Re: Atrociraptor

[Danvarner@aol.com]

npharris@umich.edu (Nick Pharris) writes:
<< What the heck is _Atrociraptor_?  Like Tim, I only got truncated messages, 
and I
notice they're not coming up in the archives, either. >>

Here's Ralph's post. Is there an image floating around somewhere? This dingus 
was first mentioned on the DML back in '96. DV :

<< I can't believe nobody has reported it yet, but here goes!  _Feathered 
Dragons: Studies on the Transition from Dinosaurs to Birds_, edited by Philip 
J. 
Currie, Eva B. Koppelhus, Martin A. Shugar, and Joanna L. Wright, was released 
last week.  I have it in my greedy little manus as I write.  The book, which 
is based on the "Florida Symposium on Dinosaur Bird Evolution" that celebrated 
_Bambiraptor feinbergi_ and an exhibition of some of the Liaoning specimens, 
has many highlights, which I will not detail now for lack of time.  Hopefully, 
someone else on the list will buy the book and offer their comments.  (It 
goes for around $50 US).

I quote the first paragraph from the _Atrociraptor_ paper, which is on pp. 
112-132:

"4. A New Dromaeosaurid from the Horseshoe Canyon Formation (Upper 
Cretaceous) of Alberta, Canada
Philip J. Currie and David J. Varricchio

Abstract
The discovery of a new dromaeosaurid in the Horseshoe Canyon Formation 
(uppermost Campanian-lowermost Maastrichtian, Upper Cretaceous) increases the 
known 
diversity of this interesting group of theropods, considered by many as the 
closest non-avian theropod relatives of _Archaeopteryx_ and other derived 
birds.  The new animal, known from a partial skull, is relatively small.  It 
differs 
from the contemporary _Bambiraptor_, _Saurornitholestes_, and _Velociraptor_ 
in having a short, deep face.  The teeth are more strongly inclined toward the 
throat than they are in most other dromaeosaurids, and are all almost the 
same size.  Phylogenetic analysis suggests that the new dromaeosaurid may 
represent an independent lineage having origins back in the early Cretaceous."

More:

"Taxonomy
Dinosauria Owen,1842
Saurischia Seeley, 1888
Theropoda Marsh, 1881
Dromaeosauridae Matthew and Brown, 1922
Velociraptorinae Barsbold, 1983
_Atrociraptor marshalli_, new genus, new species

Etymology:
"Atroci" is a Latin word meaning savage, whereas "raptor" is Latin for 
robber.  The species is named after Wayne Marshall of East Coulee, Alberta, who 
discovered the type specimen.

Holotype:
TMP 95.166.1, a partial skull that includes premaxillae, the right maxilla, 
the right dentary, portions of the left dentary, teeth, and numerous bone 
fragments.

Locality and age:
The holotype was recovered from strata about 5 m above the Daly Coal Seam #7 
(Gibson 1977) in the Horseshoe Canyon Formation (upper Campanian or lower 
Maastrichtian, Upper Cretaceous) at UTM 12U 372,125E,5,708,055 N, which is 
about 5 
km west of the Royal Tyrell Museum of Paleontology in Drumheller, Alberta.

Diagnosis:
Small velociraptorine, dromaeosaurid theropod that differs from 
_Saurornitholestes_ and _Velociraptor_ in having a shorter, deeper face.  
Subnarial body of 
premaxilla is taller than its anteroposterior length as in _Deinonychus_ and 
possibly _Dromaeosaurus_.  Internarial and maxillary processes of premaxilla 
subparallel and oriented more dorsally than posteriorly.  Larger maxillary 
fenestra than in any other velociraptorines.  Maxillary fenestra is directly 
above 
the promaxillary fenestra, rather than well behind it as in all other 
dromaeosaurids.  Maxillary teeth more strongly inclined toward the throat than 
in all 
other dromaeosaurids except _Bambiraptor_ and _Deinonychus_.  Maxillary 
dentition is essentially isodont."

The cladogram, Figure 4.8, shows it as a sister taxon to _Deinonychus_.  
Based on the Philip Currie's reconstruction, Figure 4.7, the skull would have 
been 
approximately 21 cm long.  I had the pleasure of seeing a display of the 
holotype when I visited the Royal Tyrell last summer, so I knew it was coming!  
By 
the way, I think that Michael Skrepnick's fluffy color portrait of 
_Atrociraptor_ on page 178 is adorable.   

--------
"Dino Guy" Ralph W. Miller III
Docent at the California Academy of Sciences
proud member of the Society of Vertebrate Paleontology >>