SMALL MAMMAL FOSSILS AND CORRELATION OF CONTINENTAL DEPOSITS, SAFFORD AND DUNCAN BASINS, ARIZONA (GILA CONGLOMERATE, MAGNETOSTRATIGRAPHY, BIOCHRONOLOGY, BLANCAN AGE, TAXONOMY).

Fossil bearing continental deposits, the Gila Conglomerate, of the Safford and Duncan Basins, Arizona were correlated with the magnetic polarity time scale by means of magnetostratigraphy and biochronology of mammalian fossils. Within the Safford Basin, the Bear Springs section with a middle Blancan fauna is correlated with the lower or upper Gauss chron; the 111 Ranch section with a middle to late Blancan fauna is correlated with the upper Gauss to early Matuyama chrons; and the San Simon Power Line section with probably a latest Blancan fauna is correlated with the early Matuyama chron. In the Duncan Basin, the Duncan section with a middle Blancan fauna is correlated with the middle Gauss chron; the Pearson Mesa section with a middle Blancan fauna is correlated with the Upper Gauss chron; and the Country Club section with a middle Blancan fauna is correlated with the latest Gilbert to early Gauss chrons or from the middle Gauss to the earliest Matuyama chrons. A late Blancan fauna is not recognized in the Duncan Basin at least within the study area, whereas the Gila Conglomerate in the Safford Basin includes deposits and fauna of the latest Blancan (latest Pliocene) age. A minimum of 37 taxa of small mammals are recognized among the approximately 1,600 specimens from the Gila Conglomerate of the Safford and Duncan Basins. Three new rodent species are described; they are Pappogeomys (Cratogeomys) sansimonensis, new species; Reithrodontomys galushai, new species; and Repomys arizonensis, new species. One new combination of genus and species, Hypolague virginiae, is described. In the Safford Basin, a minimum of 26 small mammal taxa are now recognized in the 111 Ranch fauna, of which three genera (Dipodomys, Peromyscus, and Repomys) are new records to the fauna; a minimum of 6 taxa of small mammals are recognized and described for the first time in the San Simon Power Line fauna. In the Duncan Basin, a minimum of 15 small mammal taxa are recognized and described for the first time

Titanosauriform teeth from the Cretaceous of Japan

Sauropod teeth from six localities in Japan were reexamined. Basal titanosauriforms were present in Japan during the Early Cretaceous before Aptian, and there is the possibility that the Brachiosauridae may have been included. Basal titanosauriforms with peg-like teeth were present during the "mid" Cretaceous, while the Titanosauria with peg-like teeth was present during the middle of Late Cretaceous. Recent excavations of Cretaceous sauropods in Asia showed that multiple lineages of sauropods lived throughout the Cretaceous in Asia. Japanese fossil records of sauropods are conformable with this hypothesis

The Eomyidae in Asia: Biogeography, diversity and dispersals

In Asia, the first find of an eomyid rodent was reported almost one century after the first studies of the family Eomyidae in North America and Europe. Since then, eomyid rodents have been increasingly found in Asia particularly over the past two decades. Here, we review the Asian record of this family at the genus level. Currently, 22 species within 14 genera were reported from Asia, including seven endemic genera and rare materials of apeomyine eomyids. Eomyids emphasize the palaeogeographic importance of Asia in considering intercontinental dispersal events of small mammals. With newly compiled data for Asian eomyids, we also compare genus-level diversity trends through time among North America, Europe, and Asia. Despite data standardizations limited with respect to potential biases in the fossil record, we found that the Asian eomyid diversity closely follows ecological shifts induced by climate changes. In general, Asian eomyid genera disappeared earlier than their European counterparts. We suggest that this pattern is not dictated by differences in the quality of the fossil record and is related to the expansion of drier habitats over large areas of Asia

A new endemic genus of eomyid rodents from the early Miocene of Japan

Fossil rodents are generally scarce in the Miocene of Japan. However, as much as three taxa of eomyid rodents had been reported from the early Miocene Nakamura Formation (ca. 18.5 Ma) in Gifu Prefecture, central Japan. In this study, we revisit one of them-the small-sized taxon-and assign this material to a new genus, Japaneomys, which is so far known only from the type locality. The new genus is closely related to but distinguished from Asianeomys, which is more widely distributed in Central and East Asia, by having: (i) more bunodont cheek teeth with lower lophids, yet complete transverse lophids; (ii) two-rooted p4; (iii) anterior lobe narrower than posterior lobe on m1, correspondingly synclinid I shorter and shallower than synclinid IV; (iv) hypolophid anteriorly concave on m1. Japaneomys shows a derived but peculiar four-layered enamel microstructure with longitudinally oriented Hunter-Schreger bands, compared to three-layered microstructure in typical eomyid rodents. A phylogenetic analysis indicates that Japaneomys is more basal than Asianeomys and likely diverged in the late Oligocene when Japan was still part of the eastern margin of continental Asia, suggesting that certain small mammal populations could have undergone allopatric speciation isolated from inner-continental regions of Asia

A new endemic genus of eomyid rodents from the early Miocene of Japan

Fossil rodents are generally scarce in the Miocene of Japan. However, as much as three taxa of eomyid rodents had been reported from the early Miocene Nakamura Formation (ca. 18.5 Ma) in Gifu Prefecture, central Japan. In this study, we revisit one of them-the small-sized taxon-and assign this material to a new genus, Japaneomys, which is so far known only from the type locality. The new genus is closely related to but distinguished from Asianeomys, which is more widely distributed in Central and East Asia, by having: (i) more bunodont cheek teeth with lower lophids, yet complete transverse lophids; (ii) two-rooted p4; (iii) anterior lobe narrower than posterior lobe on m1, correspondingly synclinid I shorter and shallower than synclinid IV; (iv) hypolophid anteriorly concave on m1. Japaneomys shows a derived but peculiar four-layered enamel microstructure with longitudinally oriented Hunter-Schreger bands, compared to three-layered microstructure in typical eomyid rodents. A phylogenetic analysis indicates that Japaneomys is more basal than Asianeomys and likely diverged in the late Oligocene when Japan was still part of the eastern margin of continental Asia, suggesting that certain small mammal populations could have undergone allopatric speciation isolated from inner-continental regions of Asia