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Fam Jansma wrote-
> The material, at least as far as the text
mentions it, comprimises: a quadrate, partial dentary and poorly > preserved
postdentary section, a partial basioccipital, a poorly preserved series of 5
cervicals, a
> semilunate carpal, the complete metacarpus,
several phalanges and unguals, fragments from the pelvis > and a partial left
foot. Maybe more elements were discovered, but these are the elements mentioned.
The braincase section also includes fragmentary exoccipitals,
the posterior basisphenoid and prootics. No pelvic fragments are
mentioned, but a distal femur is known.
> At a first glance at the age, I thought the
material could be assigned to a specimen of Sinornithoides
> (Currie, P.J., Zhiming, D. 2001),
but as a I started to look at details, some differences appeared.
Russell and Dong (1993) compared the two. They merely
stated the unnamed specimen was subadult, but still 20% larger than
Sinornithoides. Also, the second pedal ungual is relatively smaller and
the distal phalanges of pedal digit III are much shorter.
> According to the text the preserved
basioccipital portion of the braincase in specimen GIN 100/44 had > not
developed the lateral depression, or at least it still lacked the basioccipital
portion of that
> depression.
Which means we should compare it to Sinovenator, which also
lacks the depression. As the unnamed specimen is poorly preserved, and
Sinovenator is sparingly illustrated, this is difficult. Still, the less
constricted third metatarsal of the latter suggests it may be more
primitive.
> But my question is: what is it? Has
it been more thourougly described recently and does someone
> have any additional pictures of this
specimen that I could have? And what other info is available for > the
specimen?
Who knows. My guess is a troodontid phylogenetically
intermediate between Sinovenator and Sinornithoides + other troodontids.
It has not been described since 1987 and no pictures are available outside those
in the original description and The Dinosauria (what else would be illustrated
anyway? the dentary fragment, cervicals in lateral view, distal
femur....). I think it's pretty well described altogether.
Mickey Mortimer
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