2008/04/14 by Darla K. Zelenitsky, François Therrien · 3 citations
Earth and Planetary Sciences · #Paleontology and Evolutionary Biology #Paleontology and Stratigraphy of Fossils #Evolution and Paleontology Studies
paper · doi:10.1111/j.1475-4983.2008.00770.x
openalex publication_date 2008/04/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/05/21
Abstract: A phylogenetic analysis of reproductive and oological (egg) traits of theropod taxa allows determination of the sequence in which these traits evolved in Theropoda. Our results indicate that several avian reproductive traits, such as adults sitting on eggs, asymmetrical eggs, unornamented eggshell surface, and complex eggshell ultrastructure, were already present in non‐avian maniraptorans, and could have evolved in more basal theropods. In addition, non‐avian maniraptorans laid two eggs at a time and orientated their eggs subvertically or subhorizontally in their nests, features not retained by neornithine birds. Based on our cladistic analysis it is also possible to infer the phylogenetic affinity of ootaxa of unknown parentage: Protoceratopsidovum was laid by a maniraptoran more derived than oviraptorids, and Parvoolithus probably belonged to a Cretaceous bird. Finally, our analysis reveals that many of the high‐level categories of egg parataxonomy (morphotypes and basic types) are unnatural groupings (i.e. non‐monophyletic). We recommend that these high‐level categories be abandoned because oofamilies are sufficient to categorize egg taxa.