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

Re: The ground-nowhere hypothesis on the origin of bird flight

oops! sorry the rush!!
Augusto Haro

2009/10/8 Denver Fowler <df9465@yahoo.co.uk>:
> I suppose I should say "wait for the papers!". Part 1 will be available soon. 
> Part 2 should follow shortly after.
> Of course, the talk at SVP was necessarily abbreviated. This was originally a 
> 50minute lecture, based on two forthcoming papers, compressed into 15 minutes 
> at SVP. Part 1 was submitted for SVP2008 but was rejected, so I had to cram 
> it all into a single talk for this year.
> As for content... I really didn't want to cut the velociraptor slide from 
> part 2, or the piscivore slide from part1, but time constraints required it. 
> In the paper(s) there's lots more discussion on the topics raised here on 
> DML. I don't want to go into things in any detail until the papers come out.
> I'm not saying that what we are proposing is THE answer, but it provides a 
> whole new direction for research, and makes better sense of the peculiar 
> anatomy of these critters, being based in real, commonly observed (and most 
> importantly, directly testable) behaviours, not just hypothetical models.
>  ----------------------------------
> Denver Fowler
> df9465@yahoo.co.uk
> http://www.denverfowler.com
> -----------------------------------
> ----- Original Message ----
> From: Augusto Haro <augustoharo@gmail.com>
> To: keesey@gmail.com
> Cc: DML <dinosaur@usc.edu>
> Sent: Thursday, 8 October, 2009 10:26:24
> Subject: Re: The ground-nowhere hypothesis on the origin of bird flight
> I just have a question by now with Fowler's hypothesis:
> As far as I know, large unguals are restricted to dromaeosaurids among
> paravians (as far as I know, troodontids and avialans have much
> smaller claws), so it seems that killing subequally sized prey should
> not be primitive for paravians, but just an apomorphy of
> dromaeosaurids or a subgroup therein. So it seems difficult for me
> that this predation mode can explain avian flight.
> The paravian primitive condition seems to be a small ungual in pedal
> digit II, perhaps for seriema-like killing of small vertebrates.
> 2009/10/8 T. Michael Keesey <keesey@gmail.com> wrote:
>> Often when a new trait appears, it appears in great abunda
> w inhibitors. Look at the
>> earliest "apo-pterygotan" insects, with 3 pairs of  wings (one pair
>> significantly smaller than the other two), or the earliest
>> "apo-tetrapods", with 8 digits.
> Agree with the insects and the correlations between intracorporal
> homologues. However, the tetrapod polydactyly may represent a
> reduction from an ancestral sarcopterygian condition with many more
> rays than 8, as in dipnoans (if dipnoan fin rays are to be homologized
> with digits, which appear likely; David Marjanovic may know better).