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Majungasaurus
formerly Majungatholus atopus
(Sues & Taquet,1979) |
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Name Means: |
"Flesh Bull" |
Length: |
24 Feet (7.5m) |
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Pronounced: |
car-no-Tore -us |
Weight: |
1 ton (960 kilos) |
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When it lived: |
Middle Cretaceous - 115 MYA |
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Where found: |
Madagascar, Africa |
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When fossils are discovered
that are from no known species, they are described and often given a
name, even though their is not enough material to really identify
animal they came from. This is the case with Majungatholus.
It was originally named for an isolated skull fragment thought to
belong to a pachycephalosaur, or dome-headed dinosaur.
In 1998, paleontologist/anatomist Scott Sampson from the New York College
of Osteopathic Medicine at the New York Institute of Technology
discovered far more complete fossils on what is now the island of Madagascar
Uncovered in separate pieces on the island of Madagascar (off the
southeast coast of Africa), the skull of the dinosaur called
Majungatholus is one of the best preserved dinosaur skulls ever
found. The pieces literally fit together like a jigsaw puzzle!
Speaking of his new discovery,
Sampson said, "It's the kind of face that only a mother
could love. It had textured, convoluted bone all over the
surface of the skull which probably had skin tightly adhering to it.
It had this horn-like structure on the top of the head between the
eyes and another projection at the back of the skull as well."
Sampson doesn't know for sure what the protrusions were for, but he
does know one thing. It was damn ugly – and terrifying. "Although the
brain is smaller than the size of a fist, this thing was definitely a
predator…it's got a mouthful of razor-sharp teeth, walked on hind
legs, and would have been pretty quick."
Majungatholus atopus
was a meat-eating dinosaur, a theropod. It was at the top of the
food chain in its locale. It probably ate sauropods, long-necked
plant-eaters and other large dinosaurs. The name Majungatholus
is derived from "Majunga," a district of Madagascar and "tholus,"
which means dome in Latin.
Majungatholus belongs to the group of dinosaurs called
abelisaurids, which until now were only found in India and South
America.
While tyrannosaurs ruled the northern hemisphere, a group of dinosaurs
called abelisaurs roamed the southern half of the world. Majungatholus is very
similar to the horned dinosaur Carnotaurus, which is found in
in Argentina. The discovery of this new species in Madagascar,
so far from its relatives in India and South America, has implications
for plate tectonics. In particular, the continent of Gondwanaland may
have had a connecting land-bridge from South America through
Antarctica to India-Madagascar for longer than believed, allowing
animals like Majungatholus to slowly migrate to new, far flung
habitats.
"Dinosaurs lived at a time when all of the continents were connected,
so we use them to test hypotheses about the timing of the break up of
the Earth's continents," says Sampson. "Until now, people assumed that
South America and Africa broke away as one unit."
Like sharks, dinosaurs have replaceable teeth. So, although many
isolated teeth of the dinosaur were found, it wasn't until Sampson's
discovery that scientists now have an accurate picture of what
Majungatholus looked like.
Also discovered were several bones of another Majungatholus
dinosaur that had teeth marks in it them that could have only been
made by another Majungatholus dinosaur. There was one other discovery of what might have been another
cannibal dinosaur; the Coelophysis bauri, a small
Triassic theropod. This discovery however has not yet been proven and may be unconfirmed.
The discovery of the Majungatholus however has
what geologist Raymond Rogers calls the “smoking gun in the form of
diagnostic tooth marks,” which are “a ‘snapshot’ of a day in the
life-- and death—of Majungatholus." There
is however no evidence to point to whether or not
Majungatholus killed its meals or simply scavenged.
Extensive research later proved that this dinosaur was a cannibal.
In her 2003 press release for the National Science Foundation
(NSF), Cheryl Dybas quoted the NSF program director Richard Lane,
“this research greatly expands our understanding of how dinosaur
species related to each other in the context of their environment, and
also serves as a way of increasing public awareness of and
appreciation for the earth sciences."
Rogers says the evidence for the theory of cannibalism comes from twenty-one
tooth marked elements which were a part of two different Majungatholus
individuals found in two isolated locations on the
island Madagascar. On these bones are distinct sets of tooth marks that point only
to being from the jaws of a Majungatholus dinosaur; the
marks not only match the size and spacing of the teeth found in the
jaws of the Majungatholus, but they also have the same
smaller grooves that match the sharp irregularities of this particular
dinosaur. According to “measurements taken from the
modified bones and the Majungatholus teeth are
comparable.” The set of parallel tooth marks found on one of the bones
matched up with the same approximate inter-tooth spacing as the jaw of
the Majungatholus. This particular
dinosaur also can display an even pattern of tooth eruption that is
evident in several of the bones in the sample.
Rogers
and his colleagues still took no chances in trying to rule out any
other potential dinosaurs or related individuals, which might have
left similar tooth marks on the fossilized bones.
In order to rule out this possibility concretely,
examined the “jaws and teeth of other known meat-eaters in the
Malagasy fauna, including a much smaller carnivorous dinosaur called
Masiakasaurus knopfleri, and two large crocodiles.”
The small size of the only other known theropod from the
region, Masiakasaurus knofleri eliminates it from having
been able to leave the tooth marks found on the bones, which were
definitely from a larger dinosaur. The early forms
of the crocodiles were also ruled out because, “their robust, conical
teeth were too blunt, too irregularly spaced, too variable in height,
too variable in orientation and too variably positioned” to be have
caused the narrow U shaped grooves found in the bones.
After all of this research and examination, Rogers and his
associates concluded that only the Majungatholus had the
jaws and teeth capable of inflicting the damage they saw on the
fossilized bones they had discovered. This, along
with the data from three separate bone-beds that points to
Majungatholus regularly de-fleshing carcasses shows that this
dinosaur is the closest researchers have come as of yet to finding
cannibalism among dinosaurs.
was quoted as saying, “despite the bad press that human cannibals
receive, this discovery of cannibalism in a theropod dinosaur should
come as no big surprise.”;
Cannibalism is a natural tactic that is somewhat common among
animals past and present.“ At least fourteen
species of mammalian carnivores kill and eat members of their own
species, and numerous reptilian and avian taxa also practice
cannibalism.” What makes this discovery important is that previously there
had been little to no concrete evidence that cannibalism existed among
dinosaurs. |
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Edugraphics.Net | Feenixx Publishing |
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