Труды Русского энтомологического общества. С.-Петербург, 2014. Т. 85(1): 98–102. Proceedings of the Russian Entomological Society. St Petersburg, 2014. Vol. 85(1): 98–102.
Mexican species of the subgenus Dicolus Förster, genus Megastylus Schiødte (Hymenoptera: Ichneumonidae: Orthocentrinae), with descriptions of a new species A.E. Humala Мексиканские виды подрода Dicolus Förster рода Megastylus Schiødte (Hymenoptera: Ichneumonidae: Orthocentrinae) с описанием нового вида А.Э. Хумала Forest Research Institute, Karelian Research Centre, Russian Academy of Sciences, 11 Pushkinskaya Street, 185910 Petrozavodsk, Russia. E-mail:
[email protected]
Abstract. A new species of the genus Megastylus Schiødte, M. (Dicolus) kasparyani sp. n., is described from tropical Mexico. New data on distribution of the Holarctic species M. (D.) pectoralis Förster in Mexico is provided. Key words. Orthocentrinae, Megastylus, new species, Mexico, North America, Neotropics. Резюме. Описан новый вид наездников-ортоцентрин Megastylus (Dicolus) kasparyani sp. n. из тропиков Мексики. Приведены новые данные по распространению голарктического вида M. (D.) pectoralis Förster. Ключевые слова. Orthocentrinae, Megastylus, новый вид, Мексика, Северная Америка, Неотропика.
Introduction Megastylus Schiødte, 1838 is relatively large orthocentrine genus occurring worldwide and comprising 34 species (Yu et al., 2012). The genus is divided into two subgenera: Megastylus s. str. containing 27 species and Dicolus Förster, 1869 with seven species. However, many species of the genus are still not described, and even the European fauna has not been studied satisfactory. The Nearctic fauna of the genus was revised by C. Dasch, who reported there 14 species of Megastylus (Dasch, 1992), while the Neotropical fauna remains almost unknown. Megastylus species were not included in the Catalogue of Neotropical Ichneumonidae (Townes, Townes, 1966), though the genus is among the species-rich in Neotropics (Townes, 1971; Gauld, 1991; Veijalainen et al., 2012). Members of this genus are known as koinobiont parasitoids of nematocerous Diptera (Sciaroidea: Keroplatidae) larvae. In the course of long-term research on the Mexican fauna of ichneumonid wasps, conducted at the Autonomous University of Tamaulipas (Cd. Victoria, Mexico), only one species of the subgenus Dicolus, M. (D.) pectoralis Förster, 1871, has been reported from this country (Humala et al., 2011). One more new Mexican species of this subgenus is described in this paper. A review of Mexican species of the subgenus Megastylus, with descriptions of several new species, will be published in my forthcoming paper. 98
Material and methods The specimens examined in this study are deposited in or were borrowed from the following collections: Universidad Autónoma de Tamaulipas, Cd. Victoria, Tamaulipas, Mexico (UAT) and Universidad Nacional Autónoma de México, D.F., Mexico (UNAM). The morphological terminology mostly follows Gauld (1991). Observations were made using a MBS-10 stereomicroscope. Photographs were taken with a DFC 290 digital camera attached to a Leica MZ9.5 stereomicroscope; images were combined using Helicon Focus Pro v. 5.3 software.
Taxonomic part Genus Megastylus Schiødte, 1838 Subgenus Dicolus Förster, 1869 Type species: Dicolus insectator Förster, 1871. Megastylus species have a unique scape structure amongst the Orthocentrinae and Ichneumonidae: it is large and inflated, the hind edge of its apical truncation membranous and in dry specimens infolded. All species of the subgenus Dicolus can be distinguished from other Megastylus species by the anterior transverse groove of propodeum situated at the anterior 0.25–0.3 of the propodeum and well separated from the postscutellum medially, together with an elongate first flagellomere. Megastylus (Dicolus) kasparyani sp. n. (Figs 1–7) Differential diagnosis. This new species differs from other known New World Dicolus species by the combination of the following characters: flagellum with 47 flagellomeres; first flagellomere long, 9.2 times as long as wide; vein 2m-cu with two bullae; propodeum with two transverse carinae; base of fore coxa with transverse carina. From the Holarctic M. impressor Schiødte, 1838 it may easily be separated by the wider face and subparallel inner eye orbits (convergent ventrally in M. impressor), long malar space, more rough sculpture of head and mesosoma, not so conspicuous pubescence on flagellum, tawny face and pale markings along frontal orbits. Description. F e m a l e . Body length 5.4 mm, fore wing 4.9 mm (Fig. 1). Head width 0.95 times its height; head matt, sparsely punctate. Face at level of antennal sockets 0.55 times as wide as head width, its inner orbits subparallel (Fig. 2). Margins of antennal sockets raised to form round lamellae. Scape ovoid, considerably inflated and obliquely truncate at about 70° from transverse; antenna long, with 47 flagellomeres, first flagellomere 9.2 times as long as wide, second flagellomere 3.8 times as long as wide; all flagellomeres longer than wide and densely covered with long erect setae exceeding diameter of segments. Frons dull, nearly impunctate; face coriaceous, scarcely punctate. Clypeus narrow, strongly convex, about 1.6 times as wide as high, its apical margin slightly convex; clypeal foveae large and open. Malar space very long, 2.5 times as long as basal width of mandible, 0.35 times as long as face width, with distinct impressed subocular sulcus and more roughly sculptured coriaceous strip between eye and base of mandible (Fig. 6). Mandible slender, strongly tapered and turned inwards, lower tooth small, much shorter than upper tooth; maxillary palps long. Ocelli of moderate size, ocular-ocellar line about 1.2 times as long as maximum diameter of lateral ocellus, postocellar line 0.8 times as long as maximum diameter of lateral ocellus (Fig. 3). Occipital carina complete. Mesosoma coriaceous, its length 1.6 times height; epomia lacking. Epicnemial carina well developed, almost reaching hind margin of pronotum at its mid-height (Fig. 5). Mesoscutum convex, with sparse small punctures bearing long setae; notaulus shallow, developed to centre of mesoscutum. Scutellum with lateral longitudinal carinae reaching its posterior end. Sternaulus weak and indistinct. Propodeum covered with rather long setae, both transverse carinae complete, lateral longitudinal carinae developed only anteriorly, lateromedian longitudinal carinae lacking (Fig. 7). Propodeal spiracle circular, separated from pleural carina by one diameter of spiracle. Fore wing with vein 2m-cu slightly postfurcal, vein 3rs-m entirely absent, 2m-cu with two bullae, nervellus intercepted in lower third, discoidella depigmented. Legs long and slender; base of fore coxa with distinct transverse carina (Fig. 6); hind coxa matt, hind femur 8.1 times as long as broad, 0.75 times as long as hind tibia; hind basitarsus 0.45 times as long as hind tibia; distal end of hind tibia with an internal fringe of long, fine, dense setae, spurs straight and very slender, tarsal claws slender and simple. First tergite of metasoma slender, slightly constricted behind spiracles, 4.1 times as long as posteriorly broad, matt, with sparse long setae laterally; glymma lacking; spiracles protruding, situated at anterior 0.45 of tergite; postpetiole some-
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what inflated in middle and narrowed to apex (Fig. 4); longitudinal carinae lacking; first sternite fused to tergite, 0.65 times as long as tergite length, in lateral view forming weakly rounded lobe in its anterior half; second tergite 1.6 times as long as posteriorly broad. Remaining tergites more finely sculptured, metasoma weakly compressed to apex. Metasomal tergites covered with long setae started from second tergite. Ovipositor short and slender, its sheath as long as hind femur broad. C o l o u r p a t t e r n . Head black; clypeus and face medially, except for fuscous wedge-shaped area between antennal sockets, yellowish brown, more dusky on facial margins and malar space. Scape brown, flagellum fuscous; mandibles
Figures 1–4. Megastylus kasparyani sp. n. (female): 1 – habitus, lateral view; 2 – head, anterior view; 3 – head, dorsal view; 4 – basal tergites of metasoma, dorsal view. Scale bars: 1 – 1.0 mm; 2–4 – 0.25 mm.
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except for reddish teeth, palps, tegulae and spots along frontal orbits pale yellow. Mesosoma fuscous, mesepimeron and pronotum excluding anterior part reddish brown; propleurum mostly brown; mesopleurum dark brown; metasoma fuscous, tergite 3 light brown anteriorly. Fore and mid legs light brown, with coxae and trochanters yellowish. Hind coxa light brown, infuscate dorsally; hind femur light brown, trochantellus and narrow anterior spot of hind femur somewhat infuscate; hind tibia and tarsus more fuscous. Wings hyaline, pterostigma and veins brown. M a l e . Unknown.
Figures 5–7. Megastylus kasparyani sp. n. (female): 5 – head, mesosoma and base of metasoma, lateral view; 6 – head latero-ventroanterior view; 7 – propodeum, latero-dorsoposterior view. Scale bars: 5 – 0.5 mm; 6, 7 – 0.25 mm.
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Etymology. The species is named in honor of my teacher and colleague Dr Dmitri R. Kasparyan in recognition of his valuable study of the Mexican Ichneumonidae fauna. Material examined. Holotype: female (UNAM), Mexico, Oaxaca, Santiago Comaltepec, 2427 m, N 17.58424º, W 96.49428º, humid oak pine forest, Malaise trap, 12–20.VI.2007 (H. Clebsch leg.).
Distribution. Mexico (Oaxaca). Megastylus (Dicolus) pectoralis Förster, 1871 The species is easily recognizable as the female hind tibia is inflated in the proximal two thirds and with strong subapical constriction, vein 2m-cu with a single bulla, the propodeum has only the posterior transverse carina, and the head and mesosoma are pale. Material examined. 1 female (UAT), Mexico, Tamaulipas, Gómez Farías, Los Cedros, Malaise trap, 16–26.XIII. 1998, leg. S. Hernández and C. Covarrubias.
Distribution. Holarctic: Canada, USA (Alaska, Oregon), Mexico (Tamaulipas), Europe, Western Siberia, Russian Far East. Remarks. It is southernmost known locality for this species.
Acknowledgements I am grateful to Andrey Khalaim (ZISP, UAT) for providing the valuable material for this study, and the Cuerpo Academico Entomologia Aplicada (UAT) for loans of the specimens under their care.
References D a s c h C . 1992. The Ichneumon-flies of America North of Mexico. Part 12. Subfamilies Microleptinae, Helictinae, Cylloceriinae and Oxytorinae (Hymenoptera: Ichneumonidae). Memoirs of the American Entomological Institute, 52: 1–470. G a u l d I . D . 1991. The Ichneumonidae of Costa Rica, 1. Introduction and keys to subfamilies, and keys to the species of the lower pimpliform subfamilies Rhyssinae, Poemeniinae, Acaenitinae and Cylloceriinae. Memoirs of the American Entomological Institute, 47: 1–589. H u m a l a A . E . , R u í z - C a n c i n o E . , C o r o n a d o - B l a n c o J . M . 2011. Orthocentrinae (Hymenoptera: Ichneumonidae) nuevos y poco conocidos de México. Memorias 21 y 22 Encuentro Nacional de Investigación Científica y Tecnológica del Golfo de México (May 2011, Tampico, Tamaulipas, México): 196–200. T o w n e s H . K . 1971. The genera of Ichneumonidae, part 4. Memoirs of the American Entomological Institute, 17: 1–372. T o w n e s H . K . , T o w n e s M . 1966. A catalogue and reclassification of the Neotropic Ichneumonidae. Memoirs of the American Entomological Institute, 8: 1–367. Veija la in en A., Wah lb er g N., Broad G. R., Er win T. L., Lon gin o J. T., Sääks jär vi I. E. 2012. Unprecedented ichneumonid parasitoid wasp diversity in tropical forests. Proceedings of the Royal Society of London, Series B – Biological Sciences, 279: 4694–4698. Y u D . S . K . , v a n A c h t e r b e r g C . , H o r s t m a n n K . 2012. Taxapad 2012, Ichneumonoidea 2011. Database on flash-drive. www.taxapad.com, Ottawa, Ontario, Canada.
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