Homoplectra crassa, 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 : 330-333

Homoplectra crassa sp. nov.

( Figs. 1 , 7 , 9 )

Diplectrona sp. 3: Torii & Hattori 2006, 38.

Homoplectra sp.: Katsuma 2012, 53.

Homoplectra sp.: Tsuruda 2018, 27, 31.

Diagnosis. Males of this species and Homoplectra ise sp. nov. are unique among known Homoplectra species in having two pairs of posterior processes on segment X. These two males can be easily distinguished from each other by the shape of the ventral process of the aedeagus: thick in this species, but slender in H. ise . The female of H. crassa sp. nov. is distinguished from other Japanese species by the following characters: the posteroventral margin of segment IX is oblique, and the darkly pigmented sclerite of the vaginal chamber is visible in lateral aspect.

Adult. Head and thorax dark brown dorsally with pale setal warts. Abdomen dark brown dorsally, legs brown. Antennae yellowish brown, slightly shorter than forewings. Forewings each 7.5–8.5 mm long in male (n = 10), 8.0– 10 mm long in female (n = 10); mostly dark brown with sparse pale spots. Venation as in Figures 1C , but occasionally cross vein m-cu close to cu1-cu 2 in forewings. Tibial spurs 2-4-4. Abdominal sternum V with pair of finger-like processes associated with scent glands near anterolateral margins, more than half as long as sternum in male, less than half as long as sternum in female; apices of these finger-like processes small globular.

Male genitalia. Sternum IX (sIX) with round anterior projection in lateral aspect; posteroventral lobe (p.l.) setose, trapezoidal in ventral aspect, with shallow median concavity. Tergum IX (t.IX) round posteriorly in dorsal aspect, fused with segment X (X) laterally. Segment X large, bilobed in dorsal aspect, membranous posteroventrally; two pairs of posterior processes (p.p.) strongly sclerotized, each apex with stout spine surrounded by hair. Inferior appendages (i.f.) without distal segment, extending beyond apex of segment X; each apex obliquely truncate in lateral and ventral aspects, with short spine-like setae mesally. Phallic apparatus thick, pair of dorsal processes of phallotheca (d.p.p.) long triangular in lateral aspect, short forceps-like in dorsal aspect, dorsomesal margin serrate; pair of lateral processes of phallotheca (l.p.p.) longer than dorsal processes of phallotheca, slightly curved downward, each having apex with single spine surrounded by hair. Aedeagus (ae.) with short head and with small ventral unpigmented bulge near head; pair of lateral processes of aedeagus (l.p.a) longer than aedeagus, twisted near base, each having apex with single spine surrounded by hair; ventral process of aedeagus (v.p.a.) thick, slightly longer than lateral processes of aedeagus, boat-shaped in lateral aspect, apex heart-shaped in dorsal aspect, with tiny setae apicodorsally.

Geographic variations in male genitalia. Males collected from Kawasaki-shi, Kanagawa Prefecture have the same genitalic characters as those collected from the type locality, but other males are variable in the shape and/or length of the posteroventral lobe of segment IX, the posterior processes of segment X, and the phallic processes (e.g., Figs. 1 J–1N).

Female genitalia. Sternite VIII cleft from base, forming pair of lateral lobes (l.l.) widely separated from each other posteriorly in ventral aspect; mesal margins of lateral lobes not fused with segment VIII. Segment IX (IX) triangular in dorsal aspect, obliquely S-shaped in lateral aspect. Segment X (X) rectangular in lateral aspect; each ventrolateral margin round in lateral aspect, darkly pigmented. Vulvar scale (v.s.) large, posterior part membranous; vaginal chamber (v.c.) sclerotized posterodorsally, pair of lateral darkly pigmented sclerites visible in lateral and ventral aspects. Vaginal apparatus (v.a.) pentagonal in ventral aspect, with long triangular projection anteriorly; in females from Hayakawa-cho, Yamanashi, middle part slightly narrower in ventral aspect, with longer anterior projection ( Fig. 1R ).

Final instar larva. Length up to 13 mm. Head 1.6–1.8 mm wide (n = 10), approximately same length as width, dark brown; frontoclypeal apotome broadly pyriform in dorsal aspect, with rounded constrictions around eyes and broad angles posterior of eyes, anterior margin slightly concave in middle; secondary setae usually acicular ( Fig. 7C ), but clavate ( Fig. 7D ) in 7 of 20 larvae collected from type locality and all larvae collected from Sakai-gawa, Kanagawa Prefecture. Mandibles each with stout basodorsal flange laterally, with 5 teeth. Pronotum with transverse sulcus on posterior 1/4. Thoracic nota with normal setae, but larvae collected from Sakai-gawa, Kanagawa Prefecture with clavate secondary setae. Middle femora, tibiae, and tarsi, and hind femora and tibiae with pinnate setae mesoventrally. Meso- and metathorax and abdominal segments bearing gills, with one pair of ventral tufts of gills on mesothorax and abdominal segment VII, with two pairs of ventral tufts of gills on metathorax and each of abdominal segments I to VI, with 1–3 lateral conical gills on each of abdominal segments III to VII.

Pupa. Length 8–9 mm (n = 2). Mandibles slender, with 3 (right) or 4 (left) apical and subapical teeth, each mandible with stout mesal plate-like projection on apical 1/3. Middle tarsi bearing sparse hair-like setae. Abdominal segments with dorsal hook plates anteriorly on II to VIII, posteriorly on III and IV. Abdominal segments bearing gills, with one pair of ventral tufts of gills on each of abdominal segments II to VII, with 1–3 lateral conical gills on each of abdominal segments III to VII. Anal processes strongly sclerotized, bifurcated, concave ventral surfaces covered by tiny spines.

Holotype. Male (pinned): Mogusa-yama-ryokuchi, Misawa, Hino-shi , Tokyo, 35.6564°N, 139.4256°E, alt. 76 m, 16.vi.2017, T. Nozaki ( CBM-ZI 0167047 ).

Paratypes. 3 males (pinned), same data as holotype ( CBM-ZI 0167048–0167050 ) ; 4 males, 2 females (in alcohol), type locality, 3.ix.2005, D. Tsuruda ( CBM-ZI 0167051–0167056 ) .

Other specimens examined. Ibaraki: 1 male, Hatori, Sakuragawa-shi , 7.vii.2011, H. Sakurai (NoK) . Tokyo: 2 males, 1 female, 2 larvae, 1 pupa, same data as holotype ; 1 male, type locality, 3.vii.2005, D. Tsuruda; 1 larva, type locality, 10.vi.2006, D. Tsuruda; 1 male, 1 female, 17 larvae, type locality, 14.vi.2018, T. Nozaki (9 larvae: CBM) ; 2 males, Tama-gawa, Okutama-machi , 4.vii.1987, N. Gyotoku . Kanagawa: 1 larva, Ikuta-ryokuchi, Tama-ku, Kawasaki-shi , 29.vi.1986, T. Nozaki ; 2 males, 1 female, 2 pupal exuviae, same collection data, pupae collected on 29.vi.1986, adults emerged on 18–28.vii.1986, by T. Nozaki ; 7 larvae, Sakai-gawa, Shiroyama, Midori-ku , Sagamihara-shi , 24.iv.1984, T. Nozaki ; 4 females, 4 pupal exuviae, same collection data, larvae collected on 24.iv.1984, adults emerged on 13.vi.1984 – 1.viii.1984 ; 1 pupa, same locality, 23.vii.1984, M. Tokuda ; 2 males, same locality, 9–10.viii.1984, T. Nozaki ; 7 larvae, same locality, 10.viii.1984, T. Nozaki ; 1 female, same locality, 6.ix.1984, T. Nozaki, 1984 ; 1 female, Matsutake-yama, Toya, Midori-ku , Sagamihara , 24.vii.2011, T. Nozaki; 1 larva, Morito-gawa, Sakurayama , Zushi-shi , 15.iii.2009, T. Nozaki ; 5 larvae, same locality, 11.v.1998, T. Nozaki ; 6 larvae, Nobi, Yokosuka-shi , 7.iv.1988, T. Nozaki ; 2 males, same locality, 15.vii.1989, T. Nozaki . Yamanashi: 1 male, 1 female, small stream, Akasawa, Hayakawa-cho , 3.viii.2008, T. Nozaki ; 1 male, 3 females, seep, alt. 500 m, Akasawa, Hayakawa-cho , 23–24.viii.2009, T. Nozaki & T. Hattori . Nagano: 1 male, Tanasawa-gawa, alt. 980 m, Tera, Ina-shi , 21.vi.2003, T. Nozaki ; 4 males, Toyohira, Chino-shi , 25.vii.2012, N. Katsuma (NoK) . Shizuoka: 1 male, 1 larva, Utoge-no-taki, Setonoya, Fujieda-shi , 4.viii.2004 ( TT) ; 1 male, 1 larva, Yamame-dani, Setonoya, Fujieda-shi , 1.vii.2007 ( TT) . Aichi: 2 males, Takadoya-shicchi, Otagi-cho, Toyota-shi , 27.vii.2012, H. Nishimoto .

Etymology. The specific epithet (Latin adjective, “thick”) refers to the thick ventral process of the aedeagus.

Distribution. Honshu (central).

Biology. Larvae of this species were collected from seeps in hill or mountain areas. The adult flight season is June to October at the type locality ( Tsuruda 2018).

Japanese name. Futoo-nisemiyama-shima-tobikera.

Remarks. Immature stages of this species and another Japanese species, H. tohokuensis , are similar to those of North American species described by Weaver et al. (1979), Huryn (1989), and Wiggins (1996). The larva of this species can be distinguished from that of H. tohokuensis by the shape of the anterior margin of the frontoclypeal apotome: Slightly concave in this species, but slightly convex in H. tohokuensis .

Figures

FIGURE 1. Adults of Homoplectra crassa sp nov. 1A, male habitus, left lateral; 1B, male head and pro- and mesonota, dorsal; 1C, male right wings, dorsal; 1D, male sternum V, left lateral. 1E–1I, male genitalia, type locality (Tokyo, Hino-shi): 1E, left lateral, apicomesal part enlarged; 1F, dorsal; 1G, ventral; 1H, phallic apparatus, left lateral; 1I, same, dorsal, mesal margin of left dorsal process of phallotheca enlarged. 1J–1N, male genitalia, variations: 1J1, ventral lobe of segment IX, ventral, Kanagawa (Yokosuka-shi); 1J2, same, Nagano (Chino-shi); 1K1, segment X, left lateral, Kanagawa (Yokosuka-shi); 1K2, same, Shizuoka (Fujieda-shi); 1L, phallic apparatus, left lateral, Shizuoka (Fujieda-shi); 1M1, phallotheca, dorsal, Shizuoka (Fujieda-shi); 1M2, dorsal process of phallotheca, dorsal, Kanagawa (Yokosuka-shi); 1N1, aedeagus, dorsal, Shizuoka (Fujieda-shi); 1N2, same, Kanagawa (Yokosuka-shi); 1N3, same, Nagano (Chino-shi). 1O–1Q, female genitalia, type locality except as indicated: 1O, left lateral; 1P, dorsal; 1Q, ventral. 1R, female vaginal sclerite, ventral, Yamanashi (Hayakawa-machi). Abbreviations: ae. = aedeagus, d.p.p. = dorsal process of phallotheca (paired), end. = endotheca, i. a. = inferior appendage (paired), IX = abdominal segment IX, l.l. = lateral lobe of sternum VIII (paired), l.p.a = lateral process of aedeagus (paired), l.p.p, = lateral process of phallotheca (paired), p.l. = posteroventral lobe of sternum IX, ph. = phallotheca, p.p. = posterior process of segment X (paired), sIX = sternum IX, tIX = tergum IX, v.a. = vaginal apparatus; v.c. = vaginal chamber, v.s. = vulval scale, v.p.a. = ventral process of aedeagus, X = abdominal segment X.

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

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.