Ascocerid cephalopods from the Hirnantian?-Llandovery stages of the southern Paraná Basin (Paraguay, South America): First record from high paleolatitudes

Mostrar todas las versiones(2)

Ascocerid cephalopods are described for the first time from high paleolatitudes of Gondwana. Studied material was collected from the Hirnantian?-Llandovery strata of the Eusebio Ayala and Vargas Pena formations, Parana Basin, southeastern Paraguay. The specimens are poorly preserved and were questio...

Descripción completa

Detalles Bibliográficos
Autores principales: Cichowolski, Marcela, Uriz, Norberto Javier, Alfaro, Marta Beatríz, Galeano Inchausti, J.C.
Formato: Articulo
Lenguaje:Inglés
Publicado: 2018
Materias:
Geología
Structural basin
Juvenile
Geology
Stage (stratigraphy)
Paleontology
Gondwana
Conch
Nekton
Demersal zone
Marine transgression
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/125863
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-125863
record_format dspace
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Geología
Structural basin
Juvenile
Geology
Stage (stratigraphy)
Paleontology
Gondwana
Conch
Nekton
Demersal zone
Marine transgression
spellingShingle Geología
Structural basin
Juvenile
Geology
Stage (stratigraphy)
Paleontology
Gondwana
Conch
Nekton
Demersal zone
Marine transgression
Cichowolski, Marcela
Uriz, Norberto Javier
Alfaro, Marta Beatríz
Galeano Inchausti, J.C.
Ascocerid cephalopods from the Hirnantian?-Llandovery stages of the southern Paraná Basin (Paraguay, South America): First record from high paleolatitudes
topic_facet Geología
Structural basin
Juvenile
Geology
Stage (stratigraphy)
Paleontology
Gondwana
Conch
Nekton
Demersal zone
Marine transgression
description Ascocerid cephalopods are described for the first time from high paleolatitudes of Gondwana. Studied material was collected from the Hirnantian?-Llandovery strata of the Eusebio Ayala and Vargas Pena formations, Parana Basin, southeastern Paraguay. The specimens are poorly preserved and were questionably assigned to the subfamily Probillingsitinae Flower, 1941, being undetermined at genus and species rank because diagnostic characters are not visible. A particular feature seen in our material is the presence of both parts of the ascocerid conch (the juvenile or cyrtocone and the mature or brevicone) joined together, which is a very rare condition in the known paleontological record. The specimens are interpreted as at a subadult stage of development because fully grown ascocerids would have lost the juvenile shell. A planktonic vertical migrant mode of life with a subvertical attitude is proposed for the juvenile, and a horizontal demersal nektonic mode for the adult form, as has been previously suggested. A subvertical orientation near the bottom is proposed for the subadult stage. We suggest that the immigration of ascocerids to southwestern Gondwana was possible through ocean currents that would carry the planktonic juveniles from low to high latitudes during the end-Ordovician postglacial transgression that flooded the intracratonic basins of the region.
format Articulo
Articulo
author Cichowolski, Marcela
Uriz, Norberto Javier
Alfaro, Marta Beatríz
Galeano Inchausti, J.C.
author_facet Cichowolski, Marcela
Uriz, Norberto Javier
Alfaro, Marta Beatríz
Galeano Inchausti, J.C.
author_sort Cichowolski, Marcela
title Ascocerid cephalopods from the Hirnantian?-Llandovery stages of the southern Paraná Basin (Paraguay, South America): First record from high paleolatitudes
title_short Ascocerid cephalopods from the Hirnantian?-Llandovery stages of the southern Paraná Basin (Paraguay, South America): First record from high paleolatitudes
title_full Ascocerid cephalopods from the Hirnantian?-Llandovery stages of the southern Paraná Basin (Paraguay, South America): First record from high paleolatitudes
title_fullStr Ascocerid cephalopods from the Hirnantian?-Llandovery stages of the southern Paraná Basin (Paraguay, South America): First record from high paleolatitudes
title_full_unstemmed Ascocerid cephalopods from the Hirnantian?-Llandovery stages of the southern Paraná Basin (Paraguay, South America): First record from high paleolatitudes
title_sort ascocerid cephalopods from the hirnantian?-llandovery stages of the southern paraná basin (paraguay, south america): first record from high paleolatitudes
publishDate 2018
url http://sedici.unlp.edu.ar/handle/10915/125863
work_keys_str_mv AT cichowolskimarcela ascoceridcephalopodsfromthehirnantianllandoverystagesofthesouthernparanabasinparaguaysouthamericafirstrecordfromhighpaleolatitudes
AT uriznorbertojavier ascoceridcephalopodsfromthehirnantianllandoverystagesofthesouthernparanabasinparaguaysouthamericafirstrecordfromhighpaleolatitudes
AT alfaromartabeatriz ascoceridcephalopodsfromthehirnantianllandoverystagesofthesouthernparanabasinparaguaysouthamericafirstrecordfromhighpaleolatitudes
AT galeanoinchaustijc ascoceridcephalopodsfromthehirnantianllandoverystagesofthesouthernparanabasinparaguaysouthamericafirstrecordfromhighpaleolatitudes
bdutipo_str Repositorios
_version_ 1764820452378673152

Ejemplares similares