Rhyacophila bicaudata, Sun, 2016

Sun, Changhai, 2016, Two new species of the Rhyacophila anatina Species Group from China (Trichoptera: Rhyacophilidae), Zootaxa 4085 (2) : 276-277

Rhyacophila bicaudata n. sp.

( Fig. 2A–2D )

Male. Length of each forewing 7.0–9.0 mm. (n=3). Body (in alcohol) dark brown. Head dark brown, antennae brown with pale rings at basal and distal ends of each joint, palpi brown. Thorax dark brown dorsally, brown laterally and ventrally; wings brown; legs brown, with dark brown spurs. Abdomen black dorsally and yellowish brown ventrally.

Male genitalia. Segment IX in lateral view short ventrally, dorsal margin about 7 times as long as ventral margin, apicodorsal lobes about half as long as dorsal margin of basal segment of each inferior appendage; in dorsal view anterior margin broadly incised, apicodorsal lobe gradually tapered from base to shallowly incised apex. Preanal appendages about 1.5 times as long as apicodorsal lobe, somewhat triangular in lateral view with apices round; in dorsal view slender, each with lateral margin concave, apex acuminate. Segment X in lateral view vertical, dorsal and ventral ends curved cephalad. Anal sclerites in lateral view somewhat rectangular, oblique; in caudal view paired, each nephroid in shape. Basal segment of each inferior appendage long, in lateral view basal portion slightly thicker than distal portion, anterior margin oblique, posterior margin truncate; apical segment in lateral view triangular, about 1/2 as long as basal segment, gradually tapered from base to round apex. Phallic apparatus complex: Phallotheca in lateral view with basal half somewhat rectangular, distal half triangular; dorsal process elongate, heavily sclerotized, in dorsal view somewhat clavate, apex round; aedeagus tubular; parameres slender, each with distal end with strong bristles and spinules.

Female. Unknown.

Diagnosis. The new species resembles R. triangularis SCHMID 1970 in male genitalia, but can be distinguished in that (1) the preanal appendages are longer than the apicodorsal lobe (they are equal in length in R. triangularis ); (2) each preanal appendage has its posteroventral margin slightly concave (posteroventral margin straight in R. triangularis ); and (3) the apicodorsal lobe is gradually tapered from base to apex (it is gradually enlarged from base to apex in R. triangularis ).

Holotype Male. CHINA: Guang-dong Province, Zhao-qing City, Ding-hu District, Ding-hu-shan Forest Ecosystem, Research Station of Academia Sinica, Dong-gou at Shui-lian-dong-tian Waterfall, 23.1605°N, 112.5250°E, elev. 170 m, 24 May 2004, collected by Christy J. GERACI, John C. MORSE, SUN Chang-hai. Paratypes. Guang-dong Province, Ru-yuan County, Nan-ling National Nature Preserve, Lao-peng-keng at cascading tributary, Route X327, marker 22.5 km, 24.9343°N, 113.0095°E, elev. 1110 m, 18–19 May 2004, collected by John C. MORSE, TONG Xiao-li, ZHOU Xin, 1 male; Jiang-xi Province, Jiu-lian-shan National Nature Reserve, Da-qiu-tian scenic spot, 13.2 km NW of Jiu-lian-shan Nature Reserve, Xia-gong-tang Station, Mei-hualuo-di, main river, 24.5903°N, 114.4547°E, elev. 377 m, 10 Jun 2005, collected by YANG Lian-fang, 1 male.

Etymology. The species name comes from Latin prefix bi- meaning “two”, and Latin adjective caudatus meaning “having a tail,” thus bicaudata meaning “two-tailed,” in reference to the preanal appendages extending beyond the apicodorsal lobe, giving an appearance of two tails in dorsal view.

Distribution. CHINA (Guang-dong, Jiang-xi).

Figures

FIGURE 2. Rhyacophila bicaudata n. sp., male genitalia: 2 A, left lateral; 2 B, segment IX and preanal appendages, dorsal; 2 C, segment X and anal sclerites, caudal; 2 D, phallic apparatus, dorsal.