Shuangmiaosaurus
Encyclopedia
Shuangmiaosaurus is a genus
of herbivorous ornithischian dinosaur
which lived during the late Albian
age of the Early Cretaceous Period, about 100 million years ago. It was an iguanodont
euornithopod which lived in China
.
The type species
, Shuangmiaosaurus gilmorei, was named and described by You Hailu, Ji Qiang Li Jinglu and Li Yinxian in 2003. The generic name refers to the village of Shuangmiao
in Beipiao
in Liaoning
Province, the site of the discovery. The specific name honours the American paleontologist Charles Whitney Gilmore.
The holotype
, specimen LPM 0165, was found in the Sunjiawan Formation
, originally seen as dating to the Late Cretaceous
(Cenomanian
to Turonian
) but today considered to have been somewhat older. It consists of a partial left upper jaw and lower jaw, including the maxilla
, part of the praemaxilla, elements of the lacrymal and the dentary.
Shuangmiaosaurus was a rather large euornithopod. In 2010 Gregory S. Paul
estimated its length at 7.5 metres, its weight at 2.5 tonnes.
Shuangmiaosaurus was originally considered a basal
member of the Hadrosauroidea
, one closely related to the Hadrosauridae. Subsequent authors, including David B. Norman
of Cambridge University, consider it a more basal member of the Iguanodontia outside of the Hadrosauroidea.
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 herbivorous ornithischian 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...
which lived during the late Albian
Albian
The Albian is both an age of the geologic timescale and a stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early/Lower Cretaceous epoch/series. Its approximate time range is 112.0 ± 1.0 Ma to 99.6 ± 0.9 Ma...
age of the Early Cretaceous Period, about 100 million years ago. It was an iguanodont
Iguanodont
Iguanodonts were herbivorous dinosaurs that lived from the mid-Jurassic to Late Cretaceous. Some members include Camptosaurus, Callovosaurus, Iguanodon, Ouranosaurus, and the hadrosaurids or "duck-billed dinosaurs". Iguanodonts were one of the first groups of dinosaurs to be found...
euornithopod which lived in China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
.
The type species
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...
, Shuangmiaosaurus gilmorei, was named and described by You Hailu, Ji Qiang Li Jinglu and Li Yinxian in 2003. The generic name refers to the village of Shuangmiao
Shuangmiao
Shuangmiao is a township-level division situated in Bozhou, Anhui, China....
in Beipiao
Beipiao
Beipiao is a city in Chaoyang prefecture, Liaoning province, in Northeast China. It has a population of 202,807. The main industry in the area is coal mining. With vertical shafts of almost 1000m, these are some of the deepest coal mines in China. The coal produced is used for coking...
in Liaoning
Liaoning
' is a province of the People's Republic of China, located in the northeast of the country. Its one-character abbreviation is "辽" , a name taken from the Liao River that flows through the province. "Níng" means "peace"...
Province, the site of the discovery. The specific name honours the American paleontologist Charles Whitney Gilmore.
The holotype
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...
, specimen LPM 0165, was found in the Sunjiawan Formation
Sunjiawan Formation
The Sunjiawan Formation is a geological formation in Liaoning, China whose strata date back to the Early Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation.-Vertebrate paleofauna:...
, originally seen as dating to 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...
(Cenomanian
Cenomanian
The Cenomanian is, in the ICS' geological timescale the oldest or earliest age of the Late Cretaceous epoch or the lowest stage of the Upper Cretaceous series. An age is a unit of geochronology: it is a unit of time; the stage is a unit in the stratigraphic column deposited during the corresponding...
to Turonian
Turonian
The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous epoch, or a stage in the Upper Cretaceous series. It spans the time between 93.5 ± 0.8 Ma and 89.3 ± 1 Ma...
) but today considered to have been somewhat older. It consists of a partial left upper jaw and lower jaw, including the 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...
, part of the praemaxilla, elements of the lacrymal and the dentary.
Shuangmiaosaurus was a rather large euornithopod. In 2010 Gregory S. Paul
Gregory S. Paul
Gregory Scott Paul is a freelance researcher, author and illustrator who works in paleontology, and more recently has examined sociology and theology. He is best known for his work and research on theropod dinosaurs and his detailed illustrations, both live and skeletal...
estimated its length at 7.5 metres, its weight at 2.5 tonnes.
Shuangmiaosaurus was originally considered a 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:...
member of the Hadrosauroidea
Hadrosauroidea
Hadrosauroidea is a clade or superfamily of ornithischian dinosaurs that includes the "duck-billed" dinosaurs, or hadrosaurids, and their close relatives. Many primitive hadrosauroids, such as the sail-backed Ouranosaurus, have traditionally been included in a paraphyletic "Iguanodontidae"...
, one closely related to the Hadrosauridae. Subsequent authors, including David B. Norman
David B. Norman
David Bruce Norman is a British paleontologist, currently Director of the Sedgwick Museum, Cambridge University. He is a fellow at Christ's College, Cambridge where he teaches geology in the Natural Sciences tripos. He is a member of the Palaeontological Association. He has studied Iguanodon...
of Cambridge University, consider it a more basal member of the Iguanodontia outside of the Hadrosauroidea.