Protovirgularia dichotoma?Protovirgularia rugosa: An Example of a Compound Trace Fossil from the Lower Cretaceous (Agrio Formation) of the Neuquén Basin, Argentina

FERNÁNDEZ, DIANA E.; PAZOS, PABLO J.; AGUIRRE-URRETA, M. BEATRIZ

ICHNOS-AN INTERNATIONAL JOURNAL FOR PLANT AND ANIMAL TRACES

TAYLOR & FRANCIS INC

Año: 2010 vol. 17 p. 40 - 47

1042-0940

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). 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, marginalmarine 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.