Re: What the fossil record tells us about trends in pterosaur diversity

[Michael Habib <mhabib5@jhmi.edu>]

David Peters wrote:

> I disagree. Phylograms are particularly instructive.

We can produce a topology, certainly, but if the results of Butler et 
al. are accurate, then attempts to estimate ghost lineage lengths and 
overall time calibrationsare more or less completely muddied, meaning 
that you still can't produce an accurate estimate of diversity through 
time.

> BTW: various pterosaur genera of all shapes, sizes and niches were 
> going extinct left and right long before the advent of birds.

It seems that way, but again, if the apparent diversity of pterosaurs 
in each interval is entirely taphonomic, how do we know that's actually 
true?  It might be that only a very few of those apparent extinctions 
are real, and we're truncating the last occurance dates for many 
lineages.

Cheers,

--Mike


Michael Habib, M.S.
PhD. Candidate
Center for Functional Anatomy and Evolution
Johns Hopkins School of Medicine
1830 E. Monument Street
Baltimore, MD 21205
(443) 280 0181
habib@jhmi.edu