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Re: 11th specimen of Archaeopteryx
Yes, sir, Mr. Hartman and I have corresponded about it previously.
It may be true that a lack of humeral remiges corresponds with proportionally
short humeri, or it may not: that is a hypothesis that can be tested (I don't
think it should be assumed a priori). I am finding humeral remiges absent in
sample galliforms (quails) and corvids (jays) in my preliminary pterylographic
An experimental test would be simple: take birds with a humeral length to body
mass ratio the same as the distribution in Archaeopteryx specimens of varying
sizes, cut the humeral feathers, and see if the modern birds can fly and/or
what performance (if any) is lost.
The reason I am skeptical is that the putative "gap" between the body wall and
secondaries that is often mentioned is less of a gap if we consider that the
humerus diverges from the body wall at something near 45 degrees, and that
there is a broad propatagium as well, even in forms as basal as Microraptor.
The gap then is reduced to a small notch between the knee and elbow. I wish I
could attach a small diagram here to demonstrate.
I'll consult my copy of Nitsch's Pterylography and report back.
On Oct 27, 2011, at 6:45 PM, Habib, Michael wrote:
> Yes, that is the presentation I alluded to. Thanks for posting the abstract!
> The modern birds with secondaries filling the inboard wing typically have
> short humeri. Archaeopteryx also does not seem to have angled secondaries.
> Scott Hartman would be the better individual to reply to that particular
> query, though.
> --Mike H.
> Sent from my iPhone
> On Oct 27, 2011, at 5:52 PM, "Jason Brougham" <email@example.com> wrote:
>> Dr. Habib, is this the presentation at SVP Bristol that you mentioned?
>> Also, the literature says that some modern birds do not have humeral
>> remiges, using proximally directed secondaries to fill that role. Is it
>> possible it was the same for Archaeopteryx?
>> Poster Session II, (Thursday)
>> FLIGHT MORPHOLOGY AND LAUNCH DYNAMICS OF BASAL BIRDS, AND
>> THE POTENTIAL FOR COMPETITION WITH PTEROSAURS
>> WEISHAMPEL, David, Johns Hopkins University, Baltimore, MD, USA; HABIB,
>> Johns Hopkins University, Baltimore, MD, USA
>> Birds inherited a bipedal gait and feathered airfoils from their theropod
>> ancestry. These
>> features produce specific tradeoffs with regards to launch, maximum size,
>> lift coefficient,
>> and limb disparity. There are subtle effects related to the use of feathered
>> wings, such as
>> the ability to utilize separated wingtip slots and extensive span reduction,
>> which have
>> also influenced avian flight evolution. Combining information from
>> structural mechanics,
>> aerodynamics, and phylogeny, we conclude that the basal state for avian
>> takeoff was a
>> leaping launch, not a running launch. We find that several morphological
>> features of early
>> birds, inherited from theropod ancestry, predisposed them to radiation in
>> inland habitats. We
>> find that Archaeopteryx could sustain substantial loads on both its
>> forelimbs and hindlimbs,
>> but structural ratios between the forelimb and hindlimb of Archaeopteryx are
>> of limited volancy. Limb strength in Confuciusornis was modest, suggesting
>> an emphasis
>> on cruising flight and limited launch power. We find little evidence to
>> support extensive
>> competition between birds and pterosaurs in the Mesozoic. Prior literature
>> has suggested
>> that pterosaurs competed with early birds for resources and may have helped
>> shape the early
>> evolution of birds. There is some evidence of partitioning between
>> pterosaurs and birds in
>> ecological space. Evidence from the Jehol fauna suggests that pterosaurs
>> dominated near
>> coastlines during the Early Cretaceous, while birds were more important
>> inland. However,
>> flight is a complex character. Flight mechanics vary considerably across
>> volant animals.
>> Some flyers experience only limited competition for resources with other
>> flying species,
>> and might compete most intensely with non-flying taxa. As a baseline for
>> understanding the
>> interactions between Cretaceous birds and pterosaurs, the flight dynamics of
>> the two groups
>> need to be compared in a quantifiable framework. Birds and pterosaurs
>> inherited different
>> morphologies, and this impacted their flight regimes. Comparing the two
>> systems provides
>> a basis for hypotheses related to competition in the Cretaceous, and the
>> influences on early
>> avian evolution.
>> On Oct 27, 2011, at 4:21 PM, Habib, Michael wrote:
>>> Also, the possible (likely) lack of a complete inner wing and the
>>> relatively weak forelimbs (see Weishampel and Habib presentation at SVP
>>> Bristol for the latter; full paper still pending as we are adding to it).
>>> --Mike H.
>>> Sent from my iPhone
>>> On Oct 27, 2011, at 3:55 PM, "David Černý" <firstname.lastname@example.org> wrote:
>>>> David Marjanović <email@example.com> wrote:
>>>>> What are these, other than the apparent inability to lift the wing above
>>>> The (admittedly controversial) feather study of Nudds & Dyke (2010),
>>>> Nudds RL, Dyke GJ 2010 Narrow primary feather rachises in
>>>> _Confuciusornis_ and _Archaeopteryx_ suggest poor flight ability.
>>>> Science 328(5988): 887-9
>>>> David Černý
>> Jason Brougham
>> Senior Principal Preparator
>> American Museum of Natural History
>> (212) 496 3544
Senior Principal Preparator
American Museum of Natural History
(212) 496 3544