Document Type : Research Article
Graphical Abstract
Epitranus longicaudatus: A new species of chalcidid wasps (Hymenoptera: Chalcididae, Epitraninae) from southern India
C. Binoy
Insect Ecology and Ethology Laboratory, Department of Zoology, University of Calicut, Kerala-673635, India.
https://orcid.org/0000-0003-4309-5460
S. Santhosh
Systematic Entomology Laboratory, Malabar Christian College, Kozhikode, Affiliated to University of Calicut, Kerala-673001, India.
https://orcid.org/0000-0002-4999-1971
M. Nasser
Insect Ecology and Ethology Laboratory, Department of Zoology, University of Calicut, Kerala-673635, India.
https://orcid.org/0000-0002-6460-1839
ABSTRACT. A new species, Epitranus longicaudatus sp. nov., is described with illustrations from South India, expanding the genus Epitranus Walker to 73 species globally and 18 from India. The new species is compared with the congeneric species E. salinae Narendran, originally described from Malaysia. Both E. longicaudatus sp. nov. and E. salinae are easily identified within the monotypic subfamily in having large metasoma, more than twice as long as petiole and having gastral terga following the first, telescopic and retracted beneath the first. E. salinae is also diagnosed and illustrated using digital images for the first time. These two species complex is the largest of all described Epitranus.
Keywords: Chalcidoidea, Malaysia, parasitoid, Oriental, nomenclature, taxonomy
Citation: Binoy, C., Santhosh, S. & Nasser, M. (2024) Epitranus longicaudatus: A new species of chalcidid wasps (Hymenoptera, Chalcididae, Epitraninae) from southern India. Journal of Insect Biodiversity and Systematics, 10 (4), 737–745.
INTRODUCTION
Members of the monotypic subfamily Epitraninae, represented by the singular genus Epitranus Walker can easily be identified from its congeneric chalcidids by its petiolate body and shielded clypeus (Binoy et al. 2021). Bouček (1982), Husain & Agarwal (1981) and Narendran (1989) provided voluminous works on the species of the genus from the Oriental region in addition to the revision of the family from Vietnam by Narendran & van Achterberg (2016). The monophyly of the subfamily is unambiguously supported by varied character states, most peculiar of which is the head with frontal lobe below antennal toruli forming a shield over clypeus, gaster strongly bulging ventrally and the shallow antennal scrobes often delimited laterally by faint carinae. The genus presently contains 72 valid species (UCD community, 2023), but type examinations are understood to lower the number (Gérard Delvare, unpublished data). Members of the genus are mostly encountered in the tropical regions of the Old World (Afrotropical realm: Schmitz, 1946; Steffan, 1957, and Indopacific realm: Habu, 1960; Bouček, 1982, 1988; Narendran, 1989; Narendran & van Achterberg, 2016). Few species of Epitranus were also recently discovered in the Palaearctic region (Fakhrzadeh et al., 2021). The New World reports of the genus possibly point to the introduction of the parasitoid with their respective stored pest host (Bouček, 1982). Koutsoukos and Delvare (2021) confirm the occurrence of the genus from Europe. Nevertheless, host data on the genus are scarce except for the report from small moths of families Crambidae, Pyralidae and Tineidae as hosts (Bouček, 1982). Binoy et al. (2021, 2022) reared E. uterellophagus Binoy & Santhosh from household case bearer Phereoeca uterella (Walsingham, 1897) (Lepidoptera: Tineidae) from South India. Apart from this, two species of Epitranus are reported as myrmechopiles or termitophiles collected from nests of these social insects (Narendran, 1989; Rasplus, 1993). Here we describe with illustrations a new species of Epitranus from south India, distinguished easily by the presence of a long gaster, closely resembling a Malaysian species, E. salinae Narendran, 1989.
MATERIAL AND METHODS
The new species was collected from the Botanical Garden at the University of Calicut (11°08'01.6"N & 75°53'26.5"E, 105m) in the Malappuram district of Kerala, India using a Malaise trap. Further expeditions to collect additional samples did not materialize, and this description is based on the specimen collected and here designated as holotype. The specimen was transferred to 70% ethyl alcohol and card-mounted for microscopic observations. The specimen was examined under Leica® M205A stereo-zoom microscope and images were taken using Leica® S8 APO attached to a Leica® DFC 2900 digital camera attached to the stereomicroscope. Measurements of the specimens were obtained using Leica® LAS (Leica® Application Suite V4.7.1) microsystems by Leica® (Heerburg, Switzerland). Images at varying depths were stacked into a single image using Leica® Automontage Software V4.2 and final illustrations were post-processed for contrast and brightness using Adobe Photoshop® CS5 (Version 6.1). The type specimen is deposited in the collections of the Systematic Entomology Laboratory, Malabar Christian College, Calicut. A distribution map of the species of long-tailed species of Epitranus occurring in the Oriental Region was constructed using ArcGIS Online by Environmental Systems Research Institute, Redlands, California (Esri, 2024) (Fig. 18). The new species was initially identified using the Oriental key to species (Narendran, 1989) and further compared with digital images of the holotype of photographs of closely related type species, Epitranus salinae Narendran, 1989 (No. 3111) (Figs 11–17) made available from the American Entomological Institute, Utah USA (AEI) (Dr James Pitts, curator) for comparative morphological analysis.
Terms and measurements. The terminology used is mainly that of Binoy et al. (2021) and Yoder et al. (2010). The general abbreviations of the terms are as follows: fux – funiculars, x being the funicle number; mv – marginal vein; OD – diameter of median ocellus; OOL – oculo-ocellar distance; POL – post-ocellar distance; stv – stigmal vein; Gtx – gastral tergites, x being the tergite number.
RESULTS
Taxonomic hierarchy
Order Hymenoptera Linnaeus, 1758
Superfamily Chalcidoidea Latreille, 1817
Family Chalcididae Latreille, 1817
Subfamily Epitraninae Burks, 1936
Genus Epitranus Walker, 1834
Epitranus Walker, 1834:21, 26. Type species: Epitranus fulvescens Walker, by monotypy.
Narendran & van Achterberg (2016:102) provides the list of complete synonymies, hence not repeated here.
Amended Key to Oriental Species of Epitranus Walker (from Narendran, 1989)
31 .. Gaster with epipygium long, longer than half pre-epipygial part of gaster (excluding petiole) (Figs 1, 11). ......................................................................................................... 32
—.... Characters not as above. ........................................ 33 (couplet 32 in Narendran, 1989)
32 .. Clypeus tridentate (Fig. 15, arrow head); Gt1 2.9´ length of petiole (Fig. 11). E. salinae Narendran
—.... Clypeus edentate (Fig. 3, inset); Gt1 2.2´ as long as petiole (Fig. 1). E. longicaudatus sp. nov.
Epitranus longicaudatus Binoy sp. nov. (Figs 1–10)
https://zoobank.org/urn:lsid:zoobank.org:act:748BB3B4-62C5-4D18-8C4B-FE360AC9F3BA
Type material. Holotype ♀, India: Kerala, Malappuram district, Botanical Garden, University of Calicut (11°08'01.6"N, 75°53'26.5"E, 105m above MSL), Malaise Trap, 1.iii.2018–2.iv.2018, Coll. C. Binoy.
Etymology. The species name is derived from Latin longicauda (long-tail), in reference to the long acuminate gaster of the new species.
Diagnosis. The new species resembles E. salinae in general morphology and runs close to it in the key to Oriental species of Epitranus (Narendran, 1989) in having epipygium distinctly long, last sternite plough shaped, propodeum with a small and often raised areola followed by a median carina, and gastral apex acuminate in profile. Epitranus longicaudatus Binoy sp. nov. differs from E. salinae as follows: Gt1 long, twice as long as epipygium (in E. salinae epipygium longer than half length of Gt1 (Fig. 11)); hind femur deep reddish brown, no median black patch (in E. salinae, hind femur with distinct median black patch (Fig. 16)); Gt1 2.2´ as long as petiole (in E. salinae first tergite 2.9´ length of petiole) (Fig. 12); clypeus edentate (in E. salinae, clypeus with three well-formed teeth) (Fig. 15, arrow head).
Description. ¾ Holotype ♀ (Figs 1–10). Body length 5.08 mm, length of fore wing 2.44 mm. Body black except following parts: eyes pale golden yellow with black patches, ocelli reddish brown, scape, pedicel and ring segment reddish brown, following segments darker; tegulae rufous; wings hyaline with brown veins; fore and mid legs brown, hind coxa brown-black with apical third red-brown, hind femur red-brown with moderate white pubescence, ventrally with basal one largest followed by seven short black teeth, hind tibia red-brown with pale yellow sub-basal tooth, all tarsi rufous; pubescence on thorax pale golden yellow; metasoma deep red-brown with ovipositor sheath black.
Head. Head with dense setigerous punctures, wider than mesoscutum in dorsal view (1.2´), distinctly transverse (1.6´ as wide as high in frontal view); scrobe 1.5´ as long as wide with weak striae (Fig. 3). Vertex finely densely punctate between, interspaces smooth, POL 1.4´ OOL. Preorbital carina weakly indicated; malar area densely finely punctate; malar space 0.43´ as long as eye height in lateral view; malar carina absent; gena with coarse setigerous punctures; post-orbital carina indicated. Occipital area finely densely punctate, interspaces wide, smooth; occipital carina, just above foramen magnum. Frontal lobe very short, not masking clypeus, with free margin entire (Fig. 3 inset). Antenna. 12 antennomeres with sparse short setae; scape relatively long not reaching median ocellus, as long as fu2 to fu6 combined; pedicel sub-cylindrical; anellus transverse; clava bluntly tapered apically, 2.2´ as long as wide. Flagellomeres (except the first) bearing mostly a single row of MPS; relative length of antennomeres in the ratio 5.5: 1.1: 1.1: 1.2: 1.2: 1.1: 1.1: 1.1: 1.2: 3.1.
Mesosoma. Pronotum and mesoscutum dorsally with close pits, interstices wide, sparse yellow pubescence; diameter of the pit on mesoscutum increases posteriorly; mesoscutellum as long as wide with wide pits, single pale golden yellow seta arising from each pit; median short carina on anterior scutellar margin; mesoscutellum rounded apically (Fig. 5); propodeum with small areola anteriorly followed by raised median carina accompanied by sublateral carinae (Fig. 6); lower episternum ending in blunt notches ventrally before insertion of hind coxa (Fig. 7, arrow head); Wings. Hyaline, with sparse short scattered setae on lamina, mv long, bending in a curve forming small stv (Fig. 8); Hind leg. Hind femur matt with dense brown setae, ventrally with basal tooth large, sharp, followed by seven regularly placed black teeth; hind tibia ventrally with grove, with subbasal hump and a sharp tooth (Fig. 9).
Metasoma. Metasoma long, 1.6´ as long as mesosoma; petiole red-brown, long and arching 3.9´ as long as broad, 5.3´ as long as high with carinae on dorsal and lateral margins in lateral view (Fig. 6); terga with sparse pubescence ventro-laterally, base bulging ventrally inwards, apically acuminate, Gt1 as long as 0.7´ total length of metasoma (including epipygium), 2.5´ as long as petiole; Gt2 0.3´ as long as Gt1; Gt3–Gt6 small, retracted or partially behind Gt1; epipygium very long, as long as 0.5´ length of Gt1; ovipositor sheath black, visible dorsally (Fig. 10).
Male. Unknown.
Host. Unknown.
Distribution. India: Kerala.
Figures 1–10. Epitranus longicaudatus Binoy sp. nov. Holotype ♀. 1. Habitus, lateral view; 2. Habitus, dorsal view; 3. Head, frontal view, clypeus enlarged in inset; 4. Head, lateral view; 5. Head and mesosoma, dorsal view; 6. Propodeum and petiole, dorsal view; 7. Petiole, lateral view (arrow head showing apical notches on episternum); 8. Fore wing; 9. Hind leg; 10. Metasoma, dorsal view.
Figures 11–17. Epitranus salinae Narendran, 1989, Holotype ♀. 11. Habitus, lateral view; 12. Habitus, dorsal view; 13. Head, frontal view; 14. Head, mesosoma and petiole, dorsal view, arrow head showing antero-medial depression on mesoscutellum; 15. Clypeus, arrow head showing clypeal dentation; 16. Hind leg; 17. Type labels.
Epitranus salinae Narendran, 1989 (Figs 11–17)
Type Material examined [images]. Holotype, ♀ Malaysia, Negris, Pasoh For. Res. Coll. P.&M. Baker, 22.xii.1978 [AEI].
Diagnosis. Black specimen except following parts: scape, pedicel, fu1, fore and mid legs testaceous, hind coxa black with apex red-brown, hind femur brown with conspicuous medial black patch, femoral teeth black, wings hyaline, venation pale brown, metasoma pale brown, pale yellow-brown below. Frons and vertex closely punctate, interstices smooth; scrobe weakly striated; toruli situated on produced clypeal shield (Fig. 13). Clypeus produced, distinctly tridentate apex (Fig. 15, arrow head); POL almost twice as long as OOL; occiput similarly pitted, interstices smooth; antenna with scape, not reaching front ocellus. Mesosoma with close umbilicate pits, interstices smooth and shiny; mesoscutellum with basal area slightly sunken medially (Fig. 14, arrow head), apex rounded; fore wing with mv apically curved into short stv. Hind coxa polished dorsally, sparsely pitted and pubescent ventrally; hind femur more than twice as long as broad, surface distinctly pubescent; ventral margin with nine irregular teeth, basal tooth large, disc moderately pubescent; hind tibial hump with a single large tooth, not crenulate (Fig. 16); metasoma Gt1 2.9´ medial length of petiole; remaining terga telescopic within Gt1; epipygium long, more than half of Gt1 (Fig. 11, 12).
Male. Unknown.
Host. Unknown.
Distribution. Malaysia: Negeri Sembilan state (Pasoh Forest Reserve).
DISCUSSION
The close morpho-taxonomic relationship between E. longicaudatus Binoy sp. nov. and E. salinae highlights an interesting biogeographical pattern. The geographic separation of South India and Malaysia suggests a historical dispersal or vicariance event that led to the divergence of these species (Fig. 18).
Figure 18. Distribution map of long-tailed Epitranus from the Oriental region.
The divergence of these species likely occurred due to geographic isolation and subsequent adaptation to distinct ecological niches. The adult parasitoids are known to be feeding primarily on honeydew, pollen or nectar (and host haemolymph rarely) (Jervis & Kidd, 1986). Modifications on clypeus, a structure used extensively in burrowing/ digging wasps (Crabronidae) while seen as tridentate on
E. salinae and edentate on E. longicaudatus Binoy sp. nov. point to the ecological advantage of the archipelago species over its Indian counterpart. Host associations of these parasitoids are thus necessary to clarify the distributions as well as the varying ecology role played by them in geographical isolations.
AUTHOR′S CONTRIBUTION
The authors confirm their contribution to the paper as follows: C. Binoy: study conception and design, specimen collection and assembling, analysis and interpretation of results, and drafting the manuscript; C. Binoy, S. Santhosh & M. Nasser: Commented and reviewed the manuscript. All authors reviewed the results and approved the final version of the
FUNDING
This research received no specific grant from any funding agencies.
AVAILABILITY OF DATA AND MATERIAL
The specimens listed in this study are deposited in the collections of Systematic Entomology Laboratory, Malabar Christian College, Calicut and are available from the curator, upon request.
ETHICS APPROVAL AND CONSENT TO PARTICIPATE
This study only included plants and arthropod material, and all required ethical guidelines for the treatment and use of animals were strictly adhered to in accordance with international, national, and institutional regulations. No human participants were involved in any studies conducted by the authors for this article.
CONSENT FOR PUBLICATION
Not applicable.
CONFLICT OF INTERESTS
The authors declare that there is no conflict of interest regarding the publication of this paper.
ACKNOWLEDGMENTS
The authors are thankful to authorities at the Department of Zoology, University of Calicut and P.G. & Research Department of Zoology, Malabar Christian College Calicut for encouragement and facilities. The authors are thankful to Brandon Claridge (PhD biology student, Utah State University) and Dr James Pitts (American Entomological Institute, Utah, U.S.A.) for providing a digital loan of type specimen E. salinae for comparative analysis. The study was carried out during the PhD of CB at the University of Calicut, financially supported by UGC by means of NFSC. SS thankfully acknowledges SERB, Department of Science and Technology, Govt. of India, New Delhi (File No. EMR/2017/005528) for financial assistance.
REFERENCES
Binoy, C., Santhosh, S., Nasser, M. & Jyolsna, K. (2021) A new report on the parasitisation of Epitranus Walker (Chalcidoidea: Chalcididae) on Phereoeca uterella (Walsingham) (Lepidoptera: Tineidae) with the description of a new species from India. Oriental Insects, 55 (4), 475–483. https://doi.org/10.1080/00305316.2020.1838965
Binoy, C., Santhosh, S. & Nasser, M. (2022) Chalcidid parasitoids (Hymenoptera, Chalcididae) of Phereoeca uterella (Walsingham) (Lepidoptera, Tineidae): description of a new species and the male of Epitranus uterellophagus from southern India. Systematic Parasitology, 99, 1–11. https://doi.org/10.1007/s11230-021-10011-7
Bouček, Z. (1982) Oriental chalcid wasps of the genus Epitranus. Journal of Natural History, 16, 577–622. https://doi.org/10.1080/00222938200770451
Bouček, Z. (1988) Australasian Chalcidoidea (Hymenoptera) – A biosystematic revision of genera of fourteen families, with a reclassification of species. CAB International, Wallingford. 832 p.
Esri (2024) «Imagery» Basemap. Scale Not Given. «World Imagery». 12 December 2009. Available from: https://www.arcgis.com/home/item.html?id=10df2279f9684e4a9f6a7f08febac2a9 [Accessed 10 June 2024]
Fakhrzadeh, N., Lotfalizadeh, H. & Delvare, G. (2021) Extending Afrotropical endemism: two species of Epitranus Walker, 1832 (Hymenoptera: Chalcididae) in the Palaearctic region. Oriental Insects, 55 (2), 191–203. https://doi.org/10.1080/00305316.2020.1767707
Habu, A. (1960) A revision of the Chalcididae (Hymenoptera) of Japan with description of sixteen new species. Bulletin of National Institute of Agricultural Sciences, Tokyo, Series, 11, 131–363.
Husain, T. & Agarwal, M.M. (1981) Taxonomic studies on Indian Epitraninae (Hymenoptera: Chalcididae). Oriental Insects, 15 (4), 413–432. https://doi.org/10.1080/00305316.1981.10434340
Gadallah, N., Soliman, A. & Al Dhafer, H. (2020) First record of the subfamily Epitraninae from Saudi Arabia (Hymenoptera, Chalcidoidea, Chalcididae), with the description of three new species. ZooKeys, 979, 35–86. https://doi.org/10.3897/zookeys.979.52059
Jervis, M.A. & Kidd, N.A.C. (1986) Host-feeding strategies in hymenopteran parasitoids. Biological Reviews, 61, 395–434. https://doi.org/10.1111/j.1469-185X.1986.tb00660.x
Koutsoukos, E. & Delvare, G. (2021) First record of the subfamily Epitraninae (Hymenoptera: Chalcididae) in the European Continent. Travaux du Muséum National d’Histoire Naturelle “Grigore Antipa”, 64 (1), 61–65. https://doi.org/10.3897/travaux.64.e66165
Narendran, T.C. (1989) Oriental Chalcididae (Hymenoptera: Chalcidoidea). Zoological Monograph. Department of Zoology, University of Calicut, Kerala, 441 p.
Narendran, T.C. & van Achterberg, C. (2016) Revision of the family Chalcididae (Hymenoptera: Chalcidoidea) from Vietnam, with the description of 13 new species. Zookeys, 576, 1–202. https://doi.org/10.3897/zookeys.576.8177
Rasplus, J.-Y. (1993) L’entomofaune de termitière morte de Macrotermes. Description d’une nouvelle espèce de Spalangia et note sur une espèce rare d’Epitranus (Hymenoptera, Pteromalidae, Chalcididae). Revue Française d’Entomologie (Nouvelle Série), 15 (2), 81–84.
Schmitz, G. (1946) Chalcididae (Hymenoptera Chalcidoidea). Exploration du Parc National Albert, Mission G. F. de Witte (1933–1935). Fascicule 48. Institut des Parcs Nationaux du Congo Belge, Bruxelles, 191 p. + 17 plates.
Steffan, J.R. (1957) Epitraninae (Hym. Chalcididae) du Musée Royal du Congo Belge. Revue de Zoologie et de Botanique Africaines, 56 (1/2), 71–91. [in French]
UCD Community (2023) Universal Chalcidoidea Database Website. Available from: https://ucd.chalcid.org [Accessed 31 March 2024]
Walker, F. (1834) Monographi Chalciditum (continued.). Entomological Magazine, 2 (1), 13–39.
Yoder, M.J., Mikó, I., Seltmann, K.C., Bertone, M.A. & Deans, A.R. (2010) A gross anatomy ontology for Hymenoptera. PLoS ONE, 5 (12), e15991. Available from: http://glossary.hymao.org [Accessed 13 May, 2024]
