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Albertosaurus libratus questions

In the ROM (Royal Ontario Museum, in Toronto, Canada), the permanent
dinosaur display includes an Albertosaurus libratus mount, ROM 1247.
(still in the old 70s kangaroo pose.)

There are two things that have been bugging me about this thing's head.

Firstly, there are eight narrow conical premaxillary teeth, about 4 cm
long.  (That's the 'hold ruler in front' value of 'about', there, not an
eyeball guestimate.)  These are closely packed, and touch along their
sides for two thirds of their length or so, until the narrowing of the
tips starts to separate them.  These appear to have a common degree of
curvature, so that they're a bit hooked, rather than straight, but I
have no way to tell if that's a preservational artifact or not.

Secondly, the rostral surface of the pre-maxillary is extremely rugose,
more noteably so than the nasal or the rugose areas above the orbits.

The other dentary and maxillary teeth are about twice the length of the
premaxillary teeth, 7 or 8 cm for the longest, and have the usual
curved-and-serrated, laterally compressed Tyrannosaurid tooth shape, and
appear at least twice as thick across the lingual-to-buccal dimension as
the pre-maxillary teeth are through their circle section.  (the mount's
head is about a foot above *my* head, so the opportunity to hold the
ruler *between* the dentary teeth at a useful angle is not there, alas.)

So -- did this thing have a beak? A horn right on the tip of its nose?
Anyone got any idea why the picket fence pre-maxillary teeth?

graydon@dsl.ca   |  Hige sceal þe heardra, heorte þe cenre,
                 |  mod sceal þe mare þe ure maegen lytlað.
                 |   -- Beorhtwold, "The Battle of Maldon"