RE: Coelacanth article in current NatGeo

["Thomas R. Holtz, Jr." <tholtz@umd.edu>]

> From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu] 
> On Behalf Of Erik Boehm
>
> > >  Maybe my understanding of
> > their diversity is wrong, but it seems odd
> > >  that at one point there were so many fleshy
> > finned fish, and now
> > >  there are almost none.
> > 
> > A couple of mass extinctions.
> 
> Of course, but prior to those, the lobe fins were not 
> restricted to bottom/river dwellers correct? if so, what 
> purpose did those fleshy fins serve?
> 
> Its my understanding the basal lobe fins did not live in 
> rivers, or along the sea floor, where such fins may have been 
> useful for holding the fish against a surface. What was the 
> original use?
> 
While it is true that ancestral sarcopts were likely marine, that doesn't mean 
that they weren't demersel (near-bottom swimmers).
Many modern fish are prefectly good swimmers but hang around rocky or muddy 
surfaces, if for no more reason than nutrients tend to
concentrate there.

Thomas R. Holtz, Jr.
Email: tholtz@umd.edu   Phone: 301-405-4084
Office: Centreville 1216                        
Senior Lecturer, Vertebrate Paleontology
Dept. of Geology, University of Maryland
http://www.geol.umd.edu/~tholtz/
Fax: 301-314-9661               

Faculty Director, Science & Global Change Program, College Park Scholars
http://www.geol.umd.edu/sgc
Fax: 301-314-9843

Mailing Address:        Thomas R. Holtz, Jr.
                        Department of Geology
                        Building 237, Room 1117
                        University of Maryland
                        College Park, MD 20742 USA