Ctenocerus Dahlbom, 1845

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), European Journal of Taxonomy 845 (1), pp. 101-131 : 121

Key to the genera Ctenocerus Dahlbom, 1845 and Paraclavelia Haupt, 1930

(The key is not specific to the Asian species but applies to the African species.)

Females

1. Lower frons lateral to and ventral to antennal sockets deeply depressed, leaving frontal bridge ( Figs 1A, F, J , 2E, G, I , 3D , arrow) this being continuous to clypeus on same plane; clypeus deeply and broadly depressed only basilaterally; fore femur swollen, thicker than mid femur ( Figs 2A, F, H, J , 3H ) ....................................................................................................... Ctenocerus Dahlbom, 1845

– Frontal bridge absent, i.e., lower frons deeply depressed lateral to antennal sockets and ventral to them across its whole width ( Figs 6A, D, G, J , 7D ); clypeus with deep depression across whole width of its base, depression being broader laterally than medially; fore femur not swollen ( Figs 6F, I , 7H ) .......................................................................................................... Paraclavelia Haupt, 1930

Males

1. Supra-antennal area of frons not or slightly produced anteriorly ( Figs 4C, F, I , 5G ); lower frons with frontal bridge ( Figs 4A, D, G , 5D , arrow), this being sometimes narrow and slightly depressed below level of supra-antennal area unlike in female .............................. Ctenocerus Dahlbom, 1845

– Supra-antennal area of frons produced into frontal ledge overhanging antennal radicle ( Fig. 8C, F, I ); frontal bridge absent ( Fig. 8A, D, G ), i.e., lowermost frons across its whole width depressed much below level of supra-antennal area and slightly below level of clypeus ... Paraclavelia Haupt, 1930

Based on these key characters, at least Ct. decipiens , which is known only from a male from South Africa, should be transferred to Paraclavelia . Examination of the males of this species has revealed that they bear the characteristics of Paraclavelia , i.e., the frons protruded over the antennal sockets ( Fig. 8F ) and lacking the frontal bridge ( Fig. 8D ), although the flagellum is biramous ( Figs 8D–F, K ). Moreover, the male of Ct. srilankae sp. nov. has the crenulate flagellum ( Fig. 5H ). Thus, the males of both Ctenocerus and Paraclavelia may have the flagellum uni- or biramous, or crenulate, as discussed below, invalidating this character as diagnostic for the genera as proposed by Arnold (1932).

Figures

Fig. 1. Females of Ctenocerus Dahlbom, 1845. A–E. C. robustus (Arnold, 1932) (#14) (NHMUK). F–I. C. klugi Dahlbom, 1845 (#8) (NHMUK). J–M. C. fasciatus (Smith, 1851) (#3) (NHMUK). A, F, J. Head, anterior view, arrow indicates frontal bridge. B, L. Head and anterior part of mesosoma, dorsal view. C, H. Head and mesosoma, lateral view. D, G, K. Head and mesosoma, dorsolateral view. E, M. Posterior part of mesosoma and anterior part of metasoma, dorsal view. I. Wings. Numbers in parentheses after species names are specimen numbers in Supp. file 1. Scale bars = 1 mm.

Fig. 2. Females of Ctenocerus Dahlbom, 1845. A–D. C. fasciatus (Smith, 1851) (#3) (NHMUK). E–F. C. flavicauda (Arnold, 1932) (#5) (NHMUK). G–H. C. ramosus Smith, 1865 (#16) (UMUT). I–J. C. lacteipennis (Arnold, 1932) (#12) (NHMUK).K–L. C. robustus (Arnold, 1932) (#14) (NHMUK). M. C. klugi Dahlbom, 1845 (#8) (NHMUK). A, F, H, J. Head and mesosoma, lateral view. B. Left scape, dorsolateral view. C. Right fore tibia, mesial view, arrow points to apicomesial spine on fore tibia. D. Apical part of metasoma, ventral view. E, G, I. Head, anterior view, arrow indicates frontal bridge. K. Left hind tibia, dorsal view. L. Apical part of left hind tibia, dorsal view. M. Mandible, anteroventral view. Numbers in parentheses after species names are specimen numbers in Supp. file 1. Scale bars: A–K, M = 1 mm; L = 0.5 mm.

Fig. 3. Ctenocerus srilankae Shimizu sp. nov., holotype, ♀ (NMNH). A. Whole body, dorsal view. B. Posterior part of mesosoma, dorsal view. C. Right wings. D. Head, anterior view, arrow indicates frontal bridge. E. Head and pronotum, dorsal view. F. Apical part of left fore tibia, mesial view, arrow indicates apicomesial spine on fore tibia. G. Whole body, lateral view. H. Head and mesosoma, lateral view. I. Metasomal sterna 2–6, ventral view. J. Left hind tibia, dorsal view. Scale bars: A–E, I–J = 1 mm; F = 0.5 mm; G–H = 2 mm.

Fig. 6. Females of Paraclavelia Haupt, 1930. A–C, O–P. P. caffer (Kohl, 1886) (#22) (NHMUK). D–F. P. crudelis (Smith, 1879) (#24) (NHMUK). G–I. P. rhodesiensis Arnold, 1832 (#33) (NHMUK). J–M. P. marshalli (Bingham, 1902) (#30) (NHMUK). N. P. somalica Arnold, 1932, holotype (#36) (NHMUK). A, D, G, J. Head, anterior view. B, E, H, K. Head and anterior part of mesosoma, dorsal view. C, F, I, L, N. Head and anterior part of mesosoma, lateral view. M. Apical part of left fore tibia, mesial view, arrow indicates apicomesial spine on fore tibia. O. Right scape, mesial view, arrow indicates longitudinal carina on mesial face of scape. P. Same, dorsolateral view. Numbers in parentheses after species names are specimen numbers inSupp. file 1. Scale bars: A–L = 1 mm; M = 0.2 mm; O–P = 0.5 mm. (N lacks a scale bar because of unavailable measurement data due to lack of access to the holotype.)

Fig. 7. Paraclavelia arabiae Shimizu sp. nov., holotype, ♀ (NHMUK). A. Whole body, dorsal view. B. Head and mesosoma, dorsal view. C. Right wings. D. Head, anterior view. E. Head and pronotum, dorsal view. F. Apical part of right fore tibia, mesial view, arrow indicates apicomesial spine on fore tibia. G. Whole body, lateral view. H. Head and mesosoma, lateral view. I. Metasoma, ventrolateral view. J. Right hind tibia, dorsal view. Scale bars: A–E, G–J = 1 mm; F = 0.5 mm.

Fig. 4. Males ofCtenocerus Dahlbom, 1845.A–C, J, L. C. lacteipennis (Arnold, 1932) (#13) (NHMUK). D–F, K. C. klugi Dahlbom, 1845 (#11) (NHMUK). G–I. C. ramosus Smith, 1865 (#18) (UMUT). A, D, G. Head, anterior view, arrow indicates frontal bridge. B, E, H. Head and anterior part of mesosoma, dorsal view. C, F, I. Head and mesosoma, lateral view. J. Left flagellum, mesial view. K. Posterior part of mesosoma, dorsal view. L. Subgenital plate, ventral view. Numbers in parentheses after species names are specimen numbers in Supp. file 1. Scale bars: A–K = 1 mm; L = 0.5 mm.

Fig. 5. Ctenocerus srilankae Shimizu sp. nov., paratype, ♂ (NHMUK). A. Whole body, dorsal view. B. Head and mesosoma, dorsoposterior view. C. Head and anterior part of mesosoma, dorsal view. D. Head, anterior view, arrow indicates frontal bridge. E. Left wings. F. Whole body, lateral view. G. Head and mesosoma, lateral view. H. Apical part of right flagellum, lateral view. I. Subgenital plate, ventral view. J. Genitalia, dorsal view. K. Same, ventral view. L. Right side of genitalia. Scale bars: A–G = 1 mm; H–L = 0.5 mm.

Fig. 8. Males of Paraclavelia Haupt, 1930. A–C, J. P. katbergensis Arnold, 1948 (#29) (NHMUK). D–F, K. P. decipience (Arnold, 1932) (#28) (UMUT). G–I. P. crudelis (Smith, 1879) (#26) (NHMUK). A, D, G. Head, anterior view. B, E, H. Head and anterior part of mesosoma, dorsal view. C, F, I. Head and mesosoma, lateral view. J. Right antenna, anterior view. K. Right flagellum, dorsal view. Numbers in parentheses after species names are specimen numbers in Supp. file 1. Scale bars = 1 mm.