Two records of the crust laminae from the Marcus-Wake Seamounts and the Magellan Seamount were biostratigraphically studied. Based on biological imprints of the calcareous nannofossils, the geological ages of the two ...Two records of the crust laminae from the Marcus-Wake Seamounts and the Magellan Seamount were biostratigraphically studied. Based on biological imprints of the calcareous nannofossils, the geological ages of the two records were determined, with CM1D03 from the Marcus-Wake Seamounts being of late Paleocene to Pleistocene and CM3D06 from the Magellan Seamount of Late Cretaceous （more than 70.0 Ma）. There are the obvious temporal-spatial differences in the initial formation period and enrichment characteristics of the cobalt-rich crusts of the two seamount chains and differences in the combination and distribution of microfossils in the inner crust layers between the seamounts. These differences are due to the adaptabilities of oceanic species in different environments. Ecological research was carried out in terms of population size of the calcareous nannofossi｜s preserved in the crustal layers to discern the relation of the geological events at the Eocene-Oligocene （E/O） tran- sition. The results show the transitions and recombination of species in the biotic community during the E/O transition obvi- ously corresponded to 25 mm depth in the CM1D03 crust and 58 mm depth in the CM3D06 crust. The changes in biological species and the formation of particular ecological structures indicate the adaptive response of the paleo-biological community in the western Pacific Ocean to the global cold-climate events and the close correlation between the formation of the crust and the global climate change.展开更多
Here we describe tHuashancyprinus robustispinus, gen. et sp. nov, a fossil cyprinin fish from the Oligocene of Ningming Ba- sin, Guangxi, South China. It differs from all other cyprinin fishes in the following apomorp...Here we describe tHuashancyprinus robustispinus, gen. et sp. nov, a fossil cyprinin fish from the Oligocene of Ningming Ba- sin, Guangxi, South China. It differs from all other cyprinin fishes in the following apomorphic characters： extremely robust last unbranched dorsal and anal fin rays with very fine serrations along posterior edge, the crowns of pharyngeal teeth A2 and A3 with a number of deep grooves on the lateral wall, rather large A3, and relatively deep infraorbital 2. Among the members of the Tribe Cyprinini sensu stricto, it mostly resembles the extant genus Cyprinus, particularly to species Cyprinus micristius and C. fuxianensis, which are restricted to Yunnan, southwestern China. The discovery of the cyprinin Huashancyprinus from southern China, along with the previously known late Eocene tCyprinus maomingensis, indicates an early branching of the Cyprininae （Cyprinidae） in this area.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.41076072 and 40676025)
文摘Two records of the crust laminae from the Marcus-Wake Seamounts and the Magellan Seamount were biostratigraphically studied. Based on biological imprints of the calcareous nannofossils, the geological ages of the two records were determined, with CM1D03 from the Marcus-Wake Seamounts being of late Paleocene to Pleistocene and CM3D06 from the Magellan Seamount of Late Cretaceous （more than 70.0 Ma）. There are the obvious temporal-spatial differences in the initial formation period and enrichment characteristics of the cobalt-rich crusts of the two seamount chains and differences in the combination and distribution of microfossils in the inner crust layers between the seamounts. These differences are due to the adaptabilities of oceanic species in different environments. Ecological research was carried out in terms of population size of the calcareous nannofossi｜s preserved in the crustal layers to discern the relation of the geological events at the Eocene-Oligocene （E/O） tran- sition. The results show the transitions and recombination of species in the biotic community during the E/O transition obvi- ously corresponded to 25 mm depth in the CM1D03 crust and 58 mm depth in the CM3D06 crust. The changes in biological species and the formation of particular ecological structures indicate the adaptive response of the paleo-biological community in the western Pacific Ocean to the global cold-climate events and the close correlation between the formation of the crust and the global climate change.
基金supported by National Natural Science Foundation of China(Grant Nos.40432003 and 40662001)State Key Laboratory of Palaeobiology and Stratigraphy(Nanjing Institute of Geology and Palaeontology,CAS)(Grant No.063106)Cypriniformes Tree of life under the U.S.National Science Foundation to R.Mayden(Grant No. EFO431326),and the Culture Department of Guangxi Zhuang Autonomous Region
文摘Here we describe tHuashancyprinus robustispinus, gen. et sp. nov, a fossil cyprinin fish from the Oligocene of Ningming Ba- sin, Guangxi, South China. It differs from all other cyprinin fishes in the following apomorphic characters： extremely robust last unbranched dorsal and anal fin rays with very fine serrations along posterior edge, the crowns of pharyngeal teeth A2 and A3 with a number of deep grooves on the lateral wall, rather large A3, and relatively deep infraorbital 2. Among the members of the Tribe Cyprinini sensu stricto, it mostly resembles the extant genus Cyprinus, particularly to species Cyprinus micristius and C. fuxianensis, which are restricted to Yunnan, southwestern China. The discovery of the cyprinin Huashancyprinus from southern China, along with the previously known late Eocene tCyprinus maomingensis, indicates an early branching of the Cyprininae （Cyprinidae） in this area.
