First Report on Three Lesser-Known Magelona Species from Korean Waters: Details of All Thoracic Chaetigers and Methyl Green Staining Patterns

Abstract

This study assessed the taxonomic statuses of three lesser-known Magelona F. Müller, 1858 species collected from intertidal to sublittoral habitats in Korean coastal waters, basing identification on morphological features and comparing them with their closest congeners. We present a comprehensive description and illustration of taxonomically significant and standardized characters, covering all thoracic chaetigers of three newly discovered Magelona species from Korea. Within the documented Korean Magelona species, these three species exhibit the following distinctive characteristics. Magelona sachalinensis Buzhinskaja, 1985, possess diminutive superior dorsal lobes in the initial four chaetigers and specialized chaetae on chaetiger 9; Magelona lenticulata Gallardo, 1968, is characterized by foliaceous postchaetal superior dorsal lobes in chaetigers 1–8; and Magelona cf. longicornis Johnson, 1901, is distinguished by notably elongated noto- and neuropodial postchaetal lamellae on chaetiger 9. Methyl green staining patterns showed species-specific characteristics and were confirmed to be effective in distinguishing the examined Korean species from each other and useful for making comparisons with previously reported Magelona species. Our study suggests that further comprehensive research on the morphological and genetic characteristics of Magelona species will enhance our understanding of their diversity.