Meléndez Hevia, GuillermoBello Villalba, J.Ferrández, Y.Fidalgo, A.2015-04-082015-04-081997http://hdl.handle.net/10272/10276The ammonite species Perisphincjtes (bichotómosphinctes) wartac BUKOWSKI is precisely localised at the top of the middle Oxfordian Transversarium Biózohe (Rotoides Subbiozone) allowing the recognition of a well-defined biostratigraphic unii, i.e. the Wartae Biohorizon. Per. wartae is usually recognized as the transitional form between the subgenera P. (Dichotomosphinctes) and P. (Dichotomo'ceras) BÜCKMÁÑ. Representatives of P. wartae show clearly intermediate features between both taxa, this évoluiiohary change allowing a precise characterisation of the biostratigraphic boundary between the middle Oxfordian Transversarium and Bifurcatus zones. In eastern Iberia, àcross the Iberian and Catalan Basins, the boundary between both biozones is marked by a sharp stratigràphic discontinuity partly affecting the development of the Wartae Horizon. Yet this biostratigraphic interval has been widely recognised throughout the studied area by the common occurrence of thè species Rwartae, which has allowed thè precise palaeontological (biórhètrical) and evoluiioriáry characterisation of this speciesspaAtribución-NoComercial-SinDerivadas 3.0 Españahttp://creativecommons.org/licenses/by-nc-nd/3.0/es/PalaeontologyBiostraiigraphyAmmonitesMiddle OxfordianEvolutionRotoides SubbiozoneWartae Biohorizonjournal articleopen access