Stactobia gunma, Ito, 2017

Ito, Tomiko, 2017, The genus Stactobia McLachlan (Trichoptera, Hydroptilidae) in Japan, Zootaxa 4350 (2), pp. 201-233 : 216-218

Stactobia gunma sp. nov.

( Figs 9 , 18 )

Diagnosis. This species belongs to the S. martynovi Species Group. The male of this species is similar to that of S tactobia hattorii in the shape of the subgenital appendages, inferior appendages, and phallus, but clearly differs from S. hattorii by the twisted shape of the inner phallic spine which is 18–20 times as long as the basal width in this species, versus 10–12 times in S. hattorii .

Description. Male ( Figs 9A–9F ). Antennae each 18-segmented and 1.2–1.4 mm long (n = 4). Length of each forewing and hind wing 2.7–2.9 mm and 2.2–2.4 mm, respectively (n = 4). Tibial spur formula 1, 2, 4.

Genitalia. Tergite VII longitudinally shorter than sternite VII, ventral process long with expanded spiny apex. Tergite VIII slightly longer than sternite VIII. Tergite IX with pair of long anterior apodemes, sternite IX reduced. Tergite X semimembranous with pair of weakly sclerotized, wide, oblique bands dorsolaterally. Subgenital appendages transversely slender with heavily sclerotized rounded apices in ventral view. Inferior appendages small, subquadrate in lateral view, M-shaped with rounded, heavily sclerotized mesal edges in ventral view. Phallus long, almost straight, slightly flattened with roundish apex; internal spine 18–20 times as long as basal width, twisted at basal 1/3, curved 40°–90° apically.

Larva. Unknown.

Type series. Holotype. Male, HONSHU, Gunma, Minakami-shi, Okutone , Hidarimata-zawa , 36˚48’ N, 139˚00’ E, 27.vi.2001, K. Endo (CBM-ZI 165997).

Paratypes. 1 male, same data as holotype (CBM-ZI 165998).

Other specimens. HONSHU. Gunma: 1 male, same data as holotype . Tochigi: 1 male, Nikko-shi, Okunikko, Toyama-zawa, 25.vi.2001, K. Endo . Kanagawa: 1 male, Yamakita-machi, Mts. Tanzawa, Nakagawa , Shiraishi-zawa , 750 m a.s.l., 3.vi.1994, TH . Yamanashi: 1 male, Oizumi-mura, Kawamata-gawa, Toryu-no-taki, 1250 m a.s.l., 11.vi.1994, TH ; 2 males, same locality, 30.v.1997, AO . Nagano: 1 male, Hase-mura, Sugishima, Shiozawa, 2.vi.1993, NK ; 5 males, Hase-mura, Okubo, small stream along Ogura-gawa , 2.vi.1993, NK . Gifu: 5 males, Kamitakara-mura, Hirayu, Okaki-gawa, 30.v.2001, K. Endo ; 2 males, Nyukawa-mura, Choshi-dani, Choshi-taki, 30.v.2001, K. Endo; 1 male, Takayama-shi, Nyukawa, Hirayu Tunnel, 20.ix.1998, HN. Shizuoka: 2 males, Shizuoka-shi, small stream along Oi-gawa , 700–750 m a.s.l., 7.viii.1994, TH . Nara: 8 males, Kawakamimura, Takahara-gawa, 850 m a.s.l., 27.v.2004, TH ; 4 males, Kami-kitayama-mura, Migimata-dani , 28v.1993, NK.

Distribution ( Fig. 18 ). Honshu (Gunma, Tochigi, Kanagawa, Yamanashi, Nagano, Gifu, Shizuoka, Nara).

Habitat. Adults of this species were collected by the above colleagues near waterfalls and rapid flowing streams.

Ethymology. The name “ gunma ” is a noun in apposition, coined from the type locality.

Japanese name. Gunma-kaku-himetobikera.

Figures

FIGURE 9. Stactobia gunma sp. nov. Male. 9 A, abdominal segments VII – X, left lateral; 9 B, abdominal segments IX – X, dorsal; 9 C, same, ventral; 9 D, phallus, left lateral; 9 E, 9 F, same, variation. Specimens: 9 A – 9 D = Gunma, Minakami-shi (type locality); 9 E = Yamanashi, Oizumi-mura; 9 F = Gifu, Kamitakara-mura. Scale bar: 0.1 mm for 9 A.

FIGURE 18. Distributions in Japan of 6 species of Stactobia.