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Mososaurs etc



--Original Message-- From: Danvarner@aol.com <: Monday, March 01, 1999 06:40
PM
Re: Cretaceous Kelp Forests


>In a message dated 99-03-01 09:27:45 EST, JJackson writes:
>
><< Darren's talk on marine tetrapods revealed that walruses suck molluscs
>open,
> and also threw some light on a long standing puzzle for me as to why the
> apparently primitive looking mososaurs flourished in the late Cretaceous,
as
> the ichthyosaurs died out.  Apparently the shallow weed-clogged lagoons
> which became much more common at that time, suited the undulating and
> somewhat amphibious mososaurs better.
>  >>
>
>  "somewhat amphibious" ?! Mosasaurs were totally aquatic and a stranding
>would be as lethal to them as it is to a whale. Perhaps it would take
longer
>to asphyxiate, but there would certainly be no hope of escape using paddles
or
>serpentine movements. The anatomical configuration is just not there.
>  But, more to the point, Jackson's post behooves me to ask a question
here.
>Is there any shred of evidence for this kelp forest model of Cretaceous
seas?


These are very good questions you ask, Varner, and I'm glad you asked
them... and I'm sure Naish will be only too pleased to provide you with some
answers!


...and...

--Original Message-- From: Larry Febo <larryf@capital.net>: Sunday, February
28, 1999 06:16 PM
Subject: The "ideal" Eumaniraptoran arm motion


>Sunday, Feb 28, 1999, Patrick Norton wrote:
>
><Just to follow up (I just found the article I was thinking about) Gauthier
>(1986) found a pronounced coracoid tuberosity among the Deinonychosauria as
>well as Avialae. According to him, that is only one of many synapomorphies
>shared by the common ancestor of birds and dienonychosaurs and is related
to
>the folding and unfolding of the hands and arms during prey
capture--motions
>that were apparently similar to the flight stroke.>
>
>Yeah,.... I just read the Holtz article(ABC Science News Online), where
this
>type of arm stroke was somehow beneficial in capturing prey, I`ve seen the
>same mentioned in many other places. I don`t want to "play God" and claim I
>could`ve come up with something better than the flight stroke for capturing
>prey, but come on! To actually claim that this was in some way "ideal" to
me
>sounds rediculous!
>Sure, the things existed like that, T-Rex also existed with those
>ridiculously short forearms, We exist with an appendex...for what?....t o
>give doctors something else to remove?? It seems MUCH more likely, ...to
me,
>that many of these "Avian" features are holdovers from a previous flying
>ancestor and are actually "proof" that these creatures are secondarily
>flightless.
> This arm motion for example, especially with feathers attached, seems the
>aerodynamic drag would only tend to hinder the capturing motion of holding
>these arms out and bringing them together, (like clapping ones hands with
>arms completely outstretched). Try running along, with some pieces of stiff
>cardboard in your hands to approximate the surface drag that would be
>produced if you had feathers attached (enough for near flight conditions)
>and try to catch butterflies (or something)using this type of forearm
>motion, see if it improves things. (PS...don`t let the neighbors see
>you!).And to think of these feathers getting longer (for some reason) as
>some kind of preadaptation for flight without actually hindering Dromie`s
>(or pre -flying Eumaniraptoran`s) cursorial existance...I think,  stretches
>the imagination.
>



Couldn't have been better put.




Finally, I too would like to apologise for the name mix-up between Patrick
Norton and Larry Febo a day or two ago; as Patrick points out, their views
are quite distinct.



JJ