Ostrácodos (Crustacea, Ostracoda) y carófitos (Chlorophyta, Charales) de la Formación Desencuentro (Mioceno superior), provincia de La Rioja, Argentina
Abstract
Resumen. Se describen e ilustran los ostrácodos y carófitos de la Formación Desencuentro, provincia de La Rioja, Argentina. La asociación muestra baja diversidad con seis taxones de ostrácodos: Eucypris sp., Darwinula sp., Cyamocytheridea sp., Cyprideissalebrosahartmanni Ramírez, Limnocythere aff. L. reticulata Sharpe, Limnocythere sp., y dos especies de carófitos: Charazeylanica s. l. Klein exWilldenow y Charamusacchioi García sp. nov. El hallazgo de veinte girogonites bien preservados de Charamusacchioi permitió evaluar su variabilidad morfológica, establecer su relación con la especie actual CharahornemanniiWallman, y arribar a la conclusión de que se trata de una nueva especie. Estos taxones indican un ambiente acuático de aguas tranquilas oligohalinas a mesohalinas, con posible aporte de agua dulce, en un área tropical a subtropical, con temperatura media de alrededor de 15-20ºC. Abstract. OSTRACODS (CRUSTACEA, OSTRACODA) AND CHAROPHYTES (CHLOROPHYTA, CHARALES) FROM THE DESENCUENTRO FORMATION (UPPER MIOCENE), LA RIOJA PROVINCE, ARGENTINA. Ostracods and charophytes from the Desencuentro Formation (La Rioja Province, Argentina) are described and illustrated. The association has low diversity with six ostracod taxa: Eucypris sp., Darwinula sp., Cyamocytheridea sp., Cyprideis salebrosahartmanni Ramírez, Limnocythere aff. L. reticulata Sharpe, Limnocythere sp. and two charophytes: Charazeylanica s. l. Klein exWilldenow and Charamusacchioi García sp. nov. The availability of twenty well preserved gyrogonites of Charamusacchioi sp. nov. allowed to observe the intra-populational morphological variability, to relate the new species with the extant Charahornemannii Wallman, and to conclude that it is a new species. The assemblage indicates a calm aquatic environment with oligohaline to mesohaline water, with a possible input of fresher water, in a tropical to subtropical area, with mean temperature of about 15-20ºC.Downloads
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