[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Introducing: Sinovenator changii



Thomas Holtz wrote-

> Enter _Sinovenator changii_, (Meeman Chang's China hunter) based on a
> partial skull and skeleton and a referred skeleton from the lowest part of
> the Yixian Formation.

Already in my matrix, though running it with only the ninety-four revised
cranial characters entered for some taxa (troodontids, ornithomimosaurs,
segnosaurs, enantiornithines; as I've broken up those clades into separate
OTU's) wouldn't give good results at this point.  Odd this thing is even a
troodontid, as it lacks lots of traditional troodontid apomorphies (maxilla
contacts naris, lateral depression in braincase, expanded parashpenoid
rostrum, enlarged serrations on teeth, trochanteric crest, no
fibula-calcaneum contact, fused astragalocalcaneum, arctometatarsus).  All
that seems to be keeping it there are the dentary foramina inside a deep
groove, large number of dentary teeth, no basisphenoid recess, robust
metatarsal IV and a few other characters.

> The analysis includes species-level OTUs, which I won't reproduce entirely
> here.  Although they do not include all the higher level names I will use,
> here is their tree:

Note the suspicious lack of Microraptor.  It was present in the tree Hwang
et al. presented at SVP, which also had Sinovenator.  Presumedly based on
the same matrix, the SVP tree also had a polytomy between Sinornithoides,
Byronosaurus, Sinovenator, Saurornithoides + Troodon and dromaeosaurs.  So
Troodontidae wasn't neccessarily monophyletic.  Is this the effect
Microraptor has on the tree?  Certainly, they kept it out of the Sinovenator
matrix so as not to divulge the new information discovered about it (damn
them ;-) ).

> Troodontids are almost certainly deinonychosaurs.

I never got them as deinonychosaurs in any of my trees.  Often sister to
Eumaniraptora, sometimes even avialans, but never deinonychosaurs.  I'll
just have to see what my new improved matrix says in.... perhaps April.

David Majanovic wrote-

> You think (in your next post) that's a possible synapomorphy of
Metornithes?
> Despite *Patagonykus* with its vertical pubes?

I'd say Patagonykus' pelvis is opisthopubic, not as much as mononykines,
therizinosaurids or dromaeosaurids, but only slightly less than Sinovenator,
and certainly more than Unenlagia and Rahonavis.

> What were the OTUs in Avialae? Only *Archaeopteryx*, as I fear?

Archaeopteryx, Rahonavis and Confuciusornis.  Full tree is-

|--Allosaurus
`--+--+--Gorgosaurus
   |  `--Tyrannosaurus
   `--+--+--Pelecanimimus
      |  |--Harpymimus
      |  |--Garudimimus
      |  `--+--Struthiomimus
      |     `--Gallimimus
      `--+--Ornitholestes
         `--+--+--Alvarezsaurus
            |  `--+--Patagonykus
            |     `--+--Mononykus
            |        `--Shuvuuia
            `--+--+--+--Alxasaurus
               |  |  |--Erlikosaurus
               |  |  `--Segnosaurus
               |  `--+--Avimimus
               |     |--Caudipteryx
               |     |--Microvenator
               |     |--Chirostenotes
               |     `--+--Oviraptor philoceratops
               |        |--Oviraptor? mongoliensis
               |        |--Citipati? sp. (GI 100/42)
               |        |--Conchoraptor
               |        `--Ingenia
               `--+--+--Rahonavis
                  |  |--Archaeopteryx
                  |  `--Confuciusornis
                  `--+--+--Sinovenator
                     |  `--+--Sinornithoides
                     |     |--Byronosaurus
                     |     `--+--Troodon
                     |        `--+--Saurornithoides mongoliensis
                     |           `--Saurornithoides junior
                     `--+--Sinornithosaurus
                        `--+--Unenlagia
                           |--"Ichabodcraniosaurus" (GI 100/1015)
                           |--Velociraptor
                           |--Saurornitholestes
                           |--Deinonychus
                           |--Utahraptor
                           |--Achillobator
                           |--Adasaurus
                           `--Dromaeosaurus

They used Albertosaurus instead of Gorgosaurus for G. libratus (possible,
but not shown conclusively yet, as far as I know).  Also, they just used
specimen names for Citiapti? sp. and "Ichabodcraniosaurus".

Mickey Mortimer