Plectiscus taitaensis Varga, 2024

Varga, Oleksandr, 2024, Two new species of the genus Plectiscus Gravenhorst, 1829 (Hymenoptera, Ichneumonidae: Orthocentrinae) from Kenya, Zootaxa 5453 (2), pp. 291-297 : 294

Plectiscus taitaensis Varga , sp. n. ( Fig. 2 )

LSID urn:lsid:zoobank.org:act:CDEB9B26-875C-4022-9775-4B4B3864B4F2

Material examined. Holotype: ♀, KENYA: Coast Prov., Taita Hills, Ngangao Forest , 3.36100º S, 38.34186º E, 1848 m, Malaise trap, indigenous forest, 24.01– 07.02.2012, leg. R. Copeland (deposited in: ICIPE) . Paratype: ♀, Eastern Prov. , Nyambene Hills, Itieni Forest, at bottom, 2142 m, 0.24433º N, 37.87016º E, Malaise trap, edge of indigenous forest, nr. forest station, 10– 24.07.2011, leg. R . Copeland (deposited in: ICIPE) . Other material: ♂, the same locality as holotype, but 10– 24.01.2012 (deposited in: ICIPE) .

Diagnosis. Plectiscus taitaensis sp. n. is characterized by the combination of the following characters: body generally brown ( Fig. 2A ); antenna with 22 flagellomeres, first flagellomere 3.0× as long as wide; temples short and strongly narrowed behind eyes, straight (dorsal view) ( Fig. 2D ); epicnemum with a short fold, but lacking a developed carina ( Figs 2G , 3B ); propodeum with only lateral longitudinal carina present on the posterior half of the propodeum ( Figs 2H , 3C ); fore wing with vein 2 rs-m about as long the distance between 2 rs-m and 2 m-cu; vein 3rs-m absent; hind wing with nervellus not intercepted, strongly reclivous ( Fig. 2F ); first tergite 2.0× as long as posterior width, longitudinally striate; second tergite 0.9 (male)–1.2× as long as posterior width, longitudinally striate anteriorly ( Figs 2I , 3C ).

Plectiscus taitaensis sp. n. is similar to P. pomariorum , but differs in having antenna with 22 flagellomeres (16–17 in P. pomariorum ) and a more weakly sculptured second metasomal tergite.

Description. Female. Holotype ( Fig. 2 ). Body length approximately 4.5 mm. Fore wing 3.2 mm.

Head ( Figs 2B–E ) smooth and sparsely pubescent. Antenna with 22 flagellomeres, first flagellomere 3.0× as long as wide. Face about 0.7× as long as wide, sparsely and indistinctly sculptured; eyes weakly divergent to clypeus. Malar space 1.9× basal width of mandible; subocular sulcus distinct. Clypeus 0.6× as long as wide, convex centrally. Mandible bidentate, strongly bent outward; lower tooth small and hardly visible. Temples short and strongly narrowed behind eyes, straight (dorsal view). Frons and vertex smooth; length of the ocellar-ocular distance about 1.0× maximum diameter of lateral ocellus; occipital carina absent.

Mesosoma ( Figs 2C–D, F–H ) generally smooth. Propleuron sparsely pubescent. Pronotum smooth, with traces of carinulation anteriorly. Mesoscutum densely pubescent; notauli absent. Scutellum densely pubescent, with carinae present only on anterior 0.1. Mesopleuron smooth, with a short fold where epicnemial carina would reach anterior edge of mesopleuron; epicnemial carina absent. Metapleuron smooth; pleural and submetapleural carinae present. Propodeum smooth anteriorly, sparsely and indistinctly sculptured posteriorly, with only lateral longitudinal carina present on posterior half of propodeum.

Legs relatively stout; hind femur 3.4× as long as wide, third tarsomere of hind tarsus about as long as fifth tarsomere; tarsal claws simple.

Wings ( Fig. 2F ). Fore wing with vein 2 rs-m about as long as distance between 2 rs-m and 2 m-cu; vein 3rs-m absent; vein 1cu-a weakly postfurcal to M & Rs; hind wing with nervellus not intercepted, strongly reclivous.

Metasoma ( Fig. 2I ) longitudinally striate anteriorly and sparsely pubescent. First tergite 2.0× as long as posterior width, longitudinally striate; carinae hardly visible among striation; lateral oblique grooves distinct. Second tergite 1.2× as long as posterior width, weakly longitudinally striate anteriorly, with deep basolateral grooves. Remaining part of metasoma smooth, compressed laterally. Ovipositor sheath about 0.9× as long as hind tibia, apical part widened and pubescent.

Colour. Body generally brown except antenna underside, face narrowly below antennal sockets, mandible (except apices), and legs (except hind coxae) yellowish. Hind coxa brownish, but paler than body.

Male. Generally resembles female ( Fig. 3 ), but has antenna with 18 flagellomeres and slightly shorter metasomal tergites. This male was collected in the same locality as the holotype, but due to the poor condition of the specimen I have not included the specimen as a paratype.

Etymology. The new species is named after the type locality situated in Taita Hills.

Distribution. Kenya.

Figures

FIGURE 2. Plectiscus taitaensis Varga, sp. n., holotype female. A—Lateral view of habitus; B—Frontal view of face; C— Lateral view of head and mesosoma; D—Dorsal view of head and mesoscutum; E—Dorsal view of mandible. Lower (internal) teeth arrowed with red; F—Wings; G—Frontal view of epicnemium. Fold arrowed with red; H—Dorsal view of propodeum; I—Dorsal view of metasomal tergites 1–2.

FIGURE 3. Plectiscus taitaensis Varga, sp. n., male.A—Lateral view of habitus; B—Lateral view of mesosoma. Fold arrowed with red; C—Dorsal view of propodeum and metasomal tergites 1–2.