Hiroyuki Tachikawa

Novel organization of the mitochondrial genome in the deep-sea coral, Madrepora oculata (Hexacorallia, Scleractinia, Oculinidae) and its taxonomic implications

Madrepora is one of the most ecologically important genera of reef-building scleractinians in the deep sea, occurring from tropical to high-latitude regions. Despite this, the taxonomic affinities and relationships within the genus Madrepora remain unclear. To clarify these issues, we sequenced the mitochondrial (mt) genome of the most widespread Madrepora species, M. oculata, and compared this with data for other scleractinians. The architecture of the M. oculata mt genome was very similar to that of other scleractinians, except for a novel gene rearrangement affecting only cox2 and cox3. This pattern of gene organization was common to four geographically distinct M. oculata individuals as well as the congeneric species M. minutiseptum, but was not shared by other genera that are closely related on the basis of cox1 sequence analysis nor other oculinids, suggesting that it might be unique to Madrepora.

A NEW HERMIT CRAB OF THE GENUS CALCINUS FROM MICRONESIA, INCLUDING NEW INFORMATION ON C. REVI (DECAPODA: ANOMURA: DIOGENIDAE)

Calcinus kurozumii, new species, is described and illustrated based on specimens from the northern Mariana Islands, Micronesia. It is a member of the group in which the dactyls and propodi of the third pereiopods have dense brush-like setae on the ventral face. The new species is distinguished from other Indo-West Pacific species of the group by the armature of the left cheliped. The new species is compared with a similar species from Polynesia, C. revi Poupin and McLaughlin, 1998. Calcinus revi is rediagnosed based on new material from the Izu-Ogasawara-Mariana Arc, and growth-related morphological variations and color are reported. A key to the Indo-West Pacific species of Calcinus with the brush of setae is provided.

Diogenes holthuisi, a new species of hermit crab (Decapoda, Anomura, Diogenidae) from shallow waters of the Ogasawara (Bonin) Islands, Japan

This chapter describes and illustrates Diogenes holthuisi , a new species of hermit crab from shallow waters of the Ogasawara (Bonin) Islands, Japan. The new species is characterized by the bifid shaped antennal acicles and presence of a few very strong spines posterior to the spine row on the branchiostegite. By these characters, the new species is easily distinguished from other species among the species group of Diogenes with a simple intercalary rostral process and the antennal peduncles longer than the ocular peduncles. The systematics of the new species is also discussed in detail. Keywords: Diogenes holthuisi ; hermit crab; Japan; Ogasawara Islands; shallow waters; systematics

BONINPAGURUS ACANTHOCHELES, A NEW GENUS AND SPECIES OF HERMIT CRAB (DECAPODA: ANOMURA: PAGURIDAE) FROM SHALLOW WATERS OF THE OGASAWARA (BONIN) ISLANDS, JAPAN

Abstract Boninpagurus acanthocheles, a new genus and new species of hermit crab (Decapoda: Anomura: Paguridae) from shallow waters of the Ogasawara (Bonin) Islands, Japan, is described and illustrated. The new genus is characterized by the following characters: in males, the coxa of the right fifth pereopod has a straight or slightly curved, elongate sexual tube that is about 2–3 times the coxal length, directed laterally or posterolaterally, the proximal portion of the tube being stout and opaque and the distal portion transparent; the coxa of the left fifth pereopod has a short protrusion of vas deferens; females have paired gonopores and lack first pleopods. The new genus is similar to Anapagrides in several diagnostic features, from which it is distinguished by morphology of the male sexual tubes, the fourth pereopods, and female gonopores.

Crabs of the families Palicidae and Crossotonotidae (Crustacea, Decapoda, Brachyura, Palicoidea) from the Ogasawara Islands, Japan, with the description of a new species.

Four species of palicoid crabs, Neopalicus jukesii (White, 1847) and Rectopalicus ampullatus Castro, 2000 of the family Palicidae, and Crossotonotus spinipes (De Man, 1888) and a new species of Pleurophricus A. Milne-Edwards, 1873 of the family Crossotonotidae, are recorded from the Ogasawara Islands, Japan. Diagnostics for the new species are the protruded bilobed front, six subacute lobate teeth at each lateral margin of the carapace, six rounded lobes at the posterior margin of the carapace, a crested armature of the cheliped carpus, and the strongly depressed ambulatory legs, which readily distinguish it from its two congeners, P. cristatipes A. Milne-Edwards, 1873 known by two males from Australia and the Kai Islands in Indonesia, and P. longirostris (Moosa & Serène, 1981) known by a female from the Sunda Strait, Indonesia.