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Re: weird jurassic dinobird with very weird feathers

David Marjanovic wrote:

<Forgot to mention that I don't have the book here that describes 
*Scansoriopteryx*. What does its tail look like?>

  The proximal 20 or so caudals are preserved, which increase in length 
distally until the final four or so, which begin decreasing. Relative to the 
hip, I'd estimate the sequence in *Epidexipteryx* should start about where the 
sequence in Scan ends. This implies a potential caudal length of 26+ caudals, 
with a discontinuity in doubt between the sections.

<Neither are any other feathers or any other soft parts preserved on any of the 
limbs. The whole ventral side appears to lack preserved integument or other 
soft parts -- and the color of the sediment there is different. IMHO we're 
dealing with absence of evidence here rather than evidence of absence.>

  There appears to be a dark mass in the body cavity, a light greyer mass in 
the pelvic region, and then the darkened mass dorsal to the skeleton. 
Extra-integumental fibres appear to extend from the hips down the femur and may 
arise from the tibia, implying the limbs were "fluffy", but they may not have 
included the tail. Since *Scansoriopteryx* preserves reticulated squamation on 
the tail, it may have been naked. so why "feathers" on the tail? They may have 
arisen from loss of the tail "fuzz", but it's also likely they persist as part 
of a dorsal caudal fuzziness. They appear to have a "rachis" and it seems to be 
hollow. While this does not argue for pennaceous feathers, it doesn't support 
the body having them. The preserved fibres are virtually identical to those of 
*Beipiaosaurus*. The dorsal "halo" does not correspond to the body margin, 
which may have been moved during fossilization, but neither does it correspond 
to the arm, which overlies a
 critical region of preservation. One should think if the arm were heavily 
"fuzzed" up, you'd see some sensu *Beipiaosaurus*, *Yixianosaurus*, NGMC 91, 
etc. This implies either 1) disarticulation after the halo was "imprinted" 
(unlikely), or 2) lack of pennaceous feathers on the arms (where they'd most 
likely be, aside from the tail, which similarly lacks any OTHER form of 
"fuzz"). Tricky, eh?

  This gives me the impression of a decourously-tailed "monkey" animal with 
short furred arms and long "hairs" on the neck and back which may have been 
mane-like, sensu the maned wolf (yes, it's a fox, I know).

<Not true. In *Epidendrosaurus* the claw of the 3rd finger is considerably 
smaller than the other two.>

  Okay, I may have gotten the unguals mixed up somewhere: The holotype of 
*Epidendrosaurus* appears to show mdIII-4 and mdII-3 of approximately the same 
size, as it is in *Scansoriopteryx*. So this may be a matter of switching the 
unguals. However, the unguals are not "considerably" smaller, since there is 
only one ungual of any size (and only in Epi's type) of a size differentiated 
from the others (implied to be the pollecial ungual).


Jaime A. Headden

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)