气候变化领域集成服务门户(CCPortal): Early diversification of Ordovician chitinozoans on Baltica: New data from the Jägala waterfall section; northern Estonia

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DOI	10.1016/j.palaeo.2019.04.002
	Early diversification of Ordovician chitinozoans on Baltica: New data from the Jägala waterfall section; northern Estonia
	Nõlvak J.; Liang Y.; Hints O.
发表日期	2019
ISSN	0031-0182
起始页码	14
结束页码	24
卷号	525
英文摘要	Chitinozoans are a group of biostratigraphically valuable microfossils which appeared in the Tremadocian and diversified during the rest of the Great Ordovician Biodiversification Event, to become extinct in the Devonian. The early diversification of chitinozoans on the Baltica palaeocontinent has remained poorly known due to preservation and collecting bias. In this study we document the distribution of chitinozoans through the upper Tremadocian to lower Darriwilian strata in the Jägala waterfall section from northern Estonia, in order to better understand the regional diversity patterns and biogeographic links. Fifty samples were studied from the 7.5 m succession of sandstones, marls and carbonates revealing 47 chitinozoan species and 11 genera. The lowermost productive samples, attributed to the late Tremadocian, represent the earliest rich chitinozoan fauna from Baltica. Combined with previous reports this shows a diversity peak in the Tremadocian with balanced total diversity reaching 17, possibly followed by a decline in the Floian and then a rather gradual increase through the Dapingian and early Darriwilian. The new diversity curve shows more than three times higher values for the Tremadocian and Dapingian than indicated in previous studies, and thus less abrupt radiation in the Darriwilian. The Jägala section provided also new data on the regional biozonal species Conochitina cucumis and Cyathochitina regnelli, which characterize the middle and upper Volkhov and lower Kunda regional stages, respectively. Several other biostratigraphically significant taxa typical of other regions were recovered from the Jägala section, including Conochitina decipiens and Desmochitina bulla. A new short-ranging species Laufeldochitina toilaensis sp. nov. is introduced, having potential to become an index species for middle Dapingian strata. The early Darriwilian assemblage from Jägala includes Rhabdochitina sp. A with up to 2.7 mm long vesicle, making it the largest chitinozoan ever reported. © 2019 Elsevier B.V.
英文关键词	Baltoscandia; Biodiversity; Dapingian; Darriwilian; GOBE; Tremadocian
语种	英语
scopus关键词	adaptive radiation; Baltica; fauna; fossil record; invertebrate; new species; preservation; species diversity; Tremadocian; waterfall; zoogeography; Estonia; Kunda; Chitinozoa; Conochitina; Cucumis; Cyathochitina; Desmochitina; Rhabdochitina
来源期刊	Palaeogeography, Palaeoclimatology, Palaeoecology
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/150963
作者单位	Department of Geology, Tallinn University of Technology, Ehitajate tee 5, Tallinn, 19086, Estonia; CAS Key Laboratory of Economic Stratigraphy and Palaeogeography, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, 39 East Beijing Road, Nanjing, 210008, China
推荐引用方式 GB/T 7714	Nõlvak J.,Liang Y.,Hints O.. Early diversification of Ordovician chitinozoans on Baltica: New data from the Jägala waterfall section; northern Estonia[J],2019,525.
APA	Nõlvak J.,Liang Y.,&Hints O..(2019).Early diversification of Ordovician chitinozoans on Baltica: New data from the Jägala waterfall section; northern Estonia.Palaeogeography, Palaeoclimatology, Palaeoecology,525.
MLA	Nõlvak J.,et al."Early diversification of Ordovician chitinozoans on Baltica: New data from the Jägala waterfall section; northern Estonia".Palaeogeography, Palaeoclimatology, Palaeoecology 525(2019).