RE: Coelacanth article in current NatGeo

["Choo, Brian" <bchoo@museum.vic.gov.au>]

I'd almost put money down that basal fleshy lobes on paired fins is the default 
setting for the Osteichthyes (ie. bony fish symplesiomorphy) - Guiyu (Silurian 
bony fish which is either a stem-sarcopt or a stem-bony fish) has them. The 
most primitive actinopterygians (Cheirolepis, Osorioichthys, modern Polypterus) 
have well developed basal lobes although with a different internal osteology 
than derived lobe-fins. Dunno...perhaps the lobes were necessary for fin 
support before the axial elements or lepidotrichia became sufficiently 
strengthened or something...

Cheers
Brian

________________________________________
From: owner-DINOSAUR@usc.edu [owner-DINOSAUR@usc.edu] On Behalf Of Erik Boehm 
[erikboehm07@yahoo.com]
Sent: Thursday, 24 February 2011 8:37 AM
To: dinosaur@usc.edu; rtravsky@uwyo.edu
Subject: Re: Coelacanth article in current NatGeo

This reminds me of a question I've had for a while:

What use were lobe-fins before they were adapted into limbs?
Why did the fleshy lobes evolve in the first place?




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