Sea-land transition drove terrestrial amphipod diversification in East Asia, with a description of a new species Author Liu, Hongguang Author Tong, Yan Author Zheng, Yami Author Li, Shuqiang Author Hou, Zhonge text Zoological Journal of the Linnean Society 2022 2022-10-01 196 2 940 958 https://academic.oup.com/zoolinnean/article/196/2/940/6529773 journal article 162759 10.1093/zoolinnean/zlab119 463ea041-e53f-4bd9-954b-c34f8806fcf5 0024-4082 7184373 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. Figure 4. Morinoia aosen sp. nov. from Beijing. A, male, holotype, IZCAS-I-A1700–1, 8.5 mm. B, female, paratype, IZCASI-A1700–2, 7.6 mm. Pereon: Gnathopod I ( Fig. 6C ): basis with short spines on anterior and posterior margins; merus without tumescent humps, posterior margin with spines; Figure 5. Morinoia aosen sp. nov. male holotype, from Beijing. A, upper lip. B, left mandible. C, right mandible. D–E, maxilla I. F, maxilla II. G, lower lip. H, maxilliped. Figure 6. Morinoia aosen sp. nov. male holotype, from Beijing. A, antennae I–II. B, uropods. C, gnathopod I. D, gnathopod II. E, uropod I. F, uropod II. 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. Figure 7. Morinoia aosen sp. nov. male holotype, from Beijing. A, pereopod III. B, pereopod IV. C, pereopod V. D, pereopod VI. E, pereopod VII. 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. Figure 8. The uropod III in Morinoia species. A , B, uropod III of Morinoia aosen sp. nov. C, D, uropod III of M. japonica . E–G, uropod III of M. paludosus . White arrows show the interspecific difference and black arrows show the intraspecific difference. Images of M. paludosus and M. japonica modified from Cheng et al. (2011) . Figure 9. The telson in Morinoia species. A , B, telson of Morinoia aosen sp. nov. C, telson of M. paludosus . D, telson of M. japonica . White arrows show the interspecific difference. Images of M. paludosus and M. japonica modified from Cheng et al. (2011) . 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