did not provide a formal definition. However, according to Mickey Mortimer, the clade can be considered valid because its describers explicitly name it as new, which satisfies ICZN Article 16.1. Paleobiology Diet The diet of oviraptorids is not fully understood. Though some appear to have been at least partially carnivorous, they were probably primarily herbivorous. Originally, oviraptorids were thought to be specialized egg raiders, based on a Mongolian find showing Oviraptor on top of a nest erroneously attributed to the ceratopsian dinosaur Protoceratops. However, discoveries in the 1990s, including Citipati specimens clearly brooding (rather than preying on) the same types of nests, and a Citipati embryo inside the same type of egg preserved in these nests, showed that the "specialized egg thief" idea was incorrect. Still, some scientists have suggested that oviraptorids may have fed on shelled food items like eggs or shellfish. However, animals specialized for eating shelled food typically have broad, crushing beaks or teeth. In contrast, the jaws of oviraptorids had thin, sharp edges probably supporting shearing beaks, ill-suited for cracking shells. Among other known animals, the beaks of oviraptorids most closely resemble those of herbivorous dicynodont synapsids, which are usually considered herbivorous. Their beaks also share similarities with the beaks of herbivorous parrots and tortoises. Evidence of partial carnivory among some oviraptorines comes from a lizard skeleton preserved in the body cavity of the type specimen of Oviraptor and two hatchling Byronosaurus skulls found in a Citipati nest. Some scientists have also suggested that some oviraptorids (especially the small-handed, weak-clawed "ingeniines") fed mainly on plant material. Reproduction Although fossilized dinosaur eggs are generally rare, oviraptorid eggs are relatively well known. Several oviraptorid nests, eggs, and embryos are known, mostly uncovered in the Gobi Desert. Some specimens of Oviraptor philoceratops, Citipati osmolskae, Nemegtomaia and cf. Machairasaurus have been found in brooding positions in association with nests. All of the nesting specimens are situated on top of egg clutches, with their limbs spread symmetrically on each side of the nest, front limbs covering the nest perimeter. This brooding posture is found today only in birds and supports a behavioral link between birds and theropod dinosaurs. Oviraptorid eggs are shaped like elongated ovals (elongatoolithid) and resemble the eggs of ratite birds (such as ostriches) in texture and shell structure. In the nest, eggs are typically found in pairs and arranged in concentric circles of up to three layers, with