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Re: Big aquatic vertebrates (WAS: Re: Pterosaur size)
Might be support for endothermy in ichthyosaurs and pliosaurs... also, there
are thermodynamic implications for air respiration vs gills. I thimk.
----- Original Message ----
From: Andreas Johansson <email@example.com>
To: firstname.lastname@example.org; email@example.com
Sent: Wednesday, December 13, 2006 11:05:54 AM
Subject: Big aquatic vertebrates (WAS: Re: Pterosaur size)
On 12/13/06, David Marjanovic <firstname.lastname@example.org> wrote:
> As clear as for terrestrial vertebrates, I'd say. You might like the fact
> that the biggest ichthyosaur (and probably the biggest marine vertebrate
> before *Basilosaurus*) was Triassic, though -- but then it is far from the
> ancestry of the later ichthyosaurs.
This reminds me of something I've long found a bit odd - since the
Triassic or so, most of the really big aquatic vertebrates, both
predators and plankton-feeders, have been tetrapods. The whales win in
both categories (sperm whales and blue whales respectively), but even
discounting them the biggest non-tetrapods are beaten by various
marine reptiles, far as I know. (Leedsichthys and whale sharks are
smaller than that mega-ichthyosaur, and the biggest pliosaurs appears
to have out-sized Carcharodon megalodon, the biggest predatory fish I
Land might seem an odd route to maritime gigantism, but it's
apparently the best one. The only explanation I've seen suggested is
that air-breathing is more effective than gill-breathing, even tho the
gill-breathers can breathe continuously.
Why can't you be a non-conformist just like everybody else?