Revision of Valanginian Steinmanellinae bivalves from the Neuquén basin, West-central Argentina, and their biostratigraphic implications
We present a new species of Steinmanella Crickmay from the Valanginian of the Neuquén Basin, west-central Argentina, and at the same time update a Valanginian-earliest Barremian bivalve zonation which is integrated into the local, Chilean and European standard ammonoid zonations. Steinmanella caicay...
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| Autores principales: | , |
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2013
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_01956671_v45_n_p60_Lazo http://hdl.handle.net/20.500.12110/paper_01956671_v45_n_p60_Lazo |
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| Sumario: | We present a new species of Steinmanella Crickmay from the Valanginian of the Neuquén Basin, west-central Argentina, and at the same time update a Valanginian-earliest Barremian bivalve zonation which is integrated into the local, Chilean and European standard ammonoid zonations. Steinmanella caicayensis sp. nov. presents a moderately inflated shell, a subtriangular outline, well-developed carinaeand a straight to moderately convex anterior margin. Steinmanella is very abundant in the Tithonian-Barremian interval in the basin and thus provides an ideal opportunity to perform detailed taxonomic and stratigraphic studies; a former zonation based on these trigonioids is here revised and expanded with a thorough revision of Valanginian occurrences based on new material. Two new zones are proposed, namely the S.quintucoensis and S.caicayensis zones, encompassing Valanginian times. The proposed bivalve zonation encompassing the Valanginian-earliest Barremian time interval can be useful in correlating with other southwestern Gondwanan regions, such as Perú, Chile, South Africa, Tanzania, and India, where Steinmanella has been recorded. © 2013 Elsevier Ltd. |
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