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New PLOS One paper on T rex infections
New paper available at
http://www.plosone.org/article/info:doi/10.1371/journal.pone.0007288#top
Common Avian Infection Plagued the Tyrant Dinosaurs
Ewan D. S. Wolff1*, Steven W. Salisbury2,3*, John R. Horner4, David J.
Varricchio5
Tyrannosaurus rex and other tyrannosaurid fossils often display
multiple, smooth-edged full-thickness erosive
lesions on the mandible, either unilaterally or bilaterally. The cause
of these lesions in the Tyrannosaurus rex specimen FMNH
PR2081 (known informally by the name ‘Sue’) has previously been
attributed to actinomycosis, a bacterial bone infection, or
bite wounds from other tyrannosaurids.
Methodology/Principal Findings: We conducted an extensive survey of
tyrannosaurid specimens and identified ten
individuals with full-thickness erosive lesions. These lesions were
described, measured and photographed for comparison
with one another. We also conducted an extensive survey of related
archosaurs for similar lesions. We show here that these
lesions are consistent with those caused by an avian parasitic infection
called trichomonosis, which causes similar
abnormalities on the mandible of modern birds, in particular raptors.
Conclusions/Significance: This finding represents the first evidence for
the ancient evolutionary origin of an avian
transmissible disease in non-avian theropod dinosaurs. It also provides
a valuable insight into the palaeobiology of these
now extinct animals. Based on the frequency with which these lesions
occur, we hypothesize that tyrannosaurids were
commonly infected by a Trichomonas gallinae-like protozoan. For
tyrannosaurid populations, the only non-avian dinosaur
group that show trichomonosis-type lesions, it is likely that the
disease became endemic and spread as a result of
antagonistic intraspecific behavior, consumption of prey infected by a
Trichomonas gallinae-like protozoan and possibly
even cannibalism. The severity of trichomonosis-related lesions in
specimens such as Tyrannosaurus rex FMNH PR2081 and
Tyrannosaurus rex MOR 980, strongly suggests that these animals died as
a direct result of this disease, mostly likely through
starvation.