Gigantspinosaurus
Encyclopedia
Gigantspinosaurus is a genus
of herbivorous ornithischian dinosaur
from the Late Jurassic
. It was a stegosaur found in Sichuan
, China
.
The first fossil was found in 1985 by Ouyang Hui at Pengtang near Jinquan and was reported upon in 1986 by Gao Ruiqi and colleagues, mistaking it for a specimen of Tuojiangosaurus
. The type species
, Gigantspinosaurus sichuanensis, was described and named by Ouyang in 1992 in an abstract of a lecture. The generic name is derived from Latin
gigas or giganteus, "enormous", and spina, "spine", in reference to the gigantic shoulder spines. The specific name refers to Sichuan.
The name was generally considered a nomen nudum
in the West, until in 2006 it was disclosed that the abstract contained a sufficient description. Despite its uncertain nomenclatural status, images of Gigantspinosaurus had appeared in several sources. Public awareness of this animal was increased in early 2006 when Tracy Ford, considering it a validly established taxon, published a short article on reconstructing it. Ford suggested that earlier reconstructions of Gigantspinosaurus attached the shoulder spines upside-down, and his new reconstruction shows the spine extending somewhat upwards, ending higher than the top of the animal's back. Susannah Maidment and Wei Guangbiao in 2006 concluded that G. sichuanensis was a valid taxon in their review of Late Jurassic Chinese stegosaurs, but did not redescribe it because at that time it was under study by Zigong Dinosaur Museum
staff. In fact, a Chinese redescription by Peng Guangzhao and colleagues in 2005 would predate Maidment's publication.
The holotype
, ZDM
0019, was found in layers of the Upper Shaximiao Formation of Zigong
(Sichuan province), which date to the Oxfordian. It consists of a partial skeleton of a probably subadult individual missing the skull (though the lower jaws are present), hind feet, and the tail end. Apart from skeletal elements also plates, spines and scutes have been found. At the left shoulder an impression of the skin had been preserved. The specimen is part of the collection of the Zigong Dinosaur Museum and has as a mounted restored skeleton been on display since 1996. In 2005 Peng e.a. reported a second specimen, ZDM 0156, a pelvis found at Chenjia
near Fuquan.
Gigantspinosaurus was described by Peng and colleagues as a "medium-sized stegosaur". It was estimated by Gregory S. Paul
in 2010 to have been about 4.2 metres (13.8 ft) long and 700 kilograms (1,543.2 lb) in weight. Gigantspinosaurus has a distinctive appearance with relatively small dorsal plates and greatly enlarged shoulder spines, spinae parascapulares, twice the length of the shoulder blades
on which they rested via large flat bases. The plates on the neck are small and triangular. The head must have been relatively large with thirty teeth in each lower jaw. The hips are very broad and the low neural spines of the four sacral vertebrae and the first tail vertebra have been fused into a single plate. The forelimbs are robust.
The skin impressions were described by Xing Lida and colleagues in 2008. They cover a surface of 414 square centimetres (64.2 sq in) and show rosettes with a central pentagonal or hexagonal scale surrounded by thirteen to fourteen ridged smaller square, pentagonal or hexagonal scales with a diameter of 5.7 to 9.2 mm (0.224409448818898 to 0.362204724409449 in).
A study by Maidment indicated that Gigantspinosaurus is the most basal known member of the Stegosauria
. Peng and colleagues, however, placed it in the Huayangosaurinae.
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...
from the Late Jurassic
Late Jurassic
The Late Jurassic is the third epoch of the Jurassic Period, and it spans the geologic time from 161.2 ± 4.0 to 145.5 ± 4.0 million years ago , which is preserved in Upper Jurassic strata. In European lithostratigraphy, the name "Malm" indicates rocks of Late Jurassic age...
. It was a stegosaur found in Sichuan
Sichuan
' , known formerly in the West by its postal map spellings of Szechwan or Szechuan is a province in Southwest China with its capital in Chengdu...
, 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...
.
The first fossil was found in 1985 by Ouyang Hui at Pengtang near Jinquan and was reported upon in 1986 by Gao Ruiqi and colleagues, mistaking it for a specimen of Tuojiangosaurus
Tuojiangosaurus
Tuojiangosaurus is a genus of stegosaurid dinosaur from the Late Jurassic Period, recovered from the Upper Shaximiao Formation of what is now Sichuan Province in China. Physically similar to the North American Stegosaurus, Tuojiangosaurus is the best understood of the Chinese stegosaurids...
. 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...
, Gigantspinosaurus sichuanensis, was described and named by Ouyang in 1992 in an abstract of a lecture. The generic name is derived from Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
gigas or giganteus, "enormous", and spina, "spine", in reference to the gigantic shoulder spines. The specific name refers to Sichuan.
The name was generally considered a nomen nudum
Nomen nudum
The phrase nomen nudum is a Latin term, meaning "naked name", used in taxonomy...
in the West, until in 2006 it was disclosed that the abstract contained a sufficient description. Despite its uncertain nomenclatural status, images of Gigantspinosaurus had appeared in several sources. Public awareness of this animal was increased in early 2006 when Tracy Ford, considering it a validly established taxon, published a short article on reconstructing it. Ford suggested that earlier reconstructions of Gigantspinosaurus attached the shoulder spines upside-down, and his new reconstruction shows the spine extending somewhat upwards, ending higher than the top of the animal's back. Susannah Maidment and Wei Guangbiao in 2006 concluded that G. sichuanensis was a valid taxon in their review of Late Jurassic Chinese stegosaurs, but did not redescribe it because at that time it was under study by Zigong Dinosaur Museum
Zigong Dinosaur Museum
Located near the Prefecture-level city of Zigong, China, in the smaller township of Dashanpu, is the Zigong Dinosaur Museum. The museum sits on top of a large concentration of dinosaur fossils — both in terms of quantity but also of diversity. The museum claims the largest number of dinosaur...
staff. In fact, a Chinese redescription by Peng Guangzhao and colleagues in 2005 would predate Maidment's publication.
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...
, ZDM
Zigong Dinosaur Museum
Located near the Prefecture-level city of Zigong, China, in the smaller township of Dashanpu, is the Zigong Dinosaur Museum. The museum sits on top of a large concentration of dinosaur fossils — both in terms of quantity but also of diversity. The museum claims the largest number of dinosaur...
0019, was found in layers of the Upper Shaximiao Formation of Zigong
Zigong
Zigong , ancient name Ziliujing and Gongjing, is a prefecture-level city and the third largest city in Sichuan Province, in southwest China.-Geography:...
(Sichuan province), which date to the Oxfordian. It consists of a partial skeleton of a probably subadult individual missing the skull (though the lower jaws are present), hind feet, and the tail end. Apart from skeletal elements also plates, spines and scutes have been found. At the left shoulder an impression of the skin had been preserved. The specimen is part of the collection of the Zigong Dinosaur Museum and has as a mounted restored skeleton been on display since 1996. In 2005 Peng e.a. reported a second specimen, ZDM 0156, a pelvis found at Chenjia
Chenjia
Chenjia may refer to:*Chenjia, Chongming County , Shanghai*Chenjia, Zizhong County , in Zizhong County, Sichuan*Chenjia Township , Panshan County, Liaoning...
near Fuquan.
Gigantspinosaurus was described by Peng and colleagues as a "medium-sized stegosaur". It was estimated by 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...
in 2010 to have been about 4.2 metres (13.8 ft) long and 700 kilograms (1,543.2 lb) in weight. Gigantspinosaurus has a distinctive appearance with relatively small dorsal plates and greatly enlarged shoulder spines, spinae parascapulares, twice the length of the shoulder blades
Scapula
In anatomy, the scapula , omo, or shoulder blade, is the bone that connects the humerus with the clavicle ....
on which they rested via large flat bases. The plates on the neck are small and triangular. The head must have been relatively large with thirty teeth in each lower jaw. The hips are very broad and the low neural spines of the four sacral vertebrae and the first tail vertebra have been fused into a single plate. The forelimbs are robust.
The skin impressions were described by Xing Lida and colleagues in 2008. They cover a surface of 414 square centimetres (64.2 sq in) and show rosettes with a central pentagonal or hexagonal scale surrounded by thirteen to fourteen ridged smaller square, pentagonal or hexagonal scales with a diameter of 5.7 to 9.2 mm (0.224409448818898 to 0.362204724409449 in).
A study by Maidment indicated that Gigantspinosaurus is the most basal known member of the Stegosauria
Stegosauria
Known colloquially as stegosaurs, the Stegosauria are a group of herbivorous dinosaurs of the Jurassic and Early Cretaceous Periods, being found mostly in the Northern Hemisphere, predominantly in what is now North America and China....
. Peng and colleagues, however, placed it in the Huayangosaurinae.