Re: Dinosaur Genera List update #196

["Jaime A. Headden" <qilongia@yahoo.com>]

David Marjanovic (david.marjanovic@gmx.at) wrote:

<IMHO they are more like *Rahonavis* than *Archaeopteryx*, but not
necessarily more like Pygostylia than *A.* apart from convergences. For
example they have a joint between coracoid and scapula, while *Sapeornis*
has a suture in that place and *Confuciusornis* fuses them like a
pterosaur.>

  My data shows the following features which *Archaeopteryx* and
*Rahonavis* lack, to one degree or another, or are advanced to the level
of *Confuciusornis*, and some features go beyond it, as well.

  1) Sternum has a lateral trabeculum;
  2) coracoid acrocoracoid process at the very proximal end of the bone,
     projecting cranially and not rectangular in form;
  3) Furcular rami are flattened, crescentic in section, broad in section,
     and form a "V" rather than a "U";
  4) Ulna bowed only at the proximal end;
  5) Metacarpal I bears a large extensor flange;
  6) Radius distally broad and overlaps the ulna in a tight, sliding
joint,
     implying the distal end is very crescentic in section itself;
  7) Metacarpal III bowed externally, mcIII extends distally beyond mcII;
  8) Manual digit 1 (mdI) extends to knuckle of mdII, not distal to it;
  9) Ulnare large and well-developed for the carpometacarpal articulation;
 10) Carpometacarpus;
 11) Humerus bears three distal condyles, third formed from entepicondyle;
 12) Ischium has an longate, strut-like proximodorsal process that may or
     may not have articulated with the ilium.

  Cheers,

=====
Jaime A. Headden

  Little steps are often the hardest to take.  We are too used to making leaps 
in the face of adversity, that a simple skip is so hard to do.  We should all 
learn to walk soft, walk small, see the world around us rather than zoom by it.

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

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