Stethantyx undulata 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 : 102-104

Stethantyx undulata Khalaim & Sääksjärvi , sp. nov.

( Figs 4, 6 , 19–23 )

Description. Female. Body length 4.7 mm. Fore wing length 2.8 mm.

Head strongly rounded behind eyes in dorsal view ( Fig. 20 ); temple short, 0.35× as long as eye width. Mandible with upper tooth distinctly longer than lower tooth. Clypeus broad, lenticular, slightly convex in lateral view, smooth, finely punctate in upper part. Malar space 0.8–0.9× as long as basal width of mandible. Antennal flagellum ( Fig. 19 ) narrowed towards apex, with 19–20 flagellomeres (20 flagellomeres in holotype); subbasal flagellomeres 1.8–2.0×, subapical flagellomeres 1.4–1.5× as long as broad. Face and frons finely and densely punctate (punctures sometimes indistinct) on smooth, dull or weakly shining background; face with very weak prominence centrally. Vertex strongly impressed posteriorly, with fine indistinct punctures, weakly shining. Temple smooth and shining, with fine and sparse punctures. Occipital carina complete.

Notaulus absent represented by a small tubercle distant from anterolateral margin of mesoscutum ( Figs 19, 20 ). Mesoscutum and scutellum very finely granulate, dull, indistinctly punctate. Scutellum with lateral longitudinal carinae short, developed in its anterior 0.3. Foveate groove ( Fig. 21 ) situated in anterior 0.7 of mesopleuron, short and broad, oblique, deep, with transverse wrinkles, not reaching prepectal carina anteriorly. Mesopleuron smooth and weakly shining, with very fine indistinct punctures. Dorsolateral area of propodeum smooth and weakly shining. Transverse carina of propodeum without adjacent wrinkles. Basal area indistinct, impressed, with weak longitudinal wrinkles ( Fig. 22 ); basal part of propodeum 0.3× as long as apical area. Propodeal spiracle separated from pleural carina by one diameter of spiracle. Apical area flat, rounded anteriorly ( Fig. 22 ).

Fore wing ( Fig. 6 ) with first and second abscissae of radius meeting at right angle (second abscissa straight). Intercubitus longer than abscissa of cubitus between intercubitus and second recurrent vein, both slightly thickened. Metacarpus almost reaching apex of fore wing. Hind wing with nervellus reclivous. Legs slender. Hind femur 4.8× as long as broad and 0.85× as long as tibia.

First tergite slender, 3.8× as long as posteriorly broad, smooth, petiole distinctly striate laterally before glymma. Glymma situated near middle of first tergite, deep, joining by very weak furrow to ventral part of postpetiole ( Fig. 21 ). Second tergite about twice as long as anteriorly broad. Thyridial depression long, more than 3.0× as long as broad. Ovipositor very long, slender, upcurved, distinctly sinuate at apex, with extreme apex strongly upcurved ( Fig. 23 ); sheath about 4.5× as long as first tergite and almost 4.0× as long as hind tibia.

Head yellowish orange with frons, vertex and upper half of temple reddish brown; palpi and mandible (teeth reddish) yellow. Antenna with scape and pedicel yellow, flagellum fuscous (pale basally, gradually darkening towards apex). Mesosoma (including tegula) yellowish orange. Pterostigma brown. Legs yellow, hind femur and tibia brown. First metasomal tergite brown; following tergites predominantly yellow, tergites 2–5 dorsally pale brown.

Male. Similar to female. Flagellum with 18 flagellomeres.

Variation. This is a very uniform species without obvious variation.

Etymology. Named from the Latin undulatus (wavy) on account of its sinuate ovipositor apex.

Material examined. Holotype female ( USNM), Ecuador, Orellana Prov., Onkone Gare, 0º39′25.7′′ S, 76º27′10.8′′ W, 216.3 m, canopy fogging, 4.X.1994, coll. T.L. Erwin et al.

Paratypes. Ecuador, Orellana : 1 ♂ ( ZMUT) same data as holotype, but 7.VII.2006. Peru, Loreto: 1 ♀ ( ZISP) Iquitos Area, Mishana, varillal, 16.X–1.XI.1998, coll. I.E. Sääksjärvi et al. 1 ♀ ( UNSM) same data, but 16.XI–1.XII.1998. 1 ♀ ( UNSM) same data, but clayish soil, 16.XI–1.XII.1998. 1 ♀ ( ZMUT) Iquitos Area, Allpahuayo, clayish soil, 1–15.XII.2000, coll. I.E. Sääksjärvi et al. 1 ♀ ( BMNH) same data, but varillal, 17.XI– 3.XII.1998. 1 ♀ ( ZMUT) same data, but white sand, 4–15.X.2000.

Distribution. Ecuador ( Orellana ), Peru (Loreto).

Comparison. The new species differs from three other species with first and second abscissae of radius rightangled by the combination of the predominantly yellowish orange body ( Fig. 4 ), short and longitudinally wrinkled basal part of propodeum, and a very long and apically sinuate ovipositor ( Fig. 23 ).

Figures

FIGURES 3 – 6. Stethantyx rufispa sp. nov., ♀, holotype: 3 — habitus, lateral; 5 — wings. Stethantyx undulata sp. nov., ♀, holotype (4) and paratype (6): 4 — habitus, lateral; 6 — wings.

FIGURES 19 – 23. Stethantyx undulata sp. nov., ♀, holotype: 19 — head with antennae, lateral; 20 — anterior part of mesosoma, lateral; 21 — head, mesosoma and base of metasoma, lateral; 22 — propodeum, dorsal; 23 — apex of ovipositor, lateral.