Homoplectra tohokuensis ( Kobayashi 1973 )

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 : 336-338

Homoplectra tohokuensis ( Kobayashi 1973)

( Figs. 4 , 8 , 9 )

Diplectrona tohokuensis Kobayashi 1973 , 31–32, pl. 7, male. New combination.

Diagnosis. The male and female of this species are somewhat similar to those of H. occidens sp. nov., but can be distinguished by the characters given in the diagnosis for that species, below.

Adult. Mostly dark brown, but femora, tibiae and tarsi of all legs light brown. Forewings each 6.2–8.4 mm long in male (n = 8), 7.5–9.5 mm in female (n = 3). Venation similar to that of H. crassa sp. nov. Abdominal sternum V with pair of finger-like processes, more than half as long as sternum in male, approximately half length of sternum in female, each with apex narrowed.

Male genitalia. Sternum IX protruding anteriorly, with round apex on each side in lateral aspect; short posteroventral lobe semicircular in ventral aspect, but often trapezoidal. Tergum IX broadly fused with segment X. Segment X large, bilobed in dorsal aspect, unpigmented dorsomesally, setose laterally, membranous posteroventrally; each lobe with acute posterior process curved dorsad. Inferior appendages long, 1-segmented, each with apical 1/4 slightly curved upward, apex blunt with short spine-like setae ventromesally. Phallic apparatus arcuate in lateral aspect, phallotheca with pair of slender, straight, acute dorsal processes; with pair of lateral, acute processes slightly shorter than dorsal processes, curved slightly ventrad apically. Aedeagus slender, fingertip-like head long, approximately 1/3 as long as basal stem, apex curved slightly upward; pair of fin-like lateral processes fused with aedeagus in their basal 2/3; needle-like process arising from base of each fin-like process, each with apex extending slightly beyond apex of its lateral fin-like process.

Female genitalia. Lateral lobes of sternite VIII fused with segment VIII about 1/3 distance from base, smoothly triangular in ventral aspect. Segment IX obliquely S-shaped in lateral aspect, mucronate posteromesally in dorsal aspect. Vulval scale large, with round semimembranous apex in ventral aspect. Vaginal apparatus long oval in ventral aspect, anterior finger-like part protruding into segment VII.

Larva. Length up to 12 mm. Head 1.6 mm wide (n = 3). Very similar to H. crassa , but anterior margin of frontoclypeal apotome slightly convex.

Pupa. Only one set of pupal exuviae available for this study. Indistinguishable from H. crassa sp. nov.

Specimens examined. Holotype, male, Minoyama, Hirata-machi, Akumi-gun , Yamagata, 21.v.1970, K. Shirahata ( CBM: M2565 ). HONSHU. Aomori: 2 males, 1 female, brooklet, Sasanai-gawa , Iwasaki , Fukaura-machi , 17.vii.2004, N. Kuhara. Iwate: 2 males, Hiraniwa-kogen , Yamagata-cho , Kuji-shi , 12.vii.1997, N. Kuhara (KuN); 1 male, Kassenba , Yamagata-cho , Kuji-shi , 19.vii.2004, N. Kuhara (KuN); 6 males, brooklet beside Iwaigawa , alt. 178 m, Kuji-shi, 12.vi.2004, N. Kuhara (KuN); 2 males, head of Mitakai-gawa, alt. 750 m, Iwaizumicho, 19.vii.2004, N. Kuhara (KuN); 1 male, brooklet nr. Hayasaka-toge, alt. 820 m, Iwaizumi-cho, 18.vii.2004, N. Kuhara (KuN); 1 male, Mitaki, Koromogawaku-nagafukuro, Oshu-shi, 19.iv.2017, T. Ito; 1 male, Misawa-gawa, Koromogawaku-omori, Oshu-shi, 19–20.vi.2017, T. Ito; 1 male, 1 female, Yagosawa, Oshu-shi, 14.vii.2012, M. Tanaka. Miyagi: 8 males, 2 females, Onamezawa, Natori-gawa, Sendai-shi, 1.vi.1994, T. Ito; 3 males, Futakuchi, Sendai-shi, 10.v.1997, T. Ito (KuN). Akita: 1 male, Ainono, Sannai, Yokote-shi, 18.vi.2011, M. Tanaka ( MT); 1 male, Kubo, Sannai, Yokote-shi, 18.vi.2011, M. Tanaka ( MT); 1 male, Takinoshita, Masuda, Yokote-shi, 15.vi.2011, M. Tanaka ( MT); 1 male, Mt. Mitake , Yokote, Yokote-shi, 1.viii.2011, M. Tanaka ( MT); 1 male, Yubichi-zawa, Tazawa-ko, Senboku-shi, 24.ix.2013, M. Tanaka ( MT); 1 male, Mt. Ohikage , Oodate, Oodate-shi, 15.vi.2008, M. Tanaka; 1 male, Kitanomata-zawa, Higashinaruse-mura, 10.ix.2013, M. Tanaka; 1 male, Kotaki-zawa, Nakasen, Daisen-shi, 13.vii.2008, M. Tanaka; 1 male, 1 female, Nibetsu, Akita-shi, 24.v.2017; M. Tanaka. Yamagata: 1 larva, 2 prepupae, seep, near headwater of Ara-kawa River , Oguni-machi, 1.vi.1986, T. Nozaki; 1 male, same locality., pupa collected on 1.vi.1986, adult emerged on 16.vi.1986 by T. Nozaki; 2 males, 1 female, Ooisawa, Nishikawamachi, 24.v.1998, T. Nozaki; 1 male, same data except collector A. Ohkawa ( TT); 4 males, Hirano, Nagai-shi, 6.vi.2013, N. Katsuma (NoK).

Etymology. This species was named from the Tohoku district, northeastern Honshu.

Distribution. Honshu (northeast).

Habitat. Larvae of this species were collected from a seep where water flows through cracks of vertical rock faces in a mountain area.

Japanese name. Tohoku-miyama-shima-tobikera

Remarks. Kobayashi (1973) described this species as a member of the genus Diplectrona Westwood 1839 (1838–1840). I examined the holotype male of this species deposited in CBM, and confirmed the general morphology. The short and wide postcostal cell of the forewing venation, the pair of finger-like processes of abdominal sternum V, and one-segmented inferior appendages are in common with Homoplectra species.

Figures

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

FIGURES 4–5. Adults of Homoplectra spp. 4A–4H, Homoplectra tohokuensis (Kobayashi 1973). 4A–4E, male genitalia: 4A, left lateral; 4B, dorsal; 4C, ventral; 4D, apical half of phallic apparatus, left lateral; 4E, same, dorsal. 4F–4H, female genitalia: 4F, left lateral, 4G, dorsal; 4H, ventral. 5A–5J, Homoplectra occidens sp. nov. 5A–5D, male genitalia, type locality: 5A, left lateral; 5B, dorsal; 5C, ventral; 5D, phallic apparatus, dorsal. 5E–5G, male genitalia, variations: 5E1, posteroventral lobe of abdominal segment IX, ventral, Shiga (Takashima-shi); 5E2, same, Okayama (Tsuyama-shi); 5F, apical half of phallic apparatus, left lateral, Shiga (Takashima-shi); 5G, apical part of aedeagus, ventral, Shiga (Takashima-shi). 5H–5J, female genitalia, type locality: 5H, left lateral; 5I, dorsal; 5J, ventral. Arrows see text.

FIGURES 7–8. Immature stages of Homoplectra spp. 7A–7R, Homoplectra crassa sp. nov. 7A–7L, larva: 7A, right lateral; 7B, head, pro-, meso-, and metanota, dorsal; 7C and 7D, setae on anterior margin of head, dorsal; 7E, head, ventral; 7F, left mandible, dorsal; 7G, right mandible, dorsal; 7H, right foreleg, posterior; 7I, right midleg, posterior; 7J, right midleg, anterior, seta near ventral margin enlarged; 7K, right hind leg, posterior; 7L, abdominal segments VIII and IX, ventral. 7M–7R, pupa: 7M, dorsal; 7N, left mandible, dorsal; 7O, right mandible, dorsal; 7P, right midleg, posterior; 7Q, dorsal hook plates, dorsal; 7R, segment IX and anal processes, ventral. 8, Homoplectra tohokuensis (Kobayashi 1973), larval head, dorsal. Abbreviations: a = anterior; p = posterior; II–IX = abdominal segments II–IX.