This study reports seven new records of marine gastropod species from Korean waters: Marsenina uchidai, Littoraria sinensis, Conus litteratus, Pleurobranchus forskalii, Placida dendritica, Placida kevinleei, and Thuridilla lineolata. Notably, this marks the first documentation of the genus Marsenina in Korea. Specimens were collected from various locations along the Korean coast, including Goseong and Yangyang (Gangwon-do), Dokdo, Bito Island (Sacheon, Gyeongsangnam-do), and Jeju Island, between February 2025 and March 2026. Each species identification was based on diagnostic morphological characters and supported by photographs of living individuals or preserved specimens. Uncorrected p-distance analyses and maximum-likelihood (ML) phylogenetic reconstructions, using COI sequences, confirmed the taxonomic identities of the specimens. Among the species studied, Conus literatus and Placida dendritica showed significantly higher intraspecific genetic divergences compared to the other taxa, indicating a need for further taxonomic and population-level research. These findings enrich the existing inventory of marine gastropod biodiversity in Korean waters and offer foundational data for future taxonomic and biogeographic studies.

Abstract
1. INTRODUCTION
2. MATERIALS AND METHODS
3. SYSTEMATIC ACCOUNTS
SUPPLEMENTARY MATERIALS
CRediT authorship contribution statement
Declaration of Competing Interest
ACKNOWLEDGMENTS
REFERENCES

• Dae-Wui Jung(Korea Marine-Bio Laboratory, Daejeon 34130, Republic of Korea) Corresponding author
• Andrew Eunhak Lee(Korea Marine-Bio Laboratory, Daejeon 34130, Republic of Korea)
• Jong Guk Kim(Honam National Institute of Biological Resources, Mokpo 58762, Republic of Korea)
• Young Ho Koh(Department of Taxonomy and Systematics, National Marine Biodiversity Institute of Korea, Seocheon 33662, Republic of Korea)
• Won-Gi Min(East Sea Research Institute, Korea Institute of Ocean Science and Technology, Uljin 36315, Republic of Korea)