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| Life reconstruction in watercolors of Masiakasaurus by Christopher DiPiazza. |
Masiakasaurus belonged to the family of dinosaurs called noasauridae. They are a branch of the broader group of theropods, called ceratosaurs, which also includes the larger, more well known, Ceratosaurus and Carnotaurus, to name just a few. Noasaurids, specifically were much smaller and more gracile than their relatives, with proportionally small heads and long legs.
The most prominent feature about Masiakasaurus, is its teeth. Unlike the teeth of most theropods, which angle perpendicular to the jaw, the teeth of Masiakasaurus were angled forward in he front of the mouth. This striking appearance was what earned its name as "vicious". Despite its appearance, however, was Masiakasaurus was probably only truly vicious towards much smaller animals. Its tooth arrangement may have been an adaptation for grasping small, fast moving prey, like a moveable cage. The environment Masiakasaurus lived in did have many prey animals in it at the time, thanks to a great fossil record from Cretaceous Madagascar, including frogs, mammals, small crocodilians, and even small birdlike dinosaurs. Another idea that some people have proposed is that Masiakasaurus was a fisher. In fact, we see similar, unrelated examples of teeth like this in many fish-hunting marine reptiles, like Plesiosaurus. The teeth in the back of Masiakasaurus' mouth were more similar to those of other theropods, and would have been for cutting food to be swallowed.
In addition to its teeth, some other notable features about Masiakasaurus would be its neck, which was long and actually not very flexible, which is not the norm compared to other kinds of long-necked theropods. Its hands each had four fingers, but only the first three digits on each had claws.
Masiakasaurus is a great find by paleontology standards because it is known from more than one specimen, so almost all of its anatomy is known. Another interesting thing about Masiakasaurus, is that paleontologists were able to study what they think was its growth pattern based on individual specimens of different sizes that have been found. Based on what the pool of specimens available to work with and by closely examining the kind of bones Masiakasaurus had compared to those of other dinosaurs, it is hypothesized that Masiakasaurus was actually a relatively slow-grower, and would have attained adult size by the time it was about eight years old. This is indeed pretty slow compared to other non-avian dinosaurs that have been studied in the same way and even modern animals that are related to it, like birds, which reach adulthood, in general, much more rapidly. (Anyone who has ever raised a baby chick knows exactly what I'm talking about. Seriously, one minute they are fluffy yellow peeps... blink once and BAM...adult chicken.)
That is all for this week! As always feel free to comment below or on our facebook page!
References
Carrano, M.T.; Sampson, S.D.; Forster, C.A. (2002). "The osteology of Masiakasaurus knopfleri, a small abelisauroid (Dinosauria: Theropoda) from the Late Cretaceous of Madagascar". Journal of Vertebrate Paleontology 22 (3): 510–534.
Carrano, M.T.; Loewen, M.A.; Sertic, J.J.W. (2011). "New materials of Masiakasaurus knopfleri Sampson, Carrano, and Forster, 2001, and implications for the morphology of the Noasauridae (Theropoda: Ceratosauria)". Smithsonian Contributions to Paleobiology 95: 53pp.
Andrew H. Lee & Patrick M. O’Connor (2013) Bone histology confirms determinate growth and small body size in the noasaurid theropod Masiakasaurus knopfleri. Journal of Vertebrate Paleontology 33(4): 865-876.
The most prominent feature about Masiakasaurus, is its teeth. Unlike the teeth of most theropods, which angle perpendicular to the jaw, the teeth of Masiakasaurus were angled forward in he front of the mouth. This striking appearance was what earned its name as "vicious". Despite its appearance, however, was Masiakasaurus was probably only truly vicious towards much smaller animals. Its tooth arrangement may have been an adaptation for grasping small, fast moving prey, like a moveable cage. The environment Masiakasaurus lived in did have many prey animals in it at the time, thanks to a great fossil record from Cretaceous Madagascar, including frogs, mammals, small crocodilians, and even small birdlike dinosaurs. Another idea that some people have proposed is that Masiakasaurus was a fisher. In fact, we see similar, unrelated examples of teeth like this in many fish-hunting marine reptiles, like Plesiosaurus. The teeth in the back of Masiakasaurus' mouth were more similar to those of other theropods, and would have been for cutting food to be swallowed.
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| Masiakasaurus skull, featuring the unique teeth and jaws. CLEARLY it lived during a time before orthodontists. |
In addition to its teeth, some other notable features about Masiakasaurus would be its neck, which was long and actually not very flexible, which is not the norm compared to other kinds of long-necked theropods. Its hands each had four fingers, but only the first three digits on each had claws.
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| Masiakasaurus skeleton on display at the Royal Ontario Museum in Toronto, Canada. |
Masiakasaurus is a great find by paleontology standards because it is known from more than one specimen, so almost all of its anatomy is known. Another interesting thing about Masiakasaurus, is that paleontologists were able to study what they think was its growth pattern based on individual specimens of different sizes that have been found. Based on what the pool of specimens available to work with and by closely examining the kind of bones Masiakasaurus had compared to those of other dinosaurs, it is hypothesized that Masiakasaurus was actually a relatively slow-grower, and would have attained adult size by the time it was about eight years old. This is indeed pretty slow compared to other non-avian dinosaurs that have been studied in the same way and even modern animals that are related to it, like birds, which reach adulthood, in general, much more rapidly. (Anyone who has ever raised a baby chick knows exactly what I'm talking about. Seriously, one minute they are fluffy yellow peeps... blink once and BAM...adult chicken.)
That is all for this week! As always feel free to comment below or on our facebook page!
References
Carrano, M.T.; Sampson, S.D.; Forster, C.A. (2002). "The osteology of Masiakasaurus knopfleri, a small abelisauroid (Dinosauria: Theropoda) from the Late Cretaceous of Madagascar". Journal of Vertebrate Paleontology 22 (3): 510–534.
Carrano, M.T.; Loewen, M.A.; Sertic, J.J.W. (2011). "New materials of Masiakasaurus knopfleri Sampson, Carrano, and Forster, 2001, and implications for the morphology of the Noasauridae (Theropoda: Ceratosauria)". Smithsonian Contributions to Paleobiology 95: 53pp.
Andrew H. Lee & Patrick M. O’Connor (2013) Bone histology confirms determinate growth and small body size in the noasaurid theropod Masiakasaurus knopfleri. Journal of Vertebrate Paleontology 33(4): 865-876.
