Fossil Penaeidae (Crustacea: Decapoda) from the Loyola Formation, Ecuador

Resumen

Specimens of fossil shrimp, preserved in the fine clastic sediments of the middle Miocene Loyola Formation, within the Cuenca Basin, Ecuador, have been identified as IPenaeus maddeni n. sp. Their presence strongly suggests that marine conditions existed within the basin during the deposition of some of the Loyola Formation and that the geological history of marine influence in Andean intermontane basins is complex. This observation is reinforced by the presence of claws of a crab identified as INecronectes proavitus (Rathbun) from a nearby locality within the formation. Because the identification of the crab claws is questionable, their use as a stratigraphic index is more limited than previously suggested.