Conodonts and fusulinids are the two most widely used biotic groups for subdividing and correlating Bashkirian and Moscovian strata. The definition of the base of the Global Moscovian Stage is undecided because there ...Conodonts and fusulinids are the two most widely used biotic groups for subdividing and correlating Bashkirian and Moscovian strata. The definition of the base of the Global Moscovian Stage is undecided because there are many disagreements among existing boundary definition proposals,each of which has disadvantages. Declinognathodus donetzianus is easily recognized but somewhat limited in its paleogeographic distribution. Idiognathoides postsulcatus is slightly more widespread, but it is less easily identified and its occurrences may be diachronous from region to region. Diplognathodus ellesmerensis is easily recognized and even more widespread, but it is usually rare and its ancestry is not adequately known. The Naqing Section of South Guizhou, South China contains diverse conodont evolutionary lineages among different taxa, including Idiognathoides, Idiognathodus, Diplognathodus,Neognathodus, Gondolella and Mesogondolella. There are numerous transitional forms in almost every lineage of the Naqing section, which shows that the prospects for South China to play a critical role in determining the basal Moscovian Stage definition are good.展开更多
The conodont genus Idiognathodus is one of the most important taxa in Pennsylvanian biostratigraphy.However,numerous unnamed species prevent us from understanding the evolutionary history of the genus and lower the po...The conodont genus Idiognathodus is one of the most important taxa in Pennsylvanian biostratigraphy.However,numerous unnamed species prevent us from understanding the evolutionary history of the genus and lower the potential of Idiognathodus species in the biostratigraphic correlation.New species I.anteparallelus sp.nov.,I.prosonimius sp.nov.,and I.zhuotingi sp.nov.from the Naqing section,southern Guizhou,South China are systematically described in this paper.The three new species are short-ranging taxa found in the I.podolskensis to Swadelina sp.A zones of the middle−late Moscovian.They are characterized by symmetrically paired P1 elements with a long carina,loosely space transverse ridges,and restricted accessory lobes,which are not commonly seen in the coeval I.podolskensis group.By gradually modifying adcarinal ridges,the three species constitute an evolutionary lineage.In addition,based on the new conodont data and hypotheses proposed by other researchers previously,the early evolution of the genus Idiognathodus is also discussed briefly.Species assigned to the genus Idiognathodus currently may be a polyphyletic group that evolved from different ancestors in the Bashkirian.展开更多
It is not an easy task for ammonia fuel powered ship to truly achieve engineering approach and rommerrialization,as there is still a lot of work to he clone around the research and development and application of ammon...It is not an easy task for ammonia fuel powered ship to truly achieve engineering approach and rommerrialization,as there is still a lot of work to he clone around the research and development and application of ammonia fuel power units,the innovation of containment systems,and the revision of regulations for ammonia as a marine fuel.展开更多
基金supported by the Ministry of Science and Technology of China (2006FY120300-8)the Chinese Academy of Sciences (KZCX2-YW-122, KZCX2-YW-Q050603)National Natural Science Foundation of China (NSFC), and the CAS/SAFEA International Partnership Program for Creative Research Teams
文摘Conodonts and fusulinids are the two most widely used biotic groups for subdividing and correlating Bashkirian and Moscovian strata. The definition of the base of the Global Moscovian Stage is undecided because there are many disagreements among existing boundary definition proposals,each of which has disadvantages. Declinognathodus donetzianus is easily recognized but somewhat limited in its paleogeographic distribution. Idiognathoides postsulcatus is slightly more widespread, but it is less easily identified and its occurrences may be diachronous from region to region. Diplognathodus ellesmerensis is easily recognized and even more widespread, but it is usually rare and its ancestry is not adequately known. The Naqing Section of South Guizhou, South China contains diverse conodont evolutionary lineages among different taxa, including Idiognathoides, Idiognathodus, Diplognathodus,Neognathodus, Gondolella and Mesogondolella. There are numerous transitional forms in almost every lineage of the Naqing section, which shows that the prospects for South China to play a critical role in determining the basal Moscovian Stage definition are good.
基金supported by the National Natural Science Foundation of China(grant No.42172002).
文摘The conodont genus Idiognathodus is one of the most important taxa in Pennsylvanian biostratigraphy.However,numerous unnamed species prevent us from understanding the evolutionary history of the genus and lower the potential of Idiognathodus species in the biostratigraphic correlation.New species I.anteparallelus sp.nov.,I.prosonimius sp.nov.,and I.zhuotingi sp.nov.from the Naqing section,southern Guizhou,South China are systematically described in this paper.The three new species are short-ranging taxa found in the I.podolskensis to Swadelina sp.A zones of the middle−late Moscovian.They are characterized by symmetrically paired P1 elements with a long carina,loosely space transverse ridges,and restricted accessory lobes,which are not commonly seen in the coeval I.podolskensis group.By gradually modifying adcarinal ridges,the three species constitute an evolutionary lineage.In addition,based on the new conodont data and hypotheses proposed by other researchers previously,the early evolution of the genus Idiognathodus is also discussed briefly.Species assigned to the genus Idiognathodus currently may be a polyphyletic group that evolved from different ancestors in the Bashkirian.
文摘It is not an easy task for ammonia fuel powered ship to truly achieve engineering approach and rommerrialization,as there is still a lot of work to he clone around the research and development and application of ammonia fuel power units,the innovation of containment systems,and the revision of regulations for ammonia as a marine fuel.
