[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
Jaime Headden wrote-
> <1.secondary palate formed from premaxilla & maxilla.Is that
> or Ornithimimid?>
> This exists in various taxa, including Ornithomimosauria (present in
> *Pelecanimimus,* *Garudimimus,* and *Harpymimus* as well as
> *Shuvuuia*, and in oviraptorids, but not in *Caudipteryx* apparently, is
> in caenagnathids (as yet).
What's your reference for the presence of this in Pelecanimimus (not visible
in Perez-Moreno et al., 1994) and Harpymimus (privately sent photos I
gather?), and for the absence in Caudipteryx (where the palatal shelf is
unexposed)? Caenagnathids have this (Sues, 1997).
> <2.ulna bowed posteriorly. Maniraptoran or Maniraptoriformes?>
> This occurs in possible non-maniraptoriforms like *Ornitholestes* and
> *Coelurus,* so it is likely this is not a "maniraptoriform" or
> character unless the taxa above are also maniraptoriform.
> appears to have a minute version of this, but *Compsognathus* would seem
> hav it.
Reference for Ornitholestes (not apparent in Osborn, 1917, otherwise
unillustrated)? I disagree regarding Sinosauropteryx (Currie and Chen,
> The description of *Ornitholestes* is being worked on by some notables
> AMNH, so we are waiting the answer to this. However, as from the original
> description and personal observation of the mount, posterior dorsal neural
> spines are higher than craniocaudally long, and the epipophyses are not
> elongated at all, as seems to be noted in all small theropods
Makovicky (1995) indicates Ornitholestes does have anterior cervical
epipophyses extending past the postzygopophyses- "In the probable third
cervical, the epipophysis is well developed, extending posterolaterally
beyond the rim of the postzygapophysis."
> <.quadrate slopes anteroventrally, lower jaw is offset antreriorly &
> below the orbit in what Ornithomimosaurians?>
> In *Ornithomimus,* *Struthiomimus,* *Dromeciomiomus,* and *Gallimimus,*
> and also in *Pelecanimimus.* In *Garudimimus* and *Sinornithomimus,*
> not quite, as this region is a lot more vertical, and in *Harpymimus* you
> tell without a quadrate (missing).
I would argue a more conservative coding of "?" for Pelecanimimus, given the
missing quadrate, disarticulated occiput and post-orbital skull, and
possibly broken mid-mandibular area.
> *Sinosauropteryx* and *Compsognathus*, as well as compsognathids from
> have trapezoidal obturator processes, as in *Allosaurus* (even basal
> have the closed obturator, so this is convergent).
Compsognathus has a triangular obturator process (Ostrom, 1978), the Santana
compsognathid has one side with a quadrangular obturator, the other with a
> Tyrannosaurids and nearly all
> ornithomimids have an ischial foot.
Tyrannosaurids lack an ischial foot.
> Some coelurosaurs have short ascending processes of the astragalus, from
> than 1/5 in *Beipiaosaurus* and therizinosauroids.
Beipiaosaurus has an ascending process of unknown height, as it disappears
underneath the tibia (Xu et al., 1999). Segnosaurs' ascending processes are
still higher than carnosaurs (excepting Fukuiraptor and "Allosaurus"
> Oviraptorosaurs and
> therizinosauroids have most caudals with transverse processes, and
> has many more caudals than 15 with processes.
The only segnosaur that can be coded for this is Alxasaurus, which has only
13 caudals with transverse processes (Russell and Dong, 1993). Caudipteryx
also has a low number (~12-15), as you later corrected. Shuvuuia has 11
caudals with transverse processes (Sereno, 2001).
> 6 sacrals (or more) are only found
> in ornithomimids like *Gallimimus,* oviraptorids where known, troodontids,
> *Ornithodesmus,* *Confuciusornis* and higher birds, and tyrannosaurids.
Sinovenator has only five sacrals (Xu et al., 2002), as do tyrannosaurids
(Makovicky, 1995). Other taxa with over five sacrals include some
segnosaurs, Chirostenotes, some dromaeosaurs, some non-pygostylian avians,
Avimimus, alvarezsaurids and (depending on how you define "sacral")
> Some coelurosaurs lack the condition
> or extensively overlapping caudal prezygapophyses, including the
> + therizinosauroid clade, birds including *Archaeopteryx,*
Caudipteryx and Nomingia still have some elongate (>40% of central length)
And some answers to other things Steven Mahon wrote, that I feel I can add
> 2.ulna bowed posteriorly. Maniraptoran or
Maniraptora, as it's lacking in ornithomimosaurs (Deinocheirus,
Archaeornithomimus, Ornithomimidae) and mononykines. But also known in a
couple basal taxa (Coelurus, Scipionyx), and missing in several
maniraptorans (eg. some segnosaurs, Caudipteryx, Noguerornis).
> 3.does Troodontidae havethe Eumaniraptoran characters
> from my previous thread?
Sinovenator has an opisthopubic pelvis (not in Sinornithoides,
Saurornithoides or Troodon), Sinovenator and Troodon have a laterally facing
glenoid (not in Sinornithoides), and Sinovenator has the derved coracoid
shape. Sinornithoides seems to lack an ossified sternum and sternal ribs,
and whether any had a furcula is unknown.
> 4.are the Alvarezsaurid-Archaeopteryx characters (from
> the previous thread) found in any of the forms above?
Excepting alvarezsaurids and Archaeopteryx....
57.tympanic recess opens within columellar recess (not
-- Sinovenator, Troodon and I assume Passer.
58.teeth w/ unserrated crowns
-- If you mean all teeth, then Pelecanimimus and Caudipteryx.
59.caudal count less than 25-26
-- Not found in alvarezsaurids, also in Caudipteryx, Confuciusornis and
60.short, reduced caudal zygapophyses
-- Compsognathus, Sinosauropteryx, Coelurus, Alxasaurus, presumably
Khaan(?), Sinovenator, presumably Passer.
> 5.Does Sinornithosaurus have the Dromaeosaurid
66.T-shaped lacrimal, Y-shaped quadratojugal
-- Yes, yes.
67.neural spines of neck vertebrae large& erect
68.5 sacral vertebrae
-- Yes, but primitive.
69.tendon-like extensions of tail zygapophyses,
70.paired sternal plates
-- Yes, but primitive.
71.pubis faces down & backward to parallel ischium
-- As much as in most dromaeosaurids.
72.digit I pes reversed, parallel to other toes
-- Not found in dromaeosaurids.
73.distal articulation of metatarsal II & III
-- moderately developed on mtII, not on mtIII.
>> Well, therizinosauroids and some birds have very
>> short ascending processes;
> Do you mean Alxasaurus & Beipaosaurus have it too? Or
> is it unknown in those? Is it in Confuciusornis?
Can't tell in Confuuciusornis due to fusion, unknown in Beipiaosaurus and
- From: Steven Mahon <firstname.lastname@example.org>
- Re: Questions
- From: "Jaime Headden" <email@example.com>