Benyllus mesonotator, Riedel, 2023

Riedel, Matthias, 2023, Contribution to the knowledge of the Ichneumoninae (Hymenoptera, Ichneumonidae) from Maritime Southeast Asia, Zootaxa 5363 (1), pp. 1-94 : 26-28

Benyllus mesonotator nov. sp.

( Figs 9A–E )

Holotype. (♀) Malaysia: SW Sabah, nr Long PA Sia (West), c 1010 m, 25.xi.–8.xii.1987, Mal. trap 1 b, RMNH´87, C. van Achterberg (Leiden).

Paratypes. (♂) similar label (coll. Riedel); (♂) Malaysia: SE Sabah, nr. Danum Valley Field C, Malaise trap 1, c 150 m, 14–20.iii.1987, C. van Achterberg, RMNH´87 (Leiden); (♂) Indonesia: N Sumatra, Ketambe , c 400 m, near N.P. Gn. Leuser, Mal. trap, 7.iii–15.iv.1994, Y. van Nierop & C. van Achterberg, RMNH´95 (Leiden) .

Etymology. The species name refers to the mesoscutum having two paramedian ivory stripes.

Description. ♀. Body length 9.3 mm.

Head. Flagellum with 40 flagellomeres, moderately lanceolate; 1 st flagellomere 3.4 × longer than wide, about 14 th flagellomere square, widest flagellomeres 1.6 × wider than long. Temple very short, strongly and roundly narrowed behind eye (fig. 9B). OED 1.1 × and OOD 1.2 × ocellar diameter. Frons transversely rugose-punctate dorsally. Face densely punctate, shining, slightly impressed above anterior tentorial pits and slightly swollen ventro-laterally. Clypeus almost flat, with sparse punctures apically; apical margin sharp and straight (fig. 9A). Mandible long and distinctly narrowed behind base, with two teeth, ventral tooth smaller than dorsal tooth. Malar space 1.2 × as long as width of mandibular base. Gena with dense punctures. Genal carina reaching hypostomal carina close to mandibular base.

Mesosoma . Notaulus indistinct. Mesoscutum densely rugose-punctate, dull. Mesopleuron and metapleuron rugose-punctate; speculum smooth; juxtacoxal carina present. Scutellum slightly elevated and slightly longer than wide, rugose-punctate; lateral carina complete, not extended or raised apically. Propodeum completely carinated (fig. 9C), with distinct apophysis; spiracle slit-shaped. Area superomedia heart-shaped, 1.2 × longer than wide; costula reaching at apical 0.6 of its length. Hind coxa with fine dense punctures, without scopa. Hind femur densely punctate, 4.4 × longer than wide. Claws simple. Areolet pentagonal, frontal distance between veins 2rs-m and 3rs-m 4.0 × their diameter. Vein 1cu-a slightly antefurcal by 1.0 × its width.

Metasoma. Oxypygous. Petiole about as wide as high. Postpetiole distinctly widened, without latero-median carina, densely punctate; median field not separated. Gastrocoelus weakly impressed, with fine ridges. Thyridium small, slightly transverse, 0.2 × as wide as the interval between thyridia (fig. 9D). 2 nd tergite 1.2 × wider than long, densely rugose-punctate. 3 rd tergite finely rugose-punctate; 4 th tergite with superficial punctures apically. Ovipositor sheath narrow, reaching widely behind metasomal apex by combined length of 6 th and 7 th tergite (fig. 9E).

Colour. Black. Flagellum with ivory ring on flagellomeres 5–17. Ivory are palps, base of mandible, clypeus except brownish spot medially, face except M-shaped black median spot, gena and outer orbit, frontal orbit up to lateral ocellus, frontal and upper margins of pronotum, subtegular ridge, two short paramedian stripes on mesoscutum, spot on ventral mesopleuron, prescutellar ridge, apical scutellum and postscutellum, upper division and apical spot on metapleuron, spot in front of propodeal spiracles, posterolateral stripes on propodeum, apical bands of all tergites (shortly interrupted medially on 3 rd and 4 th tergites), fore and mid coxae and trochanters, dorsal spots on hind coxa and trochanter and entire hind tarsus. Legs reddish; hind femur black in apical 0.3; hind tibia yellowish, black in basal 0.1 and apical 0.3. Wings hyaline; pterostigma dark brown.

♂. Body length 7.2–9.4 mm. Flagellum with 35–38 flagellomeres; 1 st flagellomere 3.1–3.3 × longer than wide. Tyloids on flagellomeres 10/11–17/18, long-oval to linear, maximally 0.8 × as long as their flagellomeres. OED 1.0 × and OOD 1.1 × ocellar diameter. Scutellum ± pyramidal, rugose-punctate, with complete, slightly lamelliform lateral carina. Hind femur 4.1–4.7 × longer than wide. 2 nd tergite 1.3–1.4 × wider than long. Hypopygium unmodified; its apical margin rounded. Structure otherwise as described for the ♀.

Colour. As in ♀, but differs by: ivory rings on flagellomeres 8–15; tyloids yellowish. Face entirely ivory; gena sometimes black; scape ivory ventrally. Mesoscutum with paramedian stripes in the ♂ from Sumatra, but with weak reddish paramedian spot in the ♂♂ from Borneo. Area spiracularis of propodeum black. Postpetiole with apical ivory band; 2 nd and 3 rd tergites with posterolateral ivory spots; 6 th and 7 th tergites and paramere entirely ivory. Hind femur red basally, ± infuscate centrally and apically.

Remarks. This new species resembles Benyllus egregiscutellatus Heinrich , but differs by the ivory paramedian stripes on mesoscutum, entirely black area petiolaris and black hind tarsus in ♀. The scutellum is rounded in the ♀, but ± pyramidal in the available ♂♂. It might represent a subspecies of B. egregiscutellarus .

Distribution. Borneo and Sumatra.

Figures

FIGURE 9. Benyllus mesonotator n. sp. A face of HT ♀, frontal view, B head of ♂, dorsal view, C propodeum of HT ♀, dorsal view, D basal tergites of HT ♀, dorsal view, E metasoma of HT ♀, dorso-lateral view.