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Date: | Sat, 14 Feb 2004 19:29:08 +1100 |
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do not know why its shaped that way but do know it is the shell that it
inspired Frank Loyd Wright the great architect to design the Guggenheim
Museum.
----- Original Message -----
From: "Andrew Grebneff" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Saturday, February 14, 2004 6:48 AM
Subject: Re: Thatcheria
> >OK. Why does Thatcheria mirabilis have that unusual screwlike shape?
> >I love that shell, but I haven't a clue as to why it's shaped that
> >way.
>
> Several "turrids" have evolved in this direction. Parasyrinx, Aforia
> & Cochlespira leap to mind. Extinct fossil species of Thatcheria are
> somewhat less spectacular, with a sharply-rounded periphery.
> Parsyrinx subalta, a NZ Oligocene-Miocene-boiundary species, can be
> quite spectacular too.
>
> There are 2 ways to develop such sculpture... one is for t he
> periphery to become accentuated by flats developing above & below;
> the other is for a Conus-shaped shell to broaden its shoulder and
> increase the rate of translation along the axis, resulting in a
> steepened suture, exposing more of the previous whorl.
>
> I doubt that there is any ecological reason for Thatcheria to develop
> like this... much evolution occurs just because it CAN, as random
> harmless mutations may become fixed in the genepool.
>
> The keel strengthens that part of the shell, but the surface abapical
> of the keel remain extremely weak.
>
> >My question about Thatcheria mirabilis has always been, What makes
> >it a Turrid?
>
> Turrids are problematic. I refuse to go along with the splitup of the
> family, but embrace wholeheartedly its synonymization with Conidae.
>
> >(Have I heard recently that it was being moved out of the Turridae
> >to a family of its own?)
>
> Don't know. But I wouldn't support it.
>
> >The first time my dad saw a kid selling a bucket of them in Taiwan,
> >I think, he thought they had been manufactured--and didn't buy any.
> >Sure glad he later reconsidered. I love the shape--though I have
> >seen several whose tips are crooked. Evidently the shape is a
> >fragile one.
> >
> >Final thought: you just can't "out-imagine" our Creator!
>
> Which creator?? Each of us has two... Mum & Dad.
> --
> Andrew Grebneff
> Dunedin, New Zealand
> 64 (3) 473-8863
> <[log in to unmask]>
> Fossil preparator
> Seashell, Macintosh & VW/Toyota van nut
> ________________________________
> I want your sinistral gastropods!
> ________________________________
> Opinions in this e-mail are my own, not those of my institution
> _______________________________________________
> A: Because it reverses the logical flow of conversation.
> Q: Why is top posting frowned upon?
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