Stethantyx covida Khalaim & Ruiz-Cancino, 2020

Khalaim, Andrey I. & Ruiz-Cancino, Enrique, 2020, Contribution to the taxonomy of Mexican Tersilochinae (Hymenoptera, Ichneumonidae), with descriptions of five new species, ZooKeys 974, pp. 1-21 : 1

Stethantyx covida Khalaim & Ruiz-Cancino sp. nov. Figures 21-26

Differential diagnosis.

The new species differs from other species of Stethantyx with a right-angled first and second abscissae of radius (Rs+2r and Rs) by the combination of highly polished head and mesosoma, sharp and strongly oblique foveate groove of mesopleuron (Fig. 23 ), propodeum with narrow basal area (Fig. 24 ), and very long and slender ovipositor (Fig. 21 ). It is very similar to St. oaxacana sp. nov., but differs from this species by the shape of the ovipositor (Fig. 26 ), and somewhat longer gena, thyridial depression and second tergite.

Description.

Female. Body length 3.5 mm. Fore wing length 2.8 mm.

Head, in dorsal view, roundly constricted posterior to eyes; gena 0.9-1.0 × as long as eye width. Eyes glabrous. Clypeus lenticular (sometimes with lower margin slightly truncate), 3.2-3.4 × as broad as long, weakly convex in lateral view, with weak transverse ridge in lower 0.3-0.4, separated from face by sharp furrow; smooth, with fine punctures in upper part. Mandible slender, distinctly constricted in basal 0.3-0.4; upper tooth 2.0-2.5 × as long as the lower. Malar space 0.9-1.1 × as long as basal mandibular width. Antennal flagellum (Fig. 22 ) with 15-18 flagellomeres, filiform; flagellomeres 2-4 ca. 1.4-1.8 ×, subapical flagellomeres 1.1-1.3 × as long as broad; flagellomeres 4 to 6 bearing subapical finger-shaped structures on outer surface (hardly discernible in light microscope). Face weakly convex. Face, frons, and vertex subpolished; face and frons with very fine (sometimes indistinct) punctures. Gena polished, impunctate, or with very fine punctures in posterior part (near occipital carica). Occipital carina complete, evenly arcuate in dorsal view. Hypostomal carina present, complete.

Mesoscutum and mesopleuron very finely (sometimes indistinctly) punctate on smooth background; dorsolateral area of propodeum polished, impunctate. Notaulus with strong wrinkle on anterolateral side of mesoscutum. Scutellum with lateral longitudinal carinae at basal 0.3-0.5. Epicnemial carina not reaching front margin of mesopleuron, continuing above along front margin of mesopleuron, and vanishing there (Fig. 23 ). Foveate groove situated in anterior half of mesopleuron, deep, strongly oblique, almost straight, with distinct transverse wrinkles (Fig. 23 ). Propodeal spiracle small, adjacent to pleural carina or separated from it by one diameter of spiracle (Fig. 23 ). Propodeum with long and narrow basal area (basal longitudinal carinae parallel or weakly divergent anteriorly) which is 0.5-0.8 × (0.6 in holotype) as long as apical area (Fig. 24 ). Apical area flat, rounded to slightly pointed anteriorly; apical longitudinal carinae complete and reaching transverse carina anteriorly.

Fore wing with second recurrent vein (2m-cu) postfurcal, weakly pigmented in anterior part and distinct posteriorly. First abscissa of radius (Rs+2r) straight, longer than width of pterostigma. First and second abscissae of radius (Rs+2r and Rs) meeting at right or slightly acute angle. Intercubitus (2rs-m) slightly thickened, relatively long, distinctly longer than abscissa of cubitus between intercubitus and second recurrent vein (abscissa of M between 2rs-m and 2m-cu). Metacarpus (R1) short, not reaching apex of fore wing (Fig. 21 ). Second abscissa of postnervulus (Cu&2cu-a) present, thus brachial cell is closed posteriorly. Hind wing with nervellus (cu1&cu-a) weakly reclivous. Legs slender. Tarsal claws not pectinate.

First tergite 4.0 × as long as posteriorly broad, smooth, usually with longitudinal striae laterally before glymma and dorsally at apex of petiole; petiole slightly trapeziform in cross-section centrally; in dorsal view, postpetiole distinctly widened at base, wider than petiole and clearly separated from it; in lateral view, upper margin of tergite straight or weakly arcuate in basal 0.6-0.7 and arcuate in apical 0.3-0.4. Glymma (Fig. 25 ) small but distinct, situated in apical 0.55 of tergite and joining by fine groove (sometimes indistinct in small specimens) with lower part of postpetiole. Second tergite ca. 1.7 × as long as anteriorly broad. Thyridial depression deep, 2.0-3.0 × as long as broad, with posterior end usually rounded. Ovipositor bent upwards over its total length, with weak dorsal subapical depression and without teeth ventrally (Fig. 26 ); sheath 2.7-3.5 × (3.2 in holotype) as long as first tergite.

Head, mesosoma and first tergite brownish black to black; clypeus brownish yellow in lower 0.4 and dark brown in upper part, but sometimes clypeus is more or less entirely brownish yellow. Palpi and mandible (teeth red) brownish yellow. Tegula brownish yellow to brown. Antenna dark brown to black, scape and pedicel sometimes yellow-brown ventrally. Pterostigma brown. Legs brownish yellow; coxae and trochanters sometimes strongly darkened with brown (to almost black), tibiae and tarsi sometimes weakly to strongly infuscate (Fig. 21 ). Metasoma entirely or predominantly dark brown, sometimes brown posteriorly and ventrally.

Male. Similar to female but malar space somewhat shorter than basal mandibular width; basal area of propodeum very narrow and usually longer; and second metasomal tergite and thyridial depression longer.

Variation.

Two females from Nevado de Toluca (State of Mexico) possess second tergite 1.5-1.6 × as long as anteriorly broad. Epicnemial carina sometimes almost reaching front margin of mesopleuron. Foveate groove in small specimens sometimes weak.

Etymology.

This abundant Mexican species is named after the Covid-19 (Coronavirus) because the taxon was described while the outbreak of this virus in Mexico.

Material examined.

Holotype female (UAT), Mexico, Tamaulipas, 6 km NE of Miquihuana, 23°36.125'N, 99°42.45'W, 2200-2600 m, 24.X.2008, coll. A.I. Khalaim.

Paratypes. Mexico: 5 females (2 in BMNH, 1 in UAT, 2 in ZISP), same data as holotype. 12 females, 1 male (10 females in UAT; 2 females, 1 male in ZISP), Tamaulipas, [NE of] Miquihuana, Km. 15 [of road] from La Peña, 2500 m, pine forest, 16.VIII.2000, coll. D.R. Kasparyan. 14 females (1 in BMNH, 1 in FSCA, 12 in UAT), Tamaulipas, [NE of] Miquihuana, Km. 21 [of road] La Peña - Joya, pine forest, 16.IX.2000, coll. C. Covarrubias Dimas. 1 female (UAT), Tamaulipas, [NE of] Miquihuana, Km. 13 [of road] Aserradero - La Peña, herbs, 28.VIII.1993, coll. E. Ruíz-Cancino. 1 female (UAT), Tamaulipas, [NE of] Miquihuana, Km. 18 [of road] La Peña - Aserradero, pine forest, herbs, 24.X.2008, coll. E. Ruíz-Cancino. 1 female (ZISP), Hidalgo, 8 km N of Pachuca de Soto, National Park El Chico, 20°11.4'N, 98°44.55'W, 2950-3000 m, 27.III.2014, coll. A.I. Khalaim. 2 females (BMNH, FSCA), Hidalgo, 8 km N of Pachuca de Soto, National Park El Chico, 20°11.4'N, 98°44.55'W, 2800-2900 m, 18-22.XII.2014, coll. A.I. Khalaim. 2 females, 1 male (1 female, 1 male in UAT; 1 female in ZISP), Tlaxcala, 15 km SSE of Apizaco, north slope of La Malinche volcano, 19°16.97'N, 98°02.52'W, 3300-3800 m, 2.IV.2016, coll. A.I. Khalaim. 7 males (1 in BMNH, 1 in FSCA, 4 in UAT, 1 in ZISP), Tlaxcala, 15 km SSE of Apizaco, north slope of La Malinche volcano, 2550-3000 m, 1-2.X.2016, coll. A.I. Khalaim & A.E. Humala. 2 females, 1 male (UAT), Mexico [State of], NW slope of Nevado de Toluca volcano, 3150-3830 m, 29.IX.2016, coll. A.I. Khalaim. 1 female, 1 male (ZISP), Morelos, N of Tepoztlán, path to El Tepozteco, 1800-2000 m, 11.X.2014, coll. A.I. Khalaim. 2 males (TAMU), Guerrero, 7 mi. SW of Filo de Caballo, 12.VII.1985, coll. J. Woolley & G. Zolnerowich. 1 female (TAMU), Oaxaca, Llano de las Flores, 8900 ft (= 2715 m), 17-19.VII.1987, coll. R. Wharton. 2 females (TAMU), Oaxaca, 15 mi. (= 24 km) NE of Ixtlán de Juárez, Llano de las Flores, 21.VII.1985, coll. J.B. Woolley & G. Zolnerovich. 1 female (TAMU), Oaxaca, 10.8 mi. (= 17.4 km) S of El Punto, 6100 ft (= 1860 m), 19.VII.1987, coll. R. Wharton. 1 female (UNAM), Oaxaca, Santiago Comaltepec, 17.58429N, 96.49398W, 2332 m, 6.VI.2009, coll. H. Clebsch & A. Zaldívar. 1 female (UAT), 1 male (UNAM), same data but 29.XI-26.XII.2005 (head in female absent). 6 females, 12 males (5 females, 11 males in UNAM; 1 female, 1 male in UAT), Oaxaca, Santiago Comaltepec, 17.58424N, 96.49428W, 2427 m, humid oak-pine forest, Malaise trap, 12-20.VI.2007, coll. H. Clebsch. Guatemala: 1 female (UCR), Sacatepéquez [Department], Sumpango, Durwest Farm, 14°40'17"N, 90°43'11"W, 3-10.II.2007, coll. M. Hoddle.

Distribution.

Northeast, central, and south Mexico (Tamaulipas, Hidalgo, Tlaxcala, Mexico, Guerrero, Oaxaca), Guatemala.

Figures

Figures 21 - 26. Stethantyx covida sp. nov., holotype female 21 habitus, lateral view 22 head with antennae, dorso-posterior view 23 head and mesosoma, lateral view 24 propodeum and first tergite, dorso-posterior view 25 first tergite, lateral view 26 apex of ovipositor, lateral view.