Rothschild, B. M.,
Xiaoting, Z., and L. D. Martin. 2012. Adaptations for marine
habitat and the effect of Triassic and Jurassic predator pressure on
development of decompression syndrome in ichthyosaurs. Naturwissenschaften 99:443–448 DOI 10.1007/s00114-012-0918-0
Abstract - Decompression
syndrome (caisson disease or the “the bends”) resulting in avascular necrosis has been documented in
mosasaurs, sauropterygians, ichthyosaurs, and turtles from the Middle Jurassic
to Late Cretaceous, but it was unclear that this disease occurred as far back
as the Triassic. We have examined a large Triassic sample of ichthyosaurs and
compared it with an equally large post- Triassic sample. Avascular necrosis was
observed in over 15%of LateMiddle Jurassic to Cretaceous ichthyosaurs with the
highest occurrence (18 %) in the Early Cretaceous, but was rare or absent in
geologically older specimens. Triassic reptiles that dive were either
physiologically protected, or rapid changes of their position in the water column
rare and insignificant enough to prevent being recorded in the skeleton. Emergency
surfacing due to a threat from an underwater predator may be the most important
cause of avascular necrosis for air-breathing divers, with relative frequency
of such events documented in the skeleton. Diving in the Triassic appears to
have been a “leisurely” behavior until the evolution of
large predators in the Late Jurassic that forced sudden depth alterations
contributed to a higher occurrence of bends.