RE: Dromaeosaurus Tracks?

[Dino Guy Ralph <dinoguy@sbcglobal.net>]

Many thanks to Dan Varner for pointing out the unflexed position of the
"fighting dinosaurs" _Velociraptor_ killer claw toe that lies underneath
_Protoceratops_.  Seeing is believing.

Ray Stanford has found tracks that may be attributable to dromaeosaurids.
We'll have to wait and see what they look like.  I look forward to any hard
evidence that would tell us if the #2 claw was held off the ground in
deinonychosaurs.

I performed a Google search and turned up references to putative didactyl
theropod tracks.  I don't have these papers myself, aside from what is
available on-line at the following web sites.  Any additions to this list or
any articles with good documentation of dromaeosaurid trackways would be
much appreciated!

-----

The following paper, available at
http://cactus.dixie.edu/jharris/Saurexallopus.pdf , refers to "didactyl"
theropod tracks...

*J. D. Harris §, *K. R. Johnson, † J. Hicks and ‡ L. Tauxe
Cretaceous Research (1996) 17, 381 - 401
Four-toed theropod footprints and a paleomagnetic
age from the Whetstone Falls Member of the
Harebell Formation (Upper Cretaceous :
Maastrichtian), northwestern Wyoming

Quote:
"Troodontids and dromaeosaurids share both a greatly reduced digit I and a
specialized digit II. The second pedal digit in these forms is believed to
have been
held retracted and of f the ground in normal locomotion, holding the
‘sickle’ claw
clear from wear. One would expect footprints from either of these groups to
be
didactyl. Such prints are known, although extremely rare
(Deinonychosaurichnus,
Zhen et al., 1987, as cited in Zhen et al., 1989; undescribed DMNH
specimens)."

Zhen, S., Zhen, B., Chen, W. & Zhu, S. 1987. Bird and dinosaur footprints
from the Lower
Cretaceous of Emei County, Sichuan. Abstracts, First International Symposium
on Nonmarine
Cretaceous Correlations, pp. 37 - 38.

--------
The following may or may not be relevant, depending on a proper translation.
It's hard to make out what the abstract actually says in the crude
translation below...
http://www.wanfangdata.com.cn/qikan/periodical.Articles/dzlp/dzlp2004/0406/0
40606.htm

Geological comment
GEOLOGICAL REVIEW Optimum REVIEW
2004 Vol.50 No.6 P.561-5662004 Vol.50 No.6 P.561 - 566

Beipiao, Liaoning region-Late Jurassic Tuchengzi fossils of dinosaur
footprints found


Discovery of Dinosaur Track Fossils from the Middle-Late Jurassic Tuchengzi
Formation in the Chaoyang Area,
Liaoning Province
Discovery of 01/21 Track Fossils from the Middle-Late Jurassic Formation in
the Tuchengzi Chaoyang Area, Liaoning Province

Zhang Yongzhong Wu Ping Zhang Xuebin Zhang Jianping baisong

Abstract: In western North Chaoyang eight votes - South near-Late Jurassic
Tuchengzi found a large number of fossils of dinosaur footprints (theropod.
ornithopod, sauropod). This paper right theropod dinosaur tracks so
reported. Theropod dinosaurs walking for two, 3-toe, narrow movements, the
majority of firms-toe. Fossils are preserved on the level. Split level
development mud and ripples. footprint size from 29.5 cm x 19cm to 4cm × 
3
cm in the footsteps of continuous distribution pose an obvious trace, trace
the direction of the law at the time, the distribution of dinosaur behavior
habits provide reliable evidence. South Bajiazi found in a large number of
small theropod dinosaur footprints show: Beipiao area small theropod
dinosaur in the late Jurassic period Tuchengzi have emerged.

-------

See also
http://www.ingentaconnect.com/content/tandf/gich/2004/00000011/F0020003/art0
0009 :

Dinosaur Tracks from the Cedar Mountain Formation (Lower Cretaceous), Arches
National Park, Utah
Authors: Martin Lockley1; Diane White1; James Kirkland2; Vince Santucci3

Source: Ichnos, Volume 11, Numbers 3-4, Numbers 3-4/2004 , pp. 285-293(9)

Abstract:

The seventh and largest known dinosaur tracksite from the Cedar Mountain
Formation is reported from two important stratigraphic levels in the Ruby
Ranch Member within the boundaries of Arches National Park. Previous reports
of sites with a few isolated tracks are of limited utility in indicating the
fauna represented by track makers. The Arches site reveals evidence of
several theropod morphotypes, including a possible match for the coelurosaur
Nedcolbertia and an apparently didactyl Utahraptor-like dromaeosaurid.
Sauropod tracks indicate a wide-gauge morphotype (cf. Brontopodus).
Ornithischian tracks suggest the presence of an iguandontid-like ornithopod
and a large ankylosaur. Dinosaur track diversity is high in comparison with
other early Cretaceous vertebrate ichnofaunas, and it correlates well with
faunal lists derived from skeletal remains, thus providing a convincing
census of the known fauna.

---------

Plus:
http://cactus.dixie.edu/jharris/GoseongPapers.html

Li, D., Azuma, Y., Fugita, M., Lee, Y.-N., and Arakawa, Y. 2006. A
preliminary report on two new vertebrate track sites including dinosaurs
from the Early Cretaceous Hekou Group, Gansu Province, China; pp. 29-49 in
Lee, Y.-N. (ed.), Proceedings of the 2006 Goseong International Dinosaur
Symposium. Journal of the Paleontological Society of Korea 22.


ABSTRACT: Two track sites were discovered in the Hekou Group (Early
Cretaceous), Yanguoxia, Yongjing County, Gansu Province, China. More than
108 dinosaur and pterosaur trackways occur on the same gray fine sandstone
surface of the two sites. Site 1 (600 m2) contains 245 dinosaur, 25
pterosaur, and 4 bird tracks. A total of 1,392 dinosaur tracks with one
pterosaur track are preserved in the Site 2 (1,000 m2). Dinosaur tracks
attributable to theropods, sauropods, and ornithopods occur in both sites.
One of the theropod trackways in the both site consists of an unusual
didactyl footprints, suggestive of a dromaeosaurid theropod such as
Deinonychus. Unusual sauropod and ornithopod trackways are also found at
both sites, which appear to have been made by swimming sauropods and
ornithopods in shallow water. These include unusual ornithopod trackways
that have tail-drag marks between left and right footprints. A pterosaur
trackway in Site 1 represents the first record of pterosaur footprints in
China, which consists of six pairs of manus and pes and one isolated manus
impression. This pterosaur trackway is also the first record from the Early
Cretaceous in Asia. A comprehensive analysis of the track sites deduced from
overlapping trackway sequences indicates that the sedimentary environment
changed gradually from terrestrial into lacustrine condition. The
co-occurrence of dinosaur tracks such as theropods, sauropods, and
ornithopods with pterosaur and bird tracks shows a unique faunal association
in this area in the Early Cretaceous of China.

-------

http://www.informaworld.com/smpp/content~content=a714008144~db=all

Grallator-Dominated Fossil Footprint Assemblages and Associated Enigmatic
Footprints from the Chinle Group (Upper Triassic), Gateway Area, Colorado
Authors: Robert Gaston a; Martin G. Lockley b; Spencer G. Lucas c; Adrian P.
Hunt c
Affiliations:    a Gaston Design Studio, Fruita, Colorado, USA.
 b Geology Department, University of Colorado at Denver, Denver, Colorado,
USA.
 c New Mexico Museum of Natural History and Science, Albuquerque, New
Mexico, USA
Published in:  Ichnos, Volume 10, Issue 2 - 4 April 2003, pages 153 - 163

Abstract
The upper part of the Chinle Group (Late Triassic) of the Gateway area in
western Colorado is extraordinarily rich in fossil footprint assemblages.
Dominant track types include small Grallator tracks, generally attributed to
Coelophysis-like theropods, which often occur in high densities of 50 to 100
per m2. Other abundant ichnotaxa that are attributable to dinosaurs or
dinosaur-like archosaurs include Pseudotetrasauropus and Tetrasauropus,
attributed to prosauropods and sauropods, respectively. Several
Pseudotetrasauropus-like tracks appear to be functionally didactyl and may
indicate a new ichnotaxon that represents an animal that shows certain
unusual features that are convergent with dromaeosaurs and certain birds.
Such convergence may reflect inherent growth programs as much as functional
adaptations. Non-dinosaurian ichnotaxa include Brachychirotherium (probably
of aetosaur affinity) and Rhynchosauroides, attributed to a
sphenodontid/lizard-like form. Other ichnotaxa include probable therapsid
(dicynodont) tracks labeled Pentasauropus sp., mammaloid (non-therian mammal
and/or mammal-like reptile) tracks, and the trails of arthropods.

Excellent preservation and high track densities mark the Gateway assemblages
in a thin stratigraphic interval in the upper part of the Chinle Group (Rock
Point Formation). The track assemblages are similar to those reported from
the Chinle Group in other parts of the Colorado Plateau and Rocky Mountain
region, extending over most of Colorado, Utah, northern Arizona and northern
and eastern New Mexico. Some of the Chinle ichnotaxa (Grallator and
Brachychirotherium) are found in the overlying Wingate Formation, indicating
that it is also Late Triassic in age, at least in the lower part. However,
overall the Chinle and Wingate assemblages are quite different, most notably
in the rarity of mammaloid/mammal-like tracks in the Chinle Group.
Keywords: Upper Triassic; Chinle Group; Grallator; Brachychirotherium;
Rhynchosauroides; didactyl tracks

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http://www.cgs.gov.cn/magazine/dzyuqk/tb/2005/200503/012.htm


Li R H， Liu Ｍ W， Lockley Ｍ R． Early 
Cretaceous dinosaur tracks from the
Houzuoshan Dinosaur Park in Junan County， Shandong Province， 
China．
Geological Bulletin of China， 2005， 
24（3）：277−280

Abstract： Abundant and diverse dinosaur tracks， associated with 
small
numbers of fossil bird tracks， were discovered in the Tianjialou 
Formation
of the Early Cretaceous Dasheng Group in the Houzuoshan Dinosaur Park，
Junan County， Shandong Province． Preliminary study shows that the
ichnofauna is mainly theropod and ornithopod tracks， with the former
predominating． The largest one is elliptical in shape， 100 cm 
long and 70
cm wide， which is probably a ornithopod track． The ornithopod 
tracks are
mostly elliptical in shape， the long axis being generally 30 to 40 cm
long， and are usually preserved as undertracks． The largest 
theropod track
in this tracksite is a tridactyl track， 49 cm long by 35 cm wide，
attributable to carnosaurs． Furthermore， several possible 
dromaeosaurid
tracks were also recognized， which are bidactyl， with digits 
Ⅲ and Ⅳ
nearly parallel to each other and the so−called digit Ⅱ forming 
nodes at
the inner proximal part of digit Ⅲ． The horizon of ornithopod tracks is 
of
restricted distribution but the tracks are close−spaced． 
Ｍud cracks，
ripples and even ice−crystal imprints are common on the bedding 
planes，
which is closely related to mudstone and silty mudstone．

Hope this helps!

Dino Guy Ralph
Docent at the California Academy of Sciences
Dinosaur and Fossil Education
Member of the Society of Vertebrate Paleontology