Psilotreta kisoensis Iwata 1928
Creators: name: Kawase, Naoki
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Trichoptera
Odontoceridae
Psilotreta
Psilotreta kisoensis

description: Psilotreta kisoensis Iwata 1928
(Figs 2A–2K, 9E, 9H, 10C–D, 11B)
Psilotreta kisoensis Iwata 1928, 117–118, 125, larva, Honshu (Type locality: Nagano); Tsuda 1959, 143, larva; Botosaneanu 1970, 313–316, pl. 36, pl. 39, male, female, Honshu; Tanida 1985, 204–205, larva, case; Parker &Wiggins 1987, 35–36, larva, Honshu; Maruyama and Takai 2000, 124, pl. 119, larva, case, Honshu; Nozaki 2005, 113, larva, case, adult; Tanida 2005, 556–557, male, larva, case; Inazu and Nishida 2011, 211, male, female, larva, case, Honshu; Nozaki 2016, 87, 305, 408, 442, 451, male, Honshu; Tanida 2018, 665–667, male, larva, case.
Psilotreta armata Martynov 1933, 144–145, male, Honshu (Shiga). Synonymized by Tsuda (1942).
Diagnosis. The male and female of this species can be easily distinguished from those of other Japanese species by the venation of each forewing. The fork II is rooted on the discoidal cell in this species (Figs 2B, 2C), but petiolate in other species. Furthermore, the male of this species is distinguishable from those of other Japanese species by the genital morphology. Each lateral process of segment X lacks a ventral projection in this species (Figs 2F, 2G), but bears the ventral projections in other Japanese species. The female genitalia are characterized by the shapes of a pair of dark pigmentations of sternum IX. Each pigmentation is narrowly projected posterad and extends to a narrow posterior portion adjacent to the median shallow sulcus in ventral view (Fig. 2K). The female is also distinguishable by the shapes of the paired fin-like dorsolateral lobes that are strongly extruded posterolaterad in dorsal view (Fig. 2J). In the larva, a pair of longitudinal dark dorsal bands extending from the anterior margin of the head capsule to the posterior margin of the mesonotum are unique among known Japanese larvae.
Adult (Figs 2A–2C). General coloration black to dark brown. Length of each forewing: male 9.2–11.2 mm (mean = 10.2, n = 56), female 9.8–12.7 mm (mean = 11.8, n = 29). Head (Fig. 2A) with pair of indistinct anteromesal warts in male, distinct in female; anterior and posterior warts on each side fused into large circular wart; each narrow posterolateral wart extending ventrad along posterior margin of eye. Venation as in Fig. 2B, 2C; in forewings, fork I rooted on discoidal cell about 2/5 its length in male, 1/ 4 in female; fork II shallowly rooted; in hind wings, fork I rooted on discoidal cell about 1/2 its length in male about 1/ 3 in female, fork II shallowly rooted, crossvein m-cu present in male and female; location of fore- and hind wing coupling setae same as for P. japonica.
Male genitalia (Figs 2D–2I). Tergum IX triangular, extending posterad in dorsal view, with steep sides above basal setal warts (Figs 2D, 2F). Inferior appendages slightly shorter than preanal appendages, cylindrical with many long setae, slightly tapered; each apical segment about 2/3 length of basal segment, cylindrical with many brown teeth on apical half (Fig. 2F). Preanal appendages each leaf-shaped in lateral view, basal 1/3–1/2 broadest; apical half slightly tapered, with several long setae near rounded apex (Fig. 2F). Median dorsal process of segment X extending posterad, gradually tapered with acuminate apex in dorsal view (Fig. 2D); pair of lateral processes heavily sclerotized and with spotted granular surfaces, protruding caudad (Fig. 2D), flattened dorsally, acute apically in dorsal view (Fig. 2D), abruptly enlarged apically in lateral view (Fig. 2G); pair of intermediate appendages dark brown, heavily sclerotized, strongly curved, usually forming C-shaped structure in lateral view, each acute apex directed ventrad (Fig. 2G), or rarely posterad.
Phallus with phallotheca long, cylindrical; endotheca ventrally with pair of parameres; aedeagus with ventral surface weakly sclerotized, apex membranous, and phallotremal sclerite V-shaped in ventral view (Fig. 2I), strongly curved dorsad in lateral view (Fig. 2H).
Female genitalia (Figs 2J–2K). In ventral view, sternum IX semicircular, as long as wide; surface finely granular with pair of pigmentations (Fig. 2K); each pigmentation large oval anteriorly, with narrow posterior extension adjacent to median sulcus (Fig. 2K). Segment X with pair of dorsolateral fin-like lobes, setose dorsally; each apex strongly extruded posterolaterad in dorsal view (Fig. 2J), concave posteromesally in ventral view (Fig. 2K). Length of vaginal apparatus longer than that of segment IX (Fig. 2K).
Final instar larva (Figs 9E, 9H). Length up to 13.5 mm. Head and thoracic nota brown to reddish brown dorsally, with pair of dark longitudinal bands from anterior margin of head to posterior margin of mesonotum, and with a dark median band on the head. Among primary setae on head, setae 9, 11, 12, 14, 15 and 17 thick, brown to pale brown; other setae fine, pale or transparent; 14 longest, more than 2 times as long as 15, and 1.5 times as long as 9. Branched abdominal gills as in Fig. 9H present on each side of following segments (numbers of branches in parenthesis, n = 3): anterior dorsal gills on segments II (8–10), III (14–16), IV (16), V (14–16), VI (14–16) and VII (6–8); anterior ventral gills on segments II (6–10), III (16), IV (14–16), V (12–16), VI (12–18), VII (12–16), and VIII (8); anterior lateral gills on only III (3–5). Case same as that of P. japonica.
Specimens examined. Honshu, Aomori: 1 male, Koakagawa, Ohata-cho, Mutsu-shi, 29.vi.1999, N. Kawase; 1 male, 9 larvae, same locality, 28.vii.1999, N. Kawase. Iwate: 1 male, Matsukusazawa, Kawai, Miyako-shi, 12.vii.1997, N. Kuhara; 1 male, 1 female, Hiraniwa-kogen, Yamagata, Kuji-shi, 12.vii.1997, N. Kuhara; 8 males, Shimohata, Yamagata, Kuji-shi, 9.vii.2004, N. Kuhara. Yamagata: 5 males, 1 female, Higashi-zawa, Hirokawara, Iide-machi, 3.vii.1998, T. Hattori. Fukushima: 2 males, Funagahana-pass, Toaka, Shimogo-machi, 12.vii.1997, N. Kawase. Niigata: 1 male, 1 female, Mushi-gawa, Ôyachi, Itoigawa-shi, 8.vi.1996, T. Hattori. Fukui: 2 larvae, Irohama, Tsuruga-shi, 16.i.2003, N. Kawase. Nagano: 2 females, Chigono-sawa, Fukushima, Kiso-machi, 13.vi.1998, T. Hattori. Gifu: 6 males, Sakauchi-sakamoto, Ibigawa-cho, 7.vi.1998, T. Hattori; 1 male, Ozu, Ibigawacho, 13.v.2002, N. Kawase; 7 males, 1 female, Nishimaenotani, Tsurumi, Ibigawa-cho, N. Kawase. Shizuoka: 5 larvae, Yunoshima, Shizuoka-shi, 11.iv.1998, T. Hattori; 9 males, Terajima, Shizuoka-shi, 15.v.2002, T. Hattori. Mie: 9 males, 4 females, Miyazumakyo, Suizawa-cho, Yokkaichi-shi, 8.vi.2009, H. Morita; 4 males, 5 females, same locality, 19.vi.2009, H. Morita; 1 male, 2 females, same locality, 5.vii.2009, H. Morita; 1 female, Hachisu, Iitaka-cho, Matsusaka-shi, 27.v.2004. T. Hattori; 1 male, Tonaio, Kawahara, Hokusei-cho, Inabe-shi, 24.v.2009, H. Morita; 3 males, Ishigure-minami, Daian-cho, Inabe-shi, 26.vi–1.vii.2001, H. Morita; 8 males, 1 female, same locality, 4–8.vi.2001, H. Morita; 1 male, Nunobiki, Okubano, Iga-shi, 31.v.2009, H. Morita; 4 males, 5 females, same locality, 29.v–9.vi.2012, H. Morita; 1 male, 1 female, Komegatani, Ôuchiyama, Taiki-cho, 1.vi.1996, H. Morita. Shiga: 1 female, Kamitanakami-ohtorii-cho, Ôtsu, 19.v.2014, N. Kawase; 2 larvae, Ôishi-tomikawacho, Ôtsu-shi 2.xi.2006, N. Kawase; 1 male, Yamakado, Nishiazai-cho, Nagahama-shi, 24.v.2006, N. Kawase; 15 males, 2 females, Nakanokawachi, Yogo-cho, Nagahama-shi, 17.v–26.vi.2010, N. Kawase; 3 males, 8 females, Ôkawara, Tsuchiyama-cho, Koka-shi, 14.v–16.vi.2008, N. Kawase; 1 male, Kuroko-pass, Shiratani, Makino-cho, Takashima-shi, 20.vi.2014, S. Takeda; 1 male, 1 female, Yuzurio, Eigenji-cho, Higashiômi-shi, 31.v–26.vi.2009, N. Kawase; 2 males, 2 females, Ojigahata, Taga-cho, 1.vi.2008, H. Morita. Kyoto: 1 male, Kuta, Sakyo-ku, Kyoto-shi, 8.vi.2008, M. Aoyagi. Hyogo: 2 pupae, Kahosaka, Ôya-cho, Yabu-shi. 14.iv.2004, T. Hattori. Nara: 6 males, Kotochi, Kamikitayama-mura, 28.v.1993, N. Kuhara; 5 males, Okuchigawa, Uramukai, Shimokitayamamura, 28.v.2004, T. Hattori. Wakayama: 3 males, Hirai, Kozagawa-cho, 21.v.1990, N. Kuhara; 1 male, 1 female, same locality, 4.vi.2000, T. Ueda. Shimane: 1 female, Mt. Sentsu, Takezaki, Okuizumo-cho, 17–26.vi.2007, M. Hayashi; 1 male, same locality, 8–9.vii.2019, N. Kawase and H. Morita; 1 male, Kami-hashinami, Sada-cho, Izumoshi, 17.v.1993, N. Kuhara. Shikoku, Tokushima; 1 male, Kiyakeji, Masaki, Kamikatsu-cho. 27.v.2018, M. Aoyagi; 2 males, Kami, Sanagochi-son, 27.v.2018, M. Aoyagi and R. Toda.
Distribution and habitat. Psilotreta kisoensis is an East Palearctic species and the most common species among known Japanese Psilotreta species, widely distributed in Honshu and Shikoku (Fig. 11B). The adults and larvae are found in small mountain streams (Figs 10C, 10D).
Remarks. Tsuda (1942) synonymized Psilotreta armata with this species, but Parker & Wiggins (1987) noted that Martynov’s illustration lacks the large intermediate appendages found in the male of P. kisoensis. In this study, the author examined plenty of Psilotreta males collected from Honshu, including 23 males from Shiga Prefecture where P. armata was collected, but found no male that lacks the intermediate appendages. Additionally, most genitalic characters other than the intermediate appendages agree with those of P. kisoensis. Furthermore, the fork II in male and female forewings is sessile in P. armata (Martynov 1933, fig. 7), and only P. kisoensis shares this unique character (Figs 2B, 2C) among Japanese Psilotreta species. Therefore, the author agrees with the treatment by Tsuda (1942) even though the holotype of P. armata could not be examined.
Kawase (2021) stated that the records of P. kisoensis from Shikoku, one of the main islands of Japan, by Kuwada (1965) and Tanida (2018) were based on misidentifications of P. voluta. Although P. kisoensis was deleted from the list of Psilotreta in Shikoku at that time, the author found three males of P. kisoensis from Shikoku for the first time in the present study. On the other hand, the author could not find any specimens from Kyushu Island, another main island of Japan although Parker & Wiggins (1987) recorded this species from Fukuoka on Kyushu as “ Fukuoka Prefecture: Wakamatsu, 27.vii.1952, 1 ♂ (CNC); Sendai, 3.v.1952, 1 ♂ (CNC)”. According to the collection data of the CNC (Canadian National Collection of Insects, Arachnids and Nematodes), these two males bear the labels “ 1 male, JAPAN. (Fuk.) Wakamatsu, 27.vii.1952, K. Nagayama” and “ 1 male, JAPAN. Honshu: Sendai, 38°16’12”, N 140°52’1” E, 3.v.1952, M. Kohno”, respectively (CNC 1150853 <https://cnc.agr.gc.ca/taxonomy/Specimen. php?id=1772585> and CNC311389 <https://cnc.agr.gc.ca/taxonomy/Specimen.php?id=1772585&action=findid>). The locality name “(Fuk.) Wakamatsu” must be Wakamatsu-shi (now Aizu-Wakamatsu-shi) in Fukushima (not Fukuoka) Prefecture in northeastern Honshu because the collector, the late Mr. Koichi Nagayama, was an amateur entomologist who actively collected many insect specimens around Aizu-Wakamatsu-shi in Fukushima Prefecture (Kohno 1986). The other locality name “Honshu: Sendai” and its longitude and latitude definitely indicate that the corresponding male was collected in Sendai-shi in Miyagi Prefecture, northeastern Honshu. Thus, there is presently no reliable record of P. kisoensis from Kyushu.
Japanese name. Futasuji-kiso-tobikera.
description: Published as part of Kawase, Naoki, 2022, The genus Psilotreta Banks (Trichoptera, Odontoceridae) in Japan, pp. 501-521 in Zootaxa 5195 (6) on pages 504-507, DOI: 10.11646/zootaxa.5195.6.1, http://zenodo.org/record/7223832