Stethantyx amazonica Khalaim & Sääksjärvi, 2013

Khalaim, Andrey I., Sääksjärvi, Ilari E. & Bordera, Santiago, 2013, Tersilochinae of Western Amazonia (Hymenoptera: Ichneumonidae). Genus Stethantyx Townes, part 1, Zootaxa 3741 (3), pp. 301-326 : 305-307

Stethantyx amazonica Khalaim & Sääksjärvi , sp. nov.

( Figs 5–8 , 52 )

Comparison. Very similar to the Costa Rican S. cecilia Khalaim & Broad in having a pale median band on the antenna and black head and mesosoma ( Fig. 52 ), but differs from this species in the flagellum with 23–25 segments (30–32 segments in S. cecilia ), a somewhat shorter and wider basal area of the propodeum, and the colour pattern of the hind leg (in S. amazonica sp. nov. the hind tibia and femur are dark brown to black, strongly contrasting with a white coxa and trochanters, whereas in S. cecilia , coxa, trochanters, femur and tibia are more or less uniformly yellowish brown, with the tibia and femur sometimes slightly infuscate).

Description. Female. Body length 7.2 mm. Fore wing length 4.4 mm.

Head very strongly rounded behind eyes in dorsal view; temple 0.43× as long as eye width. Mandible with upper tooth much longer than lower tooth. Clypeus lenticular, weakly convex in lateral view, smooth, with distinct punctures in upper part. Malar space 0.4–0.5× as long as basal width of mandible. Antennal flagellum weakly narrowed towards apex, with 22–25 flagellomeres (25 flagellomeres in holotype); subbasal flagellomeres 1.3–1.7× and subapical flagellomeres 1.2–1.3× as long as broad. Face very densely punctate, with elongate prominence centrally. Frons very densely punctate, dull. Vertex and temple with fine but sharp, moderately dense punctures, smooth between punctures; vertex dull, temple shining. Hypostomal carina absent.

Notaulus absent or as weak wrinkle. Mesoscutum finely granulate and very densely punctate. Scutellum finely granulate, punctate, with lateral longitudinal carinae reaching from its base to about midlength. Foveate groove situated in anterior 0.7 of mesopleuron, strongly oblique, deep, with strong transverse wrinkles, not reaching prepectal carina anteriorly. Mesopleuron with fine but distinct punctures, smooth between punctures, with impunctate area centrally (above foveate groove). Propodeum granulate, dull, dorsolateral area with fine (often indistinct) and dense punctures. Transverse carina with very short wrinkles adjacent to carina. Basal area of propodeum weakly widened anteriorly or more or less rectangular, 1.5–2.0× (1.5× in holotype) as long as broad and about 0.37× as long as apical area. Propodeal spiracle separated from pleural carina by 0.5–1.0× diameter of spiracle. Apical area flat, rounded or truncate anteriorly.

Fore wing with first and second sections of radius angled about 110°. Intercubitus distinctly longer than abscissa of cubitus between intercubitus and second recurrent vein. Metacarpus almost reaching apex of fore wing. Hind wing with nervellus distinctly inclivous.

Legs slender. Hind femur 4.6× as long as broad and 0.86× as long as tibia. Hind spurs almost straight.

First tergite slender, 3.9× as long as posteriorly broad, smooth, petiole finely striate or coriaceous laterally before glymma. Glymma situated somewhat behind middle of tergite, moderately large, joining by shallow groove to ventral part of postpetiole. Second tergite twice as long as anteriorly broad. Thyridial depression long, more than 3.0× as long as broad. Ovipositor upcurved, with shallow dorsal subapical depression; sheath about 1.5× as long as first tergite and hind tibia.

Head black; clypeus (upper margin brown to brownish black), palpi and mandible (teeth reddish black) brownish yellow. Antenna with scape and pedicel brownish yellow, flagellum fuscous with median 3 to 9 flagellomeres (7 flagellomeres in holotype) white (rarely pale band vanishing and flagellum entirely fuscous). Mesosoma black with propleuron and anterior part of pronotum widely whitish; sometimes mesosoma with profuse reddish brown marks. Tegula brown to brownish black. Pterostigma brown. Fore and mid femora, tibiae and tarsi brownish yellow. All coxae and trochanters white. Hind femur and tibia brown to black, tarsus more or less infuscate. First metasomal tergite brownish black, following tergites yellow ventrally to brownish yellow dorsally, dorsal surface of tergite 2 (except narrow yellow band posteriorly) brown to black, anterior half of tergite 3 dorsally brown.

Male. Unknown.

Variation. Colour pattern of mesosoma varies from dark reddish brown to black with propleuron and broad band on anterior margin of pronotum whitish; often mesosoma is black with profuse reddish brown markings. Some specimens from Peru have flagellum with very weak pale band or without pale band. Specimens with unicolourous flagellum usually have flagellum with 28–30 segments, and these specimens are excluded from the type material and from the description above. This may be a rather polymorphic species, or a complex of similar species.

A single specimen from Ecuador has entirely black flagellum with 32 segments and strongly compressed, transverse basal flagellomeres, extremely long upper tooth of mandible, ventrally more strongly convergent eyes and shorter malar space, which is almost 0.2× as long as basal width of mandible. This may be a new species or aberrant specimen of S. amazonica sp. nov., but additional material is required to solve this problem. This specimen is also not included in the type material.

Etymology. The name refers to its distribution in the Amazonian lowland rain forest area.

Material examined. Holotype female (UNSM), Peru, Madre de Dios reg., Los Amigos, 241.7 m, 5– 12.VI.2008, coll. I. Gómez.

Paratypes. Peru, Loreto: Iquitos Area, Allpahuayo, clayish soil, coll. I.E. Sääksjärvi et al.: 1 ♀ (CEUA) 18.IX–4. X.1998, 1 ♀ (UNSM) 5–17. XI.1998, 1 ♀ (UNSM) 3–17. XII.1998, 1 ♀ (ZISP) 3–22. V.2000, 1 ♀ (UNSM) 11–29.VI.2000. 2 ♀ (ZMUT) same data, but white sand, 16.IV–3.V, 22.V–11.VI.2000. Iquitos Area, Mishana, clayish soil, coll. I.E. Sääksjärvi et al.: 1 ♀ (UNSM) 1–16. IX.1998, 1 ♀ (BMNH) 1–16.X.1998. Same data, but varillal: 1 ♀ (ZISP) 1–16. XI.1998, 2 ♀ (ZMUT) 16.XII.1998 – 1.I.1999. Madre de Dios: 1 ♀ (ZMUT) same data as holotype, but 233.4 m, 26.VI–3.VII.2008.

Non-type material. Peru, Loreto: 1 ♀ (ZMUT) Iquitos Area, Allpahuayo, clayish soil, 22.V–17.VI.2000, coll. I.E. Sääksjärvi et al. 2 ♀ (ZMUT, ZISP) same data, but varillal, 4–20.X.1998. 1 ♀ (ZMUT) same locality, 30º58′00′′ S, 73º25′16′′ W, 17–23.X.2011, coll. I. Gómez & I.E. Sääksjärvi. 1 ♀ (ZMUT) Iquitos Area, Mishana, clayish soil, 16.XI–1.XII.1998, coll. I.E. Sääksjärvi et al. Ecuador, Orellana : 1 ♀ (ZMUT) Onkone Gare, 0º39′25.7′′ S, 76º27′10.8′′ W, 216.3 m, canopy fogging, 10.X.1994, coll. T.L. Erwin et al.

Distribution. Peru (Loreto, Madre de Dios),? Ecuador ( Orellana ).

Figures

FIGURES 1 – 8. Stethantyx alajuela, ♀: 1 — head with antennae, anterolateral; 2 — head, frontal; 3 — scutellum, metanotum and propodeum, dorsal; 4 — metasomal segments 2 and 3, dorsal. Stethantyx amazonica sp. nov., ♀, holotype: 5 — head with antennae, anterolateral; 6 — hind leg (without apex of tarsus), lateral; 7 — propodeum, dorsal; 8 — metasomal segments 2 and 3, dorsal.

FIGURES 52 – 55. Stethantyx spp., ♀, holotypes, habitus: 52 — S. amazonica sp. nov.; 53 — S. aurantia sp. nov.; 54 — S. juninensis sp. nov.; 55 — S. loretosa sp. nov. Scales 1.0 mm.