brown, femur usually brown (proximally black in specimens with black coxa), tibia and tarsi brown ( Figure 54a View FIGURE 54 ).

Head. Clypeus substantially wider than long (1.1–1.3 times as wide as long; Figure 54b View FIGURE 54 ), unlike R. valentula sp. nov., whose males have clypeus about as long as wide. Upes slightly curved, OCA visible but weak, apex depressed inwards, tip acute ( Figure 54b View FIGURE 54 ). Clypeus with intermediate and poorly defined punctures basally, centre and area towards apex with dissipating craters or almost impunctate. Inner orbit impunctate, frons and vertex with well-defined punctures. Gena broad, about 0.8–1.1 times as wide as eye ( Figure 54a View FIGURE 54 ). Mandible robust, with wide base and tortuous excavation, similar to R. valentula sp. nov. Scape not substantially widened, about as long or somewhat longer than AF1, AF2 as long as wide or slightly wider ( Figure 54b View FIGURE 54 ). Tyloids less developed, symmetrical in proximal-distal direction ( Figure 54c View FIGURE 54 ). Tyloids originate on AF(4)5 ( Figure 99b View FIGURE 99 ). Terminal flagellomere acute, with developed tyloid that reaches the very tip ( Figure 54c View FIGURE 54 ).

Mesosoma. Fore tarsal spur I weak.

Metasoma. S7 flattened.

Male-female pairing strength: excellent; type series specimens originate from the same nest (labelled as nest 1462). Notably, this species has a very high share of examined males, with as much as 42% of all examined specimens.

Distribution. Zambia, DR Congo, Malawi.

Etymology. The name is based on the Latin nigro -ra -rum (“to be black”) and cerasinus -a -um (cherrycoloured), and refers to the black and reddish body of this species.

Similar species. R. valentula sp. nov. and R. retromaculata sp. nov.; separating criteria are provided in the key to species. Females can sometimes resemble R. acuminata sp. nov., with the shape of clypeus providing sufficient determination feature. Males resemble R. valentula sp. nov., but they are easily separated by the criteria in the key to species.

Genetics. The group of the three similar species ( R. valentula sp. nov., R. retromaculata sp. nov. and R. nigrocerasina sp. nov.) was initially considered a colour variation of the same species. However, after the completion of genetic analysis and after the males of R. nigrocerasina sp. nov. were identified, it became evident that they are morphologically separate from R. valentula sp. nov. Based on the genetic distance of these three groups, all were elevated to the species level. The genetics of R. nigrocerasina sp. nov. suggests a nested position within the R. valentula sp. nov. lineages, while R. retromaculata sp. nov. seems to be a sister group to both of these species. R. nigrocerasina sp. nov. was assigned a single BIN, BOLD: ADN 6541.