Brachylophosaurus meaning "short-crested lizard" was a mid-sized member of the hadrosaurid family of dinosaurs. It is known from several skeletons and bonebed material from the Judith River Formation of Montana and the Oldman Formation of Alberta, living about 76.5 million years ago.
Discovery and later finds[]
Skull cast of the holotype
Skull of TMP 1990.104.0001 (original, not cast), at the Royal Tyrrell Museum of Palaeontology.
Brachylophosaurus was named and described by Charles Mortram Sternberg in 1953 from a skull and partial skeleton, the holotype NMC 8893 , which he had found in 1936 near Steveville in Alberta and which was initially thought to belong to Gryposaurus or Kritosaurus as it was known at the time. The type species is Brachylophosaurus canadensis . The generic name is derived from the Greek βραχύς/brachys , "short", and λόφος/lophos , "helmet crest". The specific name refers to its Canadian provenance. Later, it was recognized that specimen FMNH PR 862 , a partial skull discovered in 1922, might also be referable to B. canadensis . The type specimen was discovered in a layer of the middle Oldman Formation dating to about 78 million years ago.
Specimen MOR 940 seen from above
6 These 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. However, a 2005 study by Albert Prieto-Márquez concluded that the perceived differences between the two species were either due to individual variation or the result of UCMP 130139 being reconstructed with an upside-down skull crest. B. goodwini would thus have been a junior synonym of B. canadensis . Brachylophosaurus has become better known from fossils found in Montana than in Alberta, despite its specific name; B. canadensis .
Another Canadian find was specimen TMP 90.104.01 , a partial skeleton with skull discovered in 1990 at Manyberries, Alberta. Finds in Montana include specimens MOR 720 , a skull base, MOR 794 , a very complete skeleton with skull of an adult individual, and MOR 940 , another skull base. An entire fossil bed of Brachylophosaurus containing over eight hundred specimens has been discovered near Malta, Montana and has been catalogued under the number MOR 1071.
Fossil nicknamed Roberta
In 1994, amateur paleontologist Nate Murphy discovered a remarkably well-preserved Brachylophosaurus skeleton , which he nicknamed Elvis . Since then, Murphy and his team at the Judith River Dinosaur Institute have made even more impressive finds. In 2000, a fully articulated and partially "mummified" skeleton of a Brachylophosaurus was discovered and named Leonardo . It is considered one of the most spectacular dinosaur finds ever found, and was included in the Guinness Book of World Records . Subsequently, specimens of Roberta , a nearly complete skeleton, and Peanut , a partially preserved juvenile with some skin impressions, were exhumed. In May 2008, Steven Cowan, public relations coordinator for the Houston Museum of Natural Science, discovered a Brachylophosaurus skeleton named Marco from the same area as Leonardo .
Description[]
Size comparison
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 feet). 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.
Distinguishing traits[]
Restoration
In 2015, Jack Horner established some distinctive traits. Two of these are autapomorphies, unique derived characters. The crest formed by the nasal bones is flat and paddle-shaped in adults and largely or completely overhangs the supratemporal fenestra. The posterior border of the prefrontal bone overgrows the frontal bone and further back it turns inwards and downwards to support the base of the crest and contribute to the border of the supratemporal fenestra. In addition, there is one trait that is not unique in itself but forms a unique combination with the two autapomorphies, the anterior branch of the lacrimal bone is extremely elongated and with its tip just touches the maxilla.
Skeleton[]
Partial tail with tendons
The head of Brachylophosaurus is elongated. It is broad at the rear and very narrow along most of the length of the snout. However, the upper beak widens abruptly at its rear edge, forming a broad core of bone for a horn sheath. The nostrils are extremely large and between them the nasal bones form a narrow wall of high bone across the top of much of the snout. Farther back, the nasal bones extend horizontally, creating a flat, tongue-shaped skull crest that overgrows, and ultimately overhangs, most of the skull roof. The crest is not hollow but consists of massive bone. The crest has a low longitudinal ridge at the midline.
The maxilla, the tooth-bearing bone of the upper jaw, is rather elongated at the front. Its tooth positions increase over the animal's lifetime, ranging from thirty-three in younger individuals to forty-eight in the holotype. The teeth are stacked in a tooth battery, with up to three teeth per position. The battery forms a sharp, inward-sloping cutting edge, with one or two teeth per position contributing to the wearing surface. Further back, the lower jugal and quadrate bones are laterally extended, so that the skull is much wider at its rear lower edges than on the upper surface, resulting in a trapezoid-shaped profile in posterior view.
Soft tissues[]
Underside of "Leonardo"'s head and neck, showing skin impressions
Several so-called "mummies" provide information about the soft tissues of Brachylophosaurus . These "mummies" actually consist of natural casts formed in the stone matrix surrounding the skeleton, preserving the body outline and showing imprints on the skin. The best studied "mummy" has been "Leonardo", a specimen whose 90% of the casting surface is covered by imprints. Generally, the surface is close to the bones, which could be caused by desiccation before burial or the compressive action of the covering sediment. An exception is the region around the right shoulder, which shows the approximately six centimeter thick profile of muscles. "Leonardo" also indicates that the base of the neck was strongly muscled and that the upper neck profile of soft tissue was set in an elevated position, running much higher than usually reconstructed in drawings that tended to follow the curvature of the spine, the curve between the front back and the head.
On the snout, the remains of a broad keratin beak are visible. Skin impressions show many folds and a structure of small polygonal scales. On the back a midline frill made up of triangular or axe-shaped projections is present. These appear to be individually separated and positioned as extensions of each neural spine of the vertebral column. The second, third, and fourth fingers of the hand are contained in a shared soft tissue "mitten." Examination of Leonardo's stomach also reveals that the dinosaur was parasitized by small, needle-like worms covered in fine bristles. The discovery indicates that other dinosaur species could have been hosts to similar parasites.
More about Brachylophosaurus[]
Only three complete fossils of the hadrosaur, or duck-billed dinosaur, Brachylophosaurus have ever been found, but they're so amazingly well-preserved that (as paleontologists often do) they were immediately given nicknames: Elvis, Leonardo and Roberta. (The same research team also found a fourth, incomplete fossil of a juvenile, which they dubbed Peanut.)
Although it's named for the unusually short crest on its head (short, that is, for a hadrosaur), Brachylophosaurus stood out more for its thick, downward-turning beak, which some paleontologists take as evidence that the males of this genus head-butted one another for the attention of females.
The most completely preserved Brachylophosaurus specimen, Leonardo, has been the subject of a 2008 Discovery Channel documentary, Secrets of the Dinosaur Mummy. Here, it's revealed that Leonardo had a birdlike crop on its neck (presumably to aid in digestion) as well as different-sized scales on different parts of its body, among other unique anatomical features. Especially a bite mark left behind from a predatory Tyrannosaur called Daspletosaurus.
Classification[]
Brachylophosaurus is considered an advanced member of the Ornithopoda, it is considered part of the Hadrosauridae family. Within it, it is found in the subfamily Saurolophinae as part of the tribe Brachylophosaurini. Within this, it is closer to Maiasaura , with which it forms a clade, than to Acristavus.
The following cladogram shows the position of Brachylophosaurus canadensis made in 2013 by Alberto Prieto-Márquez et al.
Premaxilla (A), compared to that of other saurolophines
| Saurolophinae |
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Paleobiology[]
Teeth (F)
In 2003, evidence of tumors, including hemangiomas, desmoplastic fibroma, metastatic cancer, and osteoblastoma was discovered in fossilized Brachylophosaurus skeletons. Rothschild et al. tested dinosaur vertebrae for tumors using computerised 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.
Paleoecology[]
Reconstruction of Brachylophosaurus and other dinosaurs of the Judith River Formation
Some of the less common hadrosaurids in the Dinosaur Park Formation of Dinosaur Provincial Park such as Brachylophosaurus may represent the remains of individuals that died while migrating through the region. They may also have had higher ground habitat where they may have nested or fed.
JPInstitute.com Description[]
Brachylophosaurus was one of the smaller duck-billed dinosaurs - if you think 23 feet long is small! It had a tall head and its nose was short and curved down to its beak. Like the other hadrosaurs, it also had hundreds of teeth. You might take having cheeks for granted, but the large cheeks that these dinosaurs had allowed them to chew their food without it falling out of their mouths. This was a big evolutionary step, especially when you have hundreds of teeth and spend much of your day chewing tough plant leaves.
Discovered and initially described by Charles Sternberg, Brachylophosaurus was a fairly typical hadrosaur. It had a very small crest on top of a tall head. The second species of this dinosaur, B. goodwini, may in fact represent gender differentiation rather than another species.
Gallery[]
Appearance in other media[]
Jurassic Park[]
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We're Back! A Dinosaur's Story[]
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Links[]
https://web.archive.org/web/20030707043013/http://www.jpinstitute.com/dinopedia/dinocards/dc_brachy.html https://web.archive.org/web/20080509101306/http://kids.yahoo.com/dinosaurs/149--Brachylophosaurus