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Kondo M.,University of Ryukyus | Maeda K.,Okinawa Institute of Science and Technology | Hirashima K.,Wakayama Prefectural Museum of Natural History | Tachihara K.,University of Ryukyus
Marine and Freshwater Research | Year: 2013

Eggs and larvae of three amphidromous species of Rhinogobius goby (Rhinogobius brunneus, Rhinogobius sp. MO and Rhinogobius sp. CB) from Okinawa Island, Japan, were reared under uniform conditions to describe and compare their larval development. Although the larval morphologies of the three species were very similar, some differences were observed in the timing of ontogenetic events among them. R. brunneus had the largest yolk and saved it for a longer period of time, whereas Rhinogobius sp. MO had the smallest yolk, which was exhausted earlier. The period until yolk exhaustion is thought to restrict the distance that migrating larvae can drift, which determines the specific adult distribution. Each of these two amphidromous species are close relatives of different fluvial resident species. Evolution of the fluvial residents could be explained by different scenarios based on the larval traits of R. brunneus and Rhinogobius sp. MO. Rhinogobius sp. CB hatched at a smaller size and grew slower than the other two species. No fluvial species have derived from Rhinogobius sp. CB. One possible explanation is that the smaller and slower-growing larvae of Rhinogobius sp. CB find it more difficult to remain within streams. © CSIRO 2013. Source


Misaki A.,Kitakyushu Museum of Natural History and Human History | Ohara M.,Wakayama Prefectural Museum of Natural History
Paleontological Research | Year: 2011

Late Cretaceous heteromorph ammonoids, Ainoceras kamuy and Ainoceras paucicostatum, were discovered for the first time from the Futakawa Formation in the Aridagawa area, Wakayama, southwestern Japan. Other molluscan fossils such as Eupachydiscus sp., Gaudryceras aff. striatum, "Gigantocapulus" transformis, Sphenoceramus nagaoi, Sphenoceramus orientalis and Inoceramus balticus also cooccur with Ainoceras, and together they indicate the lower Campanian Stage. Recently, the middle TuronianSantonian and upper lower CampanianMaastrichtian litho- and biostratigraphy in the Aridagawa area was established. Therefore, the lower Campanian strata in the study area fill the gap between them and supplement the Upper Cretaceous stratigraphy in the Aridagawa area. The results of this study advance the biostratigraphy and correlation of the marine Cretaceous strata in the northwestern Pacific region. © 2011 by the Palaeontological Society of Japan. Source


Kishi M.,Japanese Apricot Laboratory | Matsuno S.,Wakayama Prefectural Museum of Natural History
Japanese Journal of Applied Entomology and Zoology | Year: 2015

The sex of adults of Phenolia (Lasiodites) picta (MacLeay) is distinguished by the morphology of the pygidium and the presence of a well sclerotized tergite VIII in males. These differences are visible under a binocular microscope at a low magnification (15×). As the difference between the sexes can be distinguished without killing specimens, it can be used to observe the specific behaviors of females and males and in ecological research. Source


Yamana Y.,Wakayama Prefectural Museum of Natural History | Kohtsuka H.,University of Tokyo
Plankton and Benthos Research | Year: 2016

The cucumariid sea cucumber Plesiocolochirus inornatus (Marenzeller, 1881) was rediscovered in shallow water of the Pacific Ocean, on the south coast of Fukushima Prefecture, eastern Japan. The last report of this species in Japanese waters was published a hundred years ago, although this species possibly has a wide distribution in Japanese waters. Since there is no detailed information on its external appearance, we prepared images of the body shape on the basis of six new specimens. The body of P. inornatus has obviously distinguishable dorsal and ventral sides in the living state with tapered ends that turn upwards, mid-body of the ventral side extremely flattened and nearly half-round in cross-section, dorsal surface smooth with retracted minute ambulacral-papillae scattered uniformly regardless of radii or inter-radii. Furthermore, detailed images of ossicle shape and calcareous ring shape were prepared. © The Japanese Association of Benthology. Source


Shigeta Y.,National Museum of Nature and Science | Misaki A.,Kitakyushu Museum of Natural History and Human History | Ohara M.,Wakayama Prefectural Museum of Natural History
Paleontological Research | Year: 2012

Discovery of Gaudryceras tombetsense Matsumoto, 1984 in the Futakawa Formation of the Sotoizumi Group in the Aridagawa area, Wakayama, southwestern Japan establishes that this formation includes sediments of early Late Maastrichtian age, which is the youngest record of the Sotoizumi Group distributed in Shikoku and the Kii Peninsula. The occurrence of the youngest fossils from the easternmost area of the Sotoizumi Group may support the suggestion that the depocenter of the Sotoizumi basin migrated eastward due to movement along the Kurosegawa Tectonic Zone (KTZ), which was still active during Campanian to Maastrichtian time. © 2012 by the Palaeontological Society of Japan. Source

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