Records of Adult Caligiform Copepods (Crustacea: Copepoda: Siphonostomatoida) in Marine Plankton from East Asia, Including Descriptions of Two New Species of Caligus (Caligidae) Author Venmathi Maran, B. A. Marine Ecosystem Research Division, Korea Institute of Ocean Science & Technology, Ansan P. O. Box 29, Seoul 425 - 600, Korea E-mail: bavmaran @ gmail. com & Takehara Marine Science Station, Setouchi Field Science Centre, Graduate School of Biosphere Science, Hiroshima University, 5 - 8 - 1 Minato-machi, Takehara, Hiroshima 725 - 0024, Japan E-mail: ohtsuka @ hiroshima-u. ac. jp bavmaran@gmail.com&ohtsuka@hiroshima-u.ac.jp Author Ohtsuka, Susumu Takehara Marine Science Station, Setouchi Field Science Centre, Graduate School of Biosphere Science, Hiroshima University, 5 - 8 - 1 Minato-machi, Takehara, Hiroshima 725 - 0024, Japan E-mail: ohtsuka @ hiroshima-u. ac. jp & Corresponding author ohtsuka@hiroshima-u.ac.jp Author Shang, Xu Wenzhou Medical College, Gao Jiao Yuan Qu, Chashan, Wenzhou, Zhejiang 325035, China text Species Diversity 2012 2012-11-25 17 2 201 219 https://www.jstage.jst.go.jp/article/specdiv/17/2/17_KJ00008425371/_article journal article 10.12782/sd.17.2.201 2189-7301 4649334 B59C9BBF-B456-4CD9-B646-88ECC92ED28B Caligus rotundigenitalis Yü, 1933 ( Fig. 8C ) Caligus rotundigenitalis Yü, 1933: 118 ; Rangnekar 1959: 43 ; Yamaguti 1963: 59 ; Pillai and Natarajan 1977: 31 ; Pillai 1985: 348 ; Ho and Sey 1996: 65 ; Ho et al. 2000: 177 ; Ho and Lin 2001: 193 ; Grobler 2004: 141 ; Venmathi Maran et al. 2009: 797 ; Nagasawa et al. 2010: 103 . Caligus multispinosus (not Shen, 1957 ): Lin et al. 1994: 259 ; 1997: 1483; Lin and Ho 1998b: 96 . Material examined . One adult ♂ (XOB-PC12), Amoy (=Xiamen), Fujian Province , China (St. 1), 20 September 2008 ( Table 1 ) . Description . Male. Body ( Fig. 8C ) 1.38 mm long, excluding caudal setae. Cephalothoracic shield slightly wider than long, 0.71 mm × 0.75 mm . Fourth pediger wider than long, 0.14 mm × 0.30 mm . Genital complex subquadrate, small, longer than wide, 0.24 mm × 0.20 mm . Abdomen distinctly 2-segmented, longer than wide, 0.20 mm × 0.12 mm . Caudal ramus longer than broad, 0.08 mm × 0.05 mm , armed with 3 short and 3 long plumose setae. Remarks . This is the first record of C. rotundigenitalis in a plankton sample. Four other species of Caligus have hitherto been reported from plankton samples in China ( Shen and Li 1959 ), including three species of which the hosts are as yet unknown, viz. , C. aduncus Shen and Li, 1959 , C. costatus Shen and Li, 1959 , and C. undulatus Shen and Li, 1959 . Distribution . Caligus rotundigenitalis is one of the most common caligids on cultured and wild fishes in Asia ( Ho et al. 2000 ; Venmathi Maran et al. 2009 ; Nagasawa et al. 2010 ). It shows low host-specificity, utilizing a total of 32 fish species in 19 families as hosts in Taiwan ( Ho et al. 2000 ).