Morphological Redescription of Two Newly Recorded Assimineid Species (Gastropoda: Assimineidae) from South Korea

초록

The family Assimineidae comprises a diverse group of gastropods found in temperate to tropical regions. In this study, we report the first records of two assimineid species, Assiminea parasitologica and Angustassiminea satumana, from South Korea, based on specimens collected from estuarine and intertidal zones along the southern and western coasts of South Korea and Jeju Island. We present detailed morphological redescriptions of both species, including shell and radular characters. Assiminea parasitologica is characterized by its small, ovate, brownish shell with a bright spiral zone near both the sutural area and the base of the body whorl. This species typically inhabits salt marshes and often co-occurs with other Assiminea species. Angustassiminea satumana, exclusively from Jeju Island, has a moderately elongated, glossy shell with a yellowish-brown coloration and a translucent white body. Molecular identification using mitochondrial cytochrome c oxidase subunit I (COI) sequences confirmed our species identification of As. parasitologica and An. satumana based on shell morphology. The mitochondrial DNA COI sequences of As. parasitologica clustered with As. grayana as its sister species in maximum likelihood analysis, supporting its morphological identification. Angustassiminea satumana was clustered with a COI sequence obtained from a Chinese specimen, exhibiting 98% sequence identity. This study contributes to the taxonomy of Assemineidae by providing integrative morphological and molecular data for two newly recorded species in the Korean fauna.

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