New extension range and complementary description of Eurytemora americana (Calanoida: Temoridae) in northern Korea

Seong Yong Moon,Jung-Hwa Choi,Sun-Kil Kim,Jung-Nyun Kim,Balu Alagar Venmathi Maran

doi:10.1186/s41200-016-0076-8

Abstract

The brackish calanoid, Eurytemora americana Williams, 1906, is reported in the northern part of Korea. It is found to be an important copepod in the mesozooplankton community structure from the estuarine and shallow waters. The range extension and of E. americana is reported additionally to previously known distributional range from brackish waters of the South Atlantic Ocean, United Kingdom, Canada, English Channel, Iceland, the North Atlantic Ocean, the North Pacific Ocean (Japan, Korea, and Russia), and the North Sea. In this study, both sexes of E. americana are redescribed and illustrated including their undescribed mouthparts. The most important characters that have been overlooked in the previous descriptions are: shape of the last pedigerous somite in female, structure of the genital double-somite, and ornamentation of the fifth leg in both sexes. The distributional range of E. americana is now given with its northern and southern hemisphere limit as 70 to 37°N in the North Pacific and 38°S in the Southwest Atlantic.

Highlights

The brackish calanoid, Eurytemora americana Williams, 1906, is reported in the northern part of Korea
In the materials collected of the studied area, the predominant species was E. americana Williams, 1906, it co-occurred with E. pacifica Sato, 1913
In the current re-examination of the obtained materials, we have found that E. americana was erroneously identified as E. pacifica, while E. pacifica was rare in these waters

Summary

Introduction

The brackish calanoid, Eurytemora americana Williams, 1906, is reported in the northern part of Korea. Two of Eurytemora species E. composita Keiser, 1929 and E. pacifica Sato, 1913 have so far been recorded. We have conducted the faunistic studies on the calanoids in eastern estuarine and shallow waters of Korea from May to June 2011. In the materials collected of the studied area, the predominant species was E. americana Williams, 1906, it co-occurred with E. pacifica Sato, 1913. The complete redescription of E. americana from the eastern Korea estuarine and shallow waters is presented to clarify the identification of the northern Korean calanoid reported as E. pacifica to avoid possible misunderstanding of the identity of the species

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Discussion

Conclusion