Pushing the limits of bioapatite clumped isotope analysis: resolving endo- from ectothermy in mosasaurs
Mineralogy, Petrology and Geochemistry
Final Report Abstract
This project originally aimed at the reduction of sample size for D47 analysis of carbonatebearing bioapatites and the reconstruction of mosasaur body temperature. As intended, we were successful in reducing the sample size required for bioapatite D47 analysis by a factor of 40 by setting up a Kiel IV-based CO2 extraction methodology. Due to unforeseen delays in the delivery of samples, in the elaboration of the CO2 extraction methodology and in the identification of well-preserved mosasaur teeth, all of which largely arose from the Corona crisis, we were, however, not able to apply our new methodology to D47 analysis of mosasaur teeth. Directly after recognizing these limitations, we replaced the goal of mosasaur body temperature reconstruction by a more feasible endeavour, the reconstruction of the (thermo)physiology of dinosoaurs. For this purpose, we analyzed eggshells from Troodon (a non-avian theropod very close to the origin of birds), modern birds and reptiles for their dual clumped (D47, D48) isotope composition. We confirmed that Troodon were heterothermic endotherms, being able to reduce their body temperature from 42°C to 29°C. Unlike modern birds, Troodon share an equilibrium D48 signature in their eggshells with modern reptiles. These results strongly imply that Troodon – like reptiles – had two functional ovaries, so that they had no need for rapid eggshell calcification. The onset of rapid eggshell calcification only occurred afterwards in the lineage of birds, going along with the loss of one functional ovary. The relationship between the extent of disequilibrium D48 and eggshell clutch mass per body mass characteristic of modern birds and reptiles, in combination with the total number of eggs observed in Troodon nests, suggests Troodon laid four to six eggs per clutch and shared communal nests.
Publications
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Clumped isotope analysis of (bio)apatite using a Kiel IV device in long‐integration dual‐inlet mode. Rapid Communications in Mass Spectrometry, 37(24).
Tagliavento, Mattia; Hofmann, Sven; Böttcher, Michael Ernst; Peltz, Markus & Fiebig, Jens
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Evidence for heterothermic endothermy and reptile-like eggshell mineralization inTroodon, a non-avian maniraptoran theropod. Proceedings of the National Academy of Sciences, 120(15).
Tagliavento, Mattia; Davies, Amelia J.; Bernecker, Miguel; Staudigel, Philip T.; Dawson, Robin R.; Dietzel, Martin; Götschl, Katja; Guo, Weifu; Schulp, Anne S.; Therrien, François; Zelenitsky, Darla K.; Gerdes, Axel; Müller, Wolfgang & Fiebig, Jens
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Proto-monsoon rainfall and greening in Central Asia due to extreme early Eocene warmth. Nature Geoscience, 17(2), 158-164.
Meijer, Niels; Licht, Alexis; Woutersen, Amber; Hoorn, Carina; Robin-Champigneul, Faez; Rohrmann, Alexander; Tagliavento, Mattia; Brugger, Julia; Kelemen, Fanni D.; Schauer, Andrew J.; Hren, Micheal T.; Sun, Aijun; Fiebig, Jens; Mulch, Andreas & Dupont-Nivet, Guillaume
