A NEW SPECIES OF AEGIDAE (ISOPODA, CYMOTHOIDA) FROM THE SOUTH CHINA SEA BY HAI-YAN YU1) Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, P. R. China ABSTRACT Aega nanhaiensis sp. nov. is described and figured from the South China Sea. Brief comments are given on the relationship of the new species to allegedly related species of the genus. Aega nanhaiensis is characterized by the expansion of articles 1 and 2 of the antennular peduncle, a moderate eye-size, a large distal, robust seta on the propodus of pereopod 3, and the shape and setation of the uropods. RÉSUMÉ Aega nanhaiensis, espèce nouvelle du sud de la mer¯ de Chine est décrite et illustrée. De brefs commentaires sur les inter-relations de cette nouvelle espèce avec les autres espèces supposées proches dans le genre sont donnés. Aega nanhaiensis est caractérisé par l’extension des articles 1 et 2 du pédoncule antennulaire, un œil de taille moyenne, une soie large, robuste et distale sur le propodite du péréiopode 3, et la forme et les soies des uropodes. INTRODUCTION The Aegidae are a small family of marine isopods; currently approximately 140 species in 7 genera have been reported worldwide and more than 60% of these species are accommodated in the genus Aega Leach, 1815 (cf. Schotte et al., 1995). Although the family Aegidae has received some attention in adjacent areas, such as Japan (Numonura, 1981a, 1988, 1993, 2006; Bruce, 1996, 2004) and the Philippines (Richardson, 1910), our knowledge of the aegids in Chinese waters remains poor. There exists no guide to the isopods of China, nor is there a major review of the Aegidae of the region. The only recent contributions on Chinese 1) e-mail: [email protected] © Koninklijke Brill NV, Leiden, 2007 Crustaceana 80 (8): 909-915 Also available online: www.brill.nl/cr 910 HAI-YAN YU aegids were those of Nunomura (1981b), Kensley & Chan (2001), and Yu & Bruce (2006). Examination of the isopod collections deposited in the Institute of Oceanology, Chinese Academy of Sciences (IOCAS), revealed one male and two female specimens not covered by the described species of the genus Aega. Consequently, these are here in described as a new species. MATERIAL AND METHODS Specimens were examined and drawn with a dissection microscope (Nikon SMZ 1500). Measurements were recorded using an eyepiece micrometer. Description follows the characters used by Bruce (e.g., 2004). Types are deposited in the Institute of Oceanology, Chinese Academy of Sciences (IOCAS), Qingdao, China. TAXONOMY Suborder CYMOTHOIDA Wägele, 1989 Family AEGIDAE WHITE, 1850 Genus Aega Leach, 1815 Aega nanhaiensis sp. nov. (figs. 1-3) ◦ Material examined. — Holotype: (21 mm), IOCAS N206B-72, South China Sea, 20 50 N ◦ 109 50 E, trawled, 115 m, sand and mud, 14 May 1960, coll. Shen Shoupeng. Paratypes: (27 ◦ ◦ mm), IOCAS 30-25, South China Sea, 20 50 N 113 00 E, sand and mud, trawled, 85 m, 16 February ◦ ◦ 1959, coll. Li Huanlin; (27 mm), IOCAS S68B-22, South China Sea, 21 00 N 114 00 E, trawled, 85 m, 8 April 1959, coll. Zhang Weiquan. Description of holotype. — Body about 3 times as long as wide, dorsal surfaces punctate, lateral margins subparallel. Rostral point projecting anteriorly, not ventrally folded. Eyes of moderate size, not medially united, each eye made up of ∼17 transverse rows of ommatidia, each row with ∼8 ommatidia; eye colour dark brown. Pereonite 1 longest, coxae 2-7 each with posteroventral angle rounded. Pleonite 1 not covered by pereonite 7. Pleotelson truncate, 0.8 times as long as anterior width, dorsal surface with depression near anterior margin, posterior margin with small tubercles. Antennule with peduncle articles 1 and 2 flattened, article 2 with anterodistal lobe reaching 1/3 of article 3, articles 3 and 4 together 0.8 times as long as combined lengths of articles 1 and 2; flagellum with 11 articles, extending to midpoint of eye. Antenna with inferior surface of peduncle article bearing a groove; article 4 is 0.9 times as long as combined lengths of articles 1-3, with deep longitudinal groove, inferior margin with 1 plumose seta and 1 simple seta; article 5 not markedly wider than article 4, inferior margin with 2 plumose setae, anterodistal angle with cluster of 5 simple setae; flagellum with 11 articles, extending to posterior margin of pereonite 1..