Afrepsilon Selis & Carpenter, 2024, gen. nov.
Creators: name: Selis, Marco
name: Carpenter, James M.
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hymenoptera
Vespidae
Afrepsilon

description: Genus Afrepsilon gen. nov.
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Fig. 21
Type species
Afrepsilon ferrugineoaureum gen. et sp. nov.
Etymology
The genus name is derived from the combination of ‘Afro’ and ‘ Epsilon ’. The first comes from the Latin adjective ‘ afer, afra, afrum ’ (= ‘African’), referring to the distribution of the genus, while the second refers to the similarity to the Indo-Australian genus Epsilon de Saussure, 1855.
Diagnosis
Distinguished from other Afrotropical genera of Eumeninae by the following combination of characters: head markedly transverse; clypeus apically emarginate and lacking longitudinal carinae, apical margin about as wide as interantennal distance (Fig. 21A); mandible long and narrow with five teeth, apical teeth about as long as basally wide, fifth tooth small and almost completely fused with fourth in single cutting edge, basal smooth part of mandible longer than apical dentate part (Fig. 21B); palpal formula 6:4, labial palpi short and robust and densely setose, first segment of labial palpi robust and strongly expanding and third segment with thick subapical seta (Fig. 21D); vertex short, 1.2–1.4 × as long as distance between ocellus and eye, with sharp occipital carina, cephalic foveae of female placed in a barely depressed area (except A. pictum) (Fig. 21C); gena narrow, shorter than dorsal lobe of eye in dorsal view, and more or less parallel-sided in lateral view, strongly crenate along occipital carina in male (Fig. 21E); anterior face of pronotum smooth and without pits or foveae, pronotal carina forming even curve on humeri; epicnemial carina distinct but dull; metanotum not carinate and evenly sloping from scutellum to propodeum (Fig. 21F); tegula with short posterior lobe not equaling parategula, axillary fossa small and oval; prestigma shorter than half pterostigma, second submarginal cell sessile and with acute basal angle, second recurrent vein interstitial (Fig. 21G); propodeum short and not extended behind metanotum, dorsal faces placed below level of rest of mesosoma, propodeum without dorsal and lateral carinae (with weak dorsal carina in A. pictum), submarginal carina weakly developed above valvula and completely fused with it, posterior face of propodeum with long longitudinal carina connected to basal depressed subtriangular sclerite (Fig. 21F); metasoma sessile; T1 not carinate and with short hyaline apical margin; apical margin of T2 shortly translucent and with transverse lamellar ridge along basal margin of translucent part, appearing duplicate (Fig. 21H); aedeagus apically bifid and with very large ventral lobes sharply separated from rest of base (Fig. 27P–Q).
Differential diagnosis
The new genus is morphologically similar to the Indo-Australian genus Epsilon de Saussure, 1855, but differs in the following aspects [characters of Epsilon in brackets]: male F11 finger-shaped with rounded apex and long [subtriangular with pointed apex and very short], mesosoma weakly elongate [short and robust, squat-bodied], posterior lobe of tegula blunt and not equaling parategula [sharply pointed and equaling parategula], parategulae narrow and curved or straight [wide and angled], epicnemial carina exceeding epipleural suture above and disappearing on mesosternum below [not exceeding epipleural suture above and touching contralateral carina on mid-line of mesosternum], basal triangular sclerite of propodeum depressed [flattened with two lateral pits], submarginal carina barely produced above valvula [forming a rounded lobe above valvula], S2 normally convex in middle of the base [depressed in middle of the base].
Following the key written by Gusenleitner and published in Carpenter et al. (2009), it is difficult to correctly place the genus Afrepsilon gen. nov.
Couplet 1 divides the genera with the second recurrent vein interstitial or received in the third submarginal cell from those with the vein received in the second submarginal cell. Afrepsilon gen. nov., having the interstitial second recurrent vein, would fall into the first group, which however in the key includes only the genera attributed to the so-called “Raphiglossini”, a group well characterized and clearly distinguished from Afrepsilon for numerous characters (e.g., antenna of the male not modified at apex, second submarginal cell obtuse at the base, strongly elongated mouthparts in Raphiglossa Saunders and Elisella Giordani Soika). The interstitial second recurrent vein is actually also found in various other genera of Eumeninae, such as some species of Alastor Lepeletier, or in the genus Epsilon outside of the African fauna; the position of the vein therefore cannot be used as the sole diagnostic character and Afrepsilon runs to couplet 4.
Couplet 45 distinguishes Eumeninae with a translucent apical margin on T1 (Euodynerus Dalla Torre, 1904 and related genera) from those with a non-translucent margin. Afrepsilon gen. nov. has a differentiated apical margin, which appears very thin, almost hyaline and separated from the rest of the tergite by a shallow step, while in Euodynerus and related genera the apical margin is clearly more developed, translucent and in continuity with the rest of the tergite. Afrepsilon then runs to couplet 54.
At couplet 58, Afrepsilon gen. nov. corresponds to the second choice due to the prestigma being shorter than half of the pterostigma, but the character relating to the axillary fossa could leave some doubts. The couplet distinguishes between slit-like fossa and rounded fossa but does not take into account the genera with an intermediate morphology, consisting of a very narrow oval pit. This is one of the weakest and least reliable characters of the key, as there are numerous exceptions that do not allow the couplet to be used adequately (e.g., some Antodynerus have a significantly narrower pit than some Rhynchium Spinola, 1806). In any case, Afrepsilon runs to couplet 69, showing no affinity with the genera considered to have a “slit-like” fossa.
The blunt epicnemial carina in Afrepsilon gen. nov. could cast doubt at couplet 78, which distinguishes a genus without epicnemial carina, Postepipona Giordani Soika, 1974, from those with the carina. The examination of the type species of Postepipona, P. socotrae Giordani Soika, 1974, has actually shown that the epicnemial carina is present, although very short and weak. However, this does not pose problems, as Postepipona is a junior synonym of Antepipona de Saussure, 1855 (this synonymy will be treated in more depth in another paper), a genus immediately distinguished from Afrepsilon by numerous characters, including the submarginal carina of the propodeum forming a pointed lobe above the propodeal valvula and the narrow and posteriorly pointed tegula.
Finally, Afrepsilon gen. nov. runs to couplet 81, the last of the key, in which the genera Allepipona Giordani Soika, 1987 and Stellepipona Giordani Soika, 1973 are distinguished, on the basis of the morphology of the metanotum. Afrepsilon is immediately distinguished from both genera by numerous characters, among which the most evident are the gena (very narrow in Afrepsilon, wide in Allepipona and Stellepipona), the metanotum (sloping in Afrepsilon, almost vertical in Allepipona), the axillary fossa (smaller than an ocellus and with strongly widened lateral lamella in Afrepsilon, larger than an ocellus and with moderately widened lamella in Stellepipona, as large as the antennal torulus and with thin lamella in Allepipona), the tegula (short and wide with blunt posterior lobe in Afrepsilon, long and narrow with variably acute lobe in Allepipona and Stellepipona), the dorsal faces of propodeum (almost at same level as metanotum and strongly bordered posteriorly in Afrepsilon, well below level of metanotum and smoothly passing into posterior face in Allepipona and Stellepipona) and the submarginal carina of the propodeum (barely developed in Afrepsilon, forming a short but clearly evident lobe in Allepipona).
It is evident that Afrepsilon gen. nov. does not coincide with any of the genera currently known for the Afrotropical fauna and included in the mentioned key, from which it can be easily distinguished on the basis of the characters reported in the diagnosis above and shown in Fig. 21.
description: Published as part of Selis, Marco & Carpenter, James M., 2024, Revision of the Afrotropical genus Afrepipona Giordani Soika, 1965 and description of Afrepsilon gen. nov. (Hymenoptera: Vespidae: Eumeninae), pp. 1-80 in European Journal of Taxonomy 944 on pages 58-61, DOI: 10.5852/ejt.2024.944.2607, http://zenodo.org/record/12808564