Gaudryceras hobetsense sp. nov. is described from the Nostoceras hetonaiense Zone (= lowest Maastrichtian) of the Hobetsu area, south-central Hokkaido, Northern Japan. Its shell is characterized by fine lirae on early whorls, distant rounded or flat-topped, narrow band-like ribs on middle and later whorls, and frequent collar-like ribs on later whorls. The occurrence of this new species strongly suggests the presence of lowest Maastrichtian strata in southern Alaska, and sheds light on the age delineation of the chronologically poorly defined beds in northern and eastern Hokkaido.

Two ammonoids of the subfamily Gabbioceratinae, Obataceras manjiense gen. et sp. nov. and Tanabeceras pombetsense gen. et sp. nov., are described from the Upper Albian of Hokkaido, Japan. The Gabbioceratinae evolved and radiated mainly in the Mediterranean area during Late Aptian to Middle Albian times, but thereafter disappeared from the region. The occurrences of Gabbioceratinae in Hokkaido suggest that their geographical distribution was extended to the Northwest Pacific before the Late Albian, where they then flourished from Late Albian to Cenomanian time.

We review the entelodontid artiodactyl fauna of the upper Eocene Ergilin Dzo Formation in southeastern Mongolia. Also, we describe new specimens of Brachyhyops trofimovi from the Khoer Dzan locality and review the characteristics and Asian distribution of Brachyhyops. The revised entelodontid fauna of the formation consists of three species: Entelodon gobiensis (from the Khoer Dzan and Ergilin Dzo localities), Brachyhyops trofimovi (from the Khoer Dzan locality), and Brachyhyops? sp. (from the Ergilin Dzo locality). The discovery of p4 and M2 of B. trofimovi demonstrates the definitive diagnostic characteristics of this species within the genus: p4 is buccolingually wide and is triangular in occlusal view; it has a well developed and high cusp (= hypoconid?), which is fused to the posterior part of the protoconid; and M2 has a better-developed pericone. In Asia, Brachyhyops is recorded only in the southern part during the middle Eocene and only in the northern part during the late Eocene, implying that the genus originated in the southern part of Asia and subsequently migrated northward, giving rise to northern Asian and North American Brachyhyops.

The Tetori Group (Middle Jurassic to Lower Cretaceous) exposed in the Shokawa area of Gifu Prefecture, Japan, is known as a terrestrial vertebrate fossil site. This area has yielded over 1000 microvertebrates, including choristoderes, Shokawa ikoi (Evans and Manabe, 1999a; Matsumoto et al., 2002); a lizard, Sakurasaurus shokawensis (Evans and Manabe, 1999b); theropod teeth; iguanodontian teeth (Hasegawa et al., 1995); a pterosaur (Unwin et al., 1996); and fishes and turtles (e.g., Evans et al., 1998). Vertebrate remains have also been reported from other Tetori Group sites in the Fukui, Ishikawa, and Toyama prefectures (e.g., Manabe et al., 2000; Kobayashi and Azuma, 2003). Ornithischian dinosaurs are common from these sites: iguanodontian dinosaurs, including Fukuisaurus tetoriensis, from the Kitadani Formation, Fukui Prefecture (Kobayashi and Azuma, 2003; Shibata, 2009); a partial skull of the cerapod dinosaur Albalophosaurus yamaguchiorum; and iguanodontian teeth from the Kuwajima Formation, Ishikawa Prefecture (e.g., Ohashi and Barrett, 2009). In 1988, an isolated dinosaur tooth (SBEG 007) was found from a float matrix that was considered to come from an outcrop of the Okurodani Formation exposed along the Ogamigo River in the Shokawa area of Takayama City, Gifu Prefecture, central Japan (Hasegawa et al., 1990). SBEG 007 was tentatively identified as a hypsilophodontid dinosaur because of the presence of a cingulum (Hasegawa et al., 1990). According to recent studies (e.g., Butler et al., 2008), this feature is not diagnostic of hypsilophodonts, but is a synapomorphy of Ornithischia (Parker et al., 2005). This study demonstrates that SBEG 007 represents an unidentified ornithischian that differs from other ornithischian dinosaurs previously reported in the Tetori Group. SBEG 007 suggests that the ornithischian dinosaurs of the Tetori Group are more diverse than previously thought.

This study describes a brachiopod fauna, consisting of 12 species in 10 genera, from the Upper Permian (Wuchiapingian) Otori Formation of Okutadami, Joetsu Belt, Central Japan. The fauna includes a new species, Kochiproductus okutadamiensis. The Okutadami fauna, a Boreal fauna lacking Tethyan or Panthalassan elements, is the northernmost fauna of the Japanese Permian. Palaeobiogeographical data derived from the Okutadami fauna suggest that Okutadami was located at the northernmost area of Proto-Japan in the Late Permian. This conclusion supports a strike-slip tectonic model that describes large-scale sinistral strike-slip movement along the Tanakura Tectonic Line (TTL)-Median Tectonic Line (MTL) from the late Early Cretaceous to Palaeogene.

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.

Abstract. 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.

The early Pleistocene ostracod fauna from the Hamada Formation (ca. 1.5–1.2 Ma) was investigated in the Shimokita Peninsula, northeastern Japan. Twelve samples of this fossil fauna yielded 184 species, many of which are representative upper-shelf ostracods in the modern northeastern Japan Sea. Three biofacies were defined by Q-mode cluster analysis. The two most abundant species for each biofacies are Neonesidea sp. and Schizocythere kishinouyei in biofacies N, Buntonia hanaii and Yezocythere hayashii in biofacies B, and Laperousecythere robusta and Finmarchinella daishakaensis in biofacies L. The depositional environment of the individual biofacies can be defined as (1) upper-shelf area under open-sea influence in relatively high salinity (biofacies N), (2) inner—central-bay area, with relatively low salinity (biofacies B), and (3) bay-mouth area with intermediate salinity levels between those of (1) and (2) (biofacies L). Water depth decreased from the upper-shelf area through to the bay-mouth and then to the inner-central-bay areas during the depositional period of the studied horizons. The palaeoceanographic setting during most of the depositional period was estimated as the conditions of a water mass similar to the present Japan Sea Central Water, while surface waters were influenced by currents similar to the modern Tsugaru Warm and Oyashio Cold Currents. Based on the species content of biofacies B, Buntonia and Yezocythere commonly inhabited shallow inner-bay areas around 1.2 Ma in this region, instead of the modern representative inner-bay taxa of Japan which first appeared in the northernmost Honshu region after 1.0 Ma. The occurrence mode for extant and now-extinct species of the families Hemicytheridae, Cytheruridae and Eucytheridae suggests that the ostracod fauna in the upper-shelf environment from the Hamada Formation was similar to those from the southwestern to northeastern Japan Sea coast during the same period, even though it is situated at the easternmost extremity of the Japan Sea coastline (ca. 141°E) near the Pacific.

Based on materials from the Krasnoyarka Formation in the Naiba area in south Sakhalin, Russia, taphonomic histories of a large Campanian ammonoid, Canadoceras kossmati Matsumoto, 1954, were closely investigated. Large Canadoceras shells exceeding 30 cm in diameter are usually embedded horizontally and solitarily in muddy sandstone. Athin, lenticular calcareous concretion envelopes the shell (=envelope concretion). Their body chambers are mostly lost. The inner whorls comprising the center of the umbilicus completely disappear without exception, and only two or three outer whorls are preserved. The body and air chambers are somewhat compressed by compaction and are filled with sediments. Phycosiphon burrows are common not only in open body chambers but also in inner air chambers, which were originally closed. These observations suggest that the thin-shelled inner whorls and organic-rich siphuncular tubes degraded before final burial of the shell, and sediment infilling to the inside of the chambers followed. The early loss of inner whorls and siphuncular tubes gave rise to “draft-through currents.” The continuous supply of oxygen and nutrients by the draft-through currents supported the Phycosiphon producers in the inner air chambers. Compared with other calcareous concretions containing intact fossils, values of minus-cement porosity (MCP) remain relatively low (63–74%) and vary by areas even in the same envelope concretion. This indicates that the envelope concretions were cemented under a progressive increase of compaction during the later diagenetic stage. The formation of the envelope concretion appears to be a long-term phenomenon. Various events at different stages have been overprinted in a single large ammonoid fossil.