title: Reconsidering the Avian Nature of the Oviraptorosaur Brain (Dinosauria: Theropoda).
abstract: The high degree of encephalization characterizing modern birds is the product of a long evolutionary history, our understanding of which is still largely in its infancy. Here we provide a redescription of the endocranial space of the oviraptorosaurian dinosaur Conchoraptor gracilis with the goal of assessing the hypothesis that it shares uniquely derived endocranial characters with crown-group avians. The existence of such features has implications for the transformational history of avian neuroanatomy and suggests that the oviraptorosaur radiation is a product of the immediate stem lineage of birds-after the divergence of Archaeopteryx lithographica. Results derived from an expanded comparative sample indicate that the strong endocranial similarity between Conchoraptor and modern birds largely reflects shared conservation of plesiomorphic features. The few characters that are maintained as being uniquely expressed in these two taxa are more likely products of convergence than homology but still indicate that the oviraptorosaur endocranial cavity has much to teach us about the complex history of avian brain evolution.
authors.affiliation: Stony Brook University, Department of Anatomical Sciences, Stony Brook, New York, United States of America; American Museum of Natural History, Division of Paleontology, Central Park West at 79th Street, New York, New York, United States of America.
authors.forename: Amy M
authors.initials: AM
authors.lastname: Balanoff
authors.affiliation: New York Institute of Technology, College of Osteopathic Medicine, Department of Anatomy, Northern Boulevard, Old Westbury, New York, United States of America; American Museum of Natural History, Division of Paleontology, Central Park West at 79th Street, New York, New York, United States of America.
authors.forename: G S
authors.initials: GS
authors.lastname: Bever
authors.affiliation: American Museum of Natural History, Division of Paleontology, Central Park West at 79th Street, New York, New York, United States of America.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Norell
mesh_terms: D000818:Animals; D005075:Biological Evolution; D001717:Birds / Q000033:anatomy & histology*; D001921:Brain / Q000033:anatomy & histology; D025061:Dinosaurs / Q000033:anatomy & histology*; D005580:Fossils / Q000033:anatomy & histology; D008953:Models, Anatomic; D010802:Phylogeny; D012886:Skull / Q000033:anatomy & histology*; D013045:Species Specificity