Ropalidia excavata GIORDANI SOIKA 1977

Ropalidia excavata GIORDANI SOIKA 1977 View in CoL

Type material. In contrast to the species description, the examined holotype and one more paratype are males, very likely diploid males (Supplementary Figures 8 View FIGURE 8 and 9). Nevertheless, the species-defining features are visible on the holotype, therefore, we retained its status.

Comments. A dark species with deep juxtamandibular excavations in females ( Figure 22 View FIGURE 22 bb), and a characteristic quadratic shape of propodeal excavation, covered by very fine striae ( Figure 19 View FIGURE 19 bb). In contrast to R. salebrosa sp. nov., R. excavata GIORDANI SOIKA has pyriform and posteriorly punctate T1, which is comparatively wider distally than most mainland African Ropalidia species ( Figure 22 View FIGURE 22 aa). Notably, the comparison of the type series with other examined specimens suggested a somewhat variable group in terms of clypeus morphology in females (ranging from very deep and developed juxtamandibular excavations to moderately developed), varying densities of forewing trichomes and, finally, even varying shape of T1. Males are described here for the first time.

Males.

Material examined. La Maboke, Central African Republic, 1♂ ( MNHN.22) .

Diagnosis. The defining characteristics of this species include wide and finely striate propodeal excavation, developed inferior carina, heavy wings trichome, coarsely punctate dorsal parts of mesosoma and obtuse terminal flagellomere in males.

Description. Wing length 7.8 mm. Colour. Basal colour dark brown to black ( Figure 89a View FIGURE 89 ). Clypeus, inner orbit, interantennal area and lower part of eye sinus yellow ( Figure 64a View FIGURE 64 ). Mandible yellow, gena lightly brown-reddish, tempora, frons and vertex dark brown to blackish ( Figure 64a View FIGURE 64 ). Mesosoma dark brown, except following yellow areas: thin line underneath pronotal carina, anterior mesopleuron, coxa I–III; femora with diminishing size of anterior yellow patch; tibia light brown, tarsi darker to almost black; faint reddish-yellowish median posterior spot on metanotum ( Figure 89a View FIGURE 89 ). Wings yellowish, nervature brown, apical spot light brown, stigma dark brown; trichome very dense ( Figure 89a View FIGURE 89 ). Metasomal segments without yellow markings, T1 with posterior reddish band, T3–7 and S3–7 ferruginous ( Figure 89a View FIGURE 89 ).

Head. Clypeus mildly convex, juxtamandibular lobe weak, apex subacute, lateral sides more or less parallel, upes evenly curved ( Figure 64a View FIGURE 64 ). Basal half of clypeus sparsely and coarsely punctate. Entire clypeus covered by fine silvery setae of similar length basally and apically. Base of mandibles matt, with occasional poorly developed puncture. Gena and tempora punctate, punctures gradually shallowing close to occipital carina. Frons desnely punctate, punctures less than a radius apart. Ocellar triangle acute forward. AF1 longer than scape, AF2 about 1.6 times as long as wide. Tyloids hardly discernible; careful inspection reveals traces on AF1–AF3, those on AF4 conspicuous, flat and matt. Terminal flagellomere slightly elongated, flattened, tip rounded ( Figure 64b View FIGURE 64 ).

Mesosoma. Pronotum and mesonotum with large, defined and coarse punctures; scutellum flattened, median carina not developed. Setae on propodeal excavation very fine ( Figure 19 View FIGURE 19 bb), as opposed to R. baki sp. nov. and R. kuficha sp. nov., which have longer and more developed setae ( Figure 43a View FIGURE 43 ).

Metasoma. S7 weakly concave.

Male-female pairing strength: high; based on the similarity of the only examined specimen to a paratype; in addition, defining features include the morphology of scutellum, propodeal excavation and wing similarities.

Distribution. Species description and type series provide the initial distribution information ( Giordani Soika, 1977), while a subsequent paper refers to newly described R. kuficha sp. nov. (Henshaw, Woller-Skar, & Pence, 2014), based on the examined specimens from AMNH and NMK. The distribution range includes Cameroon, Gabon, Central African Republic, Republic of the Congo, DR Congo and one specimen from Cote d’Ivoire (the last specimen has more striated propodeal excavation and more brownish overall appearance; in the absence of further specimens and more evidence, here we consider it to be an odd specimen of this species).

Similar species. Morphologically closest species is R. salebrosa sp. nov., which is easily separated by the T1 and S1 morphology. There can be some problems in separation from R. baki sp. nov. females; in these cases, the defining criteria include entirely black or brown tempora, inferior pronotal angle and the dorsal surface of T1 (reddish in R. baki sp. nov.), black coxa I with an apical yellow spot in (entirely reddish in R. baki sp. nov. females), and punctate inner orbit (impunctate in R. baki sp. nov.). Females of R. kuficha sp. nov. can be separated based on the propodeal excavation, which is broad, finely striated and covered by very fine pubescence in R. excavata GIORDANI SOIKA , in contrast to distally narrowing propodeal excavation, covered by stronger striae and longer setae in R. kuficha sp. nov. Other useful features include broader and more globular T1, which is about 0.5–0.6 times as wide as T2 (more slender in R. kuficha sp. nov., about 0.4 times as wide as T2) and coxa I with yellow markings originating from the ventral tip (lateral margin in R. kuficha sp. nov.). In addition, R. excavata GIORDANI SOIKA has weak or undeveloped median scutellar carina, which is more developed in both R. baki sp. nov. and R. kuficha sp. nov. Some problems may arise in separating the d cluster of R. guttatipennis (DE SAUSSURE) , prevalent in Cameroun and Gabon; this suggests that these two species possibly occupy similar ecological niches, with strong selection pressure towards darker basal body colour. The defining features, in this case, include the shape of clypeus, with stronger juxtamandibular excavations ( Figure 22 View FIGURE 22 bb, Figure 64a View FIGURE 64 ), the shape of T1 ( Figure 22 View FIGURE 22 aa), and the shape of scutellum, which is flattened and without median carina in R. excavata GIORDANI SOIKA ( Figure 19 View FIGURE 19 bb), while it is rounded with developed median carina in R. guttatipennis (DE SAUSSURE) .

Genetics. All of the examined specimens were older than 30 years.