CONICET | Buscador de Institutos y Recursos Humanos

The coral patch reef of the La Manga Formation at Bardas Blancas (Mendoza Province) is a good example of this kind of structurefor the Upper Jurassic (Oxfordian) of the Neuquén Basin. In previous reports, four different genera of corals were identified: Actinastrea, Australoseris,Garateastrea, and Thamnasteria. A new systematic revision of the previously studied specimens and new material, lead to the rejectionof the assignments to Garateastrea, Actinastrea, and Thamnasteria, which are now identified as Australoseris, Stelidioseris, and Etallonasteria,respectively, while those originally identified as Australoseris are maintained. New results are based on a taphonomic analysis carried out torecognize the bias introduced in the systematic assignments by different preservational?taphonomic?grades. Four taphonomic grades weredefined as Tg0?Tg3, with an increasing degree of taphonomic distortion. Tg0 is an ideal state with preservation of the microstructure. Theloss of microstructural features occurs in Tg1?Tg3, preventing assignment at the suprageneric to the specific level. Additionally, those specimenswith Tg2 and Tg3 suffered a change in their macrostructural features giving rise to apparent morphological details that may lead towrong assignments. Tg3 is the stage of preservation most frequently seen in the field. This is not useful for systematic studies due to theloss of all diagnostic features. Samples with Tg1 are useful for systematic studies because most of the macrostructural characters are preservedalmost in their original condition. Taphonomic analyses of the specimens are necessary to carry out reliable systematic studies for latermeasurements of richness and evenness.