Atrociraptor
Atrociraptor (meaning "savage robber") is a genus of dromaeosaurid theropod dinosaur from the Late Cretaceous (Maastrichtian stage) of Alberta, Canada.

The type (and only) specimen of "Atrociraptor", holotype RTMP 95.166.1, was discovered by Wayne Marshall in 1995, in layers of the Horseshoe Canyon Formation also containing an "Albertosaurus" bonebed, near Drumheller. This bonebed is located at the top of Unit 4 of the Horseshoe Canyon Formation, which dates to about 68.5 million years ago. The only known specimen consists of parts of the upper and lower jaws—both premaxillae, a right maxilla, both dentaries—teeth and numerous small fragments. The skull appears to have been unusually short and tall. The teeth are relatively straight, but they emerge from the tooth sockets at an angle to the jaw line, resulting in a strongly raked row of teeth. A number of isolated teeth (previously referred to "Saurornitholestes") have also been recovered from the Horseshoe Canyon Formation; they can be recognized by their unusually large serrations. 
In 2004 Philip J. Currie and David Varricchio named and described the type species of "Atrociraptor": "Atrociraptor marshalli". The generic name is derived from the Latin "atrox", "savage", and "raptor", "seizer". The specific name honours Marshall.

In 2010 Gregory S. Paul estimated its length at two metres, its weight at fifteen kilogrammes. "Atrociraptor" differs from "Bambiraptor" and other velociraptorines in its more isodont dentition—the teeth have different sizes but the same form—and short deep snout. A skull opening, the maxillary fenestra, is relatively large and positioned right above another opening, the promaxillary fenestra, a condition not known from other species.

"Atrociraptor" was by its describers assigned to the Velociraptorinae within a larger Dromaeosauridae. However, in 2009 Currie published a cladistic analysis showing "Atrociraptor" to be a member of the Saurornitholestinae.
Q34740
genus
Concept
Q130995
dromaeosaurid
Concept
Q188438
theropod
Concept
Q430
dinosaur
Concept
Q338199
Late Cretaceous
TIME
Q278141
Maastrichtian
TIME
Q1123245
stage
Concept
Q1951
Alberta
LOC
Q252730
type
Concept
Q1061403
holotype
Concept
Q1535620
Horseshoe Canyon Formation
LOC
Q40751
Albertosaurus
Concept
Q1012991
Drumheller
LOC
Q3045639
premaxilla
UNK
Q182895
maxilla
Concept
Q16370
dentaries
Concept
Q132174
Saurornitholestes
Concept
Q975470
Philip J. Currie
PER
None
David Varricchio
UNK
Q252730
type species
Concept
Q397
Latin
Concept
Q908437
specific name
Concept
Q764789
Gregory S. Paul
PER
Q1066137
Velociraptorinae
Concept
Q130995
Dromaeosauridae
Concept
Q192210
cladistic
Concept
Q2061904
Saurornitholestinae
Concept
Q134005
Atrociraptor
Concept
Q134005
Atrociraptor
Concept
Q134005
Atrociraptor
Concept
Q134005
Atrociraptor
Concept
Q134005
Atrociraptor
Concept
Q134005
Atrociraptor
Concept
Q134005
Atrociraptor
Concept
1995-01-01T00:00:00Z^^http://www.w3.org/2001/XMLSchema#dateTime
1995
DATE
2004-01-01T00:00:00Z^^http://www.w3.org/2001/XMLSchema#dateTime
2004
DATE
2010-01-01T00:00:00Z^^http://www.w3.org/2001/XMLSchema#dateTime
2010
DATE
2009-01-01T00:00:00Z^^http://www.w3.org/2001/XMLSchema#dateTime
2009
DATE
+4^^http://www.w3.org/2001/XMLSchema#decimal
4
NUMBER
+68.5^^http://www.w3.org/2001/XMLSchema#decimal
68.5
NUMBER
taxon rank
parent taxon
parent taxon
part of
instance of
location of discovery