Distribution of the order Proetida (Trilobita) in Baltoscandian Ordovician strata

Pärnaste, Helje; Popp, Adrian; Owens, Robert M.

doi:10.3176/earth.2009.1.02

Cited by 12 publications

(12 citation statements)

References 46 publications

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“…These numbers are merely based on the number of new genera or subgenera that are unlikely to have originated in Baltica. Only six of these 28 newcomers represent new major groups: the cyclopygids, odontopleurids, lichids, celmids, calymenoids and telephinids (Pärnaste et al 2009). All these remained fairly unsuccessful in diversity and abundance throughout our time frame.…”

Section: Baltoscandiamentioning

confidence: 98%

Trilobites and biofacies in the Early–Middle Ordovician of Baltica and a brief comparison with the Yangtze Plate

Bergström¹,

Paernaste²,

Zhou³

2011

Estonian J. Earth Sci.

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Baltica except for Baltoscandia was subject to an early Tremadocian immigration of trilobites similar to that on other plates. In Baltoscandia the Olenid biofacies lingered on until it was replaced by the late Tremadocian Ceratopyge biofacies. For the rest of the time (Floian to mid-Darriwilian), Baltoscandia had fairly monotonous lithologies and faunas, constituting a single Asaphid biofacies with lateral variations expressed as differences largely in the relative abundance of species. In the South Urals immigration started in the earliest Tremadocian with fairly rich deep-water faunas. A poorer fauna is known from the Polar Urals. A slightly younger, sparse fauna is known from Paj-Khoj. Over most of the Ural border north of the South Urals there was a further development of first a Ceratopyge biofacies, then an eastern Asaphid biofacies, together with more siliciclastic input to the lithofacies and with fewer asaphids than in Baltoscandia. In the South Urals there was a development in the Darriwilian of a Cheirurid biofacies following the Ceratopyge biofacies. By contrast, the shelf part of the South China Plate shows a development of fifteen biofacies distinguished on the genus level, and the number of species for each biofacies is notably small. The major difference in the pattern of distribution of the biofacies probably reflects the faunal development in rather different climatic conditions, suggesting that the Yangtze block is supposedly positioned rather distant from Baltica, but still close enough to share genera inhabiting the outer shelf

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Section: Baltoscandiamentioning

confidence: 98%

Trilobites and biofacies in the Early–Middle Ordovician of Baltica and a brief comparison with the Yangtze Plate

Bergström¹,

Paernaste²,

Zhou³

2011

Estonian J. Earth Sci.

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“…In the Uuga section, northwestern Estonia, the boundary between the Joa and Mäeküla members reaches down into the P. proteus Zone (Löfgren et al 2005 , figs 2, 4). The calcareous beds of the Mäeküla Member (upper Leetse Formation) contain very rare, poorly preserved trilobites, which were recently restudied (Pärnaste 2003(Pärnaste , 2006a(Pärnaste , 2006bPärnaste et al 2009). The taxonomic association of trilobites in Estonia differs from that in Sweden (Pärnaste 2006a;Pärnaste et al 2012;Bergström et al 2013) and complicates the correlation between these regions.…”

Section: Trilobitesmentioning

confidence: 99%

On the lower boundary of the Floian Stage in Estonia

Pärnaste¹,

Viira²

2012

Estonian J. Earth Sci.

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The lower boundary of the Second Stage of the Lower Ordovician Series, the Floian Stage, is defined by the first appearance of the graptolite Tetragraptus approximatus. In the stratotype section of Diabasbrottet at Hunneberg, southern Sweden, the boundary falls within the Megistaspis planilimbata trilobite Zone and within the Oelandodus elongatus–Acodus deltatus deltatus conodont Subzone of the Paroistodus proteus Zone, and within the Hunneberg Regional Stage. Graptolites, including the index species T. approximatus, are missing in the terrigenous sediment of Estonia. The earliest trilobites are poorly preserved in this terrigenous succession. They represent an interval older than the Megalaspides dalecarlicus Zone but probably younger than the M. planilimbata Zone, and are correlative to the Prioniodus elegans conodont Zone. Thus the lower boundary of the Second Stage can be detected using mainly conodonts. In accordance with conodont occurrence, the base of the Floian (i.e. somewhat higher than the base of the O. elongatus–A. d. deltatus Subzone) falls within the Joa Member of the Leetse Formation. Probable levels have been suggested in some localities. Thus the lower part of the Leetse Formation belongs to the Tremadoc Stage, and to the Hunneberg Regional Stage

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“…8B; Cyamella sp. of Popp 2007) was found from a broadly contemporaneous geschiebe of the Baltoscandian Red Orthoceratite Limestone (Beinhorn near Hannover, Germany (Pärnaste et al 2009)). The Laurentian species has an anteriorly expanding preglabellar field similar to that of Cyamella (Fig.…”

Section: Character Changes In Different Palaeogeographical Regionsmentioning

confidence: 99%

Biometry and lifestyle of the Ordovician proetide trilobiteCyamella stensioeiOwens, 1979

Popp

Pärnaste

2011

GFF

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Biometric analyses of the trilobite Cyamella stensioei Owens, 1979, from carbonate mud mounds of the Upper Ordovician Boda Limestone of central Sweden, along with a comparison of closely allied rorringtoniid taxa from outside Baltoscandia, reveal important systematic and ecological information on this proetide taxon. Biometric analysis of the cephala of C. stensioei shows a number of instars, reflecting several ontogenetic stages, and a meraspis stage of this taxon is figured for the first time. C. stensioei is exclusively found in mass accumulations in the former, open cavities of the carbonate mud mound and was therefore most likely a cavity-dweller, possibly adapted to this lifestyle through chemosymbiosis. Some of the cavities are interpreted as former seepage conduits. Comparison of C. stensioei with other rorringtoniid trilobites suggests possible ancestors occurring in South China and Sibumasu terranes, determined earlier as Decoroproetus sp. and Cyamella sp., all differing from the genus Paracyamella, which is reassessed here. In wider terms of ancestry, they originate from Baltica or Laurentia, where the first rorringtoniids are known from the middle Darriwilian.

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Distribution of the order Proetida (Trilobita) in Baltoscandian Ordovician strata

Cited by 12 publications

References 46 publications

Trilobites and biofacies in the Early–Middle Ordovician of Baltica and a brief comparison with the Yangtze Plate

Trilobites and biofacies in the Early–Middle Ordovician of Baltica and a brief comparison with the Yangtze Plate

On the lower boundary of the Floian Stage in Estonia

Biometry and lifestyle of the Ordovician proetide trilobiteCyamella stensioeiOwens, 1979

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