Search results for "Cambrian Series 3"
showing 5 items of 5 documents
Unravelling extrinsic and intrinsic factors of the early Palaeozoic diversification of blastozoan echinoderms
2010
19 pages; International audience; The Subphylum Blastozoa represents more than one third of the early Palaeozoic echinoderm fauna. A comprehensive database including all records of blastozoans was built to provide quantitative analyses of palaeogeography and diversity patterns and processes, for the 10 classes currently included in this subphylum during the early Palaeozoic. The global pattern of taxonomic diversity shows two peaks during the Cambrian Series 3 and the Late Ordovician intervals. In Cambrian times, the high taxonomic diversity seems to be related with a high turnover rate and a high endemicity of blastozoan genera, whereas in Ordovician times, the rise in diversity is associa…
Proposal of a reference section and point for the Cambrian Series 2-3 boundary in the Mediterranean subprovince in Murero (NE Spain) and its intercon…
2011
The classical lower-middle Cambrian boundary is approximately equivalent with the boundary of the Cambrian Series 2 and 3, which is now in the process of definition by the International Subcommission on Cambrian Stratigraphy. Currently, there are two oryctocephalid trilobite species first appearance data (FAD) that are suggested as possible markers of this level: Ovatoryctocara granulata Tchernysheva, 1962 and Oryctocephalus indicus (Reed, 1910), respectively. Until now neither of these two species has been recorded in the Mediterranean subprovince or Baltica. As a result, in these regions a level potentially correlating with either the FAD of Ovatoryctocara granulata or Oryctocephalus indi…
The first record ofDinesus(Trilobita, Dinesidae) in the Cambrian of the Mediterranean region
2011
An important problem facing inter-regional correlation in the Cambrian is the scarcity of shared taxa between different palaeogeographic domains. Currently, species of the Corynexochida are proposed as tools to define the base of Cambrian Series 3. However, few Mediterranean Corynexochida species are known. A specimen of Dinesus truyolsi comb. nov. from the middle Cambrian of Spain represents the first record of this genus in the Acadobaltic province. Erbia and Tingyuania are accepted as junior subjective synonyms of Dinesus, and we now recognize 22 species within this genus. Dinesus has been found previously in lower to middle Cambrian strata of Australia, Russia, Kazakhstan, North America…
A blind trilobite with Baltic affinities from Cambrian Series 3 of the Iberian Chains, Spain, and its stratigraphical and palaeobiogeographical signi…
2015
Three cranidia of a conocoryphid trilobite are described from the lower Caesaraugustan Regional Stage (upper part of provisional Cambrian Stage 5 within Cambrian Series 3) in the Iberian Chains, Spain. The material is from the upper part of the Mansilla Formation and the base of the overlying Murero Formation. It closely resembles Bailiella tenuicincta (Linnarsson, 1879), which has previously been described from the Ptychagnostus gibbus (Cambrian Stage 5) and lower P. atavus zones (lower Drumian Stage) of Baltica (Sweden and Bornholm), and from the P. atavus Zone of West Avalonia (Newfoundland). The record of B. cf. tenuicincta from the Mediterranean margin of West Gondwana provides additio…
Bailiaspis (Trilobita) with English affinities from the Mansilla Formation (Cambrian Series 3 of the Iberian Chains; NE Spain)
2020
A new study of the trilobite record in the Mansilla Formation (Iberian Chains, NE Spain) has led to the discovery of the presence of Bailiaspis aff. tuberculata, B. cf. tuberculata and Bailiaspis sp., the first certain citation of this genus in the Mediterranean subprovince. The age of the findings extends from Eccaparadoxides asturianus Zone (upper Leonian) to the lowermost Badulesia tenera Zone (lower Caesaraugustan), which correspond to the upper part of Stage 5 of Cambrian Series 3 and, probably, the lowermost Drumian. The specimens show the cranidial anterior border expanding backwards, forming a plectrum that is characteristic of Bailiaspis. The main characters of the three taxa inclu…