Mongoloniscus parvus Jiang, Li & Huang sp. nov.

Figs 4 E, F, 7

Type material.

Holotype. China: ♂ (20200913004), Liaoning Province, Huanren Manchu Autonomous County: Erpengdianzi Town, Yaoqianshu Village (41.1893 ° N, 125.6383 ° E), 610 m asl., 13. ix. 2020, coll. Chao Jiang.

Paratypes. 3 ♂♂, 2 ♀♀ (20200913003, 2020091300005), same data as the holotype; 3 ♂♂, 2 ♀♀ (20200906002 – 20200906005), Liaoning Province, Huanren Manchu Autonomous County, Erpengdianzi Town (41.236 ° N, 125.6047 ° E), 560 m asl., 6. ix. 2021, coll. Chao Jiang . 1 ♂, 2 ♀♀ (20200913001, 20200913002), Jilin Province, Ji’an, Xihulugou Village (41.3348 ° N, 125.8893 ° E), 670 m asl., 13. ix. 2020, coll. Chao Jiang .

Diagnosis.

Antennal flagellum distal article approximately twice as long as the proximal article. Pereopod 7 ischium sternal margin fringed with sparse setae; carpus slightly expands on tergal margin. Pleopod 1 exopod oval, distal apex slightly concave, forming two inconspicuous lobes, inner lobe bearing one seta.

Description.

Body length of males 5–9 mm and females 4–9 mm. Body elongated and convex, ~ 2.3 × as long as widest pereonite. Dorsum distinctly granulated, brown-gray color with usual yellowish muscle spots. Numerous gland pores along entire margin pereonites margin (Fig. 4 E, F). Pereonite 1 with rounded posterior margin and postero-lateral corners. Noduli laterales on pereonites 1–4 much farther from lateral margins than those on pereonites 5–7. Telson triangular, ~ 1.5 × as wide as long, lateral margins slightly concave near middle, posterior apex blunted; uropodal exopod 1.2–1.5 × as long as protopod; protopod with an incision on outer margin (Figs 3 F, 4 E, 7 B).

Cephalon with medial lobe arched, not surpassing lateral lobes in dorsal view. Eyes with 14 or 15 ommatidia. Antenna with fifth article of peduncle and flagellum nearly equal in length; flagellum with distal article twice as long as proximal one (Fig. 7 C).

Pereopod 1 bearing a brush of long setae on its carpus and merus (Fig. 7 D). Pereopod 7 ischium rostral surface with shallow depression; carpus slightly expands on tergal margin (Fig. 7 F).

Pleopods 1–5 exopods with monospiracular internal lungs (Fig. 7 G – K). Male: pleopod 1 exopod oval, outer margin sinuous, distal apex slightly concave and forming two inconspicuous lobes, inner lobe bearing one seta near apex (Fig. 7 G). Pleopod 2 exopod almost triangular, slightly concave on outer margin (Fig. 7 H). Pleopod 1 endopod with broad basal part, narrowed towards apical apex, apex bearing several setae, bent outwards and ending with two pointed tips (Fig. 7 G); pleopod 2 endopod longer than exopod, distal article thin and long (Fig. 7 H).

Etymology.

Latin parvus = small. The new species name refers to the pleopod 1 with a small exopod. We suggest the Chinese common name as “ 小蒙潮虫 ”.

Distribution.

China (Liaoning, Jilin).