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A new species in the Peromyscus boylii species group (Cricetidae:
Neotominae) from Michoacán, México
RobeRt D. bRaDley,* Nicté oRDóñez-GaRza, GeRaRDo ceballos, Duke s. RoGeRs, aND DaviD J. schmiDly
Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409-3131, USA (RDB, NO-G)
Museum of Texas Tech University, Lubbock, TX 79409-3191, USA (RDB)
Laboratorio de Conservación y Manejo de Vertebrados, Instituto de Ecología, Universidad Nacional Autónoma de México,
A.P. 70-275 Ciudad Universitaria, 04510 México D.F., México (GC)
Department of Biology, Brigham Young University, Provo, UT 84602, USA (DSR)
Monte L. Bean Life Science Museum, Brigham Young University, Provo, UT 84602, USA (DSR)
Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA (DJS)
* Correspondent: robert.bradley@ttu.edu
Specimens of the Peromyscus boylii species group occurring in the montane regions of Michoacán, México,
historically have been assigned to P. levipes. However, previous studies have shown that some specimens from
eastern Michoacán possessed mitochondrial DNA haplotypes and karyotypes that were distinct from P. levipes
and other members of the P. boylii species group. Phylogenetic analyses (parsimony and likelihood) of additional
DNA sequences obtained from the mitochondrial cytochrome-b gene indicated that specimens from central and
eastern Michoacán and western Morelos formed a monophyletic clade that was sister to a clade containing
representatives of P. beatae. Estimations of genetic divergence for members of these 2 sister clades exceeded
5% and were greater than most pairwise comparisons reported for other members of the P. boylii species group.
Collectively, there are no discernable morphological differences between those specimens and other cryptic
species in the P. boylii species group. Together, these results indicated that specimens from the Sierra Madre
del Sur region of Michoacán, Morelos, and likely throughout the Neovolcanic Axis of the Estado de México
represent an undescribed species of Peromyscus for which we propose the name Peromyscus kilpatricki.
Especímenes del grupo especies de Peromyscus boylii que ocurren en las regiones montañosas de Michoacán,
México, han sido tradicionalmente asignadas a P. levipes. Sin embargo, estudios previos indican que algunos
especímenes del Este de Michoacán tienen haplotipos mitocondriales y cariotipos que son distintos a los de P. levipes
y a los de otros miembros del grupo de especies de P. boylii. Análisis filogenéticos (parsimonia y verosimilitud)
de secuencias adicionales de ADN obtenidas del gen mitocondrial citocromo-b indicaron que los ejemplares del
centro y este de Michoacán y oeste de Morelos formaron un clado hermano a un clado que contiene representantes
de P. beatae. Estimaciones de divergencia genética de miembros de estos 2 clados hermanos exceden del 5% y
fueron mayores que la mayoría de comparaciones pareadas reportadas para otros miembros del grupo de especies
de P. boylii. Colectivamente, no hay diferencias morfológicas entre los especímenes del este de Michoacán y
otras especies crípticas del grupo de P. boylii. En conjunto, estos resultados indicaron que los especímenes de la
región de Sierra Madre del Sur de Michoacán, Morelos, y posiblemente la región central del Estado de México
representan una especie no descrita de Peromyscus, para la cual proponemos el nombre Peromyscus kilpatricki.
Key words: cryptic species, cytochrome-b gene, karyotype, morphology, Peromyscus, P. boylii species group
Resolving the systematic and taxonomic relationships within the
Peromyscus boylii species group has been an active endeavor
over the last 35 years. Since 1977, 2 species were described
(P. schmidlyi Bradley et al. 2004, and P. carletoni Bradley et al.
2014); 5 taxa previously recognized as subspecies of P. boylii
were elevated to the species level (P. madrensis, P. simulus, and
Journal of Mammalogy, xx(x):1–12, 2016
DOI:10.1093/jmammal/gyw160
Version of Record, first published online December 9, 2016, with fixed content and layout in compliance with Art. 8.1.3.2 ICZN.
© The Author 2016. Published by Oxford University Press on behalf of American Society of Mammalogists.
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://
creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the
original work is properly cited. For commercial re-use, please contact journals.permissions@oup.com
Journal of Mammalogy Advance Access published December 9, 2016
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2 JOURNAL OF MAMMALOGY
P. spicilegus [see Carleton 1977], P. beatae, and P. levipes [see
Houseal et al. 1987; Rennert and Kilpatrick 1987; Schmidly
et al. 1988]); and 2 subspecies were reassigned to other spe-
cies (P. boylii ambiguus to P. levipes [see Castro-Campillo et al.
1999], and P. boylii sacarensis to P. beatae [see Bradley et al.
2000]). Despite these advances, several taxonomic issues remain
unresolved in this species group, especially in the poorly studied
regions of eastern and southwestern México.
Houseal et al. (1987) summarized the karyotypic diver-
sity within the P. boylii species group and based on number
of autosomal chromosomes in the karyotype (FN) identified 3
potentially undescribed taxa from Michoacán, México. Those
taxa had karyotypes (FN = 54, FN = 56, and FN = 65–66, 68,
respectively) that were either distinct from other members of
the P. boylii species group (beatae, boylii, levipes, madrensis,
and simulus) or their distinct geographic distribution precluded
an association with named taxa. Allozymic data (Rennert and
Kilpatrick 1987) revealed that the Michoacán populations (cor-
responding to the FN = 56 and FN = 65–66, 68 forms) were
genetically divergent from each other and from other mem-
bers of the P. boylii species group; however, no fixed genic
differences were apparent. More recently, Tiemann-Boege
et al. (2000) reported a unique mitochondrial cytochrome-b
(Cytb) haplotype for specimens from western Michoacán and
suggested that those specimens represented an undescribed
species. Despite this relatively high level of genetic differen-
tiation, there has been a low level of accompanying morpho-
logical divergence reported among members of the P. boylii
species group (Schmidly et al. 1988; Castro-Campillo et al.
1999; Bradley et al. 2004, 2014). In addition, given the conflu-
ence of diverse morphotectonic provinces in this region, such
as the Trans-Mexican Volcanic Belt and Sierra Madre del Sur
(Ferrusquía-Villfranca 1993), it would not be surprising that
these genetically distinct populations might prove to be cryp-
tic species, hidden within the overall conservative morphology
that exemplifies the P. boylii species group.
In this study, efforts were focused on determining the taxo-
nomic status of populations distributed in the high-elevation
(> 1,900 m) pine-oak forests (Pinus spp. and Quercus spp.)
of Michoacán, Estado de México, and Morelos. In addition,
phylogenetic relationships of these populations were examined
relative to other members of the P. boylii species group.
Materials and Methods
Samples.—Eight individuals were obtained from 3 naturally
occurring populations in Michoacán, México and 1 local-
ity in Morelos, México (Localities 16–19; Fig. 1). Cytb DNA
sequences from 36 individuals, representing 15 species and 2
presumably undescribed taxa, reported in Bradley et al. (2000,
Fig. 1.—Distribution of selected populations and species of the Peromyscus boylii species group from western Mexico and surrounding states.
Emphasis was placed on depicting the newly described species and its closest phylogenetic allies or taxa with similar karyotypes. Closed circles
represent collecting localities and numbers refer to samples listed in Appendix I. Localities A, B, and 16–19 represent the new species (P. species
novum).
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BRADLEY ET AL.—A CRYPTIC SPECIES OF PEROMYSCUS 3
2004, 2007, 2014), Tiemann-Boege et al. (2000), and this study,
were included as internal references and outgroup comparisons.
Specimens were collected following methods outlined in the
ASM Guidelines (Sikes et al. 2016) and approved by the Texas
Tech University Animal Care and Use Committee. Specimen
numbers and collection localities are listed in Appendix I.
Karyotypic data.—One individual of Peromyscus from
Zitácuaro, Michoacán, was karyotyped following the bone mar-
row method of Baker and Qumsiyeh (1988). At least 5 meta-
phase spreads were examined and photographed. Karyograms
were constructed based on chromosomal morphology pre-
sented in Committee for Standardization of Chromosomes
of Peromyscus (1977) and Greenbaum et al. (1994) and were
compared to karyotypes and FNs (Table 1) previously reported
by Lee et al. (1972), Schmidly and Schroeter (1974), Houseal
et al. (1987), Smith (1990), and Bradley et al. (2014).
Sequence data.—Mitochondrial DNA was isolated from
approximately 0.1 g of frozen liver tissue using the DNeasy
kit (Qiagen, Valencia, California). The entire Cytb gene
(1,143 bp) was amplified using the polymerase chain reaction
(PCR) method (Saiki et al. 1988) and the following primers:
MVZ05 (Smith and Patton 1993) and PERO3′ (Tiemann-
Boege et al. 2000) or primer pairs L14724 with CBH3 (Irwin
et al. 1991; Palumbi 1996) and F1 with H15915 (Irwin et al.
1991; Whiting et al. 2003). Thermal profiles for PCR were as
follows: initial denaturation at 95°C for 2 min, followed by 35
cycles of denaturation at 95°C for 1 min, annealing at 51°C
for 1 min, and extension at 72°C for 2 min, with a final exten-
sion at 72°C for 7 min. Most PCR products were purified with
either an ExoSAP-IT (Affymetrix, Santa Clara, California) or
QIAquick PCR Purification Kit (Qiagen, Valencia, California)
or the Millipore Multiscreen™ 96-Well Filtration System
(Cat. No. MANU03050). Primers used to cycle sequence the
products included: WDRAT1100, 400R, 700H, and NEO700L
(Peppers and Bradley 2000), and 400F (Tiemann-Boege et al.
2000), H15915, L14724, F1, and CB3H. Cycle sequenc-
ing reactions were purified using isopropanol cleanup proto-
cols and were analyzed with an ABI 3100-Avant automated
sequencer and ABI Prism Big Dye version 3.1 terminator tech-
nology (Applied Biosystems, Foster City, California) or using
Millipore Multiscreen™ Filter Plates for High Throughput
Separations (Cat. No. MAHVN4510) with a Perkin-Elmer
ABI Prism 377. Resulting sequences were aligned and proofed
using Sequencher 4.0 or 4.1.2 software (Gene Codes, Ann
Arbor, Michigan); chromatograms were examined to verify all
base changes. All Cytb sequences obtained in this study were
deposited in GenBank and are listed in Appendix I.
Using the phylogenetic relationships of the genus Peromyscus
presented in Bradley et al. (2007), P. gratus was selected as
the outgroup taxon for all sequence analyses. Representatives
of all currently recognized members of the P. boylii species
group (beatae, boylii, carletoni, levipes, madrensis, schmidlyi,
simulus, and stephani) were included in analyses as internal
standards. In addition, members of the P. aztecus species group
(aztecus, evides, hylocetes, oaxacensis, spicilegus, and winkl-
emanni) and 1 undescribed taxon with apparent affiliations to
the P. boylli species group were included based on their chro-
mosomal similarities or geographic proximity.
A parsimony analysis (PAUP*—Swofford 2002) was con-
ducted using equally weighted characters and variable nucleo-
tide positions treated as unordered, discrete characters with 4
possible states: A, C, G, or T. Phylogenetically uninformative
characters were excluded from analyses. The heuristic search
and tree-bisection-reconnection options in PAUP* (version
4.0a149—Swofford 2002) were used to find the most-parsi-
monious trees. A strict consensus tree was generated from the
available trees and the bootstrap (BS) analysis (Felsenstein
1985) with 1,000 iterations was used to evaluate nodal support.
Table 1.—Comparison of karyotypes for members of the Peromyscus boylii species group examined in this study. All chromosomal assess-
ments are based on nondifferentially stained karyotypes as interpreted from comparisons to data presented in or cited by Houseal et al. (1987)
and Smith (1990). Only chromosomes that have been identified as biarmed for the P. boylii species group are included. All karyotypes possessed
a biarmed condition for chromosomes 1, 22, and 23 (except in some populations of P. beatae—see Davis et al. 1986). Abbreviations are as fol-
lows: a = acrocentric, b = biarmed, and p = polymorphic. References: 1 = Lawlor (1971), 2 = Lee et al. (1972), 3 = Schmidly and Schroeter 1974,
4 = Carleton et al. (1982), 5 = Houseal et al. (1987), 6 = Smith (1990), 7 = Bradley et al. (2004), 8 = Bradley et al. (2014), and 9 = this study.
Taxon FN Chromosome Reference
234567891013
P. beatae 48–54 p a a a a a a a a a 5, 6
P. boylii 52aaaaaaaa a a 5
P. carletoni 66ab b a b b b a b b a 4, 8
P. levipes 56–60 b p a a p a a b a a 5, 6
P. madrensis 54 a a a a a a a b a a 4
P. schmidlyi 54–56 p a a a a a a p a a 2, 3, 7
P. simulus 52 aaaaaaaa a a 4
P. stephani 52 aaaaaaaa a a 1
P. new species (Zitácuaro, Michoacán; n = 1) 56 b a a a a a a b a a 8, 9
P. new species (Los Azufres, Michoacán; n = 3) 56 b a a a a a a b a a 5
P. new species (Pátzcuaro, Michoacán; n = 1) 56 b a a a a a a b a a 5
P. sp2 (Dos Aguas, Michoacán; n = 5) 65, 66, 68 b b a b b p a b p p 5
P. sp2 (Zinapécuaro, Michoacán; n = 4) 68 b b a b b b a b b b 8, 9
aBradley et al. (2014) discuss an aberrant karyotype for P. carletoni.
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4 JOURNAL OF MAMMALOGY
Fifty-six maximum likelihood models were evaluated using
MODELTEST (Posada and Crandall 1998) in order to deter-
mine the model of DNA evolution best fitting the data. The
Akaike information criterion identified HKY+I+G as being
the most appropriate model, relative to complexity of model,
for this data set. This model generated significantly better
likelihood scores (−lnL = 5,305.4365) than all other mod-
els and included the following parameters: base frequencies
(A = 0.3326, C = 0.3006, G = 0.1079, T = 0.2589), propor-
tion of invariable sites (I = 0.5952), and gamma distribution
(G = 1.2044).
Bayesian inference methods (MrBayes—Huelsenbeck and
Ronquist 2001) were used in a maximum likelihood framework
and to generate clade probabilities values indicative of nodal
support. The HKY+I+G model was used and parameters were
estimated within the analysis. The analysis was run with the
following options: 4 Markov chains, 10 million generations,
and sample frequency = every 1,000th generation. Following a
visual inspection of likelihood scores, the 1st 1,000 trees were
discarded and a consensus tree (50% majority rule) was con-
structed from the remaining trees.
The Kimura 2-parameter model of evolution (Kimura 1980)
was used to calculate genetic distances between selected taxa.
These values were used to assess levels of genetic divergence
following criteria outlined in Bradley and Baker (2001) and
Baker and Bradley (2006).
Morphometric data.—Eighteen cranial measurements
(defined in Carleton et al. 1982) were recorded in millime-
ters (mm) from adults or were obtained from previous studies
(Bradley et al. 2014). Only adults (age classes IV–VI), identi-
fied as such based on patterns of molar tooth wear (Schmidly
1973), were included in this study. Measurements are as fol-
lows: greatest length of skull (GLS), length of auditory bulla
(LAB), postpalatal length (PPL), length of mesopterygoid fossa
(LMF), palatal length (PL), length of incisive foramen (LIF),
length of molar toothrow (LMT), greatest zygomatic breadth
(ZB), mastoidal breadth (MB), greatest breadth across molars
(GBM), postdental palatal breadth (PPB), greatest width of
mesopterygoid fossa (WMF), depth of braincase (DB), breadth
of braincase (BB), least interorbital width (LIW), rostral
breadth (RB), nasal length (NL), and rostral length (RL).
Statistical analyses of morphologic data.—For the 18 cra-
nial characters, measurements were included from specimens
collected at the following localities in Michoacán: Zitacuaro
(n = 6), Uruapan (n = 41), Los Azufres (n = 1), Opopeo (n = 2),
Pátzcuaro (n = 1), Quiroga (n = 1), Sierra Carcalosa (n = 2),
and Dos Aguas (n = 10). These populations were compared to
other populations delimited by previous allozyme, karyotypic
morphologic, and genetic studies (Houseal et al. 1987; Rennert
and Kilpatrick 1987; Schmidly et al. 1988; Bradley et al. 2004,
2014) to represent samples of P. beatae (n = 32), P. boylii
(n = 44), P. carletoni (n = 54), P. levipes (n = 85), P. schmidlyi
(n = 9), and P. simulus (n = 15). For all analyses, sexes were
combined following Schmidly et al. (1988).
For descriptive and comparative purposes, means, ranges,
and SEs were calculated for each character and species; for all
further analyses, characters were log-transformed (natural log).
Specimens with missing measurements were excluded from
analyses. The Shapiro–Wilk normality test (Shapiro and Wilk
1965) was performed to test for normality among the data. Not
all the variables were normally distributed; therefore, a non-
parametric 1-way analysis of variance (ANOVA), the Kruskal–
Wallis test (Kruskal and Wallis 1952; 1-way ANOVA on ranks
test), was performed to determine if statistically significant
differences existed between 2 or more groups. A Dunn post
hoc test (Dunn 1964) with adjustment for P-value using the
Bonferroni correction method (Ury 1976) was then applied to
the results of the Kruskal–Wallis test, and a probability level of
< 0.05 values was selected to indicate statistical significance.
Among-group (localities) variation was examined using
an ANOVA on the 18 morphological characters, followed by
a Mann–Whitney (Ryan 1959) pairwise comparison using
Bonferroni-corrected P-values (Ury 1976). To best explain the
variation of the data, a principal component analysis (PCA)
was performed comparing all the species included in the study.
In addition, a discriminant function analysis (DFA) was used
to produce a scatter plot of specimens along the 1st and 2nd
axes producing maximal and 2nd to maximal separation among
all groups derived from multigroup discriminant function. All
variable loadings are expressed as a product of correlation
coefficients of the extracted components of canonical variates
with the log-transformed cranial measurements. Statistical tests
were evaluated at α = 0.05 and were performed using PAST
(Hammer et al. 2001) or R software version 3.2.1 (R Core Team
2014).
results
Karyotypic data.—A single karyotype (Fig. 2) was obtained
from an individual collected at Zitácuaro, Michoacán.
Additional karyotypes from closely related species and
Fig. 2.—Karyogram of an individual from Zitácuaro, Michoacán
(TTU104808). Chromosome presentation and numbering follows
that presented in Committee for Standardization of Chromosomes of
Peromyscus (1977). An asterisk (*) indicates chromosomes that are
biarmed.
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BRADLEY ET AL.—A CRYPTIC SPECIES OF PEROMYSCUS 5
populations from nearby geographic localities were examined
for comparison (Table 1). The karyotype of the specimen from
Zitácuaro, Michoacán (TK150644), possesses a diploid num-
ber (2n = 48) and fundamental number (FN = 56) similar to
that reported for specimens from Los Azufres and Pátzcuaro,
Michoacán, by Houseal et al. (1987). This karyotype contained
2 large pairs of biarmed, 1 medium pair of biarmed, and 2 small
pairs of biarmed chromosomes.
Sequence data.—Sequences from 8 individuals representing
the new species were combined with 28 samples representing
members of the P. boylii species group, other closely related
species groups, and the outgroup taxon. In all analyses (par-
simony, likelihood, and Bayesian), the P. boylii species group
as defined by Tiemann-Boege et al. (2000) and Bradley et al.
(2004, 2014) was retrieved as monophyletic. Relationships of
some taxa included as reference samples were peripheral to this
study and are not discussed in detail.
The Bayesian inference analysis produced a topology (Fig. 3)
in which the 8 individuals, representing the undescribed taxon
(samples from Michoacán and Morelos), formed a strongly
supported clade (clade probability value, CPV = 1.00).
This clade, in turn, was sister to a clade containing 5 repre-
sentatives of P. beatae (CPV = 1.00). The sister relationship
between the new species and P. beatae was strongly sup-
ported (CPV = 0.95). The clade containing P. species novum
and P. beatae then joined with samples of carletoni, levipes,
schmidlyi, and samples representing an additional unrecog-
nized taxon (reported as Peromyscus sp.) to form a large, well-
supported clade (CPV = 1.00). Samples of boylii, madrensis,
simulus, and stephani were added in a stepwise fashion to form
a monophyletic P. boylii species group (CPV = 1.00).
The parsimony analysis generated 10 equally most-parsi-
monious trees (length = 651). A majority rule consensus tree
was generated (not shown) that was similar in topology to the
tree obtained in the Bayesian analysis. BS support values were
obtained and superimposed onto Fig. 3. In this analysis, the 7
samples from Michoácan and the single sample from Morelos
formed a strongly supported monophyletic clade (BS = 97).
This clade was sister (BS = 78) to a clade containing the repre-
sentatives of P. beatae. Strong support was obtained (BS = 97)
for a sister relationship between the clade containing the new
species and P. beatae and a clade (BS = 92) containing sam-
ples of P. carletoni, P. levipes, P. schmidly, and 2 presumably,
undescribed Peromyscus from Michoácan. This large clade was
sister (BS = 94) to a clade containing the remaining members
of the P. boylii species group (boylii, madrensis, simulus, and
stephani).
The genetic divergence values (Table 2), estimated using
the Kimura 2-parameter model of evolution (Kimura 1980),
among samples representing the new species averaged 1.48%.
Collectively, these samples differed from their closest rela-
tives (determined in this study), P. beatae, P. carletoni, P. levi-
pes, and P. schmidlyi, by 5.31%, 5.16%, 5.38%, and 5.57%,
respectively. Genetic divergence values between other closely
related species in the P. boylii species group ranged from 3.25%
(P. levipes and P. schmidlyi) to 8.50% (P. boylii and P. levipes).
The undescribed taxon differs from P. levipes, to which it was
considered conspecific, by a genetic divergence value of 5.38%.
Morphometric data.—Means, ranges, and SEs for the 18
cranial measurements for all species in the P. boylii group are
presented in Table 3. Perusal of the data reveals that the unde-
scribed taxon, compared to the other taxa, is smaller than levi-
pes, beatae, and P. sp1 in most of the cranial measurements,
whereas it averages larger or about similar in measurements
compared with simulus, schmidlyi, boylii, and carletoni (see
“Comparisons” for more details).
ANOVA for the 18 measurements revealed statistically
significant differences (P < 0.05) among the taxa in each of
the measurements. However, a Shapiro–Wilk normality test
revealed that only 4 of the cranial measurements (LN, PPL, ZB,
and LBP) were normally distributed. Application of the non-
parametric Kruskal–Wallis test to indicate differences among
groups after correction for non-normality revealed significant
differences in only 7 measurements (LN, PPL, LIW, LMR,
LAB, RB, and BAM).
Both the Mann–Withney and Kruskal–Wallis tests, with
Bonferroni corrections, were used to assess pairwise compari-
sons between the undescribed taxon and the other taxa for the
18 cranial measurements. The results reveal several cranial
measurements that are significantly different between the unde-
scribed taxon and the other taxa (see “Comparisons” for more
detail). However, there is no single cranial measurement that
will distinguish the undescribed taxon from all other taxa in the
P. boylii species group.
The multivariate analyses confirmed the close morphological
similarity among the taxa. The 1st 3 components in the PCA
accounted for 63% of the total variation (PC1 35%, PC2 17%,
PC3 8%). The character loadings were all positive for the 1st
component with the 5 highest being LMF, LMR, LR, LN, and
LAB, respectively. For component II, all of the loadings were
positive except for 4 negative ones (LR, LAB, DB, and LMF).
The scatter plot for the 1st 2 components (not shown) revealed
extensive overlap among specimens from all the taxa except for
P. schmidlyi which overlapped with P. carletoni but none of the
other taxa. The new undescribed taxon was overlapped in the
scatter plot by all of the taxa except for P. schmidlyi.
The DFA (see Fig. 4) revealed a similar pattern with indi-
viduals of the undescribed taxon overlapping by all the other
taxa except for individuals of P. schmidlyi. The loadings for
DF1 were all negative except for 2 (MB and LIF) and the high-
est loadings were for LMF, LAB, and LR. DF2 had a mixture
of positive and negative loadings with fewer positive high load-
ings (LMF, LN) than negative high loadings (LMR, LBP, LIF,
LR, and LIW).
The classification analysis, associated with the DFA, reveals
only 2 taxa (P. schmidlyi and P. simulus) for which all of the
individuals are correctly classified; 91% (29 of 32) of the
P. beatae specimens were correctly identified. For P. carletoni
and P. boylii, the percent correctly classified was 76 (41 of 54
individuals) and 66% (29 of 44 individuals), respectively. Only
73% of the individuals representing the undescribed taxon were
correctly classified (40 out of 55); of the 15 misclassifications,
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6 JOURNAL OF MAMMALOGY
Fig. 3.—Phylogenetic tree generated using Bayesian methods (MrBayes—Huelsenbeck and Ronquist 2001) and the HKY+I+G model of evolu-
tion. Clade probability values (≥ 0.95) are indicated by an asterisk (*) and are shown above branches, bootstrap support values (≥ 70) obtained
from the parsimony analysis are below branches.
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BRADLEY ET AL.—A CRYPTIC SPECIES OF PEROMYSCUS 7
2 were identified as P. beatae, 5 as boylii, 6 as levipes, and 2 as
P. sp1. Among the taxa, 16 levipes were incorrectly classified as
the undescribed taxon, as were 5 boylii and 2 carletoni.
discussion
Together, results from karyotypic data, DNA sequence data,
and patterns of geographic distribution suggest that populations
(historically referred to P. levipes) from Michoácan, Morelos,
and presumably Estado de México represent an undescribed
species of Peromyscus. Below, these populations are formally
described as a new species.
Peromyscus kilpatricki, new species
Holotype.—Museum of Texas Tech University MoTTU
(TTU104808); adult male; skin, skull, and skeleton. Original
number Steve R. Hoofer 1179; TK150644 identifies tissue
samples deposited in Natural Sciences Research Laboratory,
MoTTU.
Type locality.—México: Michoácan; 13.5 km SW Zitácuaro
(UTM 14Q-352122-2140934); collected 25 July 2006.
Paratype.—One female (TTU104799, TK150627) deposited
in the Museum of Texas Tech University.
Diagnosis.—A species of Peromyscus with the following
characters: size medium for the genus; tail slightly longer
than head and body; hind foot medium; ear medium; dorsal
coloration dark (Sepia at tips, Blackish Slate at base; color
nomenclature following Ridgway [1912]); sides Dresden
Brown; venter pelage White at tips, Blackish Slate at base;
feet with Clove Brown strip extending slightly past ankle;
toes White; tail slightly bicolored, Clove Brown above and
White below, scantily haired at base and tufted at tip; ears
Dark Mouse Gray; vibrissae Black; skull elongate, twice as
long as wide; braincase slightly rounded; NL 114.6% of RL
and RL 35% of greatest skull length; molar tooth row about
14% of skull length; interorbital constriction a smooth out-
line, not angular; zygomatic arches nearly parallel; auditory
bullae medium; karyotype with 2n = 48 and 5 pairs of biarmed
chromosomes.
Distribution.—Occurs in the high-elevation mesic, mon-
tane, pine-oak forests of the Sierra Madre del Sur in central
Michoácan eastward to Morelos. Although undocumented
at this time, this species presumably occurs in the montane
regions of Estado de México, because they form part of the
same mountain ranges. Additional collecting efforts are needed
to better refine the distribution of this taxon.
Measurements.—External measurements of the holotype as
taken in the field (in mm) are: total length, 205; tail length, 106;
hindfoot, 22; and ear, 21. Cranial measurements were obtained
using dial calipers (in mm), accurate at 0.5 mm, and are as fol-
low: GLS, 27.7; LAB, 4.8; PPL, 9.4; LMF, 4.5; PL, 4.5; LIF,
5.6; LMT, 4.0; ZB, 13.5; MB, 11.5; GBM, 5.7; PPB, 4.3; WMF,
3.4; DB, 9.2; BB, 13.0; LIW, 4.4; RB, 4.8; NL, 11.0; and RL,
9.6. Mean measurements, ranges, and SEs for additional speci-
mens are presented in Table 3.
Comparisons.—A species in the P. boylii species group,
resembling the other 7 species in external and cranial size and
coloration, however, distribution (allopatric), karyotype, and
DNA sequence divergence (Cytb gene) preclude confusion.
The cryptic nature of the various species in the P. boylii group
is confirmed by the morphological analysis.
External measurements average smaller in P. kilpatricki
compared to P. beatae, P. levipes, and P. sp1. Compared to
P. boylii, kilpatricki is similar in the total length and tail length,
is slightly smaller in body and ear length, but larger in hind foot
length. Relative to P. carletoni, kilpatricki has smaller total and
hind foot lengths but has larger tail, body, and ear lengths; from
P. simulus, it is larger in total, tail, and ear lengths but smaller
in body and hind foot lengths; from P. schmidlyi, it is larger in
total, hind foot, and ear lengths but smaller in total and body
lengths.
In cranial measurements, compared to P. beatae, kilpatricki
averages smaller or similar in all measurements but LBP; from
P. levipes, it is decidedly smaller in all measurements except
WMF; from P. boylii, it averages larger, or about the same in all
measurements except 3 (LR, LN, and LAB); from P. carletoni,
it averages about the same in 5 measurements (ZB, LIW, RB,
PPB, and WMF), is smaller in 4 (LN, PPL, MB, and LIF), and
larger in the other 9; from P. simulus, it averages similar in 4
measurements (PPL, LAB, RB, and PPB), is smaller in 2 (ZB
and RB), and larger in the other 13; from P. sp1, kilpatricki
averages similar in 3 measurements (LBP, PPB, and WMF) and
is smaller in the other 15.
Table 2.—Average genetic distances estimated using the Kimura
2-parameter model of evolution (Kimura 1980) for selected compari-
sons of taxa of Peromyscus.
Comparison Average genetic
distance
Within species
P. beatae 1.24%
P. boylii 0.56%a
P. levipes 0.96%
P. schmidlyi 0.87%a
P. carletoni 0.65%b
P. new species 1.48%
Between P. species novum and closely related
species in the P. boylii species group
P. new species–P. beatae 5.31%
P. new species–P. boylii 8.09%
P. new species–P. carletoni 5.16%
P. new species–P. levipes 5.38%
P. new species–P. schmidlyi 5.57%
Between selected species in the P. boylii species group
P. beatae–P. boylii 8.31%
P. beatae–P. levipes 5.65%
P. beatae–P. schmidlyi 5.63%
P. boylii–P. levipes 8.50%
P. boylii–P. schmidlyi 7.94%
P. carletoni–P. levipes 3.50%
P. carletoni–P. schmidlyi 3.40%
P. levipes–P. schmidlyi 3.25%
aValues obtained from Bradley et al. (2004).
bValues obtained from Bradley et al. (2014).
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8 JOURNAL OF MAMMALOGY
Table 3.—Summary of univariate statistics for Peromyscus samples.
P. new species (n = 55) P. beatae (n = 32) P. boylii (n = 44)
Mean Range SE Mean Range SE Mean Range SE
Greatest length of skull 27.24 26.05–29.00 0.094 28.37 27.35–29.75 0.59 27.10 25.80–28.35 0.76
Length of rostrum 10.94 10.20–12.20 0.054 11.85 10.10–12.75 0.44 11.01 9.80–12.20 0.51
Length of nasal 9.81 8.77–11.66 0.072 10.61 9.98–11.48 0.38 9.89 8.86–11.20 0.58
Postpalatal length 9.07 8.20–10.00 0.054 9.46 8.80–10.45 0.38 9.08 8.40–9.70 0.37
Zygomatic breadth 13.64 12.80–10.00 0.059 14.18 13.60–15.30 0.38 13.32 12.30–14.95 0.53
Breadth of braincase 12.70 11.80–14.45 0.054 12.87 12.40–13.60 0.27 12.46 11.75–13.35 0.32
Mastoid breadth 11.64 10.95–12.60 0.046 12.04 11.55–12.75 0.28 11.62 11.15–12.50 0.29
Least interorbital width 4.32 3.95–4.70 0.022 4.42 4.20–4.70 0.13 4.32 4.00–4.60 0.15
Length of molar row 4.42 4.00–5.23 0.025 4.41 3.95–4.67 0.14 4.19 3.73–5.38 0.30
Length of incisive foramen 5.14 4.55–5.80 0.038 5.55 5.15–6.10 0.22 4.94 4.15–5.65 0.39
Length of auditory bulla 5.22 4.75–5.88 0.027 5.53 5.13–5.88 0.19 5.30 4.95–5.69 0.18
Depth of braincase 9.74 9.20–10.60 0.036 10.06 9.60–10.45 0.21 9.68 9.10–10.25 0.31
Length of mesopterygoid fossa 4.85 4.40–5.50 0.033 4.90 4.30–5.40 0.24 4.62 4.00–5.20 0.27
Length of bony palate 4.41 3.65–4.95 0.035 4.23 3.90–4.85 0.20 4.20 3.75–4.70 0.22
Rostral breadth 4.59 4.15–5.15 0.029 4.59 4.20–4.90 0.19 4.55 4.20–4.90 0.19
Breadth across molars 5.40 5.10–5.70 0.021 5.57 5.30–6.00 0.17 5.30 4.45–5.70 0.23
Postdental palatal breadth 3.97 3.60–4.50 0.024 4.11 3.70–4.50 0.20 3.97 3.20–4.35 0.22
Width of mesopterygoid fossa 2.38 2.00–2.85 0.020 2.46 2.20–2.70 0.13 2.33 2.10–4.35 0.15
P. carletoni (n = 54) P. levipes (n = 85) P. schmidlyi (n = 9)
Mean Range SE Mean Range SE Mean Range SE
Greatest length of skull 27.15 25.40–28.70 0.10 28.20 25.20–31.15 0.96 26.80 26.30–27.80 0.49
Length of rostrum 10.32 9.00–12.00 0.13 11.37 10.14–13.00 0.57 10.58 9.70–11.30 0.48
Length of nasal 10.44 8.86–11.70 0.10 10.34 8.86–12.65 0.63 9.01 8.40–9.60 0.43
Postpalatal length 9.28 8.40–10.00 0.06 9.58 8.60–11.10 0.48 8.98 8.60–9.40 0.27
Zygomatic breadth 13.66 12.70–14.60 0.05 14.20 13.05–15.60 0.48 13.28 12.60–13.80 0.38
Breadth of braincase 12.57 11.80–13.80 0.04 12.97 12.20–13.85 0.39 12.61 12.40–12.80 0.13
Mastoid breadth 11.85 11.00–12.60 0.06 11.95 11.10–13.15 0.38 12.10 11.70–12.40 0.24
Least interorbital width 4.37 4.00–4.70 0.02 4.45 4.05–4.95 0.18 4.53 4.40–4.80 0.14
Length of molar row 4.15 3.73–4.60 0.03 4.51 3.92–5.13 0.24 4.14 4.00–4.40 0.14
Length of incisive foramen 5.32 4.70–5.90 0.04 5.34 4.35–6.05 0.33 5.54 5.20–5.90 0.25
Length of auditory bulla 4.95 3.90–5.69 0.06 5.39 4.67–5.97 0.24 4.57 4.10–4.90 0.23
Depth of braincase 9.66 9.30–10.20 0.03 9.79 5.40–10.60 0.59 9.37 8.70–9.90 0.39
Length of mesopterygoid fossa 4.35 3.80–4.90 0.04 4.95 4.10–5.90 0.33 3.82 3.50–4.20 0.20
Length of bony palate 4.25 3.70–4.80 0.03 4.44 3.90–5.25 0.26 4.39 4.00–4.70 0.19
Rostral breadth 4.58 4.05–5.20 0.04 4.75 4.30–5.40 0.23 4.47 4.10–4.80 0.25
Breadth across molars 5.34 3.80–5.80 0.04 5.54 5.05–6.40 0.24 5.26 5.10–5.50 0.13
Postdental palatal breadth 3.96 3.30–4.80 0.04 4.07 3.55–4.50 0.23 3.93 3.80–4.20 0.15
Width of mesopterygoid fossa 2.35 1.90–2.80 0.03 2.36 2.05–2.70 0.12 2.48 2.30–2.70 0.16
P. simulus (n = 15) P. sp1 (n = 10)
Mean Range SE Mean Range SE
Greatest length of skull 27.12 25.30–28.40 0.78 28.37 27.75–29.50 0.18
Length of rostrum 10.73 10.00–11.40 0.41 11.64 10.75–12.35 0.14
Length of nasal 9.47 8.40–10.30 0.50 10.67 9.70–11.85 0.20
Postpalatal length 9.08 8.00–9.60 0.39 9.61 9.20–10.10 0.10
Zygomatic breadth 13.89 13.20–14.50 0.41 14.37 13.65–15.35 0.14
Breadth of braincase 12.35 11.10–11.80 0.24 13.02 12.45–13.60 0.11
Mastaoid breadth 11.46 3.90–4.40 0.20 12.11 11.25–13.00 0.14
Least interorbital width 4.18 3.60–4.20 0.14 4.38 4.10–4.90 0.06
Length of molar row 3.83 4.50–5.50 0.16 4.62 4.29–4.85 0.06
Length of incisive foramen 5.03 5.20–5.90 0.30 5.47 5.15–5.90 0.07
Length of auditory bulla 5.17 4.10–4.90 0.13 5.49 5.23–5.69 0.05
Depth of braincase 9.47 8.70–9.90 0.22 10.04 9.60–10.45 0.08
Length of mesopterygoid fossa 4.80 3.50–4.20 0.24 5.02 4.80–5.25 0.05
Length of bony palate 4.02 3.70–4.40 0.21 4.43 4.10–4.90 0.06
Rostral breadth 4.77 4.50–5.00 0.15 4.80 4.55–5.40 0.08
Breadth across molars 5.31 4.70–5.90 0.28 5.63 5.40–6.00 0.07
Postdental palatal breadth 3.95 3.70–4.30 0.15 3.94 3.75–4.30 0.05
Width of mesopterygoid fossa 2.32 2.10–2.50 0.10 2.35 2.20–2.50 0.03
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BRADLEY ET AL.—A CRYPTIC SPECIES OF PEROMYSCUS 9
The results of the pairwise comparisons, using Mann–
Withney and Kruskal–Wallis tests, revealed that P. kilpatricki
is significantly smaller (P < 0.05) than P. levipes in 13 of the
measurements (all except for DB, LMF, LBP, PPB, and WMF),
in 12 of the 18 measurements from P. beatae (all except for
BB, LIW, LMR, LMF, RB, and WMF), and 11 of the measure-
ments for P. sp1 (all except for BB, DB, LMF, LBP, RB, PPB,
and WMF). Compared to P. boylii, P. kilpatricki was signifi-
cantly larger in 4 measurements (LMR, LMF, ZB, and BB) and
smaller in only 1 (LN); from P. carletoni, it was significantly
larger in 4 (LMR, LMF, LR, and LAB) and smaller in 1 (LN);
from P. simulus, it was significantly larger in 3 (BB, LMR, and
LBP) but not significantly smaller in any of the measurements;
from P. schmidlyi, it was significantly larger in 4 measurements
(LAB, LMF, LN, and LMR) but smaller in 3 others (MB, LIW,
and LIF).
Peromyscus kilpatricki is most distinct from P. schmidlyi,
particularly in the multivariate analyses. In the univariate analy-
sis of cranial measurements, the 2 species are similar for 2 mea-
surements (LBP and PPB), smaller in 5 (LN, MB, LIW, LIF,
and WMF), and larger in the other 11 measurements. Especially
noteworthy is the relatively shorter but wider mesopterygoid
fossa, smaller auditory bullae, and relatively larger braincase in
kilpatricki compared to schmidlyi.
Peromyscus kilpatricki differs genetically, based on Cytb
sequences, from other members of the P. boylii species group
(P. beatae, P. boylii, P. carletoni, P. levipes, P. madrensis,
P. schmidlyi, P. simulus, and P. stephani) by 5.31%, 8.09%,
5.16%, 5.38%, 7.22%, 5.57%, 7.41%, and 8.17% sequence
divergence, respectively. The sister taxon of P. kilpatrick
appears to be P. beatae.
Peromyscus kilpatricki differs from other members of
the genus Peromyscus and the P. boylii species group by the
karyotype with a diploid number of (2n) 56. The karyotype
has 5 pairs of biarmed chromosomes that are similar in size
and morphology to those reported by Houseal et al. (1987) for
populations in Pátzcuaro and Los Azufres, Michoácan. This
karyotype is distinguishable from the FN = 52 forms (P. boylii
and P. simulus), FN = 52–54 forms (P. beatae), FN = 54 forms
(P. madrensis), by the presence of additional biarmed chromo-
somes, and differs from P. carletoni by having fewer biarmed
chromosomes (Table 2). Although the karyotype of P. kilpat-
ricki is similar to the FN = 54–56 forms (P. schmidlyi), and
FN = 56–60 forms (P. levipes), genetic differentiation in DNA
sequences suggests they represent different taxa.
Etymology.—This species is named in honor of Dr.
C. William Kilpatrick (Zadock Thompson Museum of Natural
History, University of Vermont) for his many contributions to
the systematic studies of the P. boylii species group and overall
passion for rodent systematics and taxonomy.
Nomenclatural statement.—A life science identi-
fier (LSID) number was obtained for the new species
Peromyscus kilpatricki: urn:lsid:zoobank.org:pub:D6B494C4-
1608-472F-9087-FEEBD35D7240.
Habitat.—Found in mesic pine-oak forest (Quercus spp. and
Pinus spp.) habitat at elevations greater than 1,600 m. Typically
associated with rock outcroppings, fallen logs, and moist soils.
Collected sympatrically with Baiomys taylori, Liomys pictus,
Osgoodomys banderanus, and P. spicilegus at the type locality.
Remarks.—The cryptic nature of the various species in the
P. boylii group is confirmed by the morphological analysis.
There are no cranial measurements that uniquely distinguish
P. kilpatricki from the other taxa in the species group. There is
overlap in cranial measurements between kilpatricki and all of
the other species. The results of pairwise comparisons between
kilpatricki and the other species indicate that kilpatricki is
Fig. 4.—Plots of the 1st 2 discriminant function axes extracted from a discriminant function analysis of 8 taxa of Peromyscus. This analysis was
performed on specimens with complete craniodental measurements. Polygons enclose maximal dispersion of individual specimen scores around
centroids for each taxa.
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10 JOURNAL OF MAMMALOGY
significantly smaller than beatae, levipes, and P. sp1 in most
cranial measurements and that it is not significantly larger
than these taxa in any cranial measurement. P. kilpatricki is
significantly larger than P. boylii, P. carletoni, P. simulus, and
P. schmidlyi in several (3 or 4) but not most of the cranial mea-
surements. Both the PCA and DFA (with classification analysis)
confirm these results. P. kilpatricki is broadly included within
the character space of all of the other taxa except P. schmid-
lyi. Only 73% of the specimens of kilpatricki were correctly
identified in the classification analysis. It appears that despite
being significantly different from some of the other taxa in a
few univariate comparisons, when variation across all morpho-
metric characters is considered (multivariate analyses) these
significant differences are overridden by the total morphologi-
cal variation. The only reliable way to identify with certainty
specimens of kilpatricki is to rely on chromosomal or molecu-
lar genetic characters.
acknowledgMents
We thank M. S. Corley, L. L. Lindsey, M. R. Mauldin, E. K.
Roberts, and C. W. Thompson for reviewing earlier versions
of this manuscript. Special thanks to V. J. Swier and C. W.
Thompson for karyotyping specimens. Tissue samples were
provided by the Natural Science Research Laboratory, Museum
of Texas Tech University, Zadock-Thompson Natural History
Collection, University of Vermont, and Monte L. Bean Life
Science Museum, Brigham Young University. Collecting per-
mits were provided by SEMARNAT. Special thanks to the Field
Methods classes of 2006 and 2008 for assistance in collecting
specimens. Partial support for this research was provided by a
NIH Grant (DHHS A141435-01 to RDB).
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Submitted 24 July 2016. Accepted 20 September 2016.
Associate Editor was Ricardo Moratelli.
appendix i
Specimens examined in the DNA sequencing portion of this
study. For each specimen, the collection locality, museum cata-
log number (abbreviations for museum acronyms follow Hafner
et al. [1997]), and GenBank accession number are provided in
parentheses. Abbreviations are as follows: Monte L. Bean Life
Science Museum (BYU), Museum of Texas Tech University
(TTU), Texas Cooperative Wildlife Collection (TCWC),
Universidad Nacional Autónoma de México (UNAM), University
of Michigan, Museum of Zoology (UMMZ), and Smithsonian’s
National Museum of Natural History (USNM). If museum cata-
log numbers were unavailable, specimens were referenced with
the corresponding TK number (special number of the Museum
of Texas Tech University). GenBank sequences not generated
in this study and were deposited by Bradley et al. (2000, 2004,
2007), Sullivan et al. (1997), and Tiemann-Boege et al. (2000).
Localities corresponding to Fig. 1 are provided (in parentheses)
only for select members of the P. boylii species group.
Peromyscus aztecus.—MEXICO: Veracruz; 8.8 km N
Huatusco (TCWC47976, U89968).
Peromyscus beatae.—GUATEMALA: Huehuetenango; 10
km NW Sta. Eulalia (Locality 24; ROM98290, AF131919).
HONDURAS: Francisco Morazán; 3.2 km NE El Hatillo
(Locality 25; TCWC52288, AF131914). MEXICO: Guerrero;
6.4 km SW Filo de Caballo (Locality 22; TCWC45222,
AF131922). Oaxaca; 6.4 km E Juquila (Locality 23; TCWC
45324, AF131920). Veracruz; Xometla (Locality 21;
TCWC48060, AF131921).
Peromyscus boylii.—MEXICO: Jalisco; 2 km NW El
Mesconcitos (Locality 10; TTU82688, AY322504); Sonora; Isla
San Pedro Nolasco (Locality 2; UMMZ117347, AF155387).
Peromyscus carletoni.—MEXICO: Nayarit; Ocota de
la Sierra, 21°50′N, 104°13′W (Locality 8; TCWC45206,
KF201659); 70 km N Santa María del Oro, UTM 13Q-559922-
2395306 (Locality 9; TTU110122, KF201662).
Peromyscus evides.—MEXICO: Guerrero; 6.4 km SSW Filo
de Caballo (TTU82696, FJ214685).
Peromyscus gratus.—MEXICO: Michoacán; Las Minas, 3
km SW Tuxpan (Cat. No. TK47810, KF201656).
Peromyscus hylocetes.—MEXICO: Michoacán; Estación
Cerro Burro, Microondas; 3,270 m (UNAM—catalog number
unavailable TK45309, DQ000481).
Peromyscus levipes.—MEXICO: México; 12 km S Acambay
(Locality 12; TTU82707, AY322509); 14.1 km NW Villa del
Carbon (Locality 13; TTU90321, KX523178). Nuevo León; Cola
de Caballo (Locality 4; TCWC47956, AF131928); Tlaxcala; 2
km W Teacalco, 2,710 m (Locality 20; TCWC48331, AF131929).
Peromyscus madrensis.—MEXICO: Nayarit; Isla María
Madre (Locality 7; USNM512599, AF155397).
Peromyscus kilpatricki.—MEXICO: Michoacán; km marker
81 between Ario de Rosales and La Huacana, 1,602 m,
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19°10′59″N, 101°43′42″W (Locality 16, catalog number not
available—TK47887, KX523179; catalog number not avail-
able—TK47890, KX523180; catalog number not available—
TK47897, KX523181); Las Minas, 3 km SW Tuxpan (Locality
17, catalog number not available—TK47819, DQ000477;
catalog number not available—TK47807, KX523182); 13.5
km SW Zitácuaro, UTM 14Q-352122-2140934 (Locality 18;
TTU104808, KF201672; TTU104799, KX523183). Morelos;
Cuernavaca, 18°59.142′N, 99°14.130′W, 2,210 (Locality 19;
BYU20730, KX523184).
Peromyscus oaxacensis.—GUATEMALA: Alta Verapaz,
Yalijux Mountain, Chelemha Reserve, 15°23′09″N,
90°03′44″W, 2,090 m (USNM569872, KF201657).
Peromyscus sp1.—MEXICO: Michoacán; 11.8 km WSW
Dos Aguas (Locality 14; TCWC45304, AF155409); 3 km NW
Aguilla, 780 m, 18°46.238′N, 102°45.747′W (Locality 15;
catalog number not available—TK45857, KX523185); 3.5
km S, 4.8 km E Zinapécuaro, 14Q-311971-2194257, 2,012 m
(Locality 11; TTU110119, KF201673).
Peromyscus schmidlyi.—MEXICO: Durango; 6.1 km W
Coyotes, UTM 13-465908E-2634281N (Locality 5; TTU81617,
AY370610); Sonora; 3 km E Yecura, Colegio Yecura (Locality
3; TTU110286, KF201658).
Peromyscus simulus.—MEXICO: Sinaloa; 6.4 km E
Concordia, Highway 40 (Locality 6; TCWC45592, AF131927).
Peromyscus spicilegus.—MEXICO: Durango; San Juan
de Camarones, UTM 13-356961E-2757448N (TTU81640,
AY322512).
Peromyscus stephani.—MEXICO: Sonora; Isla San Esteban
(Locality 1; UMMZ117385, AF155411).
Peromyscus winkelmanni.—MEXICO: Michoacán; 6.9 mi
WSW Dos Aguas (TCWC45621, AF131930).
Specimens examined in the karyotypic portion of this study.
Previously published karyotypes used as references are listed
in Table 1.
Peromyscus kilpatricki.—MEXICO: Michoacán; 13.5 km
SW Zitácuaro, UTM 14Q-352122-2140934 (Locality 18;
TTU104808, KF201672).
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