Setodes minutus Tsuda 1942

Katsuma, Nobuyuki, 2018, The genus Setodes Rambur (Trichoptera, Leptoceridae) in Japan, Zootaxa 4407 (2), pp. 191-212 : 202-206

Setodes minutus Tsuda 1942

( Figs. 7A–7H )

Setodes minutus Tsuda 1942b , 301–302, Honshu (Kyoto); Tsuda & Akagi 1962, 135, 137, larva; Tani 1978, 24, male, Honshu (Niigata); Uenishi et al. 1993, 61, Kyushu (Fukuoka); Tanida 2005, 540, 546, 548, male; Tanaka 2012, 10, male, Honshu (Akita); Nozaki 2016, 401, male.

Setodes sp. SA: Akagi 1957, 24–25, 27, larva, Honshu (Kyoto).

Setodes curviseta Kobayashi 1959 , 350–351, Kyushu (Fukuoka). Syn. nov.

Diagnosis. Both male and female genitalia of this species are similar to those of S. pulcher Martynov 1910 distributed in Far East Russia, northern China, and North Korea. However, they are distinguishable from the latter by the following characteristics: In males, the paramere spines are elongate and gradually extend upward at the tip in lateral view in S. minutus , but they are short and curved downward at the tip in S. pulcher . In females, segment IX lacks a mid-ventral line in ventral view in S. minutus , but it is divided into 2 parts by a mid-ventral line in S. pulcher .

Adult. Head and body pale yellow. Forewings each 5.0–5.4 mm long (n = 18) in male, 5.5–6.1 mm long (n = 20) in female, covered with pale golden hairs with many silver spots. Wing venation typical for genus.

Male genitalia. Segment IX semirectangular, longitudinally shortest at middle in lateral view, long ventrally with many strong setae; dorsum of segment IX semi-trapezoidal in dorsal view, with tiny acute process at center of posterior margin. Segment X protruding triangular projection in lateral view, acute at apex, convex in dorsal view. Preanal appendages oval in lateral view, serrate in dorsal view, with many setae. Inferior appendages bilobed, mitten-like in lateral view; each with lobes round apically with short setae; upper lobe 1/2 as large as lower lobe. Phallobase semicircular in lateral view; phallicata evenly bent downward midway, tapering to acute apex; round hump produced on dorsal margin of phallicata, but sometimes lacking. Paramere spines arising from endotheca, well sclerotized, gradually upturned in lateral view, extending outward in dorsal view.

Female genitalia. Segment VIII with pair of large sternal pockets posteroventrally. Segment IX rectangular in lateral and dorsal views; sternum IX with many strong setae. Segment X semirectangular and excised apically in lateral and dorsal views, with two pairs of lobes; upper lobes slightly upturned in lateral view; lower lobe triangular in lateral view, semi-trapezoidal in dorsal view. Preanal appendages triangular in lateral and dorsal views, with many short setae. Lamellae capitate, constricted in basal 1/ 4 in lateral view, each broad and bilobed apically; upper lobe twice as large as lower lobe, semicircular in lateral view, fringed with many short setae; lower lobe triangular in lateral view, bearing 6–7 short hooked setae posteromesally. Gonopod plate fused with sternum IX, semitrapezoidal in ventral view. Spermathecal sclerite oval in ventral view, exposed posteriorly in apical 1/4.

Immature stages. Akagi (1957) described the larva and case of this species in detail (as Setodes sp. SA).

Distribution. Japan (Honshu, Shikoku, Kyushu).

Japanese name. Chibi-seto-tobikera.

Type series material examined. Right wings of a male, Kitaôji , Kyoto, 29.vi.1940, M. Tsuda ( OMNH).

Other specimens examined. Aomori: 1♀, Tsukimino, Aomori-shi, 9.vii.2011, Y. Murakami ; 1♀, Nakamori, Gonohe-machi, 7.vii.2013, Y. Murakami. Iwate: 1♂, Yakushi-gawa, Taimagura, Etsunagi, Miyako-shi, 10.viii.1994, T. Hattori . Fukushima: 3♂ 3♀, Yanohara-kougen, Showa-mura, 19.viii.2008, N. Katsuma . Niigata: 1♂, Uchinokura-gawa, Shibata-shi, 17.vii.1994, T. Hattori . Nagano: 1♂, Aoki-ko, Aoki, Taira, Omachi-shi, 28.viii.2008, N. Katsuma ; 1♀, Nakatsuna-ko, Nakatsuna, Taira, Omachi-shi, 16.ix.2008, N. Katsuma. Aichi: 3♂, Otsutani-gawa, Ichinose, Toyooka, Shinshiro-shi, 18.vii.2013, T. Ito ; 25♂3♀, Higashihirose-cho, Toyota-shi, 9.viii.2007, H. Morita. Shiga: 1♂, Kitahama, Waninaka, Otsu-shi, 18.vi.2016, S. Takeda ; 1♂ 1♀, Miyajiri, Shigaraki-cho, Koka-shi, 30.vi.2014, N. Kawase. Shimane: 1♀, Gouno-kawa, Hikishiro, Shimokuchiba, Onancho, 14.vii.2004, S. Nakamura ; 6♂ 9♀, Gouno-kawa, Nagata, Watazu-cho, Goutsu-shi, 12.vii.2004, S. Nakamura; 13♂, Gouno-kawa, Kawagoe, Sakurae-cho, Goutsu-shi, 12.vii.2004, S. Nakamura; 145♂ 118♀, Gouno-kawa, Shiki, Misato-cho, 14.vii.2004, S. Nakamura; 1♂ 5♀, Gouno-kawa, Hamahara, Misato-cho, 13.vii.2004, S. Nakamura; 19♂ 22♀, Gouno-kawa, Inbara, Kawamoto-cho, 13.vii.2004, S. Nakamura. Hiroshima: 1♂, Gounokawa, Nagaya, Yoshida-cho, Akitakata-shi, 20.vii.2004, S. Nakamura ; 8♂ 13♀, Ashida-gawa (precise locality unknown), 5.vii.2003, S. Nakamura; 5♂ 3♀, Kabe-cho, Asakita-ku, Hiroshima-shi, 14.vii.1998, S. Nakamura; 2♂ 2♀, Yuki-cho, Saeki-ku, Hiroshima-shi, 17.vii.1998, S. Nakamura; 2♂ 2♀, Minamihatajiki-machi, Miyoshi-shi, 22.vii.2004, S. Nakamura; 5♂ 3♀, Nagaya, Yosida-cho, Akitakata-shi, 20.vii.2004, S. Nakamura. Yamaguchi: 1♀, One-gawa, Miwa-machi, Iwakuni-shi, 25.ix.2000, unknown collector . Ehime: 1♂, Ibushi-rindou, Kumakogencho, 14.viii.2008, M. Takai . Kochi: 2♂ 2♀, Ananai-gawa, Shigetou, Tosayamada-cho, Kami-shi, 26.vii.2003, K. Nio ; 2♀, Shimanto-gawa, Shimanto-shi, 22.ix.2002, T. Hattori. Fukuoka: 2♂ 1♀, Yoshii-machi, Ukiha-shi, 9.iv.1962, N. Gyotoku ( CBM).

Remarks. Tsuda (1942b) described S. minutus based on 5 male specimens collected from Kitaôji-bashi, Kamogawa, Kyoto. The characteristics describing the male genitalia examined in this study are consistent with the original description and illustrations. Much of the type series material for this species was lost, except for a preparation of the right wings of a male labeled “ Setodes minuta n. sp. / Setodes sp. Kitaôji”. The size and venation of the wings are identical to those of the specimens used in this study.

Akagi (1957) illustrated Setodes sp. SA based on larvae and cases collected from Sosui, Yamashina, Higashiyama-ku (now Sosui, Yamashina-ku), Kyoto on November 1, 1942, by Tsuda. Tsuda & Akagi (1962) later associated the larva with identifiable adults of S. minutus and redescribed the former using larval illustrations which were originally labeled as Setodes sp. SA by Akagi (1957).

On the other hand, Kobayashi (1959) described S. curviseta based on 4 specimens collected from Yoshii-machi (now Yoshii-machi, Ukiha-shi), Fukuoka on June 11, 1957, by N. Gyotoku. The genitalic characteristics of this species are similar to those of S. minutus , and Uenshi (1993) suggested that this species should be a junior synonym of S. minutus . Although Kobayashi’s collections were deposited in the Natural History Museum and Institute, Chiba, I could not find any type series specimens of S. curviseta there. However, I found 2 males and 1 female specimens of S. minutus , which N. Gyotoku collected from the type locality on 9 April 1962. Therefore, I believe that S. curviseta must be a junior subjective synonym of S. minutus .

This species belongs to the Setodes pulcher Species Group ( Schmid 1987), as the morphological characteristics of the male and female genitalia are consistent with this group. Yang & Morse (1989) suggested that S. minutus and S. pulcher constitute a monophyletic group since males of both species possess outcurved paramere spines.

Figures

FIGURE 7. Setodes minutus Tsuda 1942b, A–E: male. 7A, right fore- and hind wings, dorsal; 7B–7E, male genitalia: 7B, left lateral; 7C, phallus, left lateral; 7Ca, variation of phallicata, left lateral; 7D, dorsal; 7E, ventral. 7F–7H, female genitalia: 7F, left lateral; 7G, dorsal; 7H, ventral. Scale: A = 1 mm, B–H = 500 µm.