Taxonomic Study on the Selected Nereidid Species (Annelida: Polychaeta) from Northeast Asian Waters Based on Morphology and Molecular Data

Abstract

7. Three species (Hediste didroma, Nereis tigrina, and Perinereis shikueii) are newly reported from Korean waters. Furthemore, two unknown species were collected from Korean waters during field survey for this study. They are described as new species: Nereis sp. nov 2 and Composetia sp. nov. At present, 105 nominal nereidid species have been reported from Northeast Asian waters. As a result of this study, 80 species might be valid although some of these are uncertain. Among these, 51 species are endemic to this region.

Pseudonereis variegata (Grube, 1857)

Hediste japonica (Izuka, 1908)

Nereis denhamensis Augener, 1913

N. vexillosa Grube, 1851

N. pelagica Linnaeus, 1758

N. multignatha Imajima and Hartman, 1964

Platynereis bicanaliculata (Baird, 1863)

Cheilonereis cyclurus (Harrington, 1897)) from Northeast Asian waters. The result of taxonomic revision of 27 selected nominal species based on molecular and morphological data are as follows: 1. Present taxonomic status of ten nominal species (Hediste atoka Sato and Nakashima, 2003

H. diadroma Sato and Nakashima, 2003

Nectoneanthes oxypoda (Marenzeller, 1879)

N. uchiwa Sato, 2013

N. heterocirrata Treadwell, 1931

N. tigrina Zachs, 1933

Perinereis aibuhitensis (Geube, 1878)

P. linea (Treadwell, 1936)

P. mictodonta (Marenzeller, 1879)

P. shikueii Glasby and Hsieh, 2006) are confirmed by COI sequence comparison and morphological observation

2. More than four cyptic species were determined from four species (Hediste japonica

Nereis multignatha

Perinereis wilsoni

Platynereis bicanaliculata) and one is newly described (Nereis sp. nov. 3 from N. multignatha)

3. Seven species reported from Northeast Asia (Perinereis floridana (Ehlers, 1868)

P. cultrifera

Nereis denhamensis

N. pelagica

N. vexillosa

N. neoneanthes Hartman, 1948

Pseudonereis variegata) have been misidentified. Perinereis floridana and P. cultrifera turned out to be P. euiini Park and Kim, 2007

Nereis denhamensis and N. vexillosa turned out to be N. sp. nov. 1 and N. sp. 4, respectively. Pseudonereis variegata turned out to be a new species. Nereis neoneanthes is newly identified as N. multignatha. Nereis pelagica turned out to be an undescribed species, however, further study of morphology is needed to describe it

4. Cheilonereis cyclurus differs from its type specimen. Cheilonereis shishidoi is reinstated which was a junior synonym of C. cyclurus based on examination of topotype materials and molecular comparison

5. Two nominal species Nereis (Neanthes) orientalis Treadwell, 1936 and Perinereis vancaurica tetradentata Imajima, 1972 are newly synonymized to P. linea based on their type specimens

6. Alitta brandti Malmgren, 1865 and Pseudonereis anomala Gravier, 1901 turned out to be misidentified and, further taxonomic study is needed to confirm their taxonomic status

A taxonomic study was carried out on the nereidid species from Northeast Asian waters. A total of 105 nominal species were compiled based on literatures. Of these, 27 taxonomically ambiguous nominal species were selected and reexamined through molecular and morphological analyses based on type and non-type specimens. An approach of reverse taxonomy was applied to examine taxonomic validity of selected nereidids based on COI sequences. Totally 234 sequences from 32 nereidid species including comparative species were analyzed. These analyses revealed the likely presence of undescribed or misidentified species among previously reported nereidids (Perinereis wilsoni Glasby and Hsieh, 2006

P. cultrifera (Grube, 1840)