Ctenocerus Dahlbom 1845
Creators: name: Shimizu, Akira
name: Broad, Gavin
name: Yoshimura, Jin
name: Pitts, James P.
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hymenoptera
Pompilidae
Ctenocerus

description: Genus Ctenocerus Dahlbom, 1845
Ctenocerus Dahlbom, 1845: 456
(type species: Ct. klugi Dahlbom, 1845, ♂, Caffraria, South Africa (Dahlbom 1845, 1856), by monotypy).
Clavelia Lucas, 1851: 418, 421 (sensu Arnold 1932). [In part*]
Euclavelia Arnold, 1932: 112, figs 35–36. (type species: Micropteryx fasciatus Smith, 1851, original designation and monotypic.) Syn. nov.
Remarks
*In his monograph on the African Claveliinae (= Ctenocerinae), Arnold (1932, 1935) described the following species and subspecies of Clavelia, i.e., Cl. (Protoclavelia) robusta Arnold, 1932, ♀; Cl. (Pr.) katangae Arnold, 1932, ♀; Cl. (Pr.) flavicauda Arnold, 1932, ♀; Cl. (Clavelia) ramosa ramosa (Smith, 1865), ♀ ♂; Cl. (Cl.) r. minor Arnold, 1932, ♀ ♂; Cl. (Cl.) lacteipennis Arnold, 1932, ♂; Cl. (Cl.) pennata Bischoff, 1913, ♂; Cl. (Cl.) capensis Bischoff, 1913, ♂; Cl. (Cl.) decipiens decipiens Arnold, 1932, ♂; Cl. (Cl.) decipiens pallidicornis Arnold, 1932, ♂; Cl. (Cl.) algoensis Arnold, 1932, ♂; Cl. (Cl.) pannosicornis Aronod, 1932, ♂; Cl. (Cl.) amplicornis Arnold, 1932, ♂; Cl. (Cl.) fuscipennis Arnold, 1932, ♂; Cl. (Cl.) croceicornis Arnold, 1932, ♂; Cl. (Cl.) auranticornis Arnold, 1932, ♂; and Cl. (Cl.) modesta Arnold, 1935, ♀. Afterward, Arnold (1934) recognized Clavelia to be a junior synonym of Ctenocerus, as stated in the introduction. From our examination of females of four species (Cl. robusta, Cl. katangae, Cl. flavicauda, Cl. ramosa; see Supp. file 1) and Arnold’s descriptions, it is apparent that all females of Clavelia sensu Arnold (1932, 1935) belong to Cternocerus. Hence, Cl. robusta, Cl. katangae, Cl. flavicauda, Cl. ramosa, and Cl. modesta should be transferred to Ctenocerus. The problems lie in the above species based only on the males. As far as being based on Arnold’s (1932: fig. 10) description, Clavelia algoensis certainly belongs to Ctenocerus because the male has the frontal bridge (median longitudinal strip on lower frons connecting frons and clypeus on same plane). We examined two males of Clavelia decipiens (Supp. file 1) and found that the species should be transferred to Paraclavelia. We were not able to determine genera of the other species, because we were not able to examine male specimens of these species and Arnold’s (1932) descriptions are insufficient for our generic identification.
Diagnosis
Ctenocerus is distinguished from other genera of Pompilidae by the combination of the following features.
Both sexes
Clypeus distinctly narrower than LID (Figs 1A, F, J, 2E, G, I, 3D, 4A, D, G, 5D), rectangular or trapezoidal.
Female
Lower frons lateral to and ventral to antennal sockets deeply depressed, leaving median frontal bridge (Figs 1A, F, J, 2E, G, I, 3D, arrow). Clypeus lamelliform (flattened plate), usually truncate apically, its surface flat or slightly convex and polished, deeply and broadly depressed basilaterally. Scape compressed laterally, curved outward with lateral face concave (Figs 2B, 3E). Pronotum as long as or longer than mesoscutum at middle (Figs 1G, K–L, 3A); collar situated slightly below level of dorsum (Figs 1C, H, 2A, F, H, J, 3H); lateral face vertical, traversed by L-shaped groove (posterior part of streptaulus) (Figs 2H, 3H). Fore tibia with stout, decurved spine apicomesally (Figs 2C, 3F, arrow). All tarsal claw bifid. S2 with transverse groove (Fig. 3I).
Male
Vertex strongly convex and chevron-shaped above level of eye tops (Figs 4A, D, G, 5D). Lower frons with median frontal bridge, this being often narrow and slightly depressed below level of supra-antennal area (Figs 4A, D, G, 5D, arrow). Flagellomeres 1–10 uniramous (each flagellomere with lobe-like projection only basilaterally; Fig. 4B–C, J), biramous (each flagellomere with lobe-like projection both basilaterally and basimesally; Fig. 4D–E, H), or catenulate (cylindrical and connected with each other only by a hidden dorsal peduncle; Fig. 5H). Propodeum densely punctate, sometimes finely and transversely rugulose or minutely reticulate-rugulose, and covered with long pubescence (Figs 4K, 5B). Fore and mid tarsal claws bifid; hind tarsal claw bifid, or edentate, rectangularly bent subapically and their pair not very divergent.
Redescription (as a complement to Arnold’s (1932) description, based on the type species)
Female
MEASUREMENTS. Small to fairly large wasps, 9 to 22 mm in length.
HEAD. Usually slightly wider than high (Figs 1A, J, 2E, G, I, 3D) (narrower than high in C. klugi (Fig. 1F)). Vertex moderately to strongly convex above level of eye tops (Figs 1A, F, J, 2E, G, I, 3D) with surface fairly flattened; juncture of its anterior and posterior faces sharply or subacutely carinate medially (Figs 1D, G, K, 3E). Frons broad, half of this much broader than eye, usually polished; upper frons fairly flat. Frontal bridge various in width, e.g., very narrow and linear in the subgenus Protoclavelia Arnold, 1932 (Figs 1A, 2E) and broader than scape width in C. klugi (Fig. 1F), C. fasciatus (Fig. 1J) and C. srilankae sp. nov. (Fig. 3D). Malar space much shorter than half of fore tarsomere 1 thickness (Figs 2F, H, 3D). Mandible usually long and curved apically with small tooth subapically on inner margin (Figs 2G, I, 3D) (in C. klugi (Fig. 2M), very stout and strongly curved, laminated and polished anteriorly with broad outer rim on apical half, that being delimited from main part by deep groove). Maxillary palpus short, palpomeres 4–6 not much shorter or longer than palpomere 3. Gena, in dorsal view, variously developed but not swollen (Figs 1B, L, 3E). Ocelli forming an obtuse-angled triangle (Figs 1B, L, 3E, 4B, H, 5C). Occipital suture present only dorsally, its uppermost portion situated immediately below vertex crest (Fig. 1G, K).
MESOSOMA. Pronotum with dorsum flattened medially, gradually sloping anteriorly, its lateral margin somewhat convex (Figs 1B, L, 3E); streptaulus absent medially; declivity short and gently sloping or practically absent because of continuous transition from dorsum to collar (Figs 1C, 2H); juncture of lateral face and dorsum usually bluntly carinate (Figs 1K, 2H, 3H) (broadly rounded in C. klugi (Fig. 1G)). Mesoscutum small (Figs 1K–L, 3A), flattened above; parapsides narrowly raised posterolaterally (Fig. 3B); parapsidal sulcus deeply impressed, divergent anteriorly. Scutellum flattened above, scarcely raised above level of mesoscutum (Fig. 1H). Metapostnotum variously developed (Figs 1E, H, M, 3B), sometimes short or linear medially. Propodeal dorsum gently convex or rather flattened longitudinally (Figs 1H, 2A, H, 3G–H) with stigma from anterior margin of propodeum by about twice its own length (Figs 1E, G, M, 3B); declivity rather flattened but not distinctly delimited from dorsum (Figs 1H, 2A, F, H, J, 3H), transversely rugose (Fig. 3B).
WINGS. FW with three SMCs (Figs 1I, 3C). Pterostigma fairly long, its base much longer than cross-vein 2 r-rs. Marginal cell lanceolate, acute at apex. Second abscissa of vein M (basal vein) curved. Last abscissa of vein M not attaining outer wing margin. Cross-vein cu-a originating distal to separation of vein M+CuA. HW cross-vein cu-a originating basal to (Figs 1I, 2J), at, or distal to fork of vein M+CuA (Figs 1C, 3C).
LEGS. Fore tarsomeres 2–4 combined much shorter than fore tarsomere 1. Fore femur somewhat swollen, as thick as or thicker than mid femur (Figs 2A, F, 3H). Mid and hind femora with distinct basal ring. Mid tibia with short spines dorsally. Hind tibia with spines short or rudimentary dorsally (Figs 2K, 3J) and apically (Fig. 2L). Orbicula small, narrower than 0.6× width of tarsomere 5, with orbicular pecten consisting of short, fine, straight setulae. Tarsomere 5 with short, irregularly arranged spines or almost lacking spines beneath.
METASOMA. T1 usually petiolate (narrower immediately behind articulation than its width at articulation itself; Fig. 3A) or parallel-sided anteriorly (Fig. 1E, M). S6 not or slightly compressed laterally with (Figs 2D, 3I) or without median carina.
Male
MEASUREMENTS. Much smaller and slenderer than female, 5.5 to 18 mm in length.
HEAD. Broader than long (Figs 4A, D, G, 5D). Juncture of anterior and posterior faces of vertex rounded (Figs 4B, E, H, 5C). Frons usually with numerous long erect setae; upper frons transversely convex; supra-antennal area not or only slightly produced anteriorly, not overhanging antennal radicle (Figs 4C, F, I, 5G). Clypeus with surface slightly convex. Malar space as long as or longer than half of fore tarsomere 1 thickness (Figs 4A, C–D, G, I, 5D). Scape short (Figs 4B–D, I–J, 5C, G), barrel-shaped unlike in female, sometimes with numerous setae, usually those on ventral side longer than elsewhere (Fig. 4I). In uni- or biramous flagellum, projection(s) on each flagellomere prolonged anteriorly, its outer face convex, inner face concave, both faces with short, dense spinules. Mandible short with small tooth subapically on inner margin (Fig. 4A, G). Occipital suture complete, its uppermost portion situated somewhat deep below vertex crest (Fig. 5B).
MESOSOMA. Pronotum much shorter than mesoscutum medially (Figs 4H, 5A); collar situated deep below level of dorsum unlike in female (Figs 4C, F, I, 5G); streptaulus present (Fig. 5C); declivity vertical, flattened and polished (Figs 4C, F, I, 5G), its juncture with dorsum rounded; dorsum transversely convex and longitudinally declivous, usually gradually narrowing anteriorly (Figs 4E, H, 5C), truncate anteromedially with numerous long pubescence and setae, its juncture with lateral face rounded; L-shaped groove on lateral face obscure or absent (Figs 4C, F, 5G). Mesoscutum with parapsides narrowly reflexed posterolaterally (Fig. 5B). Disc of scutellum triangular (Figs 4K, 5B), scarcely or slightly raised above level of mesoscutum. Metanotum declivous. Metapostnotum longer than in female (Figs 4K, 5B). Propodeum with dorsum much longer than declivity (Figs 4C, 5F–G), parallel-sided (Fig. 5A–B) or gradually narrowing posteriorly; declivity not delimited from dorsum.
WINGS. HW cross-vein cu-a originating usually at or distal to separation of vein M+CuA (Fig. 5E), confluent with vein A, forming long smooth arc, but occasionally short, almost straight and oblique, meeting vein A forming obtuse angle (Fig. 4C).
LEGS. Apical margin of fore tibia with short, stout, decurved spine or lacking such spine mesally. Fore femur slender, thinner than mid femur (Figs 4C, I, 5G). Fore tarsomeres 2–4 combined as long as or shorter than fore tarsomere 1. Orbiculae of all legs similar to those of female or orbicula of hind leg remarkably small, its pecten absent. Fore and mid tarsal claws bifid; hind tarsal claw bifid, or edentate, rectangularly bent subapically and both claws parallel to each other or slightly divergent.
METASOMA. T1 not petiolate, gradually narrowing anteriorly. S2 without transverse groove. S6 with very small lateral hook posteriorly. Subgenital plate comparatively large, not compressed laterally (Fig. 5L).
Distribution
Africa (Palaearctic and Afrotropical Regions) and South Asia (Sri Lanka).
description: Published as part of Shimizu, Akira, Broad, Gavin, Yoshimura, Jin & Pitts, James P., 2022, First records of the spider wasps Ctenocerus Dahlbom and Paraclavelia Haupt from Asia, with discussions on the systematics of Ctenocerinae (Hymenoptera: Pompilidae), pp. 101-131 in European Journal of Taxonomy 845 (1) on pages 104-108, DOI: 10.5852/ejt.2022.845.1957, http://zenodo.org/record/7258882