Fukui Prefectural Dinosaur Museum

Katsuyama, Japan

Fukui Prefectural Dinosaur Museum

Katsuyama, Japan
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Iba Y.,Hokkaido University of Education | Sano S.-I.,Fukui Prefectural Dinosaur Museum | Mutterlose J.,Ruhr University Bochum | Kondo Y.,Kochi University
Geology | Year: 2012

Belemnites (order Belemnitida), a very successful group of Mesozoic cephalopods, provide an important clue for understanding Mesozoic marine ecosystems and the origin of modern cephalopods. Following current hypotheses, belemnites originated in the earliest Jurassic (Hettangian, 201.6-197 Ma) with very small forms. According to this view their paleobiogeographic distribution was restricted to northern Europe until the Pliensbachian (190-183 Ma). The fossil record is, however, biased by the fact that all the previous studies on belemnites focused on Europe. Here we report two belemnite taxa from the Hettangian of Japan: a new species of the Sinobelemnitidae and a large taxon of the suborder Belemnitina. The Sinobelemnitidae, which may be included in the future in a new suborder, have also been recorded from the Triassic of China, specimens so far poorly understood. The presence of a very large rostrum attributed to the Belemnitina suggests in addition that a diverse belemnite fauna evolved earlier than previously thought. Our new fi ndings therefore (1) extend the origin of the belemnites back by ~33 m.y. into the Triassic, (2) suggest that this group did not necessarily originate in northern Europe, and (3) imply that belemnites survived the Triassic-Jurassic extinction, one of the fi ve big mass extinctions in the Phanerozoic. Since belemnites provided a considerable amount of food as prey, the origination of belemnites is probably an important event also for the evolution of their predators, such as marine reptiles and sharks. © 2012 Geological Society of America.


Kubo T.,Fukui Prefectural Dinosaur Museum | Kubo M.O.,University of Tokyo
Palaios | Year: 2013

Fossilized trackways have rarely been analyzed quantitatively to examine major trends and patterns in evolution despite their potential utility, especially in understanding locomotory evolution. In the present study, trackways of Triassic archosauriforms were analyzed. The analyses showed foot and stride lengths of archosauriforms increased from the Early to Middle Triassic, especially those of dinosauromorphs, which tripled. Dinosauromorphs were much smaller in foot length and stride length compared to other archosauriforms during the Early Triassic. They reached similar stride length compared with other archosauriforms during the Middle Triassic and similar foot length in the Late Triassic. Stride/foot ratio is significantly higher in dinosauromorphs compared to other archosauriforms throughout the Triassic. This relatively long stride length of dinosauromorphs is attributed to either faster speed or higher relative hip height that was probably caused by their digitigrade foot posture. Analyses of trackway data sets, especially in combination with precise trackmaker assignment and age determination, would bring us more thorough knowledge about locomotory evolution of tetrapods that complements body fossil evidence. © 2013 SEPM (Society for Sedimentary Geology).


Kubo T.,Fukui Prefectural Dinosaur Museum | Kubo M.O.,University of Tokyo
Paleobiology | Year: 2012

Bipedalism evolved more than twice among archosaurs, and it is a characteristic of basal dinosaurs and a prerequisite for avian flight. Nevertheless, the reasons for the evolution of bipedalism among archosaurs have barely been investigated. Comparative analysis using phylogenetically independent contrasts showed a significant correlation between bipedality (relative length of forelimb) and cursoriality (relative length of metatarsal III) among Triassic archosaurs. This result indicates that, among Triassic archosaurs, bipeds could run faster than quadrupeds. Bipedalism is probably an adaptation for cursoriality among archosaurs, which may explain why bipedalism evolved convergently in the crocodilian and bird lineages. This result also indicates that the means of acquiring cursoriality may differ between archosaurs and mammals. © 2012 The Paleontological Society. All rights reserved.


Kubo T.,Fukui Prefectural Dinosaur Museum | Mitchell M.T.,Royal Tyrrell Museum of Palaeontology | Henderson D.M.,Royal Tyrrell Museum of Palaeontology
Journal of Vertebrate Paleontology | Year: 2012

A new elasmosaurid plesiosaur, Albertonectes vanderveldei, gen. et sp. nov., is described on the basis of an almost complete postcranial skeleton from the upper Campanian, Bearpaw Formation in Alberta, Canada. The new taxon is distinguished by a unique set of characters76 cervicals, lateral longitudinal ridge on posterior-most cervicals, relatively wide clavicular arch, tapered ventral projection at the median symphysis of coracoids, pointed anterolateral projection of pubis, fused posterior-most caudal vertebrae, and a relatively slender humerus. Ninety-seven chert gastroliths were also recovered with the specimen, and their mean diameters range from <1 to 13.5 cm. Shape analysis indicates that most of the gastroliths were ingested in the vicinity of a beach environment. Evidence that the carcass was scavenged by sharks includes a tooth-marked coracoid, two shed Squalicorax sp. teeth, and small, localized disruptions to the skeleton. Preliminary phylogenetic analysis confirms the inclusion of Albertonectes in a clade comprised of middle to Late Cretaceous, long-necked elasmosaurid plesiosaurs. The number of cervical vertebrae associated with different elasmosaur genera does not show any correlation with phylogeny. Both neck and total body length of Albertonectes are the longest among known elasmosaurs, and highlight the morphological extremes attained by this group of plesiosaurs. © 2012 Copyright Taylor and Francis Group, LLC.


The earliest fossil record of the genus Pseudotsuga (Pinaceae) in Asia, Pseudotsuga tanaii Huzioka, was reexamined with additional materials of seeds, leaves, cones, and twigs from the earliest Miocene Shichiku Flora of the Joban area, northeast Japan. These specimens were restudied to better understand the relationship of these fossils with the extant and fossil species from Asia. Pseudotsuga tanaii not only shows characters common to the modern species in East Asia, but also yields similar characters seen in the American clade. Thus, it could be an ancestral taxon of the Asian clade, which appeared before the diversification of the East Asian species. In contrast to the extant Pseudotsuga species growing under warm-temperate climate conditions at middle to high elevations in the mountains, Pseudotsuga tanaii appears to have been associated with lowland vegetation growing at lake margins. Forest vegetation associated with the species is equivalent to the Mixed Northern Hardwood forest, which develops under cooler climatic conditions. The inferred habitat of Pseudotsuga tanaii and its age support the hypothesis based on molecular phylogeny and morphological analyses that the genus originated in the higher latitudes during the early Paleogene and migrated south following the climatic deterioration during the late Paleogene. © 2011 by the Palaeontological Society of Japan.


Ichishima H.,Fukui Prefectural Dinosaur Museum
Memoir of the Fukui Prefectural Dinosaur Museum | Year: 2011

The mammalian ethmoid is situated between the walls of the orbits and is bounded dorsally by the frontal, laterally by the maxilla, and ventrally by the vomer and palatine. It consists of four parts: a horizontal or cribriform plate, forming part of the internal cranial base; a median perpendicular plate, constituting part of the nasal septum; and two lateral masses or labyrinths. The perpendicular plate of the ethmoid is also referred to as the mesethmoid. The mesethmoid has widely been recognised in odontocetes, regardless of extant or extinct, but previous studies showed that the mesethmoid was absent in some groups of mammals. The close examination of bones and cartilages forming the internal cranial base of neonatal and perinatal dolphins, infant wild boars, and a newborn calf reveals that it is most likely that the cetaceans have no mesethmoid. © by the Fukui Prefectural Dinosaur Museum.


Kubo T.,Fukui Prefectural Dinosaur Museum
Memoir of the Fukui Prefectural Dinosaur Museum | Year: 2011

Discoveries of Triassic non-dinosaur dinosauromorphs since 2000 revealed that they were more widely spread chronologically and geographically than previously thought. A member of silesaurids, the sister clade of dinosaurs, Silesaurus was a quadrupedal and herbivorous animal that differs considerably from the condition previously assumed for the ancestor of dinosaurs that are bipedal and carnivorous. Currently, stance and diet of the common ancestor of dinosaurs are not clear. To redeem this situation, Ancestral State Reconstruction methods were conducted to infer how quadrupedality and herbivory were evolved among dinosauromorphs. The results of analyses indicate that quadrupedal stance evolved only among silesaurids. Herbivorous diet was readily evolved from carnivorous diet among Dinosauromorpha and the ancestral state reconstruction using likelihood methods indicated that the possibility of the common ancestor of dinosaurs being herbivore is more than 60%. © by the Fukui Prefectural Dinosaur Museum.


Kubo T.,Fukui Prefectural Dinosaur Museum
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2011

The body mass of extinct animals have never been estimated from footprints, despite its potential utility. To redeem this situation, the relationship between body mass and the areas of footprints was derived from 17 species of modern tetrapods. Body mass of seven ichnospecies of pterosaur tracks were estimated, because pterosaur body weight is an intriguing topic with reference to their flying ability. Estimated body weights of pterosaurs range from 110. g to 145. kg. The result provides evidence that large pterosaurs are about 10 times heavier than the heaviest modern bird. © 2010 Elsevier B.V.


Terada K.,Fukui Prefectural Dinosaur Museum
Memoir of the Fukui Prefectural Dinosaur Museum | Year: 2013

A single isolated cone-scale fossil of Swedenborgia was discovered from the Lower Jurassic Kuruma Group at the Kuruma area of Nagano Prefecture for the first time. The fossil is closely similar to S. sp. A, which was reported from the Lower Jurassic Iwamuro Formation of Gunma Prefecture by Kimura and Tsujii(1984). Furthermore, the fossil resembles the specimens which were reported as S. cryptomerioides Nathorst from the Upper Triassic Nariwa Group(Okayama Prefecture)and the Upper Triassic Mine Group(Yamaguchi Prefecture). The Kuruma specimen exclusively occurs with a lot of leafy shoots of Podozamites ex gr. distans(Presl)Braun. This additionally supports the idea that Swedenborgia is one of the female reproductive organs of certain narrow-leaved species of Podozamites. © by the Fukui Prefectural Dinosaur Museum.


Sano S.-I.,Fukui Prefectural Dinosaur Museum
Memoir of the Fukui Prefectural Dinosaur Museum | Year: 2013

Ammonoid fossils including Tithonian Parapallasiceras sp. are newly discovered from the Kurotodo Formation of the Tetori Group in the Ono area of the Kuzuryu district, Ono City, Fukui Prefecture in the Hida Gaien Belt, Central Japan. Based on this find, the Kurotodo Formation can now be correlated with the Early Tithonian Kamihambara Formation in the Kamihambara area of the same district, despite its previous assignment to the Middle Jurassic(Bathonian-Callovian)Kaizara Formation of the Kuzuryu Subgroup(lower part of the Tetori Group)in the Hida Belt. Similar lithological successions ranging from Oxfordian to Barremian in age, including ammonoids-bearing Oxfordian and Tithonian formations referred to the early and middle transgressions(stage Ib and IIa)of the Tetori Group, are recognized throughout the Mana-Ono and Nagano-Kamihambara areas in the Hida Gaien Belt and are, at least partly, synchronous with the main part of the Itoshiro Subgroup(middle part of the Tetori Group)of the Itoshiro area of the Kuzuryu district in the Hida Belt. The Kaizara Formation and its equivalents, representing the early transgression(stage Ia:Bathonian to Callovian)of the Tetori Group, is probably confined within the Hida Belt, contrary to the hitherto accepted view that it is distributed widely not only in the Hida Belt but also in the Hida Gaien Belt. © by the Fukui Prefectural Dinosaur Museum.

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