Freethought & Rationalism Archive

Celsus · 07-15-2003, 12:56 AM

More:

Colugo (flying lemur) in flight (related to lemurs, but isn't):

Ptychozoon (genus of gliding geckos):

Wallace's Tree Frog (Rhacophorus nigropalmatus):

Joel

MrDarwin · 07-15-2003, 06:10 AM

Quote:

Originally posted by Celsus
More:

Colugo (flying lemur) in flight (related to lemurs, but isn't):

These are such cool animals. I need to check but I seem to recall that recent molecular studies are suggesting that flying lemurs are the nearest living relatives of bats, which would go a long way towards explaining how true flight evolved.

markfiend · 07-15-2003, 07:46 AM

Quote:

Originally posted by MrDarwin
These are such cool animals. I need to check but I seem to recall that recent molecular studies are suggesting that flying lemurs are the nearest living relatives of bats, which would go a long way towards explaining how true flight evolved.

I thought that the molecular studies showed that fruit-bats are closer to flying lemurs than to other bats, suggesting that flight has evolved four times (insects, birds, "true" bats, fruit-bats) rather than three as had previously been thought.

ps418 · 07-15-2003, 08:38 AM

And let me point out that recently published descriptions of the dromaeosaur Microraptor gui, while not showing "half a wing," which is an absurdity, do show a compelling functional intermediate tetrapteryx stage, and may well have been capable of gliding. According to Xu et al (2003):

Quote:

Recent discoveries suggest that pennaceous feathers are present on Dromaeosauridae17, a non-avian theropod group, and our observations on the newly collected specimens provide new information that is important for understanding the transition towards birds.

The most unusual feature is the attachment of pennaceous feathers to the whole length of the metatarsus (Figs 1a,c, 2g and 3a). They are long and some have asymmetrical vanes like flight feathers (Fig. 3a�d). We exclude the possibility that these are preservation artefacts because we observed this feature in all six specimens in the present study, most of which are represented by well-articulated skeletons. Pennaceous feathers are also associated with the tibia and femur19 and they display symmetrical vanes. In general, the leg feathers are arranged in a pattern similar to wing feathers in modern birds, suggesting the presence of a hindlimb wing. Although there is no modern analogue, our observations are concordant with some early hypotheses25, 26 that there is a tetrapteryx stage in bird evolution.

Recent work shows that basal dromaeosaurs closely resemble Archaeopteryx in flight apparatus7, 8, 20, 27 (except for some differences in limb proportion, such as the longer arm in the latter taxon), and thus dromaeosaurs were pre-adapted for flight. The new discoveries provide further information on soft tissues and greatly improve our knowledge of these close relatives of birds. Asymmetrical pennaceous feathers are suggested to have the aerodynamic function necessary for flight28. The asymmetry is present not only on the forelimb and tail feathers, but also the hindlimb feathers of basal dromaeosaurs (Fig. 3c�f). The forelimb and the leg feathers would make a perfect aerofoil together, analogous to the patagium in bats or gliding animals. These features together suggest that basal dromaeosaurids probably could glide, representing an intermediate stage between the flightless non-avian theropods and the volant avialans. Apparently some non-avian theropods evolved large and highly specialized pennaceous feathers on the leg for aerodynamic function; these features were later reduced and lost in birds, which depend completely on forewings for flight.

From the commentary on Xu et al (2003) by Prum (2003):

Quote:

In a colourful and prescient paper of 1915, however, William Beebe7 proposed that avian flight evolved through a gliding, four-winged� tetrapteryx � stage with wing feathers on both the arms and the legs. Now Xu and colleagues3 describe a small dromaeosaur, Microraptor gui, that sports four wings of
fully modern, asymmetrical feathers on its forelimbs and legs, and looks as if it could have glided straight out of the pages of Beebe�s notebooks.
. . .

The discovery of a logical functional intermediate provides striking support for through an the arboreal�gliding hypothesis of the origin of bird flight.
. . .

Xu et al. also argue that the extensively feathered legs of Microraptorwould have been incompatible with life on the ground. The feathers extend all the way down the leg, much further than they do in Beebe�s mythical tetrapteryx. Dragging your wing feathers in the dirt would doubtless be aerodynamically disadvantageous, but it will require detailed reconstructions of Microraptor�s hindlimbs with feathers attached to rule out the possibility that it could have walked and run.

. . .
Finally, although Xu and colleagues report that Microraptor has the anatomical features of a dromaeosaur, firm conclusions
about the evolution of bird flight will require new systematic analyses incorporating this and other newly discovered theropod species from Liaoning to confirm their phylogenetic position. Sceptics will argue in any case that Microraptor and dromaeosaurs are more closely related to modern birds than is
Archaeopteryx � but then they will also have to address the problem of why a bird that could flap its wings perfectly well would
evolve a second pair of wings.

Prum, 2003. Dinosaurs take to the air. Nature 421, 323-324.

Xu et al, 2003. Four-winged dinosaurs from China. Nature 421, 335-340.

Patrick

Arken · 07-15-2003, 09:15 AM

Let's not forget the flying fish:

And the almost-gliding Basilisk/Jesus Lizard:

Lobstrosity · 07-15-2003, 09:52 AM

Quote:

Originally posted by Asha'man
Wait, we aren't done yet!

Q. What would a quarter of a wing look like?

A. Ever seen a flying snake?

Flying snakes are pretty damn cool.

http://www.flyingsnake.org/video/video.html

nescio · 07-15-2003, 12:55 PM

Quote:

Originally posted by markfiend
I thought that the molecular studies showed that fruit-bats are closer to flying lemurs than to other bats, suggesting that flight has evolved four times (insects, birds, "true" bats, fruit-bats) rather than three as had previously been thought.

Plus the old flying reptiles, pterosaurs and whatnot.

Nic Tamzek · 07-15-2003, 04:39 PM

When I see flying fish, I feel like saying to evolution:

"Come on now, that's just plain silly!"

Demigawd · 07-15-2003, 05:31 PM

Quote:

Originally posted by Nic Tamzek
When I see flying fish, I feel like saying to evolution:

"Come on now, that's just plain silly!"

On the other hand, there are these crabs that can "fire" one of their claws like a trigger on a gun, and use it to stun prey. So, I say, "that's just plain cool!"

BigBadShrubbery · 07-18-2003, 01:35 PM

Quote:

Originally posted by Demigawd
On the other hand, there are these crabs that can "fire" one of their claws like a trigger on a gun, and use it to stun prey. So, I say, "that's just plain cool!"

[Neo]Whoa.[/Neo]

Me wants pictures!

07-15-2003, 12:56 AM	#11
Celsus Veteran Member Join Date: Aug 2001 Location: Singapore Posts: 2,875	Halfwings abound... More: Colugo (flying lemur) in flight (related to lemurs, but isn't): Ptychozoon (genus of gliding geckos): Wallace's Tree Frog (Rhacophorus nigropalmatus): Joel

Thread Tools	Search this Thread
Show Printable Version	Search this Thread: Advanced Search

07-15-2003, 09:15 AM	#15
Arken Veteran Member Join Date: Jun 2003 Location: North Hollywood, CA Posts: 6,303	Let's not forget the flying fish: And the almost-gliding Basilisk/Jesus Lizard:

07-15-2003, 04:39 PM	#18
Nic Tamzek Senior Member Join Date: Jan 2002 Location: California Posts: 646	When I see flying fish, I feel like saying to evolution: "Come on now, that's just plain silly!"

Freethought & Rationalism Archive

The archives are read only.