Re: Not dinosaurs but chondrichthyans

[Colin McHenry <cmchenry@westserv.net.au>]

Patty Ralrick wrote:

> Hi Lorna,
>
> I recently co-wrote a chondrichthyan guide to Dinosaur Provincial Park 
> in Alberta, Canada with Dr. Don Brinkman of the Royal Tyrrell Museum. 
> After an extensive search the oldest shark I could find was *Hybodus* 
> who was known from the Devonian. Sorry. Wish I could give you an older 
> one, but there doesn't seem to be any known yet. 



er, you might want to check that. Isn't _Hybodus_ Mesozoic?

As far as earliest sharks go (and without having my refs in front of 
me), I seem to rememer the earliest decent specimens (_Cladoselache_? 
_Clamydoselache?_, or some such thing) as being early Devonian, with 
some possible Ordovician/Silurian scales.

If the lower Devonian age for the first sharks is correct, this leads to 
the interesting observation that the (jawed) fish thought of by most 
people as being the most primitive in todays seas were actually the last 
of the major fish groups to appear in the fossil record (admittedly, not 
by much, but anything that gets people to question the old chestnut 
about sharks being some relict primitive group is good in my book. I 
used to emphasise to students that white sharks are late model, highly 
evolved, warm blooded, live young bearing, mammal eating machines). The 
standard doco line about sharks being some relict group of monsters is 
absurd.

Cheers
Colin

> Good luck on your display!
>
> Patty
> **********************************************************
> "Dream as if you'll live forever. Live as if you'll die today"
> James Dean
>
> Patty Ralrick
> Bellevue, NE USA
>
> Lorna wrote:
>
> Hi all,
>
> Is anyone out there up to date with the earliest appearance of
> chondrichthyans? It's Devonian according to the latest edition of 
> Benton's
> Vertebrate Palaeontology, but surely there have recent finds to push that
> back a little earlier. Shark people, please tell me what you know! 
> It's for
> a museum display.
> Lorna
>
> Lorna Steel
> Dinosaur Isle
> culver parade
> sandown
> isle of wight
> po36 8qa
> 01983 404344
>
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--
*****************
Colin McHenry
School of Environmental and Life Sciences (Geology)
University of Newcastle
Callaghan NSW 2308
Tel: +61 2 4921 5404
Fax: + 61 2 4921 6925

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cmchenry@westserv.net.au
Colin.Mchenry@newcastle.edu.au