Reproduction Nemegtomaia

diagram showing remains , body outline of nesting specimen

the nemegtomaia specimen mpc-d 107/15 found associated nest eggs; feet placed in centre of ring of eggs, arms folded across tops of eggs on each side of body, posture similar seen in other fossils of brooding oviraptorids. collected part of nest 90 cm (35 in) wide , 100 cm (30 in) long; skeleton occupies upper 25 cm (10 in) of block, whereas remaining 20 cm (8 in) occupied broken eggs , shells. there no evidence of plant material in nest, there fragments of undetermined bones. nest not preserve complete eggs or embryos, prevents determination of size, shape, number, , arrangement of eggs in nest. probable there 2 layers of eggs below body, , there not appear have been eggs in centre of nest. eggs (seven distinct eggs have been identified) , egg fragments recovered either in lower layer of nest or under skull, neck, , limbs of specimen, , bones either rested directly on eggs or within 5 mm (0.2 in) of surfaces. skeleton directly positioned on top of shows nest not covered sand. though placement of eggs not suggest specific arrangement in nest, other oviraptorid nests show eggs arranged in pairs in 3 levels of concentric circles. eggs of mpc-d 107/15 therefore displaced during burial, or external factors, such strong winds, sandstorms, or predators. supports idea upper layer of eggs not buried, buried eggs have been less transported external factors.

eggs preserved nesting specimen

oviraptorid eggs appear have been 17 cm (6 in) long on average, , complete eggs found mpc-d 107/15 thought have been 5 to 6 cm (2 to 2.3 in) wide , 14 16 cm (5 to 6 in) long when intact. eggs identical have been found in mongolia, , have therefore been assigned oofamily (egg-taxon family) elongatoolithidae. eggshells relatively thin, between 1 and 1.2 mm (0.03 and 0.04 in), , outer surface covered ridges , nodes rise 0.3 mm (0.01 in) above shell. micro-structure of eggshells not studied, calcite has been heavily altered , re-crystallized.

the nesting specimen found in stratigraphic area indicating oviraptorids preferred nesting near streams provided soft, sandy substrate , food in environments otherwise xeric (receiving small amount of moisture). many oviraptorids have been found in brooding positions, indicating may have brooded relatively long periods, similar modern birds such ostrich, emu, , black-breasted buzzard, brood more 40 days limited supply of sustenance. nesting in desert environments can harmful adults stay in nest large parts of day, , eggs , nestlings, due heat stress. choice of nesting area may therefore have been mechanism successful incubation in extreme heat. has been suggested evolution of tail-feathers in oviraptorosaurs adaptation shading , protecting eggs in nests. second finger of ingeniine oviraptorids reduced in size compared robust first finger may explained change in function; may related presence of long wing feathers attached second finger. these wing feathers used protect eggs during nesting. when second finger began functioning feather support, ability grasp reduced, , function taken on first finger, therefore became more robust. third finger reduced in size, too, because positioned behind wing feathers in way not effective grasping.

the brooding behaviour of oviraptorids thought have been similar of birds such ostriches; here, male somali ostrich

various studies have suggested several individuals gather eggs in single nest, , arrange them protected 1 individual, possibly male. in 2010 david j. varricchio , colleagues found relatively large clutch-size of oviraptorids , troodontids similar of modern archosaurs (birds , crocodilians, closest living relatives of dinosaurs) practice polygamous mating , extensive male parental care (as seen in paleognaths such ostriches , emus). reproductive system pre-dates origin of birds , therefore ancestral condition modern birds, biparental care (where both parents participate) being later development. many oviraptorosaurs known have had pygostyles on end of tails, suggests presence of feather-fans; these have been used intraspecific communication such courtship rituals.