[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Waders and fishers




Martin Baeker <martin@turtle.ifw.ing.tu-bs.de> wrote:

My question now is: Where are all the dinosaurian waders and fishers?

At the risk of sounding like a broken record, if you consider birds as a subset of dinosaurs (and in a phylogenetic context, you must) then the question answers itself.

However, if your question is amended to "Did any animals wade or
catch fish in Mesozoic environments before the emergence of
birds?" then you have an excellent point.

Pterosaurs were flying long before birds, and many almost certainly fed on fish. An array of archosauromorphs and lepidosauromorphs no doubt prowled rivers and lakes and coastlines in the Triassic. (I also have a picture I my head of _Tanystropheus_ using its long neck as a fishing line.) Then there's the sea reptiles that no doubt haunted the seaside during the Mesozoic.

They were not there because there were less fishes around in the mesozoic. (I have next to no clue on fish evolution.)

It's not my strong point either. However, there is a view that the rise of teleost fishes was due to the rise of birds: Unlike other fishes, teleosts didn't need to pop their heads up above the water to aerial breathe, and were therefore less exposed to sharp-eyed birds. I'm not sure I agree with the theory, but there you have it.


BTW, I believe the Cretaceous hesperornithids are the stratigraphically earliest example of dinosaurs that were habitually subaquatic. AFAIK, that's around the time that the first putative aquatic mammals appear (_Kollikodon_, _Steropodon_). Are there any examples of pre-mid-Cretaceous aquatic mammals? - I could be wrong on this point.



Tim

_________________________________________________________________
Add photos to your messages with MSN 8. Get 2 months FREE*. http://join.msn.com/?page=features/featuredemail