Re: Two more gaps in the fossil record

Cliff Lundberg (
Sat, 16 Oct 1999 22:10:46 -0700 wrote:
>At 07:59 PM 10/15/1999 -0700, Cliff Lundberg wrote:
>>As to the matter of hollow bones, one may wonder which came first, the
>>light hollow bones that facilitate flight and rapid respiration, or the light
>>that brought selection pressure for such bones. There may have been niches
>>in which lightness and high metabolism was advantageous for a terrestrial
>>organism. For example, in trees or in dry open country, neither of which are
>>likely spots for fossilization.
>Hollow bones break easily, they are a decided disadvantage to a land-living
>creature. If there were an advantage, why no hollow boned mammals today?

I found this on the web, which may be of interest. Note that the subject is
a *saurischian*, not *ornithischian* dinosaur. I quote all the substance of
the web page:

"Hollow Form"

Coelophysis was a small, lightly-built dinosaur that walked on two long legs.
It was about 9 feet long
(2.8 m). It had light, hollow bones (hence its name), a long head with dozens
of small, serrated teeth,
three clawed fingers on its hands, and a long neck.

Coelophysis was a saurischian ("lizard-hipped") dinosaur, and atheropod. Its
further classification is
disputed, but it may be aceratosaurian. It is closely related to
Rioarribasaurus (or may be the
same genus).

Coelophysis lived in the late Triassic period.

Coelophysis was a carnivore, a meat eater. It may also have been a scavenger.
Coelophysis' fossilized
stomach remains have been found containing small reptiles, fish, and other
Coelophysis bones of different
sizes, indicating that it was a cannibal.

Coelophysis probably lived and hunted in packs; this is suggested by the
existence of fossil bonebeds of
Coelophysis (collections of many fossils of one location).

Slightly built, long legged, and very light because of its hollow
bones,Coelophysis was a very fast
bipedal runner. Dinosaur speeds are estimated using their morphology
(characteristics like leg length
and estimated body mass) and fossilized trackways.

Cliff Lundberg  ~  San Francisco  ~