This name used to mean any big, meat-eating dinosaur. Now it is meant
for a group of dinosaurs that share a close ancestor. You can still find
the old definition in many of the old dinosaur (and unfortunately, some of
the newer) books. This group has 3 separate, smaller groups: the Allosaurids,
the Carcharodontids, and the Sinraptorids. These are large animals, but there
is a large space (often oceans) separating them. For this to have happened,
there must have been land bridges connecting the different areas where the
Carnosaurus lived, at least on and off.
Many dinosaurs have been placed into these groups, but only a few of them
are certain, due to how poorly preserved most of the specimens are. All
carnosaurs are very large (over 7 meters) and have large skulls (over
1 meter). These dinosaurs had larger arms that many of the other groups.
These were large enough that they were probably used to hunt for prey.
All of the Carnosaurs had bumps in front of their eyes that stuck out,
giving them a little horn or bump over the eye. Nobody knows what this was
The three definite Allosaurids are the Late Jurassic Allosaurus, which
got to about 12 meters, the Late Jurassic Neovenator, which got to about
8 meters, and the Early Cretaceous Acrocanthosaurus, which got about
12 meters as well. There are other animals that some people call Allosaurids,
but many people think they are just Allosaurus. The two that might be
separate species are Epantarius and Saurophaganax, and both are
very large Allosaurids (up to maybe 15 meters). All of these dinosaurs are
from North America except Neovenator, which is from Europe.
Acrocanthosaurus has been known for years as a dinosaur that had very
long spines on the top of its backbones. They were not as long as the Spinosaurs,
but they are the longest of the Carnosaurs. Although it has been known for 50 years
a well preserved skull has only been found in the past 10. A well preserved
specimen with a skull and complete arm was found that will give new information
when it is described in the near future.
Allosaurus at the Carnegie Museum of Natural History.
There have been at least three dinosaurs placed into this group. All three live
in the Southern continents. These animals are very large. The smallest one
(which has not yet been given a name) is about 10 or 11 meters long. It lived
in South America in the Early Cretaceous. The other
two have been estimated at about 12 meters each. One (Carcharodontosaurus)
is only really known from a few fragments (including a skull that may be 1600 mm
long, although the tip of the snout and the back of the skull were not preserved)
from the Sahara Desert of North Africa. It lived in the Early Cretaceous as well.
Giganotosaurus is also from the Early Cretaceous, but of South America.
It had a skull about 1700 mm long! There is a mount of this skeleton at the
Philidelphia Academy of Science (which was of a fairly complete skeleton) is about
13 meters long. That makes it the largest predatory dinosaur ever to live (although,
see my comparisons page). There are reports of a
jawbone from another Gianotosaurus that is even bigger. If nothing else,
this was at least a group of enormous dinosaurs, even if they were not the biggest.
There are two definite Sinraptorids. Both are from China. Both are from the
Middle or Late Jurassic. Sinraptor and Yangchuanosaurus are both
about 7 to 9 meters long. They share a lot in common. One of the major
differences between them is the shape of the skull. Sinraptor has
a skull that is longer and lower, but Yangchuanosaurus has a skull
that is shorter, but higher. They both have very big skulls, so each one is
as dangerous as the other.
Sinraptor from the Ex-Terra Show.
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