In May 2023, a free-living marine nematode species from the genus Parapinnanema was identified in the subtidal zone of Ulleungdo Island, the East Sea, Korea. Specimens were collected using the Smith-McIntyre Grab. These specimens exhibited close similarities to Parapinnanema imbricatum from the sublittoral of Moneron Island, particularly in terms of general characteristics, such as the detailed structure of the buccal cavity, the complex and ringed structure of the cuticle, the copulatory apparatus, spinneret, and the female genital system. However, the Korean specimens of Parapinnanema imbricatum also displayed distinctive features compared to the original description, including a relatively elongated body (3,317-4,339 μm vs. 3,100-4,200 μm) and a narrower body width (66-77 μm vs. 71-85 μm). Additionally, the diameter of the head was relatively shorter (24-29 μm vs. 28-36 μm). This paper offers a comprehensive morphological description, along with illustrations and DIC photomicrographs, of P. imbricatum from Korean waters.

1. INTRODUCTION
2. MATERIALS AND METHODS
3. SYSTEMATIC ACCOUNTS
4. DISCUSSION
CRediT authorship contribution statement
Declaration of Competing Interest
ACKNOWLEDGEMENTS
REFERENCES

• Woo In Jung(East Sea Environment Research Center, Korea Institute of Ocean Science and Technology, Uljin 36315, Republic of Korea)
• Won Gi Min(East Sea Environment Research Center, Korea Institute of Ocean Science and Technology, Uljin 36315, Republic of Korea)
• Hyun Soo Rho(East Sea Environment Research Center, Korea Institute of Ocean Science and Technology, Uljin 36315, Republic of Korea) Corresponding author