MEANING: Lovebird dragon
PERIOD: Early Cretaceous
CONTINENT: Asia
Yuanyanglong is a basal oviraptorosaur with long enigmatic legs. It seems to have had a wading lifestyle, but its short snout does not support an aquatic diet. Another theory is that Yuanyanglong may have been specialized for running, but the structure of its hips are less than ideal. Associated gastroliths suggest it may have had an herbivorous or omnivorous diet.
Abstract from paper: A new oviraptorosaur, Yuanyanglong bainian gen. et sp. nov. is described based on two specimens recovered from the Lower Cretaceous Miaogou Formation of the Maortu locality in Chilantai, Inner Mongolia, China. This new species is intermediate in morphology between the earliest-diverging and late-diverging oviraptorosaurs, and our phylogenetic analysis supports it as a sister taxon to the clade formed by Avimimidae and Caenagathoidea. Notably, this new early-diverging oviraptorosaur has an ilium with an extremely short postacetabular process and hindlimbs with proportionally elongate and fused lower segments, a character combination unknown among other oviraptorosaurs but common in wading birds, suggesting a potential ecology involving wading. Preserved gastroliths similar to Caudipteryx suggest a gastric mill function in our new species, and our preliminary observations indicate potential discrepancies in the digestion mode of early- and late-diverging oviraptorosaurs.
Yuanyanglong is from the Cretaceous. The Cretaceous is a geological period that lasted from about 145 to 66 million years ago. It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of the entire Phanerozoic. The name is derived from the Latin creta, "chalk", which is abundant in the latter half of the period.
The Cretaceous was a period with a relatively warm climate, resulting in high eustatic sea levels that created numerous shallow inland seas. These oceans and seas were populated with now-extinct flora and fauna, while dinosaurs continued to dominate on land. The world was ice free, and forests extended to the poles. During this time, new groups of mammals and birds appeared. During the Early Cretaceous, flowering plants appeared and began to rapidly diversify, becoming the dominant group of plants across the Earth by the end of the Cretaceous, coincident with the decline and extinction of previously widespread gymnosperm groups.
The Cretaceous (along with the Mesozoic) ended with the Cretaceous–Paleogene extinction event, a large mass extinction in which many groups, including non-avian dinosaurs, pterosaurs, and large marine reptiles, died out. The end of the Cretaceous is defined by the abrupt Cretaceous–Paleogene boundary (K–Pg boundary), a geologic signature associated with the mass extinction that lies between the Mesozoic and Cenozoic Eras.
Yuanyanglong is an oviraptorosaur. Oviraptorosauria is a group of feathered theropod dinosaurs from the Cretaceous Period of what are now Asia and North America. They are known for their short, beaked, parrot-like skulls and bony crests that many had atop the head. They ranged in size from the turkey-sized Caudipteryx, to the 8-meter-long, 1.4-ton Gigantoraptor.
Oviraptorosaurs are closely related to birds. They had shortened beaklike jaws, and few or no teeth. The long hands typically had three long fingers each. Their tails are very short compared to other maniraptorans, and show evidence of fused vertebrae, which imply the presence of a fan of feathers. Fossilized remains have been found with impressions of well developed feathers, most notably on the wings and tail, suggesting that they functioned at least partially for display.
A number of oviraptorid specimens have been discovered in a nesting position similar to that of modern birds. The arms of these specimens are positioned in such a way that they could perfectly cover their eggs if they had small wings and a substantial covering of feathers.