RE: Predatory *baby* dinosaurs of the world

["Thomas R. Holtz, Jr." <tholtz@geol.umd.edu>]

> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
> GOBI 2010

> I was watching TLC last night, a rather interesting show called "When
> Dinosaurs Ruled".

Incidentally, for long time dino documentary watchers, you can see that
effects footage from several previous documentary series (e.g., Ultimate
Guide to T. rex, various PaleoWorld episodes, etc.) have been pieced
together with some new material.

> It mentioned a 65 foot long Tyrannosaur, found near Ft. Peck I
> think. Now, I
> was wondering if I heard the show wrong...'cause isn't 65 feet a
> LOT bigger
> than the normal 'rex?

That would indeed be MUCH bigger.  However, as of yet, none of the
individual skeletal measurements provided suggest the individual was any
bigger (if even as big) as Sue: search the dinosaur list archives under
"Rigby" and "rex" for various discussions and calculations on that topic.

> The show also said there was another adult and a juvinile at the site...
> How big was the supposed juvinile? What did it look like, in
> comparison to
> the adults? What did it's skull look like?

Absolutely none of th is has been described, and in fact I don't know that
any elements of the skulls of the smaller individuals are known: remember,
complete skeletons are VERY VERY VERY rare: most of the time all you have a
bits and parts of a skeleton.

> The show also mentioned another "Fammily" of Tyrannosaurs was
> found by Peter
> Larson (isn't he in jail or something?),

He's been out for some time now.

> this included Sue, a 'male' a juvinile and a baby with a 10-inch skull.
> What did the baby's skull look like?
> What did the juvinile's skull look like?
> Were did the animals look like in comparison to the adults?
> How big were the animals?

The baby looks like a lacrimal.  Okay, that's all of the baby's skull I've
seen: I don't know if there is any more of it.  I don't recall what (if
anything) of the mid-sized specimen was preserved.

(Be careful of taking documentary statements at their word.  The process can
go:
Scientist to filmmaker: "And we have a bone of a juvenile..."
Filmaker to scientist: "How big a juvenile?"
Scientist to filmmaker: "Well, scaling it to other specimens, I predict a
skull about 8 to 10 inches long."
Filmmmaker to audience: "And a baby with a 10-inch skull was found!".)

>
> Later in the show it mentioned that somewhere there was a site
> where several
> allosaurs had frenzied over sauropod remains, with there being 13
> sauropod
> skeletons and 44 mostly 1/2 grown allosaurs there.
>
> How big were the half grown allosaurs? What did they look like in
> comparison
> to a full grown allosaur? What did their skulls look like?

Didn't watch the whole episode yet, but this has GOT to be the
Cleveland-Lloyd Quarry.  Very few of the skeletons at Cleveland-Lloyd are
articulated: there are a lot of bones mixed together.  The count of 44
individuals is a minimum number of individuals count: you sum up what
isolated bones are found, compare the lists of the different bones (# of
left lacrimals, # of right lacrimals, # of left humeri, # of right humeri,
etc., etc., etc.), and figure out, based on size and numbers of each bone,
the absolute fewest number of individuals that could have lived there.

What do the skulls look like?  Well, nobody has assembled the smaller skulls
together, but one of the large ones (UUVP 6000) is the basis for the famous,
often-reproduced Madsen _Allosaurus fragilis_ drawing.

As for this being a frenzied kill site: Sue Ann Bilbey's 1998 paper in
the Morrison Volume (Modern Geology 22: 87-120) suggests that the
Cleveland-Lloyd quarry might have been a shrinking lake bed in which animals
were mired and sank before too much scavenging could occur, as happens at
some watering holes in Africa at the end of the dry season today.

> Also,
> does anyone know of any other baby predatory dinosaurs found in the world,
> if so, what do their skulls look like,
> how big were they (the skulls and the dinosaur), what did they look like?
> How were they different from the adult dinosaurs?

Yes, baby skulls are known for various predatory dinosaurs: in the case of
Coelophysis, they are shorter and bigger eyed than the adults.  In
tyrannosaurids young individual skulls are lower and more delicate than the
adult.

You might want to check out various places (Carpenter, Hirsch & Horner's
Dinosaur Eggs and Babies, for example) if you are interested in baby
theropods.

Hope this helps.


                Thomas R. Holtz, Jr.
                Vertebrate Paleontologist
Department of Geology           Director, Earth, Life & Time Program
University of Maryland          College Park Scholars
                College Park, MD  20742
http://www.geol.umd.edu/pages/faculty/HOLTZ/holtz.html
http://www.inform.umd.edu/SCHOLAR/programs/elt.html
Phone:  301-405-4084            Email:  tholtz@geol.umd.edu
Fax (Geol):  301-314-9661