Re: Panderichthyids as transitional forms

AChadwick (chadwicka@swac.edu)
Wed, 28 Jun 1995 09:44:32 -6000

Ashby states:
> In place of the conclusion of Warren, Jupp, and Bolton, Glenn
> suggests that the trackway was made by panderichthyids rather than
> tetrapods. He is undaunted by the fact these scientists rejected
> the proposal that the tracks had been made by a tetrapod walking in
> shallow water. They state (p. 185) that this "is an improbable
> solution because such poorly consolidated sediments are unlikely to
> preserve tracks made *subaqueously*" (emphasis mine).

They should take a look at Brand's work on tetrapod trackways in the
Coconino Sandstone. In his experimental work, the underwater
trackways were consistently better preserved than those in any other
environment he tested. However this would be underwater, not shallow
water where the substrate would be bearing unbuoyed weight. Brand's
study of the trackways (originally described as amphibians until McKee
made the sand subaerial, then they all mysteriously became reptilian)
led him to conclude McKee's classic study on the sand was wrong and
that the sand must have been deposited subaqueously. I will post the
relevant references tomorrow.

(I apologize if this was sent twice; I didn't receive a copy.)
Art