The fossil trunks and rhizomes of Osmundaceae provide important information about its evolutionary history.Due to limited records of the Mesozoic trunks and rhizomes in the Eurasia of the Northern Hemisphere,our under...The fossil trunks and rhizomes of Osmundaceae provide important information about its evolutionary history.Due to limited records of the Mesozoic trunks and rhizomes in the Eurasia of the Northern Hemisphere,our understanding on the fossil diversity of the Osmundaceae is hindered.Two new species of the Osmundaceae trunks,Osmundacaulis asiatica sp.nov.and Osmundacaulis sinica sp.nov.representing the first discovery of the Mesozoic tree fern genus Osmundacaulis in Eurasia,are described from Wudalianchi and Qiqihar,Heilongjiang Province,Northeast China,which enriches the plant diversity of the Osmundaceae in the Eurasia,and provides vital evidence for studying the distribution,radiation and evolution of the genus during the Cretaceous.The fossil records suggest that Osmundacaulis species may have evolved from a common ancestor,which first appeared in the Australian portion of Pangaea,and then spread to ancient northern North America and ancient East Asia.Since then,they developed into different species through their own evolutionary lines.The Chinese species have a special local feature that the outer cortex is thicker than the inner cortex,in contrast with reported Osmundacaulis species having thinner outer cortex and thicker inner cortex.Long-term geographic isolation may have led to the radiation of diverse Osmundacaulis species and the appearance of region-specific features,such as the thick outer cortex and the thin inner cortex of the Chinese species.Among all reported Osmundacaulis species,the two new species found in China,O.nerii from the Jurassic of Australia and the O.lemonii from the Jurassic of the USA,have special groups of mucilage-sacs inside sclerenchyma ring of petiole base.Mucilage sacs probably originated independently among taxonomic groups,representing convergent adaptations to similar habitats,rather than indicating genetic inheritance from a common ancestor.展开更多
Permineralized osmundaceous rhizome with anatomical and phylogenetic information plays a significant role in understanding the origin,evolution,and diversity variation of the fern family Osmundaceae in geological hist...Permineralized osmundaceous rhizome with anatomical and phylogenetic information plays a significant role in understanding the origin,evolution,and diversity variation of the fern family Osmundaceae in geological history.The northern Hebei and western Liaoning region is one of the most important fossil localities for the Jurassic osmundaceous rhizome fossils in the Northern Hemisphere;however,the diversity character of osmundaceous rhizome fossil remains poorly known.A new structurally preserved fern rhizome species,Ashicaulis wangii sp.nov.,is described from the Middle Jurassic Tiaojishan Formation in Beipiao City,Liaoning Province,northeastern China.The rhizome is composed of heterogeneous pith,an ectophloic–dictyoxylic siphonostele,a two–layered cortex,and a mantle of adventitious roots and petiole bases.The xylem cylinder,with complete leaf gaps,consists of 15–17 xylem strands.The petiole base is characterized by a heterogeneous sclerotic ring and numerous sclerenchyma masses in the petiolar cortex.Among five known Ashicaulis species with heterogeneous sclerotic ring,four of them are documented from China.Therefore,osmundaceous rhizome fossils from China show endemic anatomical characteristics and significances for palaeobiogeography.Comparisons of anatomical features suggest that A.wangii sp.nov.bears close similarities to Osmunda pluma Miller from the Paleocene of Dakota,USA.Fossil species of A.wangii provides new evidence for further understanding the species diversity of osmundaceous rhizome fossil in China and in the Northern Hemisphere,and contributes to exploring the macroevolution process of the Mesozoic osmundaceous plants.展开更多
The family Osmundaceae receives much concern of palaeobotanists for its peculiar sporangia and phylogenetic relationship.Abundant osmundaceous fossils have been reported in China.So far,about 34 species ascribed to se...The family Osmundaceae receives much concern of palaeobotanists for its peculiar sporangia and phylogenetic relationship.Abundant osmundaceous fossils have been reported in China.So far,about 34 species ascribed to seven genera of Osmundaceae have been documented except for three morphogenera.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.31970234)the Ministry of Natural Resources,China(Grant No.12111300000018001)Key-Lab for Evolution of Past Life and Environment in Northeast Asia,Ministry of Education,China(Grant No.2018JDEPw001)。
文摘The fossil trunks and rhizomes of Osmundaceae provide important information about its evolutionary history.Due to limited records of the Mesozoic trunks and rhizomes in the Eurasia of the Northern Hemisphere,our understanding on the fossil diversity of the Osmundaceae is hindered.Two new species of the Osmundaceae trunks,Osmundacaulis asiatica sp.nov.and Osmundacaulis sinica sp.nov.representing the first discovery of the Mesozoic tree fern genus Osmundacaulis in Eurasia,are described from Wudalianchi and Qiqihar,Heilongjiang Province,Northeast China,which enriches the plant diversity of the Osmundaceae in the Eurasia,and provides vital evidence for studying the distribution,radiation and evolution of the genus during the Cretaceous.The fossil records suggest that Osmundacaulis species may have evolved from a common ancestor,which first appeared in the Australian portion of Pangaea,and then spread to ancient northern North America and ancient East Asia.Since then,they developed into different species through their own evolutionary lines.The Chinese species have a special local feature that the outer cortex is thicker than the inner cortex,in contrast with reported Osmundacaulis species having thinner outer cortex and thicker inner cortex.Long-term geographic isolation may have led to the radiation of diverse Osmundacaulis species and the appearance of region-specific features,such as the thick outer cortex and the thin inner cortex of the Chinese species.Among all reported Osmundacaulis species,the two new species found in China,O.nerii from the Jurassic of Australia and the O.lemonii from the Jurassic of the USA,have special groups of mucilage-sacs inside sclerenchyma ring of petiole base.Mucilage sacs probably originated independently among taxonomic groups,representing convergent adaptations to similar habitats,rather than indicating genetic inheritance from a common ancestor.
基金jointly supported by State Key Programme of Basic Research of Ministry of Science and Technology,China(Grant No.2012CB822003)the National Natural Science Foundation of China(Grant Nos.41272010,41302004&40972008)+4 种基金the Innovation Project of CAS(Grant No.KZCX-2-YW-154)the Team Program of Scientific Innovation and Interdisciplinary Cooperation of CASthe State Key Laboratory of Palaeobiology and Stratigraphy(Nanjing Institute of Geology and Palaeontology,CAS)(Grant No.133113)Science Research Project of Liaoning Provincial Education Department(Grant No.L2012391)the Doctoral Fund of Shenyang Normal University
文摘Permineralized osmundaceous rhizome with anatomical and phylogenetic information plays a significant role in understanding the origin,evolution,and diversity variation of the fern family Osmundaceae in geological history.The northern Hebei and western Liaoning region is one of the most important fossil localities for the Jurassic osmundaceous rhizome fossils in the Northern Hemisphere;however,the diversity character of osmundaceous rhizome fossil remains poorly known.A new structurally preserved fern rhizome species,Ashicaulis wangii sp.nov.,is described from the Middle Jurassic Tiaojishan Formation in Beipiao City,Liaoning Province,northeastern China.The rhizome is composed of heterogeneous pith,an ectophloic–dictyoxylic siphonostele,a two–layered cortex,and a mantle of adventitious roots and petiole bases.The xylem cylinder,with complete leaf gaps,consists of 15–17 xylem strands.The petiole base is characterized by a heterogeneous sclerotic ring and numerous sclerenchyma masses in the petiolar cortex.Among five known Ashicaulis species with heterogeneous sclerotic ring,four of them are documented from China.Therefore,osmundaceous rhizome fossils from China show endemic anatomical characteristics and significances for palaeobiogeography.Comparisons of anatomical features suggest that A.wangii sp.nov.bears close similarities to Osmunda pluma Miller from the Paleocene of Dakota,USA.Fossil species of A.wangii provides new evidence for further understanding the species diversity of osmundaceous rhizome fossil in China and in the Northern Hemisphere,and contributes to exploring the macroevolution process of the Mesozoic osmundaceous plants.
文摘The family Osmundaceae receives much concern of palaeobotanists for its peculiar sporangia and phylogenetic relationship.Abundant osmundaceous fossils have been reported in China.So far,about 34 species ascribed to seven genera of Osmundaceae have been documented except for three morphogenera.
