Clarifications of Paul's new DA taxa

[GSP1954@aol.com]

Some comments to clear up some confusion about the new taxa in DA.

As I spend some considerable time explaining in the text, it is important to 
understand that Avepoda, Averostra, Avepectora and Avebrevicauda are 
apomorphy + CLADE labels, which are very distinct from the entirely cladistic 
node taxa that have become the norm, or the old apomorphy taxa of yore. A+C 
taxa could only appear at  phylogentic node if we had all extinct and living 
taxa available and correctly placed, which will never happen, so in practical 
terms A+C taxa never appear at a node in a phylogenetic chart. 

Equally importantly, A+C taxa are always more inclusive than clade node taxa 
that incorporate a key character in the name, which, because we have an 
incomplete fossil record, always leave the basal members of the clade with 
the key character out. For example, any clade node taxa that incorporates all 
known theropods that lack contact between the 1st metatarsal and distal 
tarsals and are in the clade that includes birds inherently excludes more 
basal members that share the character but have not been found yet, or were 
never preserved. Avepoda does include every single such dinosaur and bird. 

This means that A&C names in practical terms are never ever synonymous with 
any clade node taxa. Avepoda can never be the equivalent of Neotheropoda, 
Eutheropoda or anything else. That's one of the beauties of these A+C taxa, 
you can try to drive stakes through their hearts and shoot them with silver 
bullets and it does not matter, they cannot be killed off. This is unlike 
clade node names where if a name is applied to two nodes, and it later turns 
out that the nodes are actually the same, then the junior synonym goes belly 
up, its legs feebly kicking and its only hope being eventual demostration 
that its node is distinct after all. From now on all dinosaurs that lack 
contact between Mt1 and the distal tarsals and belong to the clade that 
includes birds are avepods forever and ever, and no one can do anything about 
it. They finally and will always have the etymologically accurate name they 
deserve.
   
Neotheropoda and Eutheropoda remain valid and are included within Avepoda. 
Note that if a dinosaur is found that lacks contact between Mt1 and the 
distal tarsals but is shown to have evolved this feature separately from the 
clade that has this character and includes birds, then the new dinosaur is 
not an avepod, it is an avepod mimic. Subsequent loss of a character is of 
course not important, so therizinosaurs are still avepods even though they 
were weird enough to recontact Mt1 with the distal tarsals, just as snakes 
remain tetrapods even though they've lost those pods. 

Currently Averostra includes ceratosaurs (which I and other consider not 
allied with coelophysoids) and the rest of avepods closer to birds. 
Dilophosaurus appears to be a coelophysoid that evolved a promaxillary 
fenestra independently of averostrans, so it is an averostran mimic. In the 
less likely event that that Dilophosaurus is closer to the ceratosaur-bird 
clade than coelophysids then it is an averostran. Or, in the unlikely event 
that the Ceratosauria is a monophyletic clade then both ceratosaurs and 
dilophosaurs are probably not averostrans, unless coelophysoids lost the 
extra fenestra. Again, averostra is not the junior synonym of any clade node 
taxon. 

It is important that Avepectora includes averostrans in which the coracoid is 
flexed so strongly relative to the scapula that the outer surface of the 
coracoid faces so strongly anteriorly that it articulates with the sternum at 
an angle of over 45 degrees from the midline - basically the avian system 
also found in the most bird-like dinosaurs. This is not synonymous with, and 
probably includes Maniraptora.  

It is interesting that Maryanska et al. in their new Acta Palaeont Pol paper 
place Oviraptorosaurs (incl avimimids) were even I do not go, in the 
Avebrevicauda above Confuciusornis. Although I agree with the post-urvogel 
neoflightless statues, I doubt this high placement. But if they are correct 
the longer tail of the dinosaurs probably represents a reversal (unless some 
basal birds evolved very short tails independently of a oviraptorosaur-modern 
bird clade), and Avebrevicauda excludes the most basal short tailed birds 
while probably including Ornithothoraces. 

G Paul