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RE: weird jurassic dinobird with very weird feathers
I should have noted, however, that what I saw as a furcula, in the line
drawing, corresponds to a rib. Oops. No such element is preserved. Contrary to
paravians, the coracoid of the near preserved is preserved inline with the
scapula. Mickey has argued previously that the coracoid shoudl articulate, as
birds do, into a tight angle, and likens the element to *Bambiraptor* in hsi
last post. This element appears to be preserved such that the articular glenoid
is oriented ventrally, rather than posteriorly or laterally. The same element
of the other side is disarticulated from the scapula. This seems at odds with
previous arguments that the shoulder is "incipiently" avian.
Some other observations:
The jugal has a strongly posteriorly ascending process, and may very well
have lacked a contact with the postorbital, which is otherwise poorly preserved
on both slabs. However, what may be the ascending process of the jugal appears
to be expanded distally. This suggests a closed postorbital bar.
The posterior process of the jugal, the quadratojugal ramus, appears to be
forked, and may preserve portions of an element of the quadratjugal itself.
The quadrate (~12.4mm) is about as high as the orbit is tall (~14mm), which
is far from the derived condition in paravians in which the vertical height of
the quadrate is reduced relative to the orbital height or overall cranial
The mandible in aspect is as similar to *Confuciusornis* as said avian is to
an egret. The mandible is strongly downcurved, with prodigious dental roots (at
least 60%+ of the teeth as preserved are above the root/crown margin and the
mandibular edge); there is no invasive process of the surangular into the
external mandibular fenestra, and the fenestra is roughly evenly ovate rather
than oblate (expanded more to one said than the other, as an egg) in shape;
there does not appear to be a large surangular foramen, and there does appear
to be a long, but not deep and short retroarticular process, although the
elements appear broken.
There is a large lachrymal foramen.
The femoral caput does not appear to be elevated above the trochanteric body,
and seems to be subquadrangular with a semi-spherical quality to the
There are no pennate feathers. At least even basal dromaeosaurs,
oviraptorosaurs, and probably troodontids had true feathers. This places the
taxon at least in either 1) a degenerate state, in which case it should lack
features associated with a flight apparatus a la therizinosauroids, or 2) it is
not as close to birds as the authors of the paper positioned it. The matrix
would be better suited to looking at their codings.
The distal ends of the scapula are expanded. This was proposed for
*Scansoriopteryx*, as it was argued the element found on the slab was the
distal end, but others have argued it as the proximal element. A broad distal
expansion is also not in keeping with this taxon's placement closer to birds
than to deinonychosaurians, which produced reduced distal expansions to none at
all, as in Avialae.
I am not sure why an animal that is so closely aligned in morphology to other
"scansoriopterygids" would have a reduce tail, as if the extreme modification
would be coincident with pelvic modifications due to anteriorized center of
gravity; such do not appear to occur, and the dorsal column reminds me of
compsognathids in being long and low, much longer at least than the tibia by
about 20%. Comparatively, *Confuciusornis* dorsal/tibial lengths are close to
equal, *Gallimimus* is roughly 10% longer in the dorsum, and *Velociraptor*
appears to be about 15% or so. (I'm guestimating from images of Scott Hartman's
and Greg Paul's skeletals here.) The body adaptations do not agree with a short
tail, and given the intactness of the distal segment and the disarticulated
aspect of the proximal, I would strongly urge a disconnect, and therefore lack
of confidence as to the tail's length overall.
The ilium appears to have a broad cuppedicus shelf, and MAY have a
supracetabular crest, but that could be an artifact of the image. It (the
supracetabular crest) may be the element that is overlying the proximal pubis.
It is entirely possible the manual phalanges represent portions of digits 1
and 3, not 1 and 2, since the second manual ungual in *Epidendrosaurus* is,
like *Confuciusornis* of all things, smaller than the other two. The unguals in
*Scansoriopteryx* appear of equal size.
Jaime A. Headden
"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)