Yuanyanglong

{{Speciesbox

| fossil_range = Early Cretaceous, {{fossilrange|earliest=Barremian|Aptian|Albian|~Aptian–Albian}}

| image=Yuanyanglong Skeletal.svg

| image_caption=Skeletal reconstruction including the holotype (white) and referred (orange) specimens

| display_parents = 2

| genus = Yuanyanglong

| parent_authority = Hao et al., 2025

| species = bainian

| authority = Hao et al., 2025

}}

Yuanyanglong (meaning "lovebird dragon") is an extinct genus of oviraptorosaurian theropod dinosaurs from the Early Cretaceous Miaogou Formation of China. The genus contains a single species, Yuanyanglong bainian, known from two partial skeletons.{{Cite journal |last1=Hao |first1=Mingze |last2=Li |first2=Zhiyu |last3=Wang |first3=Zhili |last4=Wang |first4=Shuqiong |last5=Ma |first5=Feimin |last6=Qinggele |last7=King |first7=J. Logan |last8=Pei |first8=Rui |last9=Zhao |first9=Qi |last10=Xu |first10=Xing |date=March 2025 |title=A new oviraptorosaur from the Lower Cretaceous Miaogou Formation of western Inner Mongolia, China |url=https://linkinghub.elsevier.com/retrieve/pii/S0195667124001964 |journal=Cretaceous Research |language=en |volume=167 |at=106023 |issue= |doi=10.1016/j.cretres.2024.106023|bibcode=2025CrRes.16706023H |url-access=subscription }}

Discovery and naming

The Yuanyanglong fossil material, was discovered in 2021 in sediments of the Miaogou Formation (Maortu locality) in the Gobi Desert of Chilantai, Inner Mongolia, China. Two incomplete skeletons were found in association on the same block, which are assumed to represent the same species based on comparable anatomy and body size. The holotype specimen, PV02476-1, consists of the pelvic girdle, the right hindlimb missing the foot, the pectoral girdle, the right forelimb missing the hand, several ribs, and dorsal and caudal vertebrae. The associated referred specimen, PV02476-2, includes an incomplete poorly-preserved skull, partial hindlimb without the foot, incomplete pelvis, several dorsal vertebrae, and a partial sacrum.

In 2024, Hao et al. announced Yuanyanglong bainian as a new genus and species of early oviraptorosaurs based on these fossil remains. The generic name, Yuanyanglong, combines yuanyang (鴛鴦), the Mandarin word for "lovebirds" (the mandarin duck), a species symbolic of mating for life with the Chinese word long, meaning "dragon". This name refers to the two discovered associated individuals. The specific name, bainian (百年), is a Chinese word meaning "a hundred years", commemorating the 100th anniversary of the first named oviraptorosaur taxa, Chirostenotes and Oviraptor, in March 1924 and November 1924, respectively.{{cite journal | last1 = Gilmore | first1 = C.W. | year = 1924 | title = A new coelurid dinosaur from the Belly River Cretaceous of Alberta | journal = Canada Department of Mines Geological Survey Bulletin (Geological Series) | volume = 38 | issue = 43| pages = 1–12 }}{{cite journal|last1=Osborn|first1=H. F.|date=1924|title=Three new Theropoda, Protoceratops zone, central Mongolia|journal=American Museum Novitates|number=144|pages=1−12|hdl=2246/3223|hdl-access=free|oclc=40272928}} The final version of the article describing Yuanyanglong bainian was published the following year.

Yuanyanglong represents the first Early Cretaceous oviraptorosaur to be named from the Gobi Desert region, with other Gobi relatives coming from Late Cretaceous outcrops.

File:Yuanyanglong bainian.png]]

Classification

In their phylogenetic analyses, Hao et al. (2025) recovered Yuanyanglong as a basal member of the Oviraptorosauria, diverging after the Caudipteridae as the sister taxon to the Edentoraptora (Avimimidae [Avimimus spp.] + Caenagnathoidea). Their results are displayed in the cladogram below: