Brachylophosaurus
Brachylophosaurus was a mid-sized herbivorous dinosaur, a member of the hadrosaur family. It is known from several skeletons and bonebed material from the Judith River Formation of Montana (U.S.) and the Oldman Formation of Alberta province in Canada.[1] They lived about 81–76.7 million years ago.[2]
| Brachylophosaurus Temporal range: Upper Cretaceous
81–76.7 mya | |
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| Fossil nicknamed Roberta | |
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| Genus: | Brachylophosaurus Sternberg, 1953
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Description
This animal had a bony crest, a flat, paddle-like plate over the top of the skull.[3] Some individuals had crests that covered nearly the entire skull roof, while others had shorter, narrower crests.[4][5][6] Other notable features are the unusually long forelimbs and the beak of the upper jaw being wider than other hadrosaurs of the time.[3]
Teeth
Otherwise, Brachylophosaurus was a typical hadrosaur. It reached an adult length of 9 meters (30 ft).[3] Like other hadrosaurs, Brachylophosaurus had cheeks to keep food in the mouth while it chewed with its hundreds of close-fitting teeth.[3] These teeth could be used to chew efficiently.[3] This feature is rare among reptiles, but common among ornithischia like Brachylophosaurus.
Tumours
In 2003, evidence of tumors, including metastatic cancer, was discovered in fossilized Brachylophosaurus skeletons. Rothschild and co-workers tested dinosaur vertebrae for tumors using computerized tomography and fluoroscope screening. Several other hadrosaurs, 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 reason for this is not known.[7]
Complete dinosaur fossils
In 1994, amateur paleontologist Nate Murphy discovered an immaculate, complete and uncrushed brachylophosaur skeleton which he nicknamed "Elvis".[8] 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 young adult brachylophosaur, was discovered.[9][10] It is considered one of the most spectacular dinosaur finds ever, and was included in the Guinness Book of World Records.[11] They subsequently excavated "Roberta", an almost complete slender skeleton, and "Peanut", a partially preserved juvenile with some skin impressions.
Brachylophosaurus Media
Skull cast of the holotype
Skull of Brachylophosaurus canadensis
Specimen MOR 940 seen from above
Size comparison of the hadrosaurid dinosaur Brachylophosaurus. The human silhouette is from
- Silhouette of man standing and facing forward.svg (CC0).*References* * Brachylophosaurus skeletal reconstruction by Scott Hartman *
Restoration of Brachylophosaurus canadensis
Brachylophosaurus tail with tendons - Museum of the Rockies
Premaxilla (A), compared to that of other saurolophines
Comparison of the primary ridges of the tooth crowns in the dentary dental batteries of some hadrosauroid species (all dental batteries in lingual view). (A) Equijubus normani (IVPP V12534).
References
- ↑ Horner, John R.; Weishampel, David B.; Forster, Catherine A (2004). "Hadrosauridae". In Weishampel, David B.; Osmólska, Halszka; Dodson, Peter (eds.). The Dinosauria (2nd ed.). Berkeley: University of California Press. pp. 438–463. ISBN 0-520-24209-2.
- ↑ Arbour, V.M.; Burns, M.E.; Sissons, R.L. (2009). "A redescription of the ankylosaurid dinosaur Dyoplosaurus acutosquameus Parks, 1924 (Ornithischia: Ankylosauria) and a revision of the genus". Journal of Vertebrate Paleontology. 29 (4): 1117–1135. doi:10.1671/039.029.0405. S2CID 85665879.
- ↑ 3.0 3.1 3.2 3.3 3.4 Brachylophosaurus. In: Dodson, Peter et al The Age of Dinosaurs. Publications International. p. 134. ISBN 0-7853-0443-6
- ↑ Prieto-Marquez, Alberto (2005). "New information on the cranium of Brachylophosaurus, with a revision of its phylogenetic position". Journal of Vertebrate Paleontology. 25 (1): 144–156. doi:10.1671/0272-4634(2005)025[0144:NIOTCO]2.0.CO;2. S2CID 85767827.
- ↑ Hopson, James A. (1975). "The evolution of cranial display structures in hadrosaurian dinosaurs". Paleobiology. 1 (1): 21–43. doi:10.1017/S0094837300002165. S2CID 88689241.
- ↑ Weishampel, David B.; Horner, Jack R. (1990). "Hadrosauridae". In Weishampel, David B.; Osmólska, Halszka; Dodson, Peter (eds.). The Dinosauria (1st ed.). Berkeley: University of California Press. pp. 534–561. ISBN 0-520-06727-4.
- ↑ Rothschild, B. M.; Tanke, D. H.; Helbling, M.; Martin, L. D. (November 2003). "Epidemiologic study of tumors in dinosaurs". Naturwissenschaften. 90 (11): 495–500. doi:10.1007/s00114-003-0473-9. ISSN 0028-1042. PMID 14610645. S2CID 13247222.
- ↑ "Brachylophosaurus dinosaur discovery". Judith River Dinosaur Institute. 2002. Archived from the original on 2008-09-08. Retrieved 2008-07-13.
- ↑ Murphy, Nate L.; Trexler, David; Thompson, Mark (2006). ""Leonardo," a mummified Brachylophosaurus from the Judith River Formation". In Carpenter, Kenneth (ed.). Horns and Beaks: Ceratopsian and Ornithopod Dinosaurs. Bloomington and Indianapolis: Indiana University Press. pp. 117–133. ISBN 0-253-34817-X.
- ↑ Dear Mummy: Rare fossil reveals common dinosaur's soft tissue: Science News Online. 2002-10-19. http://www.sciencenews.org/articles/20021019/fob2.asp. Retrieved 2007-07-06.
- ↑ "Brachylophosaurus dinosaur discovery". Judith River Dinosaur Institute. 2002. Archived from the original on 2013-06-20. Retrieved 2008-07-13.