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Senter's recent attempt to lump Longisquama with Coelurosauravus got me
interested in that Permian gliding diapsid, close to the base of all living
The second most recent paper on Coelurosauravus was in 1997:
Frey, Sues and Monk 1997
Gliding Mechanism in the Late Permian Reptile Coelurosauravus
SCIENCE -VOL. 275 - 7 MARCH 1997
pdf available at:
In this paper FS&M demonstrated that unlike other gliders and flyers,
Coelurosauravus developed its wing via neomorphic dermal ossifications without
modification to the ribs or limbs, as in other flyers. They reconstructed a
wing in which the rods had a radial disposition originating near the humeral
glenoid and posteriorly no further than 1/3 of the torso. The leading edge of
the wing in their view formed an angle of 75 degrees with the sagittal plane
and the posteriormost wing rods were oriented parallel to the parasagittal
plane. The trailing edge of the wing in their reconstruction terminated well
anterior to the hind limb. They also reported that there was no one-to-one
relationship of the rods and ribs due to the much larger number of rods than
I had no reason to doubt this interpretation until I started diving into the
literature and tracing the specimens. Although FS&M got the main point right,
(dermal ossifications as wing supports) some of the details may be arguable.
1. In my reconstruction (see www.pterosaurinfo.com/coelurosauravus.html) the
wing is broader than FS&M reconstructed it, with a leading edge extending at
right angles to the sagittal plane. This reconstruction was created by rotating
each rib in Photoshop, rather than redrawing it freehand as FS&M seem to have
2. If the posteriormost rods are left parallel to the sagittal plane, they
extend past the posterior pelvis, which means the leg is under the wing.
3. Rather, if the posteriormost rods extend laterally, they can be
reconstructed completely anterior to the hind limb, producing a slightly
narrower wing with rods more closely spaced. Probably a better design for that
reason alone -- but who knows? Jim C.??
4. There are 23 rods in total per side. The first 11 emanate from the first
dorsal rib and form a large bundle proximally, as HS&M noted. However, the
posterior 12 rods appear to be associated with the next 12 dorsal ribs,
one-to-one. Thus half are not radially oriented as HS&M reported in 1997. About
half are though.
5. SMNK 2882 PAL might be a mother. When all of the bones af the main specimen
are accounted for, more remain. In both specimens the skull is the only
disarticulared element. I'd be interested to see if others can reidentify the
bones, especially that unique skull, any other way.
6. The affinities of Coelurosauravus are still an open question. The
metacarpals and metatarsals decrease in length laterally from II to V. When we
find another taxon with this pattern, we might have a clue.
7. The hands and feet, to no one's suprise, appear to be webbed.
8. The pelvis, always hard to see and never rendered previously, is found here
to be quite similar to that of Petrolacosaurus with the addition of a bit of
anterior process on the ilium. Due to this process, if facultatively bipedal in
the manner of the Australian Frillneck, then the spreading of the rib rods may
have had another use -- prior to its use as a gliding membrane -- to increase
the apparent size of Coelurosauravus in the face of rivals and predators.
Interesting notes on reproduction in Draco volans:
It is not known exactly when reproduction occurs, but it is assumed to be in
December and January. Males, and occasionally females, show several displays.
These include the spreading of the wings and a bobbing motion of the entire
body when the two are in close proximity to each other. The male will also
spread his dewlap to a fully erect position and then circle the female three
times before copulation. The female will only show display patterns to stop or
prevent copulation (Hairston, 1957). The female Draco will build a nest for the
eggs by forcing her head into the soil to create a small hole. She will then
lay five eggs into the hole and cover them with dirt, packing the soil on top
of them with a patting motion of her head. For approximately twenty four hours,
the female will guard the eggs fiercely. After this period, no further guarding
occurs. Incubation of the eggs take approximately 32 days (Card, 1994).