Gilen, Reshchikov & Achterberg, 2018

Reshchikov, Alexey & Achterberg, Cornelis Van, 2018, The Unicorn exists! A remarkable new genus and species of Perilissini (Hymenoptera: Ichneumonidae) from South East Asia, Acta Entomologica Musei Nationalis Pragae 58 (2), pp. 523-529 : 524

Gilen gen. nov.

Type species. Gilen orientalis sp. nov. by present designation.

Diagnosis. Gilen can be distinguished from other genera of Perilissini by the following combination of character states: produced mid-longitudinal facial projection ( Figs 1A, 1B , 2A ); lower mandibular tooth much longer than upper ( Fig. 1B ); occipital carina incomplete dorsally ( Fig. 2B ), and joined with hypostomal carina at base of mandible ( Fig. 2D ); occiput with distinct concavity ( Fig. 2B ); T1‒3 with slight transverse impressions ( Fig. 1E ); last visible sternites in male with hind margins concave ( Fig. 2E ).

The strong mid-longitudinal facial projection of Gilen is a unique character in the Ichneumonidae . The occipital carina joined with hypostomal carina at base of mandible ( Fig. 2D ), hind wing with cu-a receiving Cu1 far below middle, and concave hind margins of last visible sternites in male ( Fig. 2E ) are characters shared with Lathrolestes Förster, 1869 , Neurogenia Roman, 2010 and Priopoda Holmgren, 1856 . It is therefore assumed that these genera are most likely closely related to Gilen .

Description. Fore wing length 6.8–7.0 mm.

Head. Clypeus flat in lateral view ( Figs 1A , 2A ), its lower margin blunt and more or less bulging apically ( Fig. 1B ). Face (in anterior view) with goblet-shaped mid-longitudinal projection ( Figs 1A, 1B , 2A ), and rather sparsely setose ( Fig. 1B ). Anterior tentorial pit rather large ( Fig. 1B ). Eyes bare ( Figs 1B , 2A ). Lower mandibular tooth much longer than upper ( Fig. 1B ). Occipital carina incomplete dorsally ( Fig. 2B ), ventrally joined with hypostomal carina at base of mandible ( Fig. 2D ). Occiput with distinct concavity ( Fig. 2B ).

Mesosoma. Epomia absent ( Fig. 2C ). Notauli very shallow and indistinct ( Fig. 2B ). Mesopleuron with sternaulus-like impression ( Fig. 2C ). Epicnemial carina distant from anterior margin of mesopleuron (2C). Propodeum in lateral profile convexly rounded ( Fig. 1A ), with carinae complete except for area basalis, which is absent (fused with area superomedia) ( Fig. 1C ). Forewing with areolet petiolate ( Fig. 1A ). Pterostigma receiving vein Rs+2r at its basal 0.35. Vein 2m-cu with a single bulla. Hind wing with cu-a receiving Cu1 well below middle. Tarsal claws strongly pectinate ( Fig. 1D ). Fore tibia with apical tooth.

Metasoma distinctly and densely punctate, sparsely setose. T1 as long as broad with dorsal longitudinal carina defined. Glymma deep. T1‒3 with slight transverse impression. Ovipositor sheath flat, not longer than depth of metasomal apex. Ovipositor straight, with a long, shallow, subapical dorsal notch. Last visible sternites in male with hind margin concave ( Fig. 2E ). Parameres broad and short ( Fig. 2E ).

Differential diagnosis. See Key and Discussion below.

Etymology. The generic name ʻ Gilen ʼ refers to a mythical single horned creature (Thai name: กเลน) known in Thai and other Asian cultures. It refers to the unique mid-longitudinal facial projection. The gender is masculine.

Species included. The genus is described as monotypic.

Figures

Fig. 1. Gilen orientalis sp. nov., holotype ♀. A – lateral habitus; B – face; C – propodeum; D – tarsal claw; E – metasomal tergites dorsally.

Fig. 2. Gilen orientalis sp. nov., holotype ♀ (except E – paratype ♁). A – head laterally; B – head and mesosoma dorsally; C – mesopleuron; D – head ventrally with occipital carina joined hypostomal carina at base of mandible; E – distal sternites of male.