The earliest fossil record of the genus Pseudotsuga (Pinaceae) in Asia, Pseudotsuga tanaii Huzioka, was reexamined with additional materials of seeds, leaves, cones, and twigs from the earliest Miocene Shichiku Flora of the Joban area, northeast Japan. These specimens were restudied to better understand the relationship of these fossils with the extant and fossil species from Asia. Pseudotsuga tanaii not only shows characters common to the modern species in East Asia, but also yields similar characters seen in the American clade. Thus, it could be an ancestral taxon of the Asian clade, which appeared before the diversification of the East Asian species. In contrast to the extant Pseudotsuga species growing under warm-temperate climate conditions at middle to high elevations in the mountains, Pseudotsuga tanaii appears to have been associated with lowland vegetation growing at lake margins. Forest vegetation associated with the species is equivalent to the Mixed Northern Hardwood forest, which develops under cooler climatic conditions. The inferred habitat of Pseudotsuga tanaii and its age support the hypothesis based on molecular phylogeny and morphological analyses that the genus originated in the higher latitudes during the early Paleogene and migrated south following the climatic deterioration during the late Paleogene.

We document the occurrence of three species of Jurassic crinoids from the Lower Jurassic Toyora Group (Yamaguchi Prefecture), western Japan, belonging to the genera Pentacrinites and Seirocrinus. The former is found for the first time in Japan. This find extends the range of Pentacrinites into Eastern Eurasia. These species can be confidently assigned to Pentacrinites dichotomus (McCoy, 1848), P. cf. doreckae Simms (1989), and Seirocrinus subangularis (Miller, 1821). Pentacrinites and Seirocrinus are well known genera in the Lower Jurassic of Europe, with identical species occurring in the British Lias of Yorkshire and the Posidonienschiefer of southern Germany. Furthermore, previous studies have established that the taphonomy, sedimentology and palaeoenvironmental context of the Toyora Group, at least in the Nishinakayama Formation, are comparable to those of the European Boreal and Tethyan shallow seas including the occurrence of oxygen-depleted bottom conditions. Thus, the paraautochthonous preservation and wide geographic range of these species, as well as the associated fauna, suggest a possible pseudoplanktonic lifestyle for both Pentacrinites and Seirocrinus in the Early Jurassic of Japan. The ‘Hiemer’ specimen kept in the University of Göttingen is designated herein as the neotype of Seirocrinus subangularis.

A new crinoid species of the family Hemicrinidae Rasmussen sensu Rasmussen (or Sclerocrinidae Jaekel sensu Hess), Hemicrinus klikushini sp. nov., is described from the Danian (early Palaeogene) of the Middle Vistula River valley in eastern Poland. It is characterized by a low cup of five narrow radials, two of which are larger and elongated. This cup is attached to an elongate proximal columnal. To date, the present find constitutes the youngest record of this genus and documents the presence of cyrtocrinid crinoids in a shallow-water environment. The systematic research of Cretaceous Hemicrinus species is reviewed.

An ophiuroid faunule, consisting of several articulated discs and numerous semiarticulated arm fragments, from the early Anisian (Middle Triassic) Waruishi Formation, Yakuno Group, in Kyoto Prefecture, central Japan, is described as Aplocoma sp. Insufficient preservation, in part due to incipient disintegration of the ophiuroid skeleton prior to burial, precludes a meaningful taxonomic interpretation at the species level. The Waruishi specimens represent the first Middle Triassic extra-Paleotethyan record of the genus Aplocoma and the oldest brittle-star body fossils from Japan to be described in detail.

No previous studies have investigated changes in the offshore molluscan assemblages of the Japan Sea during the last deglacial period. We examined the sedimentary facies and the stratigraphic distribution of molluscs in cored sediments collected at 132 m water depth off Sado Island, Japan. The ages of 13 specimens of molluscan shells were determined by ¹⁴C dating. Moreover, we analyzed the relative abundance of the planktonic foraminifer Globigerinoides ruber, which is a proxy of the Tsushima Current. The results show that the cored sediments were deposited from 13,574 ± 121 cal yr BP at a water depth that increased over time from about 50 m to 132 m. Three sedimentary facies are recognized in the cored sediment, in ascending stratigraphic order; coquina sediments, massive silt, and massive fine sand yielding many molluscan shells. The change in substrate was caused mainly by variability in the input of terrigenous deposits at 10,640–9,300 cal yr BP (the transition from coquina to silt) and at 8,860–5,180 cal yr BP (the transition from silt to sand).¹⁴C data show that the molluscan species Porterius dalli, Cyclocardia ferruginea, Tridonta alaskensis and Puncturella nobilis were living in the Japan Sea before the initial inflow of the Tsushima Current at 9,300 cal yr BP. The modern molluscan fauna in the study area, which is dominated by Limopsis belcheri and Crenulilimopsis oblonga, may have become established by at least 5,180 cal yr BP.

We describe the tooth of a fossil beaver (Castoridae, Rodentia) discovered in the lower Miocene Koura Formation of Shimane Prefecture, western Japan. The specimen is an isolated, unworn left lower third molar that can be assigned to a large castorid, Youngofiber. To determine the taxonomic classification based on the internal enamel patterns of the tooth, we reconstructed those patterns using a three-dimensional image by X-ray peripheral quantitative computed tomography (pQCT). The obtained enamel patterns indicate that the M₃ of Youngofiber is characterized by a transversely elongated proparafossettid and simple synclinids running obliquely and parallel. Moreover, the present specimen retains a well developed mesostriid extending up to half the lingual height of the crown. This characteristic is shared with another castorid specimen from the lower Miocene Nojima Group in Nagasaki Prefecture, suggesting a close relationship between Koura and Nojima beavers.