Re: Cretaceous taeniodont

[John Bois <jbois@umd5.umd.edu>]

On Fri, 9 Apr 2004, Phil Bigelow wrote:

> I have often wondered why there are no unambiguous examples of fossorial
> non-avian dinosaurs.

Body plan.  Dinosaurs were primitively bipedal.  Presumably, this was part
of the package that contributed to their early success.  I was just
re-reading Orwell's brilliant essay on mining.  Two-legged
transport in the confines of tunnels is a nightmare.  This could be part
of the reason, at least.  Many large dinsoaurs were secondarily on four.
The fact that no small dinosaurs did this (so far) _may_ indicate that
others had the edge here.

> This doesn't appear to be a matter of competition for a niche.  Consider
> that mammals and lizards both inhabit and exploit the subterranean world,
> and both have done so since at least the mid Mesozoic.

Lizards and mammals may share the same habitat; they are _not_ niche
competitors. Potential differences: forage at different times, tolerate
different heat regimes, etc., etc.