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Re: Big (M)Al(e)?

I wrote 
> On museum.montana.edu/WWW/PALEOCAT/beccabigal/bigal.html there's a text 
> says "Big Al is an 87% grown, sub-adult, male, Allosaurus fragilis".

Richard W Travsky wrote on December 19th, 2000:
> This link does not work (and their search option just sits there :(  )

The address http://museum.montana.edu/www/paleocat/beccabigal/bigal.html 
works fine with me.
But just in case here's a copy of the text. The original also includes a 
photo section depicting some of the affected bones.

Hope this helps a little bit.


Heinz Peter Bredow




                                       by Rebecca R. Laws 

Paleopathology is the study of disease (congenital, infectious, traumatic, 
toxic, endocrine/metabolic,
neoplastic, and systemic disorders) in the fossil record (Mann and Murphy, 
1990). These abnormalities
preserved in bone reflect life events because they formed while the animal 
was alive. Thus, generally
speaking, pathological bones can be used to reconstruct lifestyles. 

Additionally, certain abnormalities may characterize taxa (i.e. related 
groups of animals). If this is true,
then frequency of abnormalities and location in the body may be diagnostic of 
behavior, environment, and
physiology. If certain abnormalities do not distinguish taxa from one 
another, then what are the
implications for vertebrates as a whole? 

The sub-adult Allosaurus fragilis (MOR 693) with nineteen abnormal skeletal 
elements was discovered in
1991 in the Upper Jurassic Morrison Formation in Big Horn County, Wyoming, at 
what became known
as the "Big Al" site. Although the skeleton was found within a stream channel 
sandstone, the presence of
mud chips in the sandstone matrix and virtual completeness of the skeleton 
showed that the skeleton was
not transported very far, if at all. Affected bones include (Fig. 1): 

  1. ) dorsal rib 3, 

  2.) dorsal rib 4, 

  3.) dorsal rib 5, 

  4. ) dorsal rib 6, 

  5.) dorsal rib 14, 

  6.) cervical vertebra 6, 

  7.) dorsal vertebrae 3, 

  8. ) dorsal vertebrae 8, 

  9.) dorsal vertebrae 13, 

  10.) caudal vertebra 2, 

  11.) chevron 2, 

  12. ) left gastralia 5, 

  13.) right scapula, 

  14.) right manus phalanx I-1, 

  15.) right pes phalanx III-1, 

  16.) left pes phalanx II-3, 

  17.) left metatarsal III, 

  18.) right metatarsal V, and 

  19.) left illium 

In order to interpret their origin, these abnormal bones were compared to 
normal ones.

Pathological bones are also present in some of the theropod (carnivorous 
dinosaur) bones from the
Cleveland-Lloyd dinosaur collection housed predominantly at Brigham Young 
University in Provo, Utah,
and the University of Utah, in Salt Lake City, Utah (Petersen et al., 1972; 
Madsen, 1976); comparisons
are made to bones similar in morphology to those of MOR 693. The cause 
(etiology) of the bone
affliction is diagnosed as resulting from trauma, infection, trauma and 
infection, or aberrancy. The specific
goals of the study of Big Al's abnormalities are to: 1) provide a complete 
description and analysis of the
abnormal bones of this sub-adult A. fragilis, 2) develop a better 
understanding of how the bones of
allosaurs reacted to infection and trauma, and 3) contribute to the 
pathological bone database so that
future comparative studies are possible, and the hypothesis that certain 
abnormalities characterize taxa
may be evaluated. In addition, this analysis provides insight into 
physiology, behavior, and environmental
influences since bone abnormalities record life events. 

Although some pathological allosaur bones have been described (Moodie, 1918; 
Petersen et al., 1972;
Madsen, 1976; Rothschild and Martin, 1993), thorough examination of the 
frequency of damaged bones
has not been done, and thus the occurrence and nature of these abnormalities 
remains poorly understood.
If paleontologists identified, described, and (when possible) interpreted the 
cause of abnormalities, then a
database of the frequency and skeletal distribution of pathologic theropod 
bones could be compiled.
Evaluation of these data would reveal which abnormalities are common for 
Allosaurus and would be
useful for future intraspecific comparative studies (i.e. studies of multiple 
individuals of the same species)
because the frequency of pathology varied significantly between individuals. 
Inter-specific comparison
(i.e. studies of many species) of the frequency and anatomical position of 
pathological bones may show
that certain abnormalities characterize taxa and are diagnostic of their 

In summary: 

1) The lifestyle and behavior of a carnivorous dinosaur probably predisposed 
it to injury. "Big Al" is an
87% grown, sub-adult, male, Allosaurus fragilis, who may have incurred some 
injuries during
competition with other males and pursuit of prey, and some infection while 
standing on carcasses,

2) Allosaurs possessed an immune response which allowed them to live with 
microbial infection in their
bones, probably by keeping it localized. 

3) A comprehensive analysis of a large sample of allosaur bones may reveal 
that certain abnormalities
characterize A. fragilis, and are diagnostic of specific behaviors, 
environmental influences, and
physiology. Hence, the significance of this sub-adult allosaur's 19 abnormal 
bones will be better
understood once a comprehensive study of allosaur pathology is completed.