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Revista mexicana de biodiversidad

versión On-line ISSN 2007-8706

Rev. Mex. Biodiv. vol.83 no.2 México jun. 2012

 

Taxonomía y sistemática

 

Mexican species of Exetastes (Hymenoptera: Ichneumonidae: Banchinae), with description of three new species

 

Especies mexicanas de Exetastes (Hymenoptera: Ichneumonidae: Banchinae), con la descripción de tres especies nuevas

 

Andrey I. Khalaim1, 2 * and Enrique Ruiz–Cancino1

 

1 División de Estudios de Postgrado e Investigación, Facultad de Ingenieria y Ciencias, Universidad Autónoma de Tamaulipas, 87149 Cd. Victoria, Tamaulipas, Mexico.

2 Zoological Institute, Russian Academy of Sciences, Universitetskaya nab. 1, St.Petersburg 199034, Russia. *ptera@mail.ru.

 

Recibido: 26 septiembre 2011
Aceptado: 8 noviembre 2011

 

Abstract

Twenty one species and subspecies of Exetastes Grav. are recorded from Mexico. Exetastes arteagus sp. nov., E. gauldi sp. nov. and E. lascivus sp. nov. are described as new. Exetastes pasculus Gauld et Ugalde is recorded for the first time for Mexico. New data on distribution in Mexico and a key to the Mexican species of Exetastes are provided. The known Mexican fauna is closer to the Nearctic fauna than to the Costa Rican fauna: 13 out of 21 Mexican species and subspecies (62%) also occur in the USA and Canada, 4 species (19%) also occur in Costa Rica, and 3 species and 1 subspecies (19%) are known from Mexico only. The most abundant species of the genus in Mexico is E. tarsalis.

Key words: fauna, key, Mexico, new species, taxonomy.

 

Resumen

Se registran 21 especies y subespecies de Exetastes Grav. para México. Se describen E. arteagus sp. nov., E. gauldi sp. nov. y E. lascivus sp. nov. Exetastes pasculus Gauld et Ugalde es registrada para México por primera vez. Se aportan datos nuevos sobre la distribución de Exetastes en México y una clave para identificar las especies. La fauna mexicana es más cercana a la neártica que a la de Costa Rica: 13 de las especies y subespecies mexicanas (62% del total) también se encuentran en Estados Unidos y Canadá, 4 especies (19%) ocurren en Costa Rica, y 3 especies y 1 subespecie (19%) se conocen solamente de México. Exetastes tarsalis es la especie más abundante del género en México.

Palabras clave: fauna, clave, Mexico, especies nuevas, taxonomía.

 

Introduction

Exetastes Grav. is a very large, almost worldwide genus (not recorded from Australia) with 50 species in the USA and Canada (Townes and Townes, 1978), and 18 species in Costa Rica (Gauld et al., 2002). Sixteen species were mentioned from Mexico by Ruiz et al. (2002), 14 of them were described by Cresson (1865, 1872, 1874) and Cushman (1937). The genus includes mostly moderate to large sized species, with fore wing length 5.2–13.5 mm. It is very distinctive genus which may easily be distinguished from other genera of Banchinae by the combination of the nervellus intercepted very high, and the large subrhombic areolet. All the species possess long and strong hind legs with enlarged coxae, and a robust, often short and decurved ovipositor. Some Mexican species possess a conspicuous bright white and black body color pattern. The genus is rather abundant in the Mexican ichneumonid fauna, and is often collected in various biotopes from lowlands to mountain regions, most commonly in open spaces. Some species are found on flowers. The majority of host records are from larvae of Noctuidae (Townes and Townes, 1978; Gauld et al., 2002). Host larva is destroyed in its pupal chamber, usually in soil. The parasitoid cocoon is elongate eliptical, hard, and black (Townes and Townes, 1978; Gauld et al., 2002).

The aim of the present work is to review the Mexican fauna of Exetastes, to estimate its relations to the Nearctic and Costa Rican faunas, and to provide a key to the species.

 

Materials and methods

Collections of the Universidad Autónoma de Tamaulipas in Ciudad Victoria and Universidad Autónoma de Nuevo León in Monterrey were studied. From this material, 3 new species are described, and new geographic records in Mexico are provided. This work is based on the monographs by Townes and Townes (1978) and Gauld et al. (2002). Classification follows the catalog TaxaPad (Yu et al., 2005). Morphological terminology of the body structures and wing venation predominantly follows Gauld et al. (2002). Photographs were taken with a Leica MZ16 stereomicroscope with an integrated Leica Digital Camera. Images were assembled with Helicon Focus software. Types of the new species are deposited at the Insect Museum of the Universidad Autónoma de Tamaulipas, Ciudad Victoria, Mexico (UAT) and Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León, Monterrey, Mexico (UANL).

Exetastes arteagus Khalaim et Ruiz–Cancino, sp. nov. (Figs. 1–3, 9–11)

Female holotype. Fore wing length 7.6 mm. Head (Figs. 1, 2, 10). Clypeus, in profile, distinctly and rather evenly convex, but less than in E. quarus (Gauld et al., 2002: Fig. 315), with lower margin blunt and slightly concave, mostly finely punctate and finely granulate, matt. Mandible weakly tapered, finely punctate basally, with upper tooth distinctly longer than the lower tooth, both teeth smooth and shining. Malar space about 0.80 times as long as basal width of mandible. Face and frons finely granulate, matt, finely and sometimes indistinctly punctate. Face with weak median convexity, and with small and rather sharp elongate projection dorsally. Frons almost flat. Vertex and genae without distinct punctures, almost smooth, matt. Head, in dorsal view, strongly and rather straightly narrowed behind eyes (Fig. 1); gena very short, 0.38 times as long as eye width (Fig. 1). Posterior ocellus separated from eye by 1.60 times its own maximum diameter. Lower end of occipital carina joining hypostomal carina above base of mandible. Antenna obviously longer than fore wing; flagellum apically strongly tapered, with 44 flagellomeres; middle and subapical flagellomeres slightly elongate. Mesosoma (Figs. 3, 9). Pronotum anteriorly irregularly–rugulose, latero–posteriorly finely granulate and finely and densely punctate. Epomia and notaulus absent. Mesoscutum densely and finely punctate, matt. Scutellum, in profile, distinctly roundly convex. Mesopleuron punctate, mostly matt, speculum smooth. Subtegular prominence moderately strong, rounded. Mesosternum densely punctate, matt. Hind rim of metanotum without a sublateral projection. Metapleuron finely and densely punctate, almost smooth between punctures. Propodeum, in profile, weakly convex, without carinae, with transverse wrinkling, with strongly elongate spiracle. Pleural carina developed, anteriorly weak and posteriorly stronger. Submetapleural carina anteriorly weakly raised. Legs with tarsal claws basally finely pectinate. Fore tibia unspecialized. Fore wing with cu–a postfurcal, distad of Rs&M by 0.33 its length. Areolet rather large, pointed above. Vein 2m–cu with 1 long bulla in its anterior part. Metasoma (Fig. 11). Mostly alutaceous anteriorly to polished posteriorly. First tergite 2.30 times as long as posteriorly wide; spiracle near basal 0.43. Ovipositor short, weakly decurved, with distinct dorsal subapical notch; sheath 0.33 times as long as hind tibia. Color. Head black; palpi strongly darkened; mandible (except teeth), clypeus (except small dark area in its lower part), face (except areas around clypeal fovea, and median vertical mark) and eye orbits (in holotype black area reaching margin of eye dorsally) white. Antenna with scape entirely black (in holotype) or with small whitish spot ventrally (in paratype); flagellum with white band on flagellomeres 10–16 (10–17 in paratype). Pronotum black with anterior margin white. Mesoscutum black with discrete anterolateral and central white marks. Scutellum black with wide V–shaped mark anteriorly. Postscutellum white. Tegula white. Mesopleuron reddish to black with white marks as in Fig. 3. Upper division of metapleuron mostly white, margined with red and black. Lower division of metapleuron mostly red, anteriorly and posteriorly usually blackish, posteriorly with wide white band. Propodeum black, anteriorly in front of spiracles white–marked, and with large posterolateral white marks. Pterostigma brown, basally whitish. Legs reddish; fore coxa dorsally black, white in front; middle and hind coxae dorsally with longitudinal black stripes, laterally usually whitish; hind femur basally and apically narrowly blackish; hind tibia fuscous in its apical 0.16; fore and mid tibiae dorsally slightly infuscate; fore and mid tarsi infuscate; hind basitarsus white with basal 0.3 black, tarsomere 2 entirely white, and tarsomeres 3–5 entirely black. Metasoma with first tergite black, anteriorly and posteriorly margined with white; second and following tergites anteriorly black and posteriorly white. Male unknown.

Morphological variation. The paratype is very similar to holotype, and differs predominantly in minor details of color pattern (differences mentioned in the description).

Comparison. It belongs to the mexicanus species group (Gauld et al., 2002) by having a short, slightly compressed and decurved ovipositor, and a metasomal tergites with transverse white and black bands. In the mexicanus species group it resembles the Costa Rican E. quarus as both have a black gena, but differs from this species by having the clypeus in profile not nasute, moderately and rather evenly convex, and hind femur and tibia mostly red. The new species also differs from E. tarsalis and E. vittatipes by having the gena black, and by the pattern of coloration of hind leg.

Etymology. It refers to the type locality.

Material examined. Holotype female (UAT): Mexico, Coahuila, W Arteaga, Rancho de los Pinos, 2 000 m, Malaise trap, 8–11.VII.2000, S. Hernández A., C. A. Covarrubias D. colls. Paratype: 1 female (UAT), same data as in holotype.

Distribution. Mexico (Coahuila).

Exetastes bifenestratus Cushman, 1937 (Figs. 17, 18)

Material examined. Mexico, Nuevo León: 5 females, 2 males, Pesquería, Malaise trap, 14–21.XI.1983, M. R. Cantú coll. 1 female, Santiago, Cola de Caballo, 1.IV.1981, E. Ruiz C. coll. Tamaulipas: 1 female, Cd. Victoria, park, 30.IX.1990, E. Ruiz C. coll. 1 female, 2 males, 15 km S Miquihuana, 3.X.1998, D. R. Kasparyan coll. 1 male, 45 km NE Cd. Victoria, Nuevo Padilla, 6.X.1988, E. Ruiz C. coll. 1 male, Mpio. Padilla, 8.V.2008, A. I. Khalaim coll.

Distribution. Mexico (Durango, Baja California, Tlaxcala, Tamaulipas, Coahuila, Jalisco, Nuevo León, San Luis Potosí, and Zacatecas), southern and eastern USA, and Cuba.

Biology. Reared from Agrotis sp. (Noctuidae) on Brassica oleracea (Brassicaceae), and cutworm pupa in Texas, USA (Townes and Townes, 1978).

 

Exetastes bioculatus Cresson, 1872 (Figs. 19, 20)

Material examined. Mexico, Nuevo León: 1 male, Santiago, 2.X.1987, H. Sosa coll. Zacatecas: 1 female, Villa García, 18.IV.1987, E. Ruiz C. coll.

Distribution. Northern Mexico (Nuevo León and Zacatecas) and USA.

 

Exetastes buccatus Cushman, 1937

Distribution. Northwest Mexico (Baja California) and USA (California).

 

Exetastes callipterus Cushman, 1937

Exetastes callipterus callipterus s. str.

Distribution. Northern Mexico (Chihuahua) and USA (southern Arizona and New Mexico).

 

Exetastes callipterus torquatus Townes, 1978 (Fig. 21)

Material examined. Mexico, Tamaulipas: 2 females, Ciudad Camargo, 26°18.33' N, 98°49.428' W, A. I. Khalaim, E. Ruiz C. colls. 1 female, Ciudad Miguel Alemán, 26°23.941' N, 99°01.675' W, 9.XII.2008, A. I. Khalaim coll. Oaxaca: 1 female, Ejutla de Crespo, 17.X.1948. 1 female, 4 males, 28°12'08.3" N, 107°20'18.2" W, 13.VIII.1999. Chihuahua: 1 male, Km 23 Carr. La Junta–Creel del Entronque a Basaseachic, 13.VIII.1999, J. A. Sanchez G. coll. 1 male, 20°47'56.6" N, 106°27'10.0" W, 12.VIII.1999.

Distribution. Northern and central Mexico (Tamaulipas, Chihuahua, Oaxaca, Morelos, Mexico D.F., Michoacán, and Nuevo León), above 1 750 m.

 

Exetastes carinatifrons Cushman, 1937

Distribution. Mexico (Durango and Nuevo León) and southern USA (Arizona, New Mexico, and Texas).

 

Exetastes fascipennis Cresson, 1865

Distribution. Mexico (Nuevo León, Zacatecas and Baja California), USA, and ?Canada.

Exetastes fornicator (Fabricius, 1781)

Exetastes fornicator flavipennis Cresson, 1865

Distribution. Mexico (Mexico D.F., Morelos, Coahuila, Chiapas, and Zacatecas), USA, and ?Canada.

 

Exetastes gauldi Khalaim et Ruiz–Cancino, sp. nov. (Figs. 4, 12, 13)

Female holotype. Fore wing length 10.4 mm. Head (Fig. 4). Clypeus, in profile, rather strongly convex in basal 0.67, subapically slightly concave, with lower margin blunt and slightly concave, with rare punctures medially in basal half, finely granulate, matt. Mandible weakly tapered, finely punctate, with upper tooth distinctly longer than the lower tooth, both teeth smooth and shining. Malar space 0.80 times as long as basal width of mandible. Face, frons, vertex and genae finely granulate, matt, finely and sometimes indistinctly punctate. Face with weak median convexity, and with small but rather sharp elongate projection dorsally. Frons almost flat. Head, in dorsal view, strongly narrowed behind eyes (Fig. 4); gena very short, 0.42 times as long as eye width (Fig. 4). Posterior ocellus separated from eye by 1.44 times its own maximum diameter. Lower end of occipital carina joining hypostomal carina above base of mandible. Antenna longer than fore wing; flagellum apically strongly tapered, with 56–58 flagellomeres; subapical flagellomeres subquadrate. Mesosoma (Fig. 13). Entirely granulate, matt, mostly finely and densely punctate, sometimes punctures indistinct; propodeum mostly coarsely wrinkled. Epomia and notaulus absent. Scutellum, in profile, strongly convex, almost pyramidal. Subtegular prominence rather high and sharp. Hind rim of metanotum without a sublateral projection. Propodeum, in profile, weakly convex, with median longitudinal carinae medially distinct, with elongate spiracle, impressed posteriorly next to hind coxae. Pleural carina complete, stronger anteriorly. Submetapleural carina anteriorly weakly raised. Legs with tarsal claws at extreme base finely pectinate. Fore tibia unspecialized. Fore wing with cu–a slightly postfurcal. Areolet rather large, pointed above. Vein 2m–cu strongly sinuate, with 1 long bulla in its anterior part. Metasoma. First tergite entirely and tergites 2–3 in basal 0.4–0.6 coriaceous, the rest metasoma more or less smooth, matt. First tergite 2.40 times as long as posteriorly wide, with spiracle near its basal 0.41. Ovipositor short, about as long as apical depth of metasoma, weakly decurved, with distinct dorsal subapical notch; sheath 0.26 times as long as hind tibia. Color. Head yellow; palpi mostly fuscous, labial segments 1, 4, 5, and segment 2 basally yellowish; mandible with teeth blackish; face in upper part medially with small brownish mark. Frons medially, interocellar area and its surroundings, vertex (except for eye orbits) and most of occiput black. Antenna black with scape ventrally broadly yellow; flagellum with yellowish band on flagellomeres 8–16. Propleuron yellow. Pronotum black with a rather large discrete spot towards upper posterior corner and anterior margin white. Mesoscutum black with anterolateral and central yellowish marks. Scutellum black, anteriorly with wide V–shaped mark. Postscutellum anteriorly white, posteriorly black. Tegula black. Mesopleuron yellow, with prepectus black in upper part, narrowly black below subtegular prominence and in upper part along mesopleural suture, with black marks in mesopleural fovea, with large reddish brown area centrally. Mesosternum mostly reddish brown. Upper division of metapleuron yellow. Lower division of metapleuron dorso–anteriorly blackish, posteriorly yellowish, and more or less reddish brown in interspace. Propodeum black, anteriorly in front of spiracle white–marked, and subposteriorly with transverse yellowish band. Wings and pterostigma yellowish brown. Fore and mid legs mostly reddish brown, coxae yellowish with black marks basally and on outer surface, trochanters dorsally blackish, tarsomeres 1–2 yellowish (tarsomere 2 dorsally blackish), tarsomeres 3–5 black. Hind leg mostly reddish brown, with coxa dorsally narrowly blackish, and in paratype also with dorsal longitudinal blackish stripe, tibia subbasally paler, tarsomeres 1–3 yellowish, tarsomeres 4–5 black. Metasoma reddish brown, first tergite with broad transverse medial blackish band, tergites 2–3 with transverse medial blackish band narrow and vestigial. Ovipositor sheath blackish, apically paler. Male unknown.

Morphological variation. The paratype is very similar to holotype, and differs predominantly in minor details of color pattern (differences mentioned in the description).

Comparison. The new species belongs to the mexicanus species group by having a short, slightly decurved ovipositor (Fig. 12), but it has a metasoma predominantly reddish brown, without transverse black and white markings (Fig. 12) in contrast to the other 5 Mexican species of this species group (Figs. 9, 28). It differs from other species of the genus in North and Central America by the combination of very short gena (Fig. 4), tricolored (yellow, reddish brown and black) mesopleuron (Fig. 13), yellowish brown wings, color pattern of hind leg (femur and tibia evenly reddish brown, not infuscate, tarsomeres 1–3 whitish, 4–5 black), brown metasoma without whitish bands, and a short, decurved ovipositor (Fig. 12).

Etymology. Named in memory of the well–known expert in Ichneumonidae, Dr. Ian Gauld (U.K.), who has made a great contribution to study of Ichneumonidae of Costa Rica.

Material examined. Holotype female (UAT): Mexico, Chiapas, Jactenango, reserva El Triunfo, Malaise trap, CIB 97–232, 19–22.VII.1999, A. González H. coll. Paratype female (UANL), Mexico, Yucatán, Río Lagartos, Malaise trap, 9.VII.1996, P.R.R. & C.N.C. coll.

Distribution. Mexico (Chiapas and Yucatán).

 

Exetastes igneipennis Cushman, 1937 (Fig. 5)

Material examined. Mexico, Tamaulipas: 1 male, 15 km S Miquihuana, 3.X.1998, D. R. Kasparyan coll. Oaxaca: 1 female, Neochitlan, 16.IX.19?8. Guanajuato: 1 female, Yuriria, 17.V.1986, J. C. Méndez coll.

Distribution. Mexico (Oaxaca, Mexico D.F., Durango, Puebla, Chihuahua, Nuevo León, Michoacán, Zacatecas, Guanajuato, Jalisco, and Tamaulipas) and USA.

 

Exetastes lascivus Khalaim et Ruiz–Cancino, sp. nov. (Figs. 6, 7, 14–16)

Female holotype. Fore wing length 7.0 mm. Head (Fig. 6). Clypeus, in profile, distinctly convex and very densely punctate in its upper third, flattened and almost smooth in its lower part, with lower margin distinctly truncate. Mandible strong, weakly tapered, densely punctate in its basal half, smooth and shining in its apical part, with lower tooth distinctly wider and longer than the upper tooth, both teeth smooth and shining. Malar space 0.60 times as long as basal width of mandible. Face and frons entirely very densely punctate, matt. Face with weak median convexity. Vertex and genae finely punctate, smooth between punctures. Head, in dorsal view, roundly narrowed behind eyes (Fig. 6); gena short, 0.58 times as long as eye width (Fig. 6). Posterior ocellus separated from eye by 1.90 times its own maximum diameter. Juncture of occipital and hypostomal carinae separated from base of mandible by about half the basal width of the latter. Flagellum of antenna tapered apically, with 48 flagellomeres; all flagellomers elongate. Mesosoma (Fig. 15). Entirely more or less coarsely and rather densely punctate, mostly smooth between punctures, punctures separated by a distance distinctly shorter than diameter of puncture. Epomia and notaulus absent. Scutellum, in profile, weakly convex. Subtegular prominence moderately strong, rounded. Propodeum, in profile, weakly convex, with median longitudinal furrow, with apical transverse carina well–developed medially, enclosing a small apical area, with oval spiracle about twice as long as wide, its surface uneven but without obvious wrinkling. Pleural carina developed only posteriorly. Submetapleural carina anteriorly broadened into a rounded lobe. Legs with tarsal claws weakly curved, basally very finely pectinate. Fore wing with cu–a slightly postfurcal. Ramulus absent. Areolet oblique, pointed above, not stalked. Vein 2m–cu weakly curved in its anterior half, with 1 long bulla. Metasoma (Figs. 7, 16). Tergites polished. First tergite 1.9 times as long as posteriorly wide, basolaterally distinctly and rather densely punctate, and posterolaterally sparsely punctate, with spiracle near its basal 0.4. Tergites 2 and 3 laterally with short sparse hairs, dorsally hairless. Ovipositor short, almost straight, about as long as apical depth of metasoma (Fig. 7). Color. Head and mesosoma mostly black. Palpi, most of metapleuron (margined with black anteriorly, ventrally and dorsally), spot above propodeal spiracle, and legs (coxae, especially front coxa, basally more or less blackish) reddish brown. Basal half of mandible, transverse median stripe on clypeus, front margin and distal corner of pronotum, anterolateral subtriangular spot of mesoscutum, scutellum dorsally, postscutellum, tegula, subtegular prominence, upper mesepimeron and base of wings yellow. Pterostigma and metasoma, including first tergite, brown. Male unknown.

Comparison. The new species belongs to the bioculatus species group (Townes and Townes, 1978) by having the upper tooth of mandible distinctly shorter than lower tooth, predominantly black head and mesosoma (sometimes with white or yellowish marks), short ovipositor, and relatively small size. It differs from the both species of this group, E. bioculatus and E. pictus, by the flagellum black, without a whitish band, and legs almost entirely and evenly reddish brown (coxae basally blackish). Also it differs from E. bioculatus by the propodeum coarsely punctate, without obvious wrinkling, and from E. pictus by the propodeum and metapleuron black and reddish brown.

Etymology. From the Latin lascivus (cheerful, playful).

Material examined. Holotype female (UAT), Mexico, Tamaulipas, 15 km S Miquihuana, 3.X.1998, D. R. Kasparyan coll.

Distribution. Mexico (Tamaulipas).

 

Exetastes mexicanus Cresson, 1874

Distribution. Mexico (Veracruz) and Costa Rica.

 

Exetastes obscurus Cresson, 1865

Biology. Reared from Agrotis gladiaria Morrison in Kansas, and Agrotis vetusta Walker (Noctuidae) in Oregon (Townes and Townes, 1978).

Distribution. Mexico (Baja California), USA, and Canada.

 

Exetastes pasculus Gauld et Ugalde, 2002

Material examined. Mexico, Tamaulipas: 1 female, Cd. Victoria, El Madroño, 23.XII.1987, H. Ruiz C. coll. 1 female, Gómez Farías, Alta Cimas, 900 m, Malaise trap, 4–11.XI.2000, D. R. Kasparyan coll.

Variability. Both studied specimens from Mexico well corresponds with Gauld's original description except hind tarsus with tarsomeres 1–4 yellow (tarsomere 1 narrowly blackish or brownish basally) and the distal tarsomere black. The Costa Rican specimen, according to original description, possesses tarsomeres 1–3 yellow, and the distal 2 tarsomeres black. Moreover the specimen from Gómez Farías has a pronotum with a very small pale spot which is hardly discernible. See also variability for E. tarsalis.

Distribution. Mexico (Tamaulipas) and Costa Rica. First record from Mexico.

 

Exetastes pictus Cushman, 1937 (Figs. 22, 23)

Material examined. Mexico, Tamaulipas: 5 females, 1 male, Cd. Victoria, Cañón del Novillo, Malaise trap, 2.VII–12.XI.2003, B. A. Pérez Urbina coll. 1 male, 14 km W Jaumave, La Florida, Malaise trap, 13–20.V.2005, D. R. Kasparyan, O. Pinson D. colls.

Distribution. Mexico (Tamaulipas) and USA (Arizona and Texas).

 

Exetastes rhampha Townes, 1978 (Figs. 8, 24–27)

Material examined. Mexico, Coahuila: 3 females, 5 males, W Arteaga, Rancho de los Pinos, 2 000–2 300 m, Malaise trap, 8–11.VII.2000, S. Hernández A., C. A. Covarrubias D., D. R. Kasparyan colls. Jalisco: 1 female, "T89046".

Distribution. Mexico (Coahuila, Michoacán, Jalisco, and Mexico) and USA (Arizona).

 

Exetastes scutellaris Cresson, 1865

Distribution. Mexico (Baja California), USA, and Canada.

 

Exetastes septum Cushman, 1937

Biology. Reared from Catabena lineolata Walker (Noctuidae) and Cydia pomonella L. (Tortricidae) in California (Townes and Townes, 1978).

Distribution. Mexico (Nuevo León and Baja California) and USA (California and Oregon).

 

Exetastes tarsalis Cresson, 1874 (Figs. 28–30)

Material examined. Mexico, Tamaulipas: 2 females, Llera de Canales, bushes, Malaise trap, 18–25.XI.2000, D.R. Kasparyan coll. 2 females, same locality, Río Guayalejo, 27.III.2000, D.R. Kasparyan coll. 9 females, 4 males, NW Cd. Victoria, Los Troncones (park), 20.XII.2007, 23.II.2008, 26–31.XII.2008, A. I. Khalaim coll. 1 male, same locality and collector, yellow pan traps, 13–22.IV.2008. Gómez Farías: 57 females, 78 males, Alta Cimas (900 m), Los Cedros, Malaise trap, XII.1998–IX.2000, S. Hernández A., C. A. Covarrubias D., D. R. Kasparyan colls. Veracruz: 1 male, Estación Biológica Los Tuxtlas, 480 m, 21.III.1986, E. Ramírez coll.

Remarks. Total of 154 specimens of E. tarsalis from Mexico have been studied. Eleven of 70 females (16%) and 53 of 84 males (63%) have a discrete pale spot on pronotum laterally. This spot varies from moderately large to very small and inconspicuous, or sometimes this spot present only on one side of pronotum and completely absent on the opposite side. Other characters correspond well with description of E. tarsalis in Gauld et al. (2002), and we are sure that these specimens belong to this species. Thus this character (absence or presence of a separate pale spot on pronotum) does not work well on the Mexican material of E. tarsalis, and when using Gauld's key (Gauld et al., 2002) to Costa Rican species some Mexican specimens with a pale spot on pronotum run into E. pasculus.

Distribution. Mexico (Tamaulipas and Veracruz) and Costa Rica.

 

Exetastes vittatipes Cresson, 1874

Material examined. Mexico, Tamaulipas: 1 female, Gómez Farías, Alta Cimas, Malaise trap, 1–8.V.1999, S. Hernández A. coll.

Distribution. Mexico (Tamaulipas and Veracruz) and Costa Rica.

 

Discussion

Twenty one species and subspecies of Exetastes are recorded from Mexico, 13 of them (62%) also occur in the USA and Canada (Townes and Townes, 1978), 4 (19%) in Costa Rica, and 3 species and 1 subspecies (19%) are known from Mexico only. It appears that the Mexican fauna of Exetastes is closer to the fauna of the USA and Canada than to the Costa Rican one, but proportions of the Mexican species in America north of Mexico and Costa Rica are subequal: 13 of 50 species of America north of Mexico (26%), and 4 of 18 Costa Rican species (22%) are known also from Mexico.

All 4 Costa Rican species found in Mexico (E. mexicanus, E. pasculus, E. tarsalis and E. vittatipes) belong to the mexicanus species group (Gauld et al., 2002). The Mexican species of this group possess a short, slightly compressed and decurved ovipositor (Fig. 30), and metasomal tergites with a transverse black and white markings (Figs. 9, 28). One new species, E. arteagus sp. nov., clearly belongs to this group by having a short decurved ovipositor and metasoma with black and white markings (Figs. 9, 11). These 5 species are separated in the first couplet of the key by the charateristic transverse black and white marks on tergites, due to the fact that none of the Nearctic species found in Mexico have this type of coloration of metasoma. Another new species, E. gauldi sp. nov., is also included into the mexicanus species group by having an ovipositor that is short and slightly decurved (Fig. 12), but in the key it runs to the "Nearctic" complex of species because it has a metasoma predominantly reddish brown. These 6 species form a "tropical" complex of species in the Mexican fauna of Exetastes.

Thirteen species of the Mexican fauna occur north of Mexico in the USA and Canada. These species, and also E. lascivus sp. nov. belonging to the Nearctic bioculatus species group (Townes and Townes, 1978), and form a "Nearctic" complex of species, which is characterized by metasoma more or less unicoloured, without transverse white markings (only 1 species on the "tropical" complex, E. gauldi sp. nov., has similar uniformly colored metasoma), and ovipositor that is short to long, decurved, straight or curved upward (all species of the "tropical" complex have a short, slightly decurved ovipositor).

The most abundant species of the genus in Mexico is E. tarsalis, from the "tropical" complex of species, which is most regularly collected in Mexico in forests up to 900 m in altitude. The Mexican population of this species is characterized by the pronotum either with or without a separate central pale spot (this spot is absent in Costa Rican material), thus this character cannot be used for separation of this species from E. pasculus.

 

Acknowledgments

We are thankful to D. R. Kasparyan (Zoological Institute of the Russian Academy of Sciences, St. Petersburg) for his help with the preparation of this paper. This work was supported by the Russian Foundation for Basic Research (no. 10–04–00265), the Presidium of the Russian Academy of Sciences Program "Origin and evolution of Biosphere, Subprogram II", the CONACyT Project "Ichneumonidae y Aphelinidae (Hymenoptera) en bosques y matorrales de Tamaulipas, México", the PROMEP Project "Avances en el conocimiento de la entomofauna de México", and the UAT.

 

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