Hongshanosaurus
Encyclopedia
Hongshanosaurus is a genus
of psittacosaurid ceratopsian dinosaur
from the Early Cretaceous Period (about 125 million years ago) of eastern Asia. Although two skull
s are the only fossil
material described, comparisons with close relatives suggest it was a small, biped
al herbivore
with a bony beak
on the end of both upper and lower jaws. This is one of the many exceptionally well-preserved fossils to be recovered from the Yixian Formation
of Liaoning
, China
.
The generic name Hongshanosaurus is derived from the Mandarin Chinese words 紅 (hóng: "red") and 山 (shān: "hill"), as well as the Greek
word sauros ("lizard") . This name refers to the ancient Hongshan culture
of northeastern China
, who lived in the same general area in which the fossil skull of Hongshanosaurus was found.
The type
and only named species
, H. houi, honors Hou Lianhai, a professor at the Institute of Vertebrate Paleontology and Paleoanthropology
(IVPP) in Beijing
, who curated
the specimen. Genus and species were both named by Chinese paleontologists You Hailu, Xu Xing, and Wang Xiaolin in 2003.
The holotype
specimen of Hongshanosaurus, IVPP V12704, is a juvenile skull, completely preserved except for part of the right side and the tip of the upper jaw. This skull is slightly less than five centimeters (2 in.) long (You et al. 2003). A much larger adult skull was later described, specimen IVPP V12617, which is almost twenty centimeters (8 in.) long. It is very similar to skulls of the closely related Psittacosaurus
, although several differences exist which serve to differentiate the two genera. Hongshanosaurus has a lower skull than any species of Psittacosaurus and the orbit
(eye socket) is elliptical instead of round (You & Xu [2005]; note that Sereno [2010] regarded the differences in proportion as due to crushing and compression of the Hongshanosaurus skulls).
These skulls were recovered from the Yixian Formation of Liaoning, China, which is famous for the exceptional preservation of its fossils, including most of the known feathered dinosaurs
. The age of this formation has been radiometrically dated to the early Aptian
age of the Early Cretaceous
, about 125 million years ago. Several specimens of Psittacosaurus have also been recovered from the Yixian, including one with a row of long bristles on the tail which may have had a display
function in life. As Hongshanosaurus is known only from skull material, it is unknown whether it also had these bristles.
ceratopsians. The more inclusive group Neoceratopsia
is in fact defined to include all ceratopsians more derived
than Psittacosauridae (You & Dodson 2004).
Sereno (2010) regarded Hongshanosaurus as a junior synonym of Psittacosaurus, and potentially the same as P. lujiatunensis. He did not synonymize the two species because of difficulties with the holotype skull of H. houi, instead considering new combination P. houi a nomen dubium
within Psittacosaurus.
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 psittacosaurid ceratopsian 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 Period (about 125 million years ago) of eastern Asia. Although two skull
Skull
The skull is a bony structure in the head of many animals that supports the structures of the face and forms a cavity for the brain.The skull is composed of two parts: the cranium and the mandible. A skull without a mandible is only a cranium. Animals that have skulls are called craniates...
s are the only fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
material described, comparisons with close relatives suggest it was a small, biped
Biped
Bipedalism is a form of terrestrial locomotion where an organism moves by means of its two rear limbs, or legs. An animal or machine that usually moves in a bipedal manner is known as a biped , meaning "two feet"...
al 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...
with a bony beak
Beak
The beak, bill or rostrum is an external anatomical structure of birds which is used for eating and for grooming, manipulating objects, killing prey, fighting, probing for food, courtship and feeding young...
on the end of both upper and lower jaws. This is one of the many exceptionally well-preserved fossils to be recovered from the Yixian Formation
Yixian Formation
The Yixian Formation is a geological formation in Jinzhou, Liaoning, People's Republic of China, that spans 11 million years during the early Cretaceous period...
of 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"...
, 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...
.
Discovery and Species
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...
word sauros ("lizard") . This name refers to the ancient Hongshan culture
Hongshan culture
The Hongshan culture was a Neolithic culture in northeastern China. Hongshan sites have been found in an area stretching from Inner Mongolia to Liaoning, and dated from about 4700 BC to 2900 BC....
of northeastern 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...
, who lived in the same general area in which the fossil skull of Hongshanosaurus was found.
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 named species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
, H. houi, honors Hou Lianhai, a professor at the Institute of Vertebrate Paleontology and Paleoanthropology
Institute of Vertebrate Paleontology and Paleoanthropology
The Institute of Vertebrate Paleontology and Paleoanthropology of China is a prominent research institution and collections repository for fossils, including many dinosaur and pterosaurand cat poo specimens...
(IVPP) in Beijing
Beijing
Beijing , also known as Peking , is the capital of the People's Republic of China and one of the most populous cities in the world, with a population of 19,612,368 as of 2010. The city is the country's political, cultural, and educational center, and home to the headquarters for most of China's...
, who curated
Curator
A curator is a manager or overseer. Traditionally, a curator or keeper of a cultural heritage institution is a content specialist responsible for an institution's collections and involved with the interpretation of heritage material...
the specimen. Genus and species were both named by Chinese paleontologists You Hailu, Xu Xing, and Wang Xiaolin in 2003.
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 of Hongshanosaurus, IVPP V12704, is a juvenile skull, completely preserved except for part of the right side and the tip of the upper jaw. This skull is slightly less than five centimeters (2 in.) long (You et al. 2003). A much larger adult skull was later described, specimen IVPP V12617, which is almost twenty centimeters (8 in.) long. It is very similar to skulls of the closely related Psittacosaurus
Psittacosaurus
Psittacosaurus is a genus of psittacosaurid ceratopsian dinosaur from the Early Cretaceous Period of what is now Asia, about 130 to 100 million years ago. It is notable for being the most species-rich dinosaur genus...
, although several differences exist which serve to differentiate the two genera. Hongshanosaurus has a lower skull than any species of Psittacosaurus and the orbit
Orbit (anatomy)
In anatomy, the orbit is the cavity or socket of the skull in which the eye and its appendages are situated. "Orbit" can refer to the bony socket, or it can also be used to imply the contents...
(eye socket) is elliptical instead of round (You & Xu [2005]; note that Sereno [2010] regarded the differences in proportion as due to crushing and compression of the Hongshanosaurus skulls).
Feathered dinosaurs
The realization that dinosaurs are closely related to birds raised the obvious possibility of feathered dinosaurs. Fossils of Archaeopteryx include well-preserved feathers, but it was not until the early 1990s that clearly non-avialan dinosaur fossils were discovered with preserved feathers...
. The age of this formation has been radiometrically dated to the early 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...
age of 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...
, about 125 million years ago. Several specimens of Psittacosaurus have also been recovered from the Yixian, including one with a row of long bristles on the tail which may have had a display
Animal communication
Animal communication is any behavior on the part of one animal that has an effect on the current or future behaviour of another animal. The study of animal communication, is sometimes called Zoosemiotics has played an important part in the...
function in life. As Hongshanosaurus is known only from skull material, it is unknown whether it also had these bristles.
Classification
Hongshanosaurus was placed in the family Psittacosauridae when it was first described, but has not been included in any phylogenetic analysis since. The only other genus currently classified in this family is Psittacosaurus itself, although that genus includes up to a dozen individual species. Psittacosaurids are extremely basalBasal (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:...
ceratopsians. The more inclusive group Neoceratopsia
Ceratopsia
Ceratopsia or Ceratopia is a group of herbivorous, beaked dinosaurs which thrived in what are now North America, Europe, and Asia, during the Cretaceous Period, although ancestral forms lived earlier, in the Jurassic. The earliest known ceratopsian, Yinlong downsi, lived between 161.2 and 155.7...
is in fact defined to include all ceratopsians 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 Psittacosauridae (You & Dodson 2004).
Sereno (2010) regarded Hongshanosaurus as a junior synonym of Psittacosaurus, and potentially the same as P. lujiatunensis. He did not synonymize the two species because of difficulties with the holotype skull of H. houi, instead considering new combination P. houi a nomen dubium
Nomen dubium
In zoological nomenclature, a nomen dubium is a scientific name that is of unknown or doubtful application...
within Psittacosaurus.