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Nishioka Y.,Kyoto University | Takai M.,Kyoto University | Nishimura T.,Kyoto University | Htike T.,Shwebo University | And 6 more authors.
Journal of Systematic Palaeontology | Year: 2015

The Upper Pliocene Irrawaddy sediments in the Gwebin area of central Myanmar recently yielded a rodent assemblage that contains nine species belonging to four families: four species of Muridae, three of Hystricidae, one of Spalacidae, and one of Sciuridae. The murids consist of Hapalomys cf. longicaudatus, Maxomys pliosurifer sp. nov., Rattus jaegeri and cf. Rattus sp. indet., which include both extinct and extant forms. Maxomys pliosurifer is relatively similar to Maxomys surifer that lives in South-East Asia in terms of tooth morphology but retains plesiomorphic features shared with the ancestral rat, Karnimata, and possible sister genera of Maxomys, such as Ratchaburimys and Millardia. The three hystricids belong to the genus Hystrix and consist of two extinct brachydont species (Hystrix paukensis and Hystrix sp. indet.) and one hypsodont species similar to living form (Hystrix cf. brachyura). This finding indicates that primitive brachydont species and derived hypsodont species of Hystrix had likely coexisted in the locality, but the brachydont species are significantly more common amongst specimens collected from the Gwebin area. The spalacid species is Cannomys cf. badius and the sciurid species is Menetes sp. indet. These two rodents are similar to living species in continental South-East Asia although they show minor differences in tooth characteristics compared to the living forms. Some species and genera of the fossil rodent assemblage from the Gwebin area also occur in Upper Pliocene localities of Thailand, suggesting chronological correlation between these two faunas. Moreover, these fossil rodent assemblages are composed primarily of the species distributed endemically in continental South-East Asia. Late Pliocene rodents of continental South-East Asia were affected by river barriers that formed during the Mio-Pliocene, and they were probably not able to disperse from South-East Asia into South and East Asia. http://zoobank.org/urn:lsid:zoobank.org:pub:0171B3BE-02D4-433C-A5CE-4729C537FAF8. © 2014 The Trustees of the Natural History Museum, London 2014. All Rights Reserved.


Hone D.W.E.,Institute of Vertebrate Palaeontology and Palaeoanthropology | Watabe M.,Hayashibara Museum of Natural science
Acta Palaeontologica Polonica | Year: 2010

Feeding traces for carnivorous theropod dinosaurs are typically rare but can provide important evidence of prey choice and mode of feeding. Here we report a humerus of the hadrosaurine Saurolophus which was heavily damaged from feeding attributed to the giant tyrannosaurine Tarbosaurus. The bone shows multiple bites made in three distinctive styles termed "punctures", "drag marks" and "bite-and-drag marks". The distribution of these bites suggest that the animal was actively selecting which biting style to use based on which part of the bone was being engaged. The lack of damage to the rest of the otherwise complete and articulated hadrosaur strongly implies that this was a scavenging event, the first reported for a tyrannosaurid, and not feeding at a kill site.


Ishigaki S.,Hayashibara Museum of Natural science | Lockley M.G.,University of Colorado at Denver
Historical Biology | Year: 2010

Two theropod trackways with alternating long-short pace lengths and a didactyl theropod trackway were discovered from Ait Blal tracksite situated in central High Atlas Mountains, Morocco. They are described here together with other tridactyl and tetradactyl footprints. The track-bearing bed belongs to the Lower Jurassic (Pliensbachian) Aganane Formation. One of the theropod trackways with alternating pace lengths indicates locomotion by a limping dinosaur. In this trackway, the pathological irregularities in the morphology of right footprints suggest that the trackmaker had injured its right foot. Another trackway with alternating pace lengths suggests the accidental problem while walking of theropod trackmaker. The morphology of the didactyl theropod trackway may be attributable to a dromaeosaurid or dromaeosaurid-like trackmaker whose body fossil remains have not been reported from the Jurassic. If the trackmaker of the didactyl prints was a dromaeosaurid, the discovery supports the idea that dromaeosaurid dinosaurs had early origins and also are ancestral to birds. © 2010 Taylor & Francis.


Tsuihiji T.,University of Tokyo | Barsbold R.,Mongolian Academy of science | Watabe M.,Osaka City University | Tsogtbaatar K.,Mongolian Academy of science | And 2 more authors.
Historical Biology | Year: 2016

New material of a troodontid theropod from Khamaryn Ar in Mongolia, representing the second troodontid specimen described from the Lower Cretaceous of the Gobi Basin, is reported. This material consists mainly of caudal, manual and pedal bones, and can be assigned to Troodontidae based on the presence of derived features such as distal caudals bearing sulci on neural arches instead of neural spines, asymmetrical pes with slender metatarsal II and robust metatarsal IV, and pedal phalanx II-2 with the distal articular surface less than half the size of the proximal surface. The present specimen is considered merely as Troodontidae gen. et sp. indet. because of the lack of definitive autapomorphies. The present finding suggests that further exploration of the Lower Cretaceous in the Gobi Basin may still provide much new information on the theropod fauna in this region. © 2016, © 2015 Taylor & Francis.


Hone D.,University College Dublin | Tsuihiji T.,National Museum of Nature and Science | Watabe M.,Hayashibara Museum of Natural science | Tsogtbaatr K.,Mongolian Academy of science
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2012

Stomach contents preserved in fossil specimens provide direct evidence for the diet of extinct animals. Such exceptional fossils remain rare for predatory non-avian dinosaurs and each can add significantly to our understanding of trophic interactions between various taxa. Here we present evidence for the dromaeosaurid theropod Velociraptor scavenging on the carcass of an azhdarchid pterosaur, with a long bone of the pterosaur being found as gut contents of the dinosaur. Despite previous inferences of dromaeosaurs as hyper-predators, scavenging appears to have been an important part of their ecology. © 2012 Elsevier B.V.


Belvedere M.,University of Padua | Dyke G.,University College Dublin | Hadri M.,University Mohamad V | Ishigaki S.,Hayashibara Museum of Natural science
Gondwana Research | Year: 2011

We revise a famous set of fossil footprints that were described in the mid-1980s from the Middle Jurassic (Bathonian) of Morocco and that have often been considered to be an early record for Mesozoic birds. If correct, these tracks are the oldest records of birds from Gondwana and would have critical biogeographic and palaeobiological implications. The oldest skeletal fossils of avians are from the Late Jurassic of Germany (Laurasia). Thus, these important historical footprints are re-described and re-examined and new analyses are carried out on the additional tracks that also occur on the surface but that have never been described before. All the tracks on the surface show the same morphological characteristics, though their size is variable, and are compared here to known dinosaur and bird ichnotaxa. We used a laser scanner to generate a 3D digital model of the slab; this new approach allowed detailed descriptions of the specimens, the identification of new footprints on the surface, and the conclusion that they were likely left by non-avian dinosaurs (rather than birds). We show the potential of this new approach to the study of fossil footprints and trackways; high-resolution imaging and laser scanning add new information fundamental for a revision of the criteria for distinguishing between closely-related vertebrate groups, in this case dinosaurs and birds. © 2010 International Association for Gondwana Research.


Belvedere M.,University of Padua | Mietto P.,University of Padua | Ishigaki S.,Hayashibara Museum of Natural science
Geological Quarterly | Year: 2010

The Late Jurassic Iouaridène tracksite has been studied for decades and is well-known for the reference trackway of Breviparopus taghbaloutensis. These siliciclastic flood-plain deposits bear probably more than 1500 tracks, and at least 21 trampled levels: they yield tracks of medium to very large sauropods, possible stegosaurs and theropods. The first accurate description of the footprint association made by biped trackmakers is proposed herein. More than six hundred footprints and more than a hundred trackways has been mapped and anaiysed; this led to the definition of four tridactyl and two tetradactyl morphotypes, mainly produced by small to very large theropods, while probable small ornithopod tracks are also present. The bipedal footprint association is dominated by medium-large theropods, which are also the most abundant type. The taxonomical attribution of the morphotypes is made difficult by the poor preservation of many specimens. Furthermore, for the most abundant theropod tracks, those with "megalosaurian" affinity, there is also a complex ichnotaxonomical situaiion, that makes the attributions yet more chalienging; however, it was possible to recognize the great affinity of the tridactyl specimens with the Megalosauripus tracks from the Iberian Peninsula and North America. Three-dimensional models were generated from the moulds of the best-preserved specimens to render a more detailed description and for easier access to the specimens.


Fastovsky D.E.,University of Rhode Island | Weishampel D.B.,Johns Hopkins University | Watabe M.,Hayashibara Museum of Natural science | Barsbold R.,Mongolian Academy of science | And 2 more authors.
Journal of Paleontology | Year: 2011

A remarkable specimen of the small neoceratopsian dinosaur Protoceratops andrewsi (Late Cretaceous, Mongolia) reveals the first nest of this genus, complete with fifteen juveniles. The relatively large size of the individuals and their advanced state of development suggests the possibility that Protoceratops juveniles remained and grew in their nests during at least the early stages of postnatal development. The nest further implies that parental care and sociality are phylogenetically basal behaviors in Ceratopsia. Finally, it reaffirms the conclusion that Protoceratops lived (and died) in the sandy aeolian dune fields of the central Asian craton. © 2011 The Paleontological Society.


Hone D.W.E.,University of Bristol | Hone D.W.E.,Queen Mary, University of London | Farke A.A.,Raymond M. Alf Museum of Paleontology | Watabe M.,Hayashibara Museum of Natural science | And 2 more authors.
PLoS ONE | Year: 2014

Background: Monodominant bonebeds are a relatively common occurrence for non-avian dinosaurs, and have been used to infer associative, and potentially genuinely social, behavior. Previously known assemblages are characterized as either mixed size-classes (juvenile and adult-sized specimens together) or single size-classes of individuals (only juveniles or only adult-sized individuals within the assemblage). In the latter case, it is generally unknown if these kinds of sizesegregated aggregations characterize only a particular size stage or represent aggregations that happened at all size stages. Ceratopsians (''horned dinosaurs'') are known from both types of assemblages. Copyright:Methods/Principal Findings: Here we describe a new specimen of the ceratopsian dinosaur Protoceratops andrewsi, Granger and Gregory 1923 from Mongolia representing an aggregation of four mid-sized juvenile animals. In conjunction with existing specimens of groups of P. andrewsi that includes sizeclustered aggregations of young juveniles and adult-sized specimens, this new material provides evidence for some degree of size-clustered aggregation behaviour in Protoceratops throughout ontogeny. This continuity of size-segregated (and presumably age-clustered) aggregation is previously undocumented in nonavian dinosaurs.Conclusions: The juvenile group fills a key gap in the available information on aggregations in younger ceratopsians. Although we support the general hypothesis that many non-avian dinosaurs were gregarious and even social animals, we caution that evidence for sociality has been overstated and advocate a more conservative interpretation of some data of 'sociality' in dinosaurs. © 2014 Hone et al.


Takai M.,Kyoto University | Soe A.N.,Defence Service Academy | Maung M.,Magway University | Tsubamoto T.,Hayashibara Museum of Natural science | And 3 more authors.
Journal of Human Evolution | Year: 2015

Here we report two kinds of colobine fossils discovered from the latest Miocene/Early Pliocene Irrawaddy sediments of the Chaingzauk area, central Myanmar. A left mandibular corpus fragment preserving M1-3 is named as a new genus and species, Myanmarcolobus yawensis. Isolated upper (M1?) and lower (M2) molars are tentatively identified as Colobinae gen. et sp. indet. Although both forms are medium-sized colobines, they are quite different from each other in M2 morphology. The isolated teeth of the latter show typical colobine-type features, so it is difficult to identify their taxonomic position, whereas lower molars of Myanmarcolobus have unique features, such as a trapezoid-shaped long median lingual notch, a deeply concave median buccal cleft, a strongly developed mesiobuccal notch, and rather obliquely running transverse lophids. Compared with fossil and living Eurasian colobine genera, Myanmarcolobus is most similar in lower molar morphology to the Pliocene Dolichopithecus of Europe rather than to any Asian forms. In Dolichopithecus, however, the tooth size is much larger and the median lingual notch is mesiodistally much shorter than that of Myanmarcolobus. The discovery of Myanmarcolobus in central Myanmar is the oldest fossil record in Southeast Asia not only of colobine but also of cercopithecid monkeys and raises many questions regarding the evolutionary history of Asian colobine monkeys. © 2015 Elsevier Ltd.

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