Ordovician sponge spicules from Spitsbergen, Nevada and Newfoundland: new evidence for the Hexactinellida early differentiation

Autores
Carrera, Marcelo G.; Maletz, J.
Año de publicación
2010
Idioma
inglés
Tipo de recurso
documento de conferencia
Estado
versión publicada
Descripción
Division of Hexactinellida into the subclasses Amphidiscophora and Hexasterophora is now generally accepted due to their very distinct types of microscleres, namely amphidiscs and hexasters, respectively. Microscleres of this type have been recognized in the Lower Paleozoic. We examined exceptionally well preserved spicule assemblages from three particular Lower to Middle Ordovician localities: Spitsb ergen (Floian-Dapingian), Nevada (Vinini Formation, Dapingian) and Newfoundland (Cow Head Formation, Tremadocian and Table Head Group, Darriwilian). The presence of hexaster-type spicules, hemidiscs and amphidiscs is reported here. The hexasters are certainly documented from the Lower Ordovician and possibly from the Cambrian. Although hemidiscs were reported from the Lower Ordovician, oldest true amphidiscs were reported from the Silurian. The occurrence of amphidiscs in these localities implies that the Amphidiscophora can be certainly traced back to the Lower Ordovician. The occurrence of five different types of scopules (typical microscleres of the Sceptrulophora) significantly increases the diversity of this group in the Ordovician. The collection also includes important and variable types of hexactinellid spicules (pinular hexactines and pentactines, equinate hexactines, tauactins and inflated pentactines, and different types of uncinate monactins), calcareous heteractines, and different types of demosponge spicules (oxiasters, C-shaped sigmata, trianes and dendroclones).
Sesiones libres
Facultad de Ciencias Naturales y Museo
Materia
Ciencias Naturales
Paleontología
Ordovician sponge spicules
Spitsbergen, Nevada
Newfoundland
Nivel de accesibilidad
acceso abierto
Condiciones de uso
http://creativecommons.org/licenses/by-nc-sa/4.0/
Repositorio
SEDICI (UNLP)
Institución
Universidad Nacional de La Plata
OAI Identificador
oai:sedici.unlp.edu.ar:10915/16830

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spelling Ordovician sponge spicules from Spitsbergen, Nevada and Newfoundland: new evidence for the Hexactinellida early differentiationCarrera, Marcelo G.Maletz, J.Ciencias NaturalesPaleontologíaOrdovician sponge spiculesSpitsbergen, NevadaNewfoundlandDivision of Hexactinellida into the subclasses Amphidiscophora and Hexasterophora is now generally accepted due to their very distinct types of microscleres, namely amphidiscs and hexasters, respectively. Microscleres of this type have been recognized in the Lower Paleozoic. We examined exceptionally well preserved spicule assemblages from three particular Lower to Middle Ordovician localities: Spitsb ergen (Floian-Dapingian), Nevada (Vinini Formation, Dapingian) and Newfoundland (Cow Head Formation, Tremadocian and Table Head Group, Darriwilian). The presence of hexaster-type spicules, hemidiscs and amphidiscs is reported here. The hexasters are certainly documented from the Lower Ordovician and possibly from the Cambrian. Although hemidiscs were reported from the Lower Ordovician, oldest true amphidiscs were reported from the Silurian. The occurrence of amphidiscs in these localities implies that the Amphidiscophora can be certainly traced back to the Lower Ordovician. The occurrence of five different types of scopules (typical microscleres of the Sceptrulophora) significantly increases the diversity of this group in the Ordovician. The collection also includes important and variable types of hexactinellid spicules (pinular hexactines and pentactines, equinate hexactines, tauactins and inflated pentactines, and different types of uncinate monactins), calcareous heteractines, and different types of demosponge spicules (oxiasters, C-shaped sigmata, trianes and dendroclones).Sesiones libresFacultad de Ciencias Naturales y Museo2010info:eu-repo/semantics/conferenceObjectinfo:eu-repo/semantics/publishedVersionResumenhttp://purl.org/coar/resource_type/c_5794info:ar-repo/semantics/documentoDeConferenciaapplication/pdfhttp://sedici.unlp.edu.ar/handle/10915/16830enginfo:eu-repo/semantics/altIdentifier/isbn/978-987-95849-7-2info:eu-repo/semantics/reference/hdl/10915/25738info:eu-repo/semantics/openAccesshttp://creativecommons.org/licenses/by-nc-sa/4.0/Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)reponame:SEDICI (UNLP)instname:Universidad Nacional de La Platainstacron:UNLP2025-09-03T10:25:54Zoai:sedici.unlp.edu.ar:10915/16830Institucionalhttp://sedici.unlp.edu.ar/Universidad públicaNo correspondehttp://sedici.unlp.edu.ar/oai/snrdalira@sedici.unlp.edu.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:13292025-09-03 10:25:54.867SEDICI (UNLP) - Universidad Nacional de La Platafalse
dc.title.none.fl_str_mv Ordovician sponge spicules from Spitsbergen, Nevada and Newfoundland: new evidence for the Hexactinellida early differentiation
title Ordovician sponge spicules from Spitsbergen, Nevada and Newfoundland: new evidence for the Hexactinellida early differentiation
spellingShingle Ordovician sponge spicules from Spitsbergen, Nevada and Newfoundland: new evidence for the Hexactinellida early differentiation
Carrera, Marcelo G.
Ciencias Naturales
Paleontología
Ordovician sponge spicules
Spitsbergen, Nevada
Newfoundland
title_short Ordovician sponge spicules from Spitsbergen, Nevada and Newfoundland: new evidence for the Hexactinellida early differentiation
title_full Ordovician sponge spicules from Spitsbergen, Nevada and Newfoundland: new evidence for the Hexactinellida early differentiation
title_fullStr Ordovician sponge spicules from Spitsbergen, Nevada and Newfoundland: new evidence for the Hexactinellida early differentiation
title_full_unstemmed Ordovician sponge spicules from Spitsbergen, Nevada and Newfoundland: new evidence for the Hexactinellida early differentiation
title_sort Ordovician sponge spicules from Spitsbergen, Nevada and Newfoundland: new evidence for the Hexactinellida early differentiation
dc.creator.none.fl_str_mv Carrera, Marcelo G.
Maletz, J.
author Carrera, Marcelo G.
author_facet Carrera, Marcelo G.
Maletz, J.
author_role author
author2 Maletz, J.
author2_role author
dc.subject.none.fl_str_mv Ciencias Naturales
Paleontología
Ordovician sponge spicules
Spitsbergen, Nevada
Newfoundland
topic Ciencias Naturales
Paleontología
Ordovician sponge spicules
Spitsbergen, Nevada
Newfoundland
dc.description.none.fl_txt_mv Division of Hexactinellida into the subclasses Amphidiscophora and Hexasterophora is now generally accepted due to their very distinct types of microscleres, namely amphidiscs and hexasters, respectively. Microscleres of this type have been recognized in the Lower Paleozoic. We examined exceptionally well preserved spicule assemblages from three particular Lower to Middle Ordovician localities: Spitsb ergen (Floian-Dapingian), Nevada (Vinini Formation, Dapingian) and Newfoundland (Cow Head Formation, Tremadocian and Table Head Group, Darriwilian). The presence of hexaster-type spicules, hemidiscs and amphidiscs is reported here. The hexasters are certainly documented from the Lower Ordovician and possibly from the Cambrian. Although hemidiscs were reported from the Lower Ordovician, oldest true amphidiscs were reported from the Silurian. The occurrence of amphidiscs in these localities implies that the Amphidiscophora can be certainly traced back to the Lower Ordovician. The occurrence of five different types of scopules (typical microscleres of the Sceptrulophora) significantly increases the diversity of this group in the Ordovician. The collection also includes important and variable types of hexactinellid spicules (pinular hexactines and pentactines, equinate hexactines, tauactins and inflated pentactines, and different types of uncinate monactins), calcareous heteractines, and different types of demosponge spicules (oxiasters, C-shaped sigmata, trianes and dendroclones).
Sesiones libres
Facultad de Ciencias Naturales y Museo
description Division of Hexactinellida into the subclasses Amphidiscophora and Hexasterophora is now generally accepted due to their very distinct types of microscleres, namely amphidiscs and hexasters, respectively. Microscleres of this type have been recognized in the Lower Paleozoic. We examined exceptionally well preserved spicule assemblages from three particular Lower to Middle Ordovician localities: Spitsb ergen (Floian-Dapingian), Nevada (Vinini Formation, Dapingian) and Newfoundland (Cow Head Formation, Tremadocian and Table Head Group, Darriwilian). The presence of hexaster-type spicules, hemidiscs and amphidiscs is reported here. The hexasters are certainly documented from the Lower Ordovician and possibly from the Cambrian. Although hemidiscs were reported from the Lower Ordovician, oldest true amphidiscs were reported from the Silurian. The occurrence of amphidiscs in these localities implies that the Amphidiscophora can be certainly traced back to the Lower Ordovician. The occurrence of five different types of scopules (typical microscleres of the Sceptrulophora) significantly increases the diversity of this group in the Ordovician. The collection also includes important and variable types of hexactinellid spicules (pinular hexactines and pentactines, equinate hexactines, tauactins and inflated pentactines, and different types of uncinate monactins), calcareous heteractines, and different types of demosponge spicules (oxiasters, C-shaped sigmata, trianes and dendroclones).
publishDate 2010
dc.date.none.fl_str_mv 2010
dc.type.none.fl_str_mv info:eu-repo/semantics/conferenceObject
info:eu-repo/semantics/publishedVersion
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dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/isbn/978-987-95849-7-2
info:eu-repo/semantics/reference/hdl/10915/25738
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-sa/4.0/
Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
eu_rights_str_mv openAccess
rights_invalid_str_mv http://creativecommons.org/licenses/by-nc-sa/4.0/
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