New elasmosaurids (Sauropterygia, Plesiosauria) from the Late Cretaceous of the Magallanes Basin, Chilean Patagonia: Evidence of a faunal turnover during the Maastrichtian along the Weddellian Biogeographic Province

Several Upper Cretaceous plesiosaur specimens recovered from southernmost Chile are described here. These were collected from upper levels of the Dorotea Formation exposed on three different localities (Sierra Baguales, Cerro Castillo, and Dumestre). The new material includes the first record of Ari...

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Autores principales:	Otero,Rodrigo A, Soto-Acuña,Sergio, Salazar S,Christian, Oyarzún,José Luis
Lenguaje:	English
Publicado:	Servicio Nacional de Geología y Minería (SERNAGEOMIN) 2015
Materias:	Austral plesiosaurs Biogeography Weddellian Province
Acceso en línea:	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-71062015000200005
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spelling	oai:scielo:S0718-710620150002000052015-06-26New elasmosaurids (Sauropterygia, Plesiosauria) from the Late Cretaceous of the Magallanes Basin, Chilean Patagonia: Evidence of a faunal turnover during the Maastrichtian along the Weddellian Biogeographic ProvinceOtero,Rodrigo ASoto-Acuña,SergioSalazar S,ChristianOyarzún,José Luis Austral plesiosaurs Biogeography Weddellian Province Several Upper Cretaceous plesiosaur specimens recovered from southernmost Chile are described here. These were collected from upper levels of the Dorotea Formation exposed on three different localities (Sierra Baguales, Cerro Castillo, and Dumestre). The new material includes the first record of Aristonectes (Plesiosauria, Elasmosauridae), previously recorded from Argentina, central Chile, and Antarctica. Additional specimens include associated postcranial skeletons as well as isolated elements. Among these, we recognize the presence of aristonectines in the three studied localities, while non-aristonectine elasmosaurids were only collected from Cerro Castillo. The specimen from Dumestre is remarkable by being a small-sized adult, indeterminate aristonectine, and could be related to known representatives from Antarctica. These new finds prove the abundance of aristonectines as well as intermediate elasmosaurids along the Magallanes Basin during the uppermost Cretaceous, while extreme long-necked elasmosaurids as well as polycotylids seems to be completely absent during this time span. This key record from southernmost Chile and its strategic placement in the middle part of the Weddellian Province gives the chance for complementing the paleobiogeography of Upper Cretaceous plesiosaurs from the Southern Hemisphere. As a first result, a faunal turnover is observed during the early Maastrichtian, when extreme (very-long necked) elasmosaurids and polycotylids disappeared from the austral record. Since the early Maastrichtian and towards the late Maastrichtian, aristonectines became differentially abundant along the southeastern Pacific and Antarctica, but moderately represented in the southwestern Atlantic. On contrary, intermediate elasmosaurids were scarce in the Antarctic-Pacific realm, but abundant in the Atlantic. The updated record of austral plesiosaurs suggest a first stage of interchange from the Northern into the Southern Hemisphere, and through the Atlantic seaway, at least since the Coniacian to the late Campanian-early Maastrichtian. During the early Maastrichtian, aristonectines were relatively frequent in the New Zealand-Antarctica archipelago, becoming abundant along southern South America during the late Maastrichtian.info:eu-repo/semantics/openAccessServicio Nacional de Geología y Minería (SERNAGEOMIN)Andean geology v.42 n.2 20152015-05-01text/htmlhttp://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-71062015000200005en10.5027/andgeoV42n1-a05
institution	Scielo Chile
collection	Scielo Chile
language	English
topic	Austral plesiosaurs Biogeography Weddellian Province
spellingShingle	Austral plesiosaurs Biogeography Weddellian Province Otero,Rodrigo A Soto-Acuña,Sergio Salazar S,Christian Oyarzún,José Luis New elasmosaurids (Sauropterygia, Plesiosauria) from the Late Cretaceous of the Magallanes Basin, Chilean Patagonia: Evidence of a faunal turnover during the Maastrichtian along the Weddellian Biogeographic Province
description	Several Upper Cretaceous plesiosaur specimens recovered from southernmost Chile are described here. These were collected from upper levels of the Dorotea Formation exposed on three different localities (Sierra Baguales, Cerro Castillo, and Dumestre). The new material includes the first record of Aristonectes (Plesiosauria, Elasmosauridae), previously recorded from Argentina, central Chile, and Antarctica. Additional specimens include associated postcranial skeletons as well as isolated elements. Among these, we recognize the presence of aristonectines in the three studied localities, while non-aristonectine elasmosaurids were only collected from Cerro Castillo. The specimen from Dumestre is remarkable by being a small-sized adult, indeterminate aristonectine, and could be related to known representatives from Antarctica. These new finds prove the abundance of aristonectines as well as intermediate elasmosaurids along the Magallanes Basin during the uppermost Cretaceous, while extreme long-necked elasmosaurids as well as polycotylids seems to be completely absent during this time span. This key record from southernmost Chile and its strategic placement in the middle part of the Weddellian Province gives the chance for complementing the paleobiogeography of Upper Cretaceous plesiosaurs from the Southern Hemisphere. As a first result, a faunal turnover is observed during the early Maastrichtian, when extreme (very-long necked) elasmosaurids and polycotylids disappeared from the austral record. Since the early Maastrichtian and towards the late Maastrichtian, aristonectines became differentially abundant along the southeastern Pacific and Antarctica, but moderately represented in the southwestern Atlantic. On contrary, intermediate elasmosaurids were scarce in the Antarctic-Pacific realm, but abundant in the Atlantic. The updated record of austral plesiosaurs suggest a first stage of interchange from the Northern into the Southern Hemisphere, and through the Atlantic seaway, at least since the Coniacian to the late Campanian-early Maastrichtian. During the early Maastrichtian, aristonectines were relatively frequent in the New Zealand-Antarctica archipelago, becoming abundant along southern South America during the late Maastrichtian.
author	Otero,Rodrigo A Soto-Acuña,Sergio Salazar S,Christian Oyarzún,José Luis
author_facet	Otero,Rodrigo A Soto-Acuña,Sergio Salazar S,Christian Oyarzún,José Luis
author_sort	Otero,Rodrigo A
title	New elasmosaurids (Sauropterygia, Plesiosauria) from the Late Cretaceous of the Magallanes Basin, Chilean Patagonia: Evidence of a faunal turnover during the Maastrichtian along the Weddellian Biogeographic Province
title_short	New elasmosaurids (Sauropterygia, Plesiosauria) from the Late Cretaceous of the Magallanes Basin, Chilean Patagonia: Evidence of a faunal turnover during the Maastrichtian along the Weddellian Biogeographic Province
title_full	New elasmosaurids (Sauropterygia, Plesiosauria) from the Late Cretaceous of the Magallanes Basin, Chilean Patagonia: Evidence of a faunal turnover during the Maastrichtian along the Weddellian Biogeographic Province
title_fullStr	New elasmosaurids (Sauropterygia, Plesiosauria) from the Late Cretaceous of the Magallanes Basin, Chilean Patagonia: Evidence of a faunal turnover during the Maastrichtian along the Weddellian Biogeographic Province
title_full_unstemmed	New elasmosaurids (Sauropterygia, Plesiosauria) from the Late Cretaceous of the Magallanes Basin, Chilean Patagonia: Evidence of a faunal turnover during the Maastrichtian along the Weddellian Biogeographic Province
title_sort	new elasmosaurids (sauropterygia, plesiosauria) from the late cretaceous of the magallanes basin, chilean patagonia: evidence of a faunal turnover during the maastrichtian along the weddellian biogeographic province
publisher	Servicio Nacional de Geología y Minería (SERNAGEOMIN)
publishDate	2015
url	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-71062015000200005
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New elasmosaurids (Sauropterygia, Plesiosauria) from the Late Cretaceous of the Magallanes Basin, Chilean Patagonia: Evidence of a faunal turnover during the Maastrichtian along the Weddellian Biogeographic Province

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