The extinct nautiloid Aturia in the Middle Miocene of Pacific South America: new data from the Pisco Lagerstätte of Peru

We report on an aturiid (Cephalopoda: Nautiloidea) shell from the Pisco Formation, a Neogene marine sedimentary unit of the East Pisco Basin (southern Peru) that is widely known for its rich and exquisitely preserved marine vertebrate fossil content, including an outstanding cetacean assemblage. The studied specimen was collected from Middle Miocene strata exposed in the vicinity of Cerro Submarino. It consists of an internal mould of a phragmocone and is tentatively identified herein as belonging to the widespread, long- ranging species Aturia cubaensis. This fossil represents the first occurrence of Aturia in the Middle Miocene of the Pacific margin of South America; as such, it fills a gap in the chronostratigraphic distribution of the Southeastern Pacific finds of this genus, helping to bridge the Lower and Upper Miocene segments of its regional fossil record. The rarity of Aturia in the shelfal Cenozoic deposits of the East Pisco Basin may reflect the palaeoenvironmental habits of this extinct cephalopod genus, which may have lived in the upper bathyal zone, at about 250-350 m water depth. Despite recent suggestions that some extinct and extant marine mammal ecomorphotypes (including some odontocetes) were likely predators of nautiloids, there is no indication that any member of the diverse and abundant toothed whale faunas of the Pisco Formation exploited these shelled cephalopods as a relevant food source.