Labilochus Khalaim, 2017

Khalaim, Andrey I., Ruiz-Cancino, Enrique & Coronado-Blanco, Juana Maria, 2017, Labilochus brevipalpis, a new genus and species with extremely long mouthparts (Hymenoptera, Ichneumonidae, Tersilochinae) from Mexico, Journal of Hymenoptera Research 55, pp. 121-127 : 122-123

Labilochus Khalaim gen. n.

Type species.

Labilochus brevipalpis Khalaim & Ruíz-Cancino, sp. n.

Composition.

The new genus contains only the type species, L. brevipalpis , described below.

Morphological remarks.

The genus is immediately recognisable by its extremely long glossa and galeae (Fig. 2 ) and reduced number of segments of the maxillary and labial palps. This is the only genus in the subfamily (and probably in the family) having such long glossa and galeae in combination with very short palps. Some taxa of Tersilochinae (e.g. genera Heterocola Förster and Palpator Khalaim, some species of Gonolochus Förster) possess long mouthparts including palps (especially maxillary palp), but none has the long glossa and galeae AND short palps in combination. The formula of maxillary and labial palps (3:2) is also unique within the subfamily; normally tersilochine species have 4-segmented maxillary and 3-segmented labial palps. The new genus is also distinct by having the head almost straight behind the eyes in dorsal view and the occipital carina lacking laterally.

Labilochus belongs to the Tersilochus group of genera, having a right-angled radial cell (Fig. 3 ) and the first metasomal segment with a distinct glymma joining by a deep furrow to the ventral part of the postpetiole. Within this group, Labilochus is most similar to the genus Probles Förster as it has a well-developed foveate groove on the mesopleuron (Fig. 5 ) and a long thyridial depression (Fig. 6 ).

Description.

Head in dorsal view almost straight, weakly tapered behind eyes (Fig. 4 ); temple 0.9 times as long as eye width. Mandible with upper tooth much longer than lower tooth. Clypeus broad, lenticular, almost flat in lateral view, separated from face by weak furrow. Glossa and galeae very long, thin, equal in length, reaching past posterior end of hind coxa (Fig. 2 ); glossa not forked; maxillary palp 3-segmented, labial palp 2-segmented, both are very short (Fig. 2 ). Malar space 0.8 times as long as basal mandibular width in female and 0.5 times in male. Antennal flagellum slightly tapered towards apex, with 21-22 flagellomeres (Fig. 1 ). Occipital carina present dorsally and ventrally (next to mandibular base), absent laterally. Hypostomal carina absent.

Notaulus weakly impressed, without wrinkles. Scutellum with lateral longitudinal carinae developed in its anterior 0.3-0.4 (Fig. 4 ). Foveate groove deep, sharp, with strong transverse wrinkles, strongly oblique, curved, not reaching epicnemial carina anteriorly (Fig. 5 ). Propodeum (Fig. 6 ) with transverse carina well developed, complete; basal area strongly impressed, elongate, distinctly widened anteriorly, 0.35 times as long as apical area, with basal longitudinal carinae indistinct. Propodeal spiracle separated from pleural carina by about 1.5 times diameter of spiracle. Apical area flat, pointed anteriorly; apical longitudinal carinae reaching transverse carina anteriorly, distinct posteriorly and rather weak anteriorly.

Fore wing (Fig. 3 ) with first and second abscissae of radius (Rs +2 r and Rs) meeting at right angle; both abscissae straight. Intercubitus and abscissa of cubitus between intercubitus and second recurrent vein (abscissa of M between 2 rs-m and 2 m-cu) not or weakly thickened. Metacarpus (R 1) not reaching apex of wing. Hind wing with nervellus (cu 1& cu-a) vertical. Legs slender. Hind femur 4.6 times as long as broad and almost 0.85 times as long as tibia. Hind basitarsus 0.45 times as long as tibia (Fig. 2 ).

First tergite slender, postpetiole clearly separated from petiole (Fig. 6 ). Glymma distinct, situated in apical 0.6 of tergite, joining by distinct furrow to ventral part of postpetiole. Thyridial depression deep, about 2.5 times as long as broad (Fig. 6 ). Ovipositor long, evenly upcurved, slender, with very weak dorsal subapical depression; sheath about 3.5 times as long as first tergite.

Etymology.

Named after its extremely long labium. Gender masculine.

Figures

Figures 1 - 6. Labilochus brevipalpis sp. n., holotype female (1, 2, 6) and paratype male (3 - 5). 1 antenna 2 head and mesosoma, lateral view 3 fore wing 4 head and mesosoma, dorsal view 5 mesopleuron 6 propodeum and base of metasoma, dorsal view.