Re: smallest and largest Jurassic theropods

[Mickey Mortimer <Mickey_Mortimer111@msn.com>]

Jaime Headden wrote-

> Mickey Mortimer (Mickey_Mortimer111@msn.com) wrote:
>
> <Archaeopteryx lithographica Meyer 1861
> (JM 2257; Eichstatt- 5th; holotype of Archaeopteryx recurva)>
>
>   *Archaeopteryx* only works if the adult is smaller.

Octavio asked "what are the two smallest and the two largest theropod
specimens in Jurassic?".  Specimens, not species.  If you try to specify
species, the question is basically hopeless, since dinosaurs had
indeterminate growth and young adults would be smaller than old adults
anyway.

> Otherwise, I would beleive the
> Lower Jurassic *Coelophysis* juveniles or the Portuguese theropod embryo
> referred to *Lourinhanosaurus* would be the winners, along with the
> possible juvenile (undeveloped epiphyses of long bones, for example)
> *Epidendrosaurus.* The possibly synonymous and coeval *Scansoriopteryx* is
> only a slight bit larger than *Epidendrosaurus.*

Scansoriopteryx MAY be coeval with Epidendrosaurus, but this is based on
Czerkas' unpublished statement for now.  It would nicely explain why they
are so similar, however.

> <Lukousaurus yini Young 1948>
>
>   Mickey himself has suggested, along with others, that this is a
> sphenosuchian:
>   http://www.cmnh.org/dinoarch/2000Sep/msg00086.html
>   also,
>   http://www.cmnh.org/dinoarch/2002Apr/msg00241.html
>   in which I listed citations to people who have looked at the material
> and concluded likewise or implied so.

I suggested it was abelisaurid or sphenosuchian, actually.  Resembles both,
though stratigraphy would favor the latter.  I've not seen a review of this
taxon in the recent literature, casual and ambiguous dismissals (such as in
The Dinosauria) notwithstanding.  If you can provide a reference for your
vague and uncertain citation to Clark's or Rauhut's opinion of it, I would
be grateful.

> <Podokesaurus holyokensis Talbot 1911>
>
>   Likely a juvenile *Coelophysis,* the epiphyses are hardly developed and
> badly damaged prior to the destruction of the fossils, as determined by
> the numerous casts that have replaced it.
>
>   Colbert, E.H. 1964. The Triassic dinosaur genera *Podokesaurus* and
> *Coelophysis.* _American Museum Novitates_ 2168: 1-12.

Perhaps.  I'd like to know if it could be distinguished from
Procompsognathus or Segisaurus before I synonymize it with Coelophysis.
Colbert (1964) did find two characters which it differed from Coelophysis
bauri in, but a modern review is desperately needed to determine the amount
of variation within the Ghost Ranch specimens.  These coelophysids are a
mess right now.

> <Borsti
>   Material- (Eichstätter Jura-Museum coll.) (juv.) skull (76 mm), anterior
> cervical vertebrae, more?>
>
>   A good deal larger than even *Compsognathus,* so peculiar to include
> this here.

Borsti's skull is ~76 mm, the holotype Compsognathus' skull is ~75 mm.  A
good deal indeed....

Mickey Mortimer
Undergraduate, Earth and Space Sciences
University of Washington
The Theropod Database - http://students.washington.edu/eoraptor/Home.html