Re: [dinosaur] Fish-to-tetrapod forelimb function evolution (free pdf)

[David Marjanovic <david.marjanovic@gmx.at>]

> We infer that the earliest steps in tetrapod forelimb evolution were related 
> to limb-substrate interactions, whereas specializations for weight support 
> appeared later. Together, these results suggest that competing selective 
> pressures for aquatic and terrestrial environments produced a unique, 
> ancestral âearly tetrapodâ forelimb locomotor mode unlike that of any 
> extant animal.

Isn't it much easier to conclude that these animals walked underwater, e.g. 
through dense vegetation, and not on land at all? That walking on land is an 
exaptation of walking, not a synonym of it?

That's not a new idea I just came up with either. It goes back to the 1980s at 
least.

By the way, Tetrapoda is defined as the crown-group in Phylonyms. The 
tetrapodomorphs investigated in this paper are pretty far away from the crown.