Rhyacophila kobayashii Torii, 2021

Torii, Takaaki & Kobayashi, Tohru, 2021, Redescription of Rhyacophila yukii Tsuda 1942 and description of three new Rhyacophila species from Japan (Trichoptera: Rhyacophilidae), Zootaxa 4995 (3), pp. 537-550 : 543-545

publication ID	https://doi.org/ 10.11646/zootaxa.4995.3.8
publication LSID	lsid:zoobank.org:pub:8494CF5A-7C7A-42B7-8711-C87564D4B7E2
persistent identifier	https://treatment.plazi.org/id/6A5A87CE-FFDF-B03E-FF7D-7E21FD78DE69
treatment provided by	Plazi
scientific name	Rhyacophila kobayashii Torii
status	sp. nov.

Treatment

Rhyacophila kobayashii Torii n. sp.

Figs 3A–3L View FIGURE 3

Rhyacophila kisoensis: Kobayashi 1971a, p. 15 View in CoL , fig. 7, male, non Tsuda 1940.

Rhyacophila sp. ( Rhyacophila sibirica View in CoL group): Torii & Hattori 2006, p. 33, list.

Diagnosis. The male genitalia of this species are generally similar to those of other members of the Rhyacophila si- birica Group ( R. transquilla Tsuda 1940 ; R. arefini Lukyanchenko 1993 ; and R. kisoensis Tsuda 1940 ). This species can be distinguished from them by the following combination of segment X characters: (1) in dorsal view segment X is somewhat oval to spade-like; (2) in lateral view its dorsoapical portion protrudes as a beak-like structure; (3) in caudal view it is shaped like a spade with its dorsal apex incised mesally. The female vaginal apparatus of this species is similar to that of R. riedeliana Botosaneanu 1970 , distributed in Russia and Korea. However, it can be distinguished by the posterior process of the vaginal apparatus thicker at the base and thinner at the tip than for R. riedeliana .

Male. Length of each forewing 8.8–10.1 mm (n = 6). Specimens in alcohol with head, thorax, and wings dark brown; legs yellowish brown, with spurs dark brown. All abdominal segments without thin spur ventrally.

Male genitalia ( Figs 3A–3F View FIGURE 3 ). Segment IX in lateral view subrectangular, with dorsal portion longer than ventral portion. Segment X in lateral view with dorsoapical portion protruding beak-like, in dorsal view somewhat oval to spade-like with apicomesal notch, in caudal view with its dorsal apex incised mesally. Apical band of aedeagus (a.b.) in lateral view long and narrow, bar shaped. Dorsal branch of aedeagus (d.b.a.) in lateral view cylindrical and protruding. Ventral branch of aedeagus (v.b.a.) in lateral view cylindrical and protruding. Aedeagus (aed.) in lateral view slender, spine-like, curved caudad. Ventral lobe of aedeagus (v.l.a.) elliptical in dorsal view. Basal segment of each inferior appendage (b.i.a.) somewhat trapezoidal in lateral view, in ventral view with its inner margin slightly concave and outer margin straight; apical segment of each inferior appendage (a.i.a.) in lateral view with apex depressed obliquely and its upper apex shallowly incised, in ventral view with its mesal margin nearly straight and lateral margin straight.

Female. Length of each forewing 9.7–9.8 mm (n = 2).

Female genitalia ( Figs 3G–3J View FIGURE 3 ). Segments IX, X, XI often retracted into the segment VIII ( Fig 3G View FIGURE 3 ). All abdominal segments without thin spur ventrally. Tergum and sternum of segment VII with rounded corners. Segment VIII cone shaped. Segment IX membranous and trapezoidal, its proximal part slightly wider than distal edge. Segment X trapezoidal. Segment XI with pair of cerci (c.). Apodemal rods from segment VIII (ap.r.VIII) extending into segment VII. Apodemal rods from segment XI (ap.r.XI) almost same length as those of segment VII. Posterior process of vaginal apparatus (p.pr.) in dorsal view is long lozenge-shaped, in lateral view elongate, bar-shaped, with center constricted.

Immature stages. Unknown.

Holotype. Male, Shinohara-gawa, Makino , Sagamihara-shi , Midori-ku , Kanagawa (35.5926°N, 139.1717°E, 270 m a.s.l.), 21.iv.2020, T. Takaaki, sweep ( SEHU). GoogleMaps

Paratypes. 6 males, 5 females, Warashina-gawa, Yunoshima, Aoi-ku , Shizuoka-shi , Shizuoka, 11.v.2001, T . Hattori ( SEHU) ; 5 males, same data as holotype ( CBM) GoogleMaps .

Other material examined. 2 males, Fujikuma-gawa, Tanzawa-horiyama, Hadano-shi, Kanagawa, 9.v.2007, T . Nozaki; 1 male, Utouge-no-taki, Fujieda-shi, Shizuoka, 6.v.2006, T . Takaaki, sweep; 3 males, 6 females, Nishigouchi-gawa, Yokosawa, Shizuoka-shi, Aoi-ku , Shizuoka, 4.v.1995, T . Hattori ( SPMN) ; 2 males, 1 female, Yuyamagawa, Yuyama, Aoi-ku, Shizuoka-shi , Shizuoka, 29.iv.1997, T . Hattori ( SPMN) ; 3 males, 2 females, Yokimatagawa, Yunoshima, Aoi-ku, Shizuoka-shi , Shizuoka, 11.iv.1998, T . Hattori ( SPMN) ; 1 female, Sakubadaira-bashi, Ichinose-gawa, Enzan-shi, Yamanashi, 22.v.1999, T . Hattori ( SPMN) ; 2 males, Doryuno-taki, Ohizumi-mura, Yamanashi, 30.v.1997, T . Hattori ( SPMN) ; 1 male, 2 females, Funabara-gawa, Izu-shi, Shizuoka, 18.v.1996, T . Hattori ( SPMN) ; 5 males, Nagao-gawa, Hirayama, Aoi-ku, Shizuoka-shi, Shizuoka, 27.iv.2006, T . Hattori; 9 males, 1 female, Abe-toge, Umegashima, Aoi-ku, Shizuoka-shi , Shizuoka, 5.vi.1999, T . Hattori ( SPMN) ; 7 males, Abe-toge, Umegashima, Aoi-ku, Shizuoka-shi, Shizuoka, 18.vi.2001, T . Hattori ( SPMN) ; 1 male, Ikawa-toge, Umegashima, Aoi-ku, Shizuoka-shi, Shizuoka, 21.vi.2003, T . Hattori ( SPMN) ; 10 males, 10 females, Kurobe-zawa, Hirano, Aoiku, Shizuoka-shi , Shizuoka, 29.iv.1994, T . Hattori ( SPMN) .

Etymology. The new species is named in honor of the late Mr. Mineo Kobayashi, who first illustrated this species as “ R. kisoensis ”.

Distribution. Japan (Honshu).

Habitat. The type locality is a small, narrow, mountain stream. The rivers at the other collecting sites were 5–10 m wide, with bottoms consisting of boulders of different sizes, pebbles, and leaf litter, and with steep banks. Water was clear, colorless, transparent, and odorless.

Remarks. This is the same species as “ R. kisoensis ” figured by Kobayashi (1971a; Figs 4K, 4L View FIGURE 4 ) because the morphology of the male genitalia, especially the shape of segment X, is identical to that of this species.

Japanese name. Kobayashi-nagare-tobikera.