A new species of the hermit crab genus Pagurus Fabricius, 1775 (Crustacea: Decapoda: Anomura: Paguridae) from shallow coastal waters in Japan, with a checklist of the East Asian species of the genus

Abstract

A new species of hermit crab of the family Paguridae, Pagurus rectidactylus, is described and illustrated on the basis of material from inshore waters in the Seto Inland Sea and the Sea of Japan. It appears closest to P. quinquelineatus Komai, 2003, also known from Japan, but is easily distinguished from the latter by the dactylus of the right cheliped almost unarmed or armed only with a few tiny spines or tubercles, instead of dorsal and dorsomesial rows of conspicuous spines, and the more elongate and slender ambulatory legs with more numerous ventral corneous spines on dactyli and propodi. Housing is also different between the two species: the new species exclusively inhabits carcinoecia formed by a hydrozoan Stylactaria misakiensis (Iwasa, 1934), whereas P. quinquelineatus uses gastropod shells without association with coelenterates. A checklist of East Asian (Japanese Archipelago to Taiwan Island, Far Eastern Russia to northern China) species of Pagurus along with general geographical distributions is presented.

First record of two species of hermit crabs (Decapoda, Paguridae) from South Korea, with remarks on the associated hydrozoan, Hydrissa sodalis

“…The present specimens of South Korean P. rectidactylus showed some differences from the original description (Komai et al, 2015). First, there are 12 spines on the ventral margin of the dactylus of the right second pereopods in the present specimens, whereas there are 15-20 spines in the original description.…”

“…These two species, however, can be distinguished from the latter species by various morphological characters, such as armature and number of stripes of ambulatory legs, as mentioned by Komai (2003). The morphological differences between P. quinquelineatus and P. rectidactylus were discussed in detail in the original description of the latter species (Komai et al, 2015). In addition, two more morphological differences between them were observed in this study.…”

“…To our knowledge this is the first report, as part of ongoing systematic studies on South Korean hermit crabs, of P. quinquelineatus Komai, 2003 andP. rectidactylus Komai, Saito &Myorin, 2015 from South Korean waters. Since the specimens of P. rectidactylus showed some differences from the original description, the species is diagnosed and illustrated briefly.…”

“…The genus Pagurus Fabricius, 1775 has been considered as the polyphyletic group in the family Paguridea Latreille, 1802(McLaughlin et al, 2007Mantelatto et al, 2009;Olguin & Mantelatto, 2013) and consists of 177 species worldwide (McLaughlin et al, 2010;Ayón-Parente & Hendrickx, 2012;Komai et al, 2013Komai et al, , 2015Komai & Rahayu, 2014;Muñoz et al, 2014;Lima & Lemaitre, 2016). In Korea, the following 28 species of Pagurus have been reported: P. angustus (Stimpson, 1858), P. brachiomastus (Thallwitz, 1892), P. conformis De Haan, 1849, P. constans (Stimpson, 1858), P. decimbranchiae Komai & Osawa, 2001, P. exiguus (Melin, 1939, P. filholi (de Man, 1887), P. gracilipes (Stimpson, 1858), P. imaii (Yokoya, 1939), P. japonicus (Stimpson, 1858), P. lanuginosus De Haan, 1849, P. maculosus Komai & Imafuku, 1996, P. middendorffi Brandt, 1851, P. minutus Hess, 1865, P. nigrivittatus Komai, 2003, P. nigrofascia Komai, 1996, P. nipponensis (Yokoya, 1933, P. ochotensis Brandt, 1851, P. parvispina Komai, 1997, P. pectinatus (Stimpson, 1858), P. proximus Komai, 2000, P. rathbuni (Benedict, 1892, P. rubrior Komai, 2003, P. similis (Ortmann, 1892, P. simulans Komai, 2000, P. spina Komai, 1994 trigonocheirus (Stimpson, 1858), and P. undosus (Benedict, 1892) (Kamita, 1954(Kamita, , 1955Kim, 1963…”

Population and reproductive characteristics of the hermit crabPagurus proximusKomai, 2000 (Decapoda: Anomura: Paguridae) in the northern part of the species range

“…The validity of this species was supported by the study of its larval development (Kornienko & Korn, 2006). Pagurus proximus is found from the intertidal zone to a depth of 155 m at the coast of Japan from Hokkaido to Honshu and along the mainland coast from Korea to Peter the Great Bay (Komai et al , 2015). It was also encountered in Vostok Bay where the environmental conditions and the composition of inhabitants are characteristic of a large Peter the Great Bay (Figure 1).…”