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Re: Prehistoric Plankton Predators (PPP for short)



Leedsichthys was predated on by the marine crocs at least, there is a croc
tooth embedded in a ?skull bone of one of these fish (Peterborough museum
collection), the fish survived long enough for the bone to heal up around
the tooth.
>From what is known about the Lower Oxford clay fauna it does look as if
plankton blooms brought in Leedsichthys ,smaller fish and swarms of
cephalopods , these in turn brought in the medium sized  piscivores such as
Ophthalmosaurus , Peloneustes and sharks , following behind the large
predators such as Liopleurodon and Simolestes.
Nick Oliver.
----- Original Message -----
From: "Dino Rampage" <dino_rampage@hotmail.com>
To: <dinosaur@usc.edu>
Sent: Sunday, November 24, 2002 8:45 AM
Subject: Re: Prehistoric Plankton Predators (PPP for short)


> Thanks for all the help. Guess Leedsichthys slipped my mind. So it seems
> that lamniform & orectolobiform sharks evolved planktivorous forms in the
> Late Cretaceous.
>
> By the way, I don't think that krill were necessary in order to sustain
> giant filter-feeding planktonivores; I was trying to visualise a creature
> much like our modern day whale shark, a giant inhabitant of warm tropical
> waters, not the mysticete whales living in frigid polar seas. I think that
> back then, there was still plenty of plankton floating about in the seas;
> copepods & ostracods, the nauplii & larvae of various crustaceans & fish;
if
> ammonite young were planktonic, that would be an additional boost. Let's
not
> forget that today, many fish spawn en masse, or that giant clams & hard
> corals synchronise their spawnings to create a rich planktonic 'soup'
surely
> a bonanza to any animal with the adaptations to filter out the good stuff.
>
> I agree that it is likely that some prehistoric marine reptiles were
> facultatively planktonivorous. The leopard & crabeater seals, which feed
on
> krill but do not filter it out (in the strictest sense) came to mind.
Also,
> I watched this documentary where a blue shark was swimming through a swarm
> of krill, taking large bites out of the red cloud. Maybe cryptoclidids &
> other plesiosaurs, with their interlocking teeth, did take advantage of
> planktonic blooms.
>
> But I'm just wondering whether predation may have had any effect on giant
> plankton feeders; Are there any records of giants like whale sharks,
basking
> sharks & manta rays being attacked by say, great white sharks or orcas?
Just
> imagine... a Leedsichthys cruises along when a Liopleurodon rises out of
the
> deep & before the fish can react, the reptile bites it into half, turning
> the sea red & attracting pterosaurs & sharks for miles around. What I
would
> give to see that...
>
>
>
>
>
>
>
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