Ichnological evidence for meiofaunal bilaterians from the terminal Ediacaran and earliest Cambrian of Brazil

The evolutionary events during the Ediacaran–Cambrian transition (~541 Myr ago) are unparalleled in Earth history. The fossil record suggests that most extant animal phyla appeared in a geologically brief interval, with the oldest unequivocal bilaterian body fossils found in the Early Cambrian. Mole...

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প্রধান লেখক: Parry, LA, Boggiani, PC, Condon, DJ, Garwood, RJ, Leme, JDM, McIlroy, D, Brasier, MD, Trindade, R, Campanha, GAC, Pacheco, MLAF, Diniz, CQC, Liu, AG
বিন্যাস: Journal article
ভাষা:English
প্রকাশিত: Nature Research 2017
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author Parry, LA
Boggiani, PC
Condon, DJ
Garwood, RJ
Leme, JDM
McIlroy, D
Brasier, MD
Trindade, R
Campanha, GAC
Pacheco, MLAF
Diniz, CQC
Liu, AG
author_facet Parry, LA
Boggiani, PC
Condon, DJ
Garwood, RJ
Leme, JDM
McIlroy, D
Brasier, MD
Trindade, R
Campanha, GAC
Pacheco, MLAF
Diniz, CQC
Liu, AG
author_sort Parry, LA
collection OXFORD
description The evolutionary events during the Ediacaran–Cambrian transition (~541 Myr ago) are unparalleled in Earth history. The fossil record suggests that most extant animal phyla appeared in a geologically brief interval, with the oldest unequivocal bilaterian body fossils found in the Early Cambrian. Molecular clocks and biomarkers provide independent estimates for the timing of animal origins, and both suggest a cryptic Neoproterozoic history for Metazoa that extends considerably beyond the Cambrian fossil record. We report an assemblage of ichnofossils from Ediacaran–Cambrian siltstones in Brazil, alongside U–Pb radioisotopic dates that constrain the age of the oldest specimens to 555–542 Myr. X-ray microtomography reveals three-dimensionally preserved traces ranging from 50 to 600 μm in diameter, indicative of small-bodied, meiofaunal tracemakers. Burrow morphologies suggest they were created by a nematoid-like organism that used undulating locomotion to move through the sediment. This assemblage demonstrates animal–sediment interactions in the latest Ediacaran period, and provides the oldest known fossil evidence for meiofaunal bilaterians. Our discovery highlights meiofaunal ichnofossils as a hitherto unexplored window for tracking animal evolution in deep time, and reveals that both meiofaunal and macrofaunal bilaterians began to explore infaunal niches during the late Ediacaran.
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spelling oxford-uuid:fab0656d-835b-4e57-b9c1-c60e71a9e9842022-03-27T13:07:58ZIchnological evidence for meiofaunal bilaterians from the terminal Ediacaran and earliest Cambrian of BrazilJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:fab0656d-835b-4e57-b9c1-c60e71a9e984EnglishSymplectic ElementsNature Research2017Parry, LABoggiani, PCCondon, DJGarwood, RJLeme, JDMMcIlroy, DBrasier, MDTrindade, RCampanha, GACPacheco, MLAFDiniz, CQCLiu, AGThe evolutionary events during the Ediacaran–Cambrian transition (~541 Myr ago) are unparalleled in Earth history. The fossil record suggests that most extant animal phyla appeared in a geologically brief interval, with the oldest unequivocal bilaterian body fossils found in the Early Cambrian. Molecular clocks and biomarkers provide independent estimates for the timing of animal origins, and both suggest a cryptic Neoproterozoic history for Metazoa that extends considerably beyond the Cambrian fossil record. We report an assemblage of ichnofossils from Ediacaran–Cambrian siltstones in Brazil, alongside U–Pb radioisotopic dates that constrain the age of the oldest specimens to 555–542 Myr. X-ray microtomography reveals three-dimensionally preserved traces ranging from 50 to 600 μm in diameter, indicative of small-bodied, meiofaunal tracemakers. Burrow morphologies suggest they were created by a nematoid-like organism that used undulating locomotion to move through the sediment. This assemblage demonstrates animal–sediment interactions in the latest Ediacaran period, and provides the oldest known fossil evidence for meiofaunal bilaterians. Our discovery highlights meiofaunal ichnofossils as a hitherto unexplored window for tracking animal evolution in deep time, and reveals that both meiofaunal and macrofaunal bilaterians began to explore infaunal niches during the late Ediacaran.
spellingShingle Parry, LA
Boggiani, PC
Condon, DJ
Garwood, RJ
Leme, JDM
McIlroy, D
Brasier, MD
Trindade, R
Campanha, GAC
Pacheco, MLAF
Diniz, CQC
Liu, AG
Ichnological evidence for meiofaunal bilaterians from the terminal Ediacaran and earliest Cambrian of Brazil
title Ichnological evidence for meiofaunal bilaterians from the terminal Ediacaran and earliest Cambrian of Brazil
title_full Ichnological evidence for meiofaunal bilaterians from the terminal Ediacaran and earliest Cambrian of Brazil
title_fullStr Ichnological evidence for meiofaunal bilaterians from the terminal Ediacaran and earliest Cambrian of Brazil
title_full_unstemmed Ichnological evidence for meiofaunal bilaterians from the terminal Ediacaran and earliest Cambrian of Brazil
title_short Ichnological evidence for meiofaunal bilaterians from the terminal Ediacaran and earliest Cambrian of Brazil
title_sort ichnological evidence for meiofaunal bilaterians from the terminal ediacaran and earliest cambrian of brazil
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