Rhyacophila dentalis, Sun, Changhai, 2016

Sun, Changhai, 2016, Notes on the Rhyacophila angulata Species Group with descriptions of two new species (Insecta, Trichoptera, Rhyacophilidae), Zootaxa 4150 (2), pp. 193-200 : 196

Rhyacophila dentalis n. sp.

( Figs 3 , 4 A–4G)

Diagnosis. This new species is similar to R. longistyla Sun & Yang 1995 in male genitalia, but can be easily diagnosed by (1) the anterior margin of segment IX in lateral view being sinuate (straight in R. longistyla ); (2) the apicolateral teeth of the apicodorsal lobe of segment IX being absent (present in R. longistyla ); and (3) the basal segment of each inferior appendage in lateral view having a blunt tooth on the upper margin (in R. longistyla the upper margin is indented at the base).

Description. Length of each forewing of male 6.0–7.0 mm (n = 6), of female 7.0–8.0 mm (n = 6); length of body of male 5.0– 5.5 mm (n = 6), of female 6.0‒ 7.5 mm (n = 6). Body (in alcohol) yellowish brown. Head yellow, eyes black, antennae and palpi yellow. Prothorax brown; pterothorax dark brown dorsally, yellow laterally and ventrally; legs yellow, with brown spurs; forewings pale brown, with irregular dark brown patches ( Fig. 3 ), hind wings light brown. Abdomen dark brown dorsally and yellowish brown ventrally.

Male genitalia ( Fig. 4 ): Segment IX (IX) with ventral margin about one-fifth as long as its dorsal margin, its anterior margins in lateral view sinuate, its posterior margins under apicodorsal lobe slightly concave; in dorsal view its anterior margin slightly emarginated mesally, each lateral margin constricted at midlength, apicodorsal lobe (ad.l.) deeply incised apicomesally ( Fig. 4 B). Segment X (X) flattened, in lateral view oblique, narrow, barlike, and sinuous, in caudal view broad with apex incised mesally ( Fig. 4 D). Anal sclerites (as.) rounded. Phallotheca (pht.) subrectangular in lateral view and trapezoidal in ventral view. Aedeagus (aed.) tubular, slender, tapering from base to apex, in lateral view with apex curved slightly upwards. Parameres (par.) about 1.5 times as long as aedeagus, each tubular in basal two-thirds, but distal one-third somewhat dilated and then tapering to upturned apex; in dorsal view parameres crossing each other under aedeagus, with row of fine teeth along inner margin of dilated portion, its apex acute and curved mesad ( Fig. 4 F, 4G). Basal segment of each inferior appendage (bia.) subrectangular in lateral view, with basal margin slightly broader than truncate apical margin and upper margin with strong tooth; in ventral view slender, with base broader and apex obliquely truncate. Each apical segment (aia.) two-thirds as long as basal segment, with its base much narrower than apex of its basal segment; bifurcate at midlength with upper branch one-third as long as lower branch.

Holotype male. CHINA: Guang-xi Province , Nan-dan County, Qing-shui-he River at swinging bridge, Provincial Road 317 at marker 24.0 km, 24.901°N, 107.438°E, elev . 310 m, 14 June 2004, collected by Changhai SUN. Paratypes. Same collection data as holotype—3 males, 15 females; same collection data as holotype except for Provincial Road 317 at marker 22.0 km, 24.899°N, 107.422°E, elev. 438 m, 14 June 2004, collected by Xin ZHOU, Christy J. GERACI, and Karl M. KJER— 6 males, 9 females .

Etymology. The new species is named Rhyacophila dentalis n. sp. from the Latin word “ dentalis ,” meaning “having teeth,” referring to the tooth on the upper margin of the basal segment of each inferior appendage.

Distribution. China (Guang-xi).

Figures

FIGURE 3. Forewing of Rhyacophila dentalis n. sp. Scale bar: 1.0 mm.

FIGURE 4. Male genitalia of Rhyacophila dentalis n. sp. 4 A, left lateral; 4 B, segment IX, dorsal; 4 C, ventral; 4 D, segment X and anal sclerites, caudal; 4 E, left inferior appendage, left lateral; 4 F, phallic apparatus, dorsal; 4 G, distal one-third of left paramere, dorsal. Scale bars: 4 A – 4 F = 0.5 mm; 4 G = 0.25 mm. Abbreviations: ad. l. = apicodorsal lobe of segment IX; aed. = aedeagus; aia. = apical segment of one of a pair of inferior appendages; as. = anal sclerites; bia. = basal segment of one of a pair of inferior appendages; end. = endotheca; IX = segment IX; par. = parameres; pht. = phallotheca; tb. = tergal band; X = segment X.