INVESTIGADORES
CICHOWOLSKI Marcela
congresos y reuniones científicas
Título:
Early Cretaceous encrusting faunas from the Neuquén Basin, west-central Argentina, and their paleoecological implications
Autor/es:
LUCI, L., LAZO, D.G., CICHOWOLSKI, M.
Lugar:
Ankara
Reunión:
Simposio; 9th INternational Symposium on the Cretaceous System; 2013
Resumen:
The Agrio Formation (late Valanginian ? earliest
Barremian) of the Neuquén Basin (Argentina) presents diverse marine mollusk
assemblages. Hard substrate faunas, however, have been given little attention. Shells
of three cephalopods and two bivalve basibiont genera were examined for
encrusters, in order to characterize and describe them. Nineteen encrusting
taxa were found. Encrusting bivalves were represented by a gryphaeid oyster and
a plicatuliid, while byssate one comprised mytilids and anomiids. Six serpulids
and one sabellid polychaete worms were recognized. Bryozoans comprised five
cyclostomes, and one cheilostome. Agglutinated foraminifers are represented by
one species, and a single coral specimen was also found. Oysters are
overwhelmingly dominant, usually exceeding 70% of the fauna. Serpulids are a
distant second in abundance, mostly represented by a single species. Cyclostome
bryozoans are third in importance. The encrusting assemblage is indicative of a
well-oxygenated, shallow-marine setting of moderate to high energy, and
moderate to low turbidity. Several of the taxa show Tethyan affinities. While in
composition this fauna is in agreement with other Early Cretaceous hard-substrate
faunas, unlike most other cases solitary organisms are strongly predominant, in
both diversity and abundance, over colonial species, resulting in a
characteristic encrusting fauna strongly dominated by aggregated oysters and
serpulids.