Systematic study on the Korean pilumnoids and xanthoids (Crustacea: Decapoda: Brachyura) based on morphology and molecular data

Abstract

A systematic study was conducted on the Korean pilumnoid and xanthoid crabs. The specimens, deposited in the Laboratory of Systematics and Molecular Evolution in Seoul National University since 1950, were examined for the present study. They have been collected from the intertidal and shallow subtidal zones in Republic of Korea. As a result, 18 species of 12 genera and 28 species of 24 genera were identified in the superfamily Pilumnoidea and the superfamily Xanthoidea, respectively. The updated checklist and the key to species of Korean pilumnoids and xanthoids were provided herein. A total of 46 speceis have been recorded with the specific characters including the pictures, the illustrations. Moreover, their distribution in Korean peninsular and the worldwide was displayed on the map, and their habitats were investigated. Of these, one pilumnoid and 8 xanthoids were first recorded from Korea: Actaea polyacantha (Heller, 1861), Actaeodes hirsutissimus (Rüppell, 1830), Atergatopsis germaini A. Milne-Edwards, 1865, Danielea noelensis (Ward, 1934), Etisus anaglyptus H. Milne Edwards, 1834, Gaillardiellus rueppelli (Krauss, 1843), Lybia caestifera (Alcock, 1898), Neoactumnus convexus Sakai, 1965, and Platypodia tomentosa (De Man, 1902). The mtCOI sequences from 26 species of the Korean pilumnoids and xanthoids were obtained, and examined by DNA barcoding method. The some suspected cryptic species or misidentified specimens were discovered, and then molecular taxonomic relationship among them was inferred by Baysian inferences and Maximum likelihood. According to Baysian inferences tree, a significant taxonomic relationship was found as follows: 1) Neoliomera insularis would be questioned their taxonomic status, 2) Based on the relationship between Leptodius nigromaculatus and L. affinis, the two species were the same species, 3) Actaea bocki (Odhner, 1925) would be considered to examined their taxonomic status, 4) Korean Medaeops granulosus would be not real M. granulosus or a cryptic species. Zehntneriana villosa (Zehntner, 1894) were examined and redescribed with illustrations herein with the illustration. Zehntneriana villosa from Japan, used to establish the genus Zehntneriana, was found out to be a new species. As a result of the revision of the genus Leptodius A. Milne-Edward, 1863, the genus Leptodius are consisting 10 speices: L. acutidens (Stimpson, 1907), L. affinis (De Haan, 1835), L. australis Ward, 1936, L. davaoensis Ward, 1941, L. exaratus A. Milne-Edwards, 1834, L. gracilis Dana, 1852, L. planus Ward, 1834, L. sanguineus A. Milne-Edwards, 1834, and L. nudipes (Dana, 1853). As regards recorded five species of recent checklist, Leptodius nigromaculatus Serène, 1962 would be synonymized as L. affinis (De Haan, 1835). Leptodius philippinensis Ward, 1941 and L. hombronii (Lucas, in Jacquinot & Lucas, 1853) would be synonymized as L. sanguineus. Leptodius efference Rathbun, 1907 and L. waialuanus Rathbun, 1906 would be considered to transfer to the genus Liocarpilodes Klunzinger, 1913 and the genus Etisus H. Milne Edwards, 1834, respectively.