Wannanosaurus
Encyclopedia
Wannanosaurus is a genus
of basal
pachycephalosauria
n dinosaur
from the Campanian
-age Upper Cretaceous Xiaoyan Formation
, about 80 million years ago (mya) in what is now Anhui
, China
. The type species
, Wannanosaurus yansiensis, was described by Lian-Hai Hou in 1977.
It is known from a single partial skeleton, including a partial skull roof
and lower jaw, an upper leg
and lower leg
, part of a rib, and other fragments. Because it has a flat skull roof with large openings, it has been considered primitive among pachycephalosaurs. Sometimes it has been classified as a member of the now-deprecated family Homalocephalidae
, now thought to be an unnatural assembly of pachycephalosaurians without domed skulls.
Although its remains are from a very small individual, with a femur length of ~8 centimeters (3.1 in) and an estimated overall length of less than 1 meter (3.3 ft), the fused bones in its skull suggest that it was an adult at death. Like other pachycephalosaurians, it was probably herbivorous
or omnivorous, feeding close to the ground on a variety of plant matter, and possibly insect
s as well.
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 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:...
pachycephalosauria
Pachycephalosauria
Pachycephalosauria is a clade of ornithischian dinosaurs. Well-known genera include Pachycephalosaurus, Stegoceras, Stygimoloch, and Dracorex. Most lived during the Late Cretaceous Period, in what is now North America and Asia. They were all bipedal, herbivorous/omnivorous animals with thick skulls...
n 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 Campanian
Campanian
The Campanian is, in the ICS' geologic timescale, the fifth of six ages of the Late Cretaceous epoch . The Campanian spans the time from 83.5 ± 0.7 Ma to 70.6 ± 0.6 Ma ...
-age Upper Cretaceous Xiaoyan Formation
Xiaoyan Formation
The Xiaoyan Formation is a geological formation in Anhui, China whose strata date back to the Late Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation.-Vertebrate paleofauna:...
, about 80 million years ago (mya) in what is now Anhui
Anhui
Anhui is a province in the People's Republic of China. Located in eastern China across the basins of the Yangtze River and the Huai River, it borders Jiangsu to the east, Zhejiang to the southeast, Jiangxi to the south, Hubei to the southwest, Henan to the northwest, and Shandong for a tiny...
, 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 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...
, Wannanosaurus yansiensis, was described by Lian-Hai Hou in 1977.
It is known from a single partial skeleton, including a partial skull roof
Skull roof
The skull roof , or the roofing bones of the skull are a set of bones covering the brain, eyes and nostrils in bony fishes and all land living vertebrates. The bones are derived from dermal bone, hence the alternative name dermatocranium...
and lower jaw, an upper leg
Femur
The femur , or thigh bone, is the most proximal bone of the leg in tetrapod vertebrates capable of walking or jumping, such as most land mammals, birds, many reptiles such as lizards, and amphibians such as frogs. In vertebrates with four legs such as dogs and horses, the femur is found only in...
and lower leg
Tibia
The tibia , shinbone, or shankbone is the larger and stronger of the two bones in the leg below the knee in vertebrates , and connects the knee with the ankle bones....
, part of a rib, and other fragments. Because it has a flat skull roof with large openings, it has been considered primitive among pachycephalosaurs. Sometimes it has been classified as a member of the now-deprecated family Homalocephalidae
Homalocephale
Homalocephale is a genus of dinosaur belonging to the pachycephalosaurid family, which lived during the late Cretaceous period of what is now Mongolia, 80 million years ago. The genus was described in 1974 by Osmólska & Maryañska, and consists of a single species, H...
, now thought to be an unnatural assembly of pachycephalosaurians without domed skulls.
Although its remains are from a very small individual, with a femur length of ~8 centimeters (3.1 in) and an estimated overall length of less than 1 meter (3.3 ft), the fused bones in its skull suggest that it was an adult at death. Like other pachycephalosaurians, it was probably herbivorous
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...
or omnivorous, feeding close to the ground on a variety of plant matter, and possibly insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
s as well.