A5001609412- Paleontology and Stratigraphy of Fossils
- Mollusks and Parasites Studies
- Cephalopods and Marine Biology
- Geochemistry and Elemental Analysis
- Marine Biology and Ecology Research
- Geology and Paleoclimatology Research
- Paleontology and Evolutionary Biology
- Plant Taxonomy and Phylogenetics
- Botany, Ecology, and Taxonomy Studies
- Fossil Insects in Amber
- Morphological variations and asymmetry
- Aquatic Invertebrate Ecology and Behavior
- Evolution and Paleontology Studies
- Fish Ecology and Management Studies
- Plant and animal studies
Fukui Prefectural Dinosaur Museum
2021-2023
University of Tsukuba
2016-2019
Abstract Other than hard bones and shells, it is rare for soft tissues to fossilize, but occasionally they are well-preserved in amber. Here, we focus on both modern fossilized species of the land snail superfamily Cyclophoroidea. Phylogenetic relationships within Cyclophoroidea were previously studied using extant species, timing divergence group remains unclear. In addition, difficult observe morphological traits such as chitinous operculum periostracum fossil snails due their poor...
The extraordinarily large and aberrantly shaped shells of the Permian bivalve family Alatoconchidae (Ambonychioidea), thought to have a photosymbiotic mode life like modern fragine Corculum, are difficult extract from their host limestone bodies; therefore, morphologies been reconstructed mostly based on broken shell pieces. alatoconchid Shikamaia akasakaensis Ozaki, type species genus middle Akasaka Limestone central Japan, was described only three fragmentary specimens; its characters were...
Pleurotomaria yokoyamai Hayasaka is a remarkably large gastropod commonly found in the middle Permian allochthonous Akasaka Limestone of central Japan. Its supraspecific systematics have however been unsettled. Examination museum collection and newly obtained material reveal previously unreported shell characteristics such as presence long labral slit outer lip slit-like umbilicus surrounded by an accretionally growing callus pad. On basis these known characters, new genus Nipponomaria...
The class Bivalvia (phylum Mollusca) is one of the most successful at survival groups animals with diverse color patterns on their shells, and they are occasionally preserved in fossil record as residual patterns. However, freshwater bivalves could be traced only to Miocene, greatly limiting pattern evolution knowledge. We present Cretaceous belonging three extinct families order Trigoniida (hereinafter Kitadani Freshwater Bivalves) from Japan, which oldest second molluscan Bivalves consists...
長崎半島東海岸に露出する上部白亜系"北浦層"を長崎北浦層と改定した.本層は下部の赤崎ノ鼻砂岩泥岩部層と上部の座頭浜礫質砂岩泥岩部層に二分でき,両部層は断層で接する.赤崎ノ鼻砂岩泥岩部層から産した2種のアンモナイト類(Polyptychoceras obataiとcf. Phylloceras sp.)と1種のイノセラムス類(Platyceramus japonicus),座頭浜礫質砂岩泥岩部層から産したハドロサウルス上科の鳥脚類恐竜の大腿骨化石を記載した.赤崎ノ鼻砂岩泥岩部層の軟体動物化石と砕屑性ジルコンのU-Pb年代から,長崎北浦層の時代は後期サントニアン期以降であり,おそらくカンパニアン期におよぶ.座頭浜礫質砂岩泥岩部層は岩相から長崎半島西海岸の三ツ瀬層の下部(中期カンパニアン期)に対比できる.長崎北浦層の層序は西九州の上部白亜系姫浦層群の下半部に関連すると考えられる.
Abstract The phylum Bivalvia is one of the most successful at survival groups animals with diverse color patterns on their shells, and they are occasionally preserved in fossil record as residual patterns. However, freshwater bivalves could be traced only to Miocene, greatly limiting pattern evolution knowledge. We present Cretaceous (hereinafter Kitadani Freshwater Bivalves) from Japan, which oldest second molluscan Bivalves consists two types patterns: stripes along growth lines radial...
Abstract Paleozoic scaphopods are among the most poorly known mollusks because of their featureless tubular shell morphology and fragmentary preservation. An apical orifice at posterior end a conch is diagnostic character Scaphopoda that distinguishes them from other groups animals produce similar calcareous tubes, but this structure rarely preserved. A rich molluscan fauna Permian Akasaka Limestone in central Japan includes scaphopod shells, past studies have reported four species, all...