Just out | Dinosaur eggshells from the Santonian Milk River Formation of Alberta, Canada @ Cretaceous Research

Just out @ Cretaceous Research


The North American fossil record of dinosaur eggshells for the Cretaceous is primarily restricted to formations of the middle (Albian–Cenomanian) and uppermost (Campanian–Maastrichtian) stages, with a large gap in the record for intermediate stages. Here we describe a dinosaur eggshell assemblage from a formation that represents an intermediate and poorly fossiliferous stage of the Upper Cretaceous, the Santonian Milk River Formation of southern Alberta, Canada. The Milk River eggshell assemblage contains five eggshell taxa: Continuoolithus, Porituberoolithus, Prismatoolithus, Spheroolithus, and Triprismatoolithus. These ootaxa are most similar to those reported from younger Campanian–Maastrichtian formations of the northern Western Interior than they are to ootaxa reported from older middle Cretaceous formations (i.e., predominantly Macroelongatoolithus). Characteristics of the Milk River ootaxa indicate that they are ascribable to at least one ornithopod and four small theropod species. The taxonomic affinity of the eggshell assemblage is consistent with the dinosaur fauna known based on isolated teeth and fragmentary skeletal remains from the formation, although most ornithischians and large theropods are not represented by eggshell. Relative to the Milk River Formation eggshell, similar oospecies occurring in younger Cretaceous deposits tend to be somewhat thicker, which may reflect an increase in body size of various dinosaur lineages during the Late Cretaceous.

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Lurdes Fonseca

Assistant Professor and Researcher at University of Lisbon
Sociologist (PhD), Paleontologist (Researcher in Micropaleontology), Majors in Sociology and Biology, Minor in Geology. Main interests in Paleontology: Microfossils, Molecular fossils, Paleobiology and Paleoecology. (read more about me)