The deceptive 'dragonet' photo doing
the rounds online (photo-manipulation originator unknown).
The photograph opening this present ShukerNature
blog article has been brought to my attention on numerous occasions with
requests as to whether the animal that it depicts is real.
Some have wondered whether it may be a species of
flying dragon Draco sp. – i.e. one of those famous little agamid lizards
(up to 8 in
long) native to southeastern Asia whose greatly elongated ribs are connected to
one another on each side of its body by a wing-like membrane that enables the
creature to glide passively (though not actively fly) through the air after
leaping from the trunk or branch of a tree.
Beautiful 19th-Century
engraving of flying dragons Draco volans (public domain)
I have even received enquiries as to whether this
photograph was of a real species of dragon, or, alternatively, some gliding lizard-like
reptile that had mysteriously survived from prehistoric times into the present
day. None of these options is correct, of course, though
there were indeed at least three notable and very different types of gliding
lizard-like reptile alive at one time or another in the ancient world.
Although unrelated to the modern-day Draco agamids, Kuehneosaurus latus was outwardly similar, inasmuch as it too possessed wing-like gliding membranes consisting of elongated ribs interconnected on each side by a membrane. However, recent aerodynamic studies indicate that it used these 'wings' not for gliding but rather for parachuting. Up to 2.3 ft long, this species was formally described and named in 1962 by P.L. Robinson, and existed in southwest England during the late Triassic Period, around 237-201 million years ago.
Although unrelated to the modern-day Draco agamids, Kuehneosaurus latus was outwardly similar, inasmuch as it too possessed wing-like gliding membranes consisting of elongated ribs interconnected on each side by a membrane. However, recent aerodynamic studies indicate that it used these 'wings' not for gliding but rather for parachuting. Up to 2.3 ft long, this species was formally described and named in 1962 by P.L. Robinson, and existed in southwest England during the late Triassic Period, around 237-201 million years ago.
Restoration of Kuehneosuchus
latissimus (left) and Kuehneosaurus latus (right) in life (© Nobu Tamura-Wikipedia)
A more basal species was Icarosaurus siefkeri, known from a single specimen found in 1960 by teenager Alfred Siefker while exploring a New Jersey quarry, and came from the Lockatong Formation. It is housed in New York's American Museum of Natural History.
Restoration of Icarosaurus siefkeri in life (© Nobu Tamura-Wikipedia)
The two species variously lived in what is now England, Germany, and Madagascar during the late Permian Period, approximately
260-250 million years ago. Fans of the science-fiction television series Primeval
will know that the aerial reptile kept by the team as a pet and named Rex is a Coelurosauravus,
though Rex is much bigger than known specimens, and is also capable of active,
powered flight, whereas real Coelurosauravus species could only glide
passively.
Restoration of Coelurosauravus
jaekeli, from Germany (© Nobu Tamura-Wikipedia)
Very different again was a third type of
prehistoric gliding lizard-lookalike – Sharovipteryx mirabilis, formally
described in 1971 and known only from its holotype, which had been discovered
in 1965 in
the Madygen Formation, Dzailauchou, on the southwest edge of the Fergana valley in what is now the independent Asian country
of Kyrgyzstan. It dates from the middle-late Triassic Period, approximately
225 million years ago.
What makes this species so distinctive is that
unlike all other reptilian gliders, its gliding membranes surrounded its pelvic
girdle. It belonged to the taxonomic order Protorosauria.
Restoration of Sharovipteryx
mirabilis (© Dmitry Bogdanov-Wikipedia)
But as the dragonet in the photograph opening this
ShukerNature article is none of these creatures, what exactly is it?
In fact, it is a gecko, but not one that has ever
been breathed into life by either Mother Nature or evolution. Its species is
the satanic leaf-tailed gecko Uroplatus phantasticus, named after its
somewhat devilish, fantastical appearance and its leaf-like tail. Formally
described in 1888 by prolific English zoologist George A. Boulenger, and
indigenous to Madagascar, it is the smallest species of leaf-tailed gecko within
the genus Uroplatus, measuring only 2.6-6 in long in total length.
Needless to say, however, although it is certainly
very eyecatching morphologically, this does not extend to its possessing wings.
When I saw the dragonet photograph a while back, I recognised straight away that
it was merely a novel photo-manipulation of some original photograph of U. phantasticus.
Consequently, it did not take long for me to uncover the latter online, which turned
out to have been been snapped by Piotr Naskrecki. And here it is, alongside its
derived dragonet:
The original Uroplatus
phantasticus gecko photograph (left) and the dragonet image derived from it
via photo-manipulation (right) (© Piotr Naskrecki/photo-manipulation originator
unknown)
Another longstanding internet hoax picture is duly
unmasked, though whoever is responsible for creating it from the gecko photograph
remains unidentified.
My thanks to Facebook friend Carl Kelsall for most recently bringing the dragonet photograph to my attention and, in so doing, inspiring me to pen this exposé.
My thanks to Facebook friend Carl Kelsall for most recently bringing the dragonet photograph to my attention and, in so doing, inspiring me to pen this exposé.
Rex from Primeval (© ITV
Studios/ProSieben/Impossible Pictures/Treasure Entertainment/M6 Films)
The aerodynamics of Sharovipteryx mirabilis puzzle me. Putting the center of mass ahead of the center of lift (or rather, drag) is almost essential for stable flight, (compare darts,) but if they're not close together it becomes impossible to keep the nose up. (It can take a bit of thought to understand.) With its torso well ahead of the geometric center of its wing and its skull much further ahead still, Sharovipteryx's centers of mass and lift appear to confine it to suicidal plummeting! Perhaps it dove into water from overhanging tree branches, fishing in a similar manner to certain birds, but diving so close to shore seems terribly risky.
ReplyDeleteThe posterior of the wing membrane would have offered a large aerodynamic control surface if the legs were capable of a strong twisting motion, but is that likely? Something more likely is shown in a skeletal reconstruction on Pterosaur Heresies: a tail fin much larger than in Dmitry Bogdanov's reconstruction here. If it was horizontal and the tail was strong enough, such a large fin on the end of such a long tail may very well have given it the ability to lift its nose to glide horizontally.
But I'm forgetting its canards -- the control surfaces on the back of its head and its arms. Such anterior control surfaces tend to instability but can be very effective. Perhaps there is no need to speculate about the tail after all.
Almost regardless of the canards, having the center of mass so far forward of the center of lift indicates the creature may have needed to glide very fast to maintain control. The canards would have given great maneuverability in the vertical axis, while the webbed toes at the ends of its wings may, at speed, have been used to steer by differential drag. Perhaps the tail was used for control, or perhaps just for stability. A picture thus emerges of a very fast, maneuverable little flyer, perhaps hunting insects, turning sharply to catch them. It would have been a marvelous sight! :)
Finally, there's the matter of it looking like a supersonic aircraft. Why? Well, :) if I understand right, it was a very early lizard. (I suppose that's what "basal" means.) Thus, it existed an exceptionally long time ago. We know Earth's atmospheric composition was somewhat different in the time of the dinosaurs; what about Sharovipteryx's time? Supposing the atmosphere back then was much denser than it is today, the speed of sound may have been low enough to make this possible, :) especially at low altitudes I don't think it could have flown much faster than Mach 1 though. (Mach numbers are always relative to the speed of sound in the air surrounding the aircraft.) If it did exceed the speed of sound, differential drag from the toes would have offered extreme lateral maneuverability.