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Sagebrush voles of the monotypic genus
Lemmiscus are an endemic North American
lineage of arvicoline rodents with a modern
distribution that encompasses much of the
Basin and Range, Columbia Plateau, Wyoming
Basin, and northern Great Plains provinces
(Hall 1981). Fossil specimens of Lemmiscus
curtatus are widely reported from Late Pleis-
tocene and Holocene sites (FAUNMAP Work-
ing Group 1994, Bell and Mead 1998, Barnosky
and Bell 2003, Bell and Jass 2004). Fossil
localities span much of the modern geographic
range and include extralimital records just
beyond the margin of the present species
range (e.g., Burns 1991, Jass et al. 2002). The
vast majority of these fossils share a basic den-
tal morphology with the extant populations,
with a lower first molar (m1) characterized by
a posterior loop, 5 or occasionally 6 closed tri-
angles, and a simple anterior cap (Fig. 1). The
first and second triangles of the m1 of L. cur-
tatus are of approximately equal size, readily
distinguishing these molars from those of
species of Microtus, which have a smaller sec-
ond triangle and are often found in close geo-
graphic association with L. curtatus in both
Western North American Naturalist 79(2), © 2019, pp. 219–232
Dental variation in a collection of Lemmiscus curtatus
from the northern plains of southern Saskatchewan:
implications for morphological evolution
CHRISTOPHER J. BELL1,3, CHRISTOPHER N. JASS2,3, AND ROBERT W. BURROUGHS4,5,*
1Jackson School of Geosciences, The University of Texas at Austin, Austin, TX 78712
2Royal Alberta Museum, Edmonton, Alberta T5J 0G2, Canada
3Jackson Museum of Earth History, The University of Texas at Austin, Austin, TX 78712
4Committee on Evolutionary Biology, The University of Chicago, Chicago, IL 60637
5Integrative Research Center, Field Museum of Natural History, Chicago, IL 60605
ABSTRACT.—We provide the first documentation of morphological variation in the lower first molar (m1) of Lemmiscus
curtatus from southern Canada. A total of 370 specimens were obtained from owl pellets taken from 4 localities in southern
Saskatchewan. The 4 most common morphotypes are, in order of descending relative abundance, molars with 5 closed
triangles and a well-developed but widely open sixth triangle, molars with 5 closed triangles and a sixth triangle that is
pinched at the confluence of the anterior cap, molars with 5 closed triangles and incipient closure of the sixth triangle
from the anterior cap, and specimens with 6 closed triangles. As is true of other modern populations of L. curtatus, the
samples from Saskatchewan include no morphotypes with only 4 closed triangles. This collection is notable for the rela-
tively high proportion of specimens with pinched, incipient, or full closure of a sixth triangle on the m1, and it also
highlights the complex dynamics of dental evolution in arvicoline rodents.
RESUMEN.—Documentamos por primera vez la variación morfológica del primer molar inferior (m1) de Lemmiscus
curtatus procedente del sur de Canadá. Un total de 370 ejemplares fueron obtenidos de egagrópilas de búho proce-
dentes de cuatro localidades del sur de Saskatchewan. Los cuatro morfotipos más comunes en las muestras son, en
orden descendente de abundancia relativa, molares con cinco triángulos cerrados y un sexto triangulo bien desarrollado,
pero ampliamente abierto, molares con cinco triángulos cerrados y un sexto triangulo que presenta una constricción
a medida que se acerca a la confluencia con la porción anterior del diente, molares con cinco triángulos cerrados y un
sexto triangulo incipientemente cerrado, y molares con seis triángulos cerrados. Al igual que otras poblaciones actuales
de L. curtatus, las muestras de Saskatchewan no incluyen morfotipos que solamente tienen cuatro triángulos cerrados.
Esta colección de molares destaca por la proporción relativamente alta de ejemplares m1 que presentan un sexto triangulo
constreñido, incipientemente cerrado y cerrado y denota la dinámica compleja de la evolución dental en los roedores
arvicolinos.
*Corresponding author: rburroughs@uchicago.edu
219
RWB orcid.org/0000-0003-4384-3430
present-day and paleontological contexts. Older
fossil occurrences of Lemmiscus include many
specimens with an m1 morphology not encoun-
tered in the extant biota; these specimens have
only 4 closed triangles, with a well-developed
fifth triangle that is confluent with the anterior
cap (Fig. 1A). These older fossil records are from
San Antonio Mountain (SAM) Cave, New Mex-
ico (Rogers et al. 2000); Porcupine Cave, Col-
orado (Bell et al. 2004); Cathedral Cave, Nevada
(Jass and Bell 2011); and the Kennewick Road
Cut in Washington (Rensberger et al. 1984,
Rensberger and Barnosky 1993). The oldest of
these occurrences are from SAM Cave, with an
estimated age of approximately 840,000 years
(Rogers et al. 2000), and the lower stratigraphic
levels of the Pit sequence of Porcupine Cave,
Colorado, with an estimated age range between
800,000 and one million years old (Bell and
Barnosky 2000, Barnosky and Bell 2004). The
youngest of the older sites where 4-triangle
morphotypes are common is Cathedral Cave,
with a maximum age between 146.02 +
–2.584
and 153.7 +
–6.4 ka (Jass and Bell 2011).
220 WESTERN NORTH AMERICAN NATURALIST (2019), VOL. 79 NO. 2, PAGES 219–232
Fig. 1. Extinct (A) and extant (B–G) morphotypes of the m1 of Lemmiscus curtatus.A, L. curtatus with “typical”
4-closed-triangle morphotype (SNK-CNJ8); B, L. curtatus with 5 closed triangles (P17.13.39); C, L. curtatus with 5 closed
triangles (P17.13.103); D, L. curtatus with 5 closed triangles and a T6 that is pinched from the anterior cap (P17.13.183);
E, L. curtatus with 5 closed triangles and a T6 that exhibits incipient closure from the anterior cap (P17.13.136); F, L. cur-
tatus with 6 closed triangles (P17.13.210); G, L. curtatus with 4 closed triangles and confluent T5/T6 that together
exhibit incipient closure from the anterior cap (P17.13.370). T = Triangle. Scale bar = 1 mm. SNK-CNJ8 is a temporary
laboratory number assigned by CNJ. The specimen is presented here to illustrate Lemmiscus with 4 closed triangles.
Four-triangle morphotypes from radioiso-
topically dated Late Pleistocene deposits were
first reported from Snake Creek Burial Cave,
Nevada (Bell and Mead 1998), and subse-
quently from Pleistocene and early Holocene
sediments in Kokoweef Cave and Antelope
Cave, California (Bell and Jass 2004). The
absence of 4-triangle morphotypes in the
extant populations suggests that the “extinc-
tion” of the morphotype occurred within the
last 9000 years. The long fossil record of the
species presents an intriguing perspective on
dental evolution, suggesting a polymorphic
condition of mixed 4- and 5-triangle morpho-
types within early populations that then per-
sisted for over 800,000 years (Barnosky and
Bell 2003), with the 4-triangle morphotype
disappearing prior to the sampling of modern
populations. The pattern is complemented by
what appears to be increasing relative abun-
dance of 6-triangle morphotypes from the
Late Pleistocene through the modern (Rens-
berger et al. 1984, Barnosky and Bell 2003,
Bell and Jass 2004). The possibility that cli-
matic change, particularly warming, may be
at least partly responsible for initiating evolu-
tionary change in this dental pattern was
explored by Barnosky and Bell (2003).
Detailed and meticulously documented pat-
terns of variation from within extant popula-
tions are essential if we are to explore and
understand fully the driving mechanisms that
shaped tooth morphology across the spatio -
temporal distribution of L. curtatus. Detailed
data on dental variation are essential for docu-
menting the morphological “space” occupied
by various populations and for facilitating the
reliable identification and taxonomic treat-
ment of fossil specimens. This is especially
true for monotypic extant lineages like Lem-
miscus that have a rich fossil record and dis-
play shifting morphological characteristics
through time.
The northernmost extant populations of
L. curtatus extend into southern Alberta and
Saskatchewan (Hall 1981; Fig. 2), and we
recently obtained a reasonably large sample of
teeth and jaws of L. curtatus from owl pellets
collected in southern Saskatchewan, which is
near the extreme northeastern distribution of
the species. Patterns of dental morphology are
not well documented for these populations;
only 3 specimens from southern Canada (MVZ
54471–54473) were included as part of the
most robust previous analysis of dental varia-
tion in Lemmiscus (Barnosky and Bell 2003).
Here, we document the morphological pattern
of the m1s from that sample. We also discuss
the significance of the collection for our under -
standing of the spatial distribution of morpho-
types at higher latitudes, and for broadening
the contextual fabric through which hypothe-
ses of dental evolution are shaped.
METHODS
We examined 370 m1s extracted from owl
pellets collected from 4 localities in south-
western Saskatchewan (Fig. 2, Table 1). The
pellets from all localities were derived from
roosts of Great-horned Owls (Bubo virgini-
anus) in association with abandoned buildings,
and in one instance an owl was present at the
roost (T. Schowalter personal communication
2017). The pellet assemblages from each local-
ity are likely time-averaged to some degree,
but given that pellets will break down even in
protected environments (e.g., an abandoned
building), we infer that the pellets represent a
modern assemblage, reflective of populations
of L. curtatus occurring near the localities
today. All specimens reported here are housed
in the Quaternary Palaeontology collection at
the Royal Alberta Museum in Edmonton under
specimen numbers P17.13.1–P17.13.370.
We examined all lower first molars under
binocular microscope and scored each as
belonging to 1 of 5 morphotypes. The morpho-
types correspond to those used by Barnosky
and Bell (2003) and allowed us to capture data
relevant for exploring transitional morphologi-
cal conditions between morphotypes with 5
and 6 closed triangles. A triangle was consid-
ered open if the dentine field between it and
the next anterior triangle was more than 3
enamel-band widths across. We scored a speci-
men as having a “pinched” condition if the
dentine field between triangles was more than
2, but less than 3 enamel-band widths across.
We scored a specimen as having “incipient
closure” if the dentine field was between 1 and
2 enamel-band widths across. A triangle was
scored as closed if the dentine field was less
than 1 enamel-band width across. The 4 most
common morphotypes are 5T (= 5 closed
triangles), 5T with T6 pinched (= a specimen
with 5 closed triangles and a pinched con -
dition between the sixth triangle and the
BELL ET AL.♦TOOTH MORPHOLOGY OF LEMMISCUS FROM SASKATCHEWAN 221
dentine field of the anterior cap), 5T with
incipient closure of T6 (= 5 closed triangles,
with incipient closure between the sixth trian-
gle and the anterior cap), and 6T (= 6 closed
triangles). A fifth morphotpye was represented
by a single unique specimen (P17.13.370)
described below. All morphotypes are illus-
trated and labeled in Fig. 1. We compiled
summary statistics for the morphotypes from
each locality, based on both number of identi-
fied specimens (NISP) and minimum number
of individuals (MNI). Calculations of relative
abundance based on MNI assume that the
lower dentition retains the same tooth mor-
phology in both sides of the jaw. If the m1s of
an individual had distinct morphologies (i.e., if
there was left-right asymmetry), our calcula-
tion of MNI presented below may overesti-
mate the number of individuals represented in
the sample and may be impacting our calcula-
tions of relative abundance based on MNI. A
complete list of specimen numbers and mor-
photype scores is provided in Appendix 1.
Previous work (e.g., Burroughs et al. 2015)
quantifying shape variation as a reflection of
ontogeny did not identify significant occlusal
pattern shifts in L. curtatus that are a result of
ontogenetic wear. Furthermore, comparisons
of males and females by author RWB indicate
that no substantial sexual dimorphism occurs
within the species. As a result, we conclude
222 WESTERN NORTH AMERICAN NATURALIST (2019), VOL. 79 NO. 2, PAGES 219–232
Fig. 2. Map of collecting localities in context of the fossil and extant distributions of L emmiscus curtatus. Shaded area
shows an approximation of the extant distribution of L. curtatus in North America (following Hall 1981). Dashed ellipse
shows an approximation of the fossil distribution of L. curtatus across the Quaternary. Inset: Collecting localities for owl
pellet remains of L. curtatus reported here. Numbers correspond to localities as described in the text and in Table 1
(e.g., 1 = Locality 1).
TABLE 1. Summary of geographic locations and associ-
ated sample size (n) for the m1s of Lemmiscus curtatus.
Locality Latitude Longitude n
1 49.20370 −107.82745 221
2 49.08703 −108.69135 34
3 49.18177 −109.28230 35
4 49.19337 −108.13618 79
that neither ontogeny nor sexual dimorphism
are contributing significantly to patterns of vari-
ation in this or other samples of L. curtatus.
RESULTS
Table 2 and Fig. 3 provide summary
descriptive statistics of the morphotypes pre-
served in the sample (n= 369). One specimen
that we report here (P17.13.370) was excluded
from the summary statistics because it repre-
sents a unique morphotype, having 4 closed
triangles and confluent T5/T6 that exhibits
incipient closure from the anterior cap (Fig.
1G). This morphology was noted in low num-
bers (n= 8) in the fossil assemblage at
Kokoweef Cave (Bell and Jass 2004), and find-
ing it in the modern biota was unexpected.
Although treated as a 4-triangle form previ-
ously (Bell and Jass 2004), the morphology is
not comparable to most fossil specimens
described as having a 4-triangle morphotype
because the T6 is strongly developed and
nearly closed from the anterior cap. In the
sense of previous evolutionary hypotheses,
under which 4-triangle forms give way to
modern populations characterized by 5 or 6
closed triangles, we now consider these speci-
mens to be anomalous morphologies of those
5- or 6-triangle forms. Therefore, no 4-triangle
forms comparable to previously described fos-
sil populations are present in our sample, as
would be predicted given our understanding
of the distribution of that morphology through
time (Bell and Jass 2004). Five-triangle forms
are the most common morphotype, followed
by intermediate forms (i.e., 5-triangles with
either a pinched T6 or a T6 with incipient clo-
sure from the cap). Six-triangle forms are less
abundant but occur in each of the 4 sampled
localities, with a relative abundance between
approximately 6% and 10%.
DISCUSSION
The recovery of a large sample of m1s
exhibiting considerable variation in morphol-
ogy is reflective of the morphological variation
occurring in extant populations of L. curtatus
in portions of southwestern Saskatchewan.
Remains from owl pellets are good proxies for
understanding the richness and diversity of
local environments (e.g., Barnosky 1994, Terry
2008, 2010, Heisler et al. 2013, 2016), and we
infer that the variation observed in our sam-
ples represents a proxy for the distribution of
morphotypes within populations of L. curtatus
in southern Saskatchewan. The remains come
from sheltered environments in or near aban-
doned buildings, indicating that they were
BELL ET AL.♦TOOTH MORPHOLOGY OF LEMMISCUS FROM SASKATCHEWAN 223
TABLE 2. Summary descriptive statistics for tooth morphotypes of Lemmiscus curtatus from Saskatchewan, Canada.
Morphology Right (n) Left (n) NISP R.A. (NISP) MNI R.A. (MNI)
Locality 1
5T 54 51 105 47.5 54 47.4
5T, T6 pinched 32 33 65 29.4 33 28.9
5T, T6 incipient closure 18 16 34 15.4 18 15.8
6T 8 9 17 7.7 9 7.9
TOTAL 112 109 221 100 114 100
Locality 2
5T 7 5 12 35.3 7 35
5T, T6 pinched 7 6 13 38.2 7 35
5T, T6 incipient closure 4 3 7 20.6 4 20
6T 0 2 2 5.9 2 10
TOTAL 18 16 34 100 20 100
Locality 3
5T 10 15 25 71.4 15 65.2
5T, T6 pinched 4 1 5 14.3 4 17.4
5T, T6 incipient closure 2 1 3 8.6 2 8.7
6T 0 2 2 5.7 2 8.7
TOTAL 16 19 35 100 23 100
Locality 4
5T 21 22 43 54.4 22 52.4
5T, T6 pinched 14 10 24 30.4 14 33.3
5T, T6 incipient closure 3 3 6 7.6 3 7.1
6T 3 3 6 7.6 3 7.1
TOTAL 41 38 79 100 42 99.9
deposited within a relatively recent timeframe.
Owl pellets are subject to breakdown from a
number of weathering processes (e.g., tram-
pling, decay, and insect activity; Andrews
1990), but in the absence of mechanical break-
down we infer that the remains are not signifi-
cantly time-averaged, certainly not to the
degree that a fossil deposit would be.
One of the more striking features of the
collection of molars from Saskatchewan is
the high proportion of specimens with some
degree of expression of a sixth triangle. Previ-
ous evaluation of a large sample of modern
L. curtatus from across the present-day distri-
bution indicated that approximately 75% of
individuals had a 5-triangle morphotype, with
the remaining 25% showing some expression
of the sixth triangle (Barnosky and Bell 2003).
In our samples, percentages of specimens
with some expression of a sixth triangle (i.e.,
specimens with a sixth triangle that exhibits
pinching, incipient closure, or complete clo-
sure) were 52.5% (Locality 1), 64.7% (Locality
2), 28.6% (Locality 3), and 55.6% (Locality 4).
Therefore, these collections represent popula-
tions with surprisingly complex molars.
Our data do not directly address the
hypothesis that warming temperatures may
have triggered an evolutionary response toward
increased molar complexity in L. curtatus dur-
ing the middle Pleistocene (Barnosky and Bell
2003). However, our data are especially intrigu-
ing because the collections were taken near
the northeastern periphery of the geographic
range for the species, are at relatively high lati-
tude, and are from relatively cold climatic
conditions. We find it interesting that such
complexity characterizes populations living at
relatively cooler latitudes than populations
that are characterized by 5-triangle morpho-
types farther to the south (Barnosky and Bell
2003). This suggests that although warming
might have initiated genetic or developmental
mechanisms leading to increased complexity,
warmer temperatures may be insufficient to
explain the spatial distribution of populations
with high relative abundance of complex mor-
photypes in the extant biota. We now know
that populations in northern Nevada (Bell and
Jass 2004) and southern Saskatchewan (this
paper) show such complexity. Evaluation of
additional samples is necessary to determine
the full measure of populations that are char-
acterized by more complex m1s (i.e., relatively
high abundance of morphotypes with some
expression of a sixth triangle). Other popula-
tions from across the range of the species are
not presently reported well enough to permit
detailed reconstruction of relative abundance
of various morphotypes (raw data were not
reported by Barnosky and Bell 2003).
Lemmiscus curtatus was included in only
a single phylogenetic analysis of arvicolines
(Robovský et al. 2008). The resultant phylo-
genetic hypothesis was based on karyotype,
behavioral characters, and morphological char-
acters, and those results tentatively placed
L. curtatus near the base of Arvicolini, although
this hypothesis should be considered tenuous
(Robovský et al. 2008). If this phylogenetic
placement holds, the importance of under-
standing the evolutionary patterns within L.
curtatus becomes critical for allowing compar-
isons to the more speciose clade of Microtus.
As suggested by our data set and by previously
published records (e.g., Barnosky and Bell
2003), morphological patterns of various popu-
lations in the extant biota present a complex
224 WESTERN NORTH AMERICAN NATURALIST (2019), VOL. 79 NO. 2, PAGES 219–232
Fig. 3. Relative abundance (percentage of NISP) of morphotypes per collection locality.
mosaic across the landscape, with some popula-
tions having characteristically high abundance
of 6-triangle morphotypes. With such patterns
now at least preliminarily documented, it is
possible to begin to investigate the mechanistic
underpinnings that produce these patterns.
The driver(s) of the variation documented here
are unknown; possible explanations include
selection, genetic drift, or other phenomena
such as epigenetic polymorphism.
Teasing apart the evolutionary mechanisms
(e.g., selection and drift) underlying the mor-
phological variation in L. curtatus will require
further documentation of detailed population-
level data on dental morphology. Previous
quantitative approaches to examining varia-
tion of North American voles were applied to
the separation of species within morphological
space (e.g., Wallace 2006, McGuire 2011).
Quantitative intraspecific morphological com-
parisons exist for some taxa (e.g., Barnosky
1993, Piras et al. 2008, Ledevin et al. 2010),
and similar analyses may clarify our observa-
tions and help to contextualize our data across
the history of Lemmiscus. Quantification of
tooth variation across the spatio-temporal dis-
tribution of L. curtatus is outside the scope
of this paper but is ongoing (e.g., Burroughs
2016, 2017).
Acquisition of molecular-based phylogeo-
graphic sampling and full documentation of
quantitative genetic sampling for all popula-
tions of L. curtatus across its spatiotemporal
distribution are likely now attainable. Previ-
ously, it was impossible to collect molecular
information from fossil specimens of Lemmis-
cus, but advances in extraction and sequenc-
ing of ancient DNA now make this plausible.
Collectively, our observations highlight a poten-
tial path for developing a deeper understand-
ing of the evolutionary history of L. curtatus.
Tools that may assist in explaining how pat-
terns of dental variation are expressed devel-
opmentally are now in early stages of develop -
ment (e.g., Renvoisé et al. 2017) and promise
further insights in this field in coming years.
Our evaluation of morphological variation
in the m1 of L. curtatus from Saskatchewan
indicates a mosaic of morphotypes, with both
6-triangle morphologies and morphologies
approaching a 6-triangle state being more
abundant than noted elsewhere in modern
populations (e.g., Barnosky and Bell 2003).
Documentation of patterns of variation in
populations of L. curtatus begins to provide
the data necessary for elucidation of dental
evolution in the group. The rich fossil record
of L. curtatus and the changing expressions of
dental morphotypes through time and across
space make this a particularly interesting group
for explorations of this kind. The fact that
Lemmiscus is monotypic, and appears to have
been monotypic for its entire documented his-
tory, emphasizes that establishment of the
relationship between morphological patterns
and taxonomic boundaries remains a particu-
larly challenging problem. The data presented
here, combined with data derived from prior
studies, suggest that populations of L. curtatus
have strong differences in the propensity to
express variation in the m1, and that the varia-
tion that is expressed differs from place to
place. When considered in its entirety, the
North American fossil record of L. curtatus
expresses more dental variation than is ex -
pressed by other voles in the Pleistocene and
extant biotas, with the exception of Microtus
pennsylvanicus (Weddle and Choate 1983,
Davis 1987, Barnosky 1990, 1993) and Micro-
tus chrotorrhinus (Martin 1973). Meaningful
geographic patterns in expressed variation are
documented for M. pennsylvanicus (e.g., Wed-
dle and Choate 1983, Davis 1987), and are now
at least suggested for L. curtatus. Although we
have some understanding of how developmen-
tal biases create the structure underlying this
morphological variation, further work will be
required to determine why the variation in
our sample and in other populations of L. cur-
tatus is shaped the way that it is.
ACKNOWLEDGMENTS
Tim Schowalter collected, processed, and
sorted the owl pellets. Christina Barrón-Ortiz
translated the abstract. Conversations with
Corey Scobie and Christina Barrón-Ortiz led
to crucial references in the literature. Aman-
dah VanMerlin assisted with the production of
the map in Fig. 2.
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BELL ET AL.♦TOOTH MORPHOLOGY OF LEMMISCUS FROM SASKATCHEWAN 227
APPENDIX 1. Specimens of Lemmiscus curtatus examined for this study. Locality 1 = P17.13.1–P17.13.221; Locality 2 =
P17.13.222–P17.13.255; Locality 3 = P17.13.256–P17.13.290; Locality 4 = P17.13.291–P17.13.370.
Specimen number Side Element Morphotype
P17.13.1 Left Dentary, i1–m2 5T
P17.13.2 Left Dentary, i1–m2 5T
P17.13.3 Left Dentary, i1–m2 5T
P17.13.4 Left Dentary, i1–m2 5T
P17.13.5 Left Dentary, i1–m2 5T
P17.13.6 Left Dentary, i1–m2 5T
P17.13.7 Left Dentary, i1–m2 5T
P17.13.8 Left Dentary, i1–m2 5T
P17.13.9 Left Dentary, i1–m2 5T
P17.13.10 Left Dentary, i1–m2 5T
P17.13.11 Left Dentary, i1–m2 5T
P17.13.12 Left Dentary, i1–m2 5T
P17.13.13 Left Dentary, i1–m2 5T
P17.13.14 Left Dentary, i1–m2 5T
P17.13.15 Left Dentary, i1–m2 5T
P17.13.16 Left Dentary, i1–m2 5T
P17.13.17 Left Dentary, i1–m2 5T
P17.13.18 Left Dentary, i1–m2 5T
P17.13.19 Left Dentary, i1–m2 5T
P17.13.20 Right Dentary, i1–m2 5T
P17.13.21 Right Dentary, i1–m2 5T
P17.13.22 Right Dentary, i1–m2 5T
P17.13.23 Right Dentary, i1–m2 5T
P17.13.24 Right Dentary, i1–m2 5T
P17.13.25 Right Dentary, i1–m2 5T
P17.13.26 Right Dentary, i1–m2 5T
P17.13.27 Right Dentary, i1–m2 5T
P17.13.28 Right Dentary, i1–m2 5T
P17.13.29 Right Dentary, i1–m2 5T
P17.13.30 Right Dentary, i1–m2 5T
P17.13.31 Right Dentary, i1–m2 5T
P17.13.32 Right Dentary, i1–m2 5T
P17.13.33 Right Dentary, i1–m2 5T
P17.13.34 Right Dentary, i1–m2 5T
P17.13.35 Right Dentary, i1–m2 5T
P17.13.36 Right Dentary, i1–m2 5T
P17.13.37 Right Dentary, i1–m2 5T
P17.13.38 Left Dentary, i1–m3 5T
P17.13.39 Left Dentary, i1–m3 5T
P17.13.40 Left Dentary, i1–m3 5T
P17.13.41 Left Dentary, i1–m3 5T
P17.13.42 Left Dentary, i1–m3 5T
P17.13.43 Left Dentary, i1–m3 5T
P17.13.44 Left Dentary, i1–m3 5T
P17.13.45 Left Dentary, i1–m3 5T
P17.13.46 Left Dentary, i1–m3 5T
P17.13.47 Left Dentary, i1–m3 5T
P17.13.48 Left Dentary, i1–m3 5T
228 WESTERN NORTH AMERICAN NATURALIST (2019), VOL. 79 NO. 2, PAGES 219–232
APPENDIX 1. Continued.
Specimen number Side Element Morphotype
P17.13.49 Left Dentary, i1–m3 5T
P17.13.50 Left Dentary, i1–m3 5T
P17.13.51 Left Dentary, i1–m3 5T
P17.13.52 Left Dentary, i1–m3 5T
P17.13.53 Left Dentary, i1–m3 5T
P17.13.54 Left Dentary, i1–m3 5T
P17.13.55 Left Dentary, i1–m3 5T
P17.13.56 Left Dentary, i1–m3 5T
P17.13.57 Left Dentary, i1–m3 5T
P17.13.58 Left Dentary, i1–m3 5T
P17.13.59 Left Dentary, i1–m3 5T
P17.13.60 Left Dentary, i1–m3 5T
P17.13.61 Left Dentary, i1–m3 5T
P17.13.62 Left Dentary, i1–m3 5T
P17.13.63 Right Dentary, i1–m3 5T
P17.13.64 Right Dentary, i1–m3 5T
P17.13.65 Right Dentary, i1–m3 5T
P17.13.66 Right Dentary, i1–m3 5T
P17.13.67 Right Dentary, i1–m3 5T
P17.13.68 Right Dentary, i1–m3 5T
P17.13.69 Right Dentary, i1–m3 5T
P17.13.70 Right Dentary, i1–m3 5T
P17.13.71 Right Dentary, i1–m3 5T
P17.13.72 Right Dentary, i1–m3 5T
P17.13.73 Right Dentary, i1–m3 5T
P17.13.74 Right Dentary, i1–m3 5T
P17.13.75 Right Dentary, i1–m3 5T
P17.13.76 Right Dentary, i1–m3 5T
P17.13.77 Right Dentary, i1–m3 5T
P17.13.78 Right Dentary, i1–m3 5T
P17.13.79 Right Dentary, i1–m3 5T
P17.13.80 Right Dentary, i1–m3 5T
P17.13.81 Right Dentary, i1–m3 5T
P17.13.82 Right Dentary, i1–m3 5T
P17.13.83 Right Dentary, i1–m3 5T
P17.13.84 Right Dentary, i1–m3 5T
P17.13.85 Right Dentary, i1–m3 5T
P17.13.86 Right Dentary, i1–m3 5T
P17.13.87 Right Dentary, i1–m3 5T
P17.13.88 Right Dentary, i1–m3 5T
P17.13.89 Right Dentary, i1–m3 5T
P17.13.90 Right Dentary, i1, m1 5T
P17.13.91 Left Dentary, i1, m1, m3 5T
P17.13.92 Left Dentary, i1, m1, m3 5T
P17.13.93 Right Dentary, i1, m1, m3 5T
P17.13.94 Right Dentary, i1, m1, m3 5T
P17.13.95 Left Dentary, m1, m2 5T
P17.13.96 Right Dentary, m1, m2 5T
P17.13.97 Left m1 5T
P17.13.98 Left m1 5T
P17.13.99 Right m1 5T
P17.13.100 Right m1 5T
P17.13.101 Right m1 5T
P17.13.102 Left Partial Dentary, i1–m2 5T
P17.13.103 Right Partial Dentary, i1–m2 5T
P17.13.104 Left Partial Dentary, i1, m1 5T
P17.13.105 Right Dentary, i1, m1 5T, Microtus-like cap
morphology
P17.13.106 Left Dentary, i1–m2 5T, T6 incipient closure
P17.13.107 Left Dentary, i1–m2 5T, T6 incipient closure
P17.13.108 Right Dentary, i1–m2 5T, T6 incipient closure
P17.13.109 Right Dentary, i1–m2 5T, T6 incipient closure
P17.13.110 Right Dentary, i1–m2 5T, T6 incipient closure
P17.13.111 Right Dentary, i1–m2 5T, T6 incipient closure
P17.13.112 Right Dentary, i1–m2 5T, T6 incipient closure
BELL ET AL.♦TOOTH MORPHOLOGY OF LEMMISCUS FROM SASKATCHEWAN 229
APPENDIX 1. Continued.
Specimen number Side Element Morphotype
P17.13.113 Right Dentary, i1–m2 5T, T6 incipient closure
P17.13.114 Left Dentary, i1–m3 5T, T6 incipient closure
P17.13.115 Left Dentary, i1–m3 5T, T6 incipient closure
P17.13.116 Left Dentary, i1–m3 5T, T6 incipient closure
P17.13.117 Left Dentary, i1–m3 5T, T6 incipient closure
P17.13.118 Left Dentary, i1–m3 5T, T6 incipient closure
P17.13.119 Left Dentary, i1–m3 5T, T6 incipient closure
P17.13.120 Left Dentary, i1–m3 5T, T6 incipient closure
P17.13.121 Left Dentary, i1–m3 5T, T6 incipient closure
P17.13.122 Left Dentary, i1–m3 5T, T6 incipient closure
P17.13.123 Left Dentary, i1–m3 5T, T6 incipient closure
P17.13.124 Left Dentary, i1–m3 5T, T6 incipient closure
P17.13.125 Right Dentary, i1–m3 5T, T6 incipient closure
P17.13.126 Right Dentary, i1–m3 5T, T6 incipient closure
P17.13.127 Right Dentary, i1–m3 5T, T6 incipient closure
P17.13.128 Right Dentary, i1–m3 5T, T6 incipient closure
P17.13.129 Right Dentary, i1–m3 5T, T6 incipient closure
P17.13.130 Right Dentary, i1–m3 5T, T6 incipient closure
P17.13.131 Right Dentary, i1–m3 5T, T6 incipient closure
P17.13.132 Right Dentary, i1–m3 5T, T6 incipient closure
P17.13.133 Right Dentary, i1–m3 5T, T6 incipient closure
P17.13.134 Right Dentary, i1–m3 5T, T6 incipient closure
P17.13.135 Right Dentary, i1, m1, m3 5T, T6 incipient closure
P17.13.136 Left Dentary, m1–m3 5T, T6 incipient closure
P17.13.137 Left Dentary, m1–m3 5T, T6 incipient closure
P17.13.138 Left m1 5T, T6 incipient closure
P17.13.139 Right m1 5T, T6 incipient closure
P17.13.140 Left Dentary, i1–m2 5T, T6 pinched
P17.13.141 Left Dentary, i1–m2 5T, T6 pinched
P17.13.142 Left Dentary, i1–m2 5T, T6 pinched
P17.13.143 Left Dentary, i1–m2 5T, T6 pinched
P17.13.144 Left Dentary, i1–m2 5T, T6 pinched
P17.13.145 Left Dentary, i1–m2 5T, T6 pinched
P17.13.146 Left Dentary, i1–m2 5T, T6 pinched
P17.13.147 Left Dentary, i1–m2 5T, T6 pinched
P17.13.148 Left Dentary, i1–m2 5T, T6 pinched
P17.13.149 Left Dentary, i1–m2 5T, T6 pinched
P17.13.150 Left Dentary, i1–m2 5T, T6 pinched
P17.13.151 Left Dentary, i1–m2 5T, T6 pinched
P17.13.152 Right Dentary, i1–m2 5T, T6 pinched
P17.13.153 Right Dentary, i1–m2 5T, T6 pinched
P17.13.154 Right Dentary, i1–m2 5T, T6 pinched
P17.13.155 Right Dentary, i1–m2 5T, T6 pinched
P17.13.156 Right Dentary, i1–m2 5T, T6 pinched
P17.13.157 Right Dentary, i1–m2 5T, T6 pinched
P17.13.158 Right Dentary, i1–m2 5T, T6 pinched
P17.13.159 Right Dentary, i1–m2 5T, T6 pinched
P17.13.160 Right Dentary, i1–m2 5T, T6 pinched
P17.13.161 Right Dentary, i1–m2 5T, T6 pinched
P17.13.162 Right Dentary, i1–m2 5T, T6 pinched
P17.13.163 Left Dentary, i1–m3 5T, T6 pinched
P17.13.164 Left Dentary, i1–m3 5T, T6 pinched
P17.13.165 Left Dentary, i1–m3 5T, T6 pinched
P17.13.166 Left Dentary, i1–m3 5T, T6 pinched
P17.13.167 Left Dentary, i1–m3 5T, T6 pinched
P17.13.168 Left Dentary, i1–m3 5T, T6 pinched
P17.13.169 Left Dentary, i1–m3 5T, T6 pinched
P17.13.170 Left Dentary, i1–m3 5T, T6 pinched
P17.13.171 Left Dentary, i1–m3 5T, T6 pinched
P17.13.172 Left Dentary, i1–m3 5T, T6 pinched
P17.13.173 Left Dentary, i1–m3 5T, T6 pinched
P17.13.174 Left Dentary, i1–m3 5T, T6 pinched
P17.13.175 Left Dentary, i1–m3 5T, T6 pinched
P17.13.176 Left Dentary, i1–m3 5T, T6 pinched
P17.13.177 Left Dentary, i1–m3 5T, T6 pinched
230 WESTERN NORTH AMERICAN NATURALIST (2019), VOL. 79 NO. 2, PAGES 219–232
APPENDIX 1. Continued.
Specimen number Side Element Morphotype
P17.13.178 Left Dentary, i1–m3 5T, T6 pinched
P17.13.179 Right Dentary, i1–m3 5T, T6 pinched
P17.13.180 Right Dentary, i1–m3 5T, T6 pinched
P17.13.181 Right Dentary, i1–m3 5T, T6 pinched
P17.13.182 Right Dentary, i1–m3 5T, T6 pinched
P17.13.183 Right Dentary, i1–m3 5T, T6 pinched
P17.13.184 Right Dentary, i1–m3 5T, T6 pinched
P17.13.185 Right Dentary, i1–m3 5T, T6 pinched
P17.13.186 Right Dentary, i1–m3 5T, T6 pinched
P17.13.187 Right Dentary, i1–m3 5T, T6 pinched
P17.13.188 Right Dentary, i1–m3 5T, T6 pinched
P17.13.189 Right Dentary, i1–m3 5T, T6 pinched
P17.13.190 Right Dentary, i1–m3 5T, T6 pinched
P17.13.191 Right Dentary, i1–m3 5T, T6 pinched
P17.13.192 Right Dentary, i1–m3 5T, T6 pinched
P17.13.193 Right Dentary, i1–m3 5T, T6 pinched
P17.13.194 Right Dentary, i1–m3 5T, T6 pinched
P17.13.195 Right Dentary, i1–m3 5T, T6 pinched
P17.13.196 Right Dentary, i1, m1 5T, T6 pinched
P17.13.197 Right Dentary, i1, m1, m3 5T, T6 pinched
P17.13.198 Right Dentary, m1, m2 5T, T6 pinched
P17.13.199 Left m1 5T, T6 pinched
P17.13.200 Left m1 5T, T6 pinched
P17.13.201 Left m1 5T, T6 pinched
P17.13.202 Left m1 5T, T6 pinched
P17.13.203 Left m1 5T, T6 pinched
P17.13.204 Right Dentary, m1 5T, T6 pinched
P17.13.205 Left Dentary, i1–m2 6T
P17.13.206 Left Dentary, i1–m2 6T
P17.13.207 Right Dentary, i1–m2 6T
P17.13.208 Right Dentary, i1–m2 6T
P17.13.209 Left Dentary, i1–m3 6T
P17.13.210 Left Dentary, i1–m3 6T
P17.13.211 Left Dentary, i1–m3 6T
P17.13.212 Left Dentary, i1–m3 6T
P17.13.213 Left Dentary, i1–m3 6T
P17.13.214 Right Dentary, i1–m3 6T
P17.13.215 Right Dentary, i1–m3 6T
P17.13.216 Right Dentary, i1–m3 6T
P17.13.217 Right Dentary, i1–m3 6T
P17.13.218 Left m1 6T
P17.13.219 Right m1 6T
P17.13.220 Right Partial Dentary, m1 6T
P17.13.221 Left Dentary, i1–m3 6T, T4/T5 confluent
P17.13.222 Left Dentary, i1–m2 5T
P17.13.223 Left Dentary, i1–m2 5T
P17.13.224 Left Dentary, i1–m3 5T
P17.13.225 Left Dentary, i1–m3 5T
P17.13.226 Left Dentary, i1–m3 5T
P17.13.227 Right Dentary, i1–m2 5T
P17.13.228 Right Dentary, i1–m2 5T
P17.13.229 Right Dentary, i1–m2 5T
P17.13.230 Right Dentary, i1–m2 5T
P17.13.231 Right Dentary, i1–m3 5T
P17.13.232 Right Dentary, i1–m3 5T
P17.13.233 Right Dentary, i1–m3 5T
P17.13.234 Left Dentary, i1–m2 5T, T6 incipient closure
P17.13.235 Left Dentary, i1–m3 5T, T6 incipient closure
P17.13.236 Left Dentary, m1, m2 5T, T6 incipient closure
P17.13.237 Right Dentary, i1–m2 5T, T6 incipient closure
P17.13.238 Right Dentary, i1–m2 5T, T6 incipient closure
P17.13.239 Right Dentary, i1–m3 5T, T6 incipient closure
P17.13.240 Right Dentary, i1–m3 5T, T6 incipient closure
P17.13.241 Left Dentary, i1–m2 5T, T6 pinched
P17.13.242 Left Dentary, i1–m3 5T, T6 pinched
BELL ET AL.♦TOOTH MORPHOLOGY OF LEMMISCUS FROM SASKATCHEWAN 231
APPENDIX 1. Continued
Specimen number Side Element Morphotype
P17.13.243 Left Dentary, i1–m3 5T, T6 pinched
P17.13.244 Left Dentary, i1–m3 5T, T6 pinched
P17.13.245 Left Dentary, i1, m1 5T, T6 pinched
P17.13.246 Left Dentary, m1, m2 5T, T6 pinched
P17.13.247 Right Dentary, i1–m2 5T, T6 pinched
P17.13.248 Right Dentary, i1–m2 5T, T6 pinched
P17.13.249 Right Dentary, i1–m3 5T, T6 pinched
P17.13.250 Right Dentary, i1–m3 5T, T6 pinched
P17.13.251 Right Dentary, i1–m3 5T, T6 pinched
P17.13.252 Right Dentary, i1–m3 5T, T6 pinched
P17.13.253 Right Dentary, i1–m3 5T, T6 pinched
P17.13.254 Left Dentary, i1–m3 6T
P17.13.255 Left Dentary, i1–m3 6T
P17.13.256 Left Dentary, i1–m2 5T
P17.13.257 Left Dentary, i1–m2 5T
P17.13.258 Left Dentary, i1–m2 5T
P17.13.259 Left Dentary, i1–m2 5T
P17.13.260 Left Dentary, i1–m2 5T
P17.13.261 Left Dentary, i1–m2 5T
P17.13.262 Left Dentary, i1–m3 5T
P17.13.263 Left Dentary, i1–m3 5T
P17.13.264 Left Dentary, i1–m3 5T
P17.13.265 Left Dentary, i1–m3 5T
P17.13.266 Left Dentary, m1 5T
P17.13.267 Left Dentary, m1, m2 5T
P17.13.268 Left Dentary, m1, m2 5T
P17.13.269 Left m1 5T
P17.13.270 Left m1 5T
P17.13.271 Right Dentary, i1–m2 5T
P17.13.272 Right Dentary, i1–m2 5T
P17.13.273 Right Dentary, i1–m3 5T
P17.13.274 Right Dentary, i1–m3 5T
P17.13.275 Right Dentary, i1–m3 5T
P17.13.276 Right Dentary, i1–m3 5T
P17.13.277 Right Dentary, i1–m3 5T
P17.13.278 Right Dentary, i1, m1, m3 5T
P17.13.279 Right Dentary, m1, m2 5T
P17.13.280 Right Dentary, m1, m2 5T
P17.13.281 Left Dentary, m1–m3 5T, T6 incipient closure
P17.13.282 Right Dentary, i1–m2 5T, T6 incipient closure
P17.13.283 Right Dentary, i1–m3 5T, T6 incipient closure
P17.13.284 Left Dentary, i1–m2 5T, T6 pinched
P17.13.285 Right Dentary, i1–m2 5T, T6 pinched
P17.13.286 Right Dentary, i1–m2 5T, T6 pinched
P17.13.287 Right Dentary, i1–m2 5T, T6 pinched
P17.13.288 Right Dentary, i1–m2 5T, T6 pinched
P17.13.289 Left Dentary, i1–m2 6T
P17.13.290 Left Dentary, i1–m2 6T
P17.13.291 Left Dentary, i1–m2 5T
P17.13.292 Left Dentary, i1–m2 5T
P17.13.293 Left Dentary, i1–m2 5T
P17.13.294 Left Dentary, i1–m2 5T
P17.13.295 Left Dentary, i1–m2 5T
P17.13.296 Left Dentary, i1–m2 5T
P17.13.297 Left Dentary, i1–m2 5T
P17.13.298 Left Dentary, i1–m2 5T
P17.13.299 Left Dentary, i1–m2 5T
P17.13.300 Left Dentary, i1–m3 5T
P17.13.301 Left Dentary, i1–m3 5T
P17.13.302 Left Dentary, i1–m3 5T
P17.13.303 Left Dentary, i1–m3 5T
P17.13.304 Left Dentary, i1–m3 5T
P17.13.305 Left Dentary, i1–m3 5T
P17.13.306 Left Dentary, i1–m3 5T
P17.13.307 Left Dentary, i1–m3 5T
232 WESTERN NORTH AMERICAN NATURALIST (2019), VOL. 79 NO. 2, PAGES 219–232
APPENDIX 1. Continued.
Specimen number Side Element Morphotype
P17.13.308 Left Dentary, i1–m3 5T
P17.13.309 Left Dentary, i1, m1 5T
P17.13.310 Left Dentary, i1, m1 5T
P17.13.311 Left m1 5T
P17.13.312 Left m1 5T
P17.13.313 Right Dentary, i1–m2 5T
P17.13.314 Right Dentary, i1–m2 5T
P17.13.315 Right Dentary, i1–m2 5T
P17.13.316 Right Dentary, i1–m2 5T
P17.13.317 Right Dentary, i1–m2 5T
P17.13.318 Right Dentary, i1–m2 5T
P17.13.319 Right Dentary, i1–m2 5T
P17.13.320 Right Dentary, i1–m2 5T
P17.13.321 Right Dentary, i1–m2 5T
P17.13.322 Right Dentary, i1–m2 5T
P17.13.323 Right Dentary, i1–m2 5T
P17.13.324 Right Dentary, i1–m3 5T
P17.13.325 Right Dentary, i1–m3 5T
P17.13.326 Right Dentary, i1–m3 5T
P17.13.327 Right Dentary, i1–m3 5T
P17.13.328 Right Dentary, i1–m3 5T
P17.13.329 Right Dentary, i1–m3 5T
P17.13.330 Right Dentary, i1–m3 5T
P17.13.331 Right Dentary, m1, m2 5T
P17.13.332 Right Dentary, m1, m2 5T
P17.13.333 Right m1 5T
P17.13.334 Left Dentary, i1–m2 5T, T6 incipient closure
P17.13.335 Left Dentary, i1–m3 5T, T6 incipient closure
P17.13.336 Left m1 5T, T6 incipient closure
P17.13.337 Right Dentary, i1–m3 5T, T6 incipient closure
P17.13.338 Right Dentary, i1–m3 5T, T6 incipient closure
P17.13.339 Right Dentary, i1–m3 5T, T6 incipient closure
P17.13.340 Left Dentary, i1–m2 5T, T6 pinched
P17.13.341 Left Dentary, i1–m2 5T, T6 pinched
P17.13.342 Left Dentary, i1–m2 5T, T6 incipient closure
P17.13.343 Left Dentary, i1–m2 5T, T6 pinched
P17.13.344 Left Dentary, i1–m2 5T, T6 pinched
P17.13.345 Left Dentary, i1–m2 5T, T6 pinched
P17.13.346 Left Dentary, i1–m2 5T, T6 pinched
P17.13.347 Left Dentary, i1–m3 5T, T6 pinched
P17.13.348 Left Dentary, i1–m3 5T, T6 pinched
P17.13.349 Left Dentary, i1–m3 5T, T6 pinched
P17.13.350 Right Dentary, i1–m2 5T, T6 pinched
P17.13.351 Right Dentary, i1–m2 5T, T6 pinched
P17.13.352 Right Dentary, i1–m2 5T, T6 pinched
P17.13.353 Right Dentary, i1–m2 5T, T6 pinched
P17.13.354 Right Dentary, i1–m2 5T, T6 pinched
P17.13.355 Right Dentary, i1–m3 5T, T6 pinched
P17.13.356 Right Dentary, i1–m3 5T, T6 pinched
P17.13.357 Right Dentary, i1–m3 5T
P17.13.358 Right Dentary, i1–m3 5T
P17.13.359 Right Dentary, i1–m3 5T, T6 pinched
P17.13.360 Right Dentary, i1–m3 5T, T6 pinched
P17.13.361 Right Dentary, m1, m2 5T, T6 pinched
P17.13.362 Right Dentary, m1, m2 5T, T6 pinched
P17.13.363 Right m1 5T, T6 pinched
P17.13.364 Left Dentary, i1–m2 6T
P17.13.365 Left Dentary, i1–m3 6T
P17.13.366 Left Dentary, m1, m2 6T
P17.13.367 Right Dentary, i1–m2 6T
P17.13.368 Right Dentary, i1–m2 6T
P17.13.369 Right Dentary, i1–m2 6T
P17.13.370 Right Dentary, i1–m2 4T, T5/T6 confluent,
T6 incipient closure
