Amphibian taphonomy and its application to the fossil record of Dolina (middle Pleistocene, Atapuerca, Spain)

The middle Pleistocene site of Atapuerca (Spain) has many archaeological, palaeontological and human remains in stratigraphic position. Amphibian remains are abundant and easily identifiable in many levels of the site. We have investigated the taphonomy of the amphibian remains, with the question to be answered being their source. Did the amphibians live and die inside the cave, as occurs naturally nowadays, or were their remains brought into the cave by predator activity or by other agents such as sedimentary motion, water transport, etc. There is no reference source of taphonomic alterations on amphibian remains and we provide some basic background for this, using two approaches. One consisted of analyzing a collection of scats and pellets of known predators, and based on the alterations and breakage present in the bones digested by each, we produce a set of categories that will be an analytical tool to be applied to the fossil record. Secondly, we have carried out several laboratory experiments to measure the effects of weathering and water transport on amphibian remains. We subsequently analyzed the fossil amphibian remains from the middle Pleistocene site of Dolina (Atapuerca, Spain). The results showed that the taphonomic processes observed in the Atapuerca sequence of TD4–TD5 are the same, and the amphibian remains at these levels entered the cave deposits in the scats of a mammalian predator. This has been identified as a mustelid, which is an opportunistic predator which would feed on amphibians from the surrounding environment.