Changmiania liaoningensis A New Basal Ornithopod from Liaoning Province

A new species of basal ornithopod dinosaur has been named and described from Liaoning Province in north-eastern China.  The dinosaur has been named Changmiania liaoningensis which translates from the Chinese as “eternal sleeper from Liaoning”.  The researchers which include Pascal Godefroit of the Royal Belgian Institute of Natural Sciences and Paul-Emile Dieudonné (Universidad Nacional de Río Negro, Argentina), in collaboration with colleagues from Jilin University and Shenyang Normal University (China), postulate that Changmiania lived in burrows.

The Holotype of Changmiania liaoningensis (PMOL AD00114) and a Life Reconstruction

The perfectly preserved holotype fossil of Changmiania liaoningensis with a life reconstruction.  The very nearly intact, articulated specimens suggest that the dinosaurs were entombed in their burrows during a volcanic eruption.

Picture Credit: Carine Ciselet

From the Lujiatun Beds of the Yixian Formation

The pair of beautifully preserved fossils, like so many vertebrate fossils from this part of the world were acquired from farmers.  Many locals supplement their incomes by finding and excavating specimens.  Whilst welcoming the opportunity to be able to study the material, palaeontologists are often frustrated by the lack of information available to them pertaining to the fossil’s location and how it was preserved (taphonomy).  However, it is thought that the fossils herald from the Lujiatun Beds (Yixian Formation) of western Liaoning Province.  These three-dimensional fossils were formed when these dinosaurs were entombed in pyroclastic material created by a volcanic eruption.  Numerous dinosaurs are known from the Lujiatun Beds including the dromaeosaurid Graciliraptor (G. lujiatunensis), the troodontid Mei long, the small tyrannosauroid Dilong paradoxus along with psittacosaurs, neoceratopsians and the ornithopod Jeholosaurus (J. shanyuensis).

Scientists have been able to accurately date the volcanic ash layer to approximately 123 million years ago, which means this diverse dinosaur biota lived during the early Aptian faunal stage of the Early Cretaceous.   The hot, volcanic debris that covered these two dinosaurs may have perfectly preserved most of the skeleton but any evidence of an integumentary covering such as feathers was destroyed as these animals met their fate whilst fast asleep in their burrows.  The resting dinosaurs having been caught up and consumed in a violent pyroclastic flow is the scenario tentatively proposed by the research team in the scientific paper published in PeerJ.

The Two Fossils of Changmiania liaoningensis

The holotype fossil (A) and a close view of the anterior portion of the holotype (B), with a second referred specimen of Changmiania liaoningensis (C).

Picture Credit: Yang et al (PeerJ)

A Basal Ornithopod

The little dinosaur measured approximately 1.2 metres long, the tail representing fifty percent of the animal’s total body length.  The extremely short neck, consisting of just six cervical vertebrae, the robust forelimbs and stocky shoulder blades suggest that this dinosaur might have dug burrows.  This idea is supported by the position of the fossil specimens and the morphology of the front of the skull, which may have assisted with shovelling dirt aside.  The long hindlimbs and tail indicate that Changmiania was a fast runner, able to avoid trouble whilst away from its underground den.

This is not the first time fossorial behaviour has been inferred for a dinosaur.  For example, in 2007 Everything Dinosaur wrote a short post about another potential burrowing ornithischian, another basal ornithopod that was named Oryctodromeus cubicularis, remains of which come from the sandstones of the Blackleaf Formation of Montana (USA): A Burrowing Dinosaur from Montana.

Changmiania lived at least 10 million years earlier than O. cubicularis.  A phylogenetic analysis places Changmiania liaoningensis as the most basal ornithopod dinosaur known to science.

The scientific paper: “A new basal ornithopod dinosaur from the Lower Cretaceous of China” by Yuqing Yang, Wenhao Wu, Paul-Emile Dieudonné and Pascal Godefroit​ published in PeerJ.

Sinankylosaurus zhuchengensis – Late Cretaceous Chinese Ankylosaur

Chinese scientists have described a new species of armoured dinosaur based on a single fossilised bone found at a dig site in the city of Zhucheng in Shandong Province (eastern China).  The fossil, a right ilium, has been identified as typical of the Ankylosauria clade and represents the first evidence found to date of ankylosaurs being present in the Late Cretaceous of that part of eastern China.  The dinosaur has been appropriately named Sinankylosaurus zhuchengensis which translates as “Chinese Ankylosaurus from Zhucheng”.

The Holotype Fossilised Right Ilium (Sinankylosaurus zhuchengensis)

The fossil ilium bone (holotype specimen) of Sinankylosaurus.  Sinankylosaurus ilium in (a) ventral and (b) dorsal views.  Scale bar = 10 cm.

Picture Credit: China Geological Bulletin

A Significant Hip Bone

The ilium is a broad, plate-like bone located at the top of the hip girdle.  Its shape and size varies considerably depending on the dinosaur genus.  These bones and the placement of the hips can be very helpful to palaeontologists when it comes to identifying different members of the Dinosauria.  For example, most theropods have narrow hips so the distance between the left and right ilia (plural for ilium), is relatively short.  However, there are exceptions, the mainly herbivorous theropods the therizinosaurids have much wider hips.  Numerous sauropods and all thyreophorans (armoured dinosaurs), have very wide hips in relation to their body proportions.  In armoured dinosaurs the distance between the left and right ilia is substantial and in Cretaceous ankylosaurs this bone is very distinctive as it exhibits lateral flaring, providing anchor points for large muscles.

The configuration of the ilium in association with the other hip bones, the ischium and pubis, led to the establishment of two main dinosaur Orders – Saurischia and Ornithischia as proposed by the British palaeontologist Harry Govier Seeley in 1887.  These three bones form the “hip socket” into which the head of the femur (thigh bone) is located.

Classifying Dinosaurs Based on Hip Structure

Classifying dinosaurs by the shape of their hip bones.  The configuration and orientation of the hip bones led to the establishment to two main groups of dinosaurs in the 19th Century.

Picture Credit: Everything Dinosaur

From the Xingezhuang Formation

The ilium was found about a decade ago.  It comes from the Xingezhuang Formation of the Upper Cretaceous Wangshi Group.  The strata have proved difficult to date but most palaeontologists suggest that this formation is between 77 to 73 million years old (middle to late Campanian faunal stage).  With so very little fossil material to go on, the scientists have used the roughly contemporaneous ankylosaurid Pinacosaurus (P. grangeri) which heralds from the Djadokhta Formation of Mongolia, as a reference and to permit a life reconstruction of an ankylosaurid to be used in media releases.

A Life Reconstruction of Pinacosaurus – Sinankylosaurus May Have Been Similar

Pinacosaurus life reconstruction.  Sinankylosaurus zhuchengensis may have been similar.

Picture Credit: Zhao Chuang (PNSO)

Sinankylosaurus is estimated to have measured around 5 metres in length and it may have weighed around 2 tonnes.

East Meets West

The discovery of a new dinosaur species adds to the diversity of dinosaurs associated with the Upper Cretaceous deposits of the Wangshi Group and also demonstrates the similarity between the dinosaurian faunas of eastern Asia and western North America in the Late Cretaceous.

For example, dinosaur fossils from the Xingezhuang Formation include hadrosaurs such as Shantungosaurus, ceratopsids such as Sinoceratops, tyrannosaurs and now an ankylosaurid.  This biota is similar to the dinosaur fauna associated with Campanian-aged deposits found in southern Canada and the USA.