Trieces isolatus, Ranjith & Priyadarsanan, 2022

Ranjith, A. P. & Priyadarsanan, Dharma Rajan, 2022, First description of the metopiine genus Trieces Townes, 1946 (Hymenoptera: Ichneumonidae) from the Indomalayan region with three new species from India, European Journal of Taxonomy 794 (1), pp. 1-17 : 8-11

Trieces isolatus sp. nov.

urn:lsid:zoobank.org:act:4A160D4D-B82F-451B-91A7-7FA175BF0A8C

Figs 3–4

Differential diagnosis

The new species comes closer to T. orientalis sp. nov. but differs based on the characters listed in the taxonomic key. Additionally, T. isolatus sp. nov. differs from the latter in having the following characters: hind coxa yellowish brown (vs black in T. orientalis sp. nov.), pterostigma yellow (vs black in T. orientalis sp. nov.), first metasomal tergite longer than wide (vs wider than long in T. orientalis sp. nov.), antenna with 20 flagellomeres (vs 23 in T. orientalis sp. nov.).

Etymology

The species name refers to the isolated pit below the metapleural slit.

Material examined

Holotype INDIA • ♀; Karnataka, Chamarajanagar, Biligiri Ranga Hill Wild Life Sanctuary, Parasakatte ; 12°01.414′ N, 77°06.551′ E; 795 m a.s.l.; 30 Sep.–14 Oct. 2005; Malaise trap; D.R. Priyadarsanan leg.; AIMB.

Description

Female

MEASUREMENTS. Body length 3.6 mm, length of fore wing 2.4 mm.

HEAD. Head transverse in dorsal view, not narrowed posteriorly behind eyes, 1.7 × as wide as long medially; frons smooth, setose; occiput smooth, glabrous medially rest setose; temples smooth dorsally, setose, not convex, their length 0.7× as long as transverse eye diameter in lateral view. Occipital carina present. Eyes sparsely setose. Distance from lateral ocellus to eye equal to diameter of ocellus. Distance between lateral ocelli 2.0× distance from lateral ocellus to eye. Face not convex in lateral view, 0.9× as wide as long in anterior view, slightly narrowed posteriorly, punctate, setose. Clypeus separated from face by shallow indistinct depression, sculptured similarly to face, with lower margin weakly convex. Length of malar space equal to basal width of mandible. Mandible with upper and lower teeth. Antennae with 20 flagellomeres; all flagellomeres longer than wide; first flagellomere 1.3× as long as maximum width, as long as second flagellomere.

MESOSOMA. Mesosoma 1.6× as long as high; mesonotum densely, closely punctate, interspace smooth, without notauli. Scutellum smooth, with distinct lateral carina, distantly punctate. Mesopleuron punctate with longitudinal wrinkles, posteriorly setose. Epicnemial carina distinct, reaching anterior margin of mesopleuron. Propodeum distantly punctate with parallel longitudinal dorsal carinae; spiracles small, elliptical, separated from pleural carinae. Metapleuron smooth only at extreme base rest distinctly longitudinally striate, setose medially rest glabrous, with distinct isolated, longitudinal slit. Fore wing 3.4× as long as wide. Vein 1cu-a distinctly postfurcal. Hind femur 2.2 × as long as its maximum width in lateral view. Hind tibia 3.0× as long as its maximum width. Ratio of length of hind tarsomeres 1–5, 3: 1.5: 1.3: 1: 1.8.

METASOMA. Metasoma coarsely and densely punctate. First metasomal tergite 1.1 × as long as apical width, with distinct dorso-lateral and pair of mid longitudinal carinae, ventro-lateral carina absent. Second metasomal tergite 0.8 × as long as its apical width, with distinct dorso-lateral carina and midlongitudinal carinae. Third metasomal tergite 0.8 × as long as its apical width, with dorso-lateral and midlongitudinal carinae distinct in basal half.

COLOR. Body mostly blackish brown except antennae, face except medially, maxillary and labial palps, fore and mid legs, hind tibiae, tarsi, metasomal sternites, ovipositor sheath yellow.

Male

Unknown.

Distribution

India (Karnataka).

Biology

Unknown.

Figures

Fig. 3. Trieces isolatus sp. nov., holotype, ♀ (AIMB). A. Habitus, lateral view. B. Head, anterior view. C. Head, dorsal view. D. Head, latero-ventral view. E. Head and mesosoma, lateral view. F. Mesosoma, dorsal view.

Fig. 4. Trieces isolatus sp. nov., holotype, ♀ (AIMB). A. Propodeum, dorsal view. B. Fore wing. C. Metasoma, dorsal view. D. Metasoma, lateral view.