Three-dimensionally integrated trace fossils from shallow-marine deposits in the lower cretaceous of the Neuquén Basin (Argentina): Hillichnus agrioensis isp. nov.

Acomplex trace fossil that requires a three-dimensional (3D) reconstruction is described and interpreted. The specimens studied are assigned to a new ichnospecies (Hillichnus agrioensis) of Hillichnus Bromley et al., 2003. Most of them are uncollectable and a compound iconotype was designed to chara...

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Detalles Bibliográficos
Autores principales: Pazos, P.J., Fernández, D.E.
Formato: JOUR
Materias:
Compound trace fossil
Hillichnus
Ichnology
Lower cretaceous
Neuquén basin
Shallow marine
Cretaceous
defecation
ichnology
marine sediment
morphology
taxonomy
three-dimensional modeling
trace fossil
type specimen
Argentina
Neuquen Basin
Bivalvia
Tellinidae
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_00015709_v60_n1_p105_Pazos
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id todo:paper_00015709_v60_n1_p105_Pazos
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spelling todo:paper_00015709_v60_n1_p105_Pazos2023-10-03T13:51:20Z Three-dimensionally integrated trace fossils from shallow-marine deposits in the lower cretaceous of the Neuquén Basin (Argentina): Hillichnus agrioensis isp. nov. Pazos, P.J. Fernández, D.E. Compound trace fossil Hillichnus Ichnology Lower cretaceous Neuquén basin Shallow marine Cretaceous defecation ichnology marine sediment morphology taxonomy three-dimensional modeling trace fossil type specimen Argentina Neuquen Basin Bivalvia Tellinidae Acomplex trace fossil that requires a three-dimensional (3D) reconstruction is described and interpreted. The specimens studied are assigned to a new ichnospecies (Hillichnus agrioensis) of Hillichnus Bromley et al., 2003. Most of them are uncollectable and a compound iconotype was designed to characterise the new ichnospecies. The three-dimensional trace fossil has been recorded in marginal-marine deposits close to the top of the Agrio Formation (Lower Cretaceous of Neuquén Basin, Argentina). The new ichnospecies shows a different pattern of feeding than H. lobosensis Bromley et al., 2003, and records defaecation downward in the deeper preservational level (level 4). Feather-like structures (level 2) that typify the ichnogenus also record the activity of an inhalant siphon and indicate a retractile movement. The vertical shafts (level 1) are scarcely recorded. Aligned double rings also document the infaunal habit of the tellinid bivalves that are considered the most likely producers of the trace. It is clear that when only level 2 is exposed, in some cases this form can be assigned to Jamesonichnites heinbergi Dam 1990a consequently, this ichnospecies is interconnected with more than one ichnogenus. Vertical projections recorded in branches differ from the type ichnospecies H. lobosensis Bromley et al., 2003. The occurrence in marginal-marine facies is congruent with the record of Jamesonichnites but not common in the type species and similar to those more frequent in deep-sea deposits (e.g. Polykampton alpinum Ooster, 1869). Fil:Pazos, P.J. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Fernández, D.E. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00015709_v60_n1_p105_Pazos
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Compound trace fossil
Hillichnus
Ichnology
Lower cretaceous
Neuquén basin
Shallow marine
Cretaceous
defecation
ichnology
marine sediment
morphology
taxonomy
three-dimensional modeling
trace fossil
type specimen
Argentina
Neuquen Basin
Bivalvia
Tellinidae
spellingShingle Compound trace fossil
Hillichnus
Ichnology
Lower cretaceous
Neuquén basin
Shallow marine
Cretaceous
defecation
ichnology
marine sediment
morphology
taxonomy
three-dimensional modeling
trace fossil
type specimen
Argentina
Neuquen Basin
Bivalvia
Tellinidae
Pazos, P.J.
Fernández, D.E.
Three-dimensionally integrated trace fossils from shallow-marine deposits in the lower cretaceous of the Neuquén Basin (Argentina): Hillichnus agrioensis isp. nov.
topic_facet Compound trace fossil
Hillichnus
Ichnology
Lower cretaceous
Neuquén basin
Shallow marine
Cretaceous
defecation
ichnology
marine sediment
morphology
taxonomy
three-dimensional modeling
trace fossil
type specimen
Argentina
Neuquen Basin
Bivalvia
Tellinidae
description Acomplex trace fossil that requires a three-dimensional (3D) reconstruction is described and interpreted. The specimens studied are assigned to a new ichnospecies (Hillichnus agrioensis) of Hillichnus Bromley et al., 2003. Most of them are uncollectable and a compound iconotype was designed to characterise the new ichnospecies. The three-dimensional trace fossil has been recorded in marginal-marine deposits close to the top of the Agrio Formation (Lower Cretaceous of Neuquén Basin, Argentina). The new ichnospecies shows a different pattern of feeding than H. lobosensis Bromley et al., 2003, and records defaecation downward in the deeper preservational level (level 4). Feather-like structures (level 2) that typify the ichnogenus also record the activity of an inhalant siphon and indicate a retractile movement. The vertical shafts (level 1) are scarcely recorded. Aligned double rings also document the infaunal habit of the tellinid bivalves that are considered the most likely producers of the trace. It is clear that when only level 2 is exposed, in some cases this form can be assigned to Jamesonichnites heinbergi Dam 1990a consequently, this ichnospecies is interconnected with more than one ichnogenus. Vertical projections recorded in branches differ from the type ichnospecies H. lobosensis Bromley et al., 2003. The occurrence in marginal-marine facies is congruent with the record of Jamesonichnites but not common in the type species and similar to those more frequent in deep-sea deposits (e.g. Polykampton alpinum Ooster, 1869).
format JOUR
author Pazos, P.J.
Fernández, D.E.
author_facet Pazos, P.J.
Fernández, D.E.
author_sort Pazos, P.J.
title Three-dimensionally integrated trace fossils from shallow-marine deposits in the lower cretaceous of the Neuquén Basin (Argentina): Hillichnus agrioensis isp. nov.
title_short Three-dimensionally integrated trace fossils from shallow-marine deposits in the lower cretaceous of the Neuquén Basin (Argentina): Hillichnus agrioensis isp. nov.
title_full Three-dimensionally integrated trace fossils from shallow-marine deposits in the lower cretaceous of the Neuquén Basin (Argentina): Hillichnus agrioensis isp. nov.
title_fullStr Three-dimensionally integrated trace fossils from shallow-marine deposits in the lower cretaceous of the Neuquén Basin (Argentina): Hillichnus agrioensis isp. nov.
title_full_unstemmed Three-dimensionally integrated trace fossils from shallow-marine deposits in the lower cretaceous of the Neuquén Basin (Argentina): Hillichnus agrioensis isp. nov.
title_sort three-dimensionally integrated trace fossils from shallow-marine deposits in the lower cretaceous of the neuquén basin (argentina): hillichnus agrioensis isp. nov.
url http://hdl.handle.net/20.500.12110/paper_00015709_v60_n1_p105_Pazos
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AT fernandezde threedimensionallyintegratedtracefossilsfromshallowmarinedepositsinthelowercretaceousoftheneuquenbasinargentinahillichnusagrioensisispnov
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