Hesperosaurus
Encyclopedia
Hesperosaurus was a herbivorous dinosaur
from the Kimmeridgian
to Tithonian
epochs of the Jurassic
period (approximately 150 million years ago), whose fossils are found in the state of Wyoming
in the United States of America
. It is from an older part of the Morrison Formation
, and so a little older than other Morrison Stegosaurs.
Hesperosaurus was a type of stegosaurid
, having alternating plates on its back and four spikes on its tail. The plates on its back were not as tall, but were longer, than in its cousin Stegosaurus
. It had a shorter, broader skull than Stegosaurus and appears most closely related to Dacentrurus
.
by Kenneth Carpenter
and colleagues, who took the name for its location in the western United States. A nearly complete skull and much of the skeleton was found. The only species known is Hesperosaurus mjosi. It is present in stratigraphic zone 1 of the Morrison Formation.
Susannah Maidment and colleagues proposed in 2008 that Hesperosaurus should be considered a synonym of Stegosaurus, with H. mjosi becoming Stegosaurus mjosi.
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 Kimmeridgian
Kimmeridgian
In the geologic timescale, the Kimmeridgian is an age or stage in the Late or Upper Jurassic epoch or series. It spans the time between 155.7 ± 4 Ma and 150.8 ± 4 Ma . The Kimmeridgian follows the Oxfordian and precedes the Tithonian....
to Tithonian
Tithonian
In the geologic timescale the Tithonian is the latest age of the Late Jurassic epoch or the uppermost stage of the Upper Jurassic series. It spans the time between 150.8 ± 4 Ma and 145.5 ± 4 Ma...
epochs of the Jurassic
Jurassic
The Jurassic is a geologic period and system that extends from about Mya to Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...
period (approximately 150 million years ago), whose fossils are found in the state of Wyoming
Wyoming
Wyoming is a state in the mountain region of the Western United States. The western two thirds of the state is covered mostly with the mountain ranges and rangelands in the foothills of the Eastern Rocky Mountains, while the eastern third of the state is high elevation prairie known as the High...
in the United States of America
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. It is from an older part of the Morrison Formation
Morrison Formation
The Morrison Formation is a distinctive sequence of Late Jurassic sedimentary rock that is found in the western United States, which has been the most fertile source of dinosaur fossils in North America. It is composed of mudstone, sandstone, siltstone and limestone and is light grey, greenish...
, and so a little older than other Morrison Stegosaurs.
Hesperosaurus was a type of stegosaurid
Stegosauridae
Stegosauridae is a family of stegosauria, large thyreophorans. They lived longer than other Stegosaurs; while all Huayangosauridae and most of basal stegosaurs died out in Tithonian - Kimmeridgian, stegosauridae survived till Middle Cretaceous. They are usually characterized by triangular plates on...
, having alternating plates on its back and four spikes on its tail. The plates on its back were not as tall, but were longer, than in its cousin Stegosaurus
Stegosaurus
Stegosaurus is a genus of armored stegosaurid dinosaur. They lived during the Late Jurassic period , some 155 to 150 million years ago in what is now western North America. In 2006, a specimen of Stegosaurus was announced from Portugal, showing that they were present in Europe as well...
. It had a shorter, broader skull than Stegosaurus and appears most closely related to Dacentrurus
Dacentrurus
Dacentrurus , originally known as Omosaurus, was a large stegosaur of the Late Jurassic Period .-Description:...
.
Discovery and species
It was described in 20012001 in paleontology
-Newly named insects:-Newly named bony fishes:-Newly named amphibians:-Newly named turtles:-Ichthyosaurs:-Newly named basal lepidosauromorphs:-Newly named plesiosaurs:-Newly named sphenodonts:-Newly named basal archosauromorphs:...
by Kenneth Carpenter
Kenneth Carpenter
Kenneth Carpenter is a paleontologist. He is the museum director of the USU Eastern Prehistoric Museum and author or co-author of a number of books on dinosaurs and Mesozoic life...
and colleagues, who took the name for its location in the western United States. A nearly complete skull and much of the skeleton was found. The only species known is Hesperosaurus mjosi. It is present in stratigraphic zone 1 of the Morrison Formation.
Susannah Maidment and colleagues proposed in 2008 that Hesperosaurus should be considered a synonym of Stegosaurus, with H. mjosi becoming Stegosaurus mjosi.