Homoplectra crassicornea Nozaki and Ito, 2018

Ito, Tomiko & Nozaki, Takao, 2018, The family Hydropsychidae Curtis (Trichoptera) in the Ryukyu Archipelago, southwestern Japan, Zootaxa 4504 (4), pp. 545-565 : 551

Homoplectra crassicornea Nozaki and Ito sp. nov.

( Figs 4 A– 4I)

Homoplectra sp.: Kuhara and Ito 2017, 15, Yaku-shima.

Diagnosis. The male of this species can be recognized readily by its aedeagus having a pair of ventral processes as compared to a single ventral process with a bifid apex in other known males ( Weaver 1985, Ruiter 2003, Malicky 2015). The female of this species can be distinguished from that of H. trifurcata sp. nov. by the shape of the lateral lobe of the sternite VIII in lateral aspect: The posterodorsal corner of each lobe is round in this species, but acute in H. trifurcata .

Adult ( Figs 4 A– 4I). Body and forewings mostly brown in alcohol. Forewings each 8.1–9.0 mm long in male (n = 5), 8.5 mm long in female (n = 1). Venation typical for the genus. Abdominal sternite V with pair of long finger-like processes near anterolateral margins.

Male genitalia ( Figs 4 B–4F). Anterior margin of sternite IX smoothly triangular in lateral aspect; tergite IX semi-sclerotized, mostly fused with segment X. Segment X large, semi-sclerotized dorsally, sclerotized laterally, membranous posteroventrally; spine-like process arising from posterolateral margins, directed dorsad. Inferior appendages long, 1-segmented, extending far beyond apex of segment X, apex with short spine-like setae mesally; in lateral aspect club-shaped, with subapex curved slightly upwards; in dorsal and ventral aspects slightly arched with apices pointed to each other. Phallic apparatus large, complex: Phallotheca (pha.) somewhat conical with pairs of dorsal processes (d.p.p.) and lateral processes (l.p.p); dorsal processes about 2/3 length of lateral ones, in lateral aspect arched, each apex with spine surrounded by hair, in dorsal aspect each constricted laterally at midway, forming square shoulder; lateral processes straight, each with subapex slightly bulged and then narrowed into point, with hair apicodorsally. Aedeagus (ae.) and two pairs of processes arising from endotheca (end.); aedeagus long, slightly shorter than lateral processes of phallotheca, with subapex narrower; dorsolateral processes of aedeagus (d.p.a.) in lateral aspect each thick and horn-like, with apex directed dorsad, in dorsal aspect each arched, with apices pointed to each other, each apex with single spine surrounded by hair; pair of ventral process of aedeagus (v.p.a.) slender, arising from aedeagus basolaterally, directed posteroventrad, shorter than aedeagus, with single spine surrounded by hair apically.

Female genitalia ( Figs 4 G– 4I). Sternite VIII cleft about half distance from base, forming pair of lateral lobes in ventral aspect, posterodorsal corner of each lobe round in lateral aspect. Segment IX triangular in dorsal aspect, oblique S-shaped in lateral aspect, each ventral margin protruding anteriorly. Segment X narrow rectangular in lateral aspect. Vulvar scale large, with X-shaped marking in ventral aspect.

Holotype. Male, Yaku-shima: Shiratani-unsui-kyo, Yaku-cho, (30.3794°N, 130.574°3E, 620 m a.s.l.), 12.vii.1992, T. Ogata ( CBM-ZI 166070 ).

Paratype. 3 males, same data as holotype ( CBM-ZI 166071–166073 ) .

Other specimens examined. Yaku-shima: 1 female, same data as holotype ; 1 male, Ara-kawa, Yakusugi-land, 30.304°N, 130.509°E, 12.v.2006, TI, S .

Etymology. The species name (Latin adjective) refers to the thick horn-like processes of the phallic apparatus.

Distribution. Japan: Ryukyu (Yaku-shima). Endemic to northern Ryukyu.

Japanese name. Tsuno-nisemiyama-shima-tobikera.

Remarks. Several additional unnamed Homoplectra species have been recorded from Japanese Islands including this species ( Nozaki 2018). Homology of the phallic structure in Japanese and North American Homoplectra spp. is not yet clear, but processes numbered (1) to (3) and (5) by Ross (1938) probably correspond to the pairs of dorsal processes and lateral processes of the phallotheca, and the pairs of dorsolateral processes and ventral processes of the aedeagus as they are named in this study, respectively. Ross (1938) numbered and described the aedeagus as “(4) rod-like apex of the aedeagus proper”.

Figures

FIGURE 4. Homoplectra crassicornea Nozaki & Ito sp. nov. and H. trifurcata Nozaki & Ito sp. nov. Homoplectra crassicornea (4A–4I): male (4A–4F): 4A, right wings, dorsal; 4B, genitalia, left lateral; 4C, same, dorsal; 4D, same, ventral; 4E, phallic apparatus, left lateral; 4F, same, dorsal; female (4G–4I): 4G, genitalia, left lateral; 4H, same, dorsal; 4I, same, ventral. Homoplectra trifurcata (4J–4Q): male (4J–4N): 4J, genitalia, left lateral; 4K, same, dorsal; 4L, same, ventral; 4M, phallic apparatus, left lateral; 4N, same, dorsal; female (4O–4Q): 4O, genitalia, left lateral; 4P, same, dorsal; 4Q, same, ventral. Abbreviations: I–V = apical forks I–V; VIII–X = abdominal segments VIII–X; sIX = sternite IX; ae. = aedeagus; d.p.a. = dorsolateral process of aedeagus (paired); d.p.p. = dorsal process of phallotheca (paired); end. = endotheca; l.p.p. = lateral process of phallotheca (paired); pha, phallotheca; v.p.a. = ventral process of aedeagus (paired).