NUEVO REGISTRO DE TRES ESPECIES DE Orthaulax (Gastropoda: Strombidae) EN LAS FORMACIONES SAN LUIS Y PATIECITOS DEL OLIGOCENO TARDÍO – MIOCENO TEMPRANO EN EL ESTADO FALCÓN, VENEZUELA
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Universidad Industrial de Santander
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Hasta ahora, el género Orthaulax ha sido considerado ausente en las cuencas oligo-miocenas de Sudamérica. Proliferó en los ambientes infralitorales de las plataformas calcáreas de las Antillas Mayores y Menores, cuyo desarrollo estuvo influenciado por el predominio de aguas cálidas ricas en plancton y oxígeno, que penetraban desde el Océano Pacífico. Sin embargo, en las cuencas Venezolanas caracterizadas por presentar sedimentos lodosos, aguas marinas zonificadas y escasez de carbonatos, fueron encontrados 6 ejemplares fósiles, correspondientes a Orthaulax aguadillensis, O. conoides y O. inornatus de la Familia Strombidae en todas las etapas de crecimiento y con una alta calidad de preservación, en yacimientos del municipio Bolívar, donde afloran la formación arrecifal (San Luis) y de ensenada marina somera (Patiecitos). De manera complementaria, se reporta la presencia de larvas de balánidos que confirman el predominio de paleoprofundidades no menores a 16 m. Por último, este nuevo registro del género Orthaulax ofrece información sobre el paleoambiente imperante durante el origen y extinción del complejo arrecifal de San Luis e incrementa a cuatro el número de especies de megagasterópodos presentes en las formaciones Paleogeno - Neogeno marino terciarias del Estado Falcón.
Until now, the genus Orthaulax has been considered as absent from the Oligo-Miocene basins of South America. On the other hand, it proliferated in the infralittoral environments from the calcareous platforms of the Greater and Lesser Antilles, whose development was influenced by the predominance of plankton-rich and oxygen-rich warm waters entering from the Pacific Ocean. However, in the Venezuelan basins, characterized by muddy sediments, zoned marine waters and the lack of carbonates; six fossil specimens were found and assigned to Orthaulax aguadillensis, O. conoides and O. inornatus, belonging to the family Strombidae, also representing all growth stages and with high quality preservation in paleontological sites from the Bolívar Municipality; where reefal (San Luis) and shallow marine inlet (Patiecitos) formations outcrop. To complement this, we also report the presence of barnacle larvae, which confirms the prevalence of paleodepths of no less than 16 m. Finally, this new record of the genus Orthaulax, provides information on the prevailing paleoenvironment during the rise and extinction of the San Luis reefal complex and increases to four the number of gastropods present in Paleoegene-Neogene marine formations of the Falcón State.
Until now, the genus Orthaulax has been considered as absent from the Oligo-Miocene basins of South America. On the other hand, it proliferated in the infralittoral environments from the calcareous platforms of the Greater and Lesser Antilles, whose development was influenced by the predominance of plankton-rich and oxygen-rich warm waters entering from the Pacific Ocean. However, in the Venezuelan basins, characterized by muddy sediments, zoned marine waters and the lack of carbonates; six fossil specimens were found and assigned to Orthaulax aguadillensis, O. conoides and O. inornatus, belonging to the family Strombidae, also representing all growth stages and with high quality preservation in paleontological sites from the Bolívar Municipality; where reefal (San Luis) and shallow marine inlet (Patiecitos) formations outcrop. To complement this, we also report the presence of barnacle larvae, which confirms the prevalence of paleodepths of no less than 16 m. Finally, this new record of the genus Orthaulax, provides information on the prevailing paleoenvironment during the rise and extinction of the San Luis reefal complex and increases to four the number of gastropods present in Paleoegene-Neogene marine formations of the Falcón State.
Keywords
Orthaulax, Oligocene-Miocene, Falcón, Venezuela, Nuevo registro, género Orthaulax, Venezuela, Oligoceno-Mioceno