hungarosaurus tormai, a new ankylosaur

Transkrypt

Journal of Vertebrate Paleontology 25(2):370–383, June 2005
© 2005 by the Society of Vertebrate Paleontology
HUNGAROSAURUS TORMAI, A NEW ANKYLOSAUR (DINOSAURIA) FROM THE UPPER
CRETACEOUS OF HUNGARY
1
ATTILA ŐSI1
Department of Paleontology, Eötvös Loránd University, Budapest, 1117, Hungary
ABSTRACT—A new ankylosaur Hungarosaurus tormai gen. et sp. nov. from the Upper Cretaceous (Santonian) Csehbánya Formation of the Bakony Mountains, western Hungary is described here. Among the four discovered specimens
of this new armored dinosaur the best preserved is the most complete ankylosaur presently known from the Upper
Cretaceous of Europe. Although many cranial characters of Hungarosaurus are not determinable, a preliminary phylogenetic analysis places Hungarosaurus in the Nodosauridae as a basal nodosaurid. Hungarosaurus is clearly distinguishable from Struthiosaurus on the basis of the dorsoventrally wide quadratojugal, the presence of bony protuberances on
the quadratojugal and postorbital, the robust mandibular quadrate condyle, and the interpterygoid vacuity. The analysis
suggests that Hungarosaurus appears to be more derived than Struthiosaurus, but more primitive than the North American Silvisaurus, Sauropelta, and Pawpawsaurus.
INTRODUCTION
Ankylosaur material from the Upper Cretaceous of Europe is
often rare and mostly fragmentary, especially when compared to
that from North America and Asia. Nevertheless, ankylosaur
remains are known from England, eastern Austria, western Romania, southern France, and northern Spain (Huxley, 1867; Bunzel, 1871; Nopcsa, 1915, 1929; Pereda-Suberbiola, 1992; Garcia
and Pereda-Suberbiola, 2003). Acanthopholis horridus Huxley,
1867, from the Cenomanian of England may be a nomen dubium
(Coombs and Maryanska, 1990). Struthiosaurus is the only
known valid genus in the Late Cretaceous of Europe, and has
three species: S. austriacus Bunzel, 1871, S. transilvanicus Nopcsa, 1915, and S. languedocensis Garcia and Pereda-Suberbiola,
2003. Coombs and Maryanska (1990:476), however, questioned
the validity of Struthiosaurus. Rhodanosaurus Nopcsa, 1929,
from the Campanian-Maastrichtian of southern France, is regarded as nomen dubium and the material is assigned to Nodosauridae indeterminate (Coombs and Maryanska, 1990; PeredaSuberbiola 1993).
In 2000, a new vertebrate fossil locality was discovered in the
Upper Cretaceous of Hungary (Fig. 1). Along with fishes, amphibians, turtles, crocodiles, lizards, and pterosaurs, the first
Hungarian dinosaur remains were found including teeth of a
small dromaeosaurid-like theropod, a Rhabdodon-like ornithopod, and an indeterminate ankylosaur (Ősi in press). In 2001,
three partial ankylosaur skeletons (MTM Gyn/404, holotype),
MTM Gyn/405., MTM Gyn/406.) were collected; unfortunately
the exact locality of MTM Gyn/405. is unknown (Ősi et al., 2003).
In 2003, a fourth specimen, MTM Gyn/407. was collected. This
very rich and well-preserved material represents the most complete ankylosaur from the Upper Cretaceous of Europe and
shows differences from the nodosaurid taxon Struthiosaurus. All
of the material is housed in the Hungarian Natural History Museum in Budapest.
GEOLOGICAL SETTING
The vertebrate locality is an open-pit bauxite mine situated
near the village of Iharkút, in the Bakony Mountains. The fossil
bones occur in the Upper Cretaceous Csehbánya Formation,
which is deposited on the Upper Cretaceous Halimba Bauxite
Formation. The Halimba Bauxite Formation in turn was deposited on the karst topography of the Upper Triassic Main Dolomite. Fossil materials are exposed when overburden of the Cseh-
FIGURE 1.
Location map of the Iharkút locality in Hungary.
bánya Formation is removed. The Csehbánya Formation is a
floodplain and channel deposit formed by variegated clay, silt
with interbedded grey and brown sand, and sandstone beds (Jocha-Edelényi, 1997). One of the bone-yielding beds consists of
sand, silt, and clay pebbles with fragmentary bones accumulated
in fossil pockets. Another bone-yielding bed is a brownish sandstone bed, which included three partial skeletons of the new
ankylosaur. The fourth specimen was collected from loose
blocks. Based on palynology, the age of the Csehbánya Formation is Santonian (Knauer and Siegl-Farkas, 1992).
Institutional Abbreviations—AMNH, American Museum of
Natural History, New York, USA; BMNH, Natural History Museum (British Museum [Natural History]), London, United
Kingdom; MCNA, Museo de Ciencias Naturales de Alava, Vitoria, Spain; MDE, Musée des Dinosaures, Espéraza, France;
MTM, Magyar Természettudományi Múzeum (Hungarian Natural History Museum), Budapest, Hungary; PIUW, Paläontologisches Institut der Universität Vienna, Wien, Austria; USNM,
United States National Museum, Washington, USA; YPM, Peabody Museum,Yale University, New Haven, USA.
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ŐSI—NEW ANKYLOSAUR FROM HUNGARY
TAPHONOMY
The holotype locality is approximately 55 meters square as
calculated from its bone map. All of the 450 bones of MTM
Gyn/404. were disarticulated on the surface of a grey sandstone
bed which was covered with fine sand and silt. Ninety-nine percent of the bones recovered from the locality are from an armored dinosaur, with turtle plastron fragments and crocodile
teeth forming the remainder. The overlying bed contains many
carbonized plant fragments and an enantiornithine bird femur.
Nevertheless, no armored dinosaur bones recovered at this fossil
site indicate more than one specimen of Hungarosaurus. The
only recognizable articulated part of the skeleton is the right
distal forelimb with the radius and four metacarpals. The other
parts of the skeleton are disarticulated, but associated. For example, the caudal, dorsal, and cervicocranial regions of the carcass can be easily identified in relation to each other. Disarticulation is primarily due to modest fluvial transport. However, the
crushed dorsal rib fragments indicate that trampling may also
have been an agent in skeletal disarticulation (Ősi et al., 2003).
One of the distinct aspects of the new Hungarian vertebrate
locality is the very high abundance of armored dinosaur bones.
More than 80% of the dinosaur assemblage is represented by
ankylosaurs, presented by four partial skeletons and also by hundreds of scattered bones.
SYSTEMATIC PALEONTOLOGY
ORNITHISCHIA Seeley, 1888
THYREOPHORA Nopcsa, 1915
ANKYLOSAURIA Osborn, 1923
NODOSAURIDAE Marsh, 1890
HUNGAROSAURUS, gen. nov.
Type Species—Hungarosaurus tormai described below.
Etymology—Named after Hungary.
Diagnosis—As for the species.
HUNGAROSAURUS TORMAI, sp. nov.
Holotype—MTM Gyn/404., skull fragments (premaxilla with
one tooth, left lacrimal, left prefrontal, right postorbital, jugal,
and quadratojugal, left frontal, vomer, pterygoid, right quadrate,
part of the left quadrate, basioccipital, 21 isolated teeth, one
hyoid bone), parts of the right mandible (anterior part of the
dentary, surangular, angular, small posterior part of the dentary),
three cervical vertebrae, six dorsal vertebrae, ten caudal vertebrae, three cervical and 13 dorsal ribs, five chevrons, some tendon fragments, complete left scapulocoracoid, right scapula and
anterior part of the right coracoid, right radius with four metacarpals, preacetabular parts of the left and right ilia, left ischium,
right femur, right fibula, and more than a hundred osteoderms.
Etymology—After my friend András Torma with whom the
locality was discovered.
Type Locality—Iharkút, Veszprém County, Bakony Mountains, Transdanubian Range, western Hungary.
Type Horizon—Csehbánya Formation, Upper Cretaceous
(Santonian).
Paratypes—MTM Gyn/405., one anterior dorsal vertebra, cervical and dorsal ribs, one half-ring osteoderm, some small circular osteoderms; MTM Gyn/406., fragmentary ulna, ddistal end of
a femur?, one metapodium, fragmentary ribs and osteoderms;
MTM Gyn/407., sacrum with sacral rod, left ilium, right fragmentary ilium, left and right ischia, sacral, fused osteoderm.
Diagnosis—Armored dinosaur, approximately 4 m long; large
notch at front of premaxillae, thin nasal process of premaxillae,
robust rhomboidal quadrate condyles, large interpterygoid vacuity, dorsoventrally wide quadratojugal with strong protuberance,
posterodorsally oriented crest-like protuberance on postorbital,
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short diastema between symphysis and first dentary tooth position, very short retroarticular process of surangular, anteriormost dorsal vertebra with unusual transversely wide, anteroposteriorly short amphycoelous centrum, with very large neural canal, dorsally displaced pseudoacromial process of scapula.
DESCRIPTION AND COMPARISONS
Skull and Mandible
The skull (holtype: MTM Gyn/404) is fragmentary and disarticulated. Most of the dorsal part, the occipital and maxillary
regions of the skull are missing. Thus, the exact measurements of
the skull are unknown. A hypothetical reconstruction of the skull
was made based on comparison of the skull elements with those
of Pawpawsaurus (cast) and Struthiosaurus transylvanicus
(BMNH 4966). Based on the length of the frontal, the high premaxilla, and the posterior rim of the large orbit, the skull was
longer than wide, and higher and larger than that of Pawpawsaurus. The estimated length of the skull is approximately 32–
36 cm.
Rostral Region
Premaxilla—The left and right premaxillae (Fig. 2) and a
small posterior part of the left premaxilla with a small anterior
fragment of the maxilla were found separate from each other.
There are three (or possibly four) alveoli. A strong suture is
visible between the premaxilla and the maxilla. This is the only
visible suture in the skull elements of Hungarosaurus. On the left
premaxilla the nasal process projects posterodorsally and on its
dorso-lateral surface bears two ridges. The nasal process of the
right premaxilla is crushed. The right premaxilla bears a single,
very small tooth. Premaxillary teeth are characteristic of basal
nodosaurids such as Pawpawsaurus, Silvisaurus, and Struthiosaurus (see Nopcsa, 1929; Eaton, 1960; Lee, 1996, respectively) and
primitive ankylosaurids such as Gargoyleosaurus (Carpenter et
al., 1998). The complete premaxilla is high but not as transversely
wide as in Pawpawsaurus (Lee, 1996:fig. 4). In dorsal view it is
rounded and rostrolaterally it has ornamentation extending to
the rostrolateral edge of the cutting margin. Anteriorly the
paired premaxillae present a very large, inverted U-shaped
opening or notch. The palatal part of the premaxilla is strongly
concave and surrounded by a narrow, ridge-like cutting margin.
Prefrontal—The left prefrontal (Fig. 2G, H) is polygonal, and
the slightly concave dorsolateral surface is grooved. The posterior margin forming the anterior orbital wall is smooth with tiny
grooves. A suture runs on the internal surface of the prefrontal
anterodorsally and connected posteroventrally to the anterior
orbital wall. Similar suture-like walls are present in Animantarx,
but the function of this suture is unknown (Carpenter, pers.
comm.).
Lacrimal—The left lacrimal (Fig. 2G, H) is preserved connected nearly to the prefrontal. It is quadrangular and the lateral
surface is grooved. The wall of the lacrimal is thin dorsally but
widens ventrally. The articular suface for the maxillary suture is
straight and grooved. The ventral part of the lacrimal bears a
channel, probably the nasolacrimal canal running anteroposteriorly. The posterior region probably forming the anteroventral
part of the orbital wall is crushed.
Temporal Region
Postorbital and Jugal—The postorbital and jugal (Fig. 3)
form the postorbital bar; it is roughly circular and on the ventral
and posterior parts bears an edge. The internal surface of the
postorbital is slightly concave dorsoventrally. The dorsomedial
part of the postocular shelf is crushed, but it appears to be very
narrow. No suture is visible between the postorbital and jugal.
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JOURNAL OF VERTEBRATE PALEONTOLOGY, VOL. 25, NO. 2, 2005
FIGURE 2. Hungarosaurus tormai, gen. et sp. nov., (MTM Gyn/404, holotype). A, premaxillae in ventral view; B, dorsal view; C, rostral view; D,
lateral view; E, left frontal in dorsal view; F, ventral view; G, left prefrontal and lacrimal in lateral view; H, medial view. Abbreviations for figures:
a, alveolus; aeo, anterior edge of the orbit; an, angular; ap, acromion process; asm, articular surface for the maxilla; asq, articular surface for the
quadrate; cf, coracoid foramen; ch, chevron; cm, cutting margin; d, diastema; di, diapophysis; en, external naris; eptf, edge of the posttemporal
fenestra; ft, fourth trochanter; gc, glenoidal cavity; ipv, interpterygoid vacuity; ismb, insertion surface for the M. biceps supracoracoideus and for M.
brachialis; ismi, insertion surface for M. iliofibularis; j, jugal; l, lacrimal; mc, Meckelian canal; n, notch; np, nasal process; ns, neural spine; o,
ornamentation; p, parapophysis; pf, prefrontal; pos, postocular self; pp, postorbital protuberance; ppi, postacetabular part of the ilium; prpi,
preacetabular part of the ilium; prz, prezygapophysis; psr, presacral rod; ptz, postzygapophysis; qjp, quadratojugal protuberance; ret, retroarticular
process; s, suture; sa, surangular; scv, sacrocaudal vertebra; spm, suture between premaxilla and maxilla; sr, sacral rib; sso, spike on sacral osteoderm;
sv, sacral vertebra; sy, symphysis; tp, transverse process; vg, ventral groove. Scale bar equals 5 cm.
The ventral part of the orbital rim (probably the jugal) is very
thin dorsoventrally, similar to that of Gastonia burgeri, and wider
mediolaterally in contrast with that of Struthiosaurus and Pawpawsaurus (Kirkland, 1998; Nopcsa, 1929; Lee, 1996, respec-
tively). The shape of the orbital rim is also more similar to that
of Gastonia than other nodosaurids. The postorbital protuberance forms a crest posterodorsal to the orbit in contrast with the
pyramidal-shaped horn of Pawpawsaurus and Gastonia (Blows,
2001).
Quadratojugal—No suture is recognizable between the jugal
and quadratojugal (Fig. 3). Due to the strong protuberance, the
quadratojugal of Hungarosaurus is more robust and wider dorsoventrally than that of Struthiosaurus. Its lower edge is rounded
similar to the invalid taxon, Hierosaurus sternbergii (Carpenter
et al., 1995).
Frontal—The ?left frontal (Fig. 2E, F) is pentagonal with
slight depressions (max. 0.5 cm) on the dorsal surface. The ventral surface is uneven, with a wide anterolateral suture for connecting to the prefrontal. A crest-like suture running on the
ventral surface anteroposteriorly could be the suture for the basicranium.
Palatal Region
FIGURE 3. Hungarosaurus tormai, gen. et sp. nov. (MTM Gyn/404,
holotype). A, left postorbital, jugal, and quadratojugal in lateral view; B,
posterior view. Scale bar equals 1 cm.
Vomer—The small, flat vomer (Fig. 4B) widens ventrally. Anteriorly the thin part of the vomer is wedged between the premaxillae, while the more posterodorsal, wider surface forms part
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of the palate. The concave posterior edges of the vomer and the
posterior part of the premaxillae form the anterior half of the
external nares.
Pterygoid—In posterior view, the pterygoid (Fig. 4A) is Vshaped and has a large interpterygoid vacuity like that of Pawpawsaurus and Euoplocephalus (Lee, 1996; Vickaryous and Russell, 2003). Anteriorly, the pterygoid is crushed towards the palatine, but on its ventral surface there is a strong medial septum
that divides the pterygoid into two concave surfaces. These surfaces are thinner transversely and the posterior margin of the
pterygoid is shorter laterally than those of Pawpasaurus.
Occipital Region
Quadrate—The quadrates (Fig. 5A, B, D) have a robust,
rhomboidal mandibular condyle, with a convex articular surface.
The sutural surface between the quadrate and quadratojugal as
in Struthiosaurus is not visible. This suggests a mature animal
(Pereda-Suberbiola and Galton, 2001). The lateral profile of the
quadrate is bowed, rostrally convex, and posteriorly concave.
The straight anterior edge of the quadrate forms the posterior
edge of the infratemporal fenestra. A small part of the ventral
edge of the posttemporal fenestra is visible on the mediodorsal
edge of the right quadrate. The pterygoid process is low on the
quadrate shaft. The contact with the squamosal is unknown.
Basioccipital—The hemispherical occipital condyle (Fig. 4C)
is broken and disarticulated, but the short neck that connects it
with the rest of the basicranium is visible.
FIGURE 5. Hungarosaurus tormai, gen. et sp. nov., (MTM Gyn/404,
holotype). A, left quadrate in posteroventral view; B, right quadrate in
posteroventral view; C, right quadrate condyle of Struthiosaurus austriacus (PIUW 2349/uncataloged C4b); D, right quadrate condyle of Hungarosaurus tormai, gen. et sp. nov. (MTM Gyn/404, holotype). Scale bar
equals 1 cm.
Mandibular Region
Dentary—The anterior part of the right dentary, the right
surangular, and the right angular are preserved (Fig. 6C–E). The
anterior end of the dentary curves medioventrally similar to that
of Struthiosaurus (Pereda-Suberbiola and Galton, 1994, 2001).
holotype). A, pterygoids in posteroventral view; B, vomer in lateral view;
C, occipital condyle in posteroventral view; D, hyoid; E, tooth in mesial
view; F, lingual view; G, other tooth in lingual view. Scale bar equals
1 cm.
The anterior part of the dentary has a grooved symphysis. In the
symphyseal region there are two large foramina, on the lateral
side of the dentary there are many foramina. Posteriorly from
the symphysis the dentary has a diastema that is sharp and suitable for cutting against the cutting margin of the premaxillae.
This cutting edge or diastema resembles that of the larger fragmentary dentary of Struthiosaurus (Pereda-Suberbiola and Galton, 2001:fig. 10.2o, p). The diastema is much shorter and taller,
thus more primitive than in Edmontonia, but longer and thus
more derived than that of Struthiosaurus sp. from Laño (PeredaSuberbiola, 1992; Pereda-Suberbiola et al. 1995, pers. comm.).
The dentary has seven or eight tooth positions without teeth. The
dentigerous part of the dentary tends to be taller posteriorly,
similar to that of other ankylosaur dentaries (Coombs and Maryanska, 1990). A groove that tapers anteriorly below the first
alveoli like that of Struthiosaurus (Pereda-Suberbiola and Galton, 2001) is present on the medioventral surface of the dentary.
It is slightly compressed, but could be the open Meckelian canal.
The sutural surface for a splenial is not visible; the latter is not
yet known for Hungarosaurus. By the fifth alveolus the dentary
is wider and does not have the same medial inclination from the
alveoli to the mandibular canal as does Struthiosaurus. Dorsolaterally, a shelf on the dentary widens posteriorly, similar to that
of Sarcolestes leedsi (BMNH 2682; Galton, 1983). This lateral
shelf is not as prominent in Struthiosaurus (PIUW 2349/5).
A small, lateral fragment of the right dentary is also preserved.
Because it preserves the lateral shelf with three large foramina,
similar to that of the larger dentary fragment, it could be the
middle or posterior part of the tooth row.
Surangular and Angular—The surangular and the angular are
also preserved (Fig. 6A, B). This part of the mandible has a
slightly concave ventral edge and is also slightly concave laterally. The dorsolateral wall of the external mandibular fenestra is
not complete; instead it is slightly crushed and moved ventrally.
Although the coronoid process is also damaged it is probably
low, similar to the condition in nodosaurids (Coombs and Maryanska, 1990). The external mandibular fenestra is closed. The
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FIGURE 6. Hungarosaurus tormai, gen. et sp. nov. (MTM Gyn/404, holotype). A, right surangular and angular in lateral view; B, medial view; C,
right partial dentary in lateral view; D, lingual view; E, dorsal view. Scale bar equals 5 cm.
lateral surfaces of the angular and the posterior part of the dentary bear a prominent elongated ornamentation with a definite
ventral edge. This ornamentation extends ventrally beyond the
characteristic medial edge of the mandible, similarly to that of
Edmontonia (Sternberg, 1928). The retroarticular process of the
surangular is very short and knob-like behind the articular surface for the quadrate condyle, but does not extend medially as in
Edmontonia. Instead, it is more like that of Sarcolestes in this
regard (Galton, 1983). The suture between the surangular and
angular is not visible.
Hyoid—One of the hyoid bones (Fig. 4D) is preserved. The
ends of the bone are missing, but its curvature is like that of
Panoplosaurus (AMNH 5381). In cross section the middle part is
flat and towards the ends it becomes more circular.
formation, it certainly would have been a wider than long cenrum in life. The transverse processes are short and project laterally. The neural spine is short, compressed anteroposteriorly,
and rounded dorsally. It is much shorter and wider mediolater-
Dentition
Teeth—Twenty-one isolated teeth (Fig. 4E–G) were collected,
of which 17 have relatively complete roots. These roots are two
to three times longer than the crowns and have a slight curvature
in mesial view. The crown of each tooth has an apex and a series
of secondary cusps along the mesial and distal edges of the crown
like other ankylosaur teeth (Coombs, 1990). There are six to
eight secondary cusps mesial and distal to the primary cusp.
Some of the secondary cusps have a very small “tertiary” cusp.
Two of the teeth are unworn and therefore can be considered
replacement teeth.
Postcranial Axial Skeleton
Cervical Vertebral Series—Three cervical vertebrae of Hungarosaurus are known from the cervical region (Fig. 7). They
have slightly amphycoelous centra and wide zygapophyses. Posteriorly the centra tend to be longer and the oval articular faces
of the proximal cervicals become rather circular in the more
posterior cervicals.
The first (Fig. 7A–C) is an anterior cervical vertebra (?fourth)
which is well preserved but strongly deformed; without this de-
holotype). A, ?fourth cervical vertebra in anterior view; B, left lateral
view; C, dorsal view; D, ?sixth cervical vertebra in anterior view; E, left
lateral view; F, dorsal view; G, ?eighth cervical vertebra in anterior view;
H, left lateral view; I, dorsal view. Scale bar equals 5 cm.
ally than the fourth cervical of Silvisaurus (Eaton, 1960). The
articular facet for the tuberculum is formed into a strong protuberance, similar to that of Struthiosaurus (Pereda-Suberbiola
and Galton, 2001). Cervical ribs were apparently not fused to the
vertebra, but are otherwise unknown.
The next cervical vertebra (?sixth) is nearly complete but also
deformed (Fig. 7D–F). Due to this deformation, the length/width
ratio of the centrum is difficult to estimate, but it was probably
as wide as long. The transverse processes are longer than on the
fourth cervical. The neural spine is damaged.
Only the neural arch of the third preserved cervical (?eighth)
is slightly compressed (Fig. 7G–I). The anterior face of the centrum is higher than the posterior face, as in Edmontonia, Ankylosaurus, and Talarurus (Eaton, 1960; Coombs and Maryanska,
1990). The centrum of this cervical is certainly longer than wide,
similarly to Struthiosaurus (Bunzel, 1871:pl. 2, figs 9, 10; PeredaSuberbiola and Galton, 2001). The postzygapophyses are closer
to each other than in proximal cervicals and they do not extend
posteriorly. Although the diapophyses are damaged, what is preserved of them indicates that they were in a higher position than
those of the more anterior cervicals.
Dorsal Vertebral Series—Six vertebrae and an isolated neural
arch represent the dorsal region of Hungarosaurus (Fig. 8). One
of the vertebrae (Fig. 8A–C) had an anterior position in the
dorsal column and might form the transition between cervical
and dorsal series. It has an unusally transversely wide, anteroposteriorly short amphycoelous centrum, with a strongly concave
posterior face that is larger than the anterior face; in addition,
the anterior face is higher than the posterior face. Because of its
strongly concave posterior face this vertebra was at the center of
the strong inclination between the cervical and dorsal series. This
feature is also mentioned in Edmontonia, Ankylosaurus, Saichania, and Pinacosaurus (Maryanska 1977; Vickaryous, pers.
comm.). This vertebra has a very large neural canal similar to
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other ankylosaurs (Makovicky, 1997). This type of vertebra is
not known in Struthiosaurus.
The diapophyses project laterally with a dorsal inclination of
approximately 15°. At the end of the diapophyses is an oval
articular surface for the tuberculum. The articular surface for the
capitulum is an oval depression on the lateral side of the centrum. The neural spine is broken, but its base is trapezoidal. In
the case of MTM Gyn/405., a complete anterior dorsal vertebra
indicates that the dorsal end of its column-like neural spine is
anteroposteriorly compressed. This specimen has shorter diapophyses and they have no dorsal inclination, in contrast with
that of MTM Gyn/404. The zygapophyses of MTM Gyn/404. are
wide mediolaterally. Many of these features strongly suggest that
the vertebra is the first dorsal or perhaps the last cervical.
The next five dorsals are all approximately equal in length and
their centra have slightly amphycoelous articular surfaces. The
ventral surfaces of the centra do not have keels, in contrast with
those of Struthiosaurus (Nopcsa, 1929:pl. 2, fig.13). One of the
dorsals (Fig. 8D–F) is slightly compressed transversely and the
neural arch is damaged, but the lateral sides of the base of the
neural arch have a flat oval protuberance for the articulation of
the capitulum, in contrast to the deep articular surface of Polacanthus foxi (Blows, 1987:fig. 1f). The diapophyses and complete
postzygapophyses are crushed. The diapophyses are short and
wide.
On the lateral parts of the centra of the remaining four dorsals,
there are no articular surfaces for the capitulum of the dorsal
ribs, indicating that these vertebrae come from the posterior
region of the dorsal series. Two of them (Fig. 8L–Q) have lost
their neural arches and are too compressed for detailed description. An isolated neural arch may pertain to one of these dorsals.
One of the two other dorsal vertebrae is also slightly compressed
and has a damaged neural arch (Fig. 8G, H). The diapophyses of
the well-preserved vertebra (Fig. 8I–K) are T-shaped in cross
FIGURE 8. Hungarosaurus tormai, gen. et sp. nov., (MTM Gyn/404, holotype). A, anterior dorsal vertebra with postzygapophyses in anterior view;
B, left lateral view; C, dorsal view; D, anterior dorsal vertebra (no neural spine or transverse processes) in anterior view; E, left? lateral view; F, dorsal
view; G, compressed anterior dorsal vertebra in anterior view; H, right lateral view; I, posterior dorsal vertebra in anterior view; J, left lateral view;
K, dorsal view; L, posterior dorsal vertebra without neural arch in anterior view; M, lateral view; N, dorsal view; O, posterior dorsal vertebra without
neural arch in anterior view; P, lateral view; Q, dorsal view. Scale bar equals 5 cm.
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section and have an upward inclination of approximately 30°, as
in other ankylosaurs (Coombs and Maryanska, 1990). The ribs
are fused to the diapophyses as in the posterior dorsals of other
ankylosaurs (Brown, 1908; Coombs and Maryanska, 1990). The
neural spines are broken but have antero-posteriorly elongate
bases. The prezygapophyses are small and close to each other.
The dorsal ribs are T-shaped in cross section, similar to those
of Polacanthus and Struthiosaurus.
Sacral Vertebral Series—The sacrum of MTM Gyn/404. is
crushed and mostly missing, but MTM Gyn/407. has a nearly
complete sacrum (Fig. 9), consisting of nine fused vertebrae,
including five dorsals (or four dorsals and one dorsosacral)
formed into the presacral rod and four sacral vertebrae. The ribs
of the presacral rod and almost the complete neural arches of the
second, fourth, and fifth dorsals are crushed. The last (fifth)
dorsal is wider than the other dorsals. The sacral vertebrae are
very wide, flat, and completely fused with the short sacral ribs.
The thin sacral ribs of the first sacral vertebra are all horizontal
and have anteroposteriorly-expanded dorsal edges. Their Tshaped cross section is reminiscent of the true dorsal ribs. The
second pair of sacral ribs is the widest, with strong proximal and
distal expansions. The third pair of sacral ribs is similar, but more
slender. On the ventral surfaces of the last dorsal and first sacral
vertebrae, there is a shallow groove, similar to that of Struthiosaurus languedocensis (Garcia and Pereda-Suberbiola, 2003).
The ribs of the last vertebra of the sacrum are crushed and the
vertebra (which may be a sacrocaudal) is also damaged, but it
does have separate postzygapophyses.
Caudal Vertebral Series—Two proximal (Fig. 10A–F), two
middle (Fig. 10G–L) and six distal caudal vertebrae (Fig. 10M–
D’) were discovered in the assemblage. The proximal caudals
FIGURE 9. Sacrum of Hungarosaurus tormai, gen. et sp. nov. (MTM
Gyn/404, holotype). A, dorsal view; B, ventral view. Scale bar equals
5 cm.
(?first and second) are very similar to those of Struthiosaurus
(Nopcsa, 1929:pl. 3, Fig. 3–4.) in having short amphycoelous centra. On the ?first caudal vertebra the anterior face is smaller than
the posterior face. The prezygapophyses extend strongly anteriorly, similar to those of the first caudal of Euoplocephalus tutus
(Coombs and Maryanska, 1990) or the caudals of Struthiosaurus
(Pereda-Suberbiola and Galton, 2001:fig. 10.3j, k).
Only the two vertebrae of the middle portion of the tail bear
a ventral groove. Their amphicoelous centra have short thornlike transverse processes.
The distal caudal vertebrae are also amphycoelous and have
no transverse processes. Their centra have hexagonal articular
surfaces and longitudinal ridges laterally, similar to Struthiosaurus (Pereda-Suberbiola and Galton, 2001:fig. 10.3). Notochordal
protuberances in the middle of the faces of the centra are present
only by the distal caudals.
Five isolated chevrons are presently known for Hungarosaurus. They represent all the types of forms of the haemal arch. The
most proximal chevron is long and straight ventrally, while more
caudally they tend to be shorter and their distal ends project
anteriorly. More caudal still, they are much shorter and hatchetshaped, as in the case of Hylaeosaurus (BMNH 3789). One of the
chevrons is fused with the centrum of a distal caudal vertebra,
similar to the condition in Struthiosaurus (Pereda-Suberbiola
and Galton, 2001:fig. 10.3y).
Appendicular Skeleton
Scapulocoracoid—The left scapulocoracoid (Fig. 11B), the
right scapula (Fig. 11A) and the anterior part of the right coracoid are known from Hungarosaurus and represent the first
known complete scapulocoracoid of an Upper Cretaceous ankylosaur from Europe. The curvature of the scapular blade is very
similar to the best-preserved scapula of Struthiosaurus (Bunzel,
1871:pl. 5, fig. 7–8, Pereda-Suberbiola and Galton, 2001:fig.
10.4a, b). The end of the acromion process is crushed in both
specimens, but it clearly projects toward the insertion surface for
M. supracoracoideus anterior instead of toward the central area
of the glenoid, as in Sauropelta (Ostrom, 1970; Galton, 1983;
Coombs, 1995). Extending from the dorsal edge of the scapular
blade, the acromion process of Hungarosaurus is developed
slightly more dorsally than that of Struthiosaurus (Nopcsa, 1929;
Pereda-Suberbiola and Galton, 2001:fig. 10.4a, b).
The scapula is completly fused with the coracoid. The latter is
relatively large when compared to the scapula, as in other nodosaurids, and it is very similar in morphology to the coracoid of
Sauropelta (Coombs, 1978). The posterior part of the area for M.
supracoracoideus anterior on the scapular blade abruptly widens, as in Sauropelta and small individuals of Struthiosaurus
(Coombs, 1978:fig. 8; Pereda-Suberbiola and Galton, 2001:fig.
10.4f, g). This part of the scapulocoracoid is two times thicker
than the other parts. The edge of the coracoid is very thin and
has two grooves for muscle scar, similar to the condition in Sauropelta (Coombs, 1978:fig. 8). The ventral edge of the coracoid is
rugose and scalloped for articulation with the sternum and the
ventral part of the coracoid is thicker than anteriorly. The posteroventral edge of the coracoid has a concave surface, being
deeper towards the glenoid. This deep surface and the robust,
grooved knob at the end of the coracoid are for the M. costocoracoideus. The supracoracoideus fossa is large and situated
anteriorly to the glenoid, like that of Panoplosaurus (Galton,
1983).
The medial part of the right scapula is damaged next to the
glenoid. The right coracoid is missing; only its anterior part is
preserved. Because of differential crushing, the width of the
glenoid is different on the right scapula and on the partial right
coracoid.
377
FIGURE 10. Hungarosaurus tormai, gen. et sp. nov. (MTM Gyn/404, holotype). A, ?first caudal vertebra in anterior view; B, left lateral view; C,
dorsal view; D, ?second caudal vertebra in anterior view; E, left lateral view; F, dorsal view; G, middle caudal vertebra in anterior view; H, left lateral
view; I, dorsal view; J, middle caudal vertebra in anterior view; K, lateral view; L, dorsal view; M, P, S, V, Y, B’, posterior caudal vertebrae in anterior
view; N, Q, T, W, Z, C’, lateral view; O, R, U, X, A’, D’, dorsal view. Scale bar equals 5 cm.
Ulna—The ulnae of the holotype were not found. However,
MTM Gyn/406. preserves the proximal part of an only slightly
compressed ?right ulna (Fig. 11E). The oleocranon is not particularly massive and does not project well above the humeral
articular facet, like the condition seen in Sauropelta (Ostrom,
1970).
Radius—The right radius (Fig. 11C, D) is straight in anterior
view and had an oval shape in cross section, like that of Texastes
pleurohalio (Coombs, 1995). The distal end and the posterior
edge of the radius are crushed. The proximal articular surface is
also oval and slightly concave for reception of the radial condyle
of the humerus, similar to that of Texastes (Coombs, 1995:fig. 5c).
On the anterior side, there is a knob for M. biceps supracoracoideus and for M. brachialis (Coombs, 1978), which is situated
more distally than in Sauropelta (Coombs, 1978).
Metacarpals—Four metacarpals were originally found at the
distal end of the radius described above (Fig. 11F–I). One has a
partially proximal end, but all of the ends of the others are
abraded worn away. The proximal and distal ends of each metacarpal are strongly divergent.
Phalanges—One proximal or middle phalanx (Fig. 11L, M)
and an ungual (Fig. 11J, K) are known, but were not found in
articulation or associated with the above mentioned metacarpals.
The proximal/middle phalanx is wider than long. Based on the
comparison of this phalanx with those of Sauropelta, it could be
the first phalanx of a digit. The ungual is nearly twice as long as
wide and probably the longest element of the phalangeal set,
similar to the condition in nodosaurids (Coombs and Maryanska,
1990).
Ilium—Only two parts of the preacetabular region of the left
ilium, a small preacetabular part of the right ilium, and the left
ischium are known from the pelvic girdle of MTM Gyn/404.
However, the left ilium (Fig. 12A, B) and the ischia of MTM
Gyn/407. are preserved separately; they are nearly complete.
The anterior ends of the ilia are missing. The lateral edge of the
ilium is thicker than the medial part. The shaft of the ilium is less
S-shaped than that of S. languedocensis (Garcia and PeredaSuberbiola, 2003). Nopcsa (1929:40) pointed out that the knob
on the ventral surface of the ilium of Struthiosaurus in fact is the
upper part of the pubis. In the case of the right ilium of MTM
Gyn/404., this fragmentary, conical element is crushed, but preserved in an allochtonous situation. The postacetabular part of
MTM Gyn/407. is short, bearing a protuberance in its center.
Ventrally the acetabular region of MTM Gyn/407. is worn, and
the acetabulum is not visible. Although the dorsal surfaces of the
ilia are damaged, no traces of coossified dermal elements are
recognizable.
Ischium—The body of the ischium (Fig. 12C, D) is long, laterally compressed, and slightly curved anteriorly. This curvature
is slighly greater than that of Struthiosaurus (Garcia and PeredaSuberbiola, 2003), but less than that of Sauropelta (Ostrom,
1970). The distinct flexion of ischia seen in Sauropelta (Coombs,
1979) is not present, as is also the case in Struthiosaurus (Garcia
and Pereda-Suberbiola, 2003). No knob-like structure is present
at the distal end of the ischia of the MTM Gyn/404. and MTM
Gyn/407. in contrast to that of Struthiosaurus (Garcia and Pereda-Suberbiola, 2003), but it is flat and pointed.
Femur—The right femur (Fig. 12E, F) is complete but compressed anteroposteriorly, like that of Polacanthus (BMNH
R.175). Due to this deformation, it is uncertain whether the shaft
is curved in lateral view. The greater trochanter is lower like that
in Hoplitosaurus marshi and in Edmontonia and is not very separated from the anterior trochanter as in Sauropelta and in Cryptodraco (Carpenter et al., 1995). The fourth trochanter is flat and
rugose, with a slightly convex surface; it is located proximally,
but near the midlength of the femur.
Fibula—The right fibula (Fig. 12G–I) is very thin and well
preserved. It is straight anteriorly and has a slight curvature
laterally. The distal end is rotated approximately 45° to the long
axis of the proximal end. The anterior edge of the proximal end
expands strongly and the insertion surface for M. iliofibularis is
smaller than that of Struthiosaurus (Pereda-Suberbiola and Gal-
378
ton, 2001:fig. 10.7o–r). The articular surface for the tibia on the
posterior surface of the distal fibula (approximately 1/5 the
length of the fibula) is highly striated. The distal articular surface
for the calcaneum is present, suggesting that the calcaneum was
not fused with the fibula. The fibula-femur ratio is approximately
0.77, which indicates that Hungarosaurus had a long lower leg,
much like Nodosaurus textilis or Niobrarasaurus coleii (Table 1;
Ford and Kirkland, 2001).
Armor
holotype). A, right scapula in lateral view; B, left scapulocoracoid in
lateral view; C, right radius in lateral view; D, anterior view; E, ulna
(MTM Gyn/406., paratype) in ?lateral view; F–I, metacarpals; J, ungual
in extensor view; K, lateral view; L, middle phalanx in extensior view M,
lateral view. Scale bar equals 5 cm.
More than a hundred elements of the disarticulated armor
were discovered; they belong to at least five types.
Cervical and Shoulder Region—Armor from the cervical and
shoulder regions consists of two rows of posteriorly projected
plates. In these rows, the first coossified elements are quarterrings, which have a tall keel laterally and a lower keel laterodorsally. The lower keel is situated also more posteriorly than the
taller keel. Between these keels, the plates have a grooved dorsal
surface. The edge of the base of this element is indented, maybe
for better stabilizing of the plate. This type of fused osteoderms
is also seen in Struthiosaurus, but it is much smaller (Nopcsa,
1929; Pereda-Suberbiola et al., 1995; Pereda-Suberbiola and Galton, 2001). The ?second quarter-ring in the row (Fig. 13A) has a
single tall keel and a narrower plate lacking a substantial lower
keel that extending posterodorsally. Instead, a trace of the lower
keel appears as a ridge on the ventral surface. Posteriorly, the
next plates have a single keel that tends to be smaller than the
more anterior quarter-ring plates. The ?last/fifth element (Fig.
13B; position based on its size) has only a small keel and a short,
posterodorsally extending plate without a lower keel. These
quarter-rings and plates are situated in a group at the front of the
skeleton at the excavation site.
Dorsal and Sacral Region—The dorsal region was covered by
low-keeled osteoderms (Fig. 13D, E), larger circular scutes with
low ridges that end in knobs, and much smaller oval or circular
osteoderms (Fig. 13G). The low-keeled osteoderms—the most
ubiquitous elements of the armor—covered most of the dorsum
of the body and they are usually oval or rhomboidal (Coombs
and Maryanska, 1990). Many circular osteoderms were discovered near the parts of the pelvic girdle, suggesting that they also
FIGURE 12. Hungarosaurus tormai, gen. et sp. nov. (MTM Gyn/404, holotype), and (MTM Gyn/407, paratype). A, right ilium (MTM Gyn/407.,
paratype) in ventral view; B, dorsal view; C, left ischium (MTM Gyn/407., paratype) in lateral view; D, anterior view; E, femur in medial view; F,
posterior view; G, right fibula in lateral view; H, medial view; I, articular surface on the distal end of the fibula. Scale bar equals 5 cm.
379
TABLE 1. Measurements of skeletal elements of Hungarosaurus tormai, gen. et sp. nov. HNHM Gyn/404, HNHM Gyn/406 and HNHM
Gyn/407. C, cervical vertebra; D, dorsal vertebra; CA, caudal vertebra.
In the case of the vertebrae the maximum length is for the centrum.
Skeletal elements
Maximum length (cm)
C-4
C-6
C-8
D-a
D-b
D-c
D-d
D-e
D-f
Sacrum
CA-a
CA-b
CA-c
CA-d
CA-e
CA-f
CA-g
CA-h
CA-i
Ca-j
Left scapulocoracoid
Right scapula
Ilium
Ischium
Right femur
Right fibula
Right radius
?Right ulna
4.4
5.2
7.1
3.9
5.6
5.6
6.3
6.7
7.3
54 (HNHM Gyn/407)
3.5
3.7
5.3
5.2
5.7
5.6
5.6
5.5
4.9
5.1
52
32
Damaged
26 (HNHM Gyn/407)
47
35
26.5
Damaged
(HNHM Gyn/406)
Damaged
Damaged
Damaged
Damaged
2.9
6.4
Mtc. I
Mtc. II
Mtc. III
Mtc. IV
Prox. phalanx
Ungual phalanx
even covered the posterior part of the dorsum and sacrum. The
smallest osteoderms, which have no dorsal ridges and often have
convex bases, probably filled the remaining spaces between the
plates and the low-keeled and circular osteoderms.
The sacrum and the ilia were covered by a large (38 cm transversly), crescentic, fused sacral plate recovered only in MTM
Gyn/407. (Fig. 13H). It is symmetrical transversely and bears two
robust, cone-shaped spikes with circular cross-section. On the
sacral plate only the bases of these spikes are preserved; the tips
are crushed and only one of the tips was found separately. This
tip is slightly compressed. Probably the convex edge of the plate
was situated anteriorly; thus, the spikes had a posterodorsal direction. This spike is similar to that of Struthiosaurus (PIUW
2349/15 A1a). Anterolaterally on the dorsal surfaces of this sacral element on both sides, a crest-like protuberance is preserved
and two ridges (maybe the sutures of the fused sacral elements)
run posterolaterally. Both the dorsal and ventral surfaces of the
plate are grooved and rugose.
Caudal Region—Dorsolaterally on the tail, hollow-based,
keeled osteoderms (Fig. 13C) form two rows; these are relatively
smaller than the aforementioned plates, similar to those of
Struthiosaurus, Polacanthus, and Gastonia (Nopcsa, 1929; Blows,
1987; Pereda-Suberbiola and Galton, 2001; Gaston et al., 2001).
Smaller circular osteoderms that covered the tail between the
plates are similar to the condition in Hylaeosaurus (BMNH
3789).
Limb Region—Slightly concave, rhomboid elements (Fig.
13F) are thought to be the armor elements of the limbs. These
compare very well with similar but much larger osteoderms,
found near the ulna and radius of Sauropelta (AMNH 3032).
FIGURE 13. Hungarosaurus tormai, gen. et sp. nov., (MTM Gyn/404,
holotype). A, left cervical-pectoral quarter-ring in lateral view; B, ?last/
fifth element of the cervical-pectoral quarter-ring row in dorsal view; C,
caudal dermal plate in lateral view; D, E, dermal scutes of the dorsal
region; F, dermal scute of the limb region; G, small dermal ossicle; H,
sacral plate of MTM Gyn/407. in dorsal view. Scale bar equals 5 cm.
PHYLOGENETIC RELATIONSHIPS
To determine the phylogenetic position of Hungarosaurus
within the Ankylosauria, a preliminary cladistic analysis involving 16 ankylosaur taxa (including Hungarosaurus; see Appendix
1) and one outgroup was undertaken. Except for Struthiosaurus,
Pawpawsaurus, and Gobisaurus, all the nodosaurid and ankylosaurid taxa were selected on the presence of well-preserved cranial and postcranial material. Struthiosaurus should be in the
analysis, because it is the only known Late Cretaceous ankylosaur from Europe. Although Pawpawsaurus and Gobisaurus
lack postcranial material, they possess a fully complete cranium
with detailed description and phylogenetic analysis (Lee, 1996;
Vickaryous et al., 2001). Scelidosaurus is the only outgroup in the
analysis. All 63 cranial and postcranial characters (Appendix 1)
in the cladistic analysis are adapted completely from Vickaryous
et al. (in press). They are unordered, all having equal weight. The
resulting data matrix (Appendix 2) was analysed using the heuristic search algorithm of Phylogenetic Analysis Using Parsimony (PAUP) version 4. (Swofford 1998).
RESULTS AND DISCUSSION
Two analyses were run with the 17 taxa. The first one used the
complete character list (63 characters). The second analysis used
380
only the first 41 cranial characters. The 41 characters used are
nearly the same as those in Vickaryous et al. (2001); only number
24 was modified in Vickaryous et al. (in press).
In the first case the analysis of the data matrix resulted in 6
parsimonious trees of 150 steps, CI⳱0.506, HI⳱0.493,
RI⳱0.676, RC⳱0.342. The strict consensus tree is presented in
Fig. 14. The analysis corroborates the thesis that Gargoyleosaurus and Minmi are basal taxa within the clade of Ankylosauridae
(Sereno, 1998, 1999; Vickaryous et al., 2001; Vickaryous and
Russell, 2003). On the consensus tree the ‘traditional’ nodosaurids (Vickaryous et al. 2001) show polytomy.
Presence of ornamentation on the cranial elements, the ankylosed ribs with the posterior dorsal vertebrae (Brown, 1908), and
the solid armor composed of multiple parasaggital rows of osteoderms on the cervical and shoulder region (character 49) filling the spaces between larger plates with small osteoderms
(Sereno, 1999) clearly characterize Hungarosaurus as a member
of the Ankylosauria. The analysis result is that Hungarosaurus
appears to be a nodosaurid.
The second analysis with only the first 41 cranial characters
(Appendix 2) gave one parsimonious tree of 102 steps,
CI⳱0.480, HI⳱0.519, RI⳱0.712, RC⳱0.342. This tree is presented in Fig. 15. It shows that Struthiosaurus seems to be one of
the most basal ankylosaurs in the monophyletic clade of the
Ankylosauria (node 1), in spite of its youngest (Campanian–
Maastrichtian) age. Hungarosaurus is diagnosed by a suite of
apomorphic (e.g., protuberances on temporal bones, ornamentation on premaxillae, presence of a large premaxillary notch)
and plesiomorphic (e.g. presence of premaxillary teeth) character states. This cladogram illustrates that Hungarosaurus is a
basal nodosaurid. It appears to be more derived than Struthio-
FIGURE 15. Phylogenetic hypothesis of the Ankylosauria using only
cranial characters (characters 1–41; Vickaryous et al., in press). The only
parsimonious tree (102 steps, CI⳱ 0.480, HI⳱0.519, RI⳱0.712,
RC⳱0.342) illustrates that Hungarosaurus is a basal nodosaurid. Explanation of nodes: node (1) Ankylosauria; node (2) Ankylosauridae; node
(3) Nodosauridae; node (4) Ankylosaurinae.
saurus, but more primitive than the North American taxa Pawpawsaurus, Sauropelta, Silvisaurus, Edmontonia, and Panoplosaurus.
Nevertheless, it is important to note that the determinable
characters (44% of the total character list: 33% of the cranial and
62% of the postcranial charachters) are very few in the case of
Hungarosaurus; thus this statement awaits subsequent testing.
CONCLUSIONS
FIGURE 14. Phylogenetic hypothesis of the Ankylosauria. A strict
consensus tree of 6 parsimonious cladograms (150 steps each, CI⳱0.506,
HI⳱0.493, RI⳱0.676, RC⳱0.342) obtained from a matrix containing 63
characters (Vickaryous et al., in press) for one outgroup and 16 ingroup
taxa. In this analysis Hungarosaurus appears to be a nodosaurid. Explanation of nodes: node (1) Ankylosauria; node (2) Ankylosauridae; node
(3) Ankylosaurinae.
Hungarosaurus tormai, gen. et sp. nov., from the Santonian of
Hungary is the most complete ankylosaur presently known from
the Upper Cretaceous of Europe. It is characterized by a large
notch at the front of premaxillae, a very short retroarticular
process of the surangular, and an anterior dorsal vertebra with
an unusual transversely wide, anteroposteriorly short amphycoelous centrum, with a very large neural canal. Hungarosaurus is
clearly distinguishable from Struthiosaurus, the other European
Late Cretaceous taxon on the basis of the dorsoventrally wide
quadratojugal, the presence of bony protuberances on the
quadratojugal and postorbital, the robust mandibular quadrate
condyle, and the interpterygoid vacuity. The cladistic analyses
suggest that Hungarosaurus is a basal nodosaurid and appears to
be more derived than Struthiosaurus, but more primitive than
the North American Silvisaurus, Sauropelta, and Pawpawsaurus.
The large abundance (totaling more than 600 bones: four partial skeletons and many isolated elements) of armored dinosaur
bones is an unique feature of the Santonian Iharkút locality compared with other European Late Cretaceous vertebrate localities.
ACKNOWLEDGMENTS
I am especially grateful to the Bakony Bauxite Mining Company for their logistical help and to A. Torma, L. Makádi, F.
Szőke, C. M. Jianu, D. B. Weishampel, L. Kocsis, E. Gáspár, M.
Rabi, A. Prohászka, T. Pocsai, Sz. Simon, A. Pászti, E. Gulyás,
and Zs. Benkó for field assistance. I thank C. M. Jianu and D. B.
Weishampel for our contribution over the last two years. I am
thankful to Sandra Chapman and Angela Milner (BMNH),
Norbert Vávra (PIUW), Carmelo Corral (MCNA), Xabier Pereda-Suberbiola (Universidad del Paı́s Vasco Bilbao, Spain), Sylvain Duffaud and Jean Le Loeuff (MDE), Ivy Rutzky, Judy
Galkin and Carl Mehling (AMNH), Michael K. Brett-Surman
(USNM) and Kenneth Carpenter (Denver Museum of Nature
and Sciences, Denver, USA) for access to material in their care.
I thank David B. Weishampel, Eric Buffetaut and Kenneth Carpenter for helpful discussions. I wish to thank David B.
Weishampel, Kenneth Carpenter, Ágnes Görög and László
Makádi for reading the first draft of the manuscript. I am especially grateful to Matt Vickaryous and Xabier Pereda-Suberbiola
for making significant improvements to the text and to Matt
Vickaryous for useful consultations. In addition, I thank the
Hungarian Natural History Museum, the Hungarian Academy of
Sciences, Research Group for Palaeontology, the National Geographic Society (Grant Numbers 7228–02; 7508–03), the Pro
Renovanda Cultura Hungariae Foundation, and the Hungarian
National Scientific Research Foundation (OTKA T-38045) for
supporting the Iharkút dinosaur project.
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APPENDIX 1
Characters in the Phylogenetic Analyses used after Vickaryous et al.
(in press).
(1) Maximum cranial dimension: cranium length greater than
cranial width (0); cranial width equal to or greater than
cranial length (1)
(2) Cranial roof in lateral profile rostral to orbits: flat (0);
dome-like (1)
(3) Cranial roof in lateral profile caudal to orbits: flat (0);
dome-like (1)
(4) Laterotemporal fenestra in lateral view: open (0); closed (1)
(5) Supraorbital boss: absent (0); present, rounded protuberance, laterally oriented (1); present, longitudinal ridge, dorsolaterally oriented (2)
(6) Squamosal boss: absent (0); present, rounded protuberance
(1); present, pyramidal protuberance (2)
(7) Quadratojugal projection: absent (0); present, rounded protuberance (1); present, deltaic protuberance (2)
(8) Cranial ornamentation in a transverse plane across the rostral region: absent (0); present, amorphous/ill-defined (1);
present, distinct pattern of sculpturing consists of three or
more flat polygons (2); present, distinct pattern of sculpturing consists of three or more bulbous polygons (3); present,
distinct pattern of sculpturing consists of one or two flat
polygons (4)
(9) Shallow furrows demarcate a single area of cranial ornamentation between the external nares: absent (0); present
(1)
(10) Skull table morphology: width between squamosals greater
than or equal to width between supraorbitals (0); width
between squamosals less than width between supraorbitals
(1)
(11) Raised nuchal sculpturing: absent (0); present (1)
(12) Nuchal shelf: does not obscure occiput in dorsal view (0);
obscures occiput in dorsal view (1)
(13) Maximum premaxillary rostrum dimension: premaxillary
palate length equal to or greater than premaxillary palate
width (0); premaxillary palate length less than premaxillary
palate width (1)
(14) Maximum premaxillary rostrum width: less than the distance between the caudal-most maxillary teeth (0); equal to
or greater than the distance between the caudal-most maxillary teeth (1)
(15) Premaxillary notch: absent (0); present (1)
(16) Premaxillary tomia: restricted to an extreme rostral position (0); extend caudally, continuous with maxillary tooth
row (1); extends caudally, lateral to maxillary tooth row (2)
(17) Premaxillary teeth: present (0); absent (1)
(18) Maxillary tooth rows: linear rostrally, diverge caudally (0);
curved into an hourglass-shape, diverge rostrally and caudally, converge midway along the tooth row (1)
(19) Post-premaxillary tooth cingulum: absent (0); present (1)
(20) Longitudinal bisection of the rostrum by the internasal cavity septum: incomplete (0); complete, (1)
(21) Secondary palate: absent (0); rostrodorsal palatal arch only
(1); rostrodorsal and caudoventral palatal arches (2)
(22) Buccal emargination: flat (0); strongly concave (1)
(23) External naris proper: not visible in rostral view (0); visible
in rostral view (1)
(24) Intranasal septum segregating nasal aperture from paransal
aperture visible: absent (0); present (1)
(25) Nasal cavity proper: relatively linear orientation (0); convoluted (1)
(26) Paranasal sinus cavities: absent (0); present (1)
(27) Rostral face of pterygoid body: directed caudally (0); directed vertically or rostrally (1)
(28) Caudal margin of the pterygoid: rostral to (0); or in transverse alignment with (1) the ventral margin of the pterygoid
process of the quadrate
(29) Mandibular ramus of the pterygoid: directed parasagittally
(0); rostrolaterally (1)
(30) Basipterygoid process - pterygoid contact: fused (0); unfused (1)
(31) Basisphenoid length: greater than basioccipital length (0);
less than basioccipital length (1)
(32) Basal tubera morphology: bulbous (0); rugose crest (1)
(33) Paroccipital process directed: caudolaterally (0); laterally
(1)
(34) Occipital condyle composition: multiple elements (0); basioccipital only (1)
(35) Occipital condyle morphology in occipital view: reniform
(0); ovoid / round (1)
(36) Occipital condyle orientation: directly caudally (0); caudoventrally (1)
(37) Foramen magnum orientation: directly caudally (0); caudoventrally (1)
(38) Quadrate lateral profile: bowed, rostrally convex, caudally
concave (0); linear (1)
(39) Quadrate - paroccipital process contact: unfused (0); fused
(1)
(40) Quadrate condyle, lateral view: visible (0); obscured by the
quadratojugal (1)
(41) Postocular shelf: absent (0); present (1)
(42) Antorbital fenestra: present (0); absent (1)
(43) Dorsotemporal fenestra: present (0); absent (1)
(44) External mandibular fenestra: present (0); absent (1)
(45) Ornamentation on angular: absent (0); present (1)
(46) Atlas and axis: separate (0); fused (1)
(47) One or more postaxis cervical centra in profile: cranial and
caudal ends parallel and aligned (0); cranial and caudal
ends parallel, cranial end dorsal to caudal end (1); cranial
and caudal ends parallel, caudal end dorsal to cranial end
(2)
(48) Fusion of dorsal ribs to centra: absent (0); present (1)
(49) Multiple parasagittal rows of osteoderms on dorsal surface
of neck region: absent (0); present, fused together (1); present, fused to quarter/half ring (2)
(50) Multiple parasagittal rows of post cervical osteoderms: absent (0); present (1)
(51) Tail club: absent (0); present (1)
(52) Acrominon: absent (0); present, crest at cranial margin (1);
present, blade-like flange perpendicular to long axis (2);
present, knob-like process (3)
(53) Ventral border of coracoid in profile: rounded (0); straight
(1)
(54) Length of deltopectoral crest relative to humerus: less than
50% (0); approximately equal to or greater than 50% (1)
(55) Distal margin of iliac blade: oriented vertically (0); forms a
horizontal shelf dorsal to the acetabulum (1); partially encircles the acetabulum laterally (2)
(56) Acetabulum: open (0); closed (1)
(57) Shaft of ischium: little to no curvature (0); pronounced curvature (1)
(58) Pubis contribution to acetabulum: one quarter or more (0);
virtually excluded (1)
(59) Ossified tendons in region of tail: absent (0); present (1)
383
(60) Bilateral sternal element contact: not fused (0); fused (1)
(61) Synsacrum of coossified dorsal, sacral and caudal vertebrae:
absent (0); present (1)
(62) Ornamentation on premaxillae: absent (0); present (1)
(63) Maxillary tooth rows inset from lateral edge of maxilla
(emarginated): absent (0); present (1)
APPENDIX 2
Character-taxon matrix used for phylogenetic analyses.
APPENDIX 2
Character-taxon matrix used for phylogenetic analyses.
Taxon
12345
1
67890
11111
12345
11112
67890
22222
12345
22223
67890
33333
12345
33334
67890
44444
12345
44445
67890
55555
12345
55556
67890
666
123
Scelidosaurus
Struthiosaurus
Pawpawsaurus
Hungarosaurus
Edmontonia
Silvisaurus
Sauropelta
Panoplosaurus
Minmi
Euoplocephalus
Ankylosaurus
Gargoyleosaurus
Gastonia
Gobisaurus
Pinacosaurus
Saichania
Shamosaurus
00000
??100
00101
???02
00101
01101
00101
00100
00011
11012
11012
00000
01000
00010
10012
10012
10012
00000
00??1
22111
?1?0?
01411
01101
011?1
01411
22??0
22200
22210
22101
22101
11100
22??0
22300
11200
0000?
00???
10000
??0?1
00000
00000
00???
10000
?0?01
11111
11111
10101
10111
00011
?1111
11101
00001
?0010
?????
00110
1001?
11111
00011
???1?
1111?
2001?
21101
21001
00000
2100?
21011
21010
21010
210?1
00??0
?????
00000
0?0??
10000
0000?
?????
1?00?
?????
21111
210?1
01000
10100
20110
21111
2?111
2011?
?????
?????
00100
??0??
1110?
?0101
????1
?010?
??0??
11111
10111
?101?
??110
11011
11010
11010
?0010
1????
??010
10011
????0
?1011
101?1
?0011
?1011
1?000
11110
11110
??0?0
10100
?11?0
11100
11110
?1??0
??0?0
00110
00010
??0??
1?010
00011
100?0
01010
001??
11101
11111
??010
111?0
11110
10?01
11?11
1?110
?0011
??1??
?11??
???11
01111
?1111
?1111
01111
?111?
11111
1111?
?1111
?11??
111??
11111
11111
11111
11?00
0012?
?????
?1121
11121
?1021
01020
1101?
???20
01121
?1101
?1?2?
???20
?????
0?121
12121
??1??
00000
?3?0?
?????
030??
03111
?????
03011
?301?
03?01
11112
10?1?
?????
02?12
?????
11?11
11?1?
?10??
0000?
1010?
?????
10???
111?1
?????
1111?
????1
00?1?
10111
?0?0?
?????
111??
?????
10?11
????1
?????
000
1??
?01
11?
111
101
1?1
111
111
101
?11
?11
101
?11
?11
?11
?01

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