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The precise temporal calibration of dinosaur origins.
Proc Natl Acad Sci U S A. 2016 Jan 19; 113(3):509-13.PN

Abstract

Dinosaurs have been major components of ecosystems for over 200 million years. Although different macroevolutionary scenarios exist to explain the Triassic origin and subsequent rise to dominance of dinosaurs and their closest relatives (dinosauromorphs), all lack critical support from a precise biostratigraphically independent temporal framework. The absence of robust geochronologic age control for comparing alternative scenarios makes it impossible to determine if observed faunal differences vary across time, space, or a combination of both. To better constrain the origin of dinosaurs, we produced radioisotopic ages for the Argentinian Chañares Formation, which preserves a quintessential assemblage of dinosaurian precursors (early dinosauromorphs) just before the first dinosaurs. Our new high-precision chemical abrasion thermal ionization mass spectrometry (CA-TIMS) U-Pb zircon ages reveal that the assemblage is early Carnian (early Late Triassic), 5- to 10-Ma younger than previously thought. Combined with other geochronologic data from the same basin, we constrain the rate of dinosaur origins, demonstrating their relatively rapid origin in a less than 5-Ma interval, thus halving the temporal gap between assemblages containing only dinosaur precursors and those with early dinosaurs. After their origin, dinosaurs only gradually dominated mid- to high-latitude terrestrial ecosystems millions of years later, closer to the Triassic-Jurassic boundary.

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Authors+Show Affiliations

Marsicano CA
Departamento de Ciencias Geológicas, Instituto de Estudios Andinos-Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires C1428EHA, Argentina;
Irmis RB
Natural History Museum of Utah, University of Utah, Salt Lake City, UT 84108-1214; Department of Geology & Geophysics, University of Utah, Salt Lake City, UT 84112-0102; irmis@umnh.utah.edu.
Mancuso AC
Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales, Centro Científico y Tecnológico-Consejo Nacional de Investigaciones Científicas y Técnicas-Mendoza, Mendoza CC330, Argentina;
Mundil R
Berkeley Geochronology Center, Berkeley, CA 94709;
Chemale F
Instituto de Geociências, Universidade de Brasília, Brasília-DF 70864-050, Brazil.

MeSH

AnimalsArgentinaBiological EvolutionCalibrationDinosaursGeographyTime Factors

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

26644579

Citation

Marsicano, Claudia A., et al. "The Precise Temporal Calibration of Dinosaur Origins." Proceedings of the National Academy of Sciences of the United States of America, vol. 113, no. 3, 2016, pp. 509-13.
Marsicano CA, Irmis RB, Mancuso AC, et al. The precise temporal calibration of dinosaur origins. Proc Natl Acad Sci U S A. 2016;113(3):509-13.
Marsicano, C. A., Irmis, R. B., Mancuso, A. C., Mundil, R., & Chemale, F. (2016). The precise temporal calibration of dinosaur origins. Proceedings of the National Academy of Sciences of the United States of America, 113(3), 509-13. https://doi.org/10.1073/pnas.1512541112
Marsicano CA, et al. The Precise Temporal Calibration of Dinosaur Origins. Proc Natl Acad Sci U S A. 2016 Jan 19;113(3):509-13. PubMed PMID: 26644579.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - The precise temporal calibration of dinosaur origins. AU - Marsicano,Claudia A, AU - Irmis,Randall B, AU - Mancuso,Adriana C, AU - Mundil,Roland, AU - Chemale,Farid, Y1 - 2015/12/07/ PY - 2015/12/9/entrez PY - 2015/12/9/pubmed PY - 2016/6/14/medline KW - Chañares Formation KW - Triassic KW - biostratigraphy KW - dinosaur origins KW - geochronology SP - 509 EP - 13 JF - Proceedings of the National Academy of Sciences of the United States of America JO - Proc Natl Acad Sci U S A VL - 113 IS - 3 N2 - Dinosaurs have been major components of ecosystems for over 200 million years. Although different macroevolutionary scenarios exist to explain the Triassic origin and subsequent rise to dominance of dinosaurs and their closest relatives (dinosauromorphs), all lack critical support from a precise biostratigraphically independent temporal framework. The absence of robust geochronologic age control for comparing alternative scenarios makes it impossible to determine if observed faunal differences vary across time, space, or a combination of both. To better constrain the origin of dinosaurs, we produced radioisotopic ages for the Argentinian Chañares Formation, which preserves a quintessential assemblage of dinosaurian precursors (early dinosauromorphs) just before the first dinosaurs. Our new high-precision chemical abrasion thermal ionization mass spectrometry (CA-TIMS) U-Pb zircon ages reveal that the assemblage is early Carnian (early Late Triassic), 5- to 10-Ma younger than previously thought. Combined with other geochronologic data from the same basin, we constrain the rate of dinosaur origins, demonstrating their relatively rapid origin in a less than 5-Ma interval, thus halving the temporal gap between assemblages containing only dinosaur precursors and those with early dinosaurs. After their origin, dinosaurs only gradually dominated mid- to high-latitude terrestrial ecosystems millions of years later, closer to the Triassic-Jurassic boundary. SN - 1091-6490 UR - https://www.unboundmedicine.com/medline/citation/26644579/The_precise_temporal_calibration_of_dinosaur_origins_ DB - PRIME DP - Unbound Medicine ER -