Carinostigmus aterrimus (R. Turner)

Pulawski, Wojciech J. & Gracy, Ramasamy Gandhi, 2018, Redescription of Two Indian Stigmina (Hymenoptera: Crabronidae), Proceedings of the California Academy of Sciences 64 (10), pp. 333-340 : 335-339

Carinostigmus aterrimus (R. Turner)

Stigmus aterrimus R. Turner, 1917:174 , ♀. Holotype: ♀, India: Tamil Nadu: Nilgiri Hills: Coonoor ( BMNH), examined. – Tsuneki, 1954:3 (in key to Eurasian Stigmus ), 10 (original description copied). – As Carinostigmus aterrimus : R. Bohart and Menke, 1976:191 (new combination, in checklist of world Sphecidae ).

Tsuneki (1954) included this species in his revision of the Eurasian Stigmus , but had seen no specimens. Based on the original description, however, he correctly recognized that the species was a Carinostigmus (treated as a subgenus of Stigmus at that time). He also correctly recognized the diagnostic characters.

RECOGNITION.— Carinostigmus aterrimus differs from its congeners in having the mandible black at least basally (brownish apically to mostly brown) rather than yellow, and the trochanters black (at least mid- and hindtrochanters) rather than testaceous.

REDESCRIPTION.— Inner eye margins slightly converging below in female ( Fig. 8 ), more so in male ( Fig. 15 ). Frons microareolate, outside of scapal basin also minutely ridged. Paraorbital groove crenulate, moderately broad along anterior head surface. Horizontal portion of frons and postocellar area almost unsculptured, with only widely spaced microscopic punctures. Midfrontal carina well defined but markedly thinner just before midocellus, below midlength forming narrow, erect projection. Occipital carina narrow, not crenulate in female, crenulate ventrally in male ( Fig. 18 ). Underside of head lineate laterally but not mesally ( Fig. 18 ). Free margin of clypeal lobe shallowly emarginate, slightly more so in male ( Fig. 15 ) than in female ( Figs 9 , 10 ), free margin laterally of lobe gently incurved, not forming projection ( Figs. 9 , 10 , 15 ). Transverse carina of pronotal collar well defined, spicate laterally, not emarginate mesally in female, slightly emarginate in male (emargination smaller than in C. costatus Krombein ). Scutum with scattered punctures slightly larger and denser than those on head, not foveate along flange ( Fig. 12 ); notaulus impressed, crenulate, shorter than distance between notauli; parapsidal line inconspicuous in female, conspicuous in male; posterior part of scutum conspicuously foveolate adjacent to hindor nearly so, markedly larger than greatest width of hypersternaulus (smaller in C. costatus ); ridges along mesopleuron posterior margin (between hypersternaulus and midcoxa) fine, somewhat conspicuous in female from Kunchappanai, and well defined in male. Propodeal enclosure with median carina and oblique, somewhat irregular ridges emerging from it ( Fig. 14 ), without unridged area apically; propodeal dorsum outside of enclosure obliquely ridged; propodeal side longitudinally ridged; posterior surface coarsely rugose ventrally, in holotype dorsally unsculptured on each side of median sulcus (unsculptured area attaining apex of enclosure), but all rugose in other specimens examined. Gastral petiole in dorsal view 6.0 × as long as wide at middle in female, 8.2 × in male.

Body black, shiny except for pale yellow pronotal lobe, with the following testaceous: scape ventrally in some specimens, labrum, palpi, articulation between trochanters and femora, foretrochanter in one female from Yelahanka and in male, also articulation between forefemur and foretibia in male, anterior surface of foretibia, posterior surfaces of mid- and hindtibia, and tarsi; mandible black except brownish apically, but brown except black basally in female from Kunchappanai, and black basally and apically and light brownish mesally in male.

♀.— Head moderately narrowed behind eyes in dorsal view ( Fig. 11 ), its width next to occipital carina equal to 0.56 × its greatest width. Postocellar area elongate ( Fig. 11 ). Labrum (invisible in holotype) pentagonal, its lateral margins diverging ventrally near base, converging and straight over most of their length, apex rounded ( Fig. 10 ). Pygidial plate oval, microsculptured. Length 4.7-5.3 mm

♂.— Head markedly narrowed behind eyes in dorsal view ( Fig. 17 ), its width next to occipital carina equal to 0.33-0.35 × its greatest width. Postocellar area markedly shorter than in female ( Fig. 17 ). Labrum shallowly, broadly emarginate apically ( Fig. 18 ). Three apical flagellomeres with placoids. Genitalia: Fig. 19 . Length 5.6-5.9 mm.

RECORDS ( Fig. 7 ).— INDIA: Karnataka: Attur: Yelahanka at 13°10′N 77°56′E (1 ♀, CAS; 1 ♀, 2 ♂, NBAIR:) . Tamil Nadu: Nilgiri Hills: Coonoor at 11.3530°N 76.7959°E (1 ♀, BMNH, holotype of Stigmus aterrimus R. Turner ) and Kunchappanai 15 km SE of Kotagiri at 11°22′N 76°56′E (1 ♀, CAS) .

Figures

FIGURES 8–9. Carinostigmus aterrimus (R. Turner), holotype female,. (8) Head in frontal view; (9) Clypeus and adjacent frons.

FIGURES 15–19. Carinostigmus aterrimus (R. Turner), male. (15) Head in frontal view; (16) Clypeus and adjacent frons; (17) Head in dorsal view; (18). Underside of head; (19) Genitalia.

FIGURES 10–14. Carinostigmus aterrimus (R. Turner), holotype female, except Figs. 10 and 13. (8) Head in frontal view; (9) Clypeus and adjacent frons; (10) Clypeus and adja- cent frons, specimen from Kunchappanai; (11) Head in dor- sal view; (12) Scutum; (13) Mesopleuron, specimen from Yelahanka. (14) Propodeal dorsum.

FIGURE 7. Map of Indian subcontinent with collecting localities of Stigmus cuculus Dudgeon (square) and Carinostigmus aterrimus (R. Turner) (circles).