First Zoea of a Rare Deep-sea Shrimp Vexillipar repandum Chace, 1988 (Crustacea, Decapoda, Caridea, Alpheidae), with Special Reference to Larval Characters of the Family

First zoea of a rare alpheid shrimp Vexillipar repandum Chace, associated with a deep-sea hexactinellid sponge, is described and illustrated based on laboratory-hatched material. The general morphology of the first zoea of V. repandum is similar to those of the previously-known examples of Alpheus. A diagrammatic key for identification of the family among caridean zoeas is proposed

Genetic Isolation between the Western and Eastern Pacific Populations of Pronghorn Spiny Lobster Panulirus penicillatus

The pronghorn spiny lobster, Panulirus penicillatus, is a circumtropical species which has the widest global distribution among all the species of spiny lobster, ranging throughout the entire Indo-Pacific region. Partial nucleotide sequences of mitochondrial DNA COI (1,142–1,207 bp) and 16S rDNA (535–546 bp) regions were determined for adult and phyllosoma larval samples collected from the Eastern Pacific (EP)(Galápagos Islands and its adjacent water), Central Pacific (CP)(Hawaii and Tuamotu) and the Western Pacific (WP)(Japan, Indonesia, Fiji, New Caledonia and Australia). Phylogenetic analyses revealed two distinct large clades corresponding to the geographic origin of samples (EP and CP+WP). No haplotype was shared between the two regional samples, and average nucleotide sequence divergence (Kimura's two parameter distance) between EP and CP+WP samples was 3.8±0.5% for COI and 1.0±0.4% for 16S rDNA, both of which were much larger than those within samples. The present results indicate that the Pacific population of the pronghorn spiny lobster is subdivided into two distinct populations (Eastern Pacific and Central to Western Pacific), with no gene flow between them. Although the pronghorn spiny lobster have long-lived teleplanic larvae, the vast expanse of Pacific Ocean with no islands and no shallow substrate which is known as the East Pacific Barrier appears to have isolated these two populations for a long time (c.a. 1MY)

Larval Development of the Spiny Sand Crab Lophomastix japonica (Durufle, 1889) (Crustacea, Anomura, Albuneidae) under Laboratory Conditions

The complete larval development of Lophomastixjaponica (Durufle, 1889), a spiny sand crab from Hokkaido, northern Japan, is described and illustrated on the basis oflaboratory-reared material. The present species passes through three zoeal and one megalopal stages; zoeas moulted to megalopa 30-35 days after hatching, at water temperature of l8°C and salinity of 30 ppt. The carapace of the megalopa exhibits diagnostic features which allow distinction among Japanese albuneid genera. Zoeal characters of L. japonica are compared with those of other albuneid species. Morphological remarks on albuneid megalopas are also given

LARVAL DEVELOPMENT IN LABORATORY OF CANCER AMPHIOETUS RATHBUN, IN COMPARISON WITH THOSE OF SEVEN OTHER SPECIES OF CANCER (DECAPODA, BRACHYURA)

Recently the larval development has been described in detail successively in the following seven species of Cancer (Decapoda, Brachyura): Cancer magister Dana, C. productus Randall, C. gracilis Dana, C. antennarius Stimpson and C. anthonyi Rathbun from the Pacific coast of North America and C. irroratus Say and C. borealis Stimpson from the Atlantic coast of North America (Poole, 1966; Trask, 1970; Ally, 1975; Roesijadi, 1976; Sastry, 1977a, b; Anderson, 1978). Cancer amphioetus Rathbun used for the present study is a dweller on the Pacific coast of Hokkaido, North Japan. The first zoea of this species has been observed already under laboratory conditions (Iwata, 1973). In the present study, the complete larval development including five zoeal stages and a megalopa are described in detail and the larval characters in the present species are compared with those in seven Cancer species hitherto reported

A New Species of the Commensal Crab Genus Aphanodactylus (Crustacea : Brachyura : Pinnotheridae) from the Yaeyama Islands, Southern Japan

A new commensal crab, Aphanodactylus loimiae, is described from the Yaeyama Islands, Okinawa Prefecture, Japan. The present species is the third species of this rare pinnotherid genus. It differs from the two previously known species in carapace shape, number of segments of anntennal flagellum, and number of merus teeth on walking legs. The single specimen was found in the tube of a sessile polychaete, Loimia ingens Grube. A dichotomous key and a diagrammatic key to the subfamilies of the Pinnotheridae and the genera of the Asthenognathinae in Japan are given

Pagurus imafukui, a New Species of Deep-water Hermit Crab (Crustacea : Anomura : Paguridae), with Notes on its Larvas

A new species of the hermit crab genus Pagurus was collected from depths of 126 and 300 meters off the Pacific coast of Japan. This is a strongly polymorphic species, which has been found only in shells of scaphopods (Order Dentalioida). Pagurus imafukui new species is described, illustrated and its morphological variations discussed. Aspects of early larval morphology of this species are also given