Re: The Lost Dinosaurs Of Egypt ... and insects

["David Marjanovic" <david.marjanovic@gmx.at>]

----- Original Message -----
From: "Williams, Tim" <TiJaWi@agron.iastate.edu>
Sent: Tuesday, June 04, 2002 11:33 PM

> The decline of volant mega-insects (especially Odonata) in the Mesozoic
may
> also be due to the rise of the Pterosauria rather than a drop in O2 in the
> atmosphere.

Was there a _decline_ _in_ the Mesozoic?
http://tolweb.org/tree?group=Odonata&contgroup=Pterygota appears to say
Protodonata, which contains *Meganeuropsis permiana* (72 cm wingspan)
(interesting... I used to think they weren't dragonflies at all), is
confined to the Carboniferous and Permian. Not to mention that Pterosauria
appears only in the Late Triassic with presumed fish eaters, and that a
recent paper _mentions_ (Fig. 8) that the air's oxygen content dropped from
30 % (all-time high) (not 35 %) to below 15 % around the P-Tr boundary (the
model has a pretty low time resolution), while it was pretty unimpressed by
other mass extinctions.

Paper:

Robert A. Berner: Examination of hypotheses for the Permo-Triassic boundary
extinction by carbon cycle modeling, PNAS 99(7) (2 April 2002)

"Amended GEOCARB III" model taken from ref. 19 =

Berner, R. A. & Kothavala, Z. (2001) Am. J. Sci. 301, 182 -- 304

Short comments to the impressive post on big fish...
It's *Xiphactinus* with only one n.
Maybe *Dunkleosteus* had lungs, too... *Bothriolepis* had lungs, and some
new trees get Placodermi and Osteichthyes as sister groups.
What about *Titanichthys*, the supposed 23 m arthrodire? Is it a
misinterpreted *Dunkleosteus*?