![]() glyptostroboides trees planted in Secrest Arboretum in northeast Ohio, USA-shows negative correlations with maximum monthly temperatures: with the strongest relationship with February and the warm months of June and July, all significant at the 99% confidence levels. An annual ring-width chronology-spanning 1955 to 2010 and based on a stand of 19 M. Analyzing the climate response of a transplanted stand of the trees can give insights into their physiological plasticity, into their use in restoration and reforestation, as well as into interpreting the environmental conditions of the geologic past from fossil Metasequoia. ![]() Metasequoia glyptostroboides, a deciduous gymnosperm, also known as dawn redwood, was thought to be extinct until living members of the species were found in China in 1943. Furthermore, elements of the polar broad-leaved deciduous forests appear to have occupied northern Europe and extended into the Ural Mountains and, despite the functionality of the lowland corridors between Europe and the West Siberian Plain, floristic exchange was not pronounced until Miocene time when climate became cooler and drier, signaling the onset of the evolution and development of boreal ecosystems in Europe and the West Siberian Plain. The results of this multivariate analysis indicate floristic exchange between Europe and the West Siberian Plain was not prevalent, but much more pronounced between the West Siberian Plain and the Ural Mountains during the Rupelian and Chattian. The fossil wood and macrofossil taxa are compared to European and other West Siberian Plain floras of similar age to understand the spatial and temporal relationships between these floras. The Kompasky Bor flora is important because it is the northernmost Chattian macroflora in the West Siberian Plain so far known and provides constraints on the timing and record of plant taxa migrations between Europe and the West Siberian Plain during the late Paleogene and the early Neogene. and three new species are established: Thujopsoxylon schneiderianum sp. Twenty conifer and angiosperm wood taxa are described and a new fossil wood genus Thujopsoxylon gen. In this study, we describe the fossil wood flora from the Chattian (late Oligocene) and Aquitanian (early Miocene) deposits that crop out on the Tym River at Kompasky Bor, Russia. The remarkable morphological stasis observed in Metasequoia demonstrates that the genus has remained unchanged, at least morphologically, since the early Late Cretaceous. occidentalis are indistinguishable from the living species. With few exceptions, the bulk of the Metasequoia fossils described in the literature indicate that the fossils assigned to M. The pronounced reduction in distribution during the Miocene appears to be coupled with increasing global aridity and cooling and increased competition for resources and habitat from representatives of the Pinaceae. Following the apparent early Pleistocene extinction, Metasequoia re-appeared in southeastern China. Metasequoia persisted in western Siberia and the Canadian Arctic until late Pliocene time, and in western Georgia and Japan until the late Pliocene-early Pleistocene. Of particular interest is the apparent lack of Metasequoia fossils in Europe despite the presence of two land bridges linking North America and Europe throughout the early Tertiary and the drying of the Turgai Straits that separated eastern and western Asia up until Oligocene time. More importantly, the distribution of Metasequoia indicates that the genus grew and reproduced under a diverse range of climatic and environmental conditions throughout geologic time, including the cold and unique lighting conditions of the polar latitudes. By the early Tertiary, the distribution patterns do not appear to have changed considerably from that seen during the Late Cretaceous, except that Metasequoia became a dominant constituent of the polar Broad-leaved Deciduous Forests. However, if the inter-continental exchange of the early representatives of this genus occurred prior to the establishment of Beringia, migration would have still been possible across the Spitsbergen Corridor, which was functional during the Early Cretaceous. Exchange of Metasequoia between Asia and North America probably occurred across Beringia, which had become functional at the Albian-Cenomanian boundary (ca. ![]() The genus first appears in Cenomanian age deposits from western Canada, Alaska and the Arkagala and Koylma River basins in Russia and indicates that Metasequoia had achieved a wide distribution early in its evolutionary history. The fossil record of Metasequoia Miki is extensive and demonstrates that the genus was widely distributed throughout North America and Eurasia from the early Late Cretaceous to the Plio-Pleistocene.
0 Comments
Leave a Reply. |