LAOMENES HOLTHUISI SP. NOV., A NEW OF -ASSOCIATED PONTONIINE SHRIMP (DECAPODA, CARIDEA, PALAEMONIDAE) FROM THE IZU ISLANDS, JAPAN, WITH SOME REMARKS ON JAPANESE SPECIES OF THE LAOMENES CLARK, 1915

BY

IVAN MARIN1,3) and JUNJI OKUNO2,4) 1) A. N. Severtzov Institute of Ecology and Evolution of RAS, Moscow, Russia 2) Coastal Branch of Natural History Museum and Institute, Chiba, 123 Yoshio, Katsuura, Chiba, 299-5242 Japan

ABSTRACT

A new species of crinoid-associated pontoniine shrimp genus from the genus Laomenes Clark, 1915, L. holthuisi sp. nov., is described from Hachijo Island, Izu Islands, Japan. The speciesispartoftheL. amboinensis species group, differing from the other species by its morphology and coloration. Specimens previously recorded from Japan as L. ceratophthalmus (Borradaile, 1915) by Okuno & Fujita (2007) were examined and re-identified as L. tigris Marin, 2009.

RÉSUMÉ

Une nouvelle espèce de crevette Pontoniinae associée aux crinoïdes et appartenant au genre Laomenes Clark, 1915, L. holthuisi sp. nov., est décrite de l’île Hachijo (archipel des îles Izu), Japon. L’espèce qui fait partie du groupe d’espèces amboinensis se distingue des autres espèces par sa morphologie et sa coloration. Des spécimens précédemment signalés du Japon comme L. ceratophthalmus (Borradaile, 1915) par Okuno & Fujita (2007) ont été examinés et ré-identifiés comme L. tigris Marin, 2009.

INTRODUCTION Symbiotic communities associated with feather stars () (Echinoder- mata: Crinoidea) are very rich including various marine invertebrates, shrimp

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© Koninklijke Brill NV, Leiden, 2010 Studies on Malacostraca: 461-472 462 CRM 014 – Fransen et al. (eds.), LIPKE BIJDELEY HOLTHUIS MEMORIAL VOLUME being among the most noticeable components of such communities. The oblig- ate crinoid-associated pontoniine shrimp genus Laomenes Clark, 1915 was re- cently revised (Marin, 2009) with species appearing to be host specific, corre- lated with a specific morphology and coloration. Eight species of the genus are presently known, all from the tropical Indo-West Pacific (Bruce, 1983, 2006; Marin, 2009), however, the true diversity of the genus is far from well known. During a visit to the Coastal Branch of the Natural History Museum and Institute (CBNHM), Chiba, Japan, the first author was able to examine a col- lection of specimens of the genus Laomenes deposited there. Selected material previously recorded from Japan by Okuno & Fujita (2007) were re-examined and re-identified; all specimens previously identified as L. ceratophthalmus (Borradaile, 1915) are re-identified as L. tigris Marin, 2009; no specimens of L. ceratophthalmus were found in the collection of CBNHM. Two spec- imens (previously identified as Laomenes amboinensis) from the Izu Islands, for which an in situ photo was published in Kato & Okuno (2001) was found to be a new species and accordingly described below. Postorbital carapace length (pcl, in mm) is used as the standard measurement of size. All material is de- posited in the Coastal Branch of the Natural History Museum and Institute, Chiba (CMNH), Katsuura, Japan.

SYSTEMATIC PART

Family PALAEMONIDAE Rafinesque, 1815 Laomenes Clark, 1915 Laomenes holthuisi sp. nov. (figs. 1-6) Periclimenes amboinensis. — Kato & Okuno, 2001: 32, unnumbered fig. in color. Laomenes amboinensis. — Okuno & Fujita, 2007: 117 (in part). Material examined. — Holotype. Ovigerous female, dissected (pcl 4.0 mm) (CMNH ZC 01242), Pacific Ocean, Japan, Izu Islands, Hachijo Island, Aozumi, 15 m depth, SCUBA, from crinoid identified as Comaster nobilis, leg. J. Okuno, 10 Sept. 1997. Paratype — male (pcl 2.5 mm) (CMNH-ZC 01243), same locality and host as holotype. Description. — Holotype female. Carapace swollen, smooth, with promi- nent antennal and hepatic tooth (fig. 2A, C); antennal tooth sharp and slen- der similar to hepatic tooth. Rostrum long, deep, compressed, slightly turned downwards, with four large dorsal teeth and one subapical dorsal tooth; ven- tral margin slightly convex, with single tooth situated in distal third of length