Brachylophosaurus
Encyclopedia
Brachylophosaurus was a mid-sized member of the hadrosaurid
family of dinosaur
s. It is known from several skeleton
s and bonebed material from the Judith River Formation
of Montana
and the Oldman Formation
of Alberta
, living about 76.5 million years ago.
This animal is notable for its bony crest, which forms a flat, paddle-like plate over the top of the skull
. Some individuals had crests that covered nearly the entire skull roof, while others had shorter, narrower crests. Some researchers have suggested it was used for pushing contests, but it may not have been strong enough for this. Other notable features are the unusually long forelimbs and the beak of the upper jaw being wider than other contemporary hadrosaurs.
Apart from the above, Brachylophosaurus was a typical hadrosaur which reached an adult length of 9 meters (30 ft). Like other hadrosaurs, Brachylophosaurus possessed features like cheeks to keep fodder in the mouth and dental batteries consisting of hundreds of teeth. These teeth could be used to chew efficiently, a feature rare among reptiles, but common among ornithischian dinosaurs like Brachylophosaurus.
In 2003, evidence of tumor
s, including hemangioma
s, desmoplastic fibroma, metastatic cancer, and osteoblastoma
was discovered in fossilized Brachylophosaurus skeletons. Rothschild et al. tested dinosaur vertebrae for tumors using computerized tomography and fluoroscope screening. Several other hadrosaurids, including Edmontosaurus, Gilmoreosaurus, and Bactrosaurus, also tested positive. Although more than 10,000 fossils were examined in this manner, the tumors were limited to Brachylophosaurus and closely related genera. The tumors may have been caused by environmental factors or genetic propensity.
(or Kritosaurus
as it was known at the time). This remained the only described specimen until the 1980s, when Jack Horner
described B. goodwini in 1988. This species was found in the Judith River Formation
of Montana. Later work indicated that the differences were probably not enough to justify the second species, and that some of the perceived differences were due to a misoriented skull bone. Brachylophosaurus has subsequently become better known from fossils found in Montanta than Alberta, despite its species name canadensis.
In 1994, amateur paleontologist Nate Murphy discovered an immaculate, complete and uncrushed brachylophosaur skeleton which he nicknamed "Elvis". More impressive finds lay ahead for Murphy and his team from the Judith River Dinosaur Institute. In 2000, "Leonardo", a fully articulated and partially mummified skeleton of a subadult brachylophosaur, was discovered. It is considered one of the most spectacular dinosaur finds ever, and was included in the Guinness Book of World Records. They subsequently excavated "Roberta", an almost complete gracile skeleton, and "Peanut", a partially preserved juvenile with some skin impressions. In May 2008, Steven Cowan, public-relations coordinator at the Houston Museum of Natural Science, discovered a Brachylophosaurus skeleton subsequently dubbed "Marco" from the same area as Leonardo.
Hadrosaurid
Hadrosaurids or duck-billed dinosaurs are members of the family Hadrosauridae, and include ornithopods such as Edmontosaurus and Parasaurolophus. They were common herbivores in the Upper Cretaceous Period of what are now Asia, Europe and North America. They are descendants of the Upper...
family of 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...
s. It is known from several skeleton
Skeleton
The skeleton is the body part that forms the supporting structure of an organism. There are two different skeletal types: the exoskeleton, which is the stable outer shell of an organism, and the endoskeleton, which forms the support structure inside the body.In a figurative sense, skeleton can...
s and bonebed material from the Judith River Formation
Judith River Formation
The Judith River Formation is a fossil-bearing geologic formation in Montana, and is part of the Judith River Group. It dates to the upper Cretaceous, between 80 and 75 million years ago, corresponding to the "Judithian" land vertebrate age...
of Montana
Montana
Montana is a state in the Western United States. The western third of Montana contains numerous mountain ranges. Smaller, "island ranges" are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains. This geographical fact is reflected in the state's name,...
and the Oldman Formation
Oldman Formation
The Oldman Formation is the middle member of the Judith River Group, a major geologic unit in southern Alberta. The formation is widely recognized as bearing a great number of well preserved dinosaur skeletons, as well as other fossils.-Age:...
of Alberta
Alberta
Alberta is a province of Canada. It had an estimated population of 3.7 million in 2010 making it the most populous of Canada's three prairie provinces...
, living about 76.5 million years ago.
Description
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...
. Some individuals had crests that covered nearly the entire skull roof, while others had shorter, narrower crests. Some researchers have suggested it was used for pushing contests, but it may not have been strong enough for this. Other notable features are the unusually long forelimbs and the beak of the upper jaw being wider than other contemporary hadrosaurs.
Apart from the above, Brachylophosaurus was a typical hadrosaur which reached an adult length of 9 meters (30 ft). Like other hadrosaurs, Brachylophosaurus possessed features like cheeks to keep fodder in the mouth and dental batteries consisting of hundreds of teeth. These teeth could be used to chew efficiently, a feature rare among reptiles, but common among ornithischian dinosaurs like Brachylophosaurus.
In 2003, evidence of tumor
Tumor
A tumor or tumour is commonly used as a synonym for a neoplasm that appears enlarged in size. Tumor is not synonymous with cancer...
s, including hemangioma
Hemangioma
A hemangioma of infancy is a benign self-involuting tumor of endothelial cells, the cells that line blood vessels. It usually appears during the first weeks of life and sometimes resolves by age 10. In more severe case hemangioma may have permanency, if not treated by a physician...
s, desmoplastic fibroma, metastatic cancer, and osteoblastoma
Osteoblastoma
Osteoblastoma is an uncommon osteoid tissue-forming primary neoplasm of the bone.It has clinical and histologic manifestations similar to those of osteoid osteoma; therefore, some consider the two tumors to be variants of the same disease, with osteoblastoma representing a giant osteoid osteoma...
was discovered in fossilized Brachylophosaurus skeletons. Rothschild et al. tested dinosaur vertebrae for tumors using computerized tomography and fluoroscope screening. Several other hadrosaurids, including Edmontosaurus, Gilmoreosaurus, and Bactrosaurus, also tested positive. Although more than 10,000 fossils were examined in this manner, the tumors were limited to Brachylophosaurus and closely related genera. The tumors may have been caused by environmental factors or genetic propensity.
Discovery and later finds
Brachylophosaurus was first described by Charles M. Sternberg in 1953 for a skull and partial skeleton which had been found in 1936, and at first thought to belong to GryposaurusGryposaurus
Gryposaurus was a genus of duckbilled dinosaur that lived about 83 to 75.5 million years ago, in the Late Cretaceous of North America...
(or Kritosaurus
Kritosaurus
Kritosaurus is an incompletely known but historically important genus of hadrosaurid dinosaur. It lived about 73 million years ago, in the Late Cretaceous of North America...
as it was known at the time). This remained the only described specimen until the 1980s, when Jack Horner
Jack Horner (paleontologist)
John "Jack" R. Horner is an American paleontologist who discovered and named Maiasaura, providing the first clear evidence that some dinosaurs cared for their young. He is one of the best-known paleontologists in the United States...
described B. goodwini in 1988. This species was found in the Judith River Formation
Judith River Formation
The Judith River Formation is a fossil-bearing geologic formation in Montana, and is part of the Judith River Group. It dates to the upper Cretaceous, between 80 and 75 million years ago, corresponding to the "Judithian" land vertebrate age...
of Montana. Later work indicated that the differences were probably not enough to justify the second species, and that some of the perceived differences were due to a misoriented skull bone. Brachylophosaurus has subsequently become better known from fossils found in Montanta than Alberta, despite its species name canadensis.
Habitat
Some of the less common hadrosaurs in the Dinosaur Park Formation of Dinosaur Provincial Park like Brachylophosaurus may represent the remains of individuals who died while migrating through the region. They might also have had a more upland habitat where they may have nested or fed.External links
- The Judith River Dinosaur Institute
- Brachylophosaurus from SkeletalDrawing.com
- Brachylophosaurus at DinoData