Bioerosion structures in Crepidula (Mollusca, Gastropoda) as indicators of latitudinal palaeoenvironmental changes: Example from the marine Quaternary of Argentina

摘要: Abstract Late Quaternary marine skeletal concentrations from Argentina are rich in molluscs exhibiting a great variety of bioerosion structures. The shells Crepidula , characteristic gastropod occurring along more than 2000 km coastline between the Rio de La Plata margin and southern Patagonia, show traces dwelling, predation anchoring activities made by porifers, bryozoans, annelids, other gastropods brachiopods. Caulostrepsis, Entobia, Maeandropolydora, Iramena, Oichnus, Finichnus, Pennatichnus, Pinaceocladichnus, Podichnus Renichnus occur on outer shell surface. Finichnus Oichnus only present entire area full time span considered. most structures produced polychaetes predatory gastropods. Traces annelids preferentially central sector, where predators gained access to soft parts prey. By contrast, encrusting or branching bryozoan colonies widely distributed as they can attach any sector regardless features available. No strict correlation is evident ichnodiversity either latitude, but linked local oceanographical/biotic controls. For with majority ichnotaxa general trend higher degree at latitudes controlled sea surface temperature/productivity: for modern Holocene, several peaks match well-constrained conditions (substrate, salinity, thermal fronts). this does not hold Pleistocene: dissimilar probably prevailed, especially during Last Interglacial (colder waters richer nutrients).