The genus steinmanella crickmay (Bivalvia) in the transition between the vaca muerta and mulichinco formations, early Valanginian, Neuquen Basin, Argentina

The genus Steinmanella Crickmay is recorded in several Lower Cretaceous marine units of the Neuquen Basin. It is particularly abundant at the transition between the Vaca Muerta and Mulichinco formations. This paper presents a taxonomic revision of this fauna, discusses the stratigraphic range of eac...

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Autores principales:	Luci, L., Lazo, D.G.
Formato:	JOUR
Materias:	Mulichinco Formation Neuquén Province Steinmanella Trigonioida Vaca Muerta Formation Valanginian ammonite bivalve lithofacies morphology new species ornamentation shale siltstone specimen bank taxonomy Argentina Neuquen Basin Ammonoidea Bivalvia Carinae
Acceso en línea:	http://hdl.handle.net/20.500.12110/paper_00027014_v49_n1_p96_Luci
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

id	todo:paper_00027014_v49_n1_p96_Luci
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spelling	todo:paper_00027014_v49_n1_p96_Luci2023-10-03T13:53:12Z The genus steinmanella crickmay (Bivalvia) in the transition between the vaca muerta and mulichinco formations, early Valanginian, Neuquen Basin, Argentina Luci, L. Lazo, D.G. Mulichinco Formation Neuquén Province Steinmanella Trigonioida Vaca Muerta Formation Valanginian ammonite bivalve lithofacies morphology new species ornamentation shale siltstone specimen bank taxonomy Valanginian Argentina Neuquen Basin Ammonoidea Bivalvia Carinae Steinmanella Trigonioida The genus Steinmanella Crickmay is recorded in several Lower Cretaceous marine units of the Neuquen Basin. It is particularly abundant at the transition between the Vaca Muerta and Mulichinco formations. This paper presents a taxonomic revision of this fauna, discusses the stratigraphic range of each species, and describes and interprets the associated lithofacies based on detailed field sections, newly collected specimens and revision of previous fossil collections. Four sections were measured in northern Neuquen comprising the upper beds of the Vaca Muerta Formation and the lower ones of the Mulichinco Formation. The Steinmanella fauna was dated accurately on the basis of a precise ammonoid zonation. The species were found in the Neocomites wichmanni and Lissonia riveroi zones of early Valanginian age. Specimens were collected in situ from dark grey shales, alternating siltstones, wackestones and mudstones, and rudstones. Three species were identified: Steinmanella curacoensis (Weaver), S. quintucoensis (Weaver), and S. subquadrata sp. nov. Steinmanella curacoensis has an oval outline, poor demarcation of carinae, flank and corselet ribs partially intercalated at the median part of the valve, and oval escutcheon. Steinmanella quintucoensis has a furrow below the marginal carina, subrectangular outline, robustly tuberculated flank ribs, and lanceolate escutcheon. Steinmanella subquadrata sp. nov. has a subquadrate outline, well-marked carinae, and oval escutcheon ornamented with thin ribs and small elongated tubercles. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00027014_v49_n1_p96_Luci
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	Mulichinco Formation Neuquén Province Steinmanella Trigonioida Vaca Muerta Formation Valanginian ammonite bivalve lithofacies morphology new species ornamentation shale siltstone specimen bank taxonomy Valanginian Argentina Neuquen Basin Ammonoidea Bivalvia Carinae Steinmanella Trigonioida
spellingShingle	Mulichinco Formation Neuquén Province Steinmanella Trigonioida Vaca Muerta Formation Valanginian ammonite bivalve lithofacies morphology new species ornamentation shale siltstone specimen bank taxonomy Valanginian Argentina Neuquen Basin Ammonoidea Bivalvia Carinae Steinmanella Trigonioida Luci, L. Lazo, D.G. The genus steinmanella crickmay (Bivalvia) in the transition between the vaca muerta and mulichinco formations, early Valanginian, Neuquen Basin, Argentina
topic_facet	Mulichinco Formation Neuquén Province Steinmanella Trigonioida Vaca Muerta Formation Valanginian ammonite bivalve lithofacies morphology new species ornamentation shale siltstone specimen bank taxonomy Valanginian Argentina Neuquen Basin Ammonoidea Bivalvia Carinae Steinmanella Trigonioida
description	The genus Steinmanella Crickmay is recorded in several Lower Cretaceous marine units of the Neuquen Basin. It is particularly abundant at the transition between the Vaca Muerta and Mulichinco formations. This paper presents a taxonomic revision of this fauna, discusses the stratigraphic range of each species, and describes and interprets the associated lithofacies based on detailed field sections, newly collected specimens and revision of previous fossil collections. Four sections were measured in northern Neuquen comprising the upper beds of the Vaca Muerta Formation and the lower ones of the Mulichinco Formation. The Steinmanella fauna was dated accurately on the basis of a precise ammonoid zonation. The species were found in the Neocomites wichmanni and Lissonia riveroi zones of early Valanginian age. Specimens were collected in situ from dark grey shales, alternating siltstones, wackestones and mudstones, and rudstones. Three species were identified: Steinmanella curacoensis (Weaver), S. quintucoensis (Weaver), and S. subquadrata sp. nov. Steinmanella curacoensis has an oval outline, poor demarcation of carinae, flank and corselet ribs partially intercalated at the median part of the valve, and oval escutcheon. Steinmanella quintucoensis has a furrow below the marginal carina, subrectangular outline, robustly tuberculated flank ribs, and lanceolate escutcheon. Steinmanella subquadrata sp. nov. has a subquadrate outline, well-marked carinae, and oval escutcheon ornamented with thin ribs and small elongated tubercles.
format	JOUR
author	Luci, L. Lazo, D.G.
author_facet	Luci, L. Lazo, D.G.
author_sort	Luci, L.
title	The genus steinmanella crickmay (Bivalvia) in the transition between the vaca muerta and mulichinco formations, early Valanginian, Neuquen Basin, Argentina
title_short	The genus steinmanella crickmay (Bivalvia) in the transition between the vaca muerta and mulichinco formations, early Valanginian, Neuquen Basin, Argentina
title_full	The genus steinmanella crickmay (Bivalvia) in the transition between the vaca muerta and mulichinco formations, early Valanginian, Neuquen Basin, Argentina
title_fullStr	The genus steinmanella crickmay (Bivalvia) in the transition between the vaca muerta and mulichinco formations, early Valanginian, Neuquen Basin, Argentina
title_full_unstemmed	The genus steinmanella crickmay (Bivalvia) in the transition between the vaca muerta and mulichinco formations, early Valanginian, Neuquen Basin, Argentina
title_sort	genus steinmanella crickmay (bivalvia) in the transition between the vaca muerta and mulichinco formations, early valanginian, neuquen basin, argentina
url	http://hdl.handle.net/20.500.12110/paper_00027014_v49_n1_p96_Luci
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The genus steinmanella crickmay (Bivalvia) in the transition between the vaca muerta and mulichinco formations, early Valanginian, Neuquen Basin, Argentina

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