Gelanes horstmanni Khalaim, 2017

Khalaim, Andrey I. & Ruiz-Cancino, Enrique, 2017, Ichneumonidae (Hymenoptera) associated with xyelid sawflies (Hymenoptera, Xyelidae) in Mexico, Journal of Hymenoptera Research 58, pp. 17-27 : 18-20

Gelanes horstmanni Khalaim sp. n.

Figs 1-5

Comparison.

The new species is immediately distinguished from the 13 Nearctic species described by Horstmann (2013) by the combination of the filiform flagellum comprising 25 flagellomeres (Fig. 2 ) and the ovipositor bearing a deep and narrow dorsal subapical notch (Fig. 5 ). Only two Nearctic species, G. incisus Horstmann and G. punctipleuris Horstmann, possess similar ovipositors with a narrow dorsal subapical notch, but in both species the genae are much shorter (0.6-0.7 times as long as eye width) and more strongly constricted behind the eyes, the clavate flagellum comprises only 16-18 flagellomeres, and the apex of the ovipositor bears one or several fine teeth ventrally. In the key to Nearctic species ( Horstmann 2013), G. horstmanni runs to couplet 14, but does not correspond with either side of the couplet as it has the mesopleuron punctate with smooth interspaces, a weak foveate groove, and an extremely long ovipositor with the sheath being more than 4.5 times as long as the first tergite. Gelanes horstmanni also differs from all of its Palaearctic congeners by the head strongly prominent behind the eyes in dorsal view (Fig. 3 ).

Description.

Female. Body length 5.0 mm. Fore wing length 3.9 mm.

Head prominent, strongly rounded behind eyes in dorsal view (as in Fig. 3 ); gena 0.85 times as long as eye width. Ocellar index 1.7. Clypeus broad and short, 5.5 times as broad as long (Fig. 4 ), flat in lower half, with lower margin almost straight. Mandible with upper tooth subequal in length and size to lower tooth; both teeth with apices widely rounded, probably obliterated because of use (Fig. 4 ). Malar space almost 0.9 times as long as basal mandibular width. Antennal flagellum (Fig. 2 ) filiform, long, with 25 flagellomeres; flagellomeres 1-3 rather short, slightly elongate; second flagellomere is the shortest; flagellomeres 4 and following 1.2-1.3 times, subapical flagellomeres almost 1.1 times as long as broad; flagellomeres 4-6 bearing distinct and flagellomere 7 weak finger-shaped structures at apex on outer surface. Face with moderately strong prominence medially. Face and frons distinctly punctate, with smooth interspaces between punctures centrally, finely and densely punctate with granulate and dull interspaces peripherally. Vertex distinctly punctate, smooth between punctures. Gena smooth, upper part with moderately dense and fine punctures, lower part with very fine and sparse punctures. Occipital carina complete. Hypostomal carina completely absent.

Mesoscutum and scutellum with moderately dense fine punctures, polished between punctures. Scutellum with lateral longitudinal carinae present only at extreme base. Notaulus very weak, slightly impressed, with few fine oblique striae somewhat distant from anterolateral margin. Mesopleuron with shallow fine punctures, more or less smooth and weakly shining between punctures centrally, finely granulate peripherally. Foveate groove rather shallow, short, oblique, situated somewhat before centre of mesopleuron, with fine transverse wrinkles. Basal area of propodeum indistinct, moderately broad, rectangular, about 2.5 times as long as broad and 0.4 times as long as apical area. Dorsolateral area with fine, scattered punctures, interspaces between punctures smooth centrally. Distance between propodeal spiracle and pleural carina about as long as diameter of spiracle. Apical area centrally indistinctly punctate with interspaces between punctures more or less smooth, periherally uneven, flat, widely rounded anteriorly; apical longitudinal carinae well developed, reaching transverse carina anteriorly.

Fore wing with second recurrent vein (2 m-cu) postfurcal. Intercubitus (2 rs-m) moderately thick, somewhat longer than abscissa of cubitus between intercubitus and second recurrent vein (abscissa of M between 2 rs-m and 2 m-cu). First abscissa of radius (Rs +2 r) straight, distinctly longer than width of pterostigma. First and second sections of radius (Rs +2 r and Rs) meeting at right angle. Metacarpus (R 1) short, running about half way from distal end of Rs and apex of fore wing. Postnervulus (Cu &2 cu-a) intercepted distinctly below its middle. Hind wing with nervellus (Cu 1& cu-a) vertical.

Legs slender. Hind femur 0.65 times as long as tibia (Fig. 1 ). Hind basitarsus short, 0.4 times as long as hind tibia. Spurs of hind tibia short and straight. Tarsal claws not pectinate.

First tergite moderately slender, 2.6 times as long as broad posteriorly, dorsally polished, laterally striate before glymma, smooth at base. Glymma deep, situated slightly proximal of centre of first tergite, joining strong furrow to ventral part of postpetiole. Second tergite 1.25 times as long as broad anteriorly. Thyridial depression slightly elongate. Ovipositor very long, evenly upcurved, with a deep dorsal subapical notch, without teeth ventrally (Fig. 5 ); sheath over 4.5 times as long as first tergite and about 3.0 times as long as hind tibia.

Head, mesosoma and first metasomal segment black. Palpi, mandible (except black teeth), clypeus and tegula yellow. Antennal flagellum black, scape and pedicel brown ish black. Pterostigma dark brown. Fore and mid legs brownish yellow, tarsi slightly infuscate, mid coxa on outer half dark brown. Hind leg with coxa brownish black, femur predominantly brown (paler apically), trochanters and tibia yellow-brown, tarsus infuscate. Metasoma behind first tergite yellow ventrally, brown to dark brown laterally, brownish black dorsally.

Male. Flagellum slightly tapered towards apex, with 24-25 flagellomeres. Head rather strongly prominent behind eyes in dorsal view (Fig. 3 ). Malar space 0.3-0.5 times as long as basal mandibular width. One male with mandibular teeth not obliterated, pointed, subequal in length. Clypeus more or less lenticular, with lower margin weakly convex. Basal area of propodeum narrow, almost as long as apical area. Distance between propodeal spiracle and pleural carina 1.0-2.0 times as long as diameter of spiracle. Tergites 1 and 2 of metasoma more slender. Metasoma posterior to tergite 1 dark brown, subcylindrical. Otherwise similar to female.

Variation.

Six males are not included to the type series; they are somewhat smaller, with the gena not prominent behind eyes in dorsal view and the body highly smooth and less punctate.

Etymology.

The species name in dedicated to the late Klaus Horstmann, a German expert in Ichneumonidae , in recognition of his contribution to the study of Nearctic Tersilochinae .

Material examined.

Holotype female (UNAM), Mexico, Tlaxcala, Nanacamilpa, Ejido Los Búfalos, N 19°28', W 98°35', bosque Pino-Encino ( Pinus + Quercus forest), 2830-2900 m, Malaise trap, 4.IV-3.V.2016, coll. Y. Marquez & A. Contreras.

Paratypes. 3 males (BMNH, UNAM, ZISP), same data as holotype .

Non-type material.

6 males (1 in BMNH, 4 in UNAM, 1 in ZISP), same data as holotype.

Distribution.

Central Mexico (Tlaxcala).

Figures

Figures 1 - 7. Gelanes horstmanni sp. n., holotype female (1, 2, 4, 5) and paratype male (3). 1 body, lateral view 2 head with antenna and mesosoma, dorso-lateral view 3 head, dorsal view 4 head, antero-ventral view 5 apex of ovipositor, lateral view. Idiogramma comstockii, female 6 head, antero-ventral view 7 head, dorso-lateral view.