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Injuries in (running) hadrosaurs



 Since 1979, I've worked in Dinosaur Provincial Park (DPP), the mecca of
hadrosaurs, and have studied their osteopathy in detail for the past 7
years. There is lots of evidence for pathology in this group, some of which
I will relate here. From collecting many hundreds of specimens and seeing
thousands of others in the field, it is apparent to me that hadrosaurs were
either aggressive to each other, highly accident-prone, or both. I also
believe hadrosaurs were bipedal most of the time, but could drop down on all
fours for feeding, drinking or slow casual walking while feeding. I cannot
envision a running quadrupedal hadrosaur. Consider the slenderness of the
metacarpals, manal hoof reduction or loss, and especially the poorly
ossified carpals and resultant weak wrist. Injuries one might expect from an
animal falling down that put its arms out to break the fall could also be
expected to break bone on occasion. When we look at the ample isolated or
associated forelimb material from DPP and other North American areas, we see
that manal pathology is extremely rare. I've never seen or heard of anything
in DPP relating to manal injury. Roy Moodie described some fractured
metacarpals in an Anatosaurus some years ago and the BHI has a fractured and
healed Edmontosaurus metacarpal. Moodie also reported a fractured humerus in
Hypacrosaurus which is supposed to be at AMNH but I have not been able to
track it down, and would be grateful if anyone out there can shed more light
on this specimen. Rib fractures, some multiple in number, have been reported
in specimens of Parasaurolophus (which also has related vetebral trauma) and
Prosaurolophus. Hind leg injuries are known. Isolated tibiae show infectious
processes, similar to those recently described in one of Tom Rich's
Australian hypsilophodonts. Fibular fractures are known too. Infected
metatarsals and pedal phalanges are occassionally seen. Some of the latter
are quite spectacular and suggest the distal portion of the digit must have
been sloughed off long before death. How I would like to find the limping
trackway of an affected individual! Surprisingly, serious pelvic fractures
are known. We have the paired and well healed (fused along entire shaft
length) ischia of an unspeciated lambeosaurine which show evidence of a
severe bilateral fracture of the ischia, about 1/4 below the proximal end.
This is the most severe non-fatal bone injury in a hadrosaur that I've seen
or heard of. Now onto hadrosaur tails which believe me got damaged a lot.
Lots of neural spine fractures are found on the proximal tail region. Here
the spine has been buckled and to some degree folded downwards as if a graet
weight has pressed down on it from above. In the 1989 SVP, I presented an
idea that these fractures may represent injuries in females, and incurred
during mating, where, during copulation, some of the great weight of the
male pressing down on her tail could cause ther elongate and relatively
fragile neural spines to fracture. I have recieved alot of flak over this
idea, but have, and still, welcome any alternative ideas. The only other
thing I'ver been able to conger up is where the animal is laying on its back
and the caudal neural spines are collapsing under its own body weight. It is
important to know that juvenile and subadult hadrosaur caudal neural spines
show absolutely no evidence of similar fractures. This seems logical as they
would no be engaging in mating activities. Further on down the tail we
observe neural spine fractures and fusions, nearly always associated with
crush fractures, where the distal end of the tail was evidently accidently
stepped on by a conspecific and the vertebrae crushed into multiple pieces
(2-5 in number per vertebra- OUCH!), and then later on fused back together.
However, the deep cracks between the fused pieces remain and testify as to
the owners previous grief. Some of these vertebrae fused together at odd
angles so the animal would have had the last foot or two of its tail angled
off to on side at about a 45 degree angle. Some distal tail injuries
appeared so bad that it is likely the distal portion would have been
amputated at the time of injury, or became infected and dropped off. It
would be nice to seen some hadrosaur reconstructions showing animals with
tail damage as it is quite evident in DPP hadrosaurs. I should mention that
cranial injuries are known too, the most interesting I've come across is a
bilateral fracture of the dentaries of the Brachylophosaurus in our galleries.

 Thought this might be of interest to some readers.

 Thanks to those who sent sympathy emails regarding my poor recovery
following my recent dental surgery. Lost 6 pounds but I am almost 100%
healthy again. 

 
 Darren Tanke, Technician I, Dinosaur Research Program, Royal Tyrrell Museum
of Palaeontology, Box 7500, Drumheller, AB, Canada T0J 0Y0. (403) 823-7707;
(403) 823-7131 (fax). Paleo Interests: fossil identification, collection and
preparation, centrosaurine ceratopsians, Upper Cretaceous vertebrate faunas
of North America and East Asia, paleopathology; senior editor on annotated
bibliography of extinct/extant vertebrate dental pathology, osteopathy and
related topics (9,300 entries as of Feb. 7, 1996).