Epipophyses
The epipophyses are bony projections of the cervical vertebrae found in dinosaurs and some fossil basal birds.[1] These paired processes sit above the postzygapophyses on the rear of the vertebral neural arch.[1] Their morphology is variable and ranges from small, simple, hill-like elevations to large, complex, winglike projections.[1] Epipophyses provided large attachment areas for several neck muscles; large epipophyses are therefore indicative of a strong neck musculature.[1]
The presence of epipophyses is a synapomorphy (distinguishing feature) of the group Dinosauria.[1] Epipophyses were present in the basal-most dinosaurs, but absent in closely related ancestors of this group like Marasuchus and Silesaurus.[1] They were typical for most dinosaur lineages; however, they became lost in several derived theropod lineages in the wake of an increasingly S-shaped curvature of the neck.[1][2]
