Nemerteans in Vostok Bay: 40 Years of Study

Nemertean worms in Vostok Bay (Sea of Japan) have been consistently studied over the past 40 years. To date, a total of 54 nemertean species have been identified from this water body (or 68% of all nemertean species recorded from Peter the Great Bay), of which 10 species known for Russian waters have been found in Vostok Bay only. Seventeen species remain undescribed. A description of Tetrastemma aequicolor sp. nov., previously known as Quasitetrastemma nigrifrons var. aequicolor, is provided here. Three heteronemertean species from Vostok Bay are known only at the larval stage due to molecular genetics studies of their pilidia. Four species (“Lineus” bilineatus sensu Iwata, Kulikovia torquata, Paranemertes peregrina, and Protetrastemma viride), previously reported for Vostok Bay, have not been found here and all over Peter the Great Bay for the past 16 years or more.