Re: Being aquatic was Re: Obdurodon (was Re: Coronosaurus [...])

[Tim Williams <tijawi@gmail.com>]

David Marjanovic <david.marjanovic@gmx.at> wrote:

>> We also know that _Baryonyx_ and _Scipionyx_ ate fish. These
>> non-avian theropods also lack any obvious aquatic adaptations.
>
> They do have adaptations to catching fish. "Aquatic" is usually taken to
> mean "living in water", and *B.* and *S.* didn't live in water.


Yes, I agree.  What I was driving at is that certain theropods (avian
or non-avian) could target aquatic prey without needing to be aquatic.
 As far as we know, non-avian dinosaurs never became highly
specialized for an aquatic lifestyle (I don't know why).  Of course,
birds did; lots of times.


>> and many more show highly  refined perching abilities suggesting they
>> were specialized arborealists.
>
> That's not mutually exclusive with being a specialized piscivore, as
> kingfishers demonstrate today (never mind fish-eating eagles and owls).


Again, I agree.  However, specialized perching birds are rare among
known ornithuromorphs/euornitheans basal to Neornithes.  By contrast,
specialized enantiornithean perchers are quite common.  And they
perched using a hallux that was quite a bit different to that of
neornithean perchers.






Cheers

Tim