Fishapods

With placoderm-like forebears in brackish shallows, perhaps Tiktaalik was a
primitive proto-salamander/reptile, Acanthostega a primitive pelagic
proto-ray-finned fish (with its duplicated digits for better hydrodynamic
propulsion), and Ichthyostega a primitive proto-frog, with its lack of
abdominal ribs allowing the gradually lengthening rear limbs with broad
paddled feet to come far forward to launch or lunge (and later to leap),
"differentiated vertebral column, with a short neck, weird tall neural spines
in the pelvic region, and a tail which is proportionally shorter" sounding a
lot like a short-legged frog, to eventually lose a few digits and fuse the
coccyx, but retain the primitive skin breathing ability and need to reproduce
in shallow later.

See pictures of fishapods
http://scienceblogs.com/tetrapodzoology/2008/04/functional_anatomy_part_i.php

http://en.wikipedia.org/wiki/Tiktaalik
http://en.wikipedia.org/wiki/fishapod