A new species of Gryon Haliday (Hymenoptera: Platygastridae) from India

 

 

Abhilash Peter 1 & K. Rajmohana 2

 

 

1,2 Zoological Survey of India, Western Ghat Regional Centre (Recognised Research Centre of Calicut University), Kozhikode, Kerala 673006, India

1 abhilashpeter@gmail.com, 2 mohana.skumar@gmail.com (corresponding author)

 

 

doi: http://dx.doi.org/10.11609/JoTT.o3903.6711-4 | ZooBank: urn:lsid:zoobank.org:pub:1211B714-AF89-498B-94E7-801D59BBFD6C

 

Editor: Mohammad Hayat, Aligarh Muslim University, Aligarh, India. Date of publication: 26 December 2014 (online & print)

 

Manuscript details: Ms # o3903 | Received 02 January 2014 | Final received 09 December 2014 | Finally accepted 11 December 2014

 

Citation: Peter, A. & K. Rajmohana (2014). A new species of Gryon Haliday (Hymenoptera: Platygastridae) from India. Journal of Threatened Taxa 6(14): 6711–6714; http://dx.doi.org/10.11609/JoTT.o3903.6711-4

 

Copyright: © Peter & Rajmohana 2014. Creative Commons Attribution 4.0 International License. JoTT allows unrestricted use of this article in any medium, reproduction and distribution by providing adequate credit to the authors and the source of publication.

 

Funding: None.

 

Competing Interest: The authors declare no competing interests.

 

Acknowledgements: Authors are grateful to the Director, Zoological Survey of India (ZSI), Kolkata and the Officer- in-Charge, ZSI, Calicut, for encouragement and facilities provided. The authors are extremely thankful to L. Masner for confirming the placement of this species in Leptocorisae species group. We also thank the Platygastroidea Planetary Biodiversity Inventory project for literature support. 

 

 

 

Abbreviations: OOL - Ocellocular length; OD - Diameter of posterior ocellus; POL - Posterior ocellar length; LOL - Lateral ocellar length [distance between anterior and posterior ocellus]; PM - Postmarginal vein; STG - Stigmal vein; M - Marginal vein; A1–A12 - Antennal segments 1–12; T1–T5 - Tergites 1–5 of metasoma; HL - Head length; HW - Head width; L - Length; W - Width; ML - Mesosoma length; MW - Mesosoma width.

 

 

The genus Gryon (Hymenoptera: Platygastridae: Scelioninae) was erected by Haliday (1833), based on the type species Gryon misellum Haliday.  The genus is cosmopolitan and highly diverse.  A total of 57 species are known from the Oriental region (Johnson 1992; Ohio State University 2013), of which 17 species have been recorded from India (Mineo 1991; Mineo & Caleca 1994; Rajmohana 2011).  The species of this genus generally attack eggs of Hemiptera belonging to Coreidae, Pentatomidae, Scutelleridae, Lygaeidae, Reduviidae, Phymatidae (Rajmohana et al. 2011).

This genus can be easily distinguished from the rest of the scelionines by the presence of an unarmed metascutellum and propodeum, absence of skaphion, short and plump; and transverse terminal metasomal segment which is not wedge-shaped (Masner 1976; Rajmohana 2013).  In this paper a new species, Gryon ambericum sp. nov., is described and illustrated.

 

Material and Methods

This study is based on specimens collected from a paddy ecosystem as well as from the wild, by the authors.  The specimens were studied under a Leica M 205A stereomicroscope.  Images were taken with a digital camera Leica DFC 500 and processed using extended focus LAS montage software. The types are deposited at the Western Ghats Regional Centre, Zoological Survey of India, Kozhikode, Kerala (ZSI, WGRC).  Morphological terminology follows Masner (1980) and Miko et al. (2007).

 

 

Gryon ambericum sp. nov.

(Images 1–8)

urn:lsid:zoobank.org:act:EB03F38D-4A70-4300-9D17-300AE4588E5F

 

 

 

 

 

 

Material examined: Holotype. ZSI/WGRS/IR.INV.3008, female, 09.i.2009, 11039’651N & 76005’318E, Madakkimala, Kalpetta, Wayanad District, Kerala, India, coll. Rajmohana; Paratype: ZSI/WGRS/IR.INV.3055, female, 09.i.2009, 11039’651N & 76005’318E, Madakkimala, Kalpetta, Wayanad District, Kerala, India, coll. Rajmohana.

Additional material examined: ZSI/WGRS/IR.INV.3167, female, 10.xii.2013, 10024’920N & 76044’812E, Anakkalvayal, Parambikulam, Palakkad District, Kerala, India, coll. Abhilash Peter; ZSI/WGRS/IR.INV.3168, female, 12.xii.2013, 10025’400N & 76046’226E, Pillackalvayal, Parambikulam, Palakkad District, Kerala, India, coll. Abhilash Peter.

 

Description

Female.  Holotype.  Length, 0.97mm.  Head black; eyes and ocelli silvery.  Antenna brown with scape pale yellow basally and brown at distal fourth.  Mesosoma rusty or yellowish-brown (= amber) except mesoscutum laterally near tegula, brown; mesoscutum and mesoscutellum medially with irregular dark patches. Wings hyaline, veins yellowish-brown.  Legs, including coxae, yellow.  Metasoma rusty or yellowish-brown; posterior third of T2 and other tergites till tip of liver brown.

Head, in dorsal view (Image 2), roughly quadrate [HL: HW= 22: 28], slightly transverse; head subtriangular in lateral view; pubescence irregularly scattered on occiput and ocellar triangle, but arranged equidistant along a line near inner orbits, much sparse towards clypeal area and outer orbits near gena; frontal depression deep, with distinct transverse striae extending throughout on upper reaches, followed by concentric arched striations reaching upto inner eye margin and gradually merging with leathery sculpture; striations not margined by inverted U-shaped carina; vertex anterior to front ocellus transversely striate, but with leathery sculpture towards extreme sides near orbits; rest of head towards gena, occiput and ocellar triangle with distinct leathery reticulate sculpture; hairs absent in frontal depression; submedian carina not indicated; a short stumpy central keel present, hardly reaching one-fourth the level of eyes on frons; eyes large, without pilosity, inner margins sub parallel; inner orbital distance less than eye height, in front view (14:17); in lateral view eye height 3× as long as gena; clypeus arched, convex with lateral pointed corners; malar sulcus narrow and distinct; genal carina distinct, continuing posteriorly along occiput; ocellar triangle, wide; POL: LOL: OOL: OD= 10:5:2:2; lateral ocelli close to eye margins than to front ocellus, separated from margin by almost its own diameter.  Mandibles bidentate; Antenna slender, 12-segmented (Image 3); relative L: W-19:3; 6:2; 3:2; 3:2; 2:2; 3:2; 3:3; 3:4; 3:4; 3:4; 3:4; 5:3; radicle small, not reaching one-fourth length of scape.

Mesosma, in dorsal view, ML: MW = 36:25, not as wide as head (25:28); densely hairy, with setigerous pits and leathery sculpture (Image 6); mesoscutellum overlapping metascutellum, carinate and foveolate posteriorly; metascutellum smooth, overhanging median propodeum anteriorly, unarmed; metanotum foveolate laterally; propodeum with vague and short longitudinal striae; posterior propodeal carina distinct; lateral pronotal area reticulo- foveolate, but with a median smooth patch; netrion narrow and smooth with elongate striae bordering anteriorly; mesopleural carina distinct (Image 8); sternaulus prominent; speculum smooth; mesepimeral and metapleural epicoxal sulci distinct; acetabular patch distinct, finely hairy; lower mesepisternum foveolate; metapleural carina distinct; metapleuron near hind coxae sparsely hairy. Forewing exceptionally narrow (Image 7), L:W= 95:24; M and PM elongate; M 2.1× shorter than PM; PM 3× longer than STG; PM:STG:M = 19:6:9.

Metasoma, in dorsal view, L: W= 50:22, unusually elongate (2.27×), 1.38× longer than mesosoma and 1.16× shorter than head and mesososma combined, hairy towards sides; T1 anteriorly foveolate, followed by longitudinal striae and with a posterior smooth band as long as anterior striae (Image 5); T2 largest of all tergites, 2.6× longer than T1 and 3× longer than T3; T2 anteriorly with short costae, followed by large reticulate sculpture extending upto 0.8 of T2 length, bordered posteriorly by a smooth band, as long as its anterior costae; T2 sparsely hairy posteriorly; T3, T4, T5 anteriorly with same sculpture as that on dorsal mesoscutum and mesoscutellum, and with a posterior narrow smooth band; T4 onwards densely hairy; last metasomal segment with two pairs of unequal anal cerci on either side; relative length to width proportion of metasomal segments T1 to T3 being (8: 18); (21: 22); (7: 19).

Etymology: The species name ambericum based on the amber (= yellowish-brown) colour of the mesosoma and metasoma.

 

 

Discussion

The new species, Gryon ambericum sp. nov., belongs to the leptocorisae species-group of Gryon.  As defined by Mineo (1990), members of this group share the following characters: slender clava; incomplete occipital carina, almost surpassing the foramen magnum and without the horizontal branch; epomia strongly reduced; clypeus with anterolateral corners almost acute; M about as long as STG and an elongate PM (more than twice STG).

In the key to the Indian species given by Sharma (1982), G. ambericum runs out at couplet number 2, and as no recent keys are available to the Oriental species or Indian region, this new species is compared with the descriptions of all species of Gryon so far reported from India and the Oriental region.  The following unique characters serve as diagnostic characters of this species: a unique dorsally quadrate (Image 2), laterally subtriangular black coloured head and a quite contrasting amber coloured mesosoma; head width only 1.2x head length; frontal depression deep, not margined by a carina (Image 4); eyes without pilosity; mandibles bidentate; metasoma unusually elongate, more than 2x as long as wide, unlike the short and plumpy stature commonly met with in the genus; and T2 largest of all tergites, 2.6× longer than T1 and 3× longer than T3.

All Gryon species known so far from India have a much wider head, with dorsal width to length ratio usually equal to or greater than two and metasoma length to width ratio has never exceeded 1.5× and hence cannot be confused with G. ambericum sp. nov.

Three Vietnamese species of Gryon (Lê 2000) show a slight resemblance to G. ambericum sp. nov. as regards the shape of head and metasoma. However, G. ambericum can be distinguished from G. longus Kozlov et Lê, G. varius Kozlov et Lê and G. narus Kozlov et Lê by the following characters: (i) In G. ambericum sp. nov., head width is 1.3× its length and metasoma length 2.3× its width (in G. longus head width is 1.5× its length, metasoma length 1.5× its width), and (ii) In G. ambericum sp. nov., scape length is 6.3× length of radicle, forewing length is 3.95× its width and PM 3.1× STG (in G. varius scape length is 5× that of radicle, forewing length 2.5× its width, PM 2.5× STG whereas in G. narus scape length is only 4.2× that of radicle; forewing length is only 2.8× its width).

 

 

References

 

Haliday, A.H. (1833). An essay on the classification of the parasitic Hymenoptera of Britain, which correspond with the Ichneumones minuti of Linnaeus. Entomological Magazine 1: 259–276.

Johnson, N.F. (1992). Catalog of world Proctotrupoidea excluding Platygastridae. Memoirs of the American Entomological Institute 51: 1–825.

Lê, X.H. (2000). Egg-parasites of family Scelionidae (Hymenoptera). Fauna of Vietnam, vol. 3. Science and Technics Publishing House, Hanoi, 386pp.

Masner, L. (1976). Revisionary notes and keys to world genera of Scelionidae (Hymenoptera: Proctotrupoidea). Memoirs of the Entomological Society of Canada 108(97), 87pp; http://dx.doi.org/10.4039/entm10897fv

Masner, L. (1980). Key to genera of Selionidae of the Holarctic region, with descriptions of new genera and species (Hymenoptera: Proctotrupoidea). Memoirs of the Entomological Society of Canada 113: 1–54; http://dx.doi.org/10.4039/entm112113fv

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Mineo, G. (1990). Studies on the Scelionidae (Hymenoptera: Proctotrupoidea) XXXII. Revision of the Ethiopian-Oriental regions of Gryon Haliday: the letus-group. Frustula Entomologica 13(26): 89-92.

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Mineo, G. & Caleca (1994). New data on some scelionid wasps and description of new species. Phytophaga 5: 113–135.

Ohio State University (2013). http://osuc.biosci.ohiostate.edu/hymDB/eol_scelionidae.content_page?page_level=3&page_id=taxon_page_data&page_version=487&page_option1=C. Electronic version. (accessed, 22 December 2013).

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