The genus and species Yuyuanozoon magnificissimi gen. et sp. nov., a new fossil vetulicolian, is reported from the Early Cambrian Chengjiang Fauna in Yunnan of China. It has a bipartite body plan and five pairs of cha...The genus and species Yuyuanozoon magnificissimi gen. et sp. nov., a new fossil vetulicolian, is reported from the Early Cambrian Chengjiang Fauna in Yunnan of China. It has a bipartite body plan and five pairs of chain-formed gill sacs, showing the general characteristics of Ventulicolia. However, the exclusive 'atrial cavity' and external gill observed indicate that the new form is different from those previously described as vetulicolians, probably representing a lineage developed within deuterostomes and more primitive than urochordates.展开更多
The age assignment of cherts from ophiolitic/metamorphic complexes in northeastern Jiangxi is widely regarded as one of the crucial issues in the tectonic interpretation of South China. The ophiolitic and metamorphic ...The age assignment of cherts from ophiolitic/metamorphic complexes in northeastern Jiangxi is widely regarded as one of the crucial issues in the tectonic interpretation of South China. The ophiolitic and metamorphic complexes in northeastern Jiangxi have been traditionally regarded as part of the Proterozoic “Banxi (=Penhsi) Group” of the Jiangnan Uplift. However, recent reports of Late Paleozoic radiolarians from the rock complexes have caused some researchers to question the traditional interpretation of the tectonic and paleogeographic framework in the region; but other workers are suspicious about these findings. In order to test the validity of the putative radiolarians, we, an interdisciplinary study group including micropaleontologists, tectonic specialists and regional geologists, conducted field investigations and multiple re-samplings of the localities where the reported fossils were collected. Our comprehensive study shows that the chert of the ophiolitic complex and the associated low-grade metamorphic slate yield Mesoproterozoic and Neoproterozoic acritarchs, confirming the traditional view of their age assignment (Proterozoic); on the other hand, no recognizable radiolarian fossils have been discovered therein, thus raising questions about the recently published result of Paleozoic radiolarian findings. Probable causes for the putative radiolarian findings are thus discussed herein. Geochemical characteristics indicate that the chert sedimentation most probably occurred under a continental margin setting.展开更多
The mitochondrial 16S rDNA sequences of 40species of cheilostome bryozoans including those of 24species newly determined were used to reconstruct thephylogenetic tree using neighboring-joining andmaximum-parsi- mony m...The mitochondrial 16S rDNA sequences of 40species of cheilostome bryozoans including those of 24species newly determined were used to reconstruct thephylogenetic tree using neighboring-joining andmaximum-parsi- mony methods. By applying molecularclock technique on the basis of the appropriate phylogenyand the fossil record, the divergence times of the two maincheilostome groups, Anasca and Ascophora sensu stricto,were estimated. The results show that the molecularphylogeny of the higher taxonomic groups (superfamilies andhigher taxa) of cheilostome bryozoans is mostly in conflictwith the morphology-based phylogenetic trees; thedivergence of the extant groups of Anasca and those ofAscophora sensu stricto is estimated to have happened about263 Ma (Permian Guadalupian Epoch) and 183 Ma (EarlyJurassic), respectively.展开更多
Abundant and well-preserved organic-walled microfossils including acanthomorphic acritarchs have been found in Mesoproterozoic Beidajian Formation in the Yongji area of Shanxi Province, North China. The morphological ...Abundant and well-preserved organic-walled microfossils including acanthomorphic acritarchs have been found in Mesoproterozoic Beidajian Formation in the Yongji area of Shanxi Province, North China. The morphological and ultrastructural features of these acanthomorphic acri-tarchs resemble living dinoflagellates (e.g. double-walled and polygonal structures), which leads to the interpretation of these fossils as probably the oldest dinoflagellates. The detec-tion of dinosterane, a dinoflagellate biomarker, from pyro-lytic product of these fossils further supports the morpho-logical inference. This finding is consistent with molecular clock estimate that dinoflagellates may have diverged 700 to 900 million years (Ma) before previously known fossil re-cord.展开更多
Marine invertebrate animal embryos and their early developmental products are of great significance to the study of taxonomy and phylogeny of early animals. A great number of phosphatized globular fossils were collect...Marine invertebrate animal embryos and their early developmental products are of great significance to the study of taxonomy and phylogeny of early animals. A great number of phosphatized globular fossils were collected fromthe early Cambrian Kuanchuanpu Member (upper Dengying Formation), southern Shaanxi, and a nearly complete develo-pmental sequence—from a fertilized egg, via blastodisc formation, blastula development, blastodisc enlargement toward gastrulae, to tissue differentiation—can be discerned in this collection. This discovery provides unmatchable material for studies on the origin, taxonomy, radiation, and ontogeny of early metazoans.展开更多
Abundant well-preserved large articulated sponge fossils and isolated spicules have been reported from the Early Cambrian Hetang Formation, southern Anhui Province. This unique epifaunal fossil assemblage dominated by...Abundant well-preserved large articulated sponge fossils and isolated spicules have been reported from the Early Cambrian Hetang Formation, southern Anhui Province. This unique epifaunal fossil assemblage dominated by articulated sponge fossils is called the Xidi Sponge Fauna. The sponge fauna lived in a quiet oxygenic environment be- low the storm wave base. Bloom of phytoplankton and rapid sedimentation rate resulted in the deposition of the black shales. Sufficient food supply, lack of other competitors, abundant ecological niches, and demand for oxygen during early Cambrian were in favor of the diversification and evo- lution of large sponges in the Early Cambrian.展开更多
Newly discovered marine dinoflagellates from the lower-middle parts of the Lower Cretaceous Muling Formation of the Jixi Basin, eastern Heilongjiang Province, China, were identified as Circulodinium cingulatum He et a...Newly discovered marine dinoflagellates from the lower-middle parts of the Lower Cretaceous Muling Formation of the Jixi Basin, eastern Heilongjiang Province, China, were identified as Circulodinium cingulatum He et al., C. attadalicum (Cookson et Eisenack) Helby, Palaeoperidinium cretaceum Pocock, Oligosphaeridium totum Brideaux and Sentusidinium sp. Most of these species are distributed in the marine Lower Cretaceous strata of Europe, North America, Africa, Australia and Asia. It demonstrates that a transgression occurred in eastern Heilongjiang Province during the deposition of the Muling Formation, which was previously considered to be a coal-bearing continental stratigraphic unit. The marine dinoflagellates indicated that the Muling Formation is Barremian in age. The Palaeogeographic framework of eastern Heilongjiang Province in Late Mesozoic era should be rebuilt through systematic facies analyses of the marine, paralic and terrestrial deposits.展开更多
The extraordinarily preserved, diverse arthropod fauna from the Lower Cambrian Maotianshan shale,central Yunnan (southwest China), represents different evolutionary stages stepping from stem lineages towards crown art...The extraordinarily preserved, diverse arthropod fauna from the Lower Cambrian Maotianshan shale,central Yunnan (southwest China), represents different evolutionary stages stepping from stem lineages towards crown arthropods (also called euarthropods), which makes this fauna extremely significant for discussion of the origin and early diversification of the arthropods. Anatomical analyses of the Maotianshan shale arthropods strongly indicate that the origin of crown arthropods involved three major evolutionary events, arthrodisation, arthropodisation and cephalization. We try to explore possible evolutionary changes of the developmental mechanism that may have underlain origins of euarthropod appendage and head. Fossil evidence suggests that the formation of a jointed limb known as arthropodisation and formation of multi-segmented head (called cephalization), which characterize euarthropods, is an event after arthrodisation characterized with the formation of segmented-exoskeleton and the joint membrane between tergites.We propose that the Hox complex was already operating at least as early as in the Early Cambrian and is responsible for the formation of the joint membrane between two semgents through Hox gene regulation along the D-V and P-D axis.Fossil evidence indicates that the head in ground state of arthropods consists only of two segments, an ocular and an antennal one. The formation of multiple segmented,euarthropod head (called syncephalon) from the two-segmented head was a separate event, which is called cephalization. Presence of the Hox gene head expression domain and change of developmental mechanism in head segments might be responsible for the formation of the syncephalon and this event has been broadly finished in the Early Cambrian arthropods. The post-oral limbs in the early syncephalons as evidenced from the Lower Cambrian Maotianshan shale arthropods however were almost identical to those in trunk.Therefore we proposed that the Hox genes specifiedexpression in individual segment was a late evolutionary step postdating the formation of syncephalon.展开更多
Nystroemia reniformis (Kawasaki) comb. nov. is proposed based on specimens showing organic connections between Chiropteris reniformis Kawasaki and Nystroemia pectiniformis Halle from the Lower Permian of Dengfeng in H...Nystroemia reniformis (Kawasaki) comb. nov. is proposed based on specimens showing organic connections between Chiropteris reniformis Kawasaki and Nystroemia pectiniformis Halle from the Lower Permian of Dengfeng in Henan. Vegetative leaf has a long petiole, reniformed, cordate at the base, entire or slightly undulate at the margin; veins are fine, bifurcating repeatedly and finally becoming reticulate and forming polygonal or rhomboidal meshes. Fertile shoot arises from bract axils. The form of the bract is identical to that of a vegetative leaf. Ovuliferous organ arises from the axil of leafy organ, or in other case, both ovuliferous and leafy organs irregularly arise from the axis of the fertile shoot respectively. Numerous bicornute platyspermic seeds are arranged in two rows, obconical, with micropyle pointing upwards. It may represent a new extinct gymnosperms.展开更多
基金supported by the National Natural Science Foundation of China(Grants 40073007,40173002,40232020)the Natural Scienee Foundation of Yunnan Province(Grant 97D007Z)
文摘The genus and species Yuyuanozoon magnificissimi gen. et sp. nov., a new fossil vetulicolian, is reported from the Early Cambrian Chengjiang Fauna in Yunnan of China. It has a bipartite body plan and five pairs of chain-formed gill sacs, showing the general characteristics of Ventulicolia. However, the exclusive 'atrial cavity' and external gill observed indicate that the new form is different from those previously described as vetulicolians, probably representing a lineage developed within deuterostomes and more primitive than urochordates.
基金support from the National Natural Science Foundation of China(Grant 40172004)Chinese Academy of Sciences(Grant KZCX2-SW-129).
文摘The age assignment of cherts from ophiolitic/metamorphic complexes in northeastern Jiangxi is widely regarded as one of the crucial issues in the tectonic interpretation of South China. The ophiolitic and metamorphic complexes in northeastern Jiangxi have been traditionally regarded as part of the Proterozoic “Banxi (=Penhsi) Group” of the Jiangnan Uplift. However, recent reports of Late Paleozoic radiolarians from the rock complexes have caused some researchers to question the traditional interpretation of the tectonic and paleogeographic framework in the region; but other workers are suspicious about these findings. In order to test the validity of the putative radiolarians, we, an interdisciplinary study group including micropaleontologists, tectonic specialists and regional geologists, conducted field investigations and multiple re-samplings of the localities where the reported fossils were collected. Our comprehensive study shows that the chert of the ophiolitic complex and the associated low-grade metamorphic slate yield Mesoproterozoic and Neoproterozoic acritarchs, confirming the traditional view of their age assignment (Proterozoic); on the other hand, no recognizable radiolarian fossils have been discovered therein, thus raising questions about the recently published result of Paleozoic radiolarian findings. Probable causes for the putative radiolarian findings are thus discussed herein. Geochemical characteristics indicate that the chert sedimentation most probably occurred under a continental margin setting.
基金supported by the National Natural Science Foundation of China(Grant Nos.94725204&40202001)Ministry of Science and Techonology(Grant No.G2000077702)State Key Laboratory of Palaeobiology and Straitigraphy,Nanjing Institute of Geology and Palaeontology,the Chinese Academy of Sciences(Grant No.013115).
文摘The mitochondrial 16S rDNA sequences of 40species of cheilostome bryozoans including those of 24species newly determined were used to reconstruct thephylogenetic tree using neighboring-joining andmaximum-parsi- mony methods. By applying molecularclock technique on the basis of the appropriate phylogenyand the fossil record, the divergence times of the two maincheilostome groups, Anasca and Ascophora sensu stricto,were estimated. The results show that the molecularphylogeny of the higher taxonomic groups (superfamilies andhigher taxa) of cheilostome bryozoans is mostly in conflictwith the morphology-based phylogenetic trees; thedivergence of the extant groups of Anasca and those ofAscophora sensu stricto is estimated to have happened about263 Ma (Permian Guadalupian Epoch) and 183 Ma (EarlyJurassic), respectively.
基金the State Key Laboratory of Palaeobiology and Stratigraphy(Nanjing institute of Geology and Palaeontology,CAS)(Grant No.053109)the National Natural Sciences Foundation of China(Grant Nos.40162002.40372023.40232020)+1 种基金the Foundation of the Key and Basic Project of Science and Technology of Guizhou(Grant No.2002-309) the Earlyand Special Project of Key Basic Project of the Ministry of Science andTechnology.China(Grant No.2002,CCC02600).
基金supported by the National N atural Science Foundation of China(Grant No.40472003)the Ministry of Science and Technology of China(Grant Nos.G2000077701 and 2003CB7 16805)the Chinese Academy of Sciences(Grant No,KZCX3-SW-141).
文摘Abundant and well-preserved organic-walled microfossils including acanthomorphic acritarchs have been found in Mesoproterozoic Beidajian Formation in the Yongji area of Shanxi Province, North China. The morphological and ultrastructural features of these acanthomorphic acri-tarchs resemble living dinoflagellates (e.g. double-walled and polygonal structures), which leads to the interpretation of these fossils as probably the oldest dinoflagellates. The detec-tion of dinosterane, a dinoflagellate biomarker, from pyro-lytic product of these fossils further supports the morpho-logical inference. This finding is consistent with molecular clock estimate that dinoflagellates may have diverged 700 to 900 million years (Ma) before previously known fossil re-cord.
文摘Marine invertebrate animal embryos and their early developmental products are of great significance to the study of taxonomy and phylogeny of early animals. A great number of phosphatized globular fossils were collected fromthe early Cambrian Kuanchuanpu Member (upper Dengying Formation), southern Shaanxi, and a nearly complete develo-pmental sequence—from a fertilized egg, via blastodisc formation, blastula development, blastodisc enlargement toward gastrulae, to tissue differentiation—can be discerned in this collection. This discovery provides unmatchable material for studies on the origin, taxonomy, radiation, and ontogeny of early metazoans.
文摘Abundant well-preserved large articulated sponge fossils and isolated spicules have been reported from the Early Cambrian Hetang Formation, southern Anhui Province. This unique epifaunal fossil assemblage dominated by articulated sponge fossils is called the Xidi Sponge Fauna. The sponge fauna lived in a quiet oxygenic environment be- low the storm wave base. Bloom of phytoplankton and rapid sedimentation rate resulted in the deposition of the black shales. Sufficient food supply, lack of other competitors, abundant ecological niches, and demand for oxygen during early Cambrian were in favor of the diversification and evo- lution of large sponges in the Early Cambrian.
基金supported by the Pilot Project of Knowledge Innovation Program of the Chinese Academy of Sciences(Grant No.KZCX2-114)the National Natural Science Foundation of China(Grant No.40072004).
文摘Newly discovered marine dinoflagellates from the lower-middle parts of the Lower Cretaceous Muling Formation of the Jixi Basin, eastern Heilongjiang Province, China, were identified as Circulodinium cingulatum He et al., C. attadalicum (Cookson et Eisenack) Helby, Palaeoperidinium cretaceum Pocock, Oligosphaeridium totum Brideaux and Sentusidinium sp. Most of these species are distributed in the marine Lower Cretaceous strata of Europe, North America, Africa, Australia and Asia. It demonstrates that a transgression occurred in eastern Heilongjiang Province during the deposition of the Muling Formation, which was previously considered to be a coal-bearing continental stratigraphic unit. The marine dinoflagellates indicated that the Muling Formation is Barremian in age. The Palaeogeographic framework of eastern Heilongjiang Province in Late Mesozoic era should be rebuilt through systematic facies analyses of the marine, paralic and terrestrial deposits.
文摘The extraordinarily preserved, diverse arthropod fauna from the Lower Cambrian Maotianshan shale,central Yunnan (southwest China), represents different evolutionary stages stepping from stem lineages towards crown arthropods (also called euarthropods), which makes this fauna extremely significant for discussion of the origin and early diversification of the arthropods. Anatomical analyses of the Maotianshan shale arthropods strongly indicate that the origin of crown arthropods involved three major evolutionary events, arthrodisation, arthropodisation and cephalization. We try to explore possible evolutionary changes of the developmental mechanism that may have underlain origins of euarthropod appendage and head. Fossil evidence suggests that the formation of a jointed limb known as arthropodisation and formation of multi-segmented head (called cephalization), which characterize euarthropods, is an event after arthrodisation characterized with the formation of segmented-exoskeleton and the joint membrane between tergites.We propose that the Hox complex was already operating at least as early as in the Early Cambrian and is responsible for the formation of the joint membrane between two semgents through Hox gene regulation along the D-V and P-D axis.Fossil evidence indicates that the head in ground state of arthropods consists only of two segments, an ocular and an antennal one. The formation of multiple segmented,euarthropod head (called syncephalon) from the two-segmented head was a separate event, which is called cephalization. Presence of the Hox gene head expression domain and change of developmental mechanism in head segments might be responsible for the formation of the syncephalon and this event has been broadly finished in the Early Cambrian arthropods. The post-oral limbs in the early syncephalons as evidenced from the Lower Cambrian Maotianshan shale arthropods however were almost identical to those in trunk.Therefore we proposed that the Hox genes specifiedexpression in individual segment was a late evolutionary step postdating the formation of syncephalon.
基金supported by the National Natural Science Foundation of China(Grant No.40102002)KZCX2-SW-130 CAS,SEPP(Grant No.000206)CASthe State Key Laboratory of Palaeobiology and Stratigraphy NIGPAS(Grant No.013109).
文摘Nystroemia reniformis (Kawasaki) comb. nov. is proposed based on specimens showing organic connections between Chiropteris reniformis Kawasaki and Nystroemia pectiniformis Halle from the Lower Permian of Dengfeng in Henan. Vegetative leaf has a long petiole, reniformed, cordate at the base, entire or slightly undulate at the margin; veins are fine, bifurcating repeatedly and finally becoming reticulate and forming polygonal or rhomboidal meshes. Fertile shoot arises from bract axils. The form of the bract is identical to that of a vegetative leaf. Ovuliferous organ arises from the axil of leafy organ, or in other case, both ovuliferous and leafy organs irregularly arise from the axis of the fertile shoot respectively. Numerous bicornute platyspermic seeds are arranged in two rows, obconical, with micropyle pointing upwards. It may represent a new extinct gymnosperms.
