Tetractenion ibayaensis Reynolds Berry & van Noort, 2020

Berry, Terry Reynolds & Noort, Simon van, 2020, Revision of the endemic Afrotropical genus Tetractenion (Hymenoptera, Ichneumonidae) with an identification key to genera of Banchinae for the region, ZooKeys 1007, pp. 49-84 : 49

Tetractenion ibayaensis Reynolds Berry & van Noort sp. nov. Fig. 2

Type material.

Holotype ♀: Tanzania, Mkomazi Game Reserve, Ibaya Camp, north west side, 3°57.91'S, 37°48.09'E, 22-24 April 1996, S. van Noort, Acacia/Commiphora/Combretum bushland, Yellow P. Trap, SAM-HYM-P019172 (SAMC).

Differential diagnosis.

Tetractenion ibayaensis is immediately distinguishable from other Tetractenion species by having a largely fulvous body and a white face, with the occiput, gena and metasomal tergites IV-VIII dark brown to black, and the hind tibia and tarsus infuscate. The clypeal and mandibular setae are long. The metasoma is hardly laterally compressed with metasomal tergite I stout, being about as long as wide. Pits on the mesopleuron and propodeum are visibly large and deep. In addition, the clypeus is hardly apically invaginated and the propodeal spiracle is distinctly circular and not circular-elliptical as in the other species.

The head is rounded behind the eyes distinguishing the species from T. acaule and T. pascali . The pronotal collar is no more than a wrinkle, separating the species from T. acaule and T. rosei . Pectinate tarsal claws on the hind legs separates the species from T. acaule and T. luteum . Metasomal tergites II and III are quadrate separating the species from all other Tetractenion species except T. acaule where tergites II and III are sometimes subquadrate and quadrate, respectively; and T. luteum where tergite III is quadrate. Sparse microtrichia on the wings distinguishes T. ibayaensis from T. luteum and T. pascali , and the pterostigma is brown separating the species from T. luteum , T. pascali , T. rosei , and T. pseudolutea .

Description.

Body mostly fulvous; tibia and tarsus III brown; metasomal tergites IV-VIII brown to nearly black; head with face and area around eyes white; frons and occiput dark brown to near black; mandibles yellow with base and tips brown. Sparse microtrichia on wings, venation and pterostigma brown.

Head rounded behind eyes; occiput deeply and angularly excavated, occipital carina strong, extending to lower gena at mandibular base; malar space half as long as mandibular basal width; eyes very large; face and clypeus finely and evenly punctate on a shiny background; face with three lobes, tentorial pits deep; clypeus small, laterally convex with declivity, apically invaginated, clypeal edge convex; mandibular teeth triangular, lower tooth longer than upper tooth; clypeal and mandibular setae long; antenna long, slender and apically tapered.

Mesosoma stout and deeply punctate on a shiny background; mesopleuron higher than wide, epicnemial carina ending at anterior edge of mesopleuron; deep pits on the mesopleuron and propodeum; pronotum moderately punctate on a shiny background with no more than a wrinkle on collar; mesososcutal lobes hardly present on mesoscutum, notauli posteriorly meeting before reaching the scutellum; propodeum weakly convex, posteriorly confluently grading into weak transverse wrinkles, posterior transverse carina indistinct, lateral longitudinal carinae reduced, spiracle small and circular.

Metasoma with tergite I stout, tapered anteriorly, not distinctly dorso-ventrally compressed in medial region, glymma present, spiracle positioned in front of middle and protruding, especially dorsally, hardly punctate dorso-laterally, metasoma indistinctly punctate beyond and shining; gastrocoeli on tergite II indistinct; tergites II and III quadrate, tergites IV-VIII only slightly higher than wide.

Fore wing without ramellus on Rs-M vein; areolet large and quadrate with a short stalk receiving 2m-cu at center. Hind wing with Cu1 shorter than cu-a such that Cu2 arises above the middle of these combined veins. Legs very long; hind femur reaching beyond metasomal apex, length of tibia III plus tarsus III as long as body; spurs of tibia III longer than half metatarsal length; tarsal claws pectinate.

CT 2.1; ML 0.5; IO 1.6; OO 1.6; Fl1 4.3; OT 0.2; B 8.1 mm; A 8.1 mm; F 6.4 mm.

Etymology.

Named after the type locality. Noun in apposition.

Distribution.

Tanzania.

Figures

Figure 2. Tetractenion ibayaensis sp. nov. Holotype A habitus, lateral view B habitus, dorsal view C head, anterior view D wing (inset: data labels).