Two new temporary ectoparasitic isopods (Cymothoida: Cymothooidea) from Korean waters with a note on geographical distributions of Rocinela Leach, 1818 and Gnathia Leach, 1814

Sung Hoon Kim; Jong Guk Kim; Seong Myeong Yoon

doi:10.7717/peerj.14593

Two new temporary ectoparasitic isopods (Cymothoida: Cymothooidea) from Korean waters with a note on geographical distributions of Rocinela Leach, 1818 and Gnathia Leach, 1814

PeerJ. 2023 Jan 3:11:e14593. doi: 10.7717/peerj.14593. eCollection 2023.

Authors

Sung Hoon Kim¹, Jong Guk Kim², Seong Myeong Yoon^{3

4}

Affiliations

¹ Division of Ocean Sciences, Korea Polar Research Institute, Incheon, South Korea.
² Division of Zoology, Honam National Institute of Biological Resources, Mokpo, South Korea.
³ Educational Research Group for Age-associated Disorder Control Technology, Graduate School, Chosun University, Gwangju, South Korea.
⁴ Department of Biology, College of Natural Sciences, Chosun University, Gwangju, South Korea.

Abstract

Two new species of temporary ectoparasitic isopods, Rocinela excavata sp. nov. and Gnathia obtusispina sp. nov., are reported from the southern Islands of the Korean Peninsula. Rocinela excavata sp. nov. is distinguishable from its related species by the following characteristics: (1) laterally stepped rostrum; (2) separated eyes; (3) propodal blade having eight robust setae; and (4) merus having four or five blunt robust setae in pereopods 1-3. Gnathia obtusispina sp. nov. differs from its congeners by the combination of the following characteristics: (1) body covered with numerous tubercles and setae, (2) cephalon having tooth-like paraocular ornamentations; and (3) frontal border having two inferior frontolateral processes. These two new species are the 13^th Rocinela species and 19^th Gnathia species in the temperate Northern Pacific region, respectively. Discovery of these new species represents high species diversity of the genera Rocinela Leach, 1818 and Gnathia Leach, 1814 worldwide as well as in the Northern Pacific region. In addition, faunal diversity analysis on the members of both genera revealed that Rocinela species show high-latitude diversity whereas Gnathia species have low-latitude diversity.

Keywords: Ectoparasite; Gnathia; Isopods; Morphology; Rocinela; South Korea; Taxonomy.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Coleoptera*
Eye
Isopoda*
Republic of Korea

Grants and funding

This study was supported by research funds from Chosun University (2022) and a grant (201902204) of the National Institute of Biological Resources (NIBR) funded by the Ministry of Environment (MOE), the Republic of Korea. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.