Kuwajima Formation
Introduction The '''Kuwajima Formation''' is an Early Cretaceous geologic formation in Japan. Its precise age is uncertain due to a lack of identifying fossils, and it was previously considered likely Valanginian to Hauterivian in age. However, it is now considered to probably be Barremian in age. Dinosaurs and other vertebrates has been recovered from the Kaseki-kabe "Fossil-bluff" locality in the uppermost part of the formation.The multituberculate mammals ''Hakusanobaatar matsuoi'' and ''Tedoribaatar reini'' are known from the Kuwajima Formation. A member of Tritylodontidae, ''Montirictus kuwajimaensis'', has also been recovered from the unit.
Vertebrate Paleobiota === Fish ==='''Fish reported from the Kuwajima Formation'''GenusSpeciesLocationStratigraphic positionMaterialNotesImages''Sinamia''''S. kukurihime''Mostly complete skeletonAn amiiform fish related to bowfins''Tetoriichthys''''T. kuwajimaensis''The oldest record of Osteoglossiform=== Amphibians ==='''Amphibians reported from the Kuwajima Formation'''GenusSpeciesLocationStratigraphic positionMaterialNotesImages''Shirerpeton''''S. isajii''Kaseki-kabe Facies IIIPartial disarticulated skullAlbanerpetontidAnuraIndeterminateIsolated longbone, as well as a partial skeleton "composed of a few skull elements and several postcranial bones, including the femur, ilium, and vertebrae"Partial skeleton belongs to a basal frog that lies outside of Neobatrachia.=== Choristoderes ==='''Choristoderes reported from the Kuwajima Formation'''GenusSpeciesLocationStratigraphic positionMaterialNotesImages''Monjurosuchus''IndeterminateKaseki-kabe Facies III''Monjurosuchus''NeochoristoderaIndeterminateFacies IThe first report of a neochoristodere from JapanChoristoderaIndeterminateKaseki-kabe Facies III=== Squamates ==='''Squamates reported from the Kuwajima Formation'''GenusSpeciesLocationStratigraphic positionMaterialNotesImages''Asagaolacerta''''A. tricuspidens''Kaseki-kabe Facies III"An association of skull, jaws and postcranial bones of a small lizard with facetted tricuspid teeth, possibly a right maxilla"''Kaganaias''''Hakuseps''''H. imberis'' Kaseki-kabe Facies IIIAn almost complete left dentary''Kaganaias'' ''K. hakusanensis''Kaseki-kabe Facies III"Part and counterpart of articulated partial skeleton comprising parts of the dors. vert. series and parts of the tail, pelvis, and hind limbs"''Kuroyuriella''''K. mikikoi'' Kaseki-kabe Facies III"A disarticulated skull on four originally conjoined blocks, an association on two small blocks"''Kuwajimalla''''K. kagaensis'' Kaseki-kabe Facies III''Sakurasaurus''IndeterminateKaseki-kabe Facies III"Small block with disarticulated association of skull bones, vertebrae, ribs, pelvis and hindlimb bones"ParamacellodidaeIndeterminateKaseki-kabe Facies IIISquamata IndeterminateKaseki-kabe Facies IIIFive distinct taxa=== Dinosaurs ==='''Dinosaurs reported from the Kuwajima Formation'''GenusSpeciesLocationStratigraphic positionMaterialNotesImages''Albalophosaurus''''A. yamaguchiorum'' Kaseki-kabeFacies IIIPartial skull and lower jawsDromaeosauridae IndeterminateKaseki-kabeFacies IIIEnantiornithes IndeterminateKaseki-kabeFacies IIIOrnithischiaIndeterminateRight dentary, left maxilla, isolated teethDistinct from ''Albalophosaurus''Sauropoda ("Oharasisaurus")IndeterminateKaseki-kabeFacies IIIToothStyracosternaIndeterminateMaxillary and dental teeth=== Mammaliamorphs ==='''Mammaliamorphs reported from the Kuwajima Formation'''GenusSpeciesLocationStratigraphic positionMaterialNotesImages''Hakusanobaatar''''H. matsuoi'' Kaseki-kabeFacies IIIDentary fragments and teethEobaatarid''Hakusanodon''''H. archaeus''Kaseki-kabeFacies IIIEutriconodont''Montirictus''''M. kuwajimaensis'' Kaseki-kabeFacies IIITritylodontid''Tedoribaatar''''T. reini'' Kaseki-kabeFacies III"Fragment of right lower jaw with p4"EobaataridMultituberculata IndeterminateKaseki-kabeFacies III
Invertebrate Paleobiota '''Invertebrates reported from the Kuwajima Formation'''GenusSpeciesLocationStratigraphic positionMaterialNotesImages''Nipponoridium''''B. matsuoi''Kaseki-KabeMimarachnid hemipteran''Nipponohagla''''N. kaga''Prophalangopsid''Kagapsychops''''K. araneus''Psychopsid
See also * List of dinosaur-bearing rock formations
References