A high latitude vertebrate fossil assemblage from the Late Cretaceous of west-central Alberta, Canada: evidence for dinosaur nesting and vertebrate latitudinal gradient

Abstract

This study reports on a new microvertebrate locality from the Campanian (c 74 My) fluvial beds of the Wapiti Formation in the Grande Prairie area (west-central Alberta, Canada). This locality represents deposition on a low-gradient, waterlogged alluvial plain approximately 300 km to the north west of the Bearpaw Sea. Detailed sedimentological analyses suggest an environment characterized by a high-sinuosity channel system responsible for widespread oxbow lakes, bogs and marshes. A total of 260 identifiable elements were recovered from three distinct sites at the Kleskun Hill Park, documenting a diverse terrestrial and fresh-water palaeocommunity. The recovered fossils include those from hatchling- to nestling-sized hadrosaurid dinosaurs, indicating the presence of a nesting ground in the area. This is the first evidence for dinosaur nesting site in the Wapiti Formation and simultaneously an extremely rare evidence of high-latitude dinosaur nesting, the northernmost in North America to date. A large number of teeth of the small theropod Troodon are associated with baby hadrosaurids in the site supporting a northern affinity of this taxon as well as a previously proposed predator–prey association. Other dinosaurs are less common at the locality and include large and small theropods (i.e. tyrannosaurid, Saurornitholestes, Richardoestesia, Paronychodon, and dromaeosaurid) and five ornithischian taxa. Fish, squamate, turtle, and mammal elements were also identified. Collectively, the vertebrate fossil assemblage from the locality allows palaeocommunity reconstruction in the Wapiti Formation. The importance of the data collected from the new locality is twofold: first, they represent the first comprehensive report from a geographically significant area located between the well-sampled fossil localities of southern Alberta and the high-latitude localities of Alaska. Furthermore, the reconstructed vertebrate fauna support latitudinal gradient of vertebrate distribution along the Western Interior region during the Late Cretaceous.

Full text

A high latitude vertebrate fossil assemblage from the Late Cretaceous of
west-central Alberta, Canada: evidence for dinosaur nesting and
vertebrate latitudinal gradient
Federico Fanti
a,
⁎, Tetsuto Miyashita
b
a
Dipartimento di Scienze della Terra e Geologico-Ambientali, Alma Mater Università di Bologna, Via Zamboni 67, 40126 Bologna, Italy
b
Department of Earth and Atmospheric Sciences, University of Alberta, 126 Earth Science Building, Edmonton, Alberta, Canada T6G 2E3
abstractarticle info
Article history:
Received 18 October 2008
Received in revised form 4 February 2009
Accepted 6 February 2009
Keywords:
Wapiti Formation
Palaeoecology
Palaeocommunity
Microvertebrate fossil
Campanian
Dinosaur nesting
This study reports on a new microvertebrate locality from the Campanian (c74 My) fluvial beds of the Wapiti
Formation in the Grande Prairie area (west-central Alberta, Canada). This locality represents deposition on a
low-gradient, waterlogged alluvial plain approximately 300 km to the north west of the Bearpaw Sea.
Detailed sedimentological analyses suggest an environment characterized by a high-sinuosity channel
system responsible for widespread oxbow lakes, bogs and marshes. A total of 260 identifiable elements were
recovered from three distinct sites at the Kleskun Hill Park, documenting a diverse terrestrial and fresh-water
palaeocommunity. The recovered fossils include those from hatchling- to nestling-sized hadrosaurid
dinosaurs, indicating the presence of a nesting ground in the area. This is the first evidence for dinosaur
nesting site in the Wapiti Formation and simultaneously an extremely rare evidence of high-latitude
dinosaur nesting, the northernmost in North America to date. A large number of teeth of the small theropod
Troodon are associated with baby hadrosaurids in the site supporting a northern affinity of this taxon as well
as a previously proposed predator–prey association. Other dinosaurs are less common at the locality and
include large and small theropods (i.e. tyrannosaurid, Saurornitholestes,Richardoestesia,Paronychodon, and
dromaeosaurid) and five ornithischian taxa. Fish, squamate, turtle, and mammal elements were also
identified. Collectively, the vertebrate fossil assemblage from the locality allows palaeocommunity
reconstruction in the Wapiti Formation. The importance of the data collected from the new locality is
twofold: first, they represent the first comprehensive report from a geographically significant area located
between the well-sampled fossil localities of southern Alberta and the high-latitude localities of Alaska.
Furthermore, the reconstructed vertebrate fauna support latitudinal gradient of vertebrate distribution along
the Western Interior region during the Late Cretaceous.
© 2009 Elsevier B.V. All rights reserved.
1. Introduction
Microvertebrate localities from both marine and non-marine deposits
are a powerful tool for the study of palaeoecology and palaeobiogeo-
graphy. They represent a rich source of information on local biota and are
useful in addressing a variety of questions in palaeoecology (Sankey,
2008a). This study is a preliminary report on a new Campanian micro-
fossil locality from the Wapiti Formation beds exposed at the Kleskun Hill
Park (Grande Prairie area, west-central Alberta, Canada), and the first
attempt to document the terrestrial taxa in the formation during the
maximum transgression of the Bearpaw Seaway in the Late Cretaceous.
High-resolution sedimentological data and an analysis of the hetero-
geneous fauna were combined to estimate the local biodiversity and the
relative abundance of selected groups of vertebrates. In so doing, we
focused primarily on faunal composition and comparison, and address
implications on environmental factors that characterized the fauna also
on the light of the proposed north–south biozonation of vertebrate taxa
during the Campanian in western North America (Brinkman, 1990;
Eberth, 1990; Eberth and Brinkman, 1997; Ryan et al., 1998; Fiorillo and
Gangloff, 2000; Lehman, 2001; Sankey, 2001; Brinkman et al., 2004,
2007; Baszio, 2008; Sankey, 2008a; Wilson, 2008).
This paper consists of three parts: 1) a detailed description of
stratigraphic, sedimentological, and palaeocological signatures at the
Kleskun Hill; 2) a statement of the diversity of the vertebrate
assemblage recovered; and 3) a discussion on the implication of this
locality on latitudinal gradient of vertebrate distribution in the
Western Interior during the Late Cretaceous.
2. Geographical and geological setting
The Kleskun Hill Park area is located approximately 25 km
northeast of Grande Prairie (west-central Alberta) on the left side of
Palaeogeography, Palaeoclimatology, Palaeoecology 275 (2009) 37–53
⁎Corresponding author. Tel.: +39 051 2094565; fax: +39 051 2094522.
E-mail address: federico.fanti@unibo.it (F. Fanti).
0031-0182/$ –see front matter © 2009 Elsevier B.V. All rights reserved.
doi:10.1016/j.palaeo.2009.02.007
Contents lists available at ScienceDirect
Palaeogeography, Palaeoclimatology, Palaeoecology
journal homepage: www.elsevier.com/locate/palaeo

the Smoky River (Fig. 1). Discontinuous badlands exposures, the most
northern occurrence of this peculiar geomorphology in Alberta
(Byrne, 1955), rise up to 100 m above surrounding plains over an
area of 16 km
2
. The Kleskun Hill badlands have been considered for
years as the richest fossil locality in the Grande Prairie area: hundreds
of disarticulated hadrosaur bones and other dinosaur remains
collected in the 1940s were referred to an unknown locality within
the area (Tanke, 2004). However, to date the locality has been neither
mapped nor documented and a description of squamate jaws by
Sternberg (1951) is the sole published work on the Kleskun Hill fossils.
The first geological report on the Kleskun Hill was made by Allan
and Carr (1946) who tentatively correlated the exposures to the lower
Edmonton Formation southeast to the area. However, data from
geophysical well logs of exploration boreholes indicate that strata
exposed at Kleskun Hill Park lie approximately 340 m above the base
of the Wapiti Formation, within a lithostratigraphic unit characterized
by medium to high accommodation conditions, decimetre-to-metre
thick bentonitic layers, and well developed, tabular coal seams (Fanti,
2007). This unit is considered an inland equivalent of the Bearpaw
shale of central and southern Alberta, rather than that of the lower
Edmonton Group (i.e. Horseshoe Formation). Supporting this correla-
tion is a 20 cm thick, olive volcanic ash layer located in the lowermost
section of strata exposed in the park (Fig. 2) which yielded a
40
Ar/
39
Ar
age of 73.77± 1.46 My (Eberth, in Fanti, 2007). This age is roughly
equivalent to the maximum transgression of the Bearpaw Seaway in
central and southern Alberta (Baculites compressus zone, 73.4 My;
Obradovich, 1993). Therefore, the Kleskun Hill palaeofauna is a rare
terrestrial fossil assemblage from a stratigraphic interval represented
by marine deposition elsewhere in western Canada and north-
western United States. Furthermore, the Wapiti fossil record is
geographically important, as the locality is between the deposits of
southern Alberta and the high-latitude fossil localities of Alaska (the
present day distance is in the range of 400 km north and 3200 km
south respectively; Parrish et al., 1987; Fiorillo et al., 2007).
Palaeogeographic reconstruction for the late Campanian of North
America place the southern Alberta localities (Belly River Group) at
about 58°N palaeolatitude, the Grande Prairie localities at approxi-
mately 65°N palaeolatitude (Scotese, 1991; Brinkman, 20 03), and the
Fig. 1. A, reference map of Alberta (Canada) showing the extension of the Campanian–Maastrichtian Wapiti Formation. B, location of the study area northeast of Grande Prairie. Sites
A, B, and C are located within the Kleskun Hill Park area. Contour lines elevation data are expressed in metres. S–S′, cross section shown in Fig. 2.
38 F. Fanti, T. Miyashita / Palaeogeography, Palaeoclimatology, Palaeoecology 275 (2009) 37–53

Alaskan localities between 75° and 85°N latitude (Smith and Briden,
1977; Ziegler et al., 1983; Witte et al., 1987). Therefore, in this study
the Kleskun Hill Park assemblage is referred to as high latitude.
3. Materials, methods, and institutional abbreviations
For this study, the Kleskun outcrops were prospected from 2004 to
2008. This led to the identification of three restricted areas where
erosive processesand surface hydraulic transportationhad concentrated
vertebrate remains. Thesespots will be referred to in the text and figures
as Sites A, B, and C. Detailed outcrop analyses resulted in a composite
cross-section of the study area (S–S′,Fig. 2) that permitted to document
reciprocal stratigraphic occurrence of fossiliferous sites. Colours used for
sedimentological descriptions follow the Munsell Soil Colour Chart.
Following discovery of fossils fromthe surface of theoutcrop, a 4 m
2
area was excavated in 2004 at Site B by the field crew of Royal Tyrrell
Museum of Palaeontology (Drumheller, Alberta, Canada). Sandy and
silty sediments to the depth of 40 cm werecollected for screen washing
(sieves of 1 mm). With about 90% of the collected matrix screened and
sorted, 29 specimens have been identified. In addition to this, surface
collection at Sites A, B, and C yielded 231 identifiable specimens (for a
total amount of 260 specimens), primarily theropod teeth and hadro-
saurid postcranial and teeth fragments.
The collected specimens were primarily identified and compared
with those from the well-described Campanian–Maastrichtian verte-
brate fossil assemblages in southern Alberta (Brinkman, 1990; Currie
et al., 1990; Brinkman and Neuman, 2002; Eberth et al., 2001; Sankey
et al., 2002). Identification of hadrosaurid elements, particularly of
juvenile and baby-sized individuals, is based on comparisons with
Hypacrosaurus stebingeri (Horner and Currie, 1994), Maiasaura
peeblesorum (Horner, 1999), and hadrosauridae indet. from the
Horseshoe Canyon (Ryan et al., 1998) and Dinosaur Park formations
(Tanke and Brett-Surman, 2001) of Alberta, and the Fruitland
Formation (Hall, 1993) of New Mexico. Identification and terminology
of the theropod teeth follow Currie et al. (1990),Baszio (1997a), and
Fanti and Therrien (2007).
3.1. Institutional abbreviation
UALVP, University of Alberta Laboratory of Vertebrate Palaeontology,
Edmonton, Alberta, Canada; TMP, Royal Tyrrell Museum of Palaeontol-
ogy, Drumheller, Alberta, Canada.
Fig. 2. Composite stratigraphic section showing the stratigraphic occurrence of Sites A, B, and C as well as the only dated bentonite from the Kleskun Hill locality. Paleocurrent
directions are represented by rose diagrams close to the beds in which the sedimentary structures were observed.
39F. Fanti, T. Miyashita / Palaeogeography, Palaeoclimatology, Palaeoecology 275 (2009) 37–53

3.2. Other abbreviations
BW, tooth basal width; FABL, fore–aft basal length; TCH, tooth
crown height.
4. Sedimentology
Fluvial deposits exposed at the Kleskun Hill represent a medium-
to-high sinuosity channel system within an alluvial plain and
comprise predominantly interbedded mudstone, siltstone, and
minor sandstone. Sedimentological analyses and facies associations
indicate that, overall, the depositional environment was a low-energy,
swampy alluvial area where a series of light coloured bentonitic
sandstones, organic rich-mudstones, coal seams, thin bentonite, and
ironstone beds accumulated under medium to high accommodation
conditions (Fig. 2).
The presence of three discrete and laterally persistent coal beds
permitted to reliably refer different outcrops and fossiliferous sites to
a composite stratigraphic column; significant variations in geome-
tries, lithology, and palaeocurrents within observed inclined hetero-
litic strata (IHS, sensu Thomas et al., 1987) allowed to identify two
overlapping intervals in the exposed strata.
The lower interval (zone 1) is characterized by b1–4 metre thick
fining-upward sequences of silt and mud with minor fine grained
sandstone. Trenches through twelve outcrops show dips of bedding
planes between 20° and 35° suggesting a significant component
of lateral accretion. IHS consist of brownish silt and grey, organic
rich mud forming a graded rhythms within individual inclined units
(Fig. 3A). Vertical accretion on top of IHS is documented by oxbowand
back swamp deposits that include brown and green mudstones
interbedded with wet and immature paleosols, bentonitic horizons,
and thin ironstone lenses (Fig. 3B). Gypsy, sideritic, and carbonaceous
concretions and nodules are recurrently associated with light coloured
sediments of this interval. Lastly, channel fill deposits of zone 1 are
capped by reddish peat horizons, 40 cm thick on average, that
gradually change into tabular coal seams up to a metre thick that deep
gently westward with an angle of 10–11°. Such layers have been traced
at the Kleskun Hill Park over an area of approximately 40 km
2
as well
as in several well logs in the Grande Prairie region, thus supporting the
presence of high-water table and swampy environments over a vast
area. Vertebrate remains described herein were primarily recovered
from fine, organic-rich deposits of zone 1.
The overlying interval (zone 2) consists of up-to 7 metre thick
fining-upward sequences of low angle (5–10°) interbedded sand and
silt. Sporadic pebbles and ironstone nodules occur at the base of
inclined beds (Fig. 3C). Sandstones are light grey in colour, fine
grained, and characterized by a pervasive carbonate cement. Mud
component is nearly absent and restricted to discontinuous lenses.
Fining-upward deposits are often cut by channel-base fine sands
and locally topped by 10–15 cm thick, discontinuous ironstone lay-
ers. In spite the fact that silicified plant and wood remains are
ubiquitous within this interval, zone 2 lacks organic-rich beds, paleo-
sols, as well as peat and coal, suggesting higher drainage conditions
and minor distance from the active channel belt. To date, few and
poorly preserved vertebrate remains have been recovered from this
interval.
The transition from zone 1 to zone 2 is interpreted as a shift from
highly vegetated, swampy and bog-rich environments characterized
by permanent high-water table conditions to the active channel belt
within the alluvial plain. Differences in lithology and clinoform
geometries observed in zones 1 and 2 may also reflect local variations
in size, sinuosity, and pattern of the channel system and consequent
extension of oxbows and back swamp areas. Palaeocurrent measure-
ments (n=25) taken either parallel or perpendicular to that of
clinoforms from both zones 1 and 2 indicate predominant flows
direction toward the northeast (average on 25 measurements N60°E).
However, a certain degree of variability observed is consistent with a
high-sinuosity fluvial system.
Fig. 3. Exposures of the Campanian fluvial deposits of the Wapiti Formation at the Kleskun Hill Park. A, interbedded light coloured silt and organic-rich mudstones (IHS) capped by a
couplet of tabular reddish peat and coal. B, heavily rooted paleosol formed by interbedded dark grey, organic-rich mudstone and whitish, carbonaceous mudstone overlying a 45 cm
thick coal bed. C, the transition from muddy, organic-rich deposits of zone 1 to overlying silty and sandy channel facies of zone 2 (see text for discussion). D, site A. E, site B. F, site C
(see also Fig. 1). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)
40 F. Fanti, T. Miyashita / Palaeogeography, Palaeoclimatology, Palaeoecology 275 (2009) 37–53

Lastly, the top of the exposed interval at the Kleskun Hill is marked
by a 35 cm thick, laminated, carbonate cemented sandstone that also
denotes the present day prairie level morphology. The subaerial,
strongly erosive nature of its basal contact and the coarser grain size of
the sandstone suggest a crevasse splay origin.
5. Palaeopedology
The presence in the study area of distinctive paleosol related
features provides useful information on soil acidity, precipitations,
and water saturation. Pedotype are associated with specific environ-
ments (Fastovsky and McSweeney, 1987; Retallack et al., 1987;
Retallack, 1994, 2001; Schaetzl and Anderson, 2005) and therefore
may provide a reliable way to investigate local environmental and
climatic conditions preserved within the Kleskun Hill deposits.
Pedotype features observed in the study area include well developed
peat deposits, tabular coal seams, ironstone layers, bentonitic heavily
rooted soils, as well as sideritic, calcitic, and gypsic concretions, and
discontinuous siliceous/tuffaceous horizons.
The presence of several decimetre-thick peat levels within zone 1
indicate a water-saturated environment with persistent high moisture
content, such as bog or fen, characterized by acidic conditions. Peat
results from decomposition of significant amount of organic matter
(usually plant remains) that accumulated under swamp, marsh, or
other kinds of vegetation that can tolerate permanent waterlogged
ground (Histosol,Retallack, 2001). The presence of extensive vegeta-
tion and still water is also indicated by abundant plant remains within
the peat layers (including coalified roots, seeds, leaves, and amber),
overlaying well developed coal seams, and laminar calcitic concre-
tions generated by flocculation processes. Tabular, decimetre-thick
ironstone deposits, also support the presence of widespread bogs in
the area and significant amounts of percolating water under tropical
or sub-tropical climatic regimes. Acid soil conditions are also
responsible for higher Fe concentrations and therefore for the
formation of observed sideridic nodules and ironstone layers. The
presence of siliceous nodules and tuffaceous concretions within the
uppermost portion of channel fill deposits of zone 1, probably reflects
intense lisciviation processes of volcanic ash soils over a period of
weathering under humid climatic conditions (Podzols,Schaetzl and
Anderson, 2005). In support of this hypothesis, similar processes
observed today are typical of environments characterized by very
humid to temperate moist climate, high water table, and associated
with coniferous or mixed forests. However, such processes result in
light grey coloured horizons deep in the ground, whereas at the
Kleskun Hill chert accumulated primarily in concretions that
represent casts of roots and cavities. Large, bidimensional (3–5 cm)
gypsum crystals and concretions are fairly common within the silty
intervals of zones 1 and 2; their abundance suggests paleosol
development with possible wet–dry cycles, strongly connected with
periods of prolonged subaerial exposure (Retallack, 2001; Schaetzl
and Anderson, 2005). However, such crystals are most likely related to
digenetic processes influenced by sulphur-rich percolating water and
by intense bacterial activity within organic rich bogs (Phillips and
Bustin, 1996), as also documented by high sulfur contents within the
sediments (more than 600 ppm on average).
6. Vertebrate palaeontology
Dinosaur elements represent nearly 87% (n= 225) of the 260
fossils collected from the Kleskun Hill Park and consist predominantly
of hadrosaur and theropod teeth (including Troodon, tyrannosaurids,
Saurornitholestes,Richardoestesia,Paronychodon, dromaeosaurids, and
a bird), and hadrosaur postcranial elements (Fig. 4). The remaining
specimens include elements from fishes, squamates, turtles, ankylo-
saurids, ceratopsids, pachycephalosaurids, and mammals, all char-
acteristic components of Campanian terrestrial assemblages in
western North America (Ryan et al., 1998; Brinkman, 2008; DeMar
and Breithaupt, 2008, and references therein).
6.1. Fish
Three different taxa of fish have been collected from Site B, each
represented by a single type of element: an esocoid dentary (TMP
2004.23.7), three holostean A scales (TMP 2004.23.6), and a holostean
B scale (TMP 2004.23.8; Fig. 8). The esocoid dentary has C-shaped
tooth bases as in those collected from the Campanian of southern
Alberta, and is most similar to Oldmanesox sp. in that there are only
one or two rows of teeth (Brinkman, 1990; Wilson et al., 1992). As in
Oldmanesox, the tooth row is single in the posterior part of the dentary
(Fig. 8A–D). The scales of holostean A are identified on the basis of a
peg-and-socket joint, thin enamel cover, and absence of tab-like ex-
tension (Brinkman, 1990)(Fig. 8E–G). The holostean B scale (Fig. 8H)
differs from those of a holostean A in that it has multiple tubercles
on the enamelled surface (Brinkman, 1990). The fish elements are
virtually indistinguishable from those described from the Campanian
of southern Alberta (Brinkman, 1990; Wilson et al., 1992; Brinkman
and Neuman, 2002)(Fig. 8A–M).
6.2. Non-dinosaurian reptiles
A possibleturtle carapace fragment was collected from SiteA (Fig. 8),
but the weathering on thesurface precludespossibility of identifying the
element to further taxonomic level.
Squamate remains are relatively abundant and well-preserved in
Site A, consisting of articulated skulls and several isolated cranial and
postcranial elements. Specimens were recovered exclusively from a
discrete bentonitic paleosoil that occurs in the organic-rich deposits of
zone 1. Interestingly, squamate remains from the Cretaceous of North
America are more commonly found in significantly dryer environ-
ments (Gao and Fox, 1991, 1996; Nydam, 2000; Nydam et al., 2007).
These noteworthy squamate materials merit detailed systematic
description elsewhere and are currently under study.
6.3. Theropoda
6.3.1. Troodontidae
The most abundant theropod teeth recovered from Site A are
identified as Troodon for having relatively large, strongly-hooked
denticles, and recurved crowns (Fig. 5A–F). A few specimens have
wear facets (Schubert and Ungar, 2005) and spalled surfaces that
extend from the apexof the teeth. The Troodon teeth from the Kleskun
Hill Park are indistinguishable from other Troodon teeth described
from deposits of Wyoming (Lance Formation), Montana (Judith River
Formation), Alberta (Belly River Group, and Horseshoe Canyon
Formation), and Alaska (Prince Creek Formation) (Russell, 1948;
Brouwers et al., 1987; Currie, 1987; Currie et al., 1990; Fiorillo and
Currie, 1994; Baszio,1997a; Holtz et al.,1998; Ryan et al.,1998; Sankey
et al., 2002; Fiorillo, 2008a; Sankey, 2008b). Based on variation in
dental morphology along the dental series in Troodon (Currie, 1987),
the Kleskun Hill specimens encompass the entire tooth series,
including premaxillary, posterior maxillary, and posterior dentary
teeth. Troodon has been reported from other stratigraphic levels and
fossil localities of the Wapiti Formation in the Grande Prairie region
(Tanke, 2004; Currie et al., 2008) supporting a wide distribution of
this taxon; however, the relative abundance of Troodon teeth is
remarkably high at the Kleskun Hill microsites (11.9%).
6.3.2. Dromaeosauridae
Three teeth are identified as Saurornitholestes sp. (Fig. 5H–L) based
on elongate and hooked shaped denticles, size differences between
anterior and posterior serrations and strong labio-lingual compres-
sion (Currie et al., 1990; Baszio, 1997a; Sankey et al., 2002).
41F. Fanti, T. Miyashita / Palaeogeography, Palaeoclimatology, Palaeoecology 275 (2009) 37–53

6.3.3. Dromaeosauridae indet
Although only the anterior carina has been preserved, UALVP
50640.01 is distinctive in that denticles vary greatly in size along the
crown, from 2.5 to 5 per millimetre, curve slightly distally toward the
tip of the tooth, and have sharp ridges of enamel along the midline
(Fig. 5G). Blood grooves (sensu Fanti and Therrien, 2007,Fig. 3B) are
Fig. 5. Miscellaneous theropod and bird teeth from Kleskun Hill Park, Grande Prairie, Alberta. A–B, Troodon posterior premaxillary or anterior maxillary tooth (TMP 2004.23.3):
A, detail of posterior denticles; B, entire specimen (lingual and labial). C, Troodon posterior dentary tooth, UALVP 48750 (labial and lingual); D–E, Troodon premaxillary tooth, UALVP
48755 (labial): D, detail of denticles; C —entire specimen. F, Troodon, UALVP 48753, anterior maxillary tooth (lingual and labial). G, Dromaeosauridae indet. tooth, detail of the
posterior carina, UALVP 50640.01. H–L, Saurornitholestes tooth, TMP 2004.23.4: H, detail of posterior denticles; I, entire specimen (labial and lingual); L, detail of anterior denticles.
M–O, Richardoestesia tooth, TMP 2004.93.3: M, detail of posterior denticles; N, entire specimen; O, detail of anterior denticles. P, Paronychodon tooth, UALVP 48815 (labial and
lingual). Q, Tyrannosauroid tooth, UALVP 50641.01 (anterior). R, Tyrannosauroid tooth, UALVP 48760, detail of denticles. S, Tyrannosauroid premaxillary tooth, UALVP 50641.02
(lingual). T, Tyrannosauroid tooth, (?dentary), UALVP 48773 (labial and lingual). U–Z, bird tooth, TMP 2004.93.4: U, basal section; V–Z, entire specimen (lingual and labial).
Fig. 4. Microvertebrate specimens (n=260) from the Kleskun Hill locality, Wapiti Formation. Dinosaur elements comprise the 86.5% of recovered elements (particularly hadrosaurid
and theropod elements), and squamates and fishes are largely represented.
42 F. Fanti, T. Miyashita / Palaeogeography, Palaeoclimatology, Palaeoecology 275 (2009) 37–53

43F. Fanti, T. Miyashita / Palaeogeography, Palaeoclimatology, Palaeoecology 275 (2009) 37–53

absent or restricted to the base of the denticles, being shallow and
poorly defined. Both denticles and blood grooves are oriented
perpendicular to the longitudinal axis of the tooth. Therefore,
specimen UALVP 50640.01 is assigned the taxonomic status Dro-
maeosauridae indet.
6.3.4. Family unknown
One incomplete tooth (UALVP 48815) is identified as Paronychodon
sp. (Fig. 5P). This specimen is the first unequivocal record of this taxon
from the Wapiti Formation and is the most northern occurrence to
date. The non-serrated tooth has three characteristic longitudinal
ridges on both lingual and labial sides, and an elongated and slightly
apically curved overall shape (FABL, 2.3 mm; BW, 1.1 mm; TCH,
3.9 mm). The flattened and ridged lingual surface becomes broader
anteriorly toward the base of the tooth.
6.3.5. Tyrannosauridae
Fragments of tyrannosaurid teeth are commonly encountered in all
the Kleskun Hill microvertebrate fossil sites as well as in other fossil
sites in the Grande Prairie area. Denticles are wider labially-lingually
than they are long proximodistally and occur 2–2.5 per millimetre
in the posterior carina and 3–3.5 per millimetre in the anterior one
(Fig. 5Q–S). Blood grooves are small and restricted to the base of
denticles. The most complete tooth (UALVP 48773.2007.6) lacks the
basal-most portion and would have exceeded 10 cm in height when
complete (FABL, 34.5 mm; BW, 30 mm; TCH 95 mm). The number of
denticles per millimetre on the anterior and posterior carinae is 2.5
and 2 respectively. In cross section, the tooth is compressed labio-
lingually. It is similar in size and overall morphological characteristics
to those of tyrannosaurids from the Campanian and Maastrichtian
successions of southern Alberta (Fig. 5T).
6.3.6. Theropoda incertae sedis
A single small theropod tooth from the Site B (TMP 2004.93.3) is
assigned to Richardoestesia gilmorei based on the minute denticles on
the anterior carina and the small denticles on the posterior carina
(Currie et al., 1990; Sankey et al., 2002). The tooth lacks the top of the
crown, but the morphology is identical to those found in the
Campanian deposits of southern Alberta in that it is labio-lingually
compressed with a moderately recurved posterior carina, and it is
relatively small compared to other theropod teeth (Fig. 5M–O).
6.4. Bird
A small, unserrated tooth from the Site B (TMP 2004.93.4) is
identified as that of a bird (Fig. 5U–Z). The tooth is short and lacks
denticles, but its posterior margin is blade-like and shows anincipient
carina. The crown is more compressed labio-lingually than in other
theropod teeth from the same locality. It has a few wrinkles on the
lingual surface parallel to the anterior margin of the tooth. It also differs
from the bird teeth from the Belly River Group (Campanian), southern
Alberta described by Sankey et al. (2002) in that the tooth crown
recurves slightly posteriorly (Hope, 2002). However, the crown tip is
still anterior to the posterior margin of the tooth and the crown base
expands anteroposteriorly as in other bird teeth (Sankey et al., 2002).
6.5. Hadrosauridae
More than half of hadrosaurid elements collected at the Kleskun
Hill consist of adult-sized teeth and teeth fragments, tendons, and
poorly preserved postcranial bones. Teeth are worn on the occlusal
surfaces and have a medial carina on the lingual surface.
Other hadrosaurid specimens include three dentary fragments,
well preserved teeth, dorsal and caudal centra, a partially preserved
pedal phalanx, and an ungual and are all referable to hatchling- to
nestling-sized hadrosaurs (Fig. 6). The dentary fragments (Fig. 6L–Q)
have pitted surfaces on both sides, and the alveoli (4–5 mm in width)
correspond with size of the teeth. The better preserved baby tooth
(UALVP 48748) has a crown height and width of 7 and 4.5 mm
respectively, which roughly compares to the largest tooth of an
embryonic Hypacrosaurus stebingeri (4 mm in width; Horner and
Currie, 1994). As in other juvenile hadrosaurid teeth, the tooth is
compressed labio-lingually relatively to those of a typical hadrosaurid
adult. It has the crown–root angle greater than 145° as in
lambeosaurines (Horner et al., 2004). The tooth has a straight median
carina as in hadrosaurines and some lambeosaurines, and an
accessory ridge independent from the median carina on the enameled
side as in some lambeosaurine teeth (Horner et al., 2004). Teeth of
embryonic or hatchling individuals of Hypacrosaurus stebingeri
(Horner and Currie, 1994) and Hadrosauridae indet. (Ryan et al.,
1998) lack the accessory lingual ridge observed in the Kleskun
Hill specimens. Furthermore, the enamel edges have irregular and
tiny denticles (papillae, after Horner, 1992) toward the apex of the
tooth. Other teeth are roughly comparable to UALVP 48748 in size
(Fig. 6A–C).
The baby-sized hadrosaurid vertebrae consist of a single dorsal
centrum (UALVP 48816) and four caudal centra (UALVP 48751.01,
48751.02, 50636.03 and 50636.09) (Fig. 6). UALVP 48816 reaches
10 mm in transverse central width, UALVP 48751.01 is 7 mm wide, and
UALVP 50636.09 is a distal caudal centrum with 4 mm in width, as
wide as the teeth are. All the specimens have smooth sutural surfaces
on the dorsal side for the neural arch. The neural canal is relatively
broad, being about two thirds of the centrum width. As in other
hadrosaurids, immature or mature individuals, the dorsal centrum
(UALVP 48816) is hexagonal when viewed anteriorly or posteriorly,
and bears ventral keels. The caudal centra (UALVP 48751.01 and
48751.02) are vertically low and transversely wide relative to those of
adult hadrosaurids. Ventrally, contact with a haemal arch is not clear.
UALVP 48751.01 retains a notochordal pit which has previously been
observed for baby hadrosaurid vertebrae from the Horseshoe Canyon
Formation (Ryan et al., 1998). The pedal ungual (UALVP 48817; 9 mm
in length) is relatively narrowand elongate compared to those in adult
hadrosaurids, and is less constricted at the base (Fig. 6T–U).
The baby hadrosaurid materials from the Kleskun Hill compare
well with those of Hypacrosaurus stebingeri from the Oldman and Two
Medicine formations (Horner and Currie, 1994) and Hadrosauridae
indet. from the Horseshoe Canyon Formation (Ryan et al., 1998). The
baby-sized hadrosaurid materials are either not worn or with minor
abrasion, whereas wear is evident in the adult hadrosaurid elements.
The simples assumption is to associate the specimens to a single
hadrosaurid taxon. The accessory ridge parallel to the median carina
and the relatively large crown–root angle (Horner et al., 2004) further
suggest that these are from a lambeosaurine hadrosaur.
6.6. Ceratopsidae
Four ceratopsian teeth were recovered from microsites at the
Kleskun Hill Park. Three of them (UALVP 50636.08, 50636.10, and
50636.11) are referred to adult individuals based on size, overall
shape, and denticulate ridge (Fig. 7A). Specimen UALVP 50636.08
Fig. 6. Baby and juvenile hadrosaurid elements from Kleskun Hill Park, Grande Prairie, Alberta. A–C, baby teeth (lingual): A, UALVP 50636.01, B, UALVP 48748, C, UALVP 50636.02.
D, dorsal centrum, UALVP 48816. E, caudal centrum, UALVP 50636.03. F–H, caudal centrum, UALVP 48751.01, in anterior (F), dorsal (G) and ventral (H) views. I, caudal centrum,
UALVP 48751.02 (anterior). J, caudal centrum, UALVP 50636.09 (anterior). L–M, maxillary fragment, UALVP 50636.04 (lingual and lateral). N–O, jaw fragment, UALVP 50636.05
(lingual and lateral). P–Q, jaw fragment, UALVP 50636.06 (lingual and ventral). R–S, UALVP 50636.09. T–U, pedal ungula, UALVP 50636.07 (lateral and anterior). V, distal end of ulna,
UALVP 50636.08. Z, caudal vertebra, UALVP 50637 (anterior).
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45F. Fanti, T. Miyashita / Palaeogeography, Palaeoclimatology, Palaeoecology 275 (2009) 37–53

represents a tooth from ajuvenile. It is significantly smaller than other
ceratopsian teeth from the locality (FABL, 2 mm; TCH, 3 mm) and is
convex in both dorsoventral and mesiodistal views. It contains a sharp,
unserrated central ridge as well as less developed secondary ridges
and denticles (Fig. 7B). Ceratopsian remains are often recovered
within the fluvial deposits of the Wapiti Formation, usually preserved
in large-scale bonebeds. Currently, all identifiable ceratopsian speci-
mens from the formation are referred to two species of Pachyrhino-
saurus (Tanke, 2004; Currie et al., 2007; Fanti and Currie, 2007; Currie
et al., 2008). Therefore the teeth from the Kleskun Hill Park are
tentatively referred to Pachyrhinosaurus sp.
6.7. Ankylosauridae
Two ankylosaurid teeth (UALVP 48747 and TMP 2004.23.9) were
recovered from Sites A and B respectively. The teeth are weathered to
the extent that the enamel surface is almost entirely gone (Fig. 7C).
6.8. Hypsilophodontidae
A pachycephalosaur tooth (TMP 2004.93.1) were collected from
Site B. The base is thickened, and a robust median ridge supports the
spade-shape crown with multiple denticles and ridges (Fig. 7D–G).
Tentatively identified as a hypsilophodont, an ornithischian isolated
tooth from the Site B (TMP 2004.93.5) is heavily worn and weathered.
Even though identification of such an incomplete element is difficult,
the labio-lingually flattened tooth with multiple ridges extending to
the base of the crown is most likely a non-hadrosaurid ornithopod.
Size of the tooth assumes an animal similar in size with Parksosaurus
and immature Thescelosaurus (Fig. 7H–L).
6.9. Mammals
Two isolated mammal teeth were collected from Site B. One is a
multituberculate P
3
(TMP 2004.23.2; Fig. 8S–T). As in Chulsanbataar
and others (Clemens and Kielan-Jaworowska, 1978), the premolar is
plesiomorphic in having two roots. Its posterolingual part is reduced
by anterolingual expansion of the P
4
. The four cusps are largely conical
and weakly ridged on their anterior and posterior slopes long-
itudinally. Of the three cusps on the labial side, the anteriormost is the
smallest and more lingual than the posterior two. A transversely wide,
anteroposteriorly narrow basin sits between the anteriormost labial
cusp and the lingual cusp. The second labial cusp is highest, followed
by the posteriormost labial cusp and then by the lingual cusp. Based
on these characteristics, the premolar most closely resembles that of
Cimolodon, but the specimen lacks the posterior lingual cusp. In
addition, the only lingual cusp is displaced relatively more posteriorly,
the anteriormost labial cusp is the smallest, and the posteriormost
labial cusp is relatively larger and higher than in previously known
species of Cimolodon. The tooth is tentatively assigned here to Cimo-
lodon sp.
The second specimen is a double-rooted right lower molar of a
marsupial, presumably RM
4
(TMP 2004.23.1; Fig. 8U–Z). The molar is
relatively shorter anteroposteriorly than in typical marsupial molars
such as that of Herpeotherium, and characterized by the trigonid twice
as tall as the talonid as in M
4
of Didelphodon coyi (Fox and Naylor,
1986). The roots are approximately 1.5 times deeper than height of the
trigonid. The molar has styler shelves around its anterior and posterior
margins. The metaconid is more anterior than the protoconid, and
reduced in size to the shortest cusp in the trigonid. Both the
protoconid and paraconid are oriented slightly posteriorly than the
Fig. 7. Miscellaneous ornithischian elements from Sites B and C. A, Pachyrhinosaurus sp. tooth, UALVP 48752 (lingual). B, baby ceratopsian tooth, UALVP 50636.10 (lingual).
C, ankylosaurid tooth, UALVP 48747 (labial). D–G, Pachycephalosaurid teeth: D–E, TMP 2004.93.1A (lingual and labial); F–G, TMP 2004.93.1B (lingual and labial). H–L,
hypsilophodont tooth, TMP 2004.23.5 (lateral, labial, and lingual).
46 F. Fanti, T. Miyashita / Palaeogeography, Palaeoclimatology, Palaeoecology 275 (2009) 37–53

metaconid. The triangle formed by the protoconid, metaconid, and
paraconid has an acute angle at the protoconid, comparable to Di-
delphodon sp., more acute than Eodelphis, and wider than D. coyi (Fox
and Naylor, 1986). The talonid basin is slightly narrower transversely
than the trigonid, and approximately as long anteroposteriorly as the
trigonid. The styler cups A, B, and C are nearly equal in size and form
the labial margin of the talonid basin. The styler cusp D is larger, at the
posterolabial corner of the talonid. It has two cristae extending toward
the hypoconid, and also connects to the posterior styler shelf. The
hypoconid is transversely wide, and the prehypoconid crista extends
anterolabially, separating a pocket on the lingual side between the
protoconid and the hypoconid from the talonid basin. Unlike Alpha-
don, the molar is less than twice anteroposteriorly long as wide across
the protoconid (Lillegraven, 1969). Unlike Pediomys, the styler cusps
sit closer to the trigonid, forming an anteroposteriorly limited talonid
basin as in Didelphodon (Lillegraven, 1969; Fox and Naylor, 1986). The
molar morphology most closely resembles that of Didelphodon, and
thus it is tentatively referred to Didelphodon sp. The molar is about
half the size of the previously described Didelphodon molars.
7. Discussion
The vertebrate diversity recovered from the Kleskun Hill sites
indicates that the locality is a multidominant, high diversity microsite
(following the classification and nomenclature proposed by Eberth
et al., 2007). The site originated in a channel/overbank-wetland
palaeoenvironment characterized by wet and humid climatic condi-
tions. The twelve dinosaur taxa identified outnumber other verte-
brates and represent 54.6% of the overall diversity. Hadrosaurid bones
and teeth are 46.9% of all the recovered elements and together with
theropod teeth (35.4%) constitute the bulk of the collection, with eight
taxa represented. Of paramount importance, elements identified as
baby and hatchling individuals represent the 18.9% of all hadrosaurian
material. These well preserved fossils were subject to negligible pre-
burial transportation, strongly supporting the presence of a nesting
ground nearby. In addition, the pattern of distribution of different taxa
appears to be intimately linked to different depositional environments
observed in the Kleskun Hill outcrops. For instance, Site A is
characterized by organic-rich clay and mud, and bentonitic paleosols
deposited under high- and still-water table conditions suggesting
permanent swampy and bogs-like environments. Multidominant
microsites are often interpreted as post-deposition reworked assem-
blages (Brinkman et al., 2007; Eberth et al., 2007; Rogers and Kidwell,
2007). However, sedimentological and palaeontological features
observed at Site A suggest accumulation in low-sedimentation-rate
palaeoenvironments unaffected by relevant hydraulic transportation
or reworking processes (Bown and Kraus, 1981; Eberth et al., 2007).
Thus, in terms of depositional system the site is referred to a wetland/
bog/marginal-pond palaeoenvironment.
Using the same classification criteria adopted for Site A, Sites B
and C can be referred to high-diversity multidominant and mono-
dominant microsites respectively (Fig. 9). Site B is dominated by fish
remains (37.9%), with frequent theropod (13.8%) and hadrosaur
(13.8%) elements, whereas Site C is characterized by abundant tyran-
nosaurs teeth (78.9%). Depositional setting distinguishes Sites B and
C from Site A. Both Sites B and C occur within sandy, well-drained,
channel-lag and overbank deposits characterized by high-energy and
significant pre-burial reworking and abrasion, as indicated by the
poor preservation of vertebrate remains. In addition, elements col-
lected within this interval are: 1) generally larger than those
recovered at Site A; and 2) mainly come from large-sized animals
(i.e. full grown tyrannosaurs, ceratopsian, and hadrosaurs). Conse-
quently, the taxa represented in those sites are not necessarily
representative of the Kleskun Hill Park area and may include
elements mobilized by hydraulic processes within the active channel
belt of the alluvial plain.
7.1. Possible explanation for abundance of Troodon
Hadrosaurids and small theropods (Troodon,Saurornitholestes,
Paronychodon, and Dromaeosauridae indet.) represent 76.4% of all the
specimens from Site A. Particularly, hatchling- to nestling-sized
hadrosaurids occur at 10.9% (baby hadrosaurids account for 17.4% of
all hadrosaurian elements), and Troodon occupies 16.7%. Ryan et al.
(1998) suggested a non-random association between baby hadro-
saurids and Troodon in a microvertebrate fossil locality in the
Horseshoe Canyon Formation of southern Alberta (latest Campa-
nian–early Maastrichtian), where other dinosaur taxa are uncommon.
Barring the small sample size of Troodon and baby hadrosaurs, their
relative abundance may be congruent with Ryan et al.'s finding and
possibly expands this distribution of the baby hadrosaurid-Troodon
association northwards. Ryan et al. (1998) explained the association
with the hypothesis that Troodon hunted on either young or small
sized dinosaurs, at least as a part of their diet. However, the high
abundance of both baby hadrosaurids and Troodon in Site A alone does
not constitute evidence of the predator–prey association in the
locality. Whether or not feeding on hatchling and young hadrosaurs,
the abundance of small theropods at Site A is probably reflection of
relatively large number of small-bodied predators in the area. The
small and agile carnivores would have been more successful in a
swampy, palustrine, and highly vegetated environment inaccessible to
larger carnivores such as tyrannosaurids.
Beside feeding strategy of Troodon, the genus seems to show
latitudinal gradient in its relative abundance within local theropod
faunas. Troodon is increasingly more common northward, with 6%
occurrence rate in the Judith River Formation of Montana (Currie and
Fiorillo, 1994), 31.2% in the northern section of the Wapiti Formation
(Fanti, 2007; this paper) and 65% in the Prince Creek Formation of
Alaska (Fiorillo and Gangloff, 2000; Fiorillo, 2006). Sankey (2001)
rejected the previous assignment of the theropod teeth to Troodon sp.
from the Aguja Formation of Texas, and suggested that Troodon was a
member of the northern dinosaur assemblages. The unusual abun-
dance of Troodon in the Kleskun Hill locality may not accurately reflect
its real abundance in the region because it may assume local
environmental factors, such as food source, that favoured assembling
Troodon. Another confounding problem is that compared localities are
not necessarily contemporaneous to each other. Although these
caveats suggest that the high Troodon occurrence in the north may
be partly exaggerated, it is plausible that Troodon was more common
in northern regions (Baszio, 1997a,b; Fiorillo and Gangloff, 2000).
8. Faunal comparison
In spite of the taxonomical diversity preserved at the Kleskun Hill,
the limited sample size precludes a detailed and extensive statistic
comparison between the local fauna and fossil association reported
elsewhere in western Canada and the United States. However, the
microvertebrate fossil assemblage at the Kleskun Hill locality
represents 92% of the total vertebrate diversity recovered from the
Wapiti Formation to date. For this reason, specimens described in this
paper allow a preliminary reconstruction of the palaeocommunity in
such an important temporal and geographical context (Fig. 10).
Three fish taxa are recognized from the Kleskun Hill: an esocoid
(Oldmanesox sp.) and holosteans A and B. They are virtually indis-
tinguishable from their counterparts in the Belly River Group (Campa-
nian) of southern Alberta (Brinkman, 1990; Wilson et al., 1992;
Brinkman and Neuman, 2002) and represent the northernmost record
of this association. Holostean A continued to occur into Maastrichtian
deposits in southern Alberta (Horseshoe Canyon and Scollard forma-
tions, Edmonton Group), althoughOldmanesox and holostean B seem to
be absent in the Group (Eberth et al., 2001).
Discovery of squamates and a possible turtle from the Kleskun Hill is
geographically significant because there has been no report of their
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48 F. Fanti, T. Miyashita / Palaeogeography, Palaeoclimatology, Palaeoecology 275 (2009) 37–53

occurrence in the high-latitude and polar Late Cretaceous terrestrial
localities, including the Prince Creek Formation of Alaska (Buffetaut,
2004; Godefroit et al., 2008). Squamates are also interesting stratigra-
phically since their post-Bearpaw to early Maastrichtian record is scarce
in North America (Gao and Fox, 1996). Sternberg (1951) also reported a
teiid squamate jaw from thevicinity of the Kleskun Hill Park. In addition,
Tanke (2004) mentions occurrences of salamander and choristoderan
reptiles. However, such specimenswere not relocated in the collections
and therefore the presence of salamander and choristoderan from the
locality are yet to be confirmed.
All the dinosaur taxa are known from the Campanian–Maastrich-
tian units of southern Alberta (the Belly River Group and Edmonton
Group: Brinkman, 1990; Currie et al., 1990)and,exceptforParony-
chodon,Richardoestesia, and the bird, also from the Prince Creek
Formation of Alaska (Rich et al., 1997; Fiorillo and Gangloff, 2000;
Gangloff et al., 2005). Notably, the occurrence of Paronychodon and
Richardoestesia are the northernmost records of these enigmatic
genera. Fiorillo (2008b) reported unusual teeth of Troodon from the
Prince Creek Formation of Alaska which are twice the size of those
known from southern Alberta and Montana; consequently Fiorillo
suggests that Troodon increases in body size northward, possibly
because of its dominance and competitive edge (e.g., increased orbit
diameter) over other theropods in higher latitudes.
On the contrary, the teeth of Troodon from the Kleskun Hill
Park are comparable in size to those from southern Alberta and
Montana. Therefore, our results are consistent with Fiorillo's hypo-
thesis that Troodon increases in body size as a function of its
dominance over multiple carnivorous niches, but not as a function
of high latitude as predicted by Bergman's rule. Because most taxa
are only identified to the higher taxonomic levels (i.e. Tyran-
nosauridae, Verociraptorinae, Ankylosauridae, Hypsilophodontidae,
Lambeosaurinae, Pachycephalosauridae, Paronychodon,Sauror-
nitholestes,andTroodon), it would not be surprising if the dinosaur
assemblages in Alaska, northern Alberta, and southern Alberta
differed at species or generic level, as predicted by the hypothesis
of dinosaur provincialism in western North America during the
Campanian and Maastrichtian (Lehman, 1987, 1997, 2001; Sampson
and Lowen, 2007). The current data from the Wapiti Formation
support a wide distribution of all dinosaur families and subfamilies
discussed in this paper along the Western Interior during the
Campanian and Maastrichtian, although this does not necessarily
refute the hypothesis of provincialism.
The mammals are tentatively identified as Cimolodon sp. and Di-
delphodon sp. respectively and are the northernmost occurrence for
the genera. In particular, Didelphodon sp. from the Kleskun Hill is most
similar to Didelphodon sp. from the Scabby Bute of southern Alberta
(St. Mary River Formation, Edmonton Group: Fox and Naylor, 1986)
based on the acute triangle formed by the trigonid cusps, suggesting a
close phylogenetic relationship. Discovery of both a multituberculate
and a marsupial is not surprising, because these mammals were
already reported from Alberta (Lillegraven,1969; Fox, 2005) and from
the Prince Creek Formation (Santonian–Maastrichtian) of Alaska
(Clemens and Nelms, 1993; Fiorillo and Gangloff, 2000). Pending
taxonomic assignment of the Alaskan fossils, the Kleskun Hill
specimens are potentially important for mammal palaeobiogeography
during the Late Cretaceous of North America.
According to the most recently compiled dinosaur and other
vertebrate faunal lists (Tanke, 1988; Currie, 1989a; Ryan and Russell,
2001; Weishampel et al., 2004; Tanke, 2004) and in the light of recent
dinosaur discoveries in the Grande Prairie area (Fanti and Currie,
2007; Currie et al., 2008; this paper) more than thirty-five species are
currently known from the Wapiti Formation. Amongst these taxa, the
ceratopsian dinosaur Pachyrhinosaurus lakustai (Currie et al., 2008)is
the only diagnostic vertebrate taxon described from the formation.
Currie et al. (2008) also confirmed that a second ceratopsian bonebed
above the Campanian–Maastrichtian boundary in the Wapiti
Fig. 9. Relative distribution of Kleskun Hill taxa at the three fossiliferous sites. See the text for discussion.
Fig. 8. Miscellaneous elements from Sites A and B. A–D, esocoid dentary, TMP 2004.23.7, in medial (A), lateral (B), dorsal (C), and ventral views (D). E–G, Holostean A scales: E, TMP
2004.93.2 (dorsal and ventral), F, TMP 2004.23.8 (dorsal and ventral), G, TMP 2004.93.5 (dorsal and ventral), H, Holostean B scale, TMP 2004.23.8 (dorsal and ventral). I–J, amiid
centrum UALVP 50638.01, (anterior and dorsal). L–M, amiid centrum UALVP 50638.02 (anterior and dorsal). N, possible turtle shell fragment, UALVP 48754. O–P, Cimolodon sp. tooth
TMP 2004.23.2 (occlusal and labial views). Q–S, Didelphodon sp. tooth, TMP 20 04.23.1 (lingual, labial, and occlusal views).
49F. Fanti, T. Miyashita / Palaeogeography, Palaeoclimatology, Palaeoecology 275 (2009) 37–53

Formation yielded a chelydrid turtle neural plate, a varanid squamate
vertebra, and crocodile scutes.
9. Nesting of hadrosaurids
Hatchling- to nestling-sized hadrosaurid elements from the
Kleskun Hill Park indicate that hadrosaurids nested in the area in
the late Campanian (∼74 My). A high-latitude record of dinosaur
nesting is extremely rare. Recently, Godefroit et al. (20 08) reported
eggshell fragments and juvenile hadrosaur elements from a latest
Cretaceous locality in northern Siberia. In North America, G. Nelms,
in Carpenter (1999) mentions “Edmontosaurus sp. bones”from the
Prince Creek Formation of Ocean Point, Alaska, in the global survey
of baby dinosaur records. However, the supposed Alaskan baby
Edmontosaurus has neither been described nor illustrated since
Nelm's personal communication to Carpenter (1999). In addition,
thepresenceofEdmontosaurus is yet to be confirmed from Alaska
(Bell and Snively, 2008). Therefore, the report on the Alaskan baby
dinosaur material is considered not reliable in this study. The
Kleskun Hill locality is currently the northernmost published record
of a dinosaur nesting ground in North America, pending proper
assessment of the Alaskan material. Fiorillo (2008a) emphasized the
argument in Fiorillo and Gangloff (2001) that the juvenile
hadrosaur materials from the Prince Creek Formation represent
individuals younger than 1 year old. Therefore, it is likely that the
hadrosaurs were year-round residents of the region, inferring that
they also nested in the Arctic.
The hypothesized hadrosaurid nesting site at the Kleskun Hill is
also important in a palaeoecological perspective. Previously, hadro-
saurid nesting sites (referring to localities where eggshells or
embryonic elements have been reported) seemed to preferentially
occur in dry, upland regions (Horner, 1982; Horner and Currie, 1994).
Carpenter (1982, 1992), and Fiorillo (1987, 1989) reported eggshells
and baby or juvenile hadrosaurid specimens from the low-land
settings (the Lance and Hell Creek formations and the Judith River
Formation, respectively). In Alberta, Nadon (1993) noted common
occurrence of eggshells from the anastomosed fluvial deposits of the
St. Mary River Formation, Ryan et al. (1998) described hatchiling- to
nestling-sized hadrosaurid elements from the Horseshoe Canyon
Formation, and Tanke and Brett-Surman (2001) also reported
hatchling- to nestling-sized hadrosaurid elements and eggshells
from the low-land Dinosaur Park Formation of southern Alberta.
Coupled with these previous findings, the Kleskun Hill hadrosaurid
materials provide further evidences that hadrosaurids also nested in
low-land settings. Nadon (1993) proposed that ornithopods prefer-
entially selected wetland habitats as ideal reproductive site where a
soft substrate and flooded conditions would have deterred large
carnivores. The implications are that hadrosaurids seem to have had
various strategies in nesting site selection, and that the fossil record of
nesting sites is taphonomically biased against wet, lowland environ-
ment as weak acidity in groundwater would have generally enhanced
dissolution of eggshells and poorly ossified elements unless buffered.
In addition to hadrosaurids, small ceratopsian elements imply that
ceratopsians either nested in the region or had not migrated over long
distance from the nesting site (Currie, 1989b). Interestingly, post-
cranial elements ascribed to juvenile and subadult hadrosaurs have
been collected from nearly coeval strata cropping out along the Wapiti
River south of Grande Prairie (see also Tanke, 2004). Furthermore,
Currie et al. (2008) report of an almost complete ontogenetic series of
Pachyrhinosaurus lakustai (including juvenile, subadult, and adult
individual) from the densely packed Pipestone Creek bone bed which
has been dated 73.27± 0.25 My. Palaeogegraphic reconstruction for
the Bearpaw time (Dawson et al., 1994) place the Grande Prairie area
in the order of 250–300 km from the shoreline, located approximately
Fig. 10. Reconstruction of the late Campanian vertebrate fauna of the Wapiti Formation near Grande Prairie, Alberta, based on the taxa from the Kleskun Hill locality and correlative
beds discussed in the text. Drawing by Lukas Panzarin.
50 F. Fanti, T. Miyashita / Palaeogeography, Palaeoclimatology, Palaeoecology 275 (2009) 37–53

to the north and to the west of Edmonton. Sedimentological data and
palaeoenvironmental reconstruction presented in this study support
an extensive low-land environment (referring to the low and
relatively level ground of the region, in contrast with adjacent higher
country), genetically related to the maximum transgressive phase of
the Bearpaw Sea.
10. Conclusion
The Kleskun Hill Park vertebrate fauna represents the first high-
diversity multidominant assemblage from the Late Cretaceous of
north western Canada. The fauna is also stratigraphically important
being the only locality that provides a glimpse of a diverse terrestrial
vertebrate fauna in western North America during the Bearpaw Sea
transgressive event about 74 My. At the Kleskun Hill Park, Site A best
represents the vertebrate diversity of the formation because of the
larger sample size. The site is characterized by relative abundance of
Troodon teeth and hatchling- to nestling-sized hadrosaur elements.
The latter suggests the presence of a hadrosaurid nesting ground
in the nearby lowland area within the alluvial plain. In contrast
Sites B and C, both with a smaller sample size, preserve a reworked
assemblage dominated by pre-burial fluvial transportation. The
Kleskun Hill vertebrate fauna preserves many taxa that are common
in Campanian terrestrial vertebrate faunas in southern Alberta. The
locality marks the northernmost distribution of Paronychodon and
Richardoestesia. Additionally, three fish taxa (holosteans A and B, and
an escoid Oldmanesox sp.), squamates, and bird have not been re-
ported from Alaska to date (Fiorillo and Parrish, 2004; Fiorillo et al.,
2007). Multituberculates and marsupials have been reported from the
Prince Creek Formation of Alaska (Clemens and Nelms, 1993), but it is
not clear if the Kleskun Hill Park taxa (Cimolodon sp. and Didelphodon
sp.) are identical to their counterparts in the Campanian of southern
Alberta and Alaska. An impeding task is more sampling at the Kleskun
Hill and assessment of new material from the Alaskan localities which
may further result in testing the hypothesis of dinosaur provinciality
(Lehman, 2001). Although the sample size remains small, the
preliminary account of the vertebrate diversity demonstrates that
the Grande Prairie region promise to be a key area in both
stratigraphic and palaeobiogeographic contexts during the Late
Cretaceous of North America.
Acknowledgements
We thank the Palaeontological Society of Peace, especially Sheldon
Graber, Robert Hunt, Katalin Ormay, Desh Mittra, and their families,
the Grande Prairie Regional College, Philip Currie and Eva Koppelhus
(University of Alberta, Edmonton) for logistic supports in field. Many
thanks are also extended to Nick Ormay and Walter Paszkowski for
their contribution to fieldwork. Don Brinkman (TMP) and Patty Ralrick
did initial sorting and identification of the specimens stored in TMP. F.F.
is also indebted to Dennis Braman, Donald Brinkman, and David Eberth
(TMP) for sharing unpublished data and for stimulating discussions.
Don Brinkman, James Gardner, Brandon Strilisky (TMP) and Philip
Currie (U. of A.) provided access to the collections in their care.
Comments from Julia Sankey (California State University Stanislaus,
Turlock, USA), Finn Surlyk (University of Copenhagen, Denmark), and
an anonymous reviewer greatly improved this manuscript. The first
draft benefited from discussion with Paul McNeil (Grande Prairie
Regional College) and Darren Tanke (TMP). We also acknowledge
Philip Currie, Eva Koppelhus, Rich Palmer (University of Alberta),
Don Henderson (TMP), and Kesia Andressen for their support at
various stages of the project. The specimens were illustrated by Lukas
Panzarin. T.M. extends thanks to students and staffs at Ohwada
Primary School of Hachioji (1992–1998) for continuing encourage-
ments. This work was supported by the University of Bologna, Museum
of Geology and Palaeontology Giovanni Capellini (Bologna, Italy),
Jurassic Foundation, Dinosaur Research Institute, and Grande Prairie
Regional College to F.F., and by personal funds from Junichi and Kanae
Miyashita to T.M.
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