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Re: Iberomesornis questions



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