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Article: The early Ludfordian leintwardinensis graptolite Event and the Gorstian–Ludfordian boundary in Bohemia (Silurian, Czech Republic)

Publication: Palaeontology
Volume: 57
Part: 5
Publication Date: September 2014
Page(s): 1003 1043
Author(s): <p>Petr Štorch, Štěpán Manda and David K. Loydell</p>
Addition Information

How to Cite

ŠTORCH, P., MANDA, Š. and LOYDELL, D.K. 2014. The early Ludfordian leintwardinensis graptolite Event and the Gorstian–Ludfordian boundary in Bohemia (Silurian, Czech Republic). Palaeontology57, 5, 1003–1043. doi: 10.1111/pala.12099

Author Information

  • Petr Štorch - Department of Palaeobiology and Palaeoecology, Institute of Geology AS CR, Praha 6, Czech Republic (email: storch@gli.cas.cz)
  • Štěpán Manda - Division of Regional Geology of Sedimentary Formations, Czech Geological Survey, Praha 1, Czech Republic (email: stepan.manda@geology.cz)
  • David K. Loydell - School of Earth and Environmental Sciences, University of Portsmouth, Portsmouth, UK (email: david.loydell@port.ac.uk)

Publication History

  • Issue published online: 12 SEP 2014
  • Article first published online: 24 FEB 2014
  • Manuscript Accepted: 27 DEC 2013
  • Manuscript Received: 24 JUL 2013

Funded By

Czech Science Foundation. Grant Number: 205/09/0703

Online Version Hosted By

Wiley Online Library
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Abstract

The late Gorstian to early Ludfordian hemipelagic succession of the south-eastern part of the Prague Synform preserves a rich fossil record dominated by 28 species of planktic graptoloids associated with pelagic myodocopid ostracods, pelagic and nektobenthic orthocerid cephalopods, epibyssate bivalves, nektonic phyllocarids, rare dendroid graptolites, brachiopods, crinoids, trilobites, sponges and macroalgae. Faunal dynamics have been studied with particular reference to graptolites. The early Ludfordian leintwardinensis graptolite extinction Event manifests itself as a stepwise turnover of a moderate diversity graptolite fauna rather than an abrupt destruction of a flourishing biota. The simultaneous extinction of the spinose saetograptids Saetograptus clavulus, Saetograptus leintwardinensis and the rare S. sp. B. at the top of the S. leintwardinensis Zone was preceded by a short-term acme of S. clavulus. Cucullograptus cf. aversus and C. rostratus vanished from the fossil record in the lower part of the Bohemograptus tenuis Biozone. No mass proliferation of Bohemograptus has been observed in the postextinction interval. Limited indigenous speciation gave rise to Pseudomonoclimacis kosoviensis and Pseudomonoclimacis cf. dalejensis. Egregiograptus (the only novel element of cryptic origin) made its earliest occurrence in association with the latest cucullograptids. A postextinction graptolite assemblage of moderate diversity, composed for the most part of long-ranging taxa, persisted through the middle and upper tenuis Biozone until new rediversification in the Neocucullograptus inexpectatus Biozone. Unlike the graptoloids, the planktic, epiplanktic, nektonic and nektobenthic shelly fauna did not suffer significant extinction in the early Ludfordian. The Gorstian–Ludfordian boundary is placed at the lowest occurrence of S. leintwardinensis in spite of the very modest graptolite record available from the Ludfordian GSSP where no graptolites occur below the basal bed of the Lower Leintwardine Formation. Elsewhere, the Gorstian–Ludfordian boundary has been placed at the base of the Saetograptus linearis Biozone which has been considered roughly correlative with the leintwardinensis Biozone. Indeed, our morphometric study places the worldwide biozonal index species S. linearis in synonymy with S. leintwardinensis and thus considerably enhances the biostratigraphical utility of the latter index species. Pseudomonoclimacis antiqua sp. nov. is described.

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