|
Rutger Jansma wrote-
> 1) Has there been any hand-material
discovered for this genus? The photographs of the specimen has > the hands
missing, due to preservation or due to fossilisation, I don't know, point is:
they aren't there. > But... L. D. Martin has them reconstructed in his
Iberomesornis-reconstruction from 1995b (The ?
> Enantiornithes: Terrestrial birds of the
Cretaceous in avian evolution. Courier Forschungsinstitut
> Senckenberg, 181: 23- 26). The
reason for this question is that I am doing a reconstruction of this
> genus and it is important to know wether
the hands should be based on a) L. D. Martin's
> reconstruction, b) based on Sinornis (which
is a close relative, based on pelvic similarities) or c)
> something else...
No, no manual material is known. Only the holotype and a
questionably assigned foot. Basing the hand on Sinornis and Concornis
would be a good idea. Phalangeal formula of 2-3-1, with small claws on
digits I and II.
> 2) Feduccia's (sorry for mentioning the
name :)) book says, again based on L. D. Martin's research, that >
Iberomesornis was a juvenile birds, this is certainly possible, mainly due to
it's small size (it was only 8 > cm long), but what are the current estimates
about how long it was when it reached adulthood?
The specimen was probably nearly adult, the only juvenile
features being the first four sacrals are only partially fused and the proximal
caudal vertebrae making up the pygostyle are still separately visible. The
tarsals and metatarsals are well fused though.
> 3) For this little Spanish genus was an
entire new order erected, the so called Iberomesornithiformes, is > this
family stil valid in light of the possibility that it could be a juvenile birds
(reasons for doubt: other > thread) ? And if so, are there any new genera
included herein and on what characters is this order
> funded?
Whole orders have been made for so many Mesozoic birds (Yandangithiformes Cai and Zhou 1999, Confuciusornithiformes Hou et al.
1995, Longipterygiformes Zhang et al. 2001, Gobipterygiformes
Elzanowski 1974, Alexornithiformes Brodkorb 1976, Enantiornithiformes Martin
1983, Cathayornithiformes Zhou, Jin and Zhang 1992, Sinornithiformes Hou 1997,
Eoenantiornithiformes Hou, Martin, Zhou and Feduccia 1999),
Iberomesornithiformes is no different. According to the one actual good
published study of enantiornithine phylogenetics (Chiappe, 2001), Iberomesornis
and Noguerornis are more closely related to each other than Sinornis,
Gobipteryx, Concornis and Neuquenornis are. The latter group is called
Euenantiornithes by Chiappe et al. 2002, but I don't know what the Iberomesornis
+ Noguerornis clade is named. Iberomesornithiformes might be a good
choice. It might be noted that in Chiappe 2001, this clade was only
diagnosed by the absence of procoelous sacral vertebrae (reversal). This
also reverses in ornithurines anyway, and is unknown in any included
euenantiornithines except Sinornis according to Chiappe's matrix. Further
research indicates Gobipteryx also had it, but Changchengornis lacks it.
All of this shows the clade is very unstable. So no, there is no evidence
an Iberomesornithiformes is needed, or that we know of any other taxa that could
be included in it. Chiappe's enantiornithine chapter in the perpetually
upcoming Mesozoic Birds book should be quite enlightening, including a
phylogenetic analysis with 16 euenantiornithine taxa.
Mickey Mortimer
|