Deep-Sea Phylogeographic Structure Shaped by Paleoenvironmental Changes and Ongoing Ocean Currents Around the Sea of Japan in a Crangonid Shrimp, Argis lar.

The deep-sea crangonid shrimp, Argis lar, is a highly abundant species from the northern Pacific Ocean. We investigated its phylogeographic and demographic structure across the species' extensive range, using mitochondrial DNA sequence variation to evaluate the impact of deep-sea paleoenvironmental dynamics in the Sea of Japan on population histories. The haplotype network detected three distinct lineages with allopatric isolation, which roughly corresponded to the Sea of Japan (Lineage A), the northwestern Pacific off the Japanese Archipelago (Lineage B), and the Bering Sea/Gulf of Alaska (Lineage C). Lineage A showed relatively low haplotype and nucleotide diversity, a significantly negative value of Tajima's D, and a star-shaped network, suggesting that anoxic bottom-water in the Sea of Japan over the last glacial period may have brought about a reduction in the Sea of Japan population. Furthermore, unexpectedly, the distributions of Lineage A and B were closely related to the pathways of the two ocean currents, especially along the Sanriku Coast. This result indicated that A. lar could disperse across shallow straits through the ocean current, despite their deep-sea adult habitat. Bayesian inference of divergence time revealed that A. lar separated into three lineages approximately 1 million years before present (BP) in the Pleistocene, and then had been influenced by deep-sea paleoenvironmental change in the Sea of Japan during the last glacial period, followed by a more recent larval dispersal with the ocean current since ca. 6 kilo years BP.

A new species of Fageapseudes (Crustacea: Peracarida: Tanaidacea) from California, with comments on the systematics of the family Apseudidae.

Examination of material housed at the Los Angeles County Museum of Natural History revealed a new species of Fageapseudes from 4100 m depth off California, the first record of the genus in the eastern North Pacific. Fageapseudes pluma n. sp. is very similar to the Japanese species Fageapseudes brachyomos Bamber, but can be distinguished by differences in setation and by having fewer articles in the antennal flagellum and uropodal exopodite. It is unique for the genus and subfamily in having the inner caudodistal seta of the maxillipedal endite "feather-like" instead of "leaf-like" or simply setulose. Problems with the current classification of the Apseudidae are briefly discussed, and new diagnoses are established for the subfamily Leviapseudinae and the genus Fageapseudes.

Mexctenapseudes boeschi, a new tanaidacean genus and species (Crustacea: Peracarida: Apseudomorpha: Parapseudidae) from the Mexican coast of Campeche with the designation of a new related Australian genus to receive Longiflagrum caeruleus (Boesch, 1973).

Two new genera of parapseudid Tanaidacea belonging to the Discapseudes-Halmyrapseudes Complex sensu Heard et al. (=Complex) are designated from Mexican and Australian waters. Mexctenapseudes boeschi n. gen., n. sp. is described from Campeche Mexico and Pseudolongiflagrum n. gen. is designated from Australia. The new Mexican genus displays similarities to the West Pacific and Indian Ocean genera Ctenapseudes Bamber, Ariyananda Silva, 1997 and Longiflagrum Guu, 1995. The new related genus, Pseudolongiflagrum, having affinities with Ctenapseudes and Mexctenapseudes n. gen., is designated to receive Longiflagrum caeruleus (Boesch) known from Australia. A key to the genera within the parapseudid subfamily Parapseudinae Guu is presented and possible factors concerning the ecology, origins, and distribution of the members of the Complex considered.

A new genus and species of Apseudidae, and a new species of Bunakenia (Crustacea: Tanaidacea: Apseudomorpha) from the Northwest Atlantic and Gulf of Mexico.

Examination of material from the Campeche region of the southern Gulf of Mexico revealed the presence of a new genus and species of Apseudidae that appears to be transitional between Bunakenia Guu and Apseudes Leach sensu lato. This new taxon, Pseudobunakenia anablesis n. gen., n. sp. is found throughout the Gulf of Mexico (GOM) and Northwest Atlantic as far north as South Carolina. It is known in the literature under the designation Apseudes spinosa Sars sensu Dawson and Apseudes sp. A (Heard et al.). Also, Bunakenia hamata n. sp. is described from offshore Georgia and is distributed from the Florida Gulf Coast and the Northwest Atlantic as far north as South Carolina. It is known in the literature under the designation Bunakenia sp. A (Heard et al.) and is the only known species of that genus in the GOM/NW Atlantic. It can be distinguished from its congeners by a combination of characters such as the pereonites having posterolateral apophyses, the antennule first peduncle article denticulate, the antennule accessory flagellum having five articles, and the first pereopod having four ventral propodal spiniform setae. A key to the known species is presented.

A new species of the Hyalella 'azteca' complex (Crustacea: Amphipoda: Hyalellidae) from Florida.

Examination of material from the Wakulla River in north-western Florida revealed the presence of a new species of the amphipod genus Hyalella. It appears to be most closely related to H. azteca (Saussure) sens. strict., but can be distinguished by the nature of maxilla 1 and the telson. The setation of uropod 3 has been given systematic importance for this genus, but we show in the present paper that this character exhibits high intraspecific variation, even within the same individual. This is the first formally described species of Hyalella from Florida.

Two new species of Cerapus (Crustacea: Amphipoda: Ischyroceridae) from the Northwest Atlantic and Gulf of Mexico.

Examination of material from the Northwest Atlantic and Gulf of Mexico revealed the presence of two new species of the amphipod genus Cerapus. One of the species occurs in the NW Atlantic (Delaware Bay and Great South Bay, New York) and the other species occurs in the Gulf of Mexico (Manatee River, Florida and Corpus Christie Bay, Texas). They can be distinguished from congeners by a combination of characters: number of antennular flagella articles, position of the male gnathopod 2 carpal process, shape of the inner ramus of pleopod 2, presence of a distoventral hook on the uropod 1 peduncle of the male, and the nature of the pereopod 7 spination/setation. They can be distinguished from each other by the number of antennular flagella articles in the female and in overall body size.

Systematic and taxonomic observations on the subfamily Synapseudinae Gutu, 1972 and related metapseudid taxa (Crustacea: Tanaidacea: Apseudomorpha), with the erection of a new genus and descriptions of three new species.

The tanaidacean metapseudid subfamily Synapseudinae Gutu is reviewed, partially revised and the type species, Synapseudes minutus Miller, redescribed. As rediagnosed and defined here, the Synapseudinae is restricted to the genera Synapseudes Miller, Vicinisyndes Gutu, and Creefs Stepien Blazewicz-Paszkowycz. The genera Curtipleon Bacescu and Cryptapseudes Bacescu are excluded from this subfamily. Three new species, S. caleyi, S. singularis, and S. hansknechti are described, bringing the number of putative species within the genus to 26. An identification key and table of selected specific characters for the species of Synapseudes are provided. A new monotypic genus, Ronabus, which is placed within the subfamily Metapseudinae Lang, is erected to receive Synapseudes idios Gardiner. The present taxonomic status of subfamilies within the Metapseudidae is briefly assessed.

New deep-sea Paratanaoidea (Crustacea: Peracarida: Tanaidacea) from the northeastern Gulf of Mexico.

One new genus is erected and four new species of paratanaoidean tanaidaceans are described from deep waters in the northeastern Gulf of Mexico: one in each of the genera Collettea, Tanaella, and Pseudomacrinella, and one as a new genus in the family Anarthruridae. Keys to species in the genera Collettea, Tanaella, and the genera of the Anarthruridae are provided.