Re: Enigmosaur questions

["Jaime A. Headden" <qilongia@yahoo.com>]

Nicholas Gardner (n_gardner637@hotmail.com) wrote:

<How much material is known for *Caenagnathasia*?  What is the ref for
this taxon?  How long was this oviraptorosaur?  And are there any quality 
reconstructions or photographs of the material?>

  Okies, some of my fave dinos:

  Currie, P.J.; Godfrey, S.J.; & Nessov, L.[A.] 1994 [ref pub'd as 1993].
New caenagnathid (Dinosauria: Theropoda) specimens from the Upper
Cretaceous of North America and Asia. _Canadian Journal of Earth Sciences
- Revue Canadienne du Sciences de la Terre_ 30: 2255-2272.

  *Caenagnathasia martinsoni*
  hypodigm:
    holotype: CMGP 401/12457, fused dentaries with complete symphysis,
      right dentary ramus more complete than left and extending only
      somewhat further caudally than the posterior edge of the symphysis.
    referred: CMGP 402/12457, right dentary with slighyl broken region of
      the symphysis and missing posteroventral ramus (below the external
      mandibular fenestra). This is slightly smaller than the relative
      area of the holotype, and should have been indicated at a paratype,
      but this is not Currie's style [he doesn't use paratypes].

<How much material is known for *Elmisaurus*?>

  Actually, quite a bit -- of one part of the body. It's mostly feet,
which can be exemplified by the name, "foot lizard." I think Halszka
Osmólska was precognitive in this regard.

  *Elmisaurus*
  *E. rarus* (type species by designation) Osmólska, 1981
  hypodigm:
    holotype: ZPAL MgD-I/172, left tarsometatarsus, lacking metatarsals I
      or V.
    referred: ZPAL MgD-I/20, proximal right tarsometatarsus, lacking
      metatarsal V, and with metatarsal III much less complete than II or
      IV.
      ZPAL MgD-I/98, distal metatarsals II-IV, metatarsal I, and pedal
      phalanges pdI-1, II-1--2, III-1--2, proximal III-3, two partial pdIV
      phalanges, two pedal unguals; right manus lacking carpals, proximal
      1/5(?) of metacarpal II, and proximal half(?) of metacarpal III,
      having manual phalanges  mdI-1, II-1--2, and III-1--3, and a large
      manual ungual which may correspond to digit I on the basis of
      articular joint shape, with the proximal portion of another
      (described but not figured) digit.
  *E. elegans*
    holotype: ROM 781, complete left metatarsals II and IV, proximal 1/7th
      and distal 1/3rd of mtIII, along with partial distal tarsals III and
      IV.
    referred: ROM 37163, distal end of metatarsal II.
      RTMP 82.39.4, right tarsometatarsus lacking distal ends below fused
      area, with the second metatarsal extending further distally.
      MOR 752, fragment of the astragalus, a partial metatarsal fragment,
      and most of the metatarsal II with the proximal half of the medial
      surface missing, and pedal phalanges pdII-1 (distal half), pdII-2,
      pdIII-1--4, pdIV-1--3, distal end of pdIV-4, and all of pdIV-5.

<What taxa preserved fused premaxillaries?  I had heard of this as an 
oviraptorosaur or enigmosaur synapomorphy...but apparently it was absent
in some oviraptorids...>

  Depends. The really only exception is *Citipati*, in which the ventral
end of the premaxillae is not fused, but the dorsal part is.
*Conchoraptor*, *Khaan*, *Oviraptor*, GI SPS 100/42, some undescribed
skulls, and *Erlikosaurus* have fused premaxillae. *Caudipteryx* has been
posited as a basal oviraptorosaur, and lacks fused premaxillae. In fact,
the morphology of these agree in only two features between other taxa
referred to as "Enigmosauria" by Naish and Martill: 1) the posterior edge
forms a tomial edge in common with *Erlikosaurus* and oviraptorids (this
is one of Mickey Mortimer's characters), though the presence of teeth
suggests this is convergent, and 2) the ventral edge forms a denticulate
pattern of "tines", as in oviraptorids, but this is not found in
*Erlikosaurus* and is unknown in any described caenagnathid specimen.

<Is there another segnosaur w/ integument impression coming out of China 
soon?  I recall Dr. Holtz mentioning something to this earlier in the
year.>

  Err ... not described, and as for what Tom was talking about ... "wait
for the paper..." :)

<How long were *Beipiaosaurus*, *Alxasaurus*, *Neimongosaurus*, 
*Nothronychus*, and the other segnosaurs?>

  *Beipiaosaurus* may have been a subadult due to unfused neurocentral
sutures, but would have measured around 2ft at the hip, and between 8-10
feet (longest if the tail was longer than typical segnosaurs, but 8 is the
conservative measure).

  *Alxasaurus* measures around 16 feet according to Russell and Dong,
1994, and the specimen's vertebral column is not complete distally, but
appears to be about right. It would have stood about 3.5 feet at the hip.
*Nothronychus* was similar in heft, short at the hip, about 3.4 feet.

  *Neimongosaurus* and *Erliansaurus* seem to be light animals, about 12
feet in length, standing a meter at the hip.

  *Nanshiungosaurus* was a larger animal, the vertebral column before tyhe
tail measuring 15 feet and the tail adding about 10 more feet, giving a
conservative length of 25 feet. It was the second largest segnosaur known,
with the Bayn Shireh taxa (*Segnosaurus*, *Erlikosaurus*, and
*Enigmosaurus*) each about 15 feet long, and probably about 3.5 feet at
the hip each.

  The largest segnosaur is undoubtedly *Therizinosaurus*, whose forelimb
length of 8 feet (humeral length of about 1.5 feet) suggests a grand total
length of over 35 feet. Any more suggestive length would be horribly
assumptive.

  Cheers,

=====
Jaime A. Headden

  Little steps are often the hardest to take.  We are too used to making leaps 
in the face of adversity, that a simple skip is so hard to do.  We should all 
learn to walk soft, walk small, see the world around us rather than zoom by it.

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