Rivula medogensis, Jin & Han, 2025

Rivula medogensis sp. nov.

(Chinese name: ḆṈ涓njď)

urn:lsid:zoobank.org:act:575E22FB-DA3F-453B-ABB8-F8772A8DF616

Figures 1, 2, 10, 12

Type material. Holotype. male, China, Aut. Reg. Xizang, Linzhi City, Medog County, Beibeng Countryside, Dergong Village , 26 May–4 Jun. 2021, leg. HL. Han, genit. prep. JYY-216-1, coll. NEFU . Paratypes. 3 males, 2 females, same data as for holotype, genit. prep. JYY-136-1, JYY-138-1, JYY-217-1, JYY-139-2 and JYY-137-2, coll. NEFU ; 2 males, China, Aut. Reg. Xizang, Linzhi City, Medog County, Gedang Township , 25–30 May. 2021, leg. J. Wu, JJ. Fan, genit. prep. JYY-240-1, JYY-241-1, coll. NEFU .

Diagnosis. This new species is similar to R. niveipuncta Swinhoe, 1905 (Figs. 3, 11, 13), but it can be distinguished by the following morphological characters (characters for R. niveipuncta are in parentheses):

Adult of R. medogensis sp. nov. (Figs. 1, 2) has a strip-like white mark on the forewing, which is surrounded by black ( niveipuncta with white and large round spots); the basal spots are degenerated, and the subbasal spots are crossed by droplet-shaped markings (small white dots, with subbasal spots irregularly rounded in niveipuncta ); the antemedial and postmedial lines are formed by a white long band and short spots (formed by small and white dots in niveipuncta ).

In the male genitalia of R. medogensis sp. nov. (Fig. 10), the cucullus is band-shaped and blunt on the apex (tapering towards the apex in niveipuncta ); juxta with monk hat shape on top (with two blade-shape on top in niveipuncta ); valva is broad and with a triangular clasper (narrow and without clasper in niveipuncta ). Aedeagus is weakly curved (straight in niveipuncta ).

In the female genitalia of R. medogensis sp. nov. (Fig. 12), the papillae analis is narrow (broad in niveipuncta ); the ostium bursae is band-shaped (triangle-shaped in niveipuncta ); the ductus bursae is broad and shorter than 1/2 the corpus bursae (slender in niveipuncta and approximately 2/3 as long as the corpus bursae); the posterior section of the corpus bursae is broad (slender in niveipuncta ); the signa is thin, sclerotized, and broad (strongly sclerotized and narrower in niveipuncta ).

Description. Adult (Figs. 1, 2). Wingspan 19–20 mm. Head ochre, with a little yellow; labial palpus yellowish brown and extending forward beyond the front; antenna yellowish brown and filiform in both sexes. Thorax darker reddish brown; patagium and tegula lighter. Forewing light ochre to reddish brown; costal margin area darker than ground color, diffused black; basal line formed by 4 white bands or dots, among them the 3rd band long, longitudinal and extending to antemedial line; antemedial line bent in an M-shaped and formed by white dots or stripes of varying sizes, surrounded by black; medial line absent; postmedial line approximately the same as antemedial line, but behind Cu 2; subterminal line with a large and white dot on costal margin, other very small and indistinct, surrounded entirely by black; fringe slightly darker than ground color; orbicular spot indistinct; reniform spot formed by 4–6 white spots of varying size. Hindwing lighter than forewing; discal spot absent; vein indistinct; fringe more reddish brown on outer margin, but with grayish white on inner margin.

Male genitalia (Fig. 10). Uncus strongly sclerotized, hook-shaped, basal part bifurcate, rather blunt on the apex. Tegumen broad and strongly sclerotized, about 1.5 times longer than uncus. Vinculum slender, strongly sclerotized, and broadly U-shaped. Juxta tongue-shaped, with monk hat shape on top. Valva more membranous, bar-shaped and with densely covered small grain; costa thin and broader than sacculus; and slightly extend to cucullus; thick, weakly sclerotized, and incurved; claspex half spiral, triangular, weakly sclerotized at basal part of sacculus; cucullus membranous, narrow, and bar-shaped, with blunt apex. Aedeagus tube-shaped, strongly sclerotized, and with slight curve at the dorsal of the ductus ejaculatorius; cecum 1/3 times longer than aedeagus. Vesica membranous, with 2 subbasal diverticula; and 5 median diverticula, densely covered by small grains.

Female genitalia (Fig. 12). Papillae anales narrow and taper-shaped. Apophysis posterioris and apophysis anterioris slender, anterioris 3/5 times longer than posterioris. The 7th segment weakly sclerotized. Ostium bursae straight and band-shaped. Ductus bursae membranous, with longitudinal folds, about 5/12 as long as corpus bursae. Corpus bursae long; posterior section of corpus bursae broad and cylinder-shaped, with longitudinal folds, and with ductus seminalis at the terminal part; anterior section of corpus bursae long and oval-shaped, with 3 weakly sclerotized signa plates, and with parallel and horizontal ridges on every plate.

Bionomics. The species was collected between May and June at altitudes ranging from 1850 to 1985 m. The collection site, located adjacent to a subtropical evergreen broad-leaved forest, transitions into a mixed coniferous and broadleaf forest as altitude increases. The forest floor is densely populated with abundant shrubs, ferns, and patches of grassland (Figs. 18, 19).

Distribution. China (Xizang).

Etymology. This species name is derived from the locality of the type, Medog (Motuo).