Plant communities of the geologic past can be reconstructed with high fidelity only if they were preserved in place in an instant in time. Here we report such a flora from an early Permian (ca. 298 Ma) ash-fall tuff in Inner Mongolia, a time interval and area where such information is filling a large gap of knowledge. About 1,000 m 2 of forest growing on peat could be reconstructed based on the actual location of individual plants. Tree ferns formed a lower canopy and either Cordaites , a coniferophyte, or Sigillaria , a lycopsid, were present as taller trees. Noeggerathiales, an enigmatic and extinct spore-bearing plant group of small trees, is represented by three species that have been found as nearly complete specimens and are presented in reconstructions in their plant community. Landscape heterogenity is apparent, including one site where Noeggerathiales are dominant. This peat-forming flora is also taxonomically distinct from those growing on clastic soils in the same area and during the same time interval. This Permian flora demonstrates both similarities and differences to floras of the same age in Europe and North America and confirms the distinct character of the Cathaysian floral realm. Therefore, this flora will serve as a baseline for the study of other fossil floras in East Asia and the early Permian globally that will be needed for a better understanding of paleoclimate evolution through time.
Metasequoia Miki 1941 was a prominent element of vegetation distributed in the high latitudes of Northern Hemisphere from the late Early Cretaceous to Miocene.However, at present this genus survived only in some mountain areas of Hubei, Hunan and Chongqing of China as a relict genus.Although the distribution of Metasequoia through geologic time have been studied in detail, the relationship between its distribution and paleoclimates remained unclear.In this paper, the potential migratory routes of Metasequoia are explained on the basis of the its fossil records plotted in the paleoclimate maps.It can be concluded that: 1) the Warm Temperate climate favored to the diffusion of Metasequoia, while the Arid climate curbs its migration; 2) with the global temperature decreased markedly since Pliocene, Metasequoia was forced to migrate to the south, and survived only in South China, under the Warm Temperate climate support.K e y w o r d s : Metasequoia, distribution, paleoclimate factors Р Е З Ю М Е Жан Й., Ван Ж.Ж.Историческое распространение Metasequoia по от но ше нию к палеоклиматическим факторам.Metasequoia Miki 1941 бы ла весьма значимым элементом растительного покрова, распространенным в высоких широтах Северного полушария с конца раннего мела до мио цена.Тем не менее, представители этого рода в настоящее время сохрани лись только в некоторых горных районах провинций Хубэй, Хунань и Чун цин в Китае как реликтовые растения.Хотя распространение Metasequoia в гео ло ги ческом времени было детально изучено в предыдущих исследова ниях, отношения между распространением рода и факторами палеоклима та оставались не ясными.В данной статье потенциальные миграционные мар шру ты Metasequoia прояснаются путем наложения местоположения най ден ных фоссилий Metasequoia на разработанные палеоклиматические кар ты.Полученные результаты позволяют сделать следующие выводы: 1) теп ло уме ренный климат благоприятствовал распространению Metasequoia, в то вре мя как засушливый климат сдерживал миграции рода; 2) по мере пони же ния глобальных температур в плиоцене Metasequoia мигрировала на юг и вы жила в настоящее время только в Южном Китае, в условиях теплоуме рен ного климата.
Significance There were two heterosporous lignophyte lineages of which only one, the seed plants, survived the Permian–Triassic mass extinction. Based on exceptionally complete fossil trees from a 300-My-old volcanic ash, the enigmatic Noeggerathiales are now recognized as belonging to the other lineage. They diversified alongside the primary seed plant radiation and constitute seed plants’ closest relatives. Noeggerathiales are reconstructed as members of a plexus of free-sporing woody plants called progymnosperms, extending their age range by 60 My. Following the origin of seed plants, progymnosperms were previously thought to have become gradually less abundant before dying out in Carboniferous. We show they diversified and evolved complex morphologies including cone-like structures from modified leaves before going extinct at the Permian–Triassic extinction.
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