Name: Ankylosaurus
(Fused lizard).
Phonetic: An-kie-lo-sore-us.
Named By: Barnum Brown - 1908.
Classification: Chordata, Reptilia, Dinosauria,
Ornithischia, Thyreophora, Ankylosauridae, Ankylosaurinae.
Species: A. magniventris
(type).
Type: Herbivore.
Size: Based upon comparison to skull size of other
ankylosaurs, the largest known remains of a 64 centimetres long skull
credits Ankylosaurus with being at least 6.25 meters in length. Lack of
overall fossils however makes more exact details uncertain.
Known locations: Canada, Alberta
- Horseshoe Canyon
Formation, Scollard Formation. USA, Montana - Hell
Creek Formation, New
Mexico - Kirtland Formation, Wyoming - Ferris Formation, Lance
Formation.
Time period: Maastrichtian of the Cretaceous.
Fossil representation: Skull, teeth,
osteoderms, vertebrae, limb bones, ribs, tail club, all from
several fossil locations.
It
is something of a paradox that one of the most popular dinosaurs of all
time is understood by some of the most incomplete fossil remains.
What can be gleaned from the available fossil material is that
Ankylosaurus was one of if not the largest of the
group. The
incomplete fossil evidence however has meant that determining the exact
size of Ankylosaurus is problematic and will remain
so until further,
more complete Ankylosaurus remains are discovered.
As
a low browser, Ankylosaurus’s mouth was shaped
for cropping
vegetation with an arrangement of leaf shaped shearing teeth behind.
One thing worthy of note is that there were no grinding teeth,
suggesting that the mouthful was swallowed for processing in a
digestive system developed for un-chewed food.
Analysis
of available skull material suggests that Ankylosaurus
had an
exceptionally well developed sense of smell. This would have been a
good adaption to detect potential predatory dinosaurs since as a low
browser, Ankylosaurus would quite easily have its
vision obscured by
vegetation.
Ankylosaurus
took armour plating to the extreme, even the eyelids
were armoured. Osteoderms ran across its top side and are so
extensive they have often been the best preserved parts of the Animal.
Particularly large plates covered the shoulder and neck area with
smaller pieces in between to allow for movement. Four large horns
radiated out from the base of the skull, perhaps to stop large
predators like Tyrannosaurus
from closing their
mouths around its head.
The
tail club was composed of several overly large osteoderms fused
together with the end vertebrae. Initially conceived as a defence
against predators, it’s plausible that it may have been used for
territorial combat with rivals.
Further reading
- The Ankylosauridae, a new family of armored dinosaurs from the Upper
Cretaceous. - Bulletin of the American Museum of Natural History
24(12):187-201. - Barnum Brown - 1908.
- Redescription of Ankylosaurus magniventris Brown 1908
(Ankylosauridae) from the Upper Cretaceous of the Western Interior of
North America. - Canadian Journal of Earth Sciences. 41 (8): 961–86. -
K. Carpenter - 2004.
- Redescription of Ankylosaurus magniventris Brown
1908
(Ankylosauridae) from the Upper Cretaceous of the Western Interior of
North America. - Canadian Journal of Earth Sciences. 41 (8): 961–86. -
K. Carpenter - 2004.
- Unusual cranial and postcranial anatomy in the archetypal ankylosaur
Ankylosaurus magniventris. - FACETS. 2 (2): 764–794.
- V. M. Arbour
& J. C. Mallon - 2017.