Micromorphology of Paleosols of the Marília Formation and their Significance in the Paleoenvironmental Evolution of the Bauru Basin, Upper Cretaceous, Southeastern Brazil

A new crocodyliform from the Upper Cretaceous (Campanian-Maastrichtian) Presidente Prudente Formation of the Bauru Group is described based on two almost complete skulls and mandibles. The material comes from the "Tartaruguito" site, situated at an old railroad between the cities of Pirapozinho and Presidente Prudente, state of São Paulo, Brazil. The new species, Pepesuchus deiseae gen. et sp. nov., is classified in the clade Peirosauridae on the basis of three synapomorphies: the presence of five premaxillary teeth, the anterior two premaxillary alveoli nearly confluent, and the oval cross-section of the jugal along the lower temporal bar. The new taxon increases the outstanding crocodyliform diversity of the Bauru Group, particularly of the Peirosauridae, which might turn out to be one of the most representative clades of gondwanan mesoeucrocodylians.

Download Full-text

NEW RECORDS OF FOSSIL VERTEBRATES FROM THE UPPER CRETACEOUS ADAMANTINA FORMATION (BAURU GROUP), SOUTHEASTERN BRAZIL

Revista do Instituto Geológico ◽

10.5935/0100-929x.20140008 ◽

2014 ◽

Vol 35 (2) ◽

Cited By ~ 1

Author(s):

Caio Fabricio Cezar Geroto ◽

Reinaldo José Bertini

Keyword(s):

Upper Cretaceous ◽

New Records ◽

Southeastern Brazil ◽

Bauru Group

Download Full-text

Dental replacement in Mesozoic birds: evidence from newly discovered Brazilian enantiornithines

Scientific Reports ◽

10.1038/s41598-021-98335-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Yun-Hsin Wu ◽

Luis M. Chiappe ◽

David J. Bottjer ◽

William Nava ◽

Agustín G. Martinelli

Keyword(s):

High Resolution ◽

Upper Cretaceous ◽

Control Mechanism ◽

Early Stage ◽

Southeastern Brazil ◽

3D Reconstructions ◽

3D Data ◽

Tooth Roots ◽

Replacement Pattern ◽

Deep Homology

AbstractPolyphyodonty—multiple tooth generations—in Mesozoic birds has been confirmed since the nineteenth century. Their dental cycle had been assessed through sparse data from tooth roots revealed through broken jawbones and disattached teeth. However, detailed descriptions of their tooth cycling are lacking, and the specifics of their replacement patterns remain largely unknown. Here we present unprecedented µCT data from three enantiornithine specimens from the Upper Cretaceous of southeastern Brazil. The high resolution µCT data show an alternating dental replacement pattern in the premaxillae, consistent with the widespread pattern amongst extinct and extant reptiles. The dentary also reveals dental replacement at different stages. These results strongly suggest that an alternating pattern was typical of enantiornithine birds. µCT data show that new teeth start lingually within the alveoli, resorb roots of functional teeth and migrate labially into their pulp cavities at an early stage, similar to modern crocodilians. Our results imply that the control mechanism for tooth cycling is conserved during the transition between non-avian reptiles and birds. These first 3D reconstructions of enantiornithine dental replacement demonstrate that 3D data are essential to understand the evolution and deep homology of archosaurian tooth cycling.

Download Full-text