Middle Permian ammonoid faunas are recognized from the Hosoo and Kamiyasse Formations in the Kamiyasse-Imo district, north of Kesennuma, Southern Kitakami Massif, Northeast Japan. The faunas comprise the following genera: Parastacheoceras, Demarezites, Demarezites?, Waagenoceras, Timorites, Tauroceras?, Cardiella, Adrianites, Agathiceras, Agathiceras?, Paraceltites and Cibolites. Parastacheoceras bidentatus gen. and sp. nov. is newly proposed. The genera Demarezites, Tauroceras, Cardiella and Adrianites are described for first time from Japan. Based on these ammonoids, the middle part of the Hosoo Formation, upper part of the Hosoo Formation to the lower middle part of the Kamiyasse Formation, and upper middle part of the Kamiyasse Formation are correlatable with the Middle Permian Roadian, Wordian and Capitanian, respectively. The discovery of genera Demarezites and Cardiella strongly supports the previous hypothesis that the South Kitakami Paleoland was located in the equatorial province during the Middle Permian.

This paper records eight species of Late Triassic Tethyan bivalves from the oceanic limestone and associated basaltic volcaniclastic rocks which belong to the Sambosan accretionary complex in southwest Japan. The bivalve-bearing succession consists of basaltic volcaniclastic rocks (ca. 60 m thick) conformably succeeded by dark gray bedded limestone (ca. 10 m thick), which is, in turn, overlain by massive limestone (ca. 50 m thick). The succession is dated as Carnian to Norian by means of conodonts and bivalves. Upper Triassic bivalves, including Gruenewaldia decussata, G. woehrmanni and Costatoria goldfussi, are recorded from the examined succession. Their occurrence implies a Tethyan affinity for the examined Sambosan oceanic rocks. No bivalve species characteristic of a high latitudinal zone occurs in this succession.

Globigerinoides ruber has recently received much attention for paleoceanography in the subtropical and tropical ocean. G. ruber has two morphotypes (G. ruber s.s. and G. ruber s.l.) which dwell at the surface layer and at deeper depth in the surface water, respectively. In order to establish a proxy for the quantitative reconstruction of sea surface temperature, oxygen and carbon isotopes were analyzed in G. ruber collected at 30°N, 175°E in the Pacific. Based upon the fluxes of foraminifers and organic matter (OM), the entire duration of the sediment trap experiment was divided into two periods: Period 6A (May to December) characterized by low fluxes of organic matter and foraminifers under a stratified condition of the surface ocean, and 6B (January to April) characterized by high fluxes of OM and foraminifers under a well developed deep-mixing layer. With respect to seasonal variability, δ¹⁸O values of both G. ruber s.s. and G. ruber s.l. decreased in summer with a minimum around September–October and increased in winter and spring, which was also the case with their δ¹³C values. The mean difference of δ¹⁸O values between both morphotypes was 0.25‰ in August–October, corresponding to a 1°C difference in water temperature. Consistency with field observation confirms that G. ruber s.s. and G. ruber s.l. dwell at the surface and at 30–50 m water depth, respectively. In contrast, the difference in δ¹⁸O and δ¹³C values between the two morphotypes was not significant in early April due to deep-mixing. Together with foraminiferal assemblage, δ¹⁸O values of the two morphotypes of G. ruber can be a good proxy for quantitative reconstruction of vertical seawater temperature in the surface ocean.

Thirty-seven ostracode species are identified from 15 samples from lithological Units II and III at the type locality of the middle Pleistocene (Marine Isotope Stage 11: ca. 0.41 Ma) Takatsukayama Member of the Meimi Formation, Hyogo Prefecture, western Japan. Three ostracode biofacies are distinguished on the basis of Q-mode cluster analysis. The depositional environments of each biofacies can be inferred as bay sandy coast (BC), enclosed inner bay (IB) and middle bay influenced by freshwater inflows from rivers on the Harima Plain (CB). A rapid increase in water depth from bay coast to middle bay occurred at the deposition of the middle part of Unit II of the Takatsukayama Member. Sinocytheridea impressa (Brady), which probably disappeared or rapidly decreased from paleo-Osaka Bay at about 0.3–0.35 Ma, is abundant at the study site. One of the reasons for the disappearance or rapid decrease of this species is likely that paleo-Osaka Bay changed from a low-salinity, enclosed nutrient-rich and highly turbid bay to a moderate salinity, ventilated bay with good circulation, together with the vicariance event suggested by previous studies. This change was probably linked with both widespread inundation in the neighboring paleo-Harima-nada Bay and the development of large-scale tidal currents from the Akashi Strait connecting both bays. Thereafter, Neomonoceratina delicata Ishizaki and Kato replaced S. impressa and became the dominant taxon in paleo-Osaka Bay. Sinocytheridea impressa which lived in paleo-Osaka and Harima-nada Bays has larger valves than any specimens of this species from Recent seas. The cause of this large size in the past might have been an abundant food supply or dissolved chemicals from freshwater inflows into paleo-Osaka and Harima-nada Bays. Alternatively, whether large-valve populations occurred as a result of genetic changes in relation to the geographical isolation or not, natural selection operated in favor of increased valve size in paleo-Osaka and Harima Bays for reasons that are as yet uncertain.

Lamniform sharks (Chondrichthyes: Elasmobranchii) are common in the fossil record but are represented mainly by isolated teeth. A phylogenetic analysis of 15 extant lamniform species based on 42 morphological characters using Scyliorhinus (Carcharhiniformes) as an outgroup produces a consensus tree with the following generic relationships: [Mitsukurina [Carcharias Odontaspis Pseudocarcharias Megachasma [Alopias [Cetorhinus [[Isurus Carcharodon] Lamna]]]]]. When an extinct form, Cretoxyrhina mantelli, is added to the analysis, the fossil taxon occurs within the Alopias clade. Comparisons among the cladogram based on 29 non-dental characters alone, that based on 19 dental characters, and that based on combined (48) characters, suggest that dental characters provide at least some phylogenetic signal. Mapping of quantitative dental data on the cladogram based on non-dental characters suggests 1) a decrease in the number of tooth rows through lamniform phylogeny, 2) possible relationships between the crown heights and food types or feeding habits, and 3) that narrower crowns are plesiomorphic in lamniforms.

A new fossil pinnotherid crab, Globihexapus kosekii sp. nov. is described from the early to middle Miocene Niijukutoge Formation in Shichikashuku-machi, Miyagi Prefecture, northeast Japan. Based on the presence of five pairs of pereiopods as revealed in an examination of the present material and reexamination of the types of Globihexapus Schweitzer and Feldmann, 2001, this genus is transferred from the family Hexapodidae Miers, 1886 to the subfamily Asthenognathinae Stimpson, 1858 of the family Pinnotheridae de Haan, 1833.

A new genus and species of the family Amblypteridae, Tchekardichthys sharovi, from the Lower Permian of Eastern Europe (Perm Region of Russia) is described. It can be distinguished from all the known members of the family in the position of the fins and number of fin rays, characters of scalation and cranial roofing bones ornamentation, etc. The newly described taxon apparently lived in estuarine or brackish-water habitats.

Khantausia tshuiliensis gen. et sp. nov. is described from the Lower Permian deposits of the Tshu-Ili Mountain region in Southeastern Kazakhstan. This taxon resembles the families Amblypteridae and Rhabdolepididae in general appearance, position and shape of fins, and scale structure. It differs from both these families in the structure of the opercular series of bones. The well-developed dorsal ridge scutes originating well behind the occiput is also a distinctive character of Khantausia. Several advanced characters, like the presence of patches of small irregular scales at the fin bases, the absence of laniary teeth, the bluntly rounded snout without distinct rostrum, and other skull characters in combination, support close relationships between Khantausia and Amblypteridae. However, this new genus differs in the absence of medial extrascapular, dermohyal, and perhaps spiracular, and in the presence of a single bone in the demosphenotic region. The new genus is believed to be a probable sistertaxon for amblypterids. It is supposed that a revision of the palaeoniscoid classification based mostly on the structure of the opercular series of bones is needed.