Temporal species-diversity changes in Japanese Cretaceous inoceramid bivalves were analyzed from an extensive literature survey and statistical analysis, with the following results: (1) Species diversity increased gradually from the Upper Albian to Lower Campanian, and then dropped suddenly across the Lower/Upper Campanian (LCa/UCa) boundary; (2) There is no statistical correlation between ammonoid and inoceramid diversity changes in Japan, which must reflect the different ecologies of both groups; (3) Relatively high extinction ratios occurred at boundaries near Oceanic Anoxic Events (OAEs). The extinction events at the Albian/Cenomanian, Cenomanian/Turonian, and Turonian/Coniacian boundaries were potentially caused by OAE1d, 2 and the onset of OAE3, respectively. The drastic diversity decrease at the LCa/UCa boundary probably resulted from an abrupt and large-scale relative sea-level fall in the Yezo forearc basin; and (4) The pattern of diversity changes is similar to that of long-term (2nd-order) eustatic sea-level changes. The following hypotheses are presented as the cause of these phenomena: changes in shelf area, the primary inoceramid habitat, controlled their diversity, or changes in the Cretaceous outcrop area (rock volume) associated with sea-level changes controlled their diversity. It is possible that a combination of both factors controlled diversity patterns.

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Two new species of trigonoceratid nautilids from the middle Chesterian (Early Carboniferous) Pitkin Formation of Arkansas, Midcontinent North America are described. Epistroboceras pitkinense sp. nov. is most similar to E. caneyense Niko and Mapes, 2004, but is distinguished mainly by its dorsally shifted umbilical angle. Stroboceras gordoni sp. nov. is characterized by the narrow lg 2 (second lateral groove) in the lateral grooves, the two bilaterally symmetrical lateral ridges, and the weak nodes at intersections of ridges and the growth lines. Species previously described or assigned to Stroboceras are re-examined. Similarities in the shell morphology between the trigonoceratid nautilid Stroboceras and the isochronous Early Carboniferous ammonoid Eumorphoceras probably provide an example of synchronized convergent evolution.

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We describe five new dento-gnathic specimens of Tetraconodon, a genus of Miocene tetraco nodontine suid (Mammalia, Artiodactyla), discovered in Myanmar (= Burma). In Myanmar, we recognized three distinct species of Tetraconodon (T. minor, T. intermedius and T. malensis sp. nov.) and one specifically undetermined specimen, which is here named Tetraconodon sp. cf. T. intermedius. The new species, T. malensis, has characteristics of Tetraconodon, such as extremely enlarged P₄ and simple and relatively small M₃. It is distinct from the other Tetraconodon species in being much smaller, suggesting that it is the most primitive known Tetraconodon species. The dental size and characteristics of T. malensis suggest that Tetraconodon was derived during the late middle Miocene from the early middle Miocene Conohyus sindiensis, which was discovered in the Siwalik Group of Indo-Pakistan and Nepal and has also been found in the middle Miocene deposits of Thailand, or a close relative. The discovery of the most primitive form in Myanmar suggests that Tetraconodon may have originated in Myanmar.

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Modern planktic foraminifera in 51 surface sediments from the Japan Sea, a marginal sea of the western North Pacific, were studied to reveal the relationships between geographical distribution and surface water masses in the Japan Sea. Twenty-four species belonging to 10 genera were identified, of which nine species, namely Neogloboquadrina incompta, Neogloboquadrina pachyderma, Globigerina quinqueloba, Globigerina bulloides, Globigerinoides ruber, Neogloboquadrina dutertrei, Pulleniatina obliquitoculata, Globigerinoides tenellus, and Globigerinita glutinata are predominant. We recognized four geographical distribution patterns of these dominant species that are related to hydrographic conditions in the Japan Sea. The transitional water formed by the mixture between the warm Tsushima Current and cold waters in the Japan Sea is optimal for N. incompta, while the distribution of N. pachyderma is matched with cold water in the northern Japan Sea. Globigerina quinqueloba and G. bulloides appear to be associated with less saline, nutrient-rich river water from the Changiiang (Yangtze River), and G. ruber, N. dutertrei, P. obliquitoculata, G. tenellus, and G. glutinata can be regarded as indicators of Tsushima Current water.

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