A survey and morphological study of plerocercoidal Nybelinia surmenicola (Cestoda: Tentaculariidae) in the common squid from the Korean coastal waters

Trypanorhych plerocercoids of Nybelinia surmenicola are described in the common squid, Todarodes pacificus, through the use of light and scanning electron microscopy. Upon dissection, out of 200 common squid from the Korean coastal water, 54 (27%) were found infected with N. surmenicola plerocercoids. Mean N. surmenicola abundance was 2.28 per squid. Body length and width ranged from 6.1-11.1 (8.05) × 2.0-2.2 (2.1) mm. Bothria are broad, bean-shaped, measured 2.4-2.8 × 0.62-0.69 (2.65 × 0.64) mm. The short and long tentacular armatures which are spirally arranged are homeoacanthous and homeomorphous uncinate hooks and consist of compact rose-thorn-shaped tentacular hooks. The tentacle sheaths are coiled in a spiral near the bulbs. Four large bothria are separated by filiform microtriches along the bothridal margins. This is the first description of the plerocercoids of N. surmenicola in the common of squid from the Korean coastal waters.