Lepidostoma yuwanense, Ito, Tomiko, 2016

Ito, Tomiko, 2016, The Lepidostoma coreanum Species Complex (Trichoptera, Lepidostomatidae) in the Asian Far East, Zootaxa 4061 (4), pp. 397-417 : 412-414

Lepidostoma yuwanense sp. nov.

( Figs. 18–19 , 21 )

Diagnosis. Males of this species are similar to those of Lepidostoma coreanum ( Kumanski & Weaver 1992) , but are clearly discriminated from the later by the ventral view of the main articles of the inferior appendages: subquadrate with small rectangle projections on latero-caudal corners in this species ( Fig. 18 G), but semicircular without any latero-caudal projections in L. coreanum ( Fig. 1 G). Females of this species are also similar to those of L. coreanum and difficult to discriminate from each other.

Male ( Figs. 18–19 ). Type specimens ( Fig. 18 ). Antennae about 5.5–6.0 mm long, each with scape setose, thick and long, about 1.5 times as long as head, with short mesal process near mid length. Maxillary palps extremely setose, each 2-segmented, 0.8 mm long in total, basal segment curved anterad in basal half, with tuft of very long setae apically, long apical segment emerging near middle of basal segment. Labial palps each 3-segmented, slender, 0.8 mm long in total.

Wings covered with fine setae and short scales; spindle-like setae lining Cu and encircling cubital area; forewings each with apical forks 1 and 2, discoidal cell and arculus, Cu1 and Cu2 complex in caudal area ( Fig. 18 C); hind wings each with apical fork 1, vein A absent; forewings and hind wings each 5.2–5.7 mm long and 4.5– 4.5 mm long, respectively (n=3).

Genitalia. Abdominal segment IX short, dorsum slightly longer than venter. Segment X composed of mesal, lateral and ventral arms; mesal arms long, curved slightly ventrad near base and directed caudad in apical 1/3, lateral arms directed caudad and shorter than mesal arms, ventral arms long, directed caudolaterad in dorsal view; 3 pairs of arms subacute apically. Inferior appendages each composed of main article, dorsal hook, and inner hook; basal half of main article broad in lateral view, subquadrate in ventral view with serrate posterior margin and small rectangle projections at posterolateral corner; apical half of main article curved mesad, comb-shaped in lateral view; dorsal hook bar-like with spiny apex, curved mesad in ventral view; inner hook much shorter than dorsal hook, bar-like, directed laterad in ventral view. Phallic apparatus thick, membranous in apical half with inner Ushaped sclerite, paramere absent.

Variation ( Fig. 19 ). The males collected from Okinawa-jima show some variations. The ventral arms of segment X are long, exceeding the tips of the mesal arms in lateral view. A short vein is present between C and Sc in each forewing, crossvein r-m present in each hind wing.

Female ( Fig. 18 H–J). Type specimens. Antennae about 6 mm long, each with scape thick, long and 2 times as long as head, mesal process absent. Maxillary palps each 5-segmented and about 0.7 mm long, labial palps each 3- segmented and 0.4 mm long, all palps slender.

Wings covered with short fine setae, venation typical of other species of Lepidostomatidae ; forewings and hind wings each 5.2–5.4 mm long and 4.5–4.8 mm long, respectively (n=2).

Lateral ends of tergite VIII broad. Lateral plates weakly sclerotized, subtriangular. Subgenital plate subquadrate slightly concave anterior margin and almost straight posterior margin with small shallow central notch. Vaginal apparatus oval and slightly sclerotized.

Immature stages. Unknown.

Holotype: Japan, Ryukyu Islands, Amami-Ooshima: 1 male, Uken-son, Yuwan, small water flow on trail to Mt. Yuwan-dake, 28˚17’22”N, 129˚17’31”E, 600 m, 9.vi.1996, T. Ito (CBM-ZI 151260).

Paratypes. 2 males, 2 females, same data as holotype (CBM-ZI 151261 – 151264).

Other specimens examined. Japan, Ryukyu Islands, Amami-Ooshima: 4 males, 3 females, same data as holotype. Okinawa-jima: 2 males, Nago-shi, Genka, hygropetric zone near Hogen-hashi, 22–24.xi.2010, T. Ito; 7 males, 2 females, same locality, 8.iv.2011, T. Ito; 1 male, same locality, 17–19.x.2014, T. Ito.

Etymology. The specific name refers to the name of the type locality.

Distribution ( Fig. 21 ). Japan (Ryukyu Islands: Amami-Ooshima, Okinawa-jima).

Habitat. Adults were collected from beside small water flows and hygropetric zones in forests.

Japanese name. Yuwan-sunatsutsu-tobikera.

Figures

FIGURE 1. Lepidostoma coreanum, male, specimens from Primorye. A, head, right scape and maxillary palp, right lateral; B, right scape, ventral; C, right forewing, dorsal; D, right hind wing, dorsal; E, genitalia, left lateral; F, same, dorsal; G, same, ventral. Abbreviations. Body: IX = abdominal segment IX, X = abdominal segment X; ma, la and va = mesal, lateral and ventral arms of segment X, respectively; ia = inferior appendage; ih, dh and maia = inner hook, dorsal hook and main article of an inferior appendage, respectively; ph = phallic apparatus. Wings: 1 – 2 = apical forks I and II; d = discoidal cell; th = thyridial cell; ar = arculus; C = costa; Sc = subcosta; R = radius; Ma = anterior media; Mp = posterior media; Cu = cubitus; A = anal vein.

FIGURE 18. Lepidostoma yuwanense, male and female, type specimens. A – G, Male: A, head, left scape and maxillary palp, left lateral; B, right scape, dorsal; C, right forewing, dorsal; D, right hind wing, dorsal; E, genitalia, left lateral; F, same, dorsal; G, same, ventral. H – J, Female: H, abdominal segments VII – X, left lateral; I, abdominal segments VIII – X, ventral, subgenital plate omitted; J, subgenital plate, ventral, posterior edge up. Abbreviations as in Figs. 1 and 6.

FIGURE 19. Lepidostoma yuwanense, male, variation, specimens from Okinawa-jima. A, head, left scape and maxillary palp, left lateral; B, right forewing, dorsal; C, right hind wing, dorsal; D, genitalia, left lateral; E, same, ventral.

FIGURE 21. Distribution of the 5 species of the Lepidostoma coreanum Species Complex of the genus Lepidostoma. The plot in North Korea was referred from Kumanski & Weaver (1992).