Monolophosaurus
Name:
Monolophosaurus
(Single crested lizard).
Phonetic: Mon-o-low-fo-doer-us.
Named By: Zhao & Currie - 1993.
Classification: Chordata, Reptilia, Dinosauria,
Saurischia, Theropoda, Tetanurae, Megalosauroidea.
Species: M. jiangi (type).
Diet: Carnivore.
Size: 5 meters long.
Known locations: China, Xinjiang - Shishugou
Formation.
Time period: Callovian of the Jurassic.
Fossil representation: Almost complete individual.
The
almost complete specimen of Monolophosaurus was
first discovered in
1984. This exciting find was initially named ‘Jiangjunmiaosaurus’
after Jiangjunmiao, an abandoned inn near where the skeleton was
found, but it was never an official name hence the lack of italics
and its description as a nomen nudum (a name that
is not
required). The actual name did not come until after the fossils had
been properly prepared for study when the name Monolophosaurus
was
finally chosen, a reference to the crest on its head.
Monolophosaurus
is instantly recognisable by the single crest that runs down the centre
of its skull from the eyes to the end of snout. Because this crest is
hollow there has been past speculation that it may have been a
resonating chamber to amplify sounds. The reality however is that the
hollow construction of the crest was merely a weight saving feature so
that the crest did not become so heavy that Monolophosaurus
would have
difficulties moving the head. Monolophosaurus is
not the only crested
theropod dinosaur of the Jurassic, and a study by T. Carr in
2006 raised the question of if the proceratosauroid genus Guanlong
was actually represented by juvenile Monolophosaurus,
though today
both of these genera are still widely treated as being distinct from
one another.
Monolophosaurus
is classed as a tetanuran, or ‘stiff tailed’ theropod which means
that the tail was kept straight by a series of tendons and carried off
the ground like in most well-known theropods such as Tyrannosaurus
and
Allosaurus
rather than being dragged limply along the ground.
Monolophosaurus however has been speculated to be
one of the most
primitive of tetanurans as well as a member of the neo-tetanura
depending upon the views of differing palaeontologists. Out of all
the known Jurassic era theropods, Monolophosaurus
is thought to be
most closely related to Chuandongocoelurus,
a view reinforced by a
study by Benson et al in 2010.
Further reading
- A large crested theropod from the Jurassic of Xinjiang, People's
Republic of China. - Canadian Journal of Earth Sciences 30: 2027–2036.
- Xi-Jin Zhao & Philip J. Currie - 1993.
- Is Guanlong a tyrannosauroid or a subadult Monolophosaurus?
- Journal
of Vertebrate Paleontology 26:48A. - T. Carr - 2006.
- The skull of Monolophosaurus jiangi (Dinosauria:
Theropoda) and its
implications for early theropod phylogeny and evolution. - Zoological
Journal of the Linnean Society 158: 573–607 - Stephen L. Brusatte,
Roger B. J. Benson, Philip J. Currie, Xijin Zhao - 2010.
- The postcranial skeleton of Monolophosaurus jiangi
(Dinosauria:
Theropoda) from the Middle Jurassic of Xinjiang, China, and a review of
Middle Jurassic Chinese theropods. - Geological Magazine 147 (1):
13–27. - Xijin Zhao, Roger B. J. Benson, Stephen L. Brusatte &
Philip J. Currie - 2010.
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