O Big Bang dos dinossauros: como se tivessem sido plantados lá???

quarta-feira, abril 18, 2018

Dinosaur diversification linked with the Carnian Pluvial Episode

Massimo Bernardi, Piero Gianolla, Fabio Massimo Petti, Paolo Mietto & Michael J. Benton

Nature Communications volume 9, Article number: 1499 (2018)


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Palaeoecology Palaeontology

Received: 08 November 2017 Accepted: 27 March 2018

Published online: 16 April 2018


Abstract

Dinosaurs diversified in two steps during the Triassic. They originated about 245 Ma, during the recovery from the Permian-Triassic mass extinction, and then remained insignificant until they exploded in diversity and ecological importance during the Late Triassic. Hitherto, this Late Triassic explosion was poorly constrained and poorly dated. Here we provide evidence that it followed the Carnian Pluvial Episode (CPE), dated to 234–232 Ma, a time when climates switched from arid to humid and back to arid again. Our evidence comes from a combined analysis of skeletal evidence and footprint occurrences, and especially from the exquisitely dated ichnofaunas of the Italian Dolomites. These provide evidence of tetrapod faunal compositions through the Carnian and Norian, and show that dinosaur footprints appear exactly at the time of the CPE. We argue then that dinosaurs diversified explosively in the mid Carnian, at a time of major climate and floral change and the extinction of key herbivores, which the dinosaurs opportunistically replaced.

Acknowledgements

Matthias Franz, (Göttingen University) Edgar Nitsch (LGRB Freiburg) and Manfred Menning (GFZ Postdam) are thanked for useful information of the Germanic Basin; Nereo Preto, Manuel Rigo (Padova University) and Jacopo Dal Corso (Leeds University) are thanked for fruitful discussions on the CPE; and Guido Roghi (CNR-IRPI) for useful comments on pollen association. Hendrik Klein (SPM Neumarkt) and Marco Avanzini (MUSE Trento) provided useful comments on the tetrapod ichno-associations. P.G. thanks Marcello Caggiati (Ferrara University) for the palaeogeographic map of the upper Carnian. M.B. thanks La Sportiva for supporting field activities in the Dolomites. Funded in part by the NERC BETR grant NE/P013724/1 to M.J.B. and by PRIN 2010-2011 (Pr. No 20107ESMX9_004) to P.G.

Author information
Affiliations

MUSE—Museo delle Scienze, Corso del Lavoro e della Scienza 3, 38122, Trento, Italy
Massimo Bernardi & Fabio Massimo Petti
School of Earth Sciences, University of Bristol, Bristol, BS8 1RJ, UK
Massimo Bernardi & Michael J. Benton
Dipartimento di Fisica e Scienze della Terra, Università di Ferrara, via Saragat 1, 44100, Ferrara, Italy
Piero Gianolla
PaleoFactory, Dipartimento di Scienze della Terra, Sapienza Università di Roma, Piazzale Aldo Moro, 5, 00185, Rome, Italy
Fabio Massimo Petti
Dipartimento di Geoscienze, Università degli studi di Padova, via Gradenigo 6, I-35131, Padova, Italy
Paolo Mietto

Contributions
M.B. and P.G. designed the study. M.B., F.M.P., and M.J.B. developed the palaeontological parts of the study, while P.G. and P.M. contributed in the more geological sections. All authors interpreted the results. M.B. and P.G. led the writing of the paper and all other co-authors contributed to the final version.

Competing interests
The authors declare no competing interests.

Corresponding author
Correspondence to Massimo Bernardi.


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PERGUNTA CAUSTICANTE DESTE BLOGGER:

Novas formas "surgem abrupta e funcionalmente" no registro fóssil? De "não existem dinossauros" a "agora existem dinossauros"? E aí Darwin como é que fica o seu gradualismo???