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"Chuniaoae" Ji et al. 1998



I hope this doesn't come through twice, I tried sending it once, and it wouldn't send for whatever reason, so just in case it had sent anyway and it just wasn't telling my browser that it was time to go to the next page, I waited about 5-6 minutes but it didn't come in, so I'm resending it.


I was printing off the supplementary information for Ji et al. 1998, and noticed that there were diagnoses for two clades -- "Chuniaoae" and Avialae. "Chuniaoae" is not mentioned after that point and appears to be used for the unnamed clade of _Caudipteryx_ + Avialae further down in the text. I suppose this could be the earliest name for the clade containing both paravians and enigmosaurians. I looked it up in the DML archives and noticed that it has not been mentioned once. However, Chuniaoia (Ji & Ji 2002) is used at one point, but it's for a clade including _Protarchaeopteryx_ but not the avialans. Mickey Mortimer pointed out (or at least implied) that if _Protarchaeopteryx_ is an enigmosaur, then the clade containing enigmosaurs and paravians would be Dromavialae (Ji & Ji 2002).


"Chuniaoae" Ji et al. 1998

Etymology:

Uhm... heck if I know. Something "wings", I figure. But I bet it means something that sounds better than Dromavialae, which could mean... what? "Dromaeosaurs & Avialans"? Or perhaps "Running Bird Wings"?

Content:

In Ji et al. (1998)'s analysis, "Chuniaoae" consists of _Caudipteryx_ and the Avialae, which in turn, includes _Archaeopteryx_, _Mononykus_, _Shuvuuia_, Enantiornithes, and Ornithurae. The latter four are united together, and then _Mononykus_ and _Shuvuuia_ are united together and the Enantiornithes and Ornithurae are united together. The sistergroups are Velociraptorinae (presumedly including _Deinonychus_, _Velociraptor_, and _Saurornitholestes_; this is because their analysis is the modified from Chiappe et al. 1998 which only cites Currie 1995 as far as dromaeosaurid references go) and _Protarchaeopteryx_.

Definition:
?_Caudipteryx_ + Avialae (Gauthier 1986). Evidentally, the authors were not using Padian (1997)'s definition of Avialae which is Neornithes <-- _Deinonychus_. If they had, the clade would have included _Protarchaeopteryx_ and _Caudipteryx_. I think that this clade, if used in the future, might be better defined as _Caudipteryx_ + Neornithes, or _Caudipteryx_ + _Archaeopteryx_ + Neornithes, preferably the latter, because attempts to apply it to most current analyses would find it to be the Enigmosauria + Eumaniraptora clade and even if in future analyses, the Enigmosauria was found closer to Neornithes than _Archaeopteryx_, the content would be more stable as opposed to defining it with the former definition, in which _Archaeopteryx_ would be ejected from "Chuniaoae" unlike in Ji et al. 1998 where it is a member of the clade. Of course, alvarezsaurids are in the "Chuniaoae" according to Ji et al. 1998, but in most current analyses (by the AMNH team), these are found outside of the Enigmosauria + Paraves clade. However, I suppose a third definition might be feasible of _Caudipteryx_ + _Archaeopteryx_ + _Shuvuuia_ + Neornithes because that would be closest to the original content of Ji et al. 1998, however, that's four anchor taxa, which is alot and sort of messy, because alvarezsaurids like to jump around, and if Sereno and Martin are correct, they could be ornithomimosaurs, in which case "Chuniaoae" would be the same as Maniraptoriformes which has priority, so it might be better just to go with the other two proposed definitions.


Diagnosis:
According to the supplementary information, there are two unambigious synapomorphies of this clade: frontal process of premaxilla relatively long, at least approaching the rostral border of the antorbital fossa & teeth with unserrated crowns in adults. However, in the text, the clade is diagnosed by: short tail composed of less than 23 caudal vertebrae & arms with remiges attached to manual digit II. It's fairly obvious that in most published analyses, this diagnosis would not be accurate. If "Chuniaoae" was used to define the Enigmosauria + Paraves clade, then according to Norell et al. 2001, it would be diagnosed by: ossified sternal ribs; sternum with lateral xiphoid processes; articular facet for coracoids on sternum placed almost anterior; coracoid in lateral view subquadrangular with extensive ventral blade; glenoid fossa faces laterally; and posterior trochanter distinctly raised from shaft and mound-like.



If you made it to this little sentence here, you can be thankful because I am done with this post and there isn't anymore boring stuff to read. ;-D


Best regards to all,

Nick Gardner

P.S. I lied, there's more boring stuff, the references are down there. Now I must run and go finish watching M*A*S*H before the DVD burns up in the player, what will happen when Big Mac comes to visit? I'm nearly to the end, I should have finished watching before I started writing, I took 45 minutes longer to write this than expected. :-)

References-

Chiappe, Norell, & Clark (1998). The skull of a relative of the stem-group bird _Mononykus_. Nature 392: 275-278

Ji, Currie, Norell, & Ji (1998). Two feathered dinosaurs from northeastern China. Nature 395: 753-761

Keesey (2002). Ji and Ji's Classification. Public post to the Dinosaur Mailing List on 12 Feb 2002- http://www.cmnh.org/dinoarch/2002Feb/msg00463.html

Mortimer (2002). Re: Ji and Ji's Classification. Public post to the Dinosaur Mailing List on 13 Feb 2002-
http://www.cmnh.org/dinoarch/2002Feb/msg00476.html


Norell, Clark, & Makovicky (2001). Phylogenetic relationships among coelurosaurian theropods. In Gauthier & Gall, eds. New Perspectives on the Origin and Early Evolution of Birds: Proceedings of the International Symposium in Honor of John H. Ostrom. New Haven: Peabody Mus. Nat. Hist. Yale Univ.

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