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Re: New Jeholornis specimen



> Zhonghe Zhou and Fucheng Zhang:
> Jeholornis compared to Archaeopteryx, with a new understanding of the
> earliest avian evolution

Some interesting new information from the paper-
Two new juvenile specimens from the Jiufotang Formation (IVPP V13553, IVPP
V13550), the former complete and the latter lacking pectoral and forelimb
material.
They confirm the absence of premaxillary and maxillary teeth, but one has a
couple dentary teeth.
There are 14 dorsal vertebrae, some with pleurocoels.
Sapeornis has seven sacral vertebrae, while Jeholornis has six.
The holotype has an incomplete tail, new specimens have complete tails with
24-27 vertebrae.
The sternal plates are unfused, which is probably also the case in
Archaeopteryx (cited as Wellnhofer, pers. comm.).
The posterolateral processes are unfused to the sternal plates.
The scapula is squared off distally, not tapered as originally reported.
The coracoid foramen is medially displaced as in enantiornithines and
Apsaravis.
One specimen has a free distal tarsal, perhaps ontogenetic.
The hallux is reversed as preserved.
Remiges are asymmetrical and retrices are arranged in a distal fan.

Mickey Mortimer