MORINOIA AOSEN HOU SP. NOV.

(FIGS 4–10)

Z o o b a n k r e g i s t r a t i o n: u r n: l s i d: z o o b a n k. org:act: 5DB813D0-FDE9-45D8-B0E3-40336A28DF25

Type species: Morinoia paludosus (Cheng et al., 2011) . Material examined: Holotype ♂, 8.5 mm; CHINA, Beijing, Chaoyang District, lakeside along Aosen (short name in Chinese for Olympic Forest Park); 40.01 N, 116.37 E; 67 m a.s.l.; 16 November 2017; collected by Hongguang Liu and Zhonge Hou; IZCAS-I-A1700–1. Paratype. ♀, 7.6mm; same data as for preceding; IZCASI-A1700–2. Other materials, two males and two females (IZCAS-I-A1700–3, 4, 5, 6), same data as holotype. All type specimens are deposited in the Institute of Zoology, Chinese Academy of Sciences (IZCAS) in Beijing, China .

Etymology: The specific name refers to the type locality and is a noun in apposition.

Diagnosis: Male gnathopod I carpus subtriangularshaped, with tumescent humps at posterodistal angle, female gnathopod II carpus and propodus tumescent posteriorly; uropod III peduncle with two spines on distal corner, ramus slightly shorter than peduncle; telson with one or two distal spines and rounded on distal margin.

Description: Male (IZC AS-I-A1700–1), 8.5 mm (Fig. 4A). Head: Eyes rounded, inferior antennal sinus distinct. Antenna I (Fig. 6A): short, reaching end of peduncular article 4 of antenna II; peduncular articles 1–3 subequal in length; flagellum with four articles. Antenna II (Fig. 6A): peduncular article 5 slightly longer than article 4, with short spines on both margins; flagellum with 12 articles, each article with some setae. Upper lip (Fig. 5A): convex, with minute setae. Mandible (Fig. 5B, C): left mandible incisor five-dentate, lacinia mobilis with five weak teeth. Right mandible incisor five-dentate, lacinia mobilis bifurcate, with weak definitions, molar triturative with one long seta. Maxilla I (Fig. 5D, E): inner plate with two plumose distal setae, outer plate with nine apical serrated spines. Maxilla II (Fig. 5F): inner plate with one plumose seta at medial margin, outer plate with setae on apical margin and outer margin. Lower lip (Fig. 5G): concave, with fine setae. Maxilliped (Fig. 5H): inner plate with some plumose setae on distal margin; outer plate with apical setae; articles 1–2 of palp broad, article 4 distinct.

Pereon: Gnathopod I (Fig. 6C): basis with short spines on anterior and posterior margins; merus without tumescent humps, posterior margin with spines;

carpus subtriangular-shaped, with tumescent humps at posterodistal angle, and three spines at base of hump; propodus about 0.7 times as long as carpus, with tumescent hump at posterodistal angle, with rows of spines, palmar margin with stiff setae; dactylus shorter than palm. Gnathopod II (Fig. 6D): coxal plate with four spines on ventral margin; anterior margin of basis bare; propodus 1.26 times as long as wide, palmar margin convex and fringed with spines; dactylus bare on both margins.

Pereopods III–VII (Fig. 7): Pereopod III (Fig. 7A) longer than pereopod IV (Fig. 7B); carpus of pereopod IV shorter than that of pereopod III; propodus with a distal spine at dactylar hinge; dactylus cuspidactylate. Pereopod V (Fig. 7C): almost as long as pereopod III, coxal plate bilobed, anterior lobe slightly larger than posterior lobe, bearing setae on posterior lobe; posterior margin of basis expanded, with seven short spines, anterior margin with eight spines; merus, carpus and propodus with spines on anterior and posterior margins. Pereopod VI (Fig. 7D): much longer than pereopod V, coxal plate bilobed; basis subrounded with eight spines on anterior margin and six setae on posterior margin; merus, carpus and propodus with spines on anterior and posterior margins; dactylus slender. Pereopod VII (Fig. 7E): as long as pereopod VI, coxal plate small; basis strongly expanded, with 11 short spines on anterior margin and nine setae on posterior margin; merus, carpus and propodus with spines on anterior and posterior margins; dactylus 0.29 times as long as propodus. Coxal gills: present on gnathopod II and pereopods III–VI.

Pleon: Epimeral plates (Fig. 6B) with slightly pointed posterior angles, ventral margin unarmed, posterior margin with two or three minute setae. Pleopods (Fig. 10E): similar to each other; peduncle about 1.2 times as long as rami, inner and outer rami nearly the same length, both rami fringed with plumose setae.

Urosome: Uropod I (Fig. 6E): peduncle longer than rami, with five and four spines on outer and inner margins, respectively; outer ramus a little shorter than inner ramus, outer ramus marginally bare, with four distal spines; inner ramus with one spine on outer margin, three spines on inner margin and five distal spines. Uropod II (Fig. 6F): peduncle subequal in length with rami, with three spines on outer margin; inner ramus with two spines on outer margin and one spine on inner margin, outer ramus with one marginal spine. Uropod III (Fig. 8A, B): peduncle with two spines on distal corner, ramus slightly shorter than peduncle, with one lateral spine, and two or four distal spines. Telson (Fig. 9A, B): bilobed, longer than wide, apically notched, each lobe with one or two distal spines and two or three facial spines.

Description of paratype female: (IZCAS-I-A1700–2), 7.6 mm (Fig. 4B). Head: Antennae I–II (Fig. 10A) similar to those of male.

Pereon: Gnathopod I (Fig. 10B): carpus and propodus not tumescent, propodus parallel-sided, with spines ramus (ramus subequal in length to peduncle in uropod III; Fig. 8C, D); telson rounded on distal margin (sharp on distal margin; Fig. 9D); telson with one or two distal spines (with three spines). along anterior and posterior margins, palmar margin short, with four slender spines at posterodistal corner; cuspidactylate. Gnathopod II (Fig. 10C, D): coxal plate with cuspidate posterior margin; basis anteriorly broad, anterior margin with many minute spines; merus with small facial spines; carpus and propodus tumescent posteriorly; propodus with spine-row on lateral surface, palm margin with stiff setae; dactylus about half of palmar margin, with a seta at hinge of nail.

Pereopods III–VII: similar to those of male. Oostegites present on gnathopod II and pereopods III–V.

Remarks: Morinoia aosen is similar to M. paludosus and M. japonica in antenna I shorter than antenna II, gnathopods I–II sexually dimorphic and the shape of pereopods III–VII. The new species can be distinguished from M. paludosus by the following characters ( M. paludosus in parentheses): the tip of ramus in uropod III blunt (with a sharper ramus of uropod III; Fig. 8E–G); the peduncle of uropod III longer than ramus (the peduncle of uropod III almost same length as ramus); telson rounded on distal margin (sharp on distal margin; Fig. 9C); telson with one or two distal spines (with three or four distal spines).

The new species can be distinguished from M. japonica by the following characters ( M. japonica in parentheses): the peduncle of uropod III longer than