35 research outputs found

    The oldest fossil forest in Japan discovered from the Upper Triassic Nariwa Group, Okayama Prefecture, SW Japan -Implication for reconstruction of depositional environment and paleovegetation-

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    Erect fossil stumps were found from the outcrop of the Upper Triassic Hinabata Formation, the uppermost part of the Nariwa Group at Hinabata, Nariwa-cho,Takahashi City, Okayama Prefecture, SW Japan. They are evidence of the oldest fossil forest in Japan. The Upper Triassic Nariwa Group is mostly composed of non-marine deposits except the marine Jito Formation and characterized by the abundance in plant fossils. The marine Jito Formation is characterized by occurrence of Norian Monotis ochotica. On the basis of detailed observation of the occurrence of erect fossil stumps, as well as sedimentary facies of fossil-bearing unit, the fossil forest was interpreted to have grown on the top of the natural-levee units. One of the erect fossil stumps was identified as Xenoxylon sp

    Non-calcareous beachrock found in Akagurisaki, Ohi Town, Fukui Prefecture

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    Beachrock which was formed about 0.5 meter higher than high tide is found in Akagurisaki, Ohi Town, Fukui Prefecture. The outcrops always get wet by spring water. The sediments are composed of well sorted rounded gravels and sands but calcareous shell is not found at all. Intergranular space is occupied by white amorphous cement. Magnesium and silicon rich composition of the cement is obtained by EPMA analysis. There is a conjecture that the magnesium rich cement was precipitated in spite of solution of calcareous shell under saturated state by spring water, because calcium has a higher tendency to ionize than magnesium

    A New Sinamiin Fish (Actinopterygii) from the Early Cretaceous of Thailand: Implications on the Evolutionary History of the Amiid Lineage

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    The Sinamiidae are a family of halecomorph fishes (Holostei) stratigraphically limited to the Lower Cretaceous and confined to East Asia. The first species of sinamiids were discovered in China, and then new occurrences were recorded in Thailand and Japan. The three recognized genera, Sinamia, Siamamia and Ikechaoamia, are notably characterized by an unpaired parietal. Here, we describe a new genus and species of sinamiid based on material from the Aptian Khok Kruat Formation of Ban Krok Duean Ha, Nakhon Ratchasima, Thailand. The new taxon known from preserved specimens in 3D is characterized by four pairs of extrascapular and tall cylindrical teeth with a conical enamel stalk topped by an arrowhead-shaped acrodine cap, among other characters. A phylogenetic analysis of the halecomorph fishes shows that the new taxon is the sister of the other Thai species, Siamamia naga, and that the two are grouped with two Chinese genera in a strongly supported clade, the Sinamiinae. This subfamily is here grouped with the Amiinae that contained the extant Amia. This new discovery is a clue that Southeast Asia may have been a center of diversification for this fish clade, and the phylogenetic analysis reveals that amiines may have originated somewhere in Asia during the Cretaceous before they spread throughout the northern hemisphere

    Molecular phylogenetic study of the tribe Tropidieae (Orchidaceae, Epidendroideae) with taxonomic and evolutionary implications

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    The orchid tribe Tropidieae comprises three genera, Tropidia, Corymborkis and Kalimantanorchis. There are three fully mycoheterotrophic species within Tropidieae: Tropidia saprophytica, T. connata and Kalimantanorchis nagamasui. A previous phylogenetic study of K. nagamasui, based only on plastid matK data, placed K. nagamasui outside the clade of Tropidia and Corymborkis without support. In this study, we performed phylogenetic analyses using a nuclear ribosomal DNA spacer (ITS1-5.8S-ITS2), a low-copy nuclear coding gene (Xdh) and a mitochondrial intron (nad1b-c intron) to study the phylogenetic relationships within Tropidieae. We included six photosynthetic and all three fully mycoheterotrophic Tropidieae species. The resulting phylogenetic trees placed these fully mycoheterotrophic species inside the Tropidia clade with high support. In our trees, these three species do not form a monophyletic group together, because the photosynthetic T. graminea is nested amongst them. Our results also suggest that the loss of photosynthetic ability occurred at least twice in Tropidia

    Molecular phylogenetic study of the tribe Tropidieae (Orchidaceae, Epidendroideae) with taxonomic and evolutionary implications

    No full text
    The orchid tribe Tropidieae comprises three genera, Tropidia, Corymborkis and Kalimantanorchis. There are three fully mycoheterotrophic species within Tropidieae: Tropidia saprophytica, T. connata and Kalimantanorchis nagamasui. A previous phylogenetic study of K. nagamasui, based only on plastid matK data, placed K. nagamasui outside the clade of Tropidia and Corymborkis without support. In this study, we performed phylogenetic analyses using a nuclear ribosomal DNA spacer (ITS1-5.8S-ITS2), a low-copy nuclear coding gene (Xdh) and a mitochondrial intron (nad1b-c intron) to study the phylogenetic relationships within Tropidieae. We included six photosynthetic and all three fully mycoheterotrophic Tropidieae species. The resulting phylogenetic trees placed these fully mycoheterotrophic species inside the Tropidia clade with high support. In our trees, these three species do not form a monophyletic group together, because the photosynthetic T. graminea is nested amongst them. Our results also suggest that the loss of photosynthetic ability occurred at least twice in Tropidia

    Molecular phylogenetic study of the tribe Tropidieae (Orchidaceae, Epidendroideae) with taxonomic and evolutionary implications

    No full text
    The orchid tribe Tropidieae comprises three genera, Tropidia, Corymborkis and Kalimantanorchis. There are three fully mycoheterotrophic species within Tropidieae: Tropidia saprophytica, T. connata and Kalimantanorchis nagamasui. A previous phylogenetic study of K. nagamasui, based only on plastid matK data, placed K. nagamasui outside the clade of Tropidia and Corymborkis without support. In this study, we performed phylogenetic analyses using a nuclear ribosomal DNA spacer (ITS1-5.8S-ITS2), a low-copy nuclear coding gene (Xdh) and a mitochondrial intron (nad1b-c intron) to study the phylogenetic relationships within Tropidieae. We included six photosynthetic and all three fully mycoheterotrophic Tropidieae species. The resulting phylogenetic trees placed these fully mycoheterotrophic species inside the Tropidia clade with high support. In our trees, these three species do not form a monophyletic group together, because the photosynthetic T. graminea is nested amongst them. Our results also suggest that the loss of photosynthetic ability occurred at least twice in Tropidia
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