In recent years,the taxonomy and systematics of the cartilaginous fish taxa from the Eocene La Meseta Formation of Seymour(Marambio)Island,Antarctica have been extensively discussed in a series of papers,resulting in ...In recent years,the taxonomy and systematics of the cartilaginous fish taxa from the Eocene La Meseta Formation of Seymour(Marambio)Island,Antarctica have been extensively discussed in a series of papers,resulting in a complete revision of the Antarctic Eocene ichthyofauna housed in the Vertebrate Paleontology collection of the Museo de La Plata,Argentina.This collection constitutes one of the largest and taxonomically most diverse in the world,with approximately 20000 specimens,which provides a solid database used for the analysis of qualitative and quantitative chondrichthyan taxonomic composition.The information provided herein might be useful to understand the sudden decline in chondrichthyan taxonomic diversity towards the top of La Meseta Formation as well as its potential relationship with environmental changes during the Eocene.展开更多
Antarctica has significant environmental,scientific,historic,and intrinsic values,all of which are worth protecting into the future.This continent has a discrete number of places of scientific interest that exhibit gr...Antarctica has significant environmental,scientific,historic,and intrinsic values,all of which are worth protecting into the future.This continent has a discrete number of places of scientific interest that exhibit great potential as natural heritage sites;its geodiversity is of fundamental importance to scientific values of the continent,and the pursuit of geological and paleontological knowledge has had a strong influence on its historical values.Seymour Island was once called the‘Rosetta Stone’of Southern Hemisphere paleobiology,because this small island provides the most complete and richly fossiliferous Late Cretaceous–Paleogene sequence in Antarctica.In particular,fossil vertebrates form part of the evidence used in reconstructing the history of life on Antarctica.Paleontological heritage is considered a subset of geo-heritage that embodies both natural and historical components which has received only indirect recognition.Seymour Island is an outstanding paleontological area with high heritage value of its Late Cretaceous/Paleogene vertebrates and should be considered for geo-conservation and protection.This paper reviews vertebrate fossil occurrences and outcrops on Seymour Island and discusses some threats to these fossil sites.展开更多
The Eocene–Oligocene Southern Ocean is thought to have played a major role in cetacean evolution.Yet,fossils from its heart—Antarctica—are rare,and come almost exclusively from the Eocene La Meseta and Submeseta fo...The Eocene–Oligocene Southern Ocean is thought to have played a major role in cetacean evolution.Yet,fossils from its heart—Antarctica—are rare,and come almost exclusively from the Eocene La Meseta and Submeseta formations of Marambio(Seymour)Island.Here,we provide a summary and update of this crucial fossil assemblage,and discuss its relevance in the broader context of cetacean evolution.To date,Eocene specimens from Antarctica include basilosaurids,a group of archaic stem cetaceans that had already fully adapted to life in water;and the archaic toothed mysticete Llanocetus,the second oldest crown cetacean on record(ca.34 Ma).This Eocene co-occurrence of stem and crown cetaceans is highly unusual,and otherwise only observed in Peru.Though related,at least some of the Antarctic species appear to be different from,and notably larger than their Peruvian counterparts,suggesting an early differentiation of the high latitude cetacean fauna.展开更多
基金Thanks to the Agencia Nacional de Promoción Científica y Tecnológica for financial support trough PICT 2017-0607(to MR),PICT 2019-02419(to SGC).
文摘In recent years,the taxonomy and systematics of the cartilaginous fish taxa from the Eocene La Meseta Formation of Seymour(Marambio)Island,Antarctica have been extensively discussed in a series of papers,resulting in a complete revision of the Antarctic Eocene ichthyofauna housed in the Vertebrate Paleontology collection of the Museo de La Plata,Argentina.This collection constitutes one of the largest and taxonomically most diverse in the world,with approximately 20000 specimens,which provides a solid database used for the analysis of qualitative and quantitative chondrichthyan taxonomic composition.The information provided herein might be useful to understand the sudden decline in chondrichthyan taxonomic diversity towards the top of La Meseta Formation as well as its potential relationship with environmental changes during the Eocene.
基金Funding for this study was provided by PICT 0607-2018 and UNLP 11N812
文摘Antarctica has significant environmental,scientific,historic,and intrinsic values,all of which are worth protecting into the future.This continent has a discrete number of places of scientific interest that exhibit great potential as natural heritage sites;its geodiversity is of fundamental importance to scientific values of the continent,and the pursuit of geological and paleontological knowledge has had a strong influence on its historical values.Seymour Island was once called the‘Rosetta Stone’of Southern Hemisphere paleobiology,because this small island provides the most complete and richly fossiliferous Late Cretaceous–Paleogene sequence in Antarctica.In particular,fossil vertebrates form part of the evidence used in reconstructing the history of life on Antarctica.Paleontological heritage is considered a subset of geo-heritage that embodies both natural and historical components which has received only indirect recognition.Seymour Island is an outstanding paleontological area with high heritage value of its Late Cretaceous/Paleogene vertebrates and should be considered for geo-conservation and protection.This paper reviews vertebrate fossil occurrences and outcrops on Seymour Island and discusses some threats to these fossil sites.
文摘The Eocene–Oligocene Southern Ocean is thought to have played a major role in cetacean evolution.Yet,fossils from its heart—Antarctica—are rare,and come almost exclusively from the Eocene La Meseta and Submeseta formations of Marambio(Seymour)Island.Here,we provide a summary and update of this crucial fossil assemblage,and discuss its relevance in the broader context of cetacean evolution.To date,Eocene specimens from Antarctica include basilosaurids,a group of archaic stem cetaceans that had already fully adapted to life in water;and the archaic toothed mysticete Llanocetus,the second oldest crown cetacean on record(ca.34 Ma).This Eocene co-occurrence of stem and crown cetaceans is highly unusual,and otherwise only observed in Peru.Though related,at least some of the Antarctic species appear to be different from,and notably larger than their Peruvian counterparts,suggesting an early differentiation of the high latitude cetacean fauna.
