Wulagasaurus
Encyclopedia
Wulagasaurus is a genus
of hadrosaurine
hadrosaurid
dinosaur
(flat-headed duckbilled dinosaur) from the Late Cretaceous
of Heilongjiang
, China
. Its remains were found in a bonebed in the latest Maastrichtian
-age Yuliangze Formation
, dated to 65.5 million years ago. This bonebed is otherwise dominated by fossils of the lambeosaurine
hadrosaurid (crested duckbill) Sahaliyania
. Wulagasaurus was named by Pascal Godefroit and colleagues in 2008. Only partial remains are known at this time. It is one of several hadrosaurids from the Amur River region named since 2000. The type
and only species to date is W. dongi, named in honor of Chinese paleontologist Dong Zhiming
.
Wulagasaurus is based on
GMH W184, a partial dentary (toothbearing bone of the lower jaw). Godefroit and colleagues assigned additional remains from the bonebed to their new genus, including three braincases, a cheekbone
, two maxilla
e (the toothbearing bone of the upper jaw), another dentary, two shoulder blades
, two sternal
elements, two upper arm
bones, and an ischium. It can be distinguished
from other hadrosaurids by its slender dentary and the unique form of its upper arm, which had distinctive articulations and placements for muscle attachments. Godefroit and colleagues performed a phylogenetic analysis
that suggests Wulagasaurus was the most basal
hadrosaurine known, and interpreted this as evidence that hadrosaurines and hadrosaurids in general originated in Asia. As a hadrosaurid, Wulagasaurus would have been an herbivore
.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of hadrosaurine
Hadrosaurinae
Saurolophinae is a subfamily of hadrosaurid dinosaurs. Members of the subfamily derive from the Late Cretaceous of Antarctica, Argentina, Canada , China, Kazakhstan, Mexico, Russia, the United States and...
hadrosaurid
Hadrosaurid
Hadrosaurids or duck-billed dinosaurs are members of the family Hadrosauridae, and include ornithopods such as Edmontosaurus and Parasaurolophus. They were common herbivores in the Upper Cretaceous Period of what are now Asia, Europe and North America. They are descendants of the Upper...
dinosaur
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...
(flat-headed duckbilled dinosaur) from the Late Cretaceous
Late Cretaceous
The Late Cretaceous is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...
of Heilongjiang
Heilongjiang
For the river known in Mandarin as Heilong Jiang, see Amur River' is a province of the People's Republic of China located in the northeastern part of the country. "Heilongjiang" literally means Black Dragon River, which is the Chinese name for the Amur. The one-character abbreviation is 黑...
, China
People's Republic of China
China , officially the People's Republic of China , is the most populous country in the world, with over 1.3 billion citizens. Located in East Asia, the country covers approximately 9.6 million square kilometres...
. Its remains were found in a bonebed in the latest Maastrichtian
Maastrichtian
The Maastrichtian is, in the ICS' geologic timescale, the latest age or upper stage of the Late Cretaceous epoch or Upper Cretaceous series, the Cretaceous period or system, and of the Mesozoic era or erathem. It spanned from 70.6 ± 0.6 Ma to 65.5 ± 0.3 Ma...
-age Yuliangze Formation
Yuliangze Formation
The Yuliangze Formation is a geological formation in Heilongjiang, China whose strata date back to the Late Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation.-Vertebrate paleofauna:...
, dated to 65.5 million years ago. This bonebed is otherwise dominated by fossils of the lambeosaurine
Lambeosaurinae
Lambeosaurinae is a group of crested hadrosaurid dinosaurs.-Classification:Lambeosaurines have been split into Parasaurolophini and Corythosaurini . Corythosaurini and Parasaurolophini as terms entered the formal literature in Evans and Reisz's 2007 redescription of Lambeosaurus magnicristatus...
hadrosaurid (crested duckbill) Sahaliyania
Sahaliyania
Sahaliyania is a genus of lambeosaurine hadrosaurid dinosaur from the Late Cretaceous of Heilongjiang, China...
. Wulagasaurus was named by Pascal Godefroit and colleagues in 2008. Only partial remains are known at this time. It is one of several hadrosaurids from the Amur River region named since 2000. The type
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
and only species to date is W. dongi, named in honor of Chinese paleontologist Dong Zhiming
Dong Zhiming
Dong Zhiming , from the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing, is one of China's leading paleontologists. He began working at the IVPP in 1962, learning from Yang Zhongjian who was director at the time...
.
Wulagasaurus is based on
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
GMH W184, a partial dentary (toothbearing bone of the lower jaw). Godefroit and colleagues assigned additional remains from the bonebed to their new genus, including three braincases, a cheekbone
Jugal
The jugal is a skull bone found in most reptiles, amphibians, and birds. In mammals, the jugal is often called the malar or Zygomatic. It is connected to the quadratojugal and maxilla, as well as other bones, which may vary by species....
, two maxilla
Maxilla
The maxilla is a fusion of two bones along the palatal fissure that form the upper jaw. This is similar to the mandible , which is also a fusion of two halves at the mental symphysis. Sometimes The maxilla (plural: maxillae) is a fusion of two bones along the palatal fissure that form the upper...
e (the toothbearing bone of the upper jaw), another dentary, two shoulder blades
Scapula
In anatomy, the scapula , omo, or shoulder blade, is the bone that connects the humerus with the clavicle ....
, two sternal
Sternum
The sternum or breastbone is a long flat bony plate shaped like a capital "T" located anteriorly to the heart in the center of the thorax...
elements, two upper arm
Humerus
The humerus is a long bone in the arm or forelimb that runs from the shoulder to the elbow....
bones, and an ischium. It can be distinguished
Autapomorphy
In cladistics, an autapomorphy is a distinctive anatomical feature, known as a derived trait, that is unique to a given terminal group. That is, it is found only in one member of a clade, but not found in any others or outgroup taxa, not even those most closely related to the group...
from other hadrosaurids by its slender dentary and the unique form of its upper arm, which had distinctive articulations and placements for muscle attachments. Godefroit and colleagues performed a phylogenetic analysis
Cladistics
Cladistics is a method of classifying species of organisms into groups called clades, which consist of an ancestor organism and all its descendants . For example, birds, dinosaurs, crocodiles, and all descendants of their most recent common ancestor form a clade...
that suggests Wulagasaurus was the most basal
Basal (phylogenetics)
In phylogenetics, a basal clade is the earliest clade to branch in a larger clade; it appears at the base of a cladogram.A basal group forms an outgroup to the rest of the clade, such as in the following example:...
hadrosaurine known, and interpreted this as evidence that hadrosaurines and hadrosaurids in general originated in Asia. As a hadrosaurid, Wulagasaurus would have been an herbivore
Herbivore
Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...
.