Coronatella trachystriata (Chen, Zhang and Liu,

Lee, Sue Yeon, Yoo, Jung Sun & Kim, Seung Tae, 2017, Recent progress in studies of the Cladocera (Crustacea: Branchiopoda) of South Korea with seven new records for the Korean Peninsula, Journal of Species Research 6, pp. 227-246 : 242-243

8. Coronatella trachystriata (Chen, Zhang and Liu,

1994) ( Fig. 10)

Material deposited to NIBR. 2 parthenogenetic females from Yongsuji (Reservoir) (N 33.31752°, E 126.1892°), Jeju-do, coll. in 15 Feb 2012 by H.G. Jeong, NIBRIV 0000812490 .

Parthenogenetic female. Body ( Fig. 10A) low oval, strongly compressed laterally, with maximum height at body middle. Dorsal margin of carapace convex; postero-dorsal and postero-ventral angles broadly rounded. Posterior margin strongly convex. Postero-dorsal angle without denticles, with numerous thin setules not organized into groups. Valves with prominent linear longitudinal sculpture. Head small, rostrum in lateral view rath- er broad, protruding downwards. Ocellus of moderate size, compound eye larger than ocellus. Postabdomen ( Fig. 10B, C) short, moderately wide, with almost parallel margins in postanal portion, length about 2 heights, its Ventral margin convex, distal margin convex, distal angle broadly rounded, dorsal margin convex in postanal portion and concave in anal one, with distal part about 1.5 times longer than preanal one, anal and postanal portions of similar length. Preanal angle well-defined, postanal angle smooth. Postanal margin with 5-6 clusters of 2-6 small sharp teeth, length of longest tooth slightly smaller than the width of postabdominal claw base. Postanal portion with 4-5 broad lateral fascicles of setules, posteriormost setule of each fascicle as thin as others, two times longer than neighboring marginal teeth. Postabdominal claw of moderate length, slightly shorter than preanal portion of postabdomen. Basal spine slender, about 0.2 claw length. Antenna I typical for genus, Antenna II with antennal formula: setae 0-0-3/?-1-3; spines 1-0-1/0-0-1. Branches with proximal segments longer than others. Seta arising from middle segment of endopod of similar size to that of apical setae. Spine on proximal segment of exopod longer than its middle segment. Spines on apical segments longer apical segments. Limb I ( Fig. 10D, E) with IDL having two setae, seta 1 absent. Seta 3 large and thick, strongly curved, with a large spine in middle and thin posterior portion, armed with this setules; seta 2 two times thinner and 1.5 times shorter than seta 3, armed with long thick spinules. Endites 1 and 2 without inner setae. Endite 2 with seta e 1.5 times longer than seta f.

Notes. Only two specimens were found in a single sample from Jeju Island. In outer morphology these were similar to the East Asian species C. trachystriata , but differed in several characters and probably represents a new species. IDL morphology in studied specimens is unique for the genus Coronatella Dybowski et Grochowski (see Van Damme and Dumont, 2008; Sousa et al., 2015; Van Damme, 2016), all other species have IDL seta 2 and 3 of similar size and morphology, both either have strong spines in middle or armed by thin spinules only. It also differs from both C. trachistriata and C. rectangula (also common in Korea, See Yoon, 2000) in morphology of lateral fascicles of setules, with a thin distalmost setule in each fascicle.

This is a new record for the Korean Peninsula, but populations of Coronatella sp. from Jeju Island need to be re-studied based on better material.