Tenth Archaeopteryx and microraptorian pygostylians

[Michael Mortimer <mickey_mortimer111@msn.com>]

Well, this specimen was unexpected.  I never doubted the promaxillary and 
maxillary fenestrae.  Elzanowski always seemed way too cautious about 
homologizing with theropods (like the dorsal jugal process not being 
homologous with dromaeosaurs'). The jugal process on the palatine eliminates 
one of the characters more birdy than dromaeosaurs that Archaeopteryx was 
supposed to have.  The lack of a reversed hallux was established by 
Middleton earlier.  I agreed with Paul (2002) about its hyperextendable 
second pedal digit.  And of course, not many of us doubted it had an 
astragalar ascending process (nice to see another nail in the BAND coffin, 
assuming there's any wood left to drive them in to).  This specimen also 
proves the premaxillae were unfused, making Elzanowski's caution about this 
moot.

I found their new topology interesting (discovered after changing eight 
codings for Archaeopteryx, and one for Rahonavis)-
|==other taxa
`--+--+--Archaeopteryx
  |  `--Rahonavis
  `--+--Troodontidae
     `--+--+--Confuciusornis
        |  `--Microraptor
        `--+--Sinornithosaurus
           `--Dromaeosauridae (incl. Unenlagia)
Remind anyone of my last topology, where pygostylians were sister to 
dromaeosaurs, while Archaeopteryx and Rahonavis were troodontids?  Not 
exactly the same, but with some common trends away from the standard 
topology.

You're all probably wondering what happens when the changes are made to the 
Buitreraptor matrix.  The Archaeopteryx matrix is based on an older version 
of the TWG study (Hwang et al.'s 2002 Microraptor paper), without four 
ornithomimosaurs, compsognathids, Incisivosaurus, Mei, IGM 100/44, 
Neuquenraptror or of course, Buitreraptor.  When the changes are made to my 
corrected Buitreraptor matrix (see my earlier post for details), I get the 
same result as before, except Archaeopteryx is now outside Rahonavis + 
Confuciusornis-
|--+--Adasaurus
|  |--Achillobator
|  |--Utahraptor
|  |--Dromaeosaurus
|  |--Saurornitholestes
|  |--IGM 100/1015
|  `--+--Velociraptor
|     `--Deinonychus
`--+--Sinornithosaurus
 |--Microraptor
 `--+--+--Buitreraptor
    |  |--Unenlagia+Neuquenraptor
    |  `--+--Archaeopteryx
    |     `--+--Rahonavis
    |        `--Confuciusornis
    `--+--+--Mei
       |  `--Sinovenator
       `--+--Sinornithoides
          `--+--Byronosaurus
             `--+--Troodon
                `--+--Saurornithoides mongoliensis
                   `--Saurornithoides junior

But separate Unenlagia from Neuquenraptor, and you get-
|==other taxa
`--+--+--Archaeopteryx
  |  `--+--Rahonavis
  |     |--Unenlagia
  |     `--Confuciusornis
  `--+--Troodontidae
     `--+--Buitreraptor
        `--+--+--Microraptor
           |  `--Sinornithosaurus
           `--+--Velociraptorinae
              `--Dromaeosaurinae
Neuquenraptor is closer to dromaeosaurs than troodontids, but is not a 
dromaeosaurid sensu stricto (Dromaeosaurinae + Velociraptorinae).  This is 
actually the same as the original Buitreraptor matrix, except Rahonavis and 
Unenlagia are birds instead of sister to Buitreraptor.  And besides 
Unenlagia being a bird, the result is the same as the standard TWG trees.  
Odd how combining Unenlagia and Neuquenraptor was so harmless in Makovicky 
et al.'s original matrix (actually leading to a 'logical' result of a 
Gondwanan dromaeosaur clade), but completely changes paravian topology when 
the matrix is corrected (leading to strange things like 
non-deinonychosaurian microraptorians).

Archaeopteryx is still a bird in the analysis based on 22 characters- 
asymmetrical remiges; posterior tympanic recess opens in otic recess; 
separate parietals; transition point proximal to sixth caudal vertebra; less 
than 25 caudal vertebrae; no proximodorsal lips on manual unguals; elongate 
preacetabular process; supracetabular shelf present; lateral edge of 
cuppedicus fossa extends far posteriorly; pubic symphysis reduced in length; 
distal tarsals fused to metatarsals; metatarsal IV transversely broad in 
section; postacetabular process concave dorsally; large proximodorsal 
ischial process; mid-dorsal ischial process; elongate ulnofemoral ratio.  
Examination of the matrix shows Sinornithosaurus and Microraptor both scored 
incorrectly as lacking asymmetrical remiges (should be ? and 1 
respectively).  Pelecanimimus, Chirostenotes and troodontids were scored 
incorrectly for the posterior tympanic recess.  Sinraptor, Allosaurus, 
Compsognathus, Caudipteryx and Rinchenia for parietal fusion.  
Ornitholestes, Huaxiagnathus, Harpymimus, Alxasaurus, Conchoraptor, Ingenia 
and Microraptor for caudal number.  Sinraptor, Sinosauropteryx, 
Compsognathus, Harpymimus, Archaeornithomimus, Patagonykus, Caudipteryx, 
Oviraptor, Sinornithoides, Sinornithosaurus, Achillobator, Archaeopteryx and 
Confuciusornis for manual ungual lips.  Garudimimus, Archaeornithomimus, 
Alxasaurus, Segnosaurus, Chirostenotes, Sinovenator, Saurornitholestes, 
Deinonychus and Adasaurus for preacetabular length.  Gorgosaurus, 
Tyrannosaurus, Garudimimus, Caudipteryx, Microvenator and Rinchenia for 
supracetabular shelf size.  I have yet to check all taxa for the last eight 
characters, so more corrections are probably necessary.  After these 
corrections, the resulting tree is-
|--+--Adasaurus
|  |--Achillobator
|  |--Utahraptor
|  |--Dromaeosaurus
|  |--Saurornitholestes
|  |--IGM 100/1015
|  `--+--Velociraptor
|     `--Deinonychus
`--+--Sinornithosaurus
  |--Microraptor
  `--+--+--Buitreraptor
     |  |*-Unenlagia
     |  `--+--Archaeopteryx
     |     |--Rahonavis
     |     `--Confuciusornis
     `--+--+--Mei
        |  `--Sinovenator
        `--+--Sinornithoides
           `--+--Byronosaurus
              `--+--Troodon
                 `--+--Saurornithoides mongoliensis
                    `--Saurornithoides junior
Unenlagia can go anywhere in the Buitreraptor + Aves sensu Chiappe clade.  
Neuquenraptor is an avialan outside Troodontidae (just for completion's 
sake, if Unenlagia and Neuquenraptor are combined now that the codings are 
more accurate, the same tree results, except that Unenlagia+Neuquenraptor is 
definitely outside Aves, in a trichotomy with it and Buitreraptor).  In this 
tree, Archaeopteryx is a bird based on- separate parietals; lateral dentary 
foramina not inside groove; splenial not broadly exposed laterally; less 
than 25 caudal vertebrae; anterior surface of deltopectoral crest smooth; 
elongate preacetabular process (in Unenlagia too); lateral edge of 
cuppedicus fossa extends far posteriorly (in Unenlagia too); pubic symphysis 
reduced in length; no contact between midlength portion of pubic apron (in 
Unenlagia too; correlated with prior character?);  large proximodorsal 
ischial process (in Unenlagia too); non-arctometatarsalian metatarsus; 
large, longitudinal flange along caudal or lateral face of metatarsal IV 
absent; mid-dorsal ischial process; elongate ulnofemoral ratio.  The 
Buitreraptor + Aves clade is diagnosed by- serrationless teeth; 
supracetabular shelf present; mesopuby; postacetabular process concave 
dorsally.

So contra Mayr et al. (2005), there are "significant derived characters that 
are exclusively shared by Archaeopteryx and more typical avians such as 
Confuciusornis but are absent in basal deinonychosaurs such as Microraptor." 
 This isn't to say I don't think their phylogenetic conclusions are 
plausible (except placing Confuciusornis closer to Microraptor than 
Sinornithosaurus is).  And I agree with their broad conclusion 
deinonychosaurs may be avians sensu Chiappe.  I'm glad they reference Paul 
for that idea instead of MANIAC's too.  How will this new specimen affect my 
analysis?  That will be interesting to find out.

Mickey Mortimer