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Fwd: Theropod tooth enamel with seasonal patterns in oxygen isotope composition



Apparently this post did not go through. I'll try again...

---------- Forwarded message ----------
From: Ben Creisler <bcreisler@gmail.com>
Date: Tue, Jan 26, 2016 at 12:11 PM
Subject: Theropod tooth enamel with seasonal patterns in oxygen
isotope composition
To: dinosaur@usc.edu


Ben Creisler
bcreisler@gmail.com


A new paper:

Jean Goedert, Romain Amiot, Larbi Boudad, Eric Buffetaut, François
Fourel, Pascal Godefroit, Nao Kusuhashi, Varavudh Suteethorn, Haiyan
Tong, Mahito Watabe, and Christophe Lécuyer (2016)
Preliminary investigation of seasonal patterns recorded in the oxygen
isotope compositions of theropod dinosaur tooth enamel.
PALAIOS 31(1): 10-19
doi:10.2110/palo.2015.018
http://www.bioone.org/doi/abs/10.2110/palo.2015.018
http://palaios.geoscienceworld.org/content/31/1/10.abstract



Oxygen isotope compositions of tooth enamel increments in theropod
dinosaurs are investigated as potential proxies of climate
seasonality. Six teeth of large carnivorous theropods collected from
four Cretaceous formations deposited under contrasted climates have
been sampled. These teeth have been analyzed for the oxygen isotope
compositions of their apatite phosphate (δ18Op) through incremental
sampling performed along the major growth axis. Significant
fluctuations in oxygen isotope compositions along the growth axis of
each tooth are observed and interpreted as reflecting seasonality in
ingested local surface water δ18Ow values. Fluctuations in δ18Op
values of theropod teeth from the Aptian of Thailand and Cenomanian of
Morocco vary similarly to meteoric water δ18Omw values occurring today
in sub-tropical regions subjected to large seasonal amounts of
precipitations. A dinosaur tooth recovered from the more inland and
mid-latitude Nemegt Formation of Mongolia shows a seasonal pattern
similar to present-day cold temperate and continental climate.
Finally, the high latitude and coastal Kakanaut Formation (Russia)
experienced strongly dampened seasonal variations, most likely due to
the influence of warm Pacific oceanic currents. Such conditions occur
today in high latitude regions submitted to marine influence. These
results further highlight the potential of using the oxygen isotope
compositions of large theropod teeth to reconstruct past seasonal
variations of terrestrial climates. Increased knowledge of past
seasonality may help to better understand the complex interactions
between climate and the dynamics of land biodiversity in terms of
ecological adaptations, biogeography and the evolutionary history of
organisms.