An almost intact specimen of an uppermost Cretaceous heteromorph ammonoid, Pravitoceras sigmoidale Yabe, was recently discovered from the Hakobuchi Formation of the Yezo Supergroup in the Hidaka area, Hokkaido. The specimen is preserved in a lenticular calcareous nodule. It retains two whorls of planispiral phragmocone and a succeeding retroversal hook, which is associated with a lower jaw apparatus near the aperture. P. sigmoidale occurs within the Inoceramus shikotanensis Zone at the Hidaka section. Patagiosites alaskensis, Gaudryceras sp., Inoceramus shikotanensis, and Gigantocapulus problematicus cooccur with P. sigmoidale. The megafossil assemblage resembles those of the Upper Campanian-Lower Maastrichtian in the Sakhalin area. P. sigmoidale has a very short range assignable to the Upper Campanian. However, it has been assumed to be an endemic species of the Izumi Group in southwest Japan, and has never before been found from northeast Japan. Scarcity of common zone-indexing taxa is a bottleneck for biostratigraphic research of the uppermost Cretaceous System in Japan. The first discovery of P. sigmoidale from the Hidaka area is a significant step for much more precise biostratigraphic correlation between the Yezo Supergroup and the Izumi Group.

A polyplacophoran fauna in the Akasaka Limestone is significantly different from previously described Permian faunas. Gryphochiton Gray, 1847, is the only genus present commonly found in other faunas. Four genera and species including Gryphochiton asamiae sp. nov., Aaptochiton pustulosus gen. et sp. nov., Gifuochiton pentagonus gen. et sp. nov., Crassitudochiton plakos gen. et sp. nov., and Crassitudochitonidae fam. nov. are described. Small pustules on many plates indicate ends of aesthete canals.

A new genus and species of coelacanth, Parnaibaia maranhaoensis gen. et sp. nov. is described on the basis of four specimens from the Pastos Bons Formation in Maranhao, Brazil. This new genus and species differs from other genera of the family Mawsoniidae by having a stout median ridge on the scales, six free extrascapulars, seven elements in the supraorbital-tectal series and absence of large teeth. P. maranhaoensis bridges the gap between the Triassic Chinlea and Cretaceous Mawsonia and Axelrodichthys.

Color markings of the potamidid gastropods Vicarya yokoyamai Takeyama, 1933 and Vicarya verneuili (d’Archiac, 1851), tropical and subtropical, mangrove-swamp and/or nearby intertidal dwellers during the Miocene in Southeast Asia, Pakistan, Korea and Japan, have been reconstructed. This reconstruction was based on preserved original color markings and UV-light photography associated with computer graphic processing of specimens of V. yokoyamai and V. verneuili from Japan, the Philippines and Indonesia. The results strongly suggest that the two Vicarya species have basically the same spiral color bands on the thick subsutural spiny cord, fine spiral cords of the whorl surface and shell base. Some individual variation was detected in V. yokoyamai, such that the fine spiral cords are suggested to have color pigment the same as or lighter than the whorl surface, and the thick subsutural spiny cords are pigmented either totally or only at the tips of the robust spines. The color markings reconstructed in this paper provide an additional shell character for the controversial relationship among the Vicarya species and subspecies proposed previously.

Six ostracode species were discriminated from the latest Eocene-earliest Oligocene marine sediments in Kurashiki City, Okayama Prefecture along the Seto Inland Sea in southwestern Japan. The ostracode assemblage is characterized by Munseyella setouchiensis and Acanthocythereis kurashikiensis sp. nov. They inhabited the lower sublittoral zone, affected by ocean waters. The new record from the Kurashiki area indicates that the eastern area of the Seto Inland Sea was under a cooler marine climate than the Kyushu region from the late Middle Eocene to earliest Oligocene. All the species including a new species, Acanthocythereis kurashikiensis sp. nov., are described systematically.

We describe fossil specimens of two taxa of anthracotheriid artiodactyls (Mammalia) discovered in the upper Eocene Ergilin Dzo Formation of southeastern Mongolia and briefly review the late Eocene anthracotheriids of northern East Asia. The specimens described here are: (1) an upper molar, an astragalus, and a calcaneum of a small bunodont anthracotheriid; and (2) upper and lower postcanine dentitions, an astragalus, and a distal tibia of a Bothriodon/Aepinacodon-like selenodont anthracotheriid. This paper provides the first description and figures of the Anthracotheriidae from the formation, which were hitherto poorly understood. The anthracotheriid fauna of the formation currently consists of two species, an indeterminate bunodont anthracotheriid and cf. Bothriodon sp. This is the first discovery of a bunodont anthracotheriid in the late Eocene of the northern part of East Asia. The anthracotheriids are mainly represented by selenodont and bunoselenodont species and are rare faunal elements in the late Eocene of northern East Asia; in contrast, they are mainly represented by bunodont and bunoselenodont species and are predominant faunal elements in the late Eocene of southern East Asia. This implies a paleobiogeographical separation between the northern and the southern parts of East Asia during the late Eocene.

None of the “Big Five” mass extinctions occurred during the Silurian Period. However, a very good regional record from the northern part of the Greater Caucasus makes it possible to evaluate the strength of the Silurian events. During the mid-Paleozoic, the study region belonged to the Hun Superterrane, having been located in between the Prototethys-Rheic and Palaeotethys oceans. An analysis of the stratigraphic ranges of 99 graptolite and 35 conodont species, coupled with improvements in the regional stratigraphic framework, reveals a Llandovery peak in graptolite diversity and a subsequent decline towards the end of the Silurian. In contrast, conodonts radiated during the late Ludlow and remained quite diverse in the Pøidoli. The regional and global dynamics of both groups correspond quite well. Among a number of regional biotic crises, the most outstanding occurred at the Llandovery-Wenlock transition, the global analogue for which is the Ireviken Event. This might have been a true mass extinction. Although the only potential mass extinction (i.e., the Ireviken Event) evidently corresponded to regional and global abrupt sea-level fall, eustasy appears an unlikely cause of the observed diversity changes. An increase in carbonate sedimentation in the late Silurian explains the long-term trends in graptolite and conodont diversity changes. Bottom water changes and glaciations were among the probable triggers of the Ireviken Event. Extraterrestrial impact also may be hypothesized to explain this short-term event, whereas no large superplume activity is known from the Silurian.

A Middle Triassic radiolarian fauna is present in the siliceous rock section at the Nan area along the Nan-Uttaradit suture zone, northern Thailand. The radiolarian fauna is composed of Triassocampe deweveri, T. nishimurai, Annulotriassocampe campanilis, Cenosphaera igoi, and other species and corresponds to the Anisian (Middle Triassic) Triassocampe deweveri fauna reported from Japan, Hungary, Italy, Austria, Far East of Russia, and northern and eastern Thailand. More than fifteen radiolarian species belonging to eight genera are investigated. The radiolarian-bearing rocks were probably deposited in a pelagic environment within the Nan-Uttaradit back-arc basin between the Simao and Indochina blocks during Middle Triassic time. This suggests that the Nan-Uttaradit back-arc basin, the Palaeo-Tethys ocean and Panthalassa ocean were probably connected by seaways at this time and might have shared the same oceanic circulation system. Furthermore, the complete closure of the Nan-Uttaradit back-arc basin between the Simao and the Indochina blocks is thought to have occurred at least after the Middle Triassic.

Limestone fragments with Late Paleozoic foraminifers were distinguished at Okusukain and Aisaka, north of Himeji, Nishi-Harima district, Hyogo, Japan. They are contained within matrix-supported conglomerate of caldera-originated lacustrine deposits in the Upper Cretaceous Hiromine Formation, which is mostly composed of volcaniclastic rocks. Age distribution of the limestone fragments is variable in comparison with their very rare occurrence. Late Visean, Serpukhovian or early Bashkirian, Moscovian, Wordian and Lopingian ages were attached to the fragments based on their age diagnostic foraminifers, in addition to questionable post-Triassic limestone cobble. All of these limestone fragments are thought to have been derived from the Akiyoshi and Maizuru terranes, and have special paleogeographic and tectonic implications in relation to the nappe tectonics of the Inner Zone of Southwest Japan.