Suzhousaurus
Encyclopedia
Suzhousaurus is a genus
of herbivorous therizinosauroid theropod dinosaur
from the Early Cretaceous
-age Xinminpu Group of the Yujingzi Basin, Gansu
, China
.
Suzhousaurus megatherioides was named and described by Li Daqing, Peng Cuo, You Hailu, Matthew Lamanna, Jerrald Harris, Kenneth Lacovara and Zhang Jianping in 2007. The generic name is derived from Suzhou
, the old name for Jiuquan
, the prefecture the find was made in during the late twentieth century. The specific name indicates a resemblance to Megatherium
, the giant ground sloth
.
The holotype
, FRDC-GSJB-99, was found in layers dating to the Aptian
-Albian
. It consists of a partial skeleton lacking the skull. It contains a distinctive right upper arm
that establishes it as a therizinosauroid, a right scapula
, ten dorsal vertebrae, ribs, a partial ilium
and the pubes. In 2008 another partial postcranial skeleton was described, specimen FRDC-GSJB-2004-001 found in 2004 at the same site. It contains the last three dorsal vertebrae, a sacrum
of five vertebrae, the first six tail vertebrae, the left half of a pelvis and two thighbones.
Suzhousaurus might be identical to "Nanshiungosaurus
" bohlini, an earlier named therizinosauroid found in the same formation and also known from limited remains. If so, the species name would be "Suzhousaurus bohlini". A comparison is difficult because there is little overlapping material and the holotype of "Nanshiungosaurus" bohlini is lost.
estimated the body length at six metres, the weight at 1.3 tonnes. Suzhousaurus is distinguished by a straight flat front part of the ilium and a flattened pubis
curving strongly forward forming a hollow front edge of its shaft.
that found the genus to be more derived
than Beipiaosaurus
and Falcarius
, less derived than Alxasaurus
and true therizinosaurids, and the sister taxon of Nothronychus
, forming a clade
with it.
An analysis by Lindsay Zanno in 2010 found a more derived position as the sister taxon of the Therizinosauridae
, as shown by this cladogram
:
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 therizinosauroid theropod 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 Early Cretaceous
Early Cretaceous
The Early Cretaceous or the Lower Cretaceous , is the earlier or lower of the two major divisions of the Cretaceous...
-age Xinminpu Group of the Yujingzi Basin, Gansu
Gansu
' is a province located in the northwest of the People's Republic of China.It lies between the Tibetan and Huangtu plateaus, and borders Mongolia, Inner Mongolia, and Ningxia to the north, Xinjiang and Qinghai to the west, Sichuan to the south, and Shaanxi to the east...
, 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...
.
Discovery and naming
The type speciesType 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...
Suzhousaurus megatherioides was named and described by Li Daqing, Peng Cuo, You Hailu, Matthew Lamanna, Jerrald Harris, Kenneth Lacovara and Zhang Jianping in 2007. The generic name is derived from Suzhou
Suzhou
Suzhou , previously transliterated as Su-chou, Suchow, and Soochow, is a major city located in the southeast of Jiangsu Province in Eastern China, located adjacent to Shanghai Municipality. The city is situated on the lower reaches of the Yangtze River and on the shores of Taihu Lake and is a part...
, the old name for Jiuquan
Jiuquan
- Suzhou town :The administrative center of the "prefecture-level city" of Jiuquan is the "District" of Suzhou , which occupies 3,386 square km in the eastern part of Jiuquan "prefecture-level city", and had a population of 340,000 as of 2002....
, the prefecture the find was made in during the late twentieth century. The specific name indicates a resemblance to Megatherium
Megatherium
Megatherium was a genus of elephant-sized ground sloths endemic to Central America and South America that lived from the Pliocene through Pleistocene existing approximately...
, the giant ground sloth
Ground sloth
Ground sloths are a diverse group of extinct sloths, in the mammalian superorder Xenarthra. Their most recent survivors lived in the Antilles, where it has been proposed they may have survived until 1550 CE; however, the youngest AMS radiocarbon date reported is 4190 BP, calibrated to c. 4700 BP...
.
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...
, FRDC-GSJB-99, was found in layers dating to the Aptian
Aptian
The Aptian is an age in the geologic timescale or a stage in the stratigraphic column. It is a subdivision of the Early or Lower Cretaceous epoch or series and encompasses the time from 125.0 ± 1.0 Ma to 112.0 ± 1.0 Ma , approximately...
-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...
. It consists of a partial skeleton lacking the skull. It contains a distinctive right upper arm
Humerus
The humerus is a long bone in the arm or forelimb that runs from the shoulder to the elbow....
that establishes it as a therizinosauroid, a right scapula
Scapula
In anatomy, the scapula , omo, or shoulder blade, is the bone that connects the humerus with the clavicle ....
, ten dorsal vertebrae, ribs, a partial ilium
Ilium
-Places:* Ilion or, Latinized, Ilium, another name for the legendary city of Troy, hence the title of Homer's Iliad*Ilium , an ancient city in Epirus...
and the pubes. In 2008 another partial postcranial skeleton was described, specimen FRDC-GSJB-2004-001 found in 2004 at the same site. It contains the last three dorsal vertebrae, a sacrum
Sacrum
In vertebrate anatomy the sacrum is a large, triangular bone at the base of the spine and at the upper and back part of the pelvic cavity, where it is inserted like a wedge between the two hip bones. Its upper part connects with the last lumbar vertebra, and bottom part with the coccyx...
of five vertebrae, the first six tail vertebrae, the left half of a pelvis and two thighbones.
Suzhousaurus might be identical to "Nanshiungosaurus
Nanshiungosaurus
Nanshiungosaurus is a genus of therizinosaurian theropod dinosaur from the Cretaceous of China.Two species have been named in the genus: the type species Nanshiungosaurus brevispinus and Nanshiungosaurus bohlini.-Discovery and naming:...
" bohlini, an earlier named therizinosauroid found in the same formation and also known from limited remains. If so, the species name would be "Suzhousaurus bohlini". A comparison is difficult because there is little overlapping material and the holotype of "Nanshiungosaurus" bohlini is lost.
Description
Along with "Nanshiungosaurus" bohlini, which has the same age, Suzhousaurus was one of the largest known Early Cretaceous therizinosauroids. In 2010 Gregory S. PaulGregory 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 the body length at six metres, the weight at 1.3 tonnes. Suzhousaurus is distinguished by a straight flat front part of the ilium and a flattened pubis
Pubis
Pubis may refer to:* Pubis * Mons pubis, a padding of fat that protects the pubis bone...
curving strongly forward forming a hollow front edge of its shaft.
Phylogeny
Li and coauthors, in their description of the genus, assigned Suzhousaurus to the Therizinosauroidea, in a basal position. They performed a cladistic analysisCladistics
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 found the genus to be more derived
Derived
In phylogenetics, a derived trait is a trait that is present in an organism, but was absent in the last common ancestor of the group being considered. This may also refer to structures that are not present in an organism, but were present in its ancestors, i.e. traits that have undergone secondary...
than Beipiaosaurus
Beipiaosaurus
Beipiaosaurus is a genus of therizinosauroid theropod dinosaur from the Early Cretaceous of China.The exact classification of therizinosaurs had in the past been hotly debated, since their prosauropod-like teeth and body structure indicate that they were generally herbivorous, unlike typical...
and Falcarius
Falcarius
Falcarius is a genus of therizinosaurian dinosaur found in east-central Utah, United States. Its name is derived from the word sickle , which scientists have used to describe its unwieldy clawed hands...
, less derived than Alxasaurus
Alxasaurus
Alxasaurus is a genus of therizinosauroid alxasaurid theropod dinosaur from the Early Cretaceous Period of Inner Mongolia. It is one of the earliest known members of the superfamily Therizinosauroidea, but it already possessed the body shape - including the long neck, short tail, and long hand...
and true therizinosaurids, and the sister taxon of Nothronychus
Nothronychus
Nothronychus is a genus of theropod dinosaur classified in the group Therizinosauria, from the Cretaceous of North America.The type species of this dinosaur, Nothronychus mckinleyi, was described by James Kirkland and Douglas G. Wolfe in 2001...
, forming a clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
with it.
An analysis by Lindsay Zanno in 2010 found a more derived position as the sister taxon of the Therizinosauridae
Therizinosauridae
Therizinosauridae is a family of advanced herbivorous or omnivorous theropod dinosaurs. Therizinosaurid fossil remains have been recovered from mid-late Cretaceous Period deposits from Mongolia, China, and the United States.-Classification:...
, as shown by this cladogram
Cladogram
A cladogram is a diagram used in cladistics which shows ancestral relations between organisms, to represent the evolutionary tree of life. Although traditionally such cladograms were generated largely on the basis of morphological characters, DNA and RNA sequencing data and computational...
: