INVESTIGADORES
CASADIO Silvio Alberto
congresos y reuniones científicas
Título:
Boring and encrusting organisms on species of Pycnodonte (Ostreina, Gryphaeidae) through the Cretaceous-Paleogene boundary in Patagonia, Argentina
Autor/es:
CASADIO, SILVIO; GRIFFIN, MIGUEL; PARRAS, ANA; HÅKANSSON, ECKART
Lugar:
Denver
Reunión:
Congreso; 2004 Geological Society of America Annual Meeting; 2004
Institución organizadora:
Geological Society of America
Resumen:
Changes in the boring and encrusting communities during the Cretaceous-Paleogene transition in northern Patagonia were studied on shells of three species of Pycnodonte :P. vesicularis (Lamarck) is recorded in late Maastrichtian mudstones, P. burckhardti (Böhm) is restricted to similar facies of the early Danian, and P. sarmientoi Casadío to the late Danian. All three species were free lying types inhabiting muddy bottoms on a shallow shelf. Shells of these species were important in an ecosystem largely devoid of hard substrates. Therefore, they provided a necessary and scarce resource for the associated boring and encrusting organisms. P. vesicularis shows bioerosions referable to the ichnogenera Entobia, Caulostrepsis, Maeandropolydora, Rogerella, and Feldmannia?, while encrusting organisms are represented by juvenile oysters and the bryozoans Reptocavea excavata Canu and Membranipora minuscula Canu. In addition to the juvenile oysters, shells of P. burckhardti carried Entobia, Caulostrepsis, Maeandropolydora, Rogerella, Feldmannia?, Talpina, Oichnus, and the encrusting bryozoans Membranipora trimorpha Canu, Diastopora littoralis dOrbigny, Coscinopleura planulata Canu, Reptocavea discoidea Canu, and Euritina lata Canu. P. sarmientoi has Entobia, Gatrochaenolites, Rogerella, Leptichnus, Pennatichnus, Maeandropolydora, Caulostrepsis, Talpina, Clionolithes, and fungali borings; encrusters included juvenile oysters, serpulids, balanids and the bryozoans Reptotubigera compacta Canu, Reptotubigera scalaris Canu, Ballantiostoma fibrosum Canu, Reptocavea discoidea Canu, Membraniporella capitata Canu, Proboscina striata Canu, Hippoporina planulata Canu, Haplocheilina spectabilis Canu, Porella levinseni Canu, and Exochella scalaris Canu. Results suggest that communities dependent on oysters as substrates underwent no significant changes in structure across the Cretaceous-Paleogene boundary. However, an important increase in diversity is recorded in the late Danian.