Megalochus grandis Khalaim et Broad

Khalaim, Andrey I. & Broad, Gavin R., 2013, Tersilochinae (Hymenoptera: Ichneumonidae) of Costa Rica, part 2. Genera Megalochus gen. nov. and Stethantyx Townes, Zootaxa 3693 (2), pp. 221-266 : 227-228

Megalochus grandis Khalaim et Broad , sp. nov.

( Figs 20–23 )

This is a most distinctive species of Tersilochinae in the Costa Rican fauna, immediately recognisable by its large and almost entirely dark brown and black body, brownish wings, shortened antenna ( Fig. 20 ), long foveate groove of mesopleuron ( Fig. 22 ), strongly raised subtegular ridge, coarsely and irregularly rugose propodeum and metapleuron ( Fig. 23 ), distinctly clavate hind femur ( Fig. 21 ), and very slender first tergite without glymma ( Fig. 21 ). All specimens were collected in mountainous areas between 1000 and 1700 m altitude. The species seems to be widely distributed through the mountains of the Neotropical region from Costa Rica south to southern Brazil, although it has only rarely been collected. Its host is unknown.

Description. Female. Body length 12.5 mm. Fore wing length 8.25 mm.

Head very strongly rounded behind eyes in dorsal view; temple 0.61× as long as eye width. Mandible densely and coarsely punctate basally, upper tooth distinctly longer than lower tooth. Clypeus very densely punctate in upper 0.7 (distance between punctures shorter than one diameter of puncture), smooth and impunctate in lower 0.3, convex in lateral view. Malar space 0.6× as long as basal width of mandible. Mouthparts with elongate glossa, projecting ventrally by c.0.4× height of head. Flagellum of antenna short, distinctly narrowed towards apex, with 27–36 flagellomeres (30 flagellomeres in holotype); all flagellomeres, except basal and apical ones, distinctly transverse ( Fig. 20 ). Inner eye orbits very weakly convergent ventrally. Face with blunt prominence centrally, very densely punctate, mostly smooth and shining between punctures. Frons and vertex very densely punctate, finely granulate and dull between punctures. Temple distinctly and densely punctate, smooth and shining between punctures. Occipital carina complete. Hypostomal carina absent.

Notaulus as weakly impressed rugulose area. Mesoscutum flattened, very densely punctate (sometimes punctures confused), dull, finely granulate. Scutellum punctate-rugulose, dull, with lateral longitudinal carinae strong, developed in its anterior half. Prepectal carina not joining to anterior margin of mesopleuron, dorsally indistinct ( Fig. 22 ). Foveate groove of mesopleuron long, coarse, crenulate, extending from anterior margin of mesopleuron to base of mid coxa ( Fig. 22 ). Mesopleuron mostly distinctly and densely punctate, with impunctate area above foveate groove in its anterior part, smooth and shining between punctures. Dorsolateral area of propodeum and metapleuron coarsely rugose ( Fig. 23 ). Basal part of propodeum short, 0.35× as long as apical area. Propodeal spiracle round, distance between spiracle and pleural carina equal to about half diameter of spiracle. Apical area flat, transversely wrinkled, anteriorly broadly rounded.

Fore wing with vein 2 m-cu postfurcal, with short unpigmented bulla in its anterior part. Veins Rs +2 r and Rs angled about 125°. Vein 2 rs-m twice longer than abscissa of M between 2 rs-m and 2 m-cu, both these veins not thickened. First abscissa of radius straight, much longer than width of pterostigma. R 1 not reaching apex of fore wing. Hind wing with cu 1& cu-a slightly inclivous or almost vertical.

Hind femur distinctly clavate ( Fig. 21 ), 4.66× as long as broad, and 0.75× as long as tibia. Hind spurs weakly curved at apex.

First metasomal segment very slender, 6.6× as long as posteriorly broad, round in cross-section, entirely smooth, without glymma. Second tergite 3.1× as long as anteriorly broad. Thyridial depression very long, more than 6.0× as long as broad. Ovipositor weakly upcurved, with shallow dorsal subapical depression; sheath almost 1.4× as long as first tergite and 1.58× as long as hind tibia.

Head and mesosoma dark brown to black. Legs and metasoma brown to black. Antenna yellowish brown basally. Wings brown.

Male. Flagellum with 32–36 segments. Malar space about half as long as basal width of mandible. Otherwise similar to female.

Variation. Body length varies from 10.5 to 15.0 mm. The Ecuadorian specimens have the hind femur a little less clavate (i.e. the proximal ‘neck’ of the femur is shorter) and are darker than the Costa Rican and Brazilian specimens. The Brazilian paratype is pale reddish brown on the pronotum, epicnemium and legs.

Etymology. From the Latin grandis (large, great) after its large size.

Material examined. Holotype female (BMNH), Costa Rica, San José Prov., Zurquí de Moravia, on edge of Braulio Carrillo National Park, 1600 m, I.1991, coll. I.D. Gauld.

Paratypes. Costa Rica. Guanacaste Prov.: 1 3 (BMNH) Guanacaste National Park, Estación Mengo (=Cacao), volcano Cacao, 1000 m, 27.II.1988, coll. I.D. Gauld & D. Janzen. 1 Ƥ (INBio) Guanacaste National Park, SE of volcano Cacao, Estación Cacao, 1000–1400 m, IX–X.1990, coll. C. Chaves. Puntarenas Prov.: 1 Ƥ (ZISP) Buenos Aires, Estación Altamira , Sendero Gigantes, 1460 m, VIII–IX.2000, coll. D. Rubí. 1 3 (INBio) Monteverde Nature Reserve, San Luis, 1000–1350 m, IV.1994, coll. Z. Fuentes. Ecuador. Pichincha: 1 Ƥ (BMNH) Nanegal, 1700 m, 28.IV.1990, coll. M. Cooper, BMNH(E) 2005-152. 1 Ƥ (BMNH) Nambillo Valley, near Mindo, 1450 m, 30.VI.1987, coll. M. Cooper, BMNH(E) 2005-152. Brazil. Santa Catarina: 1 Ƥ (BMNH) Nova Teutonia, 27°11ʹ S, 52°23ʹ W, 29.XI.1938, coll. Fritz Plaumann, B.M.1939-181.

Distribution. Costa Rica (Guanacaste, Puntarenas, San José), Ecuador (Pichincha), southern Brazil (Santa Catarina).

Figures

FIGURES 20 – 23. Megalochus grandis sp. nov., Ƥ: 20 — head with antennae, frontal; 21 — hind leg and base of metasoma, left; 22 — mesosoma, left; 23 — propodeum, posterolateral. Scale bars = 0.2 mm.