Article

 

Tiny, ornamented eggs and eggshell from the Upper Cretaceous of Utah represent a new ootaxon with theropod affinities Público Deposited

https://scholar.colorado.edu/concern/articles/76537272f
Abstract
  • A new Cretaceous ootaxon (eggshell type) from the Kaiparowits Formation of Grand Staircase-Escalante National Monument is among a growing number of very small eggs described from the Mesozoic. Analyses of two partial eggs (~ 17.7 mm in diameter) and 29 eggshell fragments reveal that this new ootaxon exhibits nodose ornamentation with distinctive branching pore canals that open atop the nodes. Its two-layered microstructure consists of a mammillary layer and a continuous layer with rugged grain boundaries between calcite grains. Although the exact identity of the egg producer is unknown, the eggshell microstructure and small size is consistent with a small-bodied avian or non-avian theropod. The specific combination of small egg size, branching pores, two-layered microstructure, and dispersituberculate ornamentation preserved in this new ootaxon is unique among theropod eggs. This underscores that both eggshell and skeletal fossils of Cretaceous theropods can display a mosaic of transitional morphological and behavioural features characteristic of both avian and non-avian taxa. As such, this new ootaxon increases the diversity of Cretaceous eggs and informs our understanding of the evolution of theropod eggshell microstructure and morphology.

     

Creator
Date Issued
  • 2021
Academic Affiliation
Journal Title
Journal Volume
  • 11
Última modificación
  • 2022-08-12
Resource Type
Declaración de derechos
DOI
ISSN
  • 2045-2322
Language
License

Relaciones

Elementos