Content uploaded by Vladimir Alifanov
Author content
All content in this area was uploaded by Vladimir Alifanov on May 31, 2016
Content may be subject to copyright.
73
Paleontological Journal, Vol. 38, No. 1, 2004, pp. 73–77. Translated from Paleontologicheskii Zhurnal, No. 1, 2004, pp. 68–72.
Original Russian Text Copyright © 2004 by Tumanova, Bolotsky, Alifanov.
English Translation Copyright © 2004 by
åÄIä “Nauka
/Interperiodica” (Russia).
INTRODUCTION
A large accumulation of fossil bones was discovered
in 1990 in a road cut between the Mutnaya and Udur-
chukan rivers (southeastern Amur Region, Fig. 1). Ver-
tebrate remains were found in grayish green clays with
gravel inclusions, which compose a part of the Udur-
chukan Formation (Bugdaeva
et al.
, 2001). The bone
beds are mixtites by genesis, that is, they were formed
as a result of mudstream flows from the heights
(Markevich
et al.
, 1994; Bugdaeva
et al.
, 2000). The
fossiliferous layers of the new locality named Kundur
is dated by palynological data as the Early Maastrich-
tian (Markevich and Bugdaeva, 1999; Bugdaeva
et al.
,
2001).
To date, the collection from Kundur totals more than
a thousand isolated bones, complete skeletons, and
their parts. The bulk of the material consists of duck-
billed dinosaurs of the families Hadrosauridae and
Lambeosauridae. The deposits yielded isolated teeth of
carnivorous dinosaurs of the families Tyrannosauridae
and Dromaeosauridae and fragmentary remains of tur-
tles (Lindholmemydidae, Trionychidae) and crocodile
teeth (
Shamosuchus
sp.) (Bolotsky and Moiseenko,
1988; Moiseenko
et al.
, 1997; Bolotsky and Alifanov,
2001; Danilov
et al.
, 2002).
In 1991, in the Kundur locality, the paleontological
team from the Amur Complex Research Institute of the
Amur Scientific Center, Far East Division, Russian
Academy of Sciences (AEIM) found armored dino-
saurs, which had previously been unknown in the Amur
Region. The present paper describes these remains and
discusses their taxonomic position.
MATERIAL
Materials described in this report include three
bones: specimen AEIM, no. 2/1, a tooth with a slightly
damaged anterior edge, a worn labial crown surface,
and a broken off root (Figs. 2a, 2b); specimen AEIM,
no. 2/2, an incomplete tooth, including the basal part of
the crown and the root base (Figs. 2c, 2d); and speci-
men AEIM, no. 2/16, an osteodermal scute (Fig. 3). All
bones come from the deposits of the Udurchukan (the
lowermost part of the Tsagayan) Formation of the Kundur
locality (Arkharinskii District, Amur Region, Russia).
The First Finds of Armored Dinosaurs in the Upper Cretaceous
of Russia (Amur Region)
T. A. Tumanova*, Yu. L. Bolotsky**, and V. R. Alifanov*
*Paleontological Institute, Russian Academy of Sciences, Profsoyuznaya ul. 123, Moscow, 117997 Russia
e-mail: mfedon@paleo.ru
**Amur Institute of Integrated Research, Far East Division, Russian Academy of Sciences,
Relochnyi per. 1, Blagoveshchensk, 675000 Russia
Received August 6, 2002
Abstract
—Remains of armored dinosaurs (Thyreophora) from the Late Cretaceous, Early Maastrichtian
(Udurchukan Formation) deposits of the Kundur locality in the Amur Region, are described. The material
includes a single osteodermal scute of extraordinary structure and two cheek teeth. These fossils are tentatively
assigned to the family Nodosauridae (Ankylosauria) previously unknown in Asia.
Key words
: Armored dinosaurs, Upper Cretaceous, Russia, Amur Region.
BLAGOVESHCHENSK
RAICHIKHINSK
OBLUCH’E
Zeya R.
Tom’ R.
Gil’cin R.
Bureya R.
Amur R.
Arkhara R.
ZAVITINSK
Mutnaya R.
BELOGORSK
Fig. 1.
A map of part of the Amur Region. Designation:
Kundur locality.
74
PALEONTOLOGICAL JOURNAL
Vol. 38
No. 1
2004
TUMANOVA
et al
.
DESCRIPTION
Available teeth are similar in size and structure. The
crown is leaf-shaped and compressed labiolingually. Its
edges bear denticles separated from each other by shal-
low grooves terminating before reaching the cingulum.
Six denticles are located anterior to the apical cusp, and
three or four are located posteriorly to it. The apical
cusp is wide, its cutting edge is worn and slightly dis-
placed backwards with reference to the tooth midline.
The smallest marginal denticles are close to the base.
They are less worn than the others and their apices are
pointed. In relation to the axis of the apical cusp, the
axis of the anterobasal supplementary denticles is
inclined at an angle of about
60°
. The cingulum is wide;
its apical edge is outlined by a deep groove and the
basal edge gradually passes into the base. In the frontal
view, the cingulum is asymmetrical; on one side of the
crown it is higher than on the other and its maximum
expansion is in the central part. Labially, the cingulum
is crescent shaped, with its arch facing basally. Lin-
gually, it is sinusoid; the highest point of the wave is at
the middle of the tooth. The tooth crown of each speci-
men is 10 mm long, the labiolingual thickness at the
cingulum is 6 mm. The crown height from the cingulum
base is 10 mm. The diameter of the preserved part of the
root is 6 mm.
The osteoderm is conical, compressed from both
sides without keel formation. From the base plane to
the top, it is 125 mm high. The osteoderm apex is wide
and rounded and shows a cellular surface structure. In
the lateral view one edge of this bone looks convex,
while the other is straight, its lower part being slightly
bent externally. In the anterior or posterior view, one
side of the osteoderm is slightly arched externally and
the other is curved internally. The bone is thick-walled.
The maximum thickness of the wall is 25 mm. There
are no foramina in the walls. The vessel grooves run-
ning on the osteoderm surface are meandering, branch-
ing, more often interrupted than extending from the
base to the apex. The projection of the osteoderm base
is pear-shaped. Its narrower edge corresponds to the
convex edge of the lateral projection. The osteoderm
base is 165 mm, and its maximum width is 100 mm.
The bone edges are uneven, without thickening. The
osteoderm base is dome-shaped. The dome apex is dis-
placed to the middle of the narrow part of the base pro-
jection. The osteoderm body is penetrated by a narrow
vertical canal passing towards the apex.
DISCUSSION
Some difficulties arise in the identification of iso-
lated dinosaur osteoderms. This is due to the fact that in
(a) (b)
(c) (d)
Fig. 2.
Ankylosaurian teeth from the Kundur locality,
×
4: (a, b) specimen AEIM, no. 2/1: (a) labial and (b) lingual views; (c, d) specimen
AEIM, no. 2/2: (c) labial and (d) lingual views; Amur Region, Arkhara District, Kundur locality; Udurchukan Formation, Lower
Maastrichtian.
PALEONTOLOGICAL JOURNAL
Vol. 38
No. 1
2004
THE FIRST FINDS OF ARMORED DINOSAURS IN THE UPPER CRETACEOUS OF RUSSIA 75
addition to the Thyreophora (armored dinosaurs in a
broad sense), certain other ornithischian groups, such
as some sauropods, have osteodermal elements on their
trunk (Ford, 2000). Therefore, the assignment of the
Kundur osteoderm to the Thyreophora is not certain,
although probable. At the same time, the belonging of
the teeth described above to thyreophorans is beyond
question.
The wandering and interrupted vessel grooves on
the osteoderm surface differ from the vessel traces on
the surface of stegosaurian spines, whose grooves
stretch over the entire extent of the spine, which sug-
gests constant and parallel growth of osteoderms and
overlaying horn cover. The oval and concave spine base
containing a narrow vertical internal canal disagrees
with the nature of stegosaur osteoderms.
The teeth of ankylosaurs and stegosaurs are similar
in morphology; however, in ankylosaurs, marginal
crown denticles are more pointed (Barrett, 2001), while
in stegosaurs the vertical ribbing of lateral crown sur-
faces is sharper (original data). Both characteristics dis-
agree with the assignment of teeth from Kundur to
stegosaurs.
However, the osteoderm and teeth are only tenta-
tively identified because the material includes isolated
fragmentary specimens. Therefore, when finding out
the taxonomic relationship of teeth and osteoderms, the
data on the geological and geographical distribution of
the Thyreophora should be taken into account.
Stegosaurs are the most widespread thyreophorans
of the Jurassic and Early Cretaceous periods. This
group has been found in North America, Africa,
Europe, and Asia. The report on Late Cretaceous stego-
saurs from India (Yadagiri and Ayyasami, 1979) is
based on a fragmentary specimen and can not be con-
sidered absolutely veritable (Dong, 1990).
The order Ankylosauria, including the families
Nodosauridae and Ankylosauridae, has been discov-
ered on every continent, including Antarctica (Olivero
et al.
, 1987). In Europe, only nodosaurids are known.
(a) (b)
(c)
(d)
Fig. 3.
Dermal scute of Ankylosauria from Kundur, specimen AEIM, no. 2/16,
×
0.5: (a, b) lateral, (c) caudal, and (d) ventral views;
Amur Region, Arkhara District, Kundur locality; Udurchukan Formation, Lower Maastrichtian.
76
PALEONTOLOGICAL JOURNAL
Vol. 38
No. 1
2004
TUMANOVA
et al
.
All Gondwanian forms also belong to this family. In
Asia, only ankylosaurids have been found. Members of
both families co-occurred only in North America (Car-
penter, 1997).
Nodosaurids persisted from the Middle Jurassic to
the terminal Maastrichtian. In the North American
west, the last member of this family,
Edmontonia
, was
found in the Upper Maastrichtian Lance, Hell Creek,
and Laramie formations; however, it only occurred in
the lower parts of these formations. Remarkably, the
finds mainly consist of skeletal fragments and isolated
teeth, and, upsection, they become more scarce. The
analysis of localities containing
Edmontonia
made pos-
sible a slight extension of the time range of nodosaurids
(Carpenter and Breithaupt, 1986), in contrast to the pre-
vious opinion, according to which this group survived
only until the Campanian.
The time range of ankylosaurids comprises almost
the whole Late Cretaceous and includes the terminal
Early Cretaceous. The latest Asian ankylosaur,
Tarchia
gigantea
(Maleev, 1956), occurs in the deposits of the
Nemegt Formation in southern Mongolia and is dated
within a wide range, from the Middle Santonian (Ali-
fanov, 2000) to the terminal Maastrichtian (Shuvalov,
1982; Barsbold, 1983). Taking into account the similar-
ity of the Late Cretaceous faunas from North America
and Paleoasia, the absence of nodosaurids in the latter
continent seems rather puzzling.
The assignment of the thyreophoran remains from
Kundur to stegosaurs is less probable not only by virtue
of some morphological features, but also by their Late
Cretaceous age. Thus, they may be referred to ankylo-
saurs.
Coombs and Marya ska (1990) traced the following
familial distinctions in ankylosaur dental structure. In
nodosaurids, the tooth crown is more strongly com-
pressed laterally, the grooves on the flanks are better
developed, and the cingulum is always clearly formed
and asymmetrical (it is thicker on the labial side of the
crown and is sinusoidal on the lingual side). Ankylo-
saurids more often have a distinct expansion at the
crown base rather than a true cingulum. Interestingly,
an ankylosaur from Antarctica originally identified as
an ankylosaurid (Olivero
et al.
, 1987) was subsequently
transferred to nodosaurids on the basis of its dental
morphology (Gasparini
et al.
, 1996). The dental mor-
phology of the ankylosaur from Kundur suggests that it
could be a nodosaurid. Thus, the large size of the teeth
described above and the degree of cingulum expression
correspond to the nodosaurid characteristics listed
above.
Attempts to make generic diagnoses with the use of
dental characteristics were undertaken earlier (Leidy,
1856; Brown, 1908); however, it is not yet possible to
perform such identifications with confidence. There
might be a sole characteristic in the generic diagnosis
worth credibility: the w-shaped cingulum in the teeth of
the ankylosaurid
Maleevus disparoserratus
from Mon-
n
′
golia. However, in this form, teeth vary in structural
details even within the same tooth row.
The ankylosaurian dermal armor consists of numer-
ous diverse elements, which, while fusing together,
may form certain constructions, such as half-rings,
shields, and others. The taxonomic significance of
osteodermal elements in ankylosaurs has been not quite
clear until now. This is because of an insufficient
amount of well-preserved articulated armor elements
in
situ.
Nevertheless, Coombs and Marya ska (1990)
indicated some diagnostic characteristics that distin-
guish members of the two families. For example, the
ventral surface of ankylosaurids’ keeled scutes is rather
strongly concave, that is, the spines are thin-walled and
hollow, while the nodosaurid scute base is flat or only
slightly concave even if the keel is high. The surface of
nodosaurid scutes and spines is dense, whereas ankylo-
saurids, show a trend towards augmentation of the
amount of pores, in the osteodermal walls of the late
forms. For example, the osteoderm walls of the latest
Mongolian ankylosaur
Tarchia gigantea
look open-
work (Tumanova, 1987). Ankylosaurids don’t possess
high conical spines, whereas the height of some nodo-
saurid osteoderms exceeds the diameter of their base by
two times. The thick walls of the spine from Kundur,
the structure of its base, and its dense surface texture
suggest that this osteoderm belongs to a member of the
family Nodosauridae.
At the same time, the absence of keel in the Kundur
osteoderm combined with its considerable height is an
unusual characteristic for dermal ossifications in the
known members of both ankylosaurian families. One
more distinctive feature of the described spine is the
cellular surface structure of its apex, which has not been
registed in other ankylosaurian osteoderms. The posi-
tion of the osteoderm on the animal’s body is difficult
to determine, although its asymmetric structure
excludes its axial localization.
Thus, taking into account the structure of the osteo-
derm and jaw teeth and their large size, the hypothesis
of the relation of the Kundur thyreophoran to nodosau-
rids looks preferable. This makes the remains from
Kundur the first find of a member of the Nodosauridae
in Asia.
If it is hypothesized that the thyreophoran from
Kundur belongs to ankylosaurids, geographical the
range of Asian ankylosaurs would be enlarged east-
wards and northwards, and this form from the Amur
Region becomes a candidate to be the largest member
of the family, since its teeth exceed in size the teeth of
the largest known Asian ankylosaurid
Tarchia
(which
was more than 7 m long) by approximately one-third.
ACKNOWLEDGMENTS
This work was supported by the Russian Foundation
for Basic Research, project nos. 00-15-97754 and
00-04-49348.
n
′
PALEONTOLOGICAL JOURNAL
Vol. 38
No. 1
2004
THE FIRST FINDS OF ARMORED DINOSAURS IN THE UPPER CRETACEOUS OF RUSSIA 77
REFERENCES
1. V. R. Alifanov,
Macrocephalosaurs and Early Stages of
the Evolution of Lizards from Central Asia
(Paleontol.
Inst. Ross. Akad. Nauk, Moscow, 2000) [in Russian].
2. P. M. Barrett, in
The Armored Dinosaurs
, Ed. by K. Car-
penter (Indiana Univ. Press, Bloomington, 2001),
pp. 25–52.
3. R. Barsbold,
Predatory Dinosaurs from Mongolia
(Nauka, Moscow, 1983) [in Russian].
4. Yu. L. Bolotsky and V. R. Alifanov, Priroda, No. 6, 67
(2001).
5. Yu. L. Bolotsky and V. G. Moiseenko,
On Dinosaurs
from the Amur Region
(AmurKNII DVNTs Akad. Nauk
SSSR, Blagoveshchensk, 1988) [in Russian].
6. B. Brown, Bull. Am. Mus. Natur. Hist.
24
(12), 187
(1908).
7. E. V. Bugdaeva, V. S. Markevich, Yu. L. Bolotsky, and
A. P. Sorokin, Vestn. Dal’nevost. Otd. Ross. Akad. Nauk,
No. 1, 80 (2000).
8. E. V. Bugdaeva, V. S. Markevich, A. P. Sorokin, and
Yu. L. Bolotsky, in
Flora and Dinosaurs at the Boundary
of the Cretaceous and Paleogene in the Zeya–Bureya
Basin
(Dal’nauka, Vladivostok, 2001), pp. 25–43 [in Rus-
sian].
9. K. Carpenter, in
Encyclopedia of Dinosaurs
, Ed. by
P. J. Currie and K. Padian (Academic, San Diego, 1997),
pp. 16–20.
10. K. Carpenter and B. Breithaupt, J. Vertebr. Paleontol.
6
(3), 251 (1986).
11. W. P. Coombs, Jr., Paleontology
21
, 143 (1978).
12. W. P. Coombs, Jr., in
Dinosaur Systematics: Approaches
and Perspectives
(Cambridge Univ. Press, Cambridge,
1990), pp. 269–279.
13. W. P. Coombs, Jr. and T. Marya ska, in
The Dinosauria
,
Ed. by D.B. Weishampel
et al.
(Univ. California Press,
Berkeley, 1990), pp. 456–483.
14. I. G. Danilov, Yu. L. Bolotsky, A. O. Averianov, and
I. V. Donchenko, Russ. J. Herpetol.
9
(2), 155 (2002).
15. Z. M. Dong, in
Dinosaur Systematics: Approaches and
Perspectives
(Cambridge Univ. Press, Cambridge,
1990), pp. 255–268.
16. T. Ford, in
Dinosaurs of New Mexico
, Ed. by S. G. Lucas
and A. B. Heckert (New Mexico Mus. Natur. Hist.,
2000), pp. 157–176.
17. Z. Gasparini, X. Pereda-Suberbiola, and R. E. Molnar,
Mem. Queensl. Mus.
39
(3), 583 (1996).
18. J. Leidy, Proc. Acad. Nat. Sci. Philad.
8
, 72 (1856).
19. V. S. Markevich and E. V. Bugdaeva, Geol. Pacif. Ocean
14
, 977 (1999).
20. V. S. Markevich, Yu. L. Bolotsky, and E. V. Bugdaeva,
Tikhook. Geol., No. 6, 96 (1994).
21. V. G. Moiseenko, A. P. Sorokin, and Yu. L. Bolotsky,
Vestn. Dal’nevost. Otd. Ross. Akad. Nauk, No. 3, 31
(1997).
22. E. B. Olivero, Z. Gasparini, C. A. Rinaldi, and R. Scasso, in
Geological Evolution of Antarctica
, Ed. by M. R. A. Thom-
son
et al.
(Cambridge Univ. Press, Cambridge, 1987),
pp. 617–622.
23. V. F. Shuvalov, in
Mesozoic Lacustrine Basins of Mon-
golia
(Nauka, Leningrad, 1982), pp. 18–68 [in Russian].
24. R. M. Sullivan, Contrib. Sci. Natur. Hist. Mus. Los
Angeles County
391
, 1 (1987).
25. T. A. Tumanova,
Armored Dinosaurs of Mongolia
(Nauka, Moscow, 1987) [in Russian].
26. P. Yadagiri and K. Ayyasami, J. Geol. Soc. India
20
, 521
(1979).
n
′
