A new genus and species of early-diverging oviraptorosaurian dinosaur has been identified from two specimens found in Inner Mongolia, China.
Life reconstruction of Yuanyanglong bainian. Image credit: Sci.News / Ddinodan.
“Oviraptorosauria is a group of specialized pennaraptoran theropods known primarily from an abundant Asian and North American Cretaceous fossil record,” said Dr. Xing Xu, a paleontologist from the Institute of Vertebrate Paleontology and Paleoanthropology at Chinese Academy of Sciences and the Centre for Vertebrate Evolutionary Biology at Yunnan University, and colleagues.
“In recent years, a series of new discoveries have enriched our knowledge of their diversity, behaviors, ontogeny and reproductive biology.”
“With over 40 genera named, unquestionable oviraptorosaurs include the earliest-diverging species such as Incisivosaurus and Caudipterygidae from northeastern China, and highly specialized edentulous species such as Avimimus from the Gobi Desert, Oviraptoridae from eastern Asia and Caenagnathidae from Asia and North America, with most known species being from the Late Cretaceous.”
The new oviraptorosaur species lived in what is now China during the Early Cretaceous, some 110 million years ago.
Named Yuanyanglong bainian, it displays a unique combination of morphological features distinguishing it from all previously known oviraptorosaurs.
“Yuanyanglong bainian can be identified as an oviraptorosaur based on the short and deep skull as well as several pelvic characters (i.e. a midway-placed triangular obturator process on the ischium and a nearly ventrally-directed long pubis),” the paleontologists said.
“Among oviraptorosaurs, however, Yuanyanglong bainian shows unique combination of features not shared by previously known clades, such as the hooked posterior process of the pubic boot which is longer than the rounded anterior process.”
Two articulated skeletons of Yuanyanglong bainian, including a partial skull and some postcranial bones, were collected in the summer of 2021 from the Maortu locality of the Miaogou Formation in Chilantai, western Inner Mongolia, China.
The discovery offers the first Early Cretaceous oviraptorosaur record near the Gobi Desert, and provides additional insights into the biology and ecology of early-diverging oviraptorosaurs.
“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,” the researchers said.
“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.”
The team’s findings were published in the journal Cretaceous Research.
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Mingze Hao et al. A new oviraptorosaur from the Lower Cretaceous Miaogou Formation of western Inner Mongolia, China. Cretaceous Research, published online October 24, 2024; doi: 10.1016/j.cretres.2024.106023
