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Re: Cost in Aquatic Birds etc.



This is already my 7th message today...

----- Original Message -----
From: "Williams, Tim" <TiJaWi@agron.iastate.edu>
Sent: Monday, March 25, 2002 3:56 PM

> [...] Craciformes.  The hallux is short or high on the foot,
> but nevertheless participates in securing a grip on branches.

I have here beautiful drawings of Cracidae: *Crax rubra*, *Nothocrax
urumutum*, *Penelope purpurascens* and *Ortalis vetula*. All are illustrated
as perching. The picture of *Nothocrax* doesn't show the feet, but those of
all others show halluces that originate as far down as the other toes,
unlike Archie, *Microraptor*, *Caudipteryx* etc., and are considerably
longer than in the latter. Even though none of them seems to reach the
morphology of *Sinornis*.

> Ebel's swim-to-flight model has resurfaced again on the DML.  There are
some
> pretty loopy theories out there on the origin of avian flight, but this
must
> be one of the top contenders.

There are much worse hypotheses. Such as the ground-down one --
parachuting --> gliding --> flying, but not from trees but from various
rocks etc. on the ground. "Gives a selective advantage on slippery
terrain"... LOL. So much for attempts at a compromise between contradicting
hypotheses. :-)

> Like Thulborn's 1985 theory, it takes a very
> literal (and littoral) view of _Archaeopteryx_'s habitat in shaping the
> wing.

I wouldn't say so. Even though this is not how Ebel developed the idea, it
is conceivable to start with a dipper (instead of a hoatzin or a
roadrunner), to develop the hypothesis then, and then to find that Archie
can be shoehorned into it. :-)

----- Original Message -----
From: "Jerzy Dyczkowski" <jerzyd@poczta.ibb.waw.pl>
Sent: Monday, March 25, 2002 3:19 PM
Subject: Re: Velociraptor profiles + swimming/flying etc.

> A number of modern birds swim using wings [...] All have short,
> robust wings, shortened hindlegs and short tails, not typical of
> maniraptors.

No living animal I can think of has a tail like Archie's. Maybe such a tail
is an alternative. On the other hand, the generally short legs and tails of
(*Sapeornis* + Pygostylia) might, eventually, be an adaptation to just this.
Hm.

> No bird known to me broods (that is warms) young with it's wings. [...]

True.

> Some birds cover the well-grown
> young with wings against sun or rain, but this is rare thing.

This is actually pretty common. Other list members know more details.