Phenotypic and Genomic Signatures of Latitudinal Local Adaptation Along With Prevailing Ocean Current in a Coastal Goby.

In the marine realm, unidirectional ocean currents often lead to high migration rates of marine organisms and, therefore, inhibit the formation of their latitudinal genetic structure. In contrast, cryptic latitudinal structures associated with local adaptation may frequently exist in widespread species generally exposed to a strong environmental heterogeneity. However, our understanding of the evolvability of locally adapted populations in open marine environments still needs to be completed.

Scyliorhinus hachijoensis, a new species of catshark from the Izu Islands, Japan (Carcharhiniformes: Scyliorhinidae).

A new species of catshark genus Scyliorhinus, S. hachijoensis sp. nov.

DNA barcoding and morphological analyses revealed validity of Diadema clarki Ikeda, 1939 (Echinodermata, Echinoidea, Diadematidae).

A long-spined sea urchin Diadema-sp reported from Japanese waters was genetically distinct from all known Diadema species, but it remained undescribed. Extensive field surveys in Japan with molecular identification performed in the present study determined five phenotypes (I to V) in Diadema-sp according to the presence and/or shape of a white streak and blue iridophore lines in the naked space of the interambulacral area. All phenotypes were distinct from Diadema setosum (Leske, 1778) and Diadema savignyi (Audouin, 1829), of which a major type (I) corresponded to Diadema clarki Ikeda, 1939 that was questioned and synonymized with Diadema setosum by Mortensen (1940).

Two species of philometrid nematodes (philometridae) from marine fishes off Japan, including Philometroides branchiostegi sp. n. from Branchiostegus japonicus (malacanthidae).

Gravid females of two species of philometrid nematodes (Philometridae) were collected from marine perciform fishes in Japanese waters, mainly from the southern Sea of Japan. Based on light microscopy and scanning electron microscopy examinations, the previously described but poorly known species Philometra cryptocentri Yamaguti, 1961 is redescribed from specimens recovered from the abdominal cavity of Acanthogobius flavimanus (Temminck et Schlegel), Pterogobius elapoides (Günther) and P. zonoleucus Jordan et Snyder (all Gobiidae) (all new host records); the number (14) and arrangement of cephalic papillae in this species are described for the first time.

Phylogeography and historical demography of the anadromous fish Leucopsarion petersii in relation to geological history and oceanography around the Japanese Archipelago.

Phylogeographical patterns of marine and diadromous organisms are often influenced by dynamic ocean histories. For example, the marine realm around the Japanese Archipelago is an interesting area for phylogeographical research because of the wide variation in the environments driven by repeated shifts in sea level in the Quaternary. We analysed mitochondrial cyt b gene and nuclear myh6 gene sequences for individuals collected from throughout the range of the anadromous fish Leucopsarion petersii to assess the lineage divergence, phylogeographical pattern and historical demography in relation to geological history and oceanographic features around the archipelago.