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New specimens, including a growth series, of Fukuiraptor (Dinosauria, Theropoda) from the Lower Cretaceous Kitadani Quarry of Japan


Abstract and Figures

In addition to the holotype skeleton of Fukuiraptor kitadaniensis, isolated teeth and bones of the same taxon have been collected from the Kitadani Quarry of the Lower Cretaceous (Barremian) strata in Fukui Prefecture, Japan. These provide additional information that help determine its phylogenetic position, and also represent a growth series. The holotype is an immature specimen, which was about 4.2 meters long. Other fossils from the same quarry are all from smaller individuals. Some of the juvenile bones are less than a third the linear length of equivalent bones in the holotype.
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J. Paleont. Soc. Korea. Vol. 22, No. 1, (2006) : p. 173-193
Philip J. Currie1 and Yoichi Azuma2
1University of Alberta, Department of Biological Sciences, 11145 Saskatchewan Drive, Edmonton,
Alberta T6G 2E9, Canada,
2Fukui Prefectural Dinosaur Museum, 5-11 Terao, Muroko, Katsuyama, Fukui 911-8601, Japan
Abstract: In addition to the holotype skeleton of Fukuiraptor kitadaniensis, isolated teeth and bones of the same
taxon have been collected from the Kitadani Quarry of the Lower Cretaceous (Barremian) strata in Fukui
Prefecture, Japan. These provide additional information that help determine its phylogenetic position, and also
represent a growth series. The holotype is an immature specimen, which was about 4.2 meters long. Other fossils
from the same quarry are all from smaller individuals. Some of the juvenile bones are less than a third the linear
length of equivalent bones in the holotype.
Key words: Fukuiraptor, growth series, Kitadani, Japan
The Kitadani Quarry is on the Sugiyama River within the city limits of Katsuyama in Fukui
Prefecture, Japan. It is the largest dinosaur excavation that has been done in Japan, and is arguably one of
the largest dinosaur quarries in the world. Worked originally by the Fukui Prefectural Museum between
1988 and 1993, and from 1996 to 1998, the excavation is being continued by the Fukui Prefectural
Dinosaur Museum, which opened in 2000.
The excavation has produced bones, eggshell and footprints of theropods, sauropods and ornithischians.
Other fossils recovered from the site include plants, freshwater mollusks, fish, turtles, crocodiles and
birds (Azuma et al., 1995). The best specimens from the quarry include a nearly complete goniopholidid
crocodyliform (Kobayashi, 1998), the iguanodontians Fukuisaurus tetoriensis (Kobayashi and Azuma,
2003) and the carnosaurian theropod Fukuiraptor kitadaniensis (Azuma and Currie, 2000).
The type material of Fukuiraptor kitadaniensis represents an immature individual that was about 4.2
meters long at the time of death. Most of the other theropod teeth and bones from the same quarry are
from smaller individuals of the same taxon. Some of the juvenile bones are less than a third the linear
length of equivalent bones in the holotype. In this paper, we have focused on teeth, humeri and femora
because these are the most diagnostic elements that are well represented by multiple specimens. There
are additional bones from the quarry that probably represent Fukuiraptor. However, they lack diagnostic
Fukuiraptor characters, and/or they do not add significant information to the previous description
(Azuma and Currie, 2000), and/or they do not provide information about growth in this taxon.
THEROPODA Marsh, 1881
J. Paleont. Soc. Korea. Vol. 22, No. 1, 2006
Tabl e 1 . Teeth of Fukuiraptor kitadaniensis. Abbreviations: AD1, number of anterior denticles
er 5 mm; AD2,
width of posterior denticle as seen in labial or lingual view; BW, labial-lingual basal width of tooth; CH, crown height
FABL, fore-aft base length; d, dentary; mx, maxillary; pm, premaxillary; PD1, number of posterior denticles per 5 mm;
PD2, basal width of posterior denticle as seen in labial or lingual view; Pos, tooth position; TH, total height of crown
and root of tooth.
96080810 mx 50 xx 18.0 12.5 0.40 12.5 0.40 7.5
96081134 ? xx xx xx xx xx 12.5 0.40 xx
97080208 mx xx xx 9.5 20.0 0.25 20.0 0.25 xx
33.4 xx 17.4 16.5 0.30 16.5 0.30 7.5
97082330 mx 17 41.4 9.0 17.0 0.29 17.0 0.29 5.1
97082367 mx 23++ xx 14+ 17.0 0.29 14.0 0.36 6.5+
97082574 mx 33 xx 11.9 17.5 0.29 17.5 0.29 5.7
97082728 mx 41+ xx 15.6 15.0 0.33 12.5 0.40 7.4
9712201 mx 37+ Xx 14 19.0 0.26 16.1 0.31 5.5
9712203 mx 31.3 xx 15.4 14.0 0.36 14.0 0.36 6.1
34 xx 13.2 15.0 0.33 15.0 0.33 8.2
17+ 31+ 8.2 15.0 0.33 16.5 0.30 6.0
9712206 mx 26 xx 14.6 20.0 0.25 16.5 0.30 xx
9712229 mx xx xx xx xx xx 17.0 0.30 xx
9712231 ?
9712232 ?
18.8 xx 11.5 19.0 0.26 16.0 0.30 5.6
9712234 mx 12.6 xx 10.4 16.5 0.30 16.5 0.30 4.6
9712235 mx 25 xx 13.0 17.0 0.29 14.0 0.36 xx
18.5 xx 12.0 19.0 0.26 16.0 0.31 5.0
9712237 ?
9712238 ?
9712239 ? 18+ xx 7.4 20.0 0.25 20.0 0.25 4.9
18 xx 9.9 19.5 0.26 18.0 0.28 4.2
xx xx 16.5 15.0 0.33 xx xx 7.8
980801101 ? xx xx xx 15.0 0.33 xx xx xx
xx xx 8.0 20.0 0.25 19.0 0.26 5.5
980803120 mx 24+ xx 12.0 20.0 0.25 18.0 0.28 5.3
980803123 ? xx xx xx 17.0 0.29 15.0 0.33 xx
980804135 mx 17.6+ xx 8+ 17.5 0.29 16.0 0.32 4.9
980804144 ? xx xx xx xx xx 11.0 0.45 xx
980805101 mx 33+ xx xx 19.0 0.26 16.0 0.31 3.5+
980806009 ? 27+ xx xx 14.0 0.36 14.0 0.36 xx
980810141 mx 34 xx 15.9 14.0 0.36 13.0 0.38 5.6
980813008 mx 23 xx 10.5 16.0 0.31 16.0 0.31 5.6
27.5+ xx 12.0 16.0 0.31 15.0 0.33 9.5
25+ xx 13.4 17.5 0.29 17.5 0.29 6.5
98081540 mx 54.8 xx 22.0 14.0 0.36 12.5 0.40 7.5
980819055 mx 32+ xx 13.5 16.5 0.30 15.0 0.33 5.4
980819173 ? xx xx xx 15.0 0.33 xx xx xx
39+ xx 17.9 xx xx 15.0 0.33 9.4
6 xx 5.0 25.0 0.20 22.0 0.23 2.3
CARNOSAURIA von Huene, 1920
Fukuiraptor kitadaniensis Azuma and Currie, 2000
Specimens used in this study (Teeth are listed in Table 1)
FPDM-V97122 (holotype), associated skeleton (includes humeri and right femur)
FPDM-V97122BNA3, femur, right, individual 3 (size class 2)
FPDM-V97122BNA12, femur, right, individual 5 (size class 3)
Currie and Azuma - New Fukuiraptor with a growth series
FPDM-V970730003, femur, proximal two thirds of right,
FPDM-V97080623, femur, left (probably an ornithopod so do not include in measurements or on final of
this list)
FPDM-V97080937, femur, left (size class 1)
FPDM-V97081115, humerus, right
FPDM-V97081201, femur, right, individual 4 (size class 2)
FPDM-V97081317, tibia, right
FPDM-V97081330, femur, right, individual 1 (size class 1)
FPDM-V970813046, femur, right,
FPDM-V970814001, tibia, right
FPDM-V970820060, tibia, right
FPDM-V970821039, femur, right,
FPDM-V97082120, humerus, right
FPDM-V97082553, humerus, left
FPDM-V98072302, femur, left (size class 1)
FPDM-V980723005, humerus, right
FPDM-V980801141, manual ungual with proximodorsal lip
FPDM-V980805018, femur, right
FPDM-V9708102884, femur, right (shaft only)
FPDM-V980813017, femur, right, individual 2 (size class 1)
FPDM-V980815162, elongate, relatively straight manual ungual.
FPDM-V98082026, pedal phalanx III-2
FPDM-V990410001, manual phalanx I-1
FPDM-V99090901, femur, distal end of left,
FPDM-V9912141, tip of small manual ungual
FPDM-V97120001, femur, proximal head of left
FPDM-V98120001, femur, shaft only of left
FPDM-V98120002, femur, shaft only of left
FPDM-V9812638, femur, shaft only of right
Locality and Ag e
The Kitadani locality is on the Sugiyama River in the northern part of the city of Katsuyama, Fukui
Prefecture (Latitude 36o7'N, Longitude 136o33'E). Lower Cretaceous (Barremian) Kitadani Formation
(Akaiwa Subgroup, Tetori Group).
Institutional abbreviations
FPDM-V, Fukui Prefectural Dinosaur Museum, vertebrate collection, Katsuyama, Fukui.
Five teeth were associated with the holotype skeleton of Fukuiraptor kitadaniensis (Azuma and
Currie, 2000), including one in the socket of a dentary fragment. In addition to these, there is a tooth in
one of the sockets of a posterior fragment from a left maxilla (FPDM-V9712201) of the holotype. The
posterior left maxillary fragment figured by Azuma and Currie (2000, Figs. 3A-C) was incorrectly la-
beled as this specimen, but is actually that of a referred specimen (FPDM-V9712229).
J. Paleont. Soc. Korea. Vol. 22, No. 1, 2006
. 1. Fukukiraptor kitadaniensis, left
remaxillary tooth of the holotype in
osterior (A, B), labial (C) and distal (D)
views. The plaster fills an impression in the rock of the missing part of the tooth, and includes a cast of the anterior carina.
midline of anterior surface
anterior carina
osterior carina.
Two premaxillary teeth are known for Fukuiraptor (Table 1), the best (Fig. 1) of which belongs to the
holotype. The distal tip of the tooth is missing, partly because of wear and partly because of minor
damage. The posterior carina forms the posterolateral edge of the tooth, and extends from below
gum-line at the beginning of the enameled crown to the broken tip of the tooth. The anterior carina is
posterolingual to the anterior longitudinal midline of the tooth, which gives the crown a J-shaped cross
section (Fig. 1D). The carina extends distally from the enamel-dentine contact at the base of the crown
(below gum-line) to the broken tip of the tooth. The first denticle is about 1.5 mm distal to the proximal
end of the anterior carina, and was probably just above gum-line. The anterior denticles are low and
rounded, but their basal diameters are the same or slightly more than those of posterior denticles at equiv-
alent heights in the tooth. The posterior denticles are about twice the height of the anterior denticles, even
though they have equivalent basal diameters, and are distally hooked (Fig. 1B). The root is incomplete,
but there was clearly no constriction between root and crown.
A maxillary crown from the holotype (Fig. 2A, and fig. 4 in Azuma and Currie, 2000) shows that
Fukuiraptor had narrow, blade-like cheek teeth. This crown is 31.3 mm high, and based on size compar-
isons with other teeth in the type, it is probably one of the last maxillary teeth. The denticulate anterior
Currie and Azuma - New Fukuiraptor with a growth series
. 2. Maxillary (A, B) and dentary (C, D) teeth of Fukuiraptor kitadaniensis. A, right maxillary tooth of holotype
(FPDM-V9712203) in anterior and lingual views; B, left maxillary tooth (FPDM-V98081540) in labial and anterior
aspects; C, left dentary tooth (FPDM-V98120001) in anterior and labial views; D, third right dentary tooth of holotype
(FPDM-V9712204) displayed in anterior and lingual aspects.
carina extends from just above gum-line to the tip of the tooth, whereas the denticulate posterior carina
starts just below gum-line at the enamel-dentine interface. Denticles are small near the tip, but went right
across the top of the pointed end. Anterior denticles are subequal with posterior denticles in terms of bas-
J. Paleont. Soc. Korea. Vol. 22, No. 1, 2006
. 3. Bivariate scatter
lots comparing aspects of tooth dimensions with those of various theropods. A, FABL versus
BW of tooth crowns in Fukuiraptor (triangles), dromaeosaurids (X), carcharodontosaurids (squares) and tyrannosaurids
(diamonds). B,logarithms of FABL versus basal diameters of posterior serrations in Fukuiraptor (triangles), carchar-
odontosaurids (squares) and tyrannosaurids (diamonds).
al width, but are only about two-thirds the height. The posterior denticles are hooked towards the tip of
the tooth. Oblique blood grooves trail away from between the bases of almost all denticles (fig. 4 of
Azuma and Currie, 2000) on both labial and lingual sides.
The maxillary fragment from the holotype (FPDM-V9712201), which is coincidentally from the same
position in the left maxilla of the other, slightly smaller individual (FPDM-V9712229), has been pre-
pared to expose a germ tooth in the socket. Most of the crown (which is the second last maxillary tooth)
is preserved, and shows that the teeth of Fukuiraptor were anteroposteriorly long but labial-lingually
narrow. The crown lacks only the tip and is slightly more than 37 mm tall, with a basal cross-section of
14 x 5.5 mm. Most of the anterior carina is covered by bone so it is difficult to see how far it extends
down the tooth, but like the posterior carina, it is denticulate. Although the basal diameter of each ante-
Currie and Azuma - New Fukuiraptor with a growth series
. 4. Anterior maxillary tooth (FPDM-V97082728) of Fukuiraptorin anterior (A), lingual (B), labial (C) and
rior serration is subequal to an equivalent posterior denticle, the anterior denticles are much shorter than
the posterior ones. In this tooth, the maximum basal diameter of a serration (as seen in lingual aspect) is
0.31 mm, which works out to be about 16 denticles per 5 mm (=5 mm/0.31; a standard metric for thero-
pod tooth comparison). There are problems with this measurement, however, because the carina in small-
er theropods may be less than 5 mm long, and because denticle sizes are smaller at the proximal and dis-
tal ends of a carina. The minimum number of denticles per millimeter would be a better standard for
comparison between theropods, although we recommend that the most useful measurement is probably
the average basal diameter of the largest denticles.
In the referred maxilla (FPDM-V9712229), there is a fragment of a germ tooth in the third last alveo-
lus, and it preserves a 13 millimeter section of the posterior carina. The maximum basal diameter for a
posterior denticle as seen in lingual view is 0.30. The third last alveolus is incomplete, but the second last
one is 15 x 7 mm, confirming that the basal cross-section of a posterior maxillary tooth of Fukuiraptor
was longer than wide. The last alveolus is smaller but has similar proportions (11.8 x 5.9).
Using the characteristics found in maxillary teeth of the holotype of Fukuiraptor kitadaniensis, iso-
lated maxillary teeth (Fig. 4) of other individuals can be identified. These characteristics include rela-
tively narrow, blade-like crowns in which the Fore-Aft Basal Length (FABL) is double the measurement
of the basal width perpendicular to the level where FABL is measured. The carinae are positioned along
the anterior and posterior vertical margins of the teeth, and the anterior carina is not significantly offset
lingually. Unlike coelurosaur teeth, the longitudinal axis of the tooth is sinuous when viewed anteriorly
(Fig. 4A) or posteriorly (Fig. 4D). The denticles are relatively small (Table 1, more than 12.5 denticles
per 5 mm), but like most coelurosaurian teeth, the posterior denticles are distally hooked. Although not
present on all teeth, blood grooves are another way to separate Fukuiraptor teeth from those of other
theropods in the Kitadani quarry.
J. Paleont. Soc. Korea. Vol. 22, No. 1, 2006
The crown of one dentary tooth was recovered with the holotype, and it appears to be the third tooth
from the right side (Fig. 2D). The crown is 34 mm high, and like anterior dentary teeth in most theropods,
the base of the crown is relatively short (Table 1) anteroposteriorly compared to the basal width
(BW/FABL ratio is 0.62). The proximodistal basal widths of anterior denticles are the same as those of
equivalent posterior denticles. Although all of the anterior denticles are heavily worn, they were labiolin-
gually narrower and appear to have been much shorter than the posterior denticles. The serrations of the
dentary tooth are the same size as the anterior premaxillary denticles of the holotype, larger than the pos-
terior premaxillary ones, similar to most of the maxillary ones, but larger than those from teeth of the
posterior part of the maxilla (Table 1). The denticulate anterior carina only extends along the distal half
of the anterior surface of the tooth, whereas the denticulate posterior carina forms the entire posterior
margin of the tooth. Another tooth in the alveolus of a dentary fragment from the holotype was described
briefly by Azuma and Currie (2000).
Teeth of Fukuiraptor are similar to those of many other carnosaurs. The cheek teeth are compressed la-
bial-lingually, even more than the blade-like teeth of carcharodontosaurids (Fig. 3A, chart showing
FABL vs BW). Serrations are smaller in comparison with FABL (Fig. 3B, chart showing FABLvs basal
length of posterior denticle on a logarithmic scale) than in carcharodontosaurids and tyrannosaurids.
Posterior denticles are relatively elongate with distally hooked tips. An anterior denticle has a com-
parable basal width, but is less than half the length of a posterior serration on the same tooth. Similar to
tyrannosaurids, many Fukuiraptor cheek teeth have oblique blood grooves associated with the bases of
the serrations (Azuma and Currie, 2000). The grooves tend to be found on both labial and lingual surfa-
ces of the tooth, and are best-developed in association with the anterior denticles at the point of strongest
curvature of the anterior edge of the tooth, and with the posterior denticles. Like carcharodontosaurid
teeth (Sereno et al., 1996, Chure et al., 1999, Novas et al., 1999), the enamel on the labial and lingual
surfaces of the teeth can have broad arcuate wrinkles that sweep down towards the root and away from
the denticles. In some teeth, the anterior and posterior wrinkles extend right across the labial and/or lin-
gual surfaces of the tooth to connect with each other (as in Carcharodontosaurus and Giganotosaurus).
In anterior or posterior view, each cheek tooth has a flattened S-shaped curvature such as is also seen in
carcharodontosaurids like Giganotosaurus. At the base of the crown, the tooth initially curves labially to-
wards the outside of the jaw. This curve flattens, changes direction, and towards the tip of the tooth turns
lingually. The anterior and posterior carinae of a cheek tooth are positioned on the midline, and follow
the curvature of the tooth.
With the exception of five teeth (FPDM-V9812638, 96072901, 97082906, 980815181, 98092604) all of
the teeth from the Kitadani Formation can be referred to Fukuiraptor (Table 1). There are 42 Fukuiraptor
teeth, two of which are premaxillary, 19 are maxillary, 11 are dentary, and ten are too incomplete to
determine. The ratio of labial-lingual basal width to FABL is 0.71 for the premaxillary teeth, 0.43 for the
maxillary teeth, 0.64 for anterior dentary, and 0.46 for middle and posterior dentary teeth. This compares
well with alveolar dimensions in preserved fragments of the maxilla (0.48) and dentary (0.69 for the an-
terior fragment, 0.43 for the posterior) in the holotype of Fukuiraptor kitadaniensis.
Many of the teeth are maxillary, and show the same characteristics as the maxillary teeth of the
holotype. FPDM-V98081514 (Fig. 2B) is a large tooth that presumably occupied one of the third to fifth
maxillary tooth positions. Like other maxillary teeth of Fukuiraptor, the denticulate anterior and posteri-
or carinae extend from the gum-line to meet at the tip of the tooth. In addition to the presence of oblique
blood-grooves, there are shallow arcuate wrinkles that span the labial and lingual surfacesof the tooth as
in the holotype tooth FPDM-V9712206 (fig. 4 in Azuma and Currie, 2000), and in carcharodontosaurids
and some tyrannosauroids. These wrinkles are deeper and better defined close to the oblique blood
grooves that emerge from between the bases of adjacent denticles (both anterior and posterior). The
Currie and Azuma - New Fukuiraptor with a growth series
wrinkles are much broader and less numerous than the blood grooves, but may have a served similar pur-
pose in minimizing suction when the tooth was pulled out of flesh.
FPDM-V9712239 is a relatively small left, anterior dentary tooth with a BW/FABL ratio of 0.66. This
is the same ratio as the width versus anteroposterior length of the first alveolus of the anterior dentary
fragment (FPDM-V9712202) of the holotype. The anterior carina is lingual to the anterior longitudinal
midline of the tooth. These two facts suggest the tooth may represent the first tooth of a left dentary.
A left dentary tooth FPDM-V9812001 (Fig. 2C) is similar to the anterior dentary tooth of the holotype
(Fig. 2D) in most respects and can be assigned to Fukuiraptor. It is at least 15% larger than the holotype
tooth, and supports the idea that the described skeleton (Azuma and Currie, 2000) was not full grown
when it died. The posterior carina extends from the base of the crown to the tip, but the anterior carina is
restricted to the distal third of the front surface of the tooth. It is not clear whether this represents in-
dividual variation, variation between dentary teeth in different positions along the tooth row, or ontoge-
netic variation. Looking at what happens in other taxa suggests that the latter may be the correct
interpretation. As the teeth became larger in growing animals, the point of strongest anterior curvature
(as seen in lingual or lateral views) seems to migrate more distally in theropods. In most cases, the den-
ticulate anterior carina seems to extend from this inflection to the tip of the tooth, so it makes sense that
as the strongly curved portion of the tooth gets pushed relatively farther from the base, the relative length
of the denticulate anterior carina will also decrease.
A small (6 mm) tooth crown recovered from the Kitadani Quarry (Fig. 5) seems to be a posterior cheek
tooth of Fukuiraptor. The proportions are similar to juvenile tyrannosaurid teeth from North America
(Currie et al., 1990) and the broad, “plump” appearance would not be expected in the cheek tooth of a
small theropod species. Denticulation and faint crenulate wrinkles in the enamel are also consistent with
this identification. Because the anterior carina is limited to the distal half of the tooth, it is probably from
the dentary.
The holotype of Fukuiraptor included both humeri (Azuma and Currie, 2000). Four additional thero-
pod humeri have been recovered from the Kitadani Quarry, all of which are smaller than the holotype hu-
meri (Table 2, Fig. 6). Three are from the right side of the body, and one from the left. The deltopectoral
crest of FPDM-V97082553 is less prominent than that of the holotype (Fig. 7), but is morphologically
similar enough to tentatively identify this specimen as Fukuiraptor. The distal end of the crest is squared
off in lateral aspect, and is oriented anteroventrally. In lateral aspect, the distal margin of the deltopec-
toral crest is thickened where it borders a shallow proximal depression on the lateral surface.
FPDM-V9808115 (Fig. 8) is the largest, most complete humerus other than the holotype. It is an elon-
gate bone with a low deltopectoral crest that is intermediate in relative size between those of the holotype
and FPDM-V97082553. It is evident from growth series of other theropods (Raath 1990) that crest height
increases with positive allometry, so can only be used with caution for comparing humeri from in-
dividuals of different sizes. More significantly, FPDM-V98081115 has a more triangular deltopectoral
crest than either the holotype or FPDM-V97082553, and in lateral view the ridge between the head of the
humerus and the peak of the deltopectoral crest is straight rather than indented. The peak of the deltopec-
toral crest is 40% of the distance from the proximal to the distal end in the holotype of Fukuiraptor,
whereas it is only 25% of the distance in FPDM-V9808115. These differences strongly suggest that
FPDM-V98081115 represents a different taxon than Fukuiraptor kitadaniensis.
The remaining humeri (FPDM-V97082120, 980723005) are from small individuals (approximately
1.6 m long). The distal ends are similar to the holotype, to FPDM-V98081115, and to many other
theropods. At this time they cannot be assigned with confidence to any theropod taxon.
J. Paleont. Soc. Korea. Vol. 22, No. 1, 2006
. 5. Posterior dentary tooth (FPDM-V98120002) of a juvenile Fukuiraptor in anterior (A),
osterior (D) and side
(E, F) views. B and C are enlargements of the anterior and posterior denticles.
Currie and Azuma - New Fukuiraptor with a growth series
Table 2. Measurements of theropod humeri from the Kitadani Quarry. Abbreviations: BL, estimated body length
comparison with the femora of other theropod taxa; DW, distal width; e, estimated; eL, estimated length of humerus
Femur, length of femur estimated from humerus length; PW, width of prox imal end; SW AP, anteroposterior shaft width
SW C, minimum shaft circumference; SW T, transverse shaft width.
# Type 97081115 97082120 97082553 980723005
L 242 144 Xx Xx Xx
PW 79.8 31.1 Xx 16+ Xx
SW T 27 12.5 9.9 8.5 11.2
SW AP 31.4 11.1 9.7 8.2 9.7
SW C89 42323139
DW 64 29 20 xx 24.1
eL 245 145 105 83 115
Femur 507 284e 197e 151e 218e
BL 4.2e 2.3e 1.6e 1.2e 1.8e
. 6. Theropod humeri (medial views) from the Kitadani Quarry. A, B, holotype of Fukuiraptor kitadaniensis. C,
FPDM-V97082553 (cf. Fukuiraptor). D, FPDM-V98081115, Dromaeosauridae incertae sedis. E, FPDM-V97082120.
J. Paleont. Soc. Korea. Vol. 22, No. 1, 2006
. Isolated right theropod humerus (FPDM-V9808115) in dorsal (A), dorsolateral (B), lateral (C), ventral (D), medi
oventral (E), proximal (F) and distal (G) views.
Currie and Azuma - New Fukuiraptor with a growth series
. 8. Deltopectoral crests of right humerus (FPDM-V9808115) of unknown small theropod (A), and left humeri o
ukuiraptor kitadaniensis (B, FPDM-V97082553; C, holotype).
J. Paleont. Soc. Korea. Vol. 22, No. 1, 2006
Tab le 3 . Minimum number of individuals of Fukuiraptor
ased on the femora from the Kitadani Quarry. Abbreviations:
Body, estimated snout to tip of tail length of body; Class, size class; Ind. #, individual number; L, length; DW, distal
width; eL, estimated length of femur; PW, proximal width; SW A-P, ante roposterior shaft width; SW Cir, circumferenc
of shaft; SW T, transverse shaft width. Note that the size class is an arbitrary designation.
#right or
left LPWSW A-
DW Class Ind. # eL Body
980805018 righ
92.2 15.1 9.2 7.4 32 13.2 1 1 93 735
970813046 righ
116.3 17.4 11.7 6.6 35 17.5 2 2 116 925
970821039 righ
122.7 18 11.4 9.6 36 17 2 3 123 978
99090901 lef
xx xx xx 13.1 39 20.2 3 4 128 1021
980813017 righ
xx xx 10 12.3 40 xx 3 4 131 1046
98072302 lef
134.2 21 10 13.7 40 20.5 3 5 134 1072
9812638 righ
xx xx 13.8 11.3 41 xx 4 6 134 1070
97080937 lef
xx xx 13.4 11.4 42 21.4 4 6 137 1095
970730003 righ
xx 27.3 11.6 10.7 42 xx 4 7 137 1095
97120001 lef
xx 21.1 13.7 12.6 42 xx 4 7 137 1095
97081330 righ
134.9 20 xx xx 43 xx 4 8 135 1078
98081028 righ
xx xx 14.2 12.3 46 xx 5 9 149 1194
98120001 lef
xx xx 16.4 11.5 46 xx 5 9 149 1194
98120002 righ
xx xx 17.2 15.5 55 xx 6 10 176 1416
97122BNA3 righ
200 35 21.5 16.3 65 xx 7 12 204 1648
97081201 righ
196 35 xx xx 67 37.7 7 11 211 1707
97122BNA12 righ
244 xx 26.4 21.4 80 xx 8 13 248 2015
97122 righ
507 108.5 53 43 164 96.3 9 14 507 4200
Eighteen partial and complete theropod femora have been collected from the Kitadani Quarry (Figs. 9,
10, Table 3). Thirteen of these are from the right side of the body, and the other five are from the left. Two
of the incomplete left specimens (FPDM-97120001, 98120001) may be the same bone that became sepa-
rated during collection. Although they are in the same size range (from an animal just over a meter in
length), there is no good contact between the two pieces. No other possible connections exist between
other incomplete femora. The fact that there are thirteen right femora, ten of which are complete or al-
most complete, indicates that a minimum number of thirteen individual theropods are represented in the
collection. However, one left femur (FDM-V98072302) does not match the size of any right femur, so
the minimum number of individuals represented by femora is fourteen.
Theropod femora are rich in features and are therefore diagnostic at the family level. Many of the
Kitadani femora are incomplete, and show too few features to be identified more specifically than
Theropoda. The smallest femur (FPDM-V980805018) is 18% the length of the holotype of Fukuiraptor
kitadaniensis. However, like the femur of the holotype, it has a lateromedially elongate head (Fig. 10), an
alariform lesser trochanter separated from the shaft by a deep slot, a low moundlike process on the lateral
surface level with the base of the lesser trochanter, a distinct ridgelike fourth trochanter bounded ante-
romedially by a distinct oval muscle scar and posteriorly by a shallow depression, a gently curving shaft,
and a sharp mediodistal crest. This suite of features is characteristic of carnosaurs, and suggests that the
Currie and Azuma - New Fukuiraptor with a growth series
J. Paleont. Soc. Korea. Vol. 22, No. 1, 2006
Fig. 9. Femora of Fukuiraptor showing range in size.
A, FPDM-V97122
B, FPDM-V980805018
C, FPDM-V970813046
D, FPDM-V970821039
E, FPDM-V99090901
J, FPDM-V980813017
K, FPDM-V980723002
L, FPDM-V9812638
F, FPDM-V970730003
G, FPDM-V9712001
H, FPDM-V97081330
I, FPDM-V98081028
, FPDM-V98120001
O, FPDM-V98120002
P, FPDM-V97122BNA3
Q, FPDM-V97081201
R, FPDM-V97122BNA12
small femur is probably a juvenile Fukuiraptor. Five larger specimens (FPDM-V970813046, 970820039,
980723002, 97122BNA12, 97081201) show most of these characters, plus the presence of an accessory
wing on the lesser trochanter, a deep anterodorsal extensor groove andan adductor fossa on the distome-
dial surface of the femoral shaft. Together with the smallest specimen and the holotype, they represent a
growth series of Fukuiraptor femora. The remaining femoral specimens are not complete enough to be
certain of their affinities, although none show characters diagnostic of Dromaeosauridae or any other
coelurosaurian group.
The theropod bones from the Kitadani Quarry can be assigned with confidence to two distinct taxa.
Most of the teeth and bones can conservatively be attributed to juvenile Fukuiraptor kitadaniensis.
Although this carnosaur has been the only theropod described so far from the Kitadani Quarry, there is at
least one undescribed small theropod, possibly a dromaeosaurid from the site (Azuma and Currie, 2000).
Manual unguals collected from the same quarry suggest that there may have been as many as three differ-
ent types of small theropods in the fauna. Nevertheless, none of the preserved femora have any of the
characteristic features of coelurosaurians. It can therefore be assumed that all of the better preserved fem-
ora in this collection are from Fukuiraptor.
Teeth that can be assigned to Fukuiraptor (based on tooth and denticle morphology, and positions of
carinae) from the Kitadani Quarry show considerable variation in size. Variation in tooth size is high
within most theropod individuals. However, identification of what jaw regions each of the teeth belong to
demonstrates that the Fukuiraptor teeth came from individuals of different sizes. Some of those in-
dividuals were much smaller than the holotype specimen (Azuma and Currie 2000), and one was clearly
Fukuiraptor teeth are distinctive amongst the teeth from the Kitadani Quarry. However, they are sim-
Currie and Azuma - New Fukuiraptor with a growth series
. 10. Right femora of Fukuiraptor kitadaniensis in
view. A) FPDM-V980805018. B) FPDM-V970813046. C) FPDM-
V970730003. D
FPDM-V97081201. E
J. Paleont. Soc. Korea. Vol. 22, No. 1, 2006
ilar to theropod teeth found in many localities in Japan and around the world. Like carcharodontosaurids
from Africa and South America, they are narrow and blade-like, have relatively small serrations, and
have arcuate wrinkles in the enamel on labial and lingual surfaces. Like carcharodontids as well, the in-
terdental plates are fused to each other and to the margins of the jaws.
Chure et al. (1999) described a tooth from the late Cretaceous Mifune Group of Japan that is very sim-
ilar in most respects (tooth size and shape, serration size, curved enamel wrinkles) to an anterior maxil-
lary tooth of Fukuiraptor. They concluded that the Mifune tooth compares more closely with carchar-
odontosaurid teeth than with any other type of theropod tooth described. However, when the ratio of
FABL is compared with BW (Fig. 3A) and posterior denticle size is compared with FABL (Fig. 3B), the
Mifune tooth falls on the regressions for Fukuiraptor rather than Carcharodontosauridae.
Although Fukuiraptor teeth have oblique blood grooves similar to those of tyrannosaur teeth, neither
they nor any of the other theropod teeth recovered from the Kitadani Quarry can be identified as
tyrannosaurid. The only premaxillary teeth recovered so far have J-shaped cross-sections, like the pre-
maxillary teeth of most theropod families (Currie et al., 1990). Manabe (1999) reported the discovery of
an isolated tyrannosauroid premaxillary tooth from a nearby area in Fukui Prefecture, but from the un-
derlying Jobu Formation (Itoshiro Subgroup, Tetori Group, Lower Cretaceous). The specimen was there-
fore recovered from an older formation, and represents a more ancient animal than Fukuiraptor.
Premaxillary teeth of tyrannosauroids have also been reported from the younger Mifune Group of Japan
(Anonymous, 1998), along with the carcharodontosaurid-like cheek teeth. Recent descriptions of tyran-
nosauroids from the Late Jurassic and Early Cretaceous of Europe and Asia (Hutt et al., 2001; Xu et al.,
2004; Xu et al., 2006) confirm the likelihood of the Japanese tyrannosauroid records.
The smallest individual of Fukuiraptorin the Kitadani Quarry is less than a quarter the size of the
holotype. A fourfold increase in size is reasonable for a growth series of an animal of this size, and prob-
ably does not represent a complete growth series. For example, Nile crocodiles grow to about the same
length as Fukuiraptor, but are only 0.25 m long at birth (Cott, 1961).
It is difficult to study ontogenetic changes in limb proportions when dealing with unassociated speci-
mens from bonebeds. However, using allometric equations developed for other theropods, such as tyran-
nosaurids (Currie, 2003), the approximate body lengths of each individual can be calculated (Table 3).
These were arranged into arbitrary size classes, with the smallest individual being assigned to Class 1,
and the largest to Class 9. Fukuiraptor size classes in the bonebed are nearly evenly distributed, with
peaks of four individuals each for size classes 4 and 7. There are not enough specimens for this bimodal
distribution curve to be statistically significant, but it provides weak evidence in support of this being an
attritional death assemblage (Voorhies, 1969).
Fukuiraptor remains in the Kitadani Quarry are common in comparison with the fossils of herbivorous
dinosaurs. Bonebeds dominated by theropods are very rare anywhere in the world, and the high number
of carnivores in the Kitadani Quarry suggests that there were some unusual circumstances involved in the
genesis of the site. Perhaps it was taphonomic, or perhaps it was more directly involved with the behav-
iour of Fukuiraptor itself. The concentration of juvenile Fukuiraptor teeth and bones may indicate that
this was close to where the theropods were nesting, perhaps similar to the scenario described by Bakker
and Bir (2004). There is a mixed faunal bonebed in Utah (USA) with a similar concentration of
theropods. The Upper Jurassic Cleveland-Lloyd quarry is dominated by more than seventy individuals
of Allosaurus fragilis, and has been interpreted as a predator trap (Madsen, 1976; Miller et al., 1996;
Richmond and Morris, 1996), or as a drought-induced mass death assemblage (Gates 2005). Coelophysis
(Colbert, 1989) and Syntarsus (Raath, 1990) are two examples of theropods that died en masse in Late
Triassic to Early Jurassic times, whereas trackway sites (Ostrom, 1972) suggest that coelophysoids may
have travelled in packs. The Coelophysis bonebed has also been interpreted as species-selectivity in
Currie and Azuma - New Fukuiraptor with a growth series
drought conditions (Schwartz and Gillette, 1994). In Late Cretaceous times, bonebeds dominated by ty-
rannosaurids (Larson, 1997; Currie, 2000; Currie et al., 2004), carcharodontosaurids (Coria and Currie,
1997, 2006), dromaeosaurids (Ostrom, 1969; Maxwell and Ostrom, 1995) and troodontids (Varricchio
and Currie, 1991) have been used to suggest that these animals hunted in packs. Unfortunately, there are
no strong taphonomic signals in the Kitadani Quarry to eliminate any of these scenarios as possible ex-
planations for the high concentration of Fukuiraptor specimens.
Most of the isolated theropod teeth and bones recovered from the Kitadani Quarry are from carno-
saurs, although some of the teeth, a humerus and several unguals seem to be dromaeosaurid. One me-
dium-sized carnosaur, Fukuiraptor kitadaniensis, has been described (Azuma and Currie, 2000) from the
quarry. The type specimen had an estimated length of 4.2 m when it was alive. Azuma and Currie (2000)
suggested that it was close to adult size when it died, and that the species never became as large as the
majority of known carnosaurs. Amongst the isolated teeth and bones from the Kitadani Quarry, only one
tooth is suggestive of a slightly larger individual, and the rest of the fossils are from much smaller
individuals. Because it is more parsimonious to assume that they represent only one species of carnosaur
from the Kitadani fauna, it is likely that they represent a growth series of Fukuiraptor. At least two other
theropod taxa can be recognized in the fauna from teeth and manual unguals, but in the Kitadani Quarry
these coelurosaurs are rare animals.
The theropod teeth and bones from the Kitadani Quarry represent a minimum number of 14 in-
dividuals based on femoral counts alone. The high concentration of juvenile carnosaurs at this one site
may represent a breeding or nesting area, a predator trap, or the catastrophic demise of a social group.
Taphonomic analysis of the bones in the quarry cannot resolve which of these three options (if any of
them) is correct.
The first author would like to thank Eva Koppelhus (University of Alberta) and Yoshi Kobayashi
(Hokkaido University) for logistic support, without which it would have been impossible to do this paper.
All illustrations were done by the first author. Support for his trips to study the specimens came from
NSERC (Grant #203091-02) and the Fukui Prefectural Dinosaur Museum. The paper was improved by
careful reviews by Yoshi Kobayashi and Dale Winkler.
일본 전기 백악기 Kitadani 채석장에서 산출된 Fukuiraptor
(공룡, 수각류)개체발생을 포함한 새로운 표본들
Philip J. Currie1 and Yoichi Azuma2
1University of Alberta, Department of Biological Sciences, 11145 Saskatchewan Drive, Edmonton, Alberta
T6G 2E9, Canada
2Fukui Prefectural Dinosaur Museum, 5-11 Terao, Muroko, Katsuyama, Fukui 911-8601, Japan
J. Paleont. Soc. Korea. Vol. 22, No. 1, 2006
요 약: 모식표본 Fukuiraptor kitadaniensis 와 같은 종에 속하는 뼈와 이빨들이 일본 후쿠이현 전기 백악기(Albian)
지층인 Kitadani 화석지에서 발굴되었다. 이들 화석들은 계통발생학적 위치를 결정하는데 도움이 되는 여러 정보를
가지고 있을 뿐 아니라 일련의 개체발생을 나타내고 있. 모식표본은 미성숙 표본이며 전체 길이는 4.2 m 였다. 같은
화석지에서 산출된 다른 화석들은 이 보다 더 작은 개체의 것이다. 새끼뼈의 일부는 모식표본의 것에 1/3 보다 작다.
주요어: Fukuiraptor, 성장단계, Kitadani, 일본
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... Porfiri et al., 2014;Aranciaga Rolando et al., 2019) were added to the data set based on published photographs. Namely, three measurements (CBL, CH, AL) were taken from the photographs of F. kitadaniensis and A. wintonensis published in Currie and Azuma (2006, fig. 2) and White et al. (2015, figs. ...
... Lateral teeth of Fukuiraptor kitadaniensis found from the Kitadani Formation in the Tetori Group are narrow and blade-like and have mesial and distal denticles of subequal sizes (Azuma and Currie, 2000;Currie and Azuma, 2006). Although such denticle morphology is also present in OMFJ V-1, F. kitadaniensis is different from OMFJ V-1 in possessing the following characteristics as described in previous studies (Azuma and Currie, 2000;Currie and Azuma, 2006): the mesial carina and its serrations extending to the level of the cervix or slightly distal to it; a highly labiolingually compressed crown; the crosssection at the cervix narrow and mesiodistally-pointed, lenticular-shaped; asymmetric or apically hooked denticles and well-developed interdenticular sulci. ...
... Lateral teeth of Fukuiraptor kitadaniensis found from the Kitadani Formation in the Tetori Group are narrow and blade-like and have mesial and distal denticles of subequal sizes (Azuma and Currie, 2000;Currie and Azuma, 2006). Although such denticle morphology is also present in OMFJ V-1, F. kitadaniensis is different from OMFJ V-1 in possessing the following characteristics as described in previous studies (Azuma and Currie, 2000;Currie and Azuma, 2006): the mesial carina and its serrations extending to the level of the cervix or slightly distal to it; a highly labiolingually compressed crown; the crosssection at the cervix narrow and mesiodistally-pointed, lenticular-shaped; asymmetric or apically hooked denticles and well-developed interdenticular sulci. However, isolated teeth referred to F. kitadaniensis show that these characteristics apparently vary in the specimens, with some specimens having a relatively thick crown, a lanceolate basal cross-section and the mesial carina terminating approximately at the half height of the crown (H.U. ...
An isolated theropod tooth was found in the HauterivianBarremian Itsuki Formation of the Tetori Group in the Kuzuryu district, Ono City, Fukui Prefecture, central Japan. The present specimen, OMFJ V-1, shows a thick lanceolate basal cross-section and small mesial and distal denticles. A cladistic analysis based on the dental characters suggested that OMFJ V-1 be classified as belonging to Allosauroidea or Tyrannosauroidea. Principal component and linear discriminant analyses also suggested that OMFJ V-1 belongs to either of these two theropod clades. The posterior probabilities obtained in the linear discriminant analyses indicated that the confidence of the classification as Allosauroidea is slightly higher than that for Tyrannosauridae. However, because these analyses also supported possibilities of OMFJ V-1 belonging to other theropod clades to lesser extents, its taxonomic referral remains ambiguous. If OMFJ V-1 belongs to Tyrannosauroidea, it would indicate that a medium-sized tyrannosauroid already appeared in central Japan during the HauterivianBarremian age. On the other hand, if OMFJ V-1 belongs to Allosauroidea, it would indicate that at least two medium-to-large-sized theropods, allosaurids and tyrannosaurids, lived almost coevally in this region. The third possibility is that OMFJ V-1 belongs to Megaraptora. If such affinities are established, it would represent the oldest record of this clade of theropods.
... Aranciaga Rolando et al. (2022: Supplementary Information B) also suggested that four teeth from the upper Strzelecki Group belonged to non-megaraptorid megaraptorans (NMV P186353, NMV P210084, NMV P212859 and NMV P230871). The mesial carinae of these teeth reportedly bear denticles all the way to the base of the crown, as in Fukuiraptor (Azuma and Currie 2000;Currie and Azuma 2006), but in contrast to Australovenator, in which the mesial denticles are restricted to the apex of the crown (Hocknull et al., 2009;White et al., 2015b). The inclusion of the isolated tooth NMV P186353 by Aranciaga Rolando et al. (2022: Supplementary Information B) in a sample derived from the upper Strzelecki Group perpetuates an error made by Benson et al. (2012) and corrected by Poropat et al. (2018): this specimen is in fact from the lower Albian portion of the Eumeralla Formation at Dinosaur Cove. ...
... Although we agree that at least one tooth from Flat Rocks (NMV P212859: Benson et al., 2012) hosts denticles on the mesial surface, we note that most sufficiently complete exemplars present either no denticles or denticles restricted to a very small region of the mesial carina Kotevski and Poropat, 2022). This is in contrast to the condition in Fukuiraptor, where denticles persist along most of the mesial carina (Azuma and Currie, 2000;Currie and Azuma, 2006). Non-or incompletely-denticulate mesial carinae are observed in several megaraptorids, including Megaraptor (Porfiri et al., 2014), Murusraptor (Coria and Currie, 2016) and Orkoraptor . ...
Cretaceous (non-avian) theropod dinosaurs from Australia are poorly understood, primarily because almost all specimens described thus far comprise isolated postcranial elements. In Australia, only three non-dental cranial elements pertaining to Theropoda have been reported: the left and right dentaries of Australovenator wintonensis from the Winton Formation (Cenomanian–lowermost Turonian) of Queensland, and an isolated surangular from the Eumeralla Formation (lower Albian) of Victoria. Herein, we report the first evidence of non-mandibular cranial material of a non-avian theropod from Australia: a left frontal and fused parietal fragment from the Lower Cretaceous (lower Aptian) upper Strzelecki Group of Victoria. The specimen shares several synapomorphies with the frontals assigned to Megaraptoridae, including an anteroposteriorly elongate postorbital articulation and a truncated nasal articular surface. Accordingly, we regard this frontal as Megaraptoridae gen. et sp. indet. We performed both parsimony-based and Bayesian-based phylogenetic analyses to support our assignment, and both analyses support a placement within Megaraptoridae. However, this specimen appears to possess plesiomorphic characters relative to other megaraptorid frontals, lacking dorsoventrally high walls of bone that emarginate the nasal and prefrontal articular surfaces. The plesiomorphies of this specimen have implications for the evolution of the megaraptoran skull roof, suggesting the acquisition of specialised adaptations for longirostry over time. This specimen improves the limited record of Cretaceous Australian theropod cranial remains, and provides limited support for the hypothesis that Megaraptoridae might have originated in Australia.
... Similarly, the specimens described in the present study cannot be assigned to the juvenile of Fukuiraptor from the same stratigraphic layer because each of them presents a suite of characters present in ornithomimosaurs but absent in Fukuiraptor. For example, in Tyrannomimus, the dorsal centrum does not bear a deep lateral depression, the deltopectoral crest is not extended as a conical process, the manual ungual is not laterally compressed nor strongly recurved, the pubic peduncle of the ilium is not mediolaterally broad, the femur has a distinct trochanteric shelf, the fibular condyle of the tibia is relatively small and not clearly separated from the rest of the proximal end, and the metatarsals have broader and distinct articular surfaces to each other, unlike those of Fukuiraptor 57,58 . ...
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Ornithomimosauria consists of the ostrich-mimic dinosaurs, most of which showing cursorial adaptations, that often exhibit features indicative of herbivory. Recent discoveries have greatly improved our knowledge of their evolutionary history, including the divergence into Ornithomimidae and Deinocheiridae in the Early Cretaceous, but the early part of their history remains obscured because their fossil remains are scarce in the Aptian–Albian sediments. In recent years, many isolated ornithomimosaur remains have been recovered from the Aptian Kitadani Formation of Fukui, central Japan. These remains represent multiple individuals that share some morphological features common to them but unknown in other ornithomimosaurs, suggesting a monospecific accumulation of a new taxon. As a result of the description and phylogenetic analysis, the Kitadani ornithomimosaur is recovered as a new genus and species Tyrannomimus fukuiensis, the earliest definitive deinocheirid that complements our knowledge to understand the early evolutionary history of Ornithomimosauria. Due to its osteological similarity to Tyrannomimus, a taxon previously considered an early tyrannosauroid based on fragmentary specimens, namely Aviatyrannis jurassica, may represent the earliest ornithomimosaur from the Upper Jurassic of Europe, significantly expanding the temporal and biogeographic range of Ornithomimosauria. This finding fills a 20-million-year ghost lineage of Ornithomimosauria implied by the presence of the oldest fossil record of Maniraptora from the Middle Jurassic and is consistent with the hypothesis that their biogeographic range was widespread before the Pangaean breakup in the Kimmeridgian.
... Using the dataset only based on the tooth-crown characters, other two features were recovered as synapomorphies: 4) lateral teeth with a depression in the labial surface, centrally positioned on the crown, and restricted to the crown base or extended along the basal half of the crown, a condition present in Australovenator (White et al., 2015a) and probably in Fukuiraptor (see Azuma and Currie, 2000;Currie and Azuma, 2006); and 5) broad interdenticular space at mid-crown of the lateral teeth. An interdenticular space more than one-third of the denticle width is present in Australovenator (White et al., 2015a;Hendrickx et al., 2019) and Neovenator (see Hendrickx et al., 2019). ...
The abundant record of theropods from Bajo de La Carpa Formation (Neuquén Group, Santonian), known from the end of the nineteenth century, come from numerous locations within the Neuquén Basin. During the excavation of the titanosaur Bonitasaura salgadoi at the La Bonita fossiliferous site, northwest of Río Negro province Argentina, were recovered three isolated teeth assignable to non-avian theropod dinosaurs. Previous studies of these dental materials suggested that MPCA-Pv-247 corresponds to an indeterminate tetanure possibly related to Orkoraptor, a taxon of uncertain phylogenetic position at that moment, and MPCA-Pv-249 and 251 as possible abelisauroids. Three methods were carried out, namely, a cladistic analysis performed on a dentition-based data matrix, and a discriminant and cluster analyses performed in a large dataset including measurements of non-avian theropod teeth. The results assign for the first time a confidently phylogenetic position to the described dental material. The analysis shows that MPCA-Pv 247 belongs to Megaraptoridae, whereas MPCA-Pv 249 and 251 were recovered as belonging to Abelisauridae, supporting in a reliable way the previous assignments. The results show the presence of Megaraptoridae at La Bonita and, additionally, they represent an evidence of the first direct association of megaraptorids and abelisaurids at the same locality of the Bajo de La Carpa Formation, according to similar associations from other units of the Neuquén Group.
... Our analysis supports this and also, based on our phylogenetic results, we observe a correlation between the morphology, size and age in the megaraptoran records ( Fig. 18A-C). Smaller (4-4.5 m), early-branching megaraptoran species evolved during the Barremian-Aptian of Asia, South America and Australia 4,5,11,22,24 . Medium-sized (4.5-6 m) megaraptorids appeared during Aptian through lower Turonian times in Australia and South America 20,24,26,28,29,32 . ...
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Megaraptora is a theropod clade known from former Gondwana landmasses and Asia. Most members of the clade are known from the Early to Late Cretaceous (Barremian–Santonian), with Maastrichtian megaraptorans known only from isolated and poorly informative remains. The aim of the present contribution is to describe a partial skeleton of a megaraptorid from Maastrichtian beds in Santa Cruz Province, Argentina. This new specimen is the most informative megaraptoran known from Maastrichtian age, and is herein described as a new taxon. Phylogenetic analysis nested the new taxon together with other South American megaraptorans in a monophyletic clade, whereas Australian and Asian members constitute successive stem groups. South American forms differ from more basal megaraptorans in several anatomical features and in being much larger and more robustly built.
... Comparisons: These isolated specimens, found in multiple localities, are all identifiable as carcharodontosaurs based on numerous apomorphies. The teeth possess many characters found in the Carcharodontosauria, including transverse enamel undulations, basally inclined interdenticular sulci, and S-shaped mesiodistal profile (Benson, Carrano & Brusatte, 2010;Coria & Currie, 2006;Currie & Azuma, 2006;Currie & Carpenter, 2000;Harris, 1998;Naish, 2011;Novas et al., 2013;Sereno et al., 1996). While tall and moderately recurved, this tooth morphotype lacks the extensive anterior carina, extreme labiolingual compression, and large size observed in carcharodontosaurids such as Mapusaurus, Giganotosaurus, and Carcharodontosaurus (Coria & Currie, 2006;Novas et al., 2013). ...
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While the terrestrial fossil record of the mid-Cretaceous interval (Aptian to Cenomanian) in North America has been poorly studied, the recent focus on fossil localities from the western United States has offered a more detailed picture of vertebrate diversity, ecosystem dynamics and faunal turnover that took place on the western landmass of Laramidia. This is in stark contrast to the terrestrial record from the eastern landmass of Appalachia, where vertebrate fossils are rare and consist mostly of isolated and fragmentary remains. However, a detailed understanding of these fossil communities during this interval is necessary for comparison of the faunal patterns that developed during the opening of the Western Interior Seaway (WIS). The Woodbine Group of Texas is a Cenomanian age (95–100 mya) deposit consisting of shallow marine, deltaic, and terrestrial communities, which were only recently separated from their western counterparts. These deposits have yielded a wealth of vertebrate remains, yet non-avian theropods are still largely unknown. Recently, multiple localities in the Lewisville Formation of the Woodbine Group have yielded new non-avian theropod material, including numerous isolated teeth and postcranial remains. While largely fragmentary, this material is sufficiently diagnostic to identify the following taxa: a large-bodied carcharodontosaur, a mid-sized tyrannosauroid, a large ornithomimosaur, a large dromaeosaurine, a small dromaeosaurid, a small troodontid, and a small coelurosaur. Some of these groups represent the first occurrence for Appalachia and provide a broader understanding of a newly expanded faunal diversity for the Eastern landmass. The Lewisville Formation theropod fauna is similar in taxonomic composition to contemporaneous deposits in Laramidia, confirming that these groups were widespread across the continent prior to extension of the WIS. The Lewisville Formation documents the transitional nature of Cenomanian coastal ecosystems in Texas while providing additional details on the evolution of Appalachian communities shortly after WIS extension.
... This specimen represents one of the most complete sacra for the group and the oldest record in South America. The Japanese Fukuiraptor was found in Albian sediments (Kitadani Formation) and is represented by more than thirty specimens, most of them isolated limb bones (Azuma and Currie 2000;Currie and Azuma 2006). Australovenator was found in Cenomanian-Turonian outcrops of Australia and is represented by an almost complete specimen (Hocknull et al. 2009;White et al. 2012White et al. , 2013aWhite et al. , 2013bWhite et al. , 2015 from the Winton Formation. ...
Aerosteon riocoloradensis represents one of the most complete megaraptorans yet discovered. This theropod comes from Anacleto Formation (Campanian) of Mendoza Province, Argentina. The aims of this contribution are: to present a detailed, bone by bone description of this specimen with figures of each bone; provide comparisons to other closely related theropods; revise the original assignation and diagnosis of such taxa. Three bones were re-assigned and almost all the autapomorphies of Aerosteon were modified. Features in the vertebral columns, which are shared with other megaraptorans, show that these theropods shared features with basal coelurosaurs. Anatomical Abbreviations ACDL: Anterior centrodiapophyseal lamina; CDF: Centrodiapophyseal fossa; CPAL: Centroparapophyseal lamina; CPRL: Centroprezygapophyseal lamina; CPRF: Centroprezygapophyseal fossa; CPR-CDF: Centroprezygapophyseal-centrodiapophyseal fossa; Hye: Hyposphene; Hym: Hypantrum; ILT: Intervertebral ligament tuberosity; IPOL: Infrapostzygapophysela lamina; IZL: Intrazygapophyseal lamina; PADL: Paradiapophyseal lamina; PAD-CDF: Paradiapophyseal-centrodiapophsyeal fossa; PCDL: Posterior centrodiapophyseal lamina; POEL: Postzygaepipophysela lamina; PODL: Postzygadiapophyseal lamina; POSF: Postspinal fossa; POCDF: Postzygapophsyeal-centrodiapophyseal fossa; Poz: Postzygapophysis; PRDL: Prezygadiapophyseal lamina; PRPAF: Prezygaparapophyseal fossa; PRPAL: Prezygaparapophyseal lamina; PRSF: Prespinal fossa; PRSL: Prespinal lamina; PRD-CDF: Prezygadiapophyseal-centrodiapophyseal fossa; PRD-PADF: Prezygadiapophyseal-paradiapophyseal fossa; PRD-PODF: Prezygadiapophyseal-postzygadiapophyseal fossa; PRCDF: Prezygapophyseal-centrodiapophyseal fossa; Prz: Prezygapophyses; SDF: Supradiapophsyeal fossa; SDL: Supradiapophyseal lamina; SPOF: Spinopostzygapophyseal fossa; SPOL: Spinopostzygapophyseal lamina; SPRF: Spinoprezygapophyseal fossa; SPRL: Spinoprezygapophyseal lamina; SR(number): Sacral rib; STP(number): Sacral transverse process
Dinosaurs have attracted varying degrees of scientific and public interest since their initial description in 1824. Interest has steadily increased, however, since the late 1960s when the Dinosaur Renaissance began, and when the Canadian Journal of Earth Sciences started to publish. Since then, there has been a feedback system (international in scope) promoting increased scientific activity and ever-increasing public attention. This has led to ever more dinosaur discoveries internationally; increased numbers of museums and parks displaying dinosaurs; more publications, blogs, and other media on dinosaurs; and (most importantly) increased numbers of people and institutions doing research on dinosaurs. About 30 new species of dinosaurs are now being described every year, adding to the more than 1000 species already known. Furthermore, it is now acknowledged by most biologists and palaeontologists that modern birds are the direct descendants of dinosaurs, and that they are classified as part of the Dinosauria. Recognizing that there are more than 11 000 species of living dinosaurs has given us a better understanding of many aspects of the biology of nonavian dinosaurs. Along with technological improvements, this has revealed new—and often surprising—facts about their anatomy (bones, soft tissues, and even colours), interrelationships, biomechanics, growth and variation, ecology, physiology, behaviour, and extinction. In spite of the intensity of research over the last six decades, there is no indication that the discovery of new species and new facts about their biology is slowing down. It is quite clear that there is still a lot to be learned!
Megaraptora is a group of enigmatic, carnivorous non‐avian theropod dinosaurs from the Cretaceous of Asia, Australia, and especially South America. Perhaps the most striking aspect of megaraptoran morphology is the large, robustly constructed forelimb that, in derived members of the clade, terminates in a greatly enlarged manus with hypertrophied, raptorial unguals on the medialmost two digits and a substantially smaller ungual on digit III. The unique forelimb anatomy of megaraptorans was presumably associated with distinctive functional specializations; nevertheless, its paleobiological significance has not been extensively explored. Here we draw from observations of the pectoral girdle and forelimb skeletons of Megaraptora and myological assessments of other archosaurian taxa to provide a comprehensive reconstruction of the musculature of this anatomical region in these singular theropods. Many muscle attachment sites on megaraptoran forelimb bones are remarkably well developed, which in turn suggests that the muscles themselves were functionally significant and important to the paleobiology of these theropods. Furthermore, many of these attachments became increasingly pronounced through megaraptoran evolutionary history, being substantially better developed in derived taxa such as Australovenator wintonensis and especially Megaraptor namunhuaiquii than in early branching forms such as Fukuiraptor kitadaniensis. When considered alongside previous range of motion hypotheses for Australovenator, our results indicate that megaraptorans possessed a morphologically and functionally specialized forelimb that was capable of complex movements. Notable among these were extensive extension and flexion, particularly in the highly derived manus, as well as enhanced humeral protraction, attributes that very probably aided in prey capture.
Seven isolated eggshell fragments and six eggshell impressions were collected from the Okurodani Formation (Hauterivian to Barremian) in Shokawa, Takayama City, Gifu Prefecture, Japan. To date, these specimens represent the oldest fossil eggshells in the country. Microscopic observations classified the eggshells into Testudoolithidae indet., Ramoprismatoolithus okurai oogen. et oosp. nov. and indeterminate type. For Testudoolithidae indet., the eggshell microstructure and estimated egg size suggest that they could be laid by any of the cryptodiran turtles reported by skeletal remains from the formation: Trionychoidea, Xinjiangchelyidae and Sinemydidae. Ramoprismatoolithus okurai bears prismatic microstructure and ramifying ridges on the outer surface, the combination of which is unusual for prismatoolithid eggshells. Based on morphological observations and phylogenetic analyses, Ramoprismatoolithus was ascribed to troodontid or closely related non-avian maniraptorans. The remaining specimens consist of eggshell surface impressions without original fragments, for which oospecies and taxonomic affinity are indeterminate. These findings demonstrate that eggshell fragments shed light on small-bodied taxa that are poorly represented by skeletal remains in the region. While the fossil record of small maniraptoran species from the early Early Cretaceous is relatively scarce worldwide, Ramoprismatoolithus adds to this record and extends the confirmed geographic range of this clade. urn:
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The main bone-bearing strata are abandoned channel deposits that are part of a siltstone overbank sequence. The Coleophysis remains found at the quarry are remarkably whole and well preserved, though they range in degree of articulation from complete skeletons to isolated limbs and bones. Skeletons, partial skeletons, and bones are crudely aligned and show little evidence of predator or scavenger disturbance or surface weathering. Geologic and taphonomic evidence suggests that the dinosaurs preserved in the Ghost Ranch quarry were transported to the site as carcasses by fluvial currents. -from Authors
An isolated premaxillary tooth of tyrannosaurid from the Lower Cretaceous section of the Tetori Group, Central Honshu, Japan, complements Siamotyrannus, which is based upon an incomplete postcranium for existence of tyrannosaurids in the Early Cretaceous of Asia. The occurrence of a tyrannosaurid tooth in the Japanese early Early Cretaceous further supports the possibility that tyrannosaurids originated during the Early Cretaceous in Asia and migrated to North America when the two continents were connected via a land bridge during the early Late Cretaceous. Thickening of the premaxillary teeth might have predated the increase in body size in tyrannosaurid evolution.
The Cleveland-Lloyd Dinosaur Quarry has yielded a diverse, late Jurassic fauna that has elicited international public and scientific recognition. Nevertheless, relatively few articles, especially ones that arc widely accessible, have been published concerning this quarry. The present paper is intended as a comprehensive review of all pertinent work, and it details current views of the quarry and its fauna. The accompanying quarry map is the most extensive record of its kind, representing a compilation of all mapping data for the Cleveland-Lloyd Quarry to date. A bibliography of published works pertaining to this quarry has also been included. Scientific collecting first began at the quarry in 1929, continued to 1931, and then was conducted on an intermittent basis until 1990. Four separate institutions served as the directing agency during various years. The first and major agency was the University of Utah, followed by Princeton University, the Antiquities Section of the Utah Division of State History, and then Brigham Young University. Combined efforts produced nearly 10,000 excavated and cataloged bones. Of these, approximately 80% represent Allostaurus fragilis. Type specimens of two other carnivorous taxa, Marshosaurus bicentesimus and Stokesosaurus clevelandi, also come from the Cleveland-Lloyd Dinosaur Quarry. In total it has produced eleven species of dinosaurs, one of chelonian, four of gastropods, and three of charophytes.
In recent years dinosaurs have captured the attention of the public at an unprecedented scale. At the heart of this resurgence in popular interest is an increased level of research activity, much of which is innovative in the field of palaeontology. For instance, whereas earlier palaeontological studies emphasized basic morphologic description and taxonomic classification, modern studies attempt to examine the role and nature of dinosaurs as living animals. More than ever before, we understand how these extinct species functioned, behaved, interacted with each other and the environment, and evolved. Nevertheless, these studies rely on certain basic building blocks of knowledge, including facts about dinosaur anatomy and taxonomic relationships. One of the purposes of this volume is to unravel some of the problems surrounding dinosaur systematics and to increase our understanding of dinosaurs as a biological species. Dinosaur Systematics presents a current overview of dinosaur systematics using various examples to explore what is a species in a dinosaur, what separates genders in dinosaurs, what morphological changes occur with maturation of a species, and what morphological variations occur within a species.