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Re: Yet even more questions (and I'm sure there'll be more...)



Dino Rampage wrote-

> 3) Is there any evidence for mononykines, true Oviraptoridae or
> homalocephalid pachycephalosaurs in Late Cretaceous North America? While
> dromaeosaurids, troodontids, caenagnathids, ornithomimids, tyrannosaurs,
> ankylosaurs, pachycephalosaurids and hadrosaurs seem common to both Asia
and
> America, (and some even seem to share genera) it's puzzling to see some
> groups don't seem to make the journey over the Bering Straits (if they did
> exist then) Alvarezsaurs, therizinosaurs, oviraptorids, homalocephalids,
> nemegtosaurs sauropods from Asia, and "hypsilophodonts", ceratopsids and
> nodosaurs from North America seem unique to their continent.

North American alvarezsaurids-

unnamed Mononykinae (Hutchinson and Chiappe 1998)
late Maastrichtian, Late Cretaceous
Hell Creek Formation, Montana, US
Material- (UCMP 154584) pubis (~100 mm), partial ischium
metatarsal III
Diagnosis- ischium substantially reduced in size compared to pubis.
Description- The third metatarsal is similar to Mononykus, but not as
laterally compressed in the middle and has a sharper plantar ridge.
References- Hutchinson, J.R., and Chiappe, L.M. 1998. The first known
Alvarezsaurid (Theropoda: Aves) from North America. Journal of Vertebrate
Paleontology 18(3):447-450.
Buckley and Ott, 2001. A new specimen of alvarezsaurid from the Late
Cretaceous Hell Creek Formation. JVp 21(3) 36A-37A.

? Parvicursor? minutus (Marsh 1892)
= Ornithomimus minutus Marsh 1892
Late Cretaceous
Colorado, Wyoming, US
Holotype- (lost) partial metatarsals II, III and IV
Referred- (USNM 2909) (.4 m) distal half of metatarsal II, two distal pedal
phalanges
Comments- Russell (1972) considered "Ornithomimus" minutus an indeterminate
dromaeosaurid or pterosaur.
Reference- Russell, 1972. Ostrich dinosaurs of the Late Cretaceous of
Western Canada. Canadian Journal of Earth Sciences. 9 375-402

North American segnosaurs-

undescribed Segnosaurian (Olshevsky pers. comm. 1999)
Early Cretaceous
Utah
Material- includes teeth, ischium, metatarsal I and unguals
Comments- metatarsal I reduced

undescribed Therizinosauroid (Gillette, 2001)
Early Turonian, Late Cretaceous
Tropic Shale, Utah, US
Material- several dorsal vertebrae, dorsal ribs, sacrum, caudal vertebrae,
chevrons, ilia, pubes, ischia, femora (700 mm), tibiae (630 mm), fibulae,
astragali, seven metatarsals (230 mm), ten pedal phalanges
Description- opisthopubic pelvis, tetradactyl pes
Reference- Gillette, 2001. A Late Cretaceous (Early Turonian)
therizinosaurid dinosaur (Therizinosauridae, Theropoda) from the Tropic
Shale of Southern Utah, USA. NAPC 2001 abstracts.
Gillette, Albright, Titus and Graffam, 2001. Discovery and paleogeographic
implications of a therizinosaurid dinosaur from the Turonian (Late
Cretaceous) of Southern Utah. JVP 21(3) 54A.

Nothronychus Kirkland and Wolfe 2001
N. mckinleyi Kirkland and Wolf 2001
mid Turonian, Late Cretaceous
Moreno Hill Formation, New Mexico, US
Holotype- (MSM P2106) incomplete skeleton including cervical vertebra,
pectoral elements, forelimb elements, ischia
Description- Describes the braincase of Nothronychus, which is 79mm across
the paraoocipital processes.  Like Erlikosaurus, the basisphenoid is very
pneumatized, the basipterygoid processes and basitubera are indistinct and
the paraoccipital processes are hollow.  The occipital condyle is wider than
tall, and the foramen magnum is 22% wider than the occipital condyle.  It
differs from Erlikosaurus in having shorter paraoccipital processes and a
more horizontally oriented supraoccipital without a nuchal crest.  Ischium
with distal shaft longer and obturator process larger than Segnosaurus.
Comments- The ischium was originally identified as a Zuniceratops squamosal.
References- Kirkland and Wolfe, 2001. A therizinosaurid (Dinosauria:
Theropoda) braincase from the Middle Turonian (Cretaceous) of North America.
JVP 21(3) 68A.

? undescribed Therizinosauridae
Late Campanian, Late Cretaceous
Dinosaur Park Formation, Alberta, Canada
Material- (CMN 12349) frontal (Sues 1978, Currie 1987, Currie 1992)
(CMN 12355) frontal (Ryan and Russell, 2001)
(RTMP 81.16.231) frontal (Currie 1992)
(RTMP 79.15.1) pedal ungual (Currie 1992)

? undescribed Therizinosauridae
late Maastrichtian , Late Cretaceous
Hell Creek Formation, USA
Material- astragalus
Comments- Thomas Holtz said- Dale Russell listed a therizinosaur astragalus
from the Hell Creek in a big master-list of North American dinosaur
specimens he compiled back in the mid-1980s: that specimen has never seen
the light of (publication) day, so far as I know.
References- Holtz pers. comm. 2001

There are no North American oviraptorids.

Homocephalids do not exist, but are just a paraphyletic grade of basal
pachycephalosaurs.

Nemegtosaurids are titanosaurids, as shown by the discovery of Rapetosaurus.
North American Cretaceous titanosaurids are of course represented by-

Alamosaurus Gilmore 1922
A. sanjuanensis Gilmore 1922
Maastrichtian, Late Cretaceous
Upper Transitional Unit, Arizona, Upper Kirtland F, New Mexico, El Picacho
Formation, Javelina Formation, Texas, North Horn Formation, Utah, US
Reffered- (UALP 4005) proximal caudal vertebra (146 mm) (McCord 1997)
(10-13 m, juvenile) three individuals including cervical, vertebral centrum,
sacral neural spine, sacral ribs, humerus, metacarpal, ilium, pubis, femora,
ungual (Fiorillo and Montgomery, 2001)
Description- The elongate opisthocoelous cervical vertebrae have non-bifid
posteriorly deflected neural
spines with deep postspinal fossae. The dorsal vertebrae have wide spatulate
neural spines with strong prespinal laminae, and lack hyposphene-hypantrum
articulations. Alamosaurus sanjuanensis exhibits a unique morphology of the
ischium, evident even in this juvenile specimen.
Comments- Salgado and Calvo place Alamosaurus as the sister group to
Neuquensaurus and Saltasaurus and more derived than Aeolosaurus.  Lehman and
Coulson place Alamosaurus as sister to the Pieropolis titanosaur and
Neuquensaurus.
References- Mateer. 1976. New Topotype of Alamosaurus sanjuanensis Gilmore
(Reptilia; Saurischia). Bulletin of Geological Institute of University of
Uppsala. v 6, pg 93-95 ((page #'s may be off))
McCord, R.D.  1997.  An Arizona titanosaurid sauropod and revision of the
Late Cretaceous Adobe Canyon fauna.  JVP 17(3):620-622.
Salgado, L., R.A. Coria and J.O. Calvo.  1997.  Evolution of titanosaurid
sauropods. I: phylogenetic analysis based on the postcranial evidence.
Ameghiniana 34(1):3-32.
Sullivan and Lucas, 2000. _Alamosaurus_ (Dinosauria, Sauropoda) from the
Late Campanian and its significance. JVP 20(2)
Fiorillo and Montgomery, 2001. Depositional setting and paleoecological
significance of a new sauropod bonebed in the Javeline Formation
(Cretaceous) of Big Bend National Park, Texas. JVP 21(3) 49A.
Lehman and Coulson, 2001. A juvenile specimen of the sauropod dinosaur
Alamosaurus sanjuanensis from the Upper Cretaceous of Big Bend National
Park, Texas. Journal of Paleontology: Vol. 76, No. 1, pp. 156-172.

undescribed Titanosaurid (Britt, Stadtman, Scheetz and McIntosh 1997,
Kirkland, Lucas and Estep 1998)
Barremian, Early Cretaceous
Yellow Cat Member of Cedar Mountain Formation, Utah, US
Material- (twelve individuals) nearly all skeletal elements including skull,
teeth (60x35 mm), cervical vertebrae, dorsal vertebrae, caudal vertebrae,
sternal plates, humerus, ulna, ilium, femur
Description- teeth spatulate, caudally directed basisphenoid tubera, low
neural spines on all vertebrae, shallowly bifid neural spines on mid and
posterior cervical vertebrae, cervical ribs deeply bifid, high neural arch
peduncles, first caudal centrum biconvex, strongly procoelous caudal centra,
large craniocaudally elongate sternal plates, humerofemoral ratio of .8,
robust deltopectoral crest, well-developed olecranon process, preacetabular
process not ventrally reflected, preacetabular blade laterally reflected 60
degrees from sagittal plane
References- Britt, Stadtman, Sheetz and McIntosh, 1997.
Britt, Sheetz, McIntosh and Stadtman, 1998. Osteological characters in an
Early Cretaceous titanosaurid sauropod dinosaur from the Cedar Mountain
Formation of Utah. JVP 18(3) 29A

undescribed Titanosaurid (Tidwell, Carpenter and Brooks 1999)
Aptian, Early Cretaceous
Ruby Ranch Member of Cedar Mountain Formation, Utah, US
Reference- Tidwell, Carpenter and Brooks, 1999. "New sauropod from the Lower
Cretaceous of Utah, USA," Oryctos 2: 21-37.

unnamed Titanosaurid (Ostrom 1970)
Aptian-Albian, Early Cretaceous
Cloverly Formation, Montana, US
Reference- Ostrom, 1970.

undescribed titanosaur (Wedel, 2000)
Aptian-Albian, Early Cretaceous
Cloverly Formation, Montana, US
Material- partial vertebrae, humeri, ischium, fragmentary pelvic elements,
tibiae, metatarsal, armor?
Comments- Titanosaur affinities are suggested by general morphology.  Many
osteoderms were found, 2-10 cm, pentagonal or hexagonal and pitted on both
faces.  They don't correspond well to titanosaurs or ankylosaurs.
Reference- Wedel, 2000. New material of sauropod dinosaurs from the Cloverly
Formation. JVP 20(3) 77A

Asian Cretaceous "hypsilophodonts"-

Jeholosaurus Xu, Wang and You 2000
J. shangyuanensis Xu, Wang and You 2000
Etymology- "lizard from Jehol, Shangyuan", the first referring to the old
geographical name for western Liaoning and northern Hebei, the second for a
larger geographic locality.
Barremian, Early Cretaceous
Yixian Formation, Liaoning, China
Holotype- (IVPP V 12529) incomplete skull (63 mm), mandibles (59 mm),
cervical vertebrae, caudal vertebrae, femur (90 mm), tibia (107 mm), fibula,
metatarsal I (24 mm), metatarsal II, metatarsal III (55 mm), metatarsal IV,
pedal phalanges
Referred- (IVPP V 12530) incomplete skull (~50 mm), cervical vertebrae
Diagnosis- enlarged laterodorsal nasal foramina; quadratojugal fenestra more
than 25% maximum quadratojugal length; quadratojugal less than 30% of skull
height; predentary almost 150% of premaxillary body length; dentary extends
posteriorly almost to posterior border of angular; metatarsal III placed
more anteriorly than other metatarsals.
Reference- Xu, Wang and You, 2000. A primitive ornithopod from the Early
Cretaceous Yixian Formation of Liaoning. Vertebrata PalAsiatica 38(4)
318-325.

Siluosaurus Dong 1997
S. zhangqiani Dong 1997
Barremian, Early Cretaceous
Lower Xinminbao Group, Gansu, China
Holotype- two teeth
Description- the smallest known hypsilophodontid
References- Dong, Z. 1997. A small ornithopod from Mazongshan Area, Gansu
Province, China. Pp. 24-26. in Dong, Z., ed. Sino-Japanese Silk Road
Dinosaur Expedition. China Ocean Press, Beijing. 114 p.

undescribed Hypsilophodontid
Coniacian-Campanian, Late Cretaceous
Iren Dabasu Formation, China
Material- a few isolated bones (Currie and Eberth 1993)
Reference- Currie and Eberth, 1993. Palaeontology, sedimentology and
palaeoecology of the Iren Dabasu Formation (Upper Cretaceous), Inner
Mongolia, People's Republic of China. Cretaceous Research. 14 127-144

undescribed ?Hypsilophodontid (Russell, Russell and Sweet 1994)
Late Maastrichtian, LC
Pingling Formation, China
Reference- Russell, D.A., D.E. Russell, and A.R. Sweet.  1993.  The end of
the dinosaurian era in the Nanxiong Basin.  VPA 31(2): 139-145.

undescribed Hypsilophodontid (Azuma 1991)
Aptian, EC
Kitadani Formation of the Akaiwa Subgroup of the Tetori Group, Japan
Material- teeth (Azuma 1991)
 skull (100 mm) (anon. 1998)
Habitat- The specimens were transported from a river side to a lake based on
the condition of the bones.  Other inhabitants of the lake included
crocodiles, turtles, mollusks and fish.
Comments- A skull was discovered and reported in a newspaper article in
1998.
Reference- Azuma, 1991. Early Cretaceous Dinosaur Fauna from the Tetori
Group , central Japan. Research on Dinosaurs from the Tetori Group (1).
Professor S. Miura Memorial Volume, 55-

? unnamed Hypsilophodontid (Hasegawa, Ohkura and Manabe 1990)
Berriasian-Hauterivian, EC
Okurodani Formation of the Itoshiro Subgroup of the Tetori Group, Japan
Material- tooth
Habitat- The specimen was deposited in a lake with land plants and mollusks
preserved in the matrix.

No Asian ceratopsids are known, though Turanoceratops may be their sister
group.

The problem with nodosaurs is that they're paraphyletic, with polacanthids
closer to ankylosaurids than things like Sauropelta and Panoplosaurus are.
Where exactly Nodosaurus goes, and therefore what exactly are nodosaurids,
is unknown, but here's the only known Asian Cretaceous non-ankylosaurid-

Liaoningosaurus Xu, Wang and You 2001
L. paradoxus Xu, Wang and You 2001
Etymology- "paradoxical lizard from Liaoning"
Barremian, Early Cretaceous
Yixian Formation, Liaoning, China
Holotype- (IVPP V12560) (330 mm, juvenile) premaxilla, maxilla, mandibles,
quadrate, pterygoid?, basioccipital?, basisphenoid?, paroccipital process?,
teeth, several cervical vertebrae, three dorsal vertebrae, twenty-three
dorsal ribs (to 54 mm), four sacral vertebrae (6 mm), two sacral ribs, about
twenty caudal vertebrae, chevrons, scapulae (32 mm), coracoids, sternal
plate, humeri (27 mm), radii (19 mm), ulnae (21 mm), metacarpus (5 mm),
manual phalanges, manual unguals, ilium (51 mm), proximal pubis, ischia (30
mm), femora (28 mm), tibiae (28 mm), fibulae (25 mm), metatarsus (13 mm),
pedal phalanges, pedal unguals, cervical scutes?, five cervicopectoral
spines (5-8 mm), three cervicopectoral plates (7-11 mm), posteroventral
plate (67 mm)
Diagnosis- sternum trapezoidal with slender, curved and tapered
posterolateral process; enlarged armor plate covering pelvic area ventrally.
Reference- Xu, Wang & You, 2001. A juvenile ankylosaur from China.
Naturwissenshaften: Volume 88 Issue 7 (2001) pp 297-300.

Mickey Mortimer