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Better late than never.....
Rutger Jansma wrote-
> 1) Ginnareemimus is reported to have an almost
"arctometatarsalian" pes, like in Sinovenator, > but how does this relate in terms of their relationships, are they
closely related or does this
> mean the arctometatarsalian pes can be achieved by convergence leaving it as practicly
> meaningless in phyletics?
And Tom Holtz replied-
>> A) The Thai
ornithomimosaur actually has a metatarsus which is closer in form to
>>
ornithomimids proper than is Garudimimus. Sinovenator's
pes, on the other hand, is non-
>>
arctometatarsalian.
I thought
Garudimimus' metatarsus was fully arctometatarsal, as much as Elmisaurus or
Ornithomimus velox at least. Isn't it the one illustrated as Oviraptor in
Currie and Russell (1988)?
Actually,
"Ginnareemimus'" and Sinovenator's metatarsi look amazingly similar.
Sinovenator is a bit less arctometatarsal, with mtIV more robust, mtII more
reduced distally, mtII and IV shorter, and mtIII having a ginglymoid distal
articulation. In proximal view, they are not too similar. Not to try
to resurrect Bullatosauria or anything, but maybe "Ginnareemimus" is closer to
basal troodontids than ornithomimosaurs. I've still seen no evidence it is
an ornithomimosaur after all. What do others think? I can send a
scan of "Ginnareemimus'" metatarsus if needed.
> 3) Again
on Archaeornithomimus and the supposed synonymy to Garudamimus, what are the
> shared characteristics between
the two apart from shape of the pubis and are there any
> differences between them? The femur for instance is practicly straight in A.
while it is curved > in G. and the crest on the tibia (damn' names...) on it's proximal end is less pronounced in A. >
compared to G., but there are more right?
They're hard to compare.
Archaeornithomimus has- shorter dorsal neural
spines; shorter caudal neural spines; wider pubic peduncle on ilium; lower
ilium; longer postacetabular process; more massive pubic boot; longer posterior
pubic boot; less prominent cnemial crest; metatarsals III and II curved
medially; narrower metatarsal III; metatarsal II longer than IV; straighter
pedal unguals.
Further comparison is difficult because they are
both incompletely known and Garudimimus is poorly described.
> 4) Is Confuciusornis dui still considered a
valid species of Confuciusornis?
C. dui can be distinguished from illustrated C.
sanctus specimens by- narrow and tapered ascending process of maxilla without
maxillary fenestra; maxilla takes up most of ventral orbital margin; low rounded
dorsal jugal process?; jugal forms ventral margin of laterotemporal fenestra?;
mandible without anteroventral expansion;
posterodorsal dentary process extends posteriorly over most of mandibular
fenestra; posterodorsal dentary process taller than posteroventral process; no
ventral surangular process invading mandibular fenestra; reduced surangular
foramen; sternum with anterior notch; sternal ribs attach to lateral processes;
sternal lateral processes not bifurcate; four sternal ribs; sternal ribs grow
posteriorly shorter; last two sternal ribs markedly expanded distally;
metacarpal I tapers proximally; manual unguals I and III subequal in size.
Characters with a question mark after tham are
only verifiable in one figured specimen of C. sanctus. They seem quite
distinctive to me, and I see no reason to doubt the validity of C. dui. At
least six of the characters are absent in C. sanctus specimen GMV-2131,
which is smaller than C. dui, so ontogeny is ruled out. The latter
specimen also has tail streamers, so sexual variation is similarily ruled
out.
> 9) In DA HP Greg Paul states that
Eoenanthiornis could be a juvenile or subadult genus, is
> this correct?
Perhaps. The sternum is a nice intermediate
between juvenile Liaoxiornis and adult enantiornithines.
However, Eoenantiornis is about equal or larger in size than other Yixian
enantiornithines, so it would have to be an unknown larger taxon. Also,
the craniofemoral ratio is lower than Sinornis and most other Yixian
enantiornithines, very different from the situation in Liaoxiornis. There
is no indication of unfused structures that should be fused. I don't think
the orbit is unusually large and see no indication for a "poorly formed
hand". But I've not seen a good photo of the specimen.
Mickey Mortimer
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