Dental histology of three notosuchians (Crocodylomorpha) from the Bauru Group, Upper Cretaceous, South-eastern Brazil

ABSTRACT

The Upper Cretaceous Bauru Group deposits furnished several species of Crocodylomorpha, especially notosuchians. However, little is known about the feeding habits of this diverse group of crocodylomorphs. The dental histology is a destructive approach that can provide important information on tooth growth and feeding habits of fossil vertebrates. So far, few studies dealt with crocodylomorph dental histology and the ones available mainly focused on fossil and living neosuchians. In this work, we analyse the dental histology of three notosuchians commonly found in the Upper Cretaceous rocks of the Bauru Group: juvenile and adult Baurusuchidae, a large Sphagesauridae, and Mariliasuchus amarali. Our analyses indicate that tooth formation varied in these three taxa. In Mariliasuchus, a tooth took less than 2 months to be completely grown. On the other hand, in Sphagesauridae and Baurusuchidae, the tooth formation could take about 6 months to be completed. Mariliasuchus and Sphagesauridae have proportionally thicker enamel in comparison to Baurusuchidae. Additionally, the enamel thickness and its substantial development in the chewing area in Sphagesauridae indicate that apical advanced notosuchians are more adapted to process food items than more basal forms like Mariliasuchus.

KEYWORDS:

• Notosuchia
• dental histology
• Bauru Group
• Cretaceous
• von Ebner lines

Acknowledgments

We thank the laboratories of the Institute of Geosciences of the University of Brasília and the Institute of Geosciences of the University of São Paulo for the assistance with the production of the thin sections. We are indebted to Ricardo Pinto (UnB) and André Pinheiro (UERJ) for suggestions on an earlier draft of this manuscript. The senior author thanks CAPES (grant number: 1537024) for the financial support. The silhouettes used in Figures 3 and 5 are courtesy of http://phylopic.org/. RMS thanks CNPq for the grant (401784/2010-0) which, in part, supported this research. Finally, we are grateful to two anonymous reviewers whose valuable comments improved and earlier draft of this paper.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Conselho Nacional de Desenvolvimento Científico e Tecnológico [401784/2010-0] and CAPES [1537024].