Protovirgularia dichotoma—Protovirgularia rugosa: An Example of a Compound Trace Fossil from the Lower Cretaceous (Agrio Formation) of the Neuquén Basin, Argentina
Аннотация:This study focuses on the description of a compound trace fossil from the Cretaceous of the Neuquén Basin, Argentina. This structure comprises two discrete ichnotaxa: Protovirgularia cf. dichotoma M'Coy, 1850, and Protovirgularia cf. rugosa (Miller and Dyer, 1878 Miller, S. A. and Dyer, C. B. 1878. Contributions to paleontology. Journal of the Cincinnati Society of Natural History, 1: 24–39. [Google Scholar]). Open nomenclature is chosen due to some differences from the ichnospecies diagnoses. The compound trace as a whole is the product of locomotion and resting behaviors (repichnia and cubichnia); this is not questioned but discussed. The inferred producer is a deposit-feeding palaeotaxodont bivalve, which belongs to a taxonomic group almost unknown and not yet reported in the Neuquén Basin. The sample was taken from rocks interpreted as being deposited in a tide-influenced, marginal-marine setting, corresponding to the uppermost section of the Agrio Formation. This also represents one of the first cases of a compound trace fossil described for the Neuquén Basin.
