Stethantyx erwini Khalaim & Sääksjärvi, 2015

Khalaim, Andrey I., Sääksjärvi, Ilari E. & Bordera, Santiago, 2015, Tersilochinae of Western Amazonia (Hymenoptera: Ichneumonidae). Genus Stethantyx Townes, part 2, Zootaxa 3981 (1), pp. 95-106 : 96-98

Stethantyx erwini Khalaim & Sääksjärvi , sp. nov.

( Figs 1 , 7–11 )

Description. Female. Body length 4.6 mm. Fore wing length 2.9 mm.

Head strongly rounded behind eyes in dorsal view; temple almost half as long as eye width. Mandible with upper tooth very long, almost 3.0× longer than lower tooth. Clypeus ( Fig. 8 ) about 3.0× as broad as long, lenticular, slightly convex in lateral view, smooth, distinctly punctate in upper part. Malar space 0.6× as long as basal width of mandible. Antennal flagellum ( Fig. 7 ) short, distinctly narrowed towards apex, with 17 flagellomeres; all flagellomeres (except basal and subapical ones) about as long as broad. Face and frons dull, distinctly and densely punctate on finely granulate background (face smooth between punctures centrally); face with very weak prominence centrally. Vertex with fine and dense punctures, dull and finely granulate. Temple with moderately dense, fine but sharp punctures, smooth and shining between punctures. Occipital carina complete.

Notaulus with a very strong wrinkle ( Fig. 9 ). Mesoscutum densely punctate on granulate background. Scutellum with lateral longitudinal carinae extending from its base to hind end but not joining posteriorly. Foveate groove ( Fig. 9 ) situated in anterior 0.6 of mesopleuron, broad and deep, strongly oblique, with strong transverse wrinkles, reaching prepectal carina anteriorly. Mesopleuron with distinct punctures, smooth between punctures centrally and finely granulate peripherally, with impunctate area anteriorly (above foveate groove). Propodeum distinctly granulate, dorsolateral area with fine (mostly indistinct because of granulation) punctures. All propodeal carinae complete and strong, transverse carina with weak adjacent wrinkles ( Fig. 10 ). Propodeum with basal keel 0.3× as long as apical area ( Fig. 10 ). Propodeal spiracle separated from pleural carina by half diameter of spiracle ( Fig. 9 ). Apical area flat, widely rounded anteriorly ( Fig. 10 ).

Fore wing with first and second abscissae of radius meeting at right angle (second abscissa curved). Intercubitus somewhat shorter than abscissa of cubitus between intercubitus and second recurrent vein, both short and slightly thickened. Metacarpus not reaching apex of fore wing. Hind wing with nervellus vertical. Legs moderately slender. Hind femur 3.9× as long as broad and 0.85× as long as tibia.

First tergite 3.0× as long as posteriorly broad, smooth, petiole distinctly striate laterally before glymma. Glymma situated behind middle of tergite, rather deep, joining by distinct furrow to ventral part of postpetiole. Second tergite as long as anteriorly broad. Thyridial depression shallow, triangular, about as long as broad. Ovipositor upcurved, with shallow dorsal subapical depression and tooth before this depression, and two fine teeth on ventral side ( Fig. 11 ); sheath 1.4× as long as first tergite and 1.6× as long as hind tibia.

Head black, clypeus yellow-brown; palpi and mandible (teeth reddish black) yellow. Antenna with scape and pedicel yellow, flagellum black. Mesosoma reddish brown with mesoscutum, scutellum, postscutellum and propodeum black. Tegula yellowish. Pterostigma brown. Legs brownish yellow, hind femur centrally and tibia apically brown. First metasomal tergite brownish black; following tergites predominantly brownish yellow, tergites 2–4 dorsally brown to dark brown.

Male. Flagellum somewhat more slender than in female, flagellomeres slightly elongate. Malar space 0.4–0.5× as long as basal width of mandible. Propodeal spiracle separated from pleural carina by half diameter of spiracle. Second tergite elongate. Otherwise similar to female.

Etymology. Named in honour of T.L. Erwin, collector of the type material.

Material examined. Holotype female ( USNM) Ecuador, Orellana Prov., Onkone Gare, 0º39′25.7′′ S, 76º27′10.8′′ W, 216.3 m, canopy fogging, 2.VII.1995, coll. T.L. Erwin et al.

Paratype. Ecuador, Orellana : 1 ♂ ( ZISP) same data as holotype, but 4.X.1995.

Distribution. Ecuador ( Orellana ).

Comparison. Stethantyx erwini sp. nov. is readily distinguished from other species of this genus as it has a propodeum with distinct basal keel and apical area widely rounded anteriorly ( Fig. 10 ), and short antennal flagellum, with only 17 flagellomeres ( Fig. 7 ). This species is also characterized by a reddish brown mesosoma with black mesoscutum, scutellum, postscutellum and propodeum ( Fig. 1 ), and a short second tergite.

Figures

FIGURES 1, 2. Stethantyx spp., ♀, holotype, habitus: 1 — S. erwini sp. nov.; 2 — S. radiata sp. nov.

FIGURES 7 – 11. Stethantyx erwini sp. nov., ♀, holotype: 7 — antenna, lateral; 8 — head, ventro-frontal; 9 — mesosoma, posterolateral (arrow indicates notaular wrinkle); 10 — propodeum, dorsal; 11 — apex of ovipositor, lateral.