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Re: Archie skull pneumatics?
Nick Gardner wrote-
> This is becoming frustrating to follow. According to an earlier post,
> were not preserved with *Scansoriopteryx*. Now we're talking about how it
> had serrationless teeth?
Jaime explained it well enough. I see little reason to separate the taxa,
the only notable differences being that Scansoriopteryx's holotype has-
- frontal lateral edge less concave
- sclerotic ring formed of separate elements
- distal scapular edge perpendicular to the blade axis
- ulna not bowed
- smaller manual ungual I (55% of mcII vs. 79%)
- shorter manual digit III (compared to digit II)
- metatarsal IV subequal to II
Perhaps they are different species, but they are certainly similar enough to
be in the same genus (using my Holtz brand Genericometer of course). My
choice of names is purely personal of course, as last I heard the verdict
was not in for what was the official publication date of either name. I
don't believe they have to be demonstrably the same age, as Epidendrosaurus'
holotype has no well defined age associated with it in the first place.
Jaime Headden wrote-
> Take the frontals:
> in *Scansoriopteryx* these are preserved both showing the side and top of
> the T-shaped bones, whereas in *Epidendrosaurus* they are side-on, and
> exposed flat, so it is not possible to determine how much distortion is
> present due to flattening. Limb bones have a general comparison, but the
> Czerkas specimen has larger arms, and incomplete hindlimb bones, which
> renders the estimate of limb length a bit on the shaky side.
The frontals are preserved in dorsal/ventral view in both specimens. I'm
frankly confused how one could interpret those in the Scansoriopteryx's
holotype as being "side on", given how left and right elements are
symmetrical as preserved. Czerkas' specimen actually has shorter arms
compared to femoral length, by a whole 5%.
Nick Gardner wrote-
> If such variation occurs in the caudal count for *Archaeopteryx*, is it
> possible that there were more than two species? And whatever happened to
> *Wellnhofferia grandis*?
Caudal counts differing by one or two within a species are the norm for
theropods (eg. Allosaurus, Gallimimus). Wellnhoferia has only fifteen
caudals preserved (contra Jaime's statement of seventeen), and Elzanowski
estimates another couple were originally present, giving a lower vertebral
count than Archaeopteryx.
I'm including Wellnhoferia as a separate OTU in my in progress (but finally
progressing) analysis, along with our new friend Microraptor? gui.