Stactobiella amami, Ito, 2020

Ito, Tomiko, 2020, The genus Stactobiella Martynov (Trichoptera, Hydroptilidae) in Japan, Zootaxa 4748 (3), pp. 561-571 : 567

Stactobiella amami sp. nov. ( Figs 4 , 6 )

Diagnosis. The male of this species is somewhat similar to those of Stactobiella parallelica Zhou et al. 2016 and S. mutica Zhou et al. 2016 , described from south-eastern China, in having widely curved inferior appendages, but is clearly distinguished from the latter by presence of long ventro-lateral appendages.

Adult. In males, wings and antennae brown; forewings each 1.5 mm long and hind wings each 1.2–1.3 mm long (n=3); antennae each 18-segmented, 0.6 mm long (n=1). Males with short ventral process on abdominal segment VII.

Male ( Fig. 4 ). Segment IX shorter than segment VIII, with pair of long anterior apodemes; with lateral processes posteriorly and rounded ventral sclerite postero-mesally. Segment X membranous, subrectangular. Subgenital plate heavily sclerotized, thick, strongly curved ventrad. Ventro-lateral appendages directed dorso-posterad basally, gently curved ventro-mesad at proximal 2/3, acute apically in lateral view; in ventral and dorsal views, almost semicircular in shape with broad middle parts and acute apices. Inferior appendages plate-like, each with ventral quadrate lobe in ventral view, broadly bar-shaped in lateral view; few long and many short setae marginally. Aedeagus almost straight, gradually tapered distally, tiny cleft apically.

Female. Unknown.

Holotype. Male , Japan, Ryukyu : Amami-o-shima, Uken-son, Kawauchi-gawa, middle reach (28.2667 N, 129.3500 E, 90 m above sea level.), 20.x.2014, T. Ito, light pan trap (CBM-ZI 0178574).

Paratypes. 1 male, same data as holotype (CBM-ZI 0178575) .

Other specimens. Amami-oshima: 1 male, Yamato-son, Materia-gawa, upper reach, 21.x.2014, T. Ito, light trap .

Distribution ( Fig. 6 ). Japan (Ryukyu: Amami-o-shima).

Habitat. Adults of this species were collected near rapid streams with large rocks.

Etymology. The name “ amami ” is a noun in apposition, coined from the type locality.

Japanese name. Amami-sawa-himetobikera.

Figures

FIGURE 4. Stactobiella amami sp. nov., male. 4A, genitalia, left lateral; 4B, same, dorsal; 4C, same, ventral. Abbreviations: VII–X=abdominal segments VII–X; ae=aedeagus; ia=inferior appendage (paired); lp=lateral process (paired); sp=subgenital plate; vla=ventro-lateral appendage (paired); vs=ventral sclerite. Scale bar, 0.1 mm.

FIGURE 6. Distributions of five species of the genus Stactobiella in Japan and neighboring countries. Symbols in Russia, Mongolia and China are cited from references.