Homoplectra gracilis, Nozaki, 2019

Nozaki, Takao, 2019, Descriptions of five new species of Homoplectra Ross (Trichoptera, Hydropsychidae) from Japan with reassignment of Homoplectra tohokuensis (Kobayashi), Zootaxa 4608 (2), pp. 329-344 : 339-343

Homoplectra gracilis sp. nov.

( Figs. 6 , 9 )

Diplectroninae gen. sp.: Kugo & Nozaki 1991, 7; Nozaki & Nakamura 2002, 171.

Diplectroninae gen. sp. 1: Inazu 2008, 76; Inazu 2012, 8.

Homoplectra sp. A: Nojima 2017, 119.

Diagnosis. The male of this species is easily distinguishable from other congeneric Japanese species by the narrow apices of the inferior appendages. The female is distinguishable from those of known Japanese species by the ovoid concavity on the vulval scale.

Adult. General appearance in alcohol similar to that of H. crassa . Forewings each 9.5–12 mm long in male (n = 10), 10.5–12.5 mm long in female (n = 8).

Male genitalia. Sternum IX triangular in lateral aspect, with large triangular posteroventral lobe in ventral aspect. Tergum IX round posteriorly in dorsal aspect, broadly fused with segment X laterally. Segment X weakly sclerotized dorsally, bilobed in dorsal aspect, with pair of membranous bulges posteroventrally, each lobe with stout posterior process arising from posteroventral margin and parallel with margin. Inferior appendages with spine-like setae along apical 1/5–1/7 ventromesally, each with tapered apex in lateral aspect, ventromesal apex very slightly bulging subapically and with short spine-like setae. Phallotheca large with posterodorsal processes forceps-like in dorsal aspect, with round shoulders at midlength; pair of lateral processes of phallotheca long, slender, gradually curved ventrad, each with single apical spine surrounded by hair. Aedeagus with short head; pair of dorsolateral processes long, each with apex directed dorsad and having single stout spine surrounded by hair; ventral process divided into two lobes at 2/3–3/4 distance from base, each with single spine and hair apicodorsally, directed posterodorsad.

Geographic variations in male genitalia. Males collected from Hiruzen-shitao, Maniwa-shi, Okayama Prefecture have the same genitalic characters as those collected from the type locality, but other males are variable in the shape of segment X ( Fig. 6F ) and the shape and/or length of the phallic processes (e.g., Figs. 6 G– 6I).

Female. Segment IX oblique in lateral aspect, mucronate posteriorly in dorsal aspect, anteroventral projections blade-shaped in lateral aspect. Segment X forming oblique parallelogram. Vulval scale large, with central ovoid concavity. Vaginal apparatus rectangular in ventral aspect, but with suddenly narrower anterior 1/4 protruding into segment VII.

Immature stages. unknown.

Holotype. Male (in alcohol). Okuyoshihara, Akaiwa-shi , Okayama, 34.7799°N, 134.1420°E, alt. 78 m, 20.v.2018, K. Nojima ( CBM-ZI 0167088 ).

Paratypes. 2 males, same data as holotype ( CBM-ZI 0167089–0167090 ) ; 1 male, 1 female, Yamanori-yama, Hiruzen-shitao, Maniwa-shi, 35.2316°N, 133.8093°E, 16.vii.2016, K. Nojima ( CBM-ZI 0167091–0167092 ) .

Other specimens examined. Hyogo: 1 female, Omenno-taki, Shinonsen-cho , 12.viii.1989, K. Kugo ; 1 female, Ougino-sen, alt. 900 m, Shinonsen-cho , 11.vii.2004, K. Inazu ; 1 male, Okubo, Sekinomiya, Yabu-shi , 19.viii.2017, K. Inazu ( KI) ; 1 female, Bekku, Sekinomiya, Yabu-shi , 11.ix.2011, K. Inazu ( KI) ; 1 male, 1 female, Hachibusekogen, Sekinomiya, Yabu-shi , 20.vii.2010, K. Inazu ; 1 male, Choshiga-tani, Muraoka-ku, Kami-cho , 7.vii.2004, K. Inazu ( KI) ; 1 female, same locality, 2.vii.2006, K. Inazu ( KI) . Okayama: 1 male, Hiruzen-kamifukuda, Maniwa-shi , 12.vii.2003, M. Takai ; 1 male, Yamanori-yama, Hiruzen-shitao, Maniwa-shi , 35.2316°N, 133.8093°E, 16.vii.2016, K. Nojima, ( KN) ; 1 male, 1 female, Hade-nishidani, Kagamino-cho , 22.vii.2012, K. Nojima ( KN) ; 1 male, Oogaya, Nishiawakura-son , 24.vii.2016, K. Nojima ( KN) ; 1 male, Mabicho-yata, Kurashiki-shi , 25.vi.2012, K. Nojima ( KN) ; 1 male, Kitagishima-cho, Kasaoka-shi , 12.v.2018, K. Nojima ( KN) . Hiroshima: 1 female, Yasaka-dam, Kuritake-cho, Otake-shi , 28.vii.2000, S. Nakamura ; 1 female, Hosomi-dani, Yoshiwa, Hatsukaichi-shi , 17.vii. –13.ix.2005, I. Mori .

Etymology. The specific epithet (Latin adjective, “slender”) refers to the slender apex of each inferior appendage.

Distribution. Honshu (west).

Habitat. At the type locality, a small stream (2–3 m width) gently flowing in a forest (Nojima personal communication on 31.v.2018).

Japanese name. Hosoo-nisemiyama-shima-tobikera

Figures

FIGURE 6. Adults of Homoplectra gracilis sp. nov. 6A–6E male genitalia, type locality (Okayama, Akaiwa-shi): 6A, left lateral; 6B, dorsal, 6C, ventral, apex of right inferior appendage enlarged; 6D, phallic apparatus, left lateral; 6E, phallotheca, dorsal. 6F–6I, male genitalia, variations: 6F1, segments IX and X, left lateral, Okayama (Kagamino-cho); 6F2, same, Hyogo (Yabu-shi); 6F3, same, Okayama (Kurashiki-shi); 6F4, same, Okayama (Hiruzen-kamifukuda); 6G1, phallic apparatus, left lateral, Okayama (Kagamino-cho); 6G2, same, Hyogo (Yabu-shi); 6G3, same, Okayama (Kurashiki-shi); 6G4, same, Okayama (Hiruzen-kamifukuda); 6H1, phallotheca, dorsal, Okayama (Kagamino-cho); 6H2, same, Hyogo (Yabu-shi); 6H3, same, Okayama (Kurashiki-shi); 6H4, same, Okayama (Hiruzen-kamifukuda); 6I1, ventral process of aedeagus, ventral, Okayama (Kagamino-cho); 6I2, same, Hyogo (Yabu-shi); 6I3, same, Okayama (Kurashiki-shi); 6I4, same, Okayama (Hiruzen-kamifukuda). 6J–6L, female genitalia, Okayama (Hiruzen-shitao): 6J, left lateral; 6K, dorsal; 6L, ventral.

FIGURE 9. Distributions of Homoplectra species in Japanese main islands.