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156
New Hadrosaurid (Dinosauria, Ornithopoda)
Specimens from the Lower–Middle Campanian
Wahweap Formation of Southern Utah
Terry A. Gates, Zubair Jinnah, Carolyn Levitt, and Michael A. Getty
9
Hadrosaurid ornithopods from the early to middle Campan-
ian are rare in North America, but the Wahweap Formation
of southern Utah yields specimens that are increasing the
known diversity of hadrosaurids from this poorly understood
time period. A new genus and species of lambeosaurine had-
rosaurid, Adelolophus hutchisoni, is described on the basis
of an isolated maxilla. This single element is distinct from
all other known lambeosaurine hadrosaurid maxillae in the
large medial wall, raised palatine process, and other features
associated with the raised medial wall. Another locality in the
middle of the Wahweap Formation yielded two individuals
of presumably the same species, an adult and a juvenile. The
specimens show autapomorphic morphology of the caudal
vertebrae neural spines and centra, along with a unique suite
of iguanodontian characters. Given that the only diagnostic
skull elements belong to the juvenile individual, the phy-
logenetic position of this species is unclear, although the
postcranial skeleton possesses a mix of primitive and derived
traits. The site represents a swampy environment containing
autochthonous specimens; among these, long bones exhibit
slightly preferred orientations.
In contrast to the long history of Cretaceous dinosaur collect-
ing in Montana, United States, and Alberta, Canada (Currie,
), southern Utah, United States, has been intensively
prospected for dinosaurs only since . As in other North
American terrestrial formations, hadrosaurid dinosaurs are
some of the most common fossils discovered in southern
Utah, and are providing important data on biogeographic
patterns and paleoecology of Campanian dinosaurs (Gates
and Evans, ; Gates et al., ). The hadrosaurids from
the Kaiparowits Formation (late Campanian) are becoming
well known, with multiple specimens of the two known spe-
cies of the saurolophine Gryposaurus, G.notabilis? (Gates et
al., ) and G.monumentensis (Gates and Sampson, ).
The only lambeosaurine known from the formation is an
undetermined species of Parasaurolophus (Gates et al., ).
The Wahweap Formation underlies the Kaiparowits
Formation within the Grand Staircase–Escalante National
Monument of southern Utah, and it is divided into several
members (Lower, Middle, Upper, Capping Sandstone; Fig.
.) (Jinnah and Roberts, ). Deposition of this unit took
place between ~– Ma, based on a dated volcanic ash
bed, detrital zircons, and estimated sedimentation rates (Jin-
nah et al., ). Although it is slower to produce fossil mate-
rial, this formation is providing important information on the
hadrosaurid dinosaurs that lived in southern Utah during the
early and middle Campanian (Gates et al., ). One of the
most signicant taxa is a new saurolophine named Acristavus
gagslarsoni, which is currently the earliest member of a small
clade that contains this taxon and the hadrosaurids Maia-
saura peeblesorum and Brachylophosaurus canadensis (Gates
et al., ). Several other hadrosaurid specimens have been
located within the Wahweap in addition to the referred spec-
imen of Acristavus ( ). This chapter describes
specimens from two of these sites, both briey mentioned
in Gates et al. () but not described in detail or discussed
in reference to the taxonomy of Prieto-Márquez (a). An
isolated lambeosaurine maxilla is described here as the sec-
ond new hadrosaurid species from the Wahweap Formation.
A bonebed that preserves two individuals of a possible new
species is also documented. These specimens increase the
known hadrosaurid diversity in the southern region of the
Western Interior Basin during the middle Campanian.
Institutional Abbreviations , American Museum
of Natural History, New York; , Colección Paleontológica
de Coahuila (Paleontological Collection of Coahuila)
Saltillo, Coahuila, Mexico; , Museum of the Rockies,
Bozeman, Montana; , North Carolina Museum of Nat-
ural Sciences, Raleigh, North Carolina; , Raymond M.
Alf Museum of Paleontology, Claremont, California; ,
Royal Ontario Museum, Toronto, Ontario; , Children’s
Museum of Indianapolis, Indianapolis, Indiana; , Royal
Tyrrell Museum of Palaeontology, Drumheller, Alberta;
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New Hadrosaurid Specimens from the Wahweap Formation 157
9.1. Composite stratigraphic section of the Wahweap Formation. Hadro-
saurid specimens discussed in text are labeled reflecting their stratigraphic
occurrences. The locality of UCMP 152028 is unknown, but based on an
examination of the host matrix it is likely to have originated from the Upper
Member. Death Ridge is a locality that has produced at least one hadrosaurid
(not mentioned in the text) and several other important fossils.
, University of California Museum of Paleontology,
Berkeley, California; , Natural History Museum of
Utah, Salt Lake City, Utah.
DINOSAURIA Owen,
ORNITHISCHIA Seeley,
ORNITHOPODA Marsh,
HADROSAURIDAE Cope,
LAMBEOSAURINAE Parks,
ADELOLOPHUS, gen. nov.
Etymology Adelo (= “unknown,” Greek) + lophus (= “crest,”
latinized from the Greek lophos); meaning “unknown crest,”
in reference to unknown morphology of the skull and crest
of this taxon.
Diagnosis As for type and only species.
ADELOLOPHUS HUTCHISONI, sp. nov.
Etymology Named in honor of Dr. Howard Hutchison,
discoverer of the type specimen and longtime proponent of
southern Utah vertebrate paleontology.
Holotype , a partial maxilla.
Locality and Horizon Wahweap Formation (?Upper
Member), Grand Staircase–Escalante National Monument,
Gareld Co., Utah, United States.
Diagnosis Lambeosaurine hadrosaurid characterized by
the following autapomorphies: maxilla with medial wall of
the anterior process taller than in other lamebosaurines;
maxillary medial wall of posterior process taller than in all
known lambeosaurines, extending up to the dorsal process
and sloping posteroventrally (causally placing the palatine
process well above the position found in other lambeosau-
rines); thickened ridge extending from ventral articulation
of jugal with maxilla posterodorsal to the palatine process.
Description
The isolated maxilla (Fig. .) is incomplete,
with anterior-most and posterior-most regions broken and
missing, along with the most of the ectopterygoid shelf. Iron
oxide–rich sediment covers other portions of the maxilla,
especially the area around the dorsal process and teeth.
Nonetheless, clearly exhibits the diagnostic
lambeosaurine characteristics of a tall and narrow dorsal
process, a well-developed premaxillary shelf, and an overall
triangular shape. In general aspect, it is more similar to Para-
saurolophus spp. maxillae than to lambeosaurin maxillae,
although it is distinctive from the former as detailed below.
The anterior-most region of the maxilla was broken
prior to fossilization as evidenced by the presence of iron
oxide–rich sediment on the broken surface. The remaining
premaxillary shelf predominates the anterodorsal maxilla
as is in other lambeosaurine hadrosaurids. The lateral edge
of the anterior half of the premaxillary shelf is contiguous
with the lateral face of the maxilla, but, more posteriorly, a
small lateral ridge rises and continues onto the dorsal pro-
cess, similar to the condition in taxa such as Corythosaurus
(Sternberg, ), Hypacrosaurus altispinus (Evans, ),
and Parasaurolophus sp. ( .). However, the
medial wall of the premaxillary shelf rises to a higher level
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158 Gates et al.
9.2. Type specimen Adelolophus hutchisoni, UCMP 152028. (A)lateral view; (B)medial view; (C)illustration of lateral view; (D)dorsolateral view; (E)left maxilla
of CPC-59 Velafrons coahuilensis; and (F)UMNH VP 16666.1 maxilla and articulated jugal of Parasaurolophus sp. Note the bi-level structure between the medial
wall and dorsal process and unique raised palatine-jugal ridge in (D). Abbreviations: amw, anterior medial wall; dp, dorsal process; ja, jugal articulation; jp, jugal
process; pjr, palatojugal ridge; pp, palatine process; ps, premaxillary shelf. Scale bars equal 5cm.
than is seen on every other lambeosaurine except Aralosau-
rus tubiferus (Godefroit, Alifanov, and Bolotsky, ). This
species possesses both medial and lateral walls bounding the
premaxillary shelf. Lambeosaurins, on the other hand, have
a much shorter medial wall that, in most cases, rises only a
short distance from the premaxillary shelf and then turns
medially (Sternberg, ; Godefroit, Bolotsky, and Van Itter-
beeck, ; Gates et al., ; Evans, ; Prieto-Márquez
et al., ). Olorotitan is a stark contrast from the other
lambeosaurins with a medial wall that rises in a smooth arch,
but terminates well below the dorsal border of the maxillary
dorsal process (Godefroit et al., ). Parasaurolophs, such
as ., have medial walls that are intermediate
between Adelolophus and typical lambeosaurins. In
, the well-developed medial wall is broken about the
mid-height of the dorsal process. Therefore, the morphology
of the leading edge is unclear for much of its length between
the lower broken edge and a small, presumably complete
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New Hadrosaurid Specimens from the Wahweap Formation 159
section at the same elevation as the dorsal margin of the dor-
sal process. This feature turns medially to a small degree, but
much less so than in Parasaurolophus sp. ( .).
On the dorsal margin of the medial wall, a narrow space is
present between it and the dorsal process that likely would
have clasped the anteroventral margin of the lacrimal.
The dorsal process of the maxilla is the prominent central
feature of , and as in other lambeosaurines, is
dorsally elongated (Horner et al., ). It measures mm
anteroposteriorly at its midpoint, and measures mm from
the maxillary tooth line to the dorsal-most tip of the process.
The morphology of the dorsal region of the dorsal process has
not been discussed in the literature, but is markedly differ-
ent between lambeosaurins and parasaurolophs, with
having the general morphology of the latter group. In
short, lambeosaurins have a sharply tapering dorsal process
(Sternberg, ; Godefroit, Bolotsky, and Van Itterbeeck,
; Prieto-Márquez et al., ; Evans, ; Godefroit et
al., ), whereas Parasaurolophus walkeri ( ) has an
elongated dorsal process body but a rounded dorsal prole,
and . has a shortened, but sub-squared to
rounded, dorsal process. The shape of the Adelolophus dorsal
process is quite similar to that of P. walkeri.
An impression of the jugal articulation facet reveals the
morphology of the ventral portion of the anterior process
of the jugal as dorsoventrally tall and anteroposteriorly nar-
row as in Hypacrosaurus (Evans, ) and Parasaurolophus
(Sullivan and Williamson, ). Based on the comparable
morphology of the narrow ventral region of the anterior jugal
process and the rounded as opposed to sharply tapering dor-
sal process, we speculate that Adelolophus has a jugal mor-
phology similar to Parasaurolophus, where the asymmetrical
anterior jugal process extends a small sharp tapered process
anteriorly over the maxillary dorsal process. Lambeosaurins
have a dorsoventrally symmetrical anterior jugal process
(Evans and Reisz, ; Evans, ; Prieto-Márquez, a).
Posterior to the jugal articulation facet, the palatine pro-
cess rises as a prominent triangular feature, larger in relative
size compared to other lambeosaurines (Sternberg, ;
Godefroit, Bolotsky, and Van Itterbeeck, ; Gates et al.,
; Evans, ; Prieto-Márquez et al., ; Godefroit et
al., ). The size of the palatine process is unknown in para-
saurolophs. In addition to its large relative size, the palatine
process is unique among lambeosaurines in that it originates
from the palatine ridge at approximately % the height of
the dorsal process, and terminates at approximately % the
height of the dorsal process (as measured from the base of the
jugal process to the tip of the dorsal process, . cm). For the
lambeosaurins Hypacrosaurus altispinus (Evans, ), Olo-
rotitan (Godefroit et al., ), and Amurosaurus (Godefroit,
Bolotsky, and Van Itterbeeck, ), the palatine process
reaches a maximum of approximately % of the height
of the dorsal process, based on published specimens such
as H. stebingeri ( ---). Aralosaurus has a rela-
tively low palatine process (Godefroit, Alifanov, and Bolotsky,
), although precise ratios could not be determined from
the literature. The elevated palatine process in
appears to be related to the high medial wall that continues
from the anterior end of the maxilla. No other hadrosaurid
possesses such an elevated posteromedial wall.
Another unique feature of the is a large
thickened ridge that runs posterodorsally from the base of
the jugal articulation facet straight to the palatine process.
The medial wall descends posteriorly to the broken posterior
end of the maxilla. Eroded bone prevents examination of
the most of the posterior region of the bone, including the
ectopterygoid shelf.
The base of the maxilla, excluding the teeth, is slightly
rugose with an inated, well-rounded contour and an acces-
sory protrusion ventral to the dorsal process. This condition
differs drastically from that of North American lambeosau-
rins, which tend to have smooth, tapering bases toward the
tooth rows (e.g., Hypacrosaurus stebingeri ---;
Corythosaurus intermedius ; Velafrons coahuilensis
-), and to a lesser degree in at least one specimen of
Parasaurolophus ( .). The morphology of
is rounded to a greater degree than in
., and the position of the accessory ination underlies
the jugal in the latter specimen. The incompletely preserved
tooth row consists of approximately or tooth positions,
and measures . cm in length.
Medially, does not possess any distinguish-
ing characteristics beyond those related to the features dis-
cussed above. The medial wall dominates the dorsal half
of the element, being mostly dorsoventrally at except for
the anterior eversion along the premaxillary shelf. The row
of nutrient foramina form an arch in the dorsal half of the
element, as in other lambeosaurines.
SAUROLOPHINAE Brown, (sensu
Prieto-Márquez, a)
Gen. et. sp. indet.
Material , partial juvenile skeleton, includ-
ing skull and appendicular elements; elements from the
right side include maxilla, jugal, postorbital, surangular,
scapula, humerus, radius, pubis, ischium, tibia, metatarsal
II, metatarsal IV; elements from the left side include den-
tary, coracoid, ilium, ischium, femur. , partial
adult skeleton comprising cervical vertebrae, dorsal verte-
brae, sacral vertebrae, and anterior, mid-, and distal caudal
vertebrae, ribs, and chevrons; elements from the right side
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160 Gates et al.
9.3. Skull and appendicular elements from UMNH VP 20187. (A)partial left dentary in medial view; (B)right maxilla in lateral view; (C)right jugal in medial
view; (D)left scapula in lateral view; (E)right humerus in posterior view; (F)partial left ilium in lateral view; (G)right pubis in lateral view. Scale bars for (A–C)
equal 5cm. Scale bars for (D–G) equal 10cm.
include postorbital, sternal, ulna, ilium, pubis, tibia, bula,
metatarsal II, metatarsal IV, phalanges IV-2, 3?; elements
from the left side include coracoid, sternal, metacarpals
III and IV, pubis, ischium, femur, calcaneum, astragalus,
phalanges II-2, IV-1, IV-3?; phalanx III-3 from unknown side.
Locality and Horizon Locality ( Locality
), Middle Member, Wahweap Formation, Grand Stair-
case–Escalante National Monument, Gareld Co., Utah,
United States. The site is located m above an altered vol-
canic ash dated to . ± . Ma (Jinnah et al., ).
Comments Two individual saurolophine specimens
were recovered from the site ( Locality ),
a juvenile ( ) and an adult ( )
(see below for discussion of age determination). Skeletal
elements that overlap between the two specimens will be dis-
cussed in tandem, with specic reference to characteristics
not observed on elements of both ages. All skull elements ex-
cept for a partial postorbital are associated with the younger
individual; therefore, characteristics described are subject to
varying degrees of ontogenetic change.
Description
Maxilla The partial juvenile right maxilla does not reveal
substantial taxonomic information (Fig. .B). It is evident
that the low-angled dorsal process is positioned toward the
anterior end of the maxilla, and that the palatine process
is large and separated from the dorsal process by a rel-
atively wide gap. The ectopterygoid shelf is poorly devel-
oped compared to that of maxillae from adult specimens in
other saurolophine species such as Gryposaurus spp. (e.g.,
, ), Prosaurolophus maximus (e.g..,
..) and Edmontosaurus annectens ( ),
although preservation could be a causal factor in the diver-
gent morphology. In lateral view, a dorsally directed, shallow,
and elongated arch denes the ventral ramus of the maxilla
bordering the tooth row.
Jugal The mostly complete right jugal reveals important
anatomical information (Fig. .C). The anterior process is
elongated, as seen in more primitive iguanodontians (Nor-
man, ) and in the saurolophines Acristavus and Maia-
saura (Gates et al., ), and the medial side of the process
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New Hadrosaurid Specimens from the Wahweap Formation 161
has a long, straight articular facet. The posterior portion of
the process constricts to become the jugal neck. The postor-
bital process extends posterodorsally behind the jugal neck.
The inclination of this process is subtle, but based on the
fact that this is a juvenile with a presumably shorter face than
those of adults (Campione and Evans, ), it is likely that
its degree of posterior inclination increases ontogenetically.
And even though inclination of the postorbital process is an
important phylogenetic character, we do not feel compelled
to speculate on phylogenetic signicance of the trait in this
taxon until suitable adult-sized specimens are recovered.
The posterior process of the jugal is wide and expanded,
and in this respect is more similar to species of Gryposau-
rus (Gates and Sampson, ) than to brachylophosaurins
(Gates et al., ). Additionally, the posteroventral ange is
not well developed, as observed in the latter clade. This ele-
ment possesses a unique suite of characters when compared
to currently known hadrosaurid taxa. The only hadrosaurids
known with a similar anterior process, Acristavus and Maia-
saura (Gates et al., ), have a dorsally projecting postor-
bital process that is not inclined, and a well-developed pos-
teroventral ange with a narrow posterior process. Species of
Gryposaurus have a slightly inclined postorbital process and
a wider posterior process with a similarly developed postero-
ventral ange, but lack the long narrow morphology of the
anterior process (Gates and Sampson, ). Saurolophines
closely related to Prosaurolophus (Gates and Sampson, ;
Prieto-Márquez, a; McGarrity, ) do not have any of
these characteristics.
Postorbital Poor preservation in the juvenile and the
adult specimens makes accurate description difcult and
precludes meaningful comparisons with other taxa.
Dentary The incomplete juvenile dentary (Fig. .A)
consists of the posterior region of the bone because the an-
terior portion was broken prior to burial. The few preserved
tooth rows do not extend beyond the coronoid process, which
rises slightly posterodorsally from the main ramus of the den-
tary and then curves anteriorly towards its dorsal terminus.
This exact morphology is not known from other hadrosau-
rids, but again, since this specimen is from a juvenile, its
distinct morphology may represent ontogenetic variation,
rather than an apomorphy. It is evident that the surangular
did not contribute to much of the coronoid process because
the articular facet does not rise to the apex of the process.
The base of the dentary is straight when viewed laterally.
Surangular The body of the right surangular (
) is present, but all processes are broken and the ele-
ment is incomplete. A surangular foramen is clearly absent,
and it appears that the articular would not have been visible
laterally because there is no obvious laterally facing articular
surface for the element.
Cervical Vertebrae Several disarticulated cervical verte-
brae are known from the adult skeleton, but most are not in
good enough condition to warrant detailed description. One
specimen is well preserved (Fig. .A, B), however, and has
a unique morphology not seen in other hadrosaurids. The
centrum is nearly heart shaped, with transverse processes that
extends horizontally from the centrum. The lamina connect-
ing the neural arch and postzygapophyses is nearly straight,
slopes posterodosally, but does not curve posteriorly as in
other hadrosaurid taxa. In general, it is more similar to that
of Iguanodon athereldensis (Norman, ) and Bactrosau-
rus (Godefroit et al., ). Likewise, the postzygapophyses
do not curl posteriorly as in other hadrosaurid taxa (Lambe,
; Lull and Wright, ), giving the entire neural arch
complex a attened appearance as in both I.athereldensis
(Norman, ) and Bactrosaurus (Godefroit et al., ). It
is unclear if the angulation of the aforementioned lamina
maybe skewed dorsally, but there is no evidence of crushing
or plastic deformation of the lamina and postzygapophyses.
The neural spine is anteroposteriorly long but dorsoventrally
short.
Dorsal Vertebrae No complete dorsal vertebrae were
observed during this study. Pieces of neural spine are antero-
posteriorly broad, as expected for a hadrosaurid.
Caudal Vertebrae Anterior caudals have heart-shaped
amphiplatyan centra in anterior view. A strong anteroposte-
rior keel occurs on the ventral surface of each centrum. The
neural spines of all caudal vertebrae, at least midway through
the series, have a wide raised ridge with sharp edges that runs
the entire length of the lateral sides of each spine, creating
anterior and posterior keels. Additionally, the neural spines
are all inclined posteriorly at the base but gradually curve
dorsally (Fig. .C). Spines also increase in anteroposterior
length toward their distal ends, giving them a club-like ap-
pearance as in Bactrosaurus (Godefroit et al., ). Midcau-
dals (Fig. .D) look similar to the anterior caudals, except
that the centrum increases in length and the neural spine
is inclined posteriorly even more so than in Bactrosaurus
(Godefroit et al., ).
Distal caudal vertebrae have a distinctly hexagonal shape
in anterior view with marked corners. Each side of these
vertebrae is slightly indented leaving a raised ridge con-
necting two corners of the anterior and posterior hexagonal
epiphyses. The most unique feature of these vertebrae are
paired foramina on the base of each centrum (Fig. .E, F).
Foramina are common on the bases of hadrosaurid caudal
vertebrae, but the unique characteristic of those in
is that the foramina are always paired and nearly equal
in size. One of us (TAG) has observed large variation in the
size and presence or absence of foramina in the distal cau-
dal vertebrae of every other hadrosaurid species examined,
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162 Gates et al.
9.4. Vertebrae from UMNH VP 13887. (A)cervical vertebra in anterior view; (B)cervical vertebra in A seen in posteroventral view; (C)anterior caudal vertebra in
lateral view; (D)anteromedial caudal in lateral view; (E)distal caudal in ventral view; (F)another distal caudal in ventral view. Scale bars equal 5cm.
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New Hadrosaurid Specimens from the Wahweap Formation 163
except one caudal vertebra in an specimen identied
as Maiasaura (specimen number unrecorded).
Pectoral Girdle includes a partial scap-
ula. The scapula is fairly robust with a triangular acromion
process that is similar in morphology to those of most other
saurolophines, but differs from Gryposaurus monumentensis,
which has a rounded acromion process (Gates et al., ).
The juvenile skeleton preserves a mostly
complete scapula (Fig. .D). In this specimen, the acro-
mion process is the same shape and same relative robustness
as the adult from the same site. Also, the angulation of the
glenoid is also comparable. The scapular blade of the
has a narrow neck and a broad posterior blade. It
is unclear from the preserved adult scapula if the condition
seen in the juvenile is retained into adulthood.
A coracoid associated with is poorly pre-
served (Fig. .A). It contains the coracoid foramen and
a broad contact surface for the scapula. Based on the pre-
served material, it is difcult to determine the angulation
of the glenoid fossa. The ventral process does not extend
beyond the main body of the coracoid as in hadrosaurids
(Prieto-Márquez, a).
Articulated sternals were found associated with
(Fig. .). They look similar to those reported for
Brachylophosaurus (Prieto-Márquez, ) except that the
shafts are shorter. These elements are quite different from
those of Gryposaurus latidens in that the head is rounded
instead of elongated in the latter taxon (Prieto-Márquez, ).
Forelimb Only the juvenile skeleton ( )
preserves a humerus (Fig. .E), which has a characteristic
hadrosaurid shape. Although the humeral head is not pre-
served, it is largely complete. The deltopectoral crest extends
approximately % of the length of the humerus. The dis-
tal condyles lack much denition, but the ulnar condyle is
distinctly larger than the radial condyle.
A single ulna is associated with (Fig.
.C). This element possesses a concave proximal articu-
lation surface, with the wide rounded olecranon process
that ascends for a short distance. The triangular proximal
region tapers into a nearly cylindrical morphology in cross
section at its distal articulation surface. Articulation with
the radius occurs on the lateral side of the ulna in shallowly
concave grooves found on the ulnar head and distal end of
the element.
The single right radius (not gured) found at the site
is from the juvenile skeleton ( ). It is a near
featureless cylindrical element with a lateral bend. The
proximal articulation facet is concave, whereas the distal is
convex.
Left metacarpals () III and IV are preserved in
(Fig. .B). metacarpal III is the longest of the
two bones, and has convex proximal and distal ends. The
lateral side is attened for articulation with metacarpal IV.
A scar two-fths of the way down the anterior shaft marks
the articulation with metacarpal IV. A small scar on the
medial proximal shaft marks the articulation with metacar-
pal II. On metacarpal IV, the proximal end is attened to
slightly convex and laterally expanded. The medial side is at
where it meets metacarpal III. Its distal end is mediolaterally
compressed and convex. Overall, the element tapers distally
throughout its length.
Ilium A complete adult right ilium (Fig. .H) and a
partial juvenile left ilium (Fig. .F) were collected from
the site. The adult specimen shows all characteristics of
hadrosaurids, a long preacetabular process, two lobed ischial
peduncles, and a postacetabular process with no brevis shelf.
The supra-acetabular process is broken. The juvenile ilium
consists of most of the central plate with broken preacetabular
and postacetabular processes, and an ischial peduncle. The
preserved portion of the preacetabular process (Fig. .H) is
typically hadrosaurid in exhibiting an elongate, anteroven-
trally projecting process (Lull and Wright, ; Horner et
al., ). The adult preacetabular process descends below
the level of the peduncles, continuing to curve posteriorly,
which differs from Brachylophosaurus canadensis (e.g.,
) that possesses a straighter process (Prieto-Márquez,
). The dorsal surface of the preacetabular process does
not swell as in other hadrosaurids such as Gryposaurus nota-
bilis ( ) or Saurolophus osborni ( ). A large
shelf overhangs the lateral side of the preacetabular process
in the juvenile specimen, closely resembling that found on
G.monumentensis ( ), but which is not present
on the adult specimen. The central plate is at and relatively
narrow. The supra-acetabular process was not well developed
in this individual or was poorly preserved. Posteriorly, the
postacetabular process of the adult ilium has subparallel
dorsal and ventral margins with a slightly pointed terminal
margin; in contrast, that of the juvenile has a more primitive
triangular morphology, again more similar to G.monumen-
tensis ( ) than to other saurolophines including
G.notabilis (e.g. ).
Pubis A left and right pubis is known from
(Fig. .I), and a right pubis is present in
(Fig. .G). The morphology is generally typical
for saurolophines: pubic blade with a short neck and an
elongated anterior process (blade) that is dorsoventrally ex-
panded. As in Gryposaurus latidens (Prieto-Márquez, )
and Gryposaurus notabilis ( ), the blade of the adult
has subparallel dorsal and ventral margins, with the dorsal
margin being expanded and the ventral margin connecting
seamlessly to the neck of the blade. The juvenile and the
adult pubes differ drastically in morphology of the pubic
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164 Gates et al.
9.5. Appendicular elements from UMNH VP 13887. (A)left coracoid in medial view; (B)left metacarpals II and III in anterior view; (C)right ulna in posterior
view; (D)left femur in lateral view; (E)right metatarsal II in lateral view; (F)right metatarsal IV in anterior view; (G)left ischium in lateral view; (H)right ilium in
lateral view; (I)left pubis in medial view. Scale bars for (A), (B), (E), and (F)equal 5cm. Scale bars for (C) (D), (G), (H), and (I)equal 10 cm.
9-Hadrosaurs Ch9 (154-73).indd 164 8/28/14 1:22 PM
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New Hadrosaurid Specimens from the Wahweap Formation 165
9.6. Sternals from UMNH VP 13887. (A)sternals prepared in jacket as found in quarry; (B)sternals pictured in quarry shown in original articulation. Scale bar
equals 10cm.
9-Hadrosaurs Ch9 (154-73).indd 165 8/28/14 1:22 PM
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166 Gates et al.
blade. In the ventral margin – and therefore
the distal end of the blade – is deected ventrally, and the
dorsal expansion of the blade is more subtle and spread out
along the dorsal margin. A morphology almost identical to
this is seen in G. monumentensis ( ). The
blade morphologies demonstrated on specimens from
are not comparable to other hadrosaurs outside of the genus
Gryposaurus.
Ischium includes a nearly complete left
ischium (Fig. .G), and includes a partial
right and left ischium. Little can be said about the juvenile
specimens because of poor preservation, so this discussion is
based on the adult specimen ( ). The iliac pe-
duncle is anteroposteriorly compressed slightly, whereas the
pubic peduncle is not well enough preserved to warrant de-
scription. The obturator process is broken, so it is unknown if
this feature is closed as in more primitive iguanodontians or
open as in hadrosaurids. A straight ischial shaft swells slightly
in the center, but does not preserve the distal tubercle. This
element does not differ signicantly from other saurolophine
ischia (e.g., Prosaurolophus maximus ; Gryposaurus
notabilis ).
Hindlimb Both (Fig. .D) and
have an associated left femur. The adult specimen has a
greater trochanter that is well offset from the femur. The
fourth trochanter in the same specimen has a distinctly tri-
angular shape. Its apex is set to ventral end of the trochanter.
Also, the base of the trochanter is connected to the femur
within a depression on the femoral shaft. Brett-Surman and
Wagner () suggested that there was a large amount of
variation between individual hadrosaurid femora, and we do
not make further comparisons here.
Both and preserve a right tibia, and
the latter preserves a right bula. These elements are not
identiably different from the corresponding elements of
other hadrosaurids and are not discussed further.
Pes The proximal end of a right metatarsal II from
(Fig. .E) is more anteroposteriorly elongated than
wide, and its medial side is concave. A sharp ridge is present
on the anterior surface near the articulation with metatarsal
III. Its distal end is wide. A right metatarsal IV (Fig. .F)
from the same specimen shows a proximal articulation sur-
face that is concave. Again, the medial surface of the proxi-
mal end is concave to receive metatarsal III, as is the surface
at the distal end. Two-fths of the way down the medial sur-
face there is a large, attened protuberance resembling the
condition described in Brachylophosaurus (Prieto-Márquez,
). The general characteristics of these metatarsals are
also present in other hadrosaurids (Parks, ; Lull and
Wright, ; Horner et al., ; Brett-Surman and Wagner,
; Prieto-Márquez, ). Numerous manal and pedal
phalanges have been recovered from both the juvenile and
adult skeletons. These lack any diagnostic traits and are not
discussed further. Preserved unguals are hoof-like, but lack
a ventral keel (sensu Prieto-Márquez, a).
Femoral Histology and Ontogenetic Status of
20187
The left femur of was thin-sectioned and
analyzed to assess the ontogenetic age of the individual. Poor
preservation did not allow preparation of histological samples
from the larger specimen. The femur length () of the
smaller individual ( ) is . cm. Based on size,
this suggests that it is a late juvenile ( = cm) or subadult
( = cm) if we assume this taxon has a size/ontogenetic
stages relationship comparable to Maiasaura peeblesorum
(Horner et al., ); however, size does not always correlate
precisely with age, so size-independent criteria such as bone
histology are best for assessing ontogenetic stages (Johnson,
). We sectioned the femur at midshaft (circumference,
. cm), cm from the distal end. The medullary cavity is
mm in diameter. There is very little preserved cancellous
bone (Fig. .), but the preserved trabeculae are composed
of unordered primary bone. Visible in cross-polarized light,
woven bone dominates the inner and middle cortex. The
tissue structure in the inner cortex nearest to the medullary
cavity can best be described as unordered. The vascular
canals are small and longitudinal. The vascular canals are
very dense throughout the inner cortex of the bone and ori-
ented slightly radially. Both of these features are evidence of
fast growth (deMarerie et al., , . The bone tissue is
dominated by primary osteons that are very dense throughout
the inner cortex (Fig. .), whereas secondary osteons are
rare, being limited to a remodeled area of biomechanical
stress located ventral to the fourth trochanter, which is the
m.caudofemoralis attachment. This limited presence of sec-
ondary osteons is typical of the late juvenile growth stage in
the saurolophine Maiasaura (Horner et al., ). Nearer
to the periosteum, the tissue becomes more ordered, with
dense but reticular vascular canals.
Lines of arrested growth (s) do not appear regularly
in hadrosaur long bones until they are half grown (Cooper
et al., ). does not preserve any s or
identiable “rest lines.” Thus, there are two alternative in-
terpretations for the histology preserved in this specimen: it
is possible that this animal was growing so fast that it did not
deposit s; or the individual may have been no more than
a year old when it died. It is difcult to discern between the
two alternatives using histological data. The bone also lacks
any evidence of an external fundamental system, a feature
that indicates the near cessation of skeletal growth in adult
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New Hadrosaurid Specimens from the Wahweap Formation 167
9.7. Thin-section of UMNH VP 20187 taken at the midshaft of the femur,
with magnification of inner cortex.
animals (Horner et al., ). Lastly, there is no evidence
in the external cortex of lamellar-zonal bone, indicative of
slowing growth, as found in adult Maiasaura (Horner et al.,
). In summary, although this animal lacks s that
would allow us to assign a minimum age, we conclude that
this animal was growing rapidly when it died on the basis
of the dense radial and reticular vascular canals, and tissue
dominated by primary bone.
When compared with the femur histology of an adult
specimen of Hypacrosaurus stebingeri ( , =
cm; Horner et al., ), does not preserve
any adult characters. Secondary osteons dominate the inner
and outer cortex (Horner et al., ), contrary to
, with a cortex that is dominated by primary osteons.
Furthermore, the femur of preserves at least eight
s and an external fundamental system (Horner et al.,
). Because has a considerably smaller
femur length (. cm), no s, a lack of an external fun-
damental system, and vascular evidence for sustained contin-
ued rapid growth, it does not represent an adult individual.
The femur length compared with those from Maiasaura pee-
blesorum (Horner et al., ) suggests that the ontogenetic
stage of this animal was somewhere between late juvenile
and subadult. However, a comparison of bone microstruc-
tures between and M.peeblesorum indicates
that shares more histological similarities to
the juvenile stage of M.peeblesorum. Thus, we hypothesize
that this animal was young but almost certainly more than
one year old, despite the lack of growth lines. Of course, this
age estimate is based on an assumption that the
grew at the same rate as Maiasaura. Such an assumption
is speculative given the differences observed between the
Horner et al. () analysis and histological results from
.
Taxonomic Identication
The juvenile ( ) and adult ( )
within the site are tentatively referred to the same taxon,
but this assumption is complicated by differences in the mor-
phology of the pubis and ilium. The shape of these bones
differs markedly between the two individuals, and thus could
be evidence for a species-level distinction. However, all other
shared elements exhibit a typical hadrosaurid morphology,
thus providing no additional evidence for these being differ-
ent taxa.
If these skeletons are assumed to be from the same spe-
cies, which seems likely given that they are from the same
site, then the postcranial skeletons found at the site can
be diagnosed by a unique combination of characters and
possible autapomorphies: straight ventral margin of jugal
anterior process; moderately expanded jugal posteroventral
ange; cervical vertebrae with posterodorsally and medi-
olaterally expanded neural lamina; anterior and mid-cau-
dals with neural spines that are posterodorsally curved and
broader dorsally than at the base; and distal caudal vertebrae
with paired subequal sized foramina on their ventral surface.
Despite this suite of characters, we do not feel compelled to
name a new taxon in the absence of adult cranial material
and the aforementioned pubic differences.
Most of the traits present in the juvenile skull, including
the triangular anterior jugal process and the moderate size
9-Hadrosaurs Ch9 (154-73).indd 167 8/28/14 1:22 PM
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168 Gates et al.
of the posteroventral ange would likely have been retained
into adulthood; similar regions are ontogenetically stable in
Hypacrosaurus stebingeri and Maiasaura peeblesorum (TAG,
pers. obs.). Both of these traits are primitive among iguano-
dontians (Norman, ), with the former also found in the
hadrosaurids Acristavus (Gates et al., ) and Maiasaura
(Horner, ; Gates et al., ). However, unlike the latter
two taxa that demonstrate a well-offset posteroventral ange,
the ange in shows a relatively conservative
morphology. The morphology of the maxilla likely changed
through ontogeny; and given the fact that the small element
does not preserve many informative characters, we do not
use it in our taxonomic assessment. Another useful trait is
the presence of a long ectopterygoid shelf, which is found in
Hadrosauridae (sensu Prieto-Márquez, a).
The partial ilium of the juvenile is also difcult to inter-
pret, because the morphology of this element likely changed
through ontogeny. However, this bone is quite similar to
that in Gryposaurus monumentensis, which has autapomor-
phic traits that include a shortened, non-tapering, and robust
preacetabular process, as well as a markedly triangular posta-
cetabular process (Gates et al., ). Although not necessar-
ily unique, the dorsal margin of the iliac plate is at between
the anterior and posterior processes and is, thus, unlike other
iguanodontians (hadrosaurids included) that have either a
swelling or depressions in this area (Prieto-Márquez, a;
Gates et al., ).
The adult ilium is more similar to those of other hadro-
saurids, and aside from subtle differences in the degree of
dorsal expansion of the preacetabular process and depth of
the iliac plate, is not diagnostic to the species level within
Hadrosauridae. An ilium is not known for either the Utah or
Montana specimens of Acristavus.
The pubis of is nearly identical to the
pubis of G.monumentensis (Gates et al., ) whereas
is similar to G.notabilis ( ; Parks, ) and
Maiasaura ( ..). The preserved pubis on the
type specimen of Acristavus ( ) is not complete, but
the proximal portion of the prepubic process is similar to
that of the latter taxa. No other iguanodontians possesses the
combination of morphological traits described here, includ-
ing Acristavus gagslarsoni, which is currently the only named
saurolophine from the Wahweap Formation.
The possible autapomorphic traits present on the caudal
vertebrae of are here tentatively accepted as
such. That said, the shape of the anterior and middle caudal
neural spines (Fig. .C, D), and the nature and distribution
of foramina on the ventral surface of the distal caudals (Fig.
.E, F) are not well understood for other iguanodontians
(see above) because comparatively little emphasis has been
placed on the morphology of caudal vertebrae in general. So,
although the foramina exhibit unique morphologies per the
specimens and taxa examined by Gates, there is a dearth of
comparative information about this feature in the literature
(cf., Godefroit et al., ). Accordingly, more research is
needed before the morphology of is accepted
as unique.
Phylogenetic Analyses
In order to inform the taxonomic assignment of the hadro-
sauroid material described above, two phylogenetic analyses
were run on the material, one analysis of only the adult
material from (Fig. .A) and the second
with all material from (Fig. .C). The character set
of Gates et al. () was used as the basis of the analyses,
with the inclusion of material ( , of
characters scored; , of characters
scored; for scorings see Appendix .). The nal data matrix
consisted of characters and taxa. TnT v.. (Goloboff
et al., ) was used to analyze the data matrix. Iguanodon
was considered the outgroup taxon, and all characters were
unordered.
The analysis resulted in the recovery of two most parsimo-
nious trees ( tree score) when only the adult material was
considered. In one of the most parsimonious trees, the
taxon is placed one node above Iguanodon at the base of the
tree (Fig. .A). The second most parsimonious tree placed
the within the Prosaurolophus-Saurolophus clade
(Fig. .B). The large disparity in phylogenetic hypotheses
demonstrates that the recovered skeletal material of the adult
specimen is a mélange of both primitive and derived traits,
as might be expected in an Early to Middle Campanian
hadrosauroid.
With both the juvenile and adult skeletal material scored
as a single , a single most-parsimonious tree ( tree
score) was obtained. In this case, the is placed
above Telmatosaurus and below Corythosaurus, thereby form-
ing the sister taxon of Hadrosauridae (senso Prieto-Márquez
[a]; Fig. .C). Given the unclear ontogenetic trajectory
of the skull elements used to produce the phylogenetic tree
in Figure .C, the placement of the remains
unknown within the greater context of hadrosauroids. This
analysis remains difcult to interpret because juvenile indi-
viduals of a given taxon will often be recovered in a more
basal systematic position than their corresponding adult (e.g.,
Tsuihiji et al., ). does possess two ambig-
uous synapomorphies of Hadrosauridae as dened by Prie-
to-Márquez (a): coracoid reduced in size relative to the
scapula ([]), and recurved and caudoventrally directed
ventral process of the coracoid ([]). The coracoid shows
the only synapomorphies of Hadrosauridae, but there are
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New Hadrosaurid Specimens from the Wahweap Formation 169
9.8. Phylogenetic trees showing relationships of hadrosaurids discovered
in WBH quarry. (A)first of two most-parsimonious trees produced from
matrix of only adult skeletal material (tree length 204); (B)second of two
most-parsimonious trees produced from only adult WBH material (tree length
204); (C)tree produced from matrix of juvenile and adult material (one tree
produced; tree length 210). Matrices are based on that published by Gates et
al. (2011). See text for details.
other characters in which this bone is too poorly preserved
for us to accurately gauge ratios or make interpretations of
relative size. Elements such as the large scapula are too
poorly preserved to allow us to condently identify other
synapomorphies, and the presumed juvenile elements from
are not considered here.
Taphonomy of the
Locality
The site, Locality , is one of the most
signicant sites yet discovered in the Wahweap Formation
because it contains the most complete hadrosaurid skeletons
known from this unit, comprising two individuals of different
ontogenetic age. The geology and taphonomy of the
site was studied in order to understand the factors that re-
sulted in the deposition of this unique assemblage.
The middle member of the Wahweap Formation consists
largely of ne-grained (claystone-siltstone) oodplain depos-
its, which can be interpreted as the deposits of swamps, ox-
bow lakes, and waterlogged soils. Isolated channel-sandstone
bodies form a subordinate component of the middle member
(Jinnah and Roberts, ). The site occurs in a later-
ally extensive bed of mudrock, interpreted as a distal-ood-
plain deposit resting approximately m above the . Ma
ash bed of Jinnah et al. (). Horizontal laminations in
the mudrock – together with crab claws, sh scales, plant
hash, and coal stringers – indicate subaqueous deposition in
a low-energy oodplain pond. The abundant presence of
taxodiaceous leaves further supports this interpretation. In
addition to these features, close to one dozen coalied trees
were observed crisscrossing the quarry deposit, with bones ly-
ing only millimeters above them. Directional data gathered
from elongate bones (Fig. .) were recorded and analyzed
using one-sample directional statistics in v. . (Ham-
mer et al., ). The mean orientation of these elements
is ° relative to north. The resultant Rayleigh statistic of
. suggests probability of random distribution at .,
well outside the % condence interval, and resulting in
an interpretation of uniform distribution. However, a χ2 test
of the directional data calculated from eight bins shows the
probability of uniform distribution at ., a result con-
sistent with a slightly preferred directionality for the
long bones. According to Hammer and Harper () an
instance of failing to reject the null hypothesis in a Rayleigh
test but rejecting the null hypothesis in a χ2 test should be
interpreted as an indication of multiple preferred directions
within a dataset, although not uniform distribution. Visual
inspection of the rose diagrams shows a bimodal distribution
of elements. Elongate bones at the site are generally aligned
exhibiting either a northeast-southwest trend or, less com-
monly, a northwest-southeast trend. Even though bimodal
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170 Gates et al.
9.9. Quarry map from WBH, UMNH VP Locality 324. Left side marks edge of
quarry facing hill. Remaining sides are open faces. Upper rose diagram shows
unidirectional orientations (east) of all long bones found in the WBH locality.
Lower rose diagram shows paleocurrent directions derived from cross-bedded
sandstones in the Middle Member of the Wahweap Formation.
Signicance of Adelolophus
Albeit a single element, clearly is differentiable
from all other known hadrosaurid maxillae. It is interpreted,
therefore, as representing a new taxon. Adelolophus hutchi-
soni is not the rst new lambeosaurine to be recognized on
the basis of a single, isolated maxilla. Wagner and Lehman
() described Angulomastacator daviesi on material of
similar completeness. Distinguishing between species of
closely related taxa may be a concern when establishing a
new taxon using a single element (such as a maxilla). How-
ever, at least two species of Parasaurolophus (P.walkeri
and an unidentied species from the Kaiparowits For-
mation) have quite distinct maxilla morphology (TAG, pers.
obs.). Thus, we conclude that the combination of unique
characteristics present in and the known spe-
cies-level variation in maxillary morphology observed within
other lambeosaurine taxa warrants the establishment of
A.hutchisoni.
The precise stratigraphic provenance of is
not known for certain. However, assuming that it came from
the Upper Member of the Wahweap Formation, which is the
stratigraphically highest fossiliferous member of the forma-
tion, we may still conclude that this maxilla represents the
earliest denitive lambeosaurine skeletal material yet known
from North America (~ Ma based on dates in Jinnah et
al. []).
The morphology of shows that all of the
denitive morphological features that characterize lambeo-
saurine maxillae – as well as all other skull modications
correlated with the maxillary characters – were present by
the middle Campanian. This evidence does not support or
refute the proposition that Lambeosaurinae and Sauroloph-
inae diverged from a common ancestor during the Santo-
nian, as recently set forth by Prieto-Márquez (b). Yet if
evidence is ever found of lambeosaurine skeletal material
of such a derived grade as in within the lower
portions of the Wahweap Formation (close to Ma [Jinnah
et al., ]), then closer scrutiny will have to be paid to
the timing and geography of the phylogenetic split between
Saurolophinae and Lambeosaurinae.
Locality Behavioral Implications
Does the discovery of two hadrosaurid individuals of different
sizes and ontogenetic ages at one site (containing no
other macrovertebrate remains) constitute evidence for intra-
species social behaviors (parent-juvenile interactions or herd-
ing) in hadrosaurids? We conclude that such intraspecies
distributions (such as this) are credited to shallowly owing
water, there is minimal evidence at the site for such ow, so
this causal agent must be considered only a tentative possibil-
ity. Nonetheless, a northeast ow is consistent with the over-
all paleocurrent direction for the Wahweap Formation based
on paleocurrent data collected from trough cross-bedding
in channels (Fig. .). Just above the fossiliferous horizon
there is at least m of oodplain mudrock, suggesting that
a relatively long-lived oodplain was established at the site
at the time of deposition.
Preburial condition of bones seems relatively good,
with only minor predepositional breakage (% of ribs
and % of vertebrae), minimal evidence for subaque-
ous abrasion, and no evidence of tooth marks. Based on
the ne-grained nature of the matrix, the lack of major
current alignment, and the lack of subaqueous abrasion
on the bones, the fossil assemblage is interpreted
as autochthonous, with the two hadrosaurid individuals
likely dying at the site and, subsequently, disarticulating via
decomposition, current action in calm to slightly owing
water, and, possibly, scavenging.
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New Hadrosaurid Specimens from the Wahweap Formation 171
social behaviors cannot be inferred from this assemblage
for the following reasons. First, it remains unclear whether
the two specimens are from the same species. With further
discoveries of more complete remains, this problem may
be remedied. Second, and assuming that the specimens are
from the same species, all social behaviors – such as herd-
ing, parent-offspring bonding, etc. – that could possibly be
elicited to explain the presence of these two hadrosaurid
individuals in a fossil site, require evidence of those behaviors
(not preserved), and some form of evidence that the two indi-
viduals at least died at the same time (and thus lived at about
the same time). In fact, direct evidence of such behaviors and
time of death are rarely preserved at fossil localities. Despite
previous attempts to reconstruct hadrosaurid sociality using
taphonomic evidence (Horner and Makela, ; Fiorillo,
; Horner, ; Varricchio and Horner, ), we feel
that the site does not provide sufcient evidence to infer
hadrosaurid social interactions.
Wahweap Hadrosaurid Diversity
Based on the present report and Gates et al. (, ), there
are a minimum of four hadrosaurid taxa known from the
Wahweap Formation. These include Acristavus gagslarsoni
(Gates et al., ), Adelolophus hutchisoni, the ,
and a new species based on a partial skeleton from the Up-
per Member ( ; Gates et al., ). The latter
specimen is similar to Brachylophosaurus canadensis but
distinct from Acristavus and the . Even though at
least three of the specimens are known to be stratigraphically
well separated from one another (see Fig. .), too few spec-
imens are known from the Wahweap Formation to provide
meaningful stratigraphic ranges for the taxa they represent.
Nonetheless, the notion that these hadrosaurids do not over-
lap in time may have some validity based on biostratigraphic
comparisons with dinosaur-rich sections of similar age in
Montana. Specically, Acristavus in southern Utah occurs
in strata that are chronostratigraphically equivalent to those
that host the type specimen of this same species in Montana.
In both cases, these strata are stratigraphically distinct from
those containing Brachylophosaurus. Similarly, a saurolo-
phine maxilla, , occurs at a level similar in
age to those strata that host Brachylophosaurus in Montana.
Such data, limited though they may be, suggest that the
preliminary biostratigraphic pattern emerging from the Wah-
weap Formation does not differ from that documented in the
better-sampled sections in the northern part of the Western
Interior Basin.
We thank the following people: Howard Hutchison for his
work collecting and allowing us to study this
specimen; Pat Holroyd for allowing the specimen on loan to
the ; Grand Staircase–Escalante National Monument
staff, especially Alan Titus, for funding, permitting, logistical,
excavation assistance, and the helicopter expedition that led
to the discovery of the site; Scott Foss and Laurie Bryant
from the Utah for permitting; Scott Sampson for the
creation and preservation of the Kaiparowits Basin Project;
Eric Lund, Utah Friends of Paleontology, volunteers,
and all others who helped excavate and prepare the skeletal
elements from the site; Randy Irmis for permission to
histosection material. Albert Prieto-Márquez provided
comparative images and publications. Virginia Greene pro-
vided the illustration of . Helpful reviews pro-
vided by David Evans and Derek Larson greatly increased
the strength of the chapter. Funding was provided by the
National Science Foundation, the Bureau of Land Manage-
ment, Geological Society of America Research Grant (),
Arthur J. Boucot Award–Paleontological Society Student
Research Grant (), and the Grand Staircase Institute of
Science Student Research Grant ().
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Appendix 9.1. Character Codings for the Skeletal Material Recovered from the WBH Site
Adult only (UMNH VP 13881) ?????????? ?????????? ?????????? ?????????? ?????????? ?????????? ?????????? ?????????? ???11??1?0
????????11 ??1101111? ?0??11
All elements (UMNH VP 20187
and UMNH VP 13881)
?????????? 0???????10 ?????????? ?????????? 1?1210??10 000110001? ?????????? ?????????? ???11??1?0
11??10??11 ?01101111? 10??11
Note: Codings are based on the phylogenetic matrix of Gates et al. (2011).
9-Hadrosaurs Ch9 (154-73).indd 173 8/28/14 1:22 PM
Copyrighted Material. (c) 2014 Indiana University Press. All Rights Reserved.
