Title: First Record of the Genus Seleucus Holmgren, 1860 (Hymenoptera: Ichneumonidae: Ctenopelmatinae) from the Oriental Region, with Description of a New Species

This is the accepted version of the following article: Shimizu S (2018) First record of the genus Seleucus Holmgren, 1860 (Hymenoptera: Ichneumonidae: Ctenopelmatinae) from the Oriental region, with description of a new species. Oriental Insects 52: 88–95., which has been published in final form at https://doi.org/10.1080/00305316.2017.1357054

Title: First record of the genus Seleucus Holmgren, 1860 (Hymenoptera: Ichneumonidae: Ctenopelmatinae) from the Oriental region, with description of a new species

Author: So Shimizu

Affiliation: Laboratory of Insect Biodiversity and Ecosystem Science, Graduate School of Agricultural Science, Kobe University, Rokkodaicho 1–1, Nada, Kobe, Hyogo 657–8501, Japan

ABSTRACT

The ctenopelmatine genus Seleucus Holmgren, 1860 (Hymenoptera: Ichneumonidae) is discovered from the Oriental region for the first time. A new species, Seleucus taiwanus Shimizu, sp. nov., is described, based on a single female specimen from the highlands of Taiwan.

KEYWORDS

Blasticotoma; new species; parasitoid wasp; Seleucus; Taiwan

Introduction

The genus Seleucus Holmgren, 1860 is currently placed within the tribe Seleucini Vikberg, 2000 in the ichneumonid subfamily Ctenopelmatinae Förster,1869 (Yu et al. 2016). It is comprised of a single species: S. cuneiformis Holmgren, 1860, which is distributed in the Palaearctic region from Europe (Vikberg & Koponen 2000; van Achterberg & Altenhofer 2013) to Korea (Kim et al. 2006), China (Sheng & Sun 2009, 2014) and Japan (Townes et al. 1965). Townes (1971) classified this genus in the subfamily Phrudinae; however, this classification was made without access to observations of ovipositor morphology. Based on subsequent observations of a distinct dorsal notch on the ovipositor, Kolarov (1987) transferred this genus to the ctenopelmatine tribe Mesoleiini Thomson, 1883. Finally, Vikberg and Koponen (2000) discussed the characters of Seleucus and decided that it did not fit within any of the tribes of Ctenopelmatinae, therefore they erected the monotypic tribe Seleucini. The study of van Achterberg and Altenhofer (2013) reported that the host of S. cuneiformis is the sawfly Blasticotoma filiceti Klug, 1834 (Hymenoptera: Blasticotomidae), which occurs in both the Western and Eastern Palaearctic regions. In the course of researching Taiwanese Ichneumonidae (e.g., Shimizu et al. 2016; Shimizu 2017), the present author had the opportunity to examine the ichneumonid collection at the Taiwan Agricultural Research Institute Council of Agriculture, Executive Yuan, Taichung, Taiwan (TARI), and a single specimen of Seleucus, which had not previously been recorded in Taiwan or the Oriental region, was newly discovered from the collection. Hence, in this study, the author records this genus for the first time in This is the accepted version of the following article: Shimizu S (2018) First record of the genus Seleucus Holmgren, 1860 (Hymenoptera: Ichneumonidae: Ctenopelmatinae) from the Oriental region, with description of a new species. Oriental Insects 52: 88–95., which has been published in final form at https://doi.org/10.1080/00305316.2017.1357054

Taiwan and the Oriental region, including description of a new species.

Materials and methods

The holotype specimen of Seleucus taiwanus Shimizu, sp. nov. described in the present study was from the ichneumonid collection at TARI and was examined. Specimens of S. cuneiformis from Ehime University Museum, Matsuyama, Japan (EUM) were also examined to compare to the undescribed species (see Supplementary materials). A stereoscopic microscope (SMZ1500, Nikon, Tokyo, Japan) was used for morphological observation and measurements. Multi-focus photographs for Fig. 1 were taken by single-lens reflex camera (D90, Nikon, Tokyo, Japan) with micro-lens (AF Micro-Nikkor 60mm f/2.8D, Nikon, Tokyo, Japan) and teleplus teleconvertor (N-AFD 2× Teleplus MC7, Kenoko, Tokyo, Japan) and were stacked by Zeren Stacker (image stacking software). A digital microscope (VHX- 600, Keyence, Osaka, Japan) was used for taking the photographs for Fig. 2A-D. A scanning electron microscope (SEM) (JSM-6010LV, JEOL, Tokyo, Japan) was also used for morphological observation and taking the photographs for Fig. 3A-F. The specimens for SEM observation were not coated. All figures were edited by Adobe Photoshop© Creative Cloud and Illustrator© Creative Cloud. Morphological terminology mainly follows Gauld (1991) except that the terminology for propodeal structures follows Townes (1969) and for surface microsculpture follows Eady (1968).

Taxonomy

Subfamily Ctenopelmatinae Förster, 1869 Tribe Seleucini Vikberg, 2000 Genus Seleucus Holmgren, 1860

Seleucus Holmgren, 1860: 111. Type species: Seleucus cuneiformis Holmgren, by monotypy.

Diagnosis Female adults of this genus are usually easily distinguishable from all other ctenopelmatine genera by the significantly elongated and compressed metasoma (Fig. 1) This is the accepted version of the following article: Shimizu S (2018) First record of the genus Seleucus Holmgren, 1860 (Hymenoptera: Ichneumonidae: Ctenopelmatinae) from the Oriental region, with description of a new species. Oriental Insects 52: 88–95., which has been published in final form at https://doi.org/10.1080/00305316.2017.1357054 and are also characterized by the weakly upcurved ovipositor, with a dorsal notch on middle (Fig. 3F). This genus (especially males) is sometimes confused with the cryptine species or the other ichneumonid taxa, but can be distinguished from any other ichneumonid taxa by the following combination of characters: the apex of fore tibia with a well-developed tooth on outside; fore wing vein 2m-cu straight with a single bulla; metasomal tergite 1 rather slender, broad apically, and its spiracle positioned a little behind of middle; glymma completely absent; clypeus not separated from face, inclined outwards from plane of the face, with an apical fringe of setae (Figs 2A, 3A, B); mandible broad, with two equal length teeth (Fig. 3A, B); frons with a median longitudinal carina (Figs 2A, B, 3A, C).

Distribution Oriental* and Palaearctic regions (Yu et al. 2016). *New to the Oriental region.

Biology Seleucus cuneiformis has been reared from the fern sawfly Blasticotoma filiceti (Hymenoptera: Blasticotomidae) in Europe (van Achterberg & Altenhofer 2013). Adult wasps are frequently collected on summer by Malaise traps (see Holotype and Supplementary materials data).

Seleucus taiwanus Shimizu, sp. nov. (Figs 1, 2A-D, 3A-F)

Holotype f, Taiwan: Tsuifeng, Nantou Hsien [2300 m alt.], VII. 1984, K. S. Lin & K. C. Chou leg. (Malaise trap) (TARI).

Diagnosis The new species resembles S. cuneiformis but is easily distinguishable from it by the following combination of characters: clypeus smooth (Figs 2A, 3A, B) (moderately punctate in S. cuneiformis); frons rather sparsely punctate (Figs 2A, B, 3A-C) (moderately to densely punctate in S. cuneiformis); mesoscutum, scutellum and lower half of mesopleuron smooth with setae (Figs 1, 2C, D, 3D) (moderately punctate in S. cuneiformis).

Description Holotype female. Body length ca. 8.9 mm. Head (Figs 1, 2A, B, 3A-C). Face 0.6 times as long as wide (Figs 2A, 3A), convex and smooth centrally (Figs 2A, 3A, B), diagonally wrinkled laterally (Figs 2A, 3A). Clypeus smooth (Figs 2A, 3A, B). Clypeal foveae moderately sized (Figs 2A, 3A). Malar space 0.4 times as long as basal width of mandible (Figs 2A, 3A, B). Frons and gena sparsely and finely punctate with setae (Figs 2A, B, 3A-C). Occipital carina complete, its lower end joined to hypostomal carina. Minimum length between lateral ocellus and eye 2.7 times as long as minimum length between each lateral ocellus and 2.2 times as long as maximum diameter of lateral ocellus (Figs 2B, 3C). Antenna with 25 flagellomeres. First flagellomere 1.3 times as long as second one. Scape 1.5 times as long as wide. Mesosoma entirely strongly polished and smooth, and entirely covered with setae except on propodeum (Figs 1, 2C, D, 3D). Notaulus absent (Figs 2C, D, 3D). Scutellum moderately convex, without lateral longitudinal carinae (Fig. 2C, D). Epicnemial carina complete and its upper end reaching to anterior margin of mesopleuron (Figs 2D, 3D). Propodeum rather short and evenly rounded in profile. Almost all propodeal carinae complete except the apical transverse carina. Areola and petiolar area of propodeum not separated by the apical transverse carina and transversally wrinkled. Wings. Fore wing length ca. 5.9 mm. Fore wing with areolet closed. Fore wing vein cu-a subopposite to Rs+M and inclivous. Hind wing vein cu-a intercepted below middle and Cu1 weak. Hind wing with five distal hamuli. Legs (Fig. 1). Hind femur 5.2 times as long as maximum width laterally. Ratios of hind tarsomeres as follows: 1 : 2 = 2.0, 2 : 3 = 1.5, 3 : 4 = 1.7. Metasoma entirely strongly polished and smooth (Figs 1, 3E, F). Metasomal tergite 1 rather slender with long petiole and 2.3 times as long as maximum width. Color (Figs 1, 2A-D). Head black except for mandible yellowish and antennae dark brown. Mesosoma reddish to dark brown except for mesoscutum and scutellum black. Wings hyaline. Wing venation including pterostigma dark gray. Legs yellow to yellowish brown. Metasomal tergites reddish brown. Metasomal sternites yellowish brown. Ovipositor reddish brown and its sheath yellowish brown. Male. Unknown.

Etymology The specific name is derived from the type locality.

Comments This is the accepted version of the following article: Shimizu S (2018) First record of the genus Seleucus Holmgren, 1860 (Hymenoptera: Ichneumonidae: Ctenopelmatinae) from the Oriental region, with description of a new species. Oriental Insects 52: 88–95., which has been published in final form at https://doi.org/10.1080/00305316.2017.1357054

The host of S. cuneiformis, Blasticotoma filiceti, is distributed in both the Western and Eastern Palaearctic regions, including the mountains of Taiwan (van Achterberg & Altenhofer 2013). Therefore, the discovery of Seleucus in Taiwan is not surprising. The author examined all ichneumonid specimens at TARI and at other collections of Taiwanese ichneumonids (e.g., specimens preserved at the National Institute for Agro- Environmental Sciences, Tsukuba, Japan); however, unfortunately, no additional specimens could be found. Specimens of Seleucus (including the holotype of the new species) have been collected using Malaise traps. Additional research on Taiwanese Seleucus is needed including rearing of Blasticotoma species and by collecting additional specimens using Malaise traps.

Distribution Taiwan (Nantou County).

Biology The host of S. taiwanus Shimizu, sp. nov. is unknown.

Supplementary materials Seleucus cuneiformis Holmgren, 1860 Specimens examined. f, Japan: Tochinaizawa, Hirosaki City, Aomori Pref., Honshû, 7. VII – 5. VIII. 2011, T. Nakamura leg. (Malaise trap) (EUM); f, Japan: Hitsujigaoka, Sapporo City, Hokkaido [43o 00` 27” N, 141o 24` 53” E], 4–11. VII. 2011, K. Konishi leg. (Malaise trap) (EUM); f, Japan: Hitsujigaoka, Sapporo City, Hokkaido [43o 00` N, 141o 24` E], 19–26. VII. 2007, K. Konishi leg. (Malaise trap) (EUM); 1f, 1m, Japan: Kusabue- rindö, Bifue, Hokkaido [42.7154o N, 141.2143o E], 17. VIII – 1. IX. 2012, N. Kuhara leg. (Malaise trap) (EUM); 1f, Japan: Kawaratai, Nishimeya Vil., Aomori Pref. [40o 31` N, 140o 10` E], 30. VI – 15. VII. 2013, T. Nakamura leg. (Malaise trap) (EUM); 1f, 1m, Japan: Kawaratai, Nishimeya Vil., Aomori Pref. [40o 31` N, 140o 10` E], 15–25. VII. 2013, T. Nakamura leg. (Malaise trap) (EUM).

Acknowledgements

The author would like to express his sincere thanks to three anonymous reviewers for their useful comments, as well as to Dr. Andrew M.R. Bennett (Agriculture and Agri- Food Canada, Canadian National Collection of Insects, Ottawa, Canada) for checking the This is the accepted version of the following article: Shimizu S (2018) First record of the genus Seleucus Holmgren, 1860 (Hymenoptera: Ichneumonidae: Ctenopelmatinae) from the Oriental region, with description of a new species. Oriental Insects 52: 88–95., which has been published in final form at https://doi.org/10.1080/00305316.2017.1357054 manuscript; to Dr. Chi-Feng Lee (TARI) for his kind support during investigation at TARI; and to Dr. Kenichi Ikeda (Kobe University) for his kind support during examination of specimens by SEM at Kobe University, Kobe, Japan.

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Figure legends

Figure 1. Lateral habitus of Seleucus taiwanus Shimizu, sp. nov. (holotype female). This is the accepted version of the following article: Shimizu S (2018) First record of the genus Seleucus Holmgren, 1860 (Hymenoptera: Ichneumonidae: Ctenopelmatinae) from the Oriental region, with description of a new species. Oriental Insects 52: 88–95., which has been published in final form at https://doi.org/10.1080/00305316.2017.1357054

Figure 2A-D. Partial images of Seleucus taiwanus Shimizu, sp. nov. (holotype female). A, head in frontal view; B, head in dorsal view; C, mesosoma in dorsal view; D, mesosoma in lateral view. This is the accepted version of the following article: Shimizu S (2018) First record of the genus Seleucus Holmgren, 1860 (Hymenoptera: Ichneumonidae: Ctenopelmatinae) from the Oriental region, with description of a new species. Oriental Insects 52: 88–95., which has been published in final form at https://doi.org/10.1080/00305316.2017.1357054

Figure 3A-F. SEM images of Seleucus taiwanus Shimizu, sp. nov. (holotype female). A, head in frontal view; B, head in lateral view; C, head in dorsal view; D, mesosoma in lateral view; E, metasomal segment 2 in lateral view; F, female ovipositor tip in lateral view.