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Re: Archie bones



In a message dated 96-02-02 14:51:33 EST, ornstn@inforamp.net (Ronald
Orenstein) writes:

>My God, you weren't kidding!  Okay, let's get this straight:  I am not aware
>of one single feature that Archaeopteryx shares with cormorants and anhingas
>(and I am talking about convergences here, obviously - certainly nobody is
>implying that Archie is a cormorant) that can be interpreted as an
>adaptation for diving.  In fact, though Archie is arguably a pretty
>specialized dinosaur, it strikes me as a very generalized bird.
>
>If you are under the impression that cormorants and anhingas do not show
>skeletal specializations for diving and associated prey capture, you are
>incorrect.  See Johnsgard, "Cormorants, Darters and Pelicans of the World",
>pp. 34-41, for a summary of these.  They include: elongation of the
>postacetabular portion of the pelvis (for attachment of musculature involved
>in foot-propelled diving); well-developed patella; adaptations of the
>cervical vertebrae for thrusting (especially in anhingas); a relatively
>sturdy ribcage (in cormorants) to withstand water pressures; etc.
>
>>
>>Hey, there were lagoons a plenty in Bavaria of 145 Ma. Maybe some of those
>>_Archaeopteryx_ skeletons got there by drowning during dives. Wouldn't it
be
>>neat to find fish scales in the stomach of one of those specimens? Of
>course,
>>this still wouldn't prove they dived after the fish, only that they ate (or
>>scavenged) them.
>
>As you said yourself in relation to proterosuchids, the fact that the
>specimens ended up under water proves nothing, and I know of no feature in
>Archie that suggests aquatic feeding habits.  As I suggested in an earlier
>post, they could have nested on lake islets to avoid predators and flown
>regularly over water to get to feeding grounds (as some nutmeg pigeons do
>today).  

Well, there's one neat idea shot down in flames, eh? So was Larry Martin
incorrect about there being no hollow bones in _Archaeopteryx_? And if this
were the case, namely, that _Archaeopteryx_ bones were solid, it would have
to be a reversal, since many theropod bones were hollow, even pneumatic.
So--why the reversal, if indeed it happened?