INVESTIGADORES
MARENSSI Sergio Alfredo
congresos y reuniones científicas
Título:
Vertebrates from the Basal Horizons (Ypresian To Lutetian) of the Cucullaea I Allomember, La Meseta Formation, Seymour (Marambio) Island, Antarctica
Autor/es:
REGUERO, M; TAMBUSSI C,; MORS, T; BUONO, M; MARENSSI, S; SANTILLANA, S
Lugar:
Edinburgo
Reunión:
Simposio; International Symposium on Antarctic Earth Sciences; 2011
Resumen:
The La Meseta Formation
contains one of the world's most diverse assemblages of Eocene age, including terrestrial
plants, marine invertebrates and marine as well as terrestrial vertebrates. The
highly fossiliferous, lower horizons of the Cucullaea I Allomember of the La Meseta Formation
are composed of poorly consolidated, marine sandstones and siltstones which
were deposited in a coastal, deltaic and/or estuarine environment. Screen‐washing
of sediments collected from a single site, DPV 2/84 (64°1421.782S; 56°3611.685W),
has produced hundreds of bone fragments and teeth of sharks, rays, chimaeroids,
bony fishes, turtles, penguins, whales, and terrestrial mammals. The turtle
material includes two marine taxa, including one species of Dermochelyidae. The
shark fauna from this site is particularly diverse and includes species of
Hexanchus, Squalus, Centrophorus, Pristiophorus, Squatina, Striatolamia,
Odontaspis, Isurus, Carcharias, Cetorhinus, and Galeorhinus. The base of the
Cucullaea I Allomember is correlated with the late Ypresian (49.5 Ma). We
report about recent fieldwork on the site which produced a whale mandible that
may represent a primitive archaeocete. The mandible bears two triangular,
laterally compressed cheek teeth with multiple accessory denticles and wear
facets characteristic of basilosaurids, i.e. Zygorhiza or Basilosaurus, but
detailed comparisons with these taxa have yet to be made.
We will give a
description and preliminary classification of the specimen which probably
represents the earliest record of whales in Antarctica.