Caligus rotundigenitalis Yü, 1933

Venmathi Maran, B. A., Ohtsuka, Susumu & Shang, Xu, 2012, Records of Adult Caligiform Copepods (Crustacea: Copepoda: Siphonostomatoida) in Marine Plankton from East Asia, Including Descriptions of Two New Species of Caligus (Caligidae), Species Diversity 17 (2), pp. 201-219 : 212

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).

Figures

Fig. 8. Three previously described species of Caligus found in plankton samples. A, Caligus orientalis Gusev, 1951, female (KMNH IvR 500,503), habitus, dorsal view; B, C. orientalis, male (KMNH IvR 500,504), habitus, dorsal view; C, C. rotundigenitalis Yu, 1933, male (XOB- PC12), habitus, dorsal view; D, C. undulatus Shen and Li, 1959, female (KMNH IvR 500,505), habitus, dorsal view; E, C. undulatus, male (KMNH IvR 500,506), habitus, dorsal view.Scale bars: 1mm (A–E), 0.5mm (C).