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A new species of Batomys (Mammalia: Muridae) from eastern Mindanao
Island, Philippines
Danilo S. Balete, Lawrence R. Heaney*, Eric A. Rickart, Roselyn S. Quidlat,and
Jason C. Ibanez
(DSB, LRH) Field Museum of Natural History, 1400 S Lake Shore Drive, Chicago, Illinois
60605, U.S.A., e-mail: heaney@fieldmuseum.org;
(EAR) Utah Museum of Natural History, University of Utah, 1390 E Presidents Circle, Salt
Lake City, Utah 84112, U.S.A.;
(RSQ, JCI) Philippine Eagle Foundation, Inc. VAL Learning Village, Ruby St., Marfori
Heights, Davao City 8000, Philippines;
(DSB) Laksambuhay Conservation, Inc., 10241 Mt. Bulusan St., Umali Subd., Los Banos,
Laguna, Philippines
Abstract.—Murid rodents of the endemic genus Batomys are diverse and
geographically widely distributed in the Philippines. Four species have been
recognized: B. dentatus and B. granti on Luzon, B. salomonseni on several
islands comprising the Mindanao faunal region, and B. russatus on Dinagat
Island. A recent survey of small mammals in eastern Mindanao recorded the
presence of Batomys on Mt. Hamiguitan, the only other documented
occurrence of this genus on Mindanao Island outside of Mt. Kitanglad.
Comparison of external morphology as well as cranial and dental features of
the Hamiguitan Batomys with available specimens of congeners indicates
that although it is closely allied to B. salomonseni, a number of distinct traits
separate it from all its congeners, and we describe it as a new species, B.
hamiguitan. This species corroborates the hypothesis that the island of
Mindanao is comprised of multiple centers of endemism, of which the
southeastern highland of Mt. Hamiguitan is one.
The murid fauna of the Philippines
comprises a diverse assemblage of rodents
exhibiting a wide array of morphological
and ecological specializations, ranging
from 25 g reddish-brown, vermivorous
shrew-mice (Archboldomys spp.) to 2.6
kg black and white, folivorous cloud rats
(Phloeomys spp.). Of the 22 genera and 59
native species recognized to date, 15
genera (71%) and 53 species (95%) are
endemic to the Philippines (Heaney et al.
1998, Musser et al. 1998, Rickart et al.
1998, Heaney & Tabaranza 2003, 2005,
2006; Balete et al. 2006, 2007).
In a preliminary assessment of mor-
phological characters of these murid
rodents, Musser & Heaney (1992) out-
lined a hypothesis of their relationships in
a phylogenetic context, and organized the
fauna intro three major assemblages
(Divisions I–III) without implying mono-
phyly of each. The hairy-tailed rats of the
genus Batomys were treated as members
of Division I, the Old Endemics, an
assemblage that comprises a diverse
group of Philippine murids that exhibit
many basal features as well as distinctive
specializations. As originally erected, the
Old Endemics division consisted of ten
genera including Apomys, Archboldomys,
Batomys, Carpomys, Celaenomys, Chrot-
* Corresponding author.
PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
121(4):411–428. 2008.
omys, Crateromys, Crunomys, Phloeomys,
and Rhynchomys (recent reviews have
synonymized Celaenomys with Chrot-
omys; Corbet & Hill 1992, Musser &
Carleton 2005, Rickart et al. 2005).
Members of Division I were further
clustered into six proposed monophyletic
taxa, each defined in most respects by
apomorphies in cranial and dental mor-
phologies that reflect unique feeding
habits and living conditions. Batomys
was placed in the Crateromys group
together with Carpomys and Crateromys.
Musser et al. (1998) provided a compre-
hensive review of the genus and recog-
nized four species: B. dentatus from
northern Luzon, B. granti from northern
and southeastern Luzon, B. salomonseni
from the islands of Biliran, Dinagat,
Leyte, and Mindanao, and B. russatus
from Dinagat. They found B. granti and
B. salomonseni to be the most similar
morphologically but noted the need for
larger samples. In this paper, we report
larger samples of several of these species
but note that B. dentatus is still known
from a single specimen, and B. russatus
from only two.
The murid relationships proposed by
Musser & Heaney (1992) were strongly
supported by phylogenetic analyses uti-
lizing mitochondrial and nuclear genes
(Jansa et al. 2006). Jansa et al. (2006)
found strong support for an arboreal
murid clade encompassing the Crater-
omys group (as defined by Musser &
Heaney 1992) and Phloeomys.Theyalso
found that B. granti and B. salomonseni
are sister taxa but found no molecular
support for the monophyly of Batomys
with respect to Crateromys and recom-
mended further studies to clarify generic
limits.
A recent survey of the mammals on Mt.
Hamiguitan in southeastern Mindanao
produced the first records of Batomys
from that island east of the Kitanglad
Range, where B. salomonseni occurs
(Fig. 1; Heaney et al. 2006, Balete et al.
2008b). Our comparison of Batomys from
Mt. Hamiguitan with B. salomonseni from
Mt. Kitanglad uncovered many morpho-
logical similarities that imply close rela-
tionship but also revealed sufficient dif-
ferences to warrant the recognition of the
former as a distinct species.
Materials and Methods
For comparison with the new species,
we used specimens of B. granti from the
Central Cordillera of Luzon (from or
near the type locality) and of B. salomon-
seni from Mt. Kitanglad (the type local-
ity). Because Batomys dentatus is more
distantly related to B. granti and B.
salomonseni (Musser et al. 1998), we did
not include it in our comparisons. Be-
cause B. russatus occurs geographically
near Mindanao, we chose to include it in
many of our comparisons, even though it
is morphologically distinct from the
others.
Museum numbers and geographic
sources of specimens examined in this
study are listed in Appendix 1. They
include specimens collected by the au-
thors and their associates (Heaney et al.
2006, Balete et al. 2008b), as well as
specimens from earlier expeditions (San-
born 1952, 1953; Musser et al. 1998)
deposited at the Field Museum of Natural
History (FMNH). Specimens were as-
signed to age categories defined by
Musser & Heaney (1992), based on
relative body size, reproductive condition,
and molar tooth wear. Terminology for
external features of the head and limbs
follows Brown (1971) and Brown &
Yalden (1973). Terminology for cranial
and dental features follows Musser &
Heaney (1992). Scanning electron micro-
graphs of teeth were made from uncoated
specimens.
Measurements (mm) of total length,
length of tail (LT), length of hind foot
including claws (LHF), and length of ear
from notch (LE), and weight in grams
412 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
(WT) were taken from field catalogs of
the authors located at FMNH. The length
of head and body (LHB) was determined
by subtracting length of tail from total
length. Length of over-fur (LOF) was
measured in the mid-dorsal region. The
number of tail scale rings per centimeter
(TSR) was counted at a point on the tail
one-third of the total length from the
base.
Twenty-eight cranial and dental mea-
surements were taken from 18 adult
specimens of Batomys from Mindanao.
The following morphological terms and
the limits of their measurements are
defined and illustrated in Musser &
Heaney (1992): greatest length of skull
(GLS), interorbital breadth (IB), zygo-
matic breadth (ZB), breadth of braincase
(BBC), height of braincase (HBC), length
of nasal bones (LN), length of rostrum
(LR), breadth of rostrum (BR), breadth
of zygomatic plate (BZP), length of
diastema (LD), palatal length (PL),
Fig. 1. Map of Mindanao and adjacent islands showing some major topographic features and the
distribution of Batomys hamiguitan (Mount Hamiguitan), B. salomonseni (Kitanglad Range), and B. russatus
(Dinagat Island).
VOLUME 121, NUMBER 4 413
post-palatal length (PPL), length of inci-
sive foramina (LIF), breadth across
incisive foramina (BIF), distance from
posterior edge of incisive foramina to
anterior margin of first molars (IF–M
1
),
length of palatal bridge (LPB), palatal
breadth at first molars (PBM
1
), palatal
breadth at last molars (PBM
3
), breadth of
mesopterygoid fossa (BMF), length of
auditory bulla (LB), breadth across inci-
sor tips (BIT), crown length of maxillary
molar toothrow (LM
1–3
), crown length of
upper first molar (LM
1
), crown breadth
of upper first molar (BM
1
), length of
mandible plus lower incisor (LMI), pos-
terior height of mandible (HM), and
crown length of mandibular molar tooth-
row (LM
1–3
). Measurements were taken
by Balete and recorded to the nearest
0.1 mm using dial calipers.
We used SYSTAT 10 for Windows
(SPSS, Inc., 2000) for statistical analysis of
measurements. Descriptive statistics (mean,
standard deviation, and observed range)
were calculated for sample groups. Quanti-
tative phenetic variation was assessed
through principal components analysis (us-
ing the correlation matrix) of log
10
-trans-
formed measurements of adult specimens.
Stomach contents were analyzed in the
field for specimens prepared as skeletons
and in the laboratory for specimens
initially fixed in formalin and subsequent-
ly preserved in ethyl alcohol. Stomach
contents were scored for presence of
arthropod exoskeletons, plant matter,
and annelid worms. Results are presented
as percentage occurrence of each of the
three categories among the total number
of specimens examined of each species.
Reproductive autopsies were performed
in the field on specimens prepared as
skeletons or in the laboratory on fluid-
preserved specimens. For males, the testes
were scored for position (scrotal or ab-
dominal), size (length 3 width, in mm),
and relative convolution of the epididymis.
For females, data were taken on the size
and condition of teats (small, large, or
lactating), and the number and size (crown
to rump length, in mm) of embryos or
number of placental scars in the uterus.
The capture and handling of animals in
the field was conducted in accordance
with animal care and use guidelines
established by the American Society of
Mammalogists (Animal Care and Use
Committee 1998).
Results
Distinct differences are apparent in
adult body size and external proportions,
as well as in cranial and dental measure-
ments among the four groups of Batomys
that we examined (Tables 1, 2). Adults of
B. salomonseni exhibit some detectable
sexual dimorphism in external and cranial
measurements, but due to small sample
size, the sexes were pooled for the
comparisons that follow.
We conducted a principal components
analysis on a subset of 19 measurements
taken from 9 adult specimens of Batomys
having intact (or nearly intact) crania,
and complete external measurements.
These included B. salomonseni from
Bukidnon Province, Mindanao (n 5 4),
B. granti from Kalinga and Mountain
provinces, Luzon (n 5 3), and specimens
from Mt. Hamiguitan, Davao Oriental
Province, Mindanao (n 5 2). We excluded
B. russatus from this analysis because it is
easily distinguished metrically by its small
size (and by numerous morphological
features) and because we had only a
single skull for comparison. The first four
components accounted for 80.7% of the
total variance (Table 3). Most variables
had positive loadings of high magnitude
on component 1 (accounting for 42.6% of
the variance), indicating that much of the
variation involved size. Component 2
(accounting for 16.5% of the variation)
separated individuals primarily on the
basis of interorbital breadth, length of
palatal bridge, breadth of palate, and
length of mandibular tooth row. Compo-
414 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
nent 3 (12%) separated individuals based
primarily on the length and breadth of
incisive foramina, length of palatal
bridge, and length of tail, and component
4(9.6%) separated specimens based on
length of ear and size of auditory bulla
(Table 3). A bivariate plot of specimen
scores on components 1 and 2 (Fig. 2,
left) reveals that the Hamiguitan Batomys
is separated from B. granti on component
1, and partially separated from B. salo-
monseni on component 2. In a plot of
components 3 and 4 (Fig. 2, right), the
Hamiguitan Batomys is separated from
the other taxa on component 3.
On the basis of these results and the
diagnostic features detailed below, we recog-
nize the Batomys from Mt. Hamiguitan as
a new species that we describe as follows.
Batomys hamiguitan, new species
Figs. 3–5, Tables 1, 2
Holotype.—FMNH 190163, adult fe-
male, collected on 10 May 2006 (original
number of R. S. Quidlat 53; Fig. 3);
initially fixed in formalin, now preserved
in ethyl alcohol with skull removed. The
skull (Fig. 4) is in good condition, except
for a broken tip of the right nasal. A
sample of muscle tissue was removed
from the left thigh in the field; the
specimen is otherwise in good condition.
It is deposited at FMNH but will be
transferred to the National Museum of
the Philippines, Manila.
Type locality.—2.5 km S, 0.25 km E
Mount Hamiguitan peak, San Isidro
Municipality, Davao Oriental Province,
Mindanao Island, Philippines, 1128 m;
06u439030N, 126u11901.90E (Fig. 1; coor-
dinates taken with a GPS unit).
Distribution.—Known only from Mt.
Hamiguitan, where specimens were
trapped in disturbed transitional lowland
dipterocarp/lower montane forest at
950 m elevation, and in primary lower
montane forest at 1128 m elevation.
Referred specimens.—Along with the
holotype, six other specimens were cap-
Table 1.—External measurements (mm), body mass (g) and measurement ratios(%) of adult Batomys,
including a new species from Mt. Hamiguitan, eastern Mindanao. Measurements of sample size (n) greater
than 3 are given as mean 6 1 SD and their ranges; as average for sample sizes of 3 or less. Sample sizes less
than n are given in parentheses after the range. Variable abbreviations are defined in Materials and
Methods section.
Batomys hamiguitan Batomys granti
b
Batomys russatus
c
Batomys salomonseni
d
Holotype Total specimens
a
n 5 3 n 5 5 n 5 1 n 5 6
LHB 188 183 193 6 6.3 151 185 6 5.9
171–189 185–197 174–191
LT 125 119 161 6 13.6 – 137 6 8.4
111–125 149–180 (4) 130–150 (5)
LHF 35 35 37 6 2.4 30 37 6 1.9
35–36 33–39 34–39
EAR 25 23.5 22 6 0.8 18 23 6 1.4
22–25 21–23 21–24
WT 180 173 188 6 22.7 115 190 6 8.7
155–183 165–226 180–205
LOF 12–15 12–15 (2) 11–13 (1) 11–12 15–18 (3)
TSR 11 10–11 (2) 9 (1) 15 11–12
LT/HBL 66 63–66 76–90 – 68–81
LHF/HBL 19 18–21 17–20 20 19–20
a
FMNH 190163 (holotype), 190165, 190166.
b
FMNH 169126, 188321, 188323, 193689, 193691.
c
FMNH 189788.
d
FMNH 147927, 147929, 147931, 148164, 148171, 148172.
VOLUME 121, NUMBER 4 415
Table 2.—Cranial and dental measurements (mm) of adult Batomys. Measurements for sample sizes (n)
greater than 3 are given as the mean 6 1 SD and the range, or as only the mean and range for sample sizes of
3 or less. Sample sizes less than n 5 3 are given in parentheses after the range. Variable abbreviations are
defined in the Materials and Methods section.
Batomys hamiguitan Batomys granti
b
Batomys russatus
c
Batomys salomonseni
d
Holotype Total specimens
a
n 5 3 n 5 6 n 5 1 n 5 6
GLS 42.77 42.77 (1) 45.0 6 0.30 34.31 43.4 6 1.46
44.8–45.4 (4) 41.6–45.1 (4)
IB 6.46 6.3 6.1 6 0.35 5.45 6.4 6 0.21
6.21–6.46 5.6–6.5 6.0–6.6
ZB 22.08 22.08 (1) 22.4 6 0.88 18.9 22.3 6 0.68
21.5–23.4 (5) 21.6–23.1 (5)
BBC 17.15 17.15 (1) 16.8 6 0.31 14.28 16.6 6 0.52
16.4–17.1(4) 15.8–17.0 (5)
HBC 11.80 11.80 (1) 12.1 6 0.26 9.97 12.4 6 0.64
11.8–12.4 (4) 12.0–13.3 (4)
LN 17.61 17.1 18.4 6 0.41 12.93 17.8 6 0.82
16.34–17.61 17.8–18.8 16.7–18.9 (5)
LR 15.38 15.3 15.8 6 0.57 11.07 15.7 6 0.96
15.04–15.54 15.0–16.6 14.1–16.5 (5)
BR 8.29 8.1 8.7 6 0.20 7.16 8.4 6 0.59
7.95–8.29 8.4–8.9 7.7–9.0
BZP 4.20 4.3 4.4 6 0.15 3.45 4.5 6 0.24
4.20–4.40 4.2–4.6 4.2–4.8
BIT 2.57 2.4 2.4 6 0.17 2.09 2.7 6 0.10
2.29–2.57 2.2–2.5 (4) 2.5–2.8
LD 11.59 11.5 12.8 6 0.40 8.75 12.1 6 0.57
11.21–11.62 12.2–13.4 11.3–12.8
PL 19.97 19.7 21.5 6 0.32 15.12 20.6 6 0.55
19.47–19.97 (2) 21.0–21.9 20.1–21.6
PPL 15.20 15.20 (1) 17.1 6 0.43 13.02 15.8 6 0.63
16.8–17.8 (4) 14.8–16.2 (4)
LIF 8.96 8.2 8.6 6 0.33 5.49 7.9 6 0.39
7.17–8.96 8.4–9.3 7.2–8.3
BIF 3.22 3.1 3.1 6 0.32 2.53 2.9 6 0.33
2.98–3.22 2.6–3.5 2.5–3.5
IF–M
1
0 0 1.0 6 0.25 1.19 1.2 6 0.23
0.7–1.5 0.9–1.6
LPB 6.53 6.4 6.9 6 0.33 5.49 7.5 6 0.41
6.24–6.53 (2) 6.5–7.4 7.0–8.1
PBM
1
3.47 3.5 3.8 6 0.40 – 3.4 6 0.39
3.47–3.56 3.4–4.6 2.7–3.8
PBM
3
3.93 4.1 4.6 6 0.43 3.24 4.1 6 0.46
3.93–4.28 (2) 3.9–5.2 3.3–4.6
BMF 3.18 3.2 3.0 6 0.21 2.9 3.2 6 0.27
3.18–3.22 (2) 2.8–3.3 (5) 3.0–3.6 (5)
LB 5.41 5.3 5.6 6 0.25 3.96 5.2 6 0.19
5.23–5.41 (2) 5.3–5.9 (5) 5.0–5.5 (5)
HB 5.58 5.1 5.5 6 0.12 4.45 5.4 6 0.20
4.67–5.58 (2) 5.4–5.7 (5) 5.1–5.7 (5)
LM
1–3
8.18 8.0 7.8 6 0.33 – 8.0 6 0.16
7.73–8.18 7.3–8.2 7.7–8.2
LM
1
3.56 3.4 3.3 6 0.23 – 3.5 6 0.21
3.28–3.56 3.0–3.6 3.2–3.9
BM
1
2.21 2.2 2.3 6 0.10 – 2.3 6 0.08
2.21–2.32 2.2–2.4 2.2–2.4
416 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
tured at the type locality, including five
females deposited at the Field Museum
(FMNH 190161, 190162, 190164–
190166), and one male deposited at the
Central Mindanao University, Musuan,
Bukidnon Province. One additional fe-
male specimen (FMNH 186819) was
taken below the type locality, near a
small lake, Tinagong Dagat, 3.75 km S,
1.75 km E Mt. Hamiguitan peak, 950 m,
06u42926.20N, 126u11942.80E.
The six specimens deposited at the
Field Museum are preserved in ethyl
alcohol, five with skulls removed and
cleaned (FMNH 186819, 190161, 190164–
190166). Muscle tissue was removed from
the left thigh of each, and the stomach
was removed for analysis of contents.
Two specimens have broken crania and
mandibles (FMNH 190165, 190166), but
the others are in good condition.
Etymology.—The species is named af-
ter Mt. Hamiguitan, a mountainous
ultramafic outcrop and the main topo-
graphic feature of the Pujada Peninsula,
Eastern Mindanao (Balete et al. 2008b).
The specific epithet is used as a noun in
apposition. We propose ‘‘Hamiguitan
hairy-tailed rat’’ as the English common
name.
Batomys hamiguitan Batomys granti
b
Batomys russatus
c
Batomys salomonseni
d
Holotype Total specimens
a
n 5 3 n 5 6 n 5 1 n 5 6
LMI 28.13 27.6 29.8 6 0.78 22.2 28.9 6 1.03
26.97–28.13 (2) 29.2–31.4 27.7–30.1
HM 12.29 11.7 13.0 6 0.32 9.25 12.4 6 0.55
11.18–12.29 (2) 12.6–13.5 11.8–13.4
LM
1–3
7.89 7.8 8.3 6 0.32 – 8.0 6 0.17
7.78–7.89 8.0–8.7 7.8–8.2
a
FMNH 190163 (holotype), 190166.
b
FMNH 62503, 62504, 169126, 188321, 193689, 193691.
c
FMNH 189788.
d
FMNH 147927, 147929, 147931, 148164, 148171, 148172.
Table 2.—Continued.
Fig. 2. Results of principal components analysis of measurements of adult specimens of Batomys (see
Table 3): projections of specimen scores on components 1 and 2 (left) and on components 3 and 4 (right) for
B. granti (solid squares), B. salomonseni (open squares), and B. hamiguitan (crosses).
VOLUME 121, NUMBER 4 417
Diagnosis.—Batomys hamiguitan is dis-
tinguished from other members of the
genus by the following combination of
traits: 1) mystacial and superciliary vi-
brissae longer than in all congeners; 2) tail
absolutely and relatively shorter than in
B. granti or B. salomonseni, absolutely
longer but relatively shorter than in B.
russatus; 3) pelage shorter and coarser
than in B. salomonseni, longer and coarser
than in B. granti or B. russatus); 4) skull
shorter and broader than in B. granti or
B. salomonseni, longer and broader than
in B. russatus; 5) incisive foramina longer
(extending beyond anterior edge of first
maxillary molars) than in B. russatus or
B. salomonseni, shorter than in B. granti;
6) palate shorter than in B. granti or B.
salomonseni, longer than in B. russatus;7)
palatal bridge shorter and narrower than
in B. granti or B. salomonseni, longer and
wider than in B. russatus; 8) mandible
shorter and narrower than in either B.
granti or B. salomonseni, longer and
higher than in B. russatus; and 9) cusp
t9 of M3 consistently present and well
developed (usually absent in other spe-
cies, poorly developed when present).
Description and comparisons.—In gen-
eral body form Batomys hamiguitan is
most similar to B. salomonseni but differs
from it and other congeners in body size,
pelage color, and in various external,
cranial, and dental features (Tables 1, 2;
Figs. 3–5). The new species is of medium
body size, with length of head and body
that is only slightly shorter than in B.
granti or B. salomonseni (shortest in B.
russatus) but weighing less than either
(Table 1).
The dorsal pelage of B. hamiguitan
(Fig. 3) is yellowish-brown overall. It is
shorter and coarser than in B. salomon-
Table 3.—Character loadings, eigenvalues, and
percentage variance explained on the first four
components of a principal components analysis of
log-transformed measurements of adult Batomys
(see Fig. 2). Variable abbreviations are defined in
Materials and Methods.
Variable
Principal component
1234
LHB 0.752 20.401 0.170 20.248
LT 0.530 20.464 20.563 20.362
LHF 0.932 0.022 20.157 0.233
LE 20.458 0.144 0.046 20.758
IB 0.010 0.957 0.134 0.070
LN 0.954 20.015 0.164 0.190
LR 0.927 0.182 0.172 0.040
BR 0.973 0.133 20.042 0.003
BZP 0.316 0.087 20.086 0.176
LD 0.898 0.068 20.021 0.275
PL 0.922 20.042 20.260 0.003
LIF 0.403 20.414 0.744 20.242
BIF 0.188 20.083 0.655 0.380
LPB 0.415 0.588 20.682 0.074
PBM
3
0.430 20.658 20.034 0.174
BMF 0.455 0.453 0.332 20.111
LB 0.619 20.230 0.034 20.537
HB 0.673 0.274 20.131 20.453
LM
1–3
0.329 0.678 0.420 20.317
Eigenvalue 8.102 3.129 2.279 1.815
Variance
explained (%)
42.643 16.468 11.992 9.551
Fig. 3. Batomys hamiguitan (FMNH 190163,
holotype), adult female from Mt. Hamiguitan,
Davao Oriental Province, Mindanao. Photo taken
09 May 2006 by R. S. Quidlat.
418 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
seni (which has sleeker, dark chestnut-
brown fur) and is coarser but longer than
in B. granti (which has pale reddish-brown
fur), and in B. russatus (which has sleek
brownish-red fur). The guard hairs in B.
hamiguitan, 18–22 mm, are dark gray to
black, with the distal 3–4 mm pale yel-
lowish brown to unpigmented; they are
longer and mainly with unpigmented tips
on the rump region. The over-fur is 12–
15 mm, slate gray at the bases, with the
distal fifth pale yellowish-brown with
short black to grayish-brown tips. The
venter is grayish-buff overall, ca. 10–
12 mm, grading imperceptibly into the
dorsal color and without distinct demar-
cation between dorsum and venter. The
ventral pelage varies from grayish brown
to pale reddish-orange in B. salomonseni,
pale grayish-buff in B. granti, to ochrac-
eous in B. russatus, with irregular white
patches on the venter sometimes present in
the latter two species.
The skin around the eye is edged with a
narrow band (less than 1 mm) of darkly
pigmented skin, from which arises sparse,
short, dark hairs, especially on the lower
edge of the eye. This narrow, dark band is
immediately surrounded by a narrow ring
of pale skin. Long, fairly coarse, dark
brown hairs are sparse on the inner
portion of this pale ring but increase in
density at points increasingly peripheral
to the eye, gradually merging into the fur
that covers the head. In a live specimen
(Fig. 3), this pale ring was evident,
creating a partial mask-like effect that
became inconspicuous in the preserved
state. Among other species of Batomys,
the eye-ring of unpigmented naked skin is
persistent in preserved specimens,
brought about by the profusion of thick
and long dark fur immediately surround-
ing its edges, creating a characteristic
mask-like effect in B. granti and B.
salomonseni, which is not conspicuous in
B. russatus.
The ears of B. hamiguitan are smoothly
rounded and slightly longer than in its
congeners (Table 1), with the distal two-
thirds pigmented dark gray, paler on the
inside, covered with short dark and pale
brown fur interspersed with a sprink-
ling of unpigmented (translucent/white)
Fig. 4. Dorsal, ventral and lateral views of cranium and lateral view of mandible of the holotype of
Batomys hamiguitan (FMNH 190163).
VOLUME 121, NUMBER 4 419
strands. The basal third is unpigmented,
covered with a mix of long and soft
unpigmented and pale grayish brown fur
with unpigmented bases. The facial vi-
brissae are longest in B. hamiguitan,
extending well beyond ears and shoulders,
with the mystacial vibrissae reaching to
80 mm, superciliary to 70 mm, and genal
up 43 mm. In this respect, it is similar to
B. salomonseni and B. russatus in having
very long superciliary vibrissae (up to
45 mm in the former) that extend beyond
the margins of the pinna—a trait that
easily separates them from both B.
dentatus and B. granti on Luzon (Musser
et al. 1998).
The tail of B. hamiguitan is absolutely
shorter than in B. granti or B. salomonseni
(Table 1) but longer than in B. russatus
(see Table 4 in Musser et al. 1998). At
about 66% of combined head and body
length, the tail of B. hamiguitan is also
relatively shorter than in its congeners (up
to 85% in B. salomonseni (Table 1; also
see Table 4 in Musser et al. 1998). The tail
of B. hamiguitan is slender, pigmented
dark gray and covered with short hair.
The possession of a slender tail with short
hair suggests a close affinity of B.
hamiguitan with congeners in the Min-
danao Faunal Region, B. salomonseni and
B. russatus, in contrast to the robust and
hairy tail of B. dentatus and B. granti
from Luzon (Musser et al. 1998). The tail
of B. hamiguitan (Table 2) bears 10–11
scale rings/cm (TSR) and is most similar
to B. salomonseni (up to 12 TSR). Each
scale has three associated short hairs that
are dark brown in the basal half, paler on
the distal half with unpigmented tips. The
middle hair is longest, overlapping with
up to five scale rows, whereas outer hairs
only extend over three scale rows. In
contrast, B. granti has larger scale rings (9
TSR), and B. russatus has the finest (15
TSR).
The front feet of B. hamiguitan are
short with robust digits that are dorsally
unpigmented and covered with short,
white hairs and marked by a band of
grayish-brown fur tapering from the
wrists to about the bases of the inner
digits. The pollex bears a wide flat nail,
and other digits have claws that are short,
sharp, decurved, and opaque. The palmar
surface is pigmented pale gray, including
the base of palmar pads. The thenar and
hypothenar are large and fleshy, and
there are three interdigital pads, each
about a quarter of the size of the thenar.
On both front and hind feet, an ungual
tuft of white hairs sprouts from the base
of the opaque claws and extends to just
short of the claw tips, a pattern also
observed in B. russatus. In contrast, in
both B. granti and B. salomonseni, the
ungual tufts, also white, extend beyond
the claw tips of both front and hind feet.
The hind feet of B. hamiguitan are
absolutely shorter than in B. granti or B.
salomonseni (shortest in B. russatus), but
relative to HBL B. hamiguitan has the
shortest hind feet among its congeners
(Table 1). The dorsal surface of the hind
foot of B. hamiguitan has a narrow band
of medium grayish-brown fur that ex-
tends from the outer side of the leg near
the ankle to about the mid-dorsal meta-
tarsal area. The remainder is unpigment-
ed and covered with short hairs (usually
white but entirely pale grayish brown in
FMNH 190165). In B. salomonseni, the
entire dorsal skin surface of the hind foot
is pigmented pale to medium gray,
including the digits in some individuals
(FMNH 147929, 147928) and is covered
with a mix of medium brown and
unpigmented hairs. Both B. granti and
B. russatus have hind feet with unpig-
mented dorsal skin covered with a mix of
short, dark grayish-brown fur with un-
pigmented tips and entirely unpigmented
strands in the former, or with pale russet
markings except on the digits in the latter.
The plantar surface, including the
thenar, hypothenar and two outer digital
pads, is pigmented pale gray (slightly
darker on the elongate thenars). The
420 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
plantar pads are small relative to the
plantar surface. The hypothenar and
outer interdigital pads (1 and 4) are
similar in size, barely a third of the length
of thenar, whereas the two inner inter-
digitals (2 and 3) are slightly smaller. In
B. salomonseni, the plantar surface is pale
grayish-brown, darker on the thenar and
hypothenar, and the pads are larger
relative to the plantar surface, with a
hypothenar that is smaller than the two
outer interdigitals, and the other inter-
digitals similar to or larger than the
hypothenar. In B. russatus, the plantar
surface, including pads, is unpigmented,
whereas in B. granti the surface is
generally unpigmented, but the thenar
and hypothenar show dark to pale gray
spotting in some individuals.
The cranial and dental morphology of
B. hamiguitan (Figs. 4, 5) is similar to
congeners (see Thomas 1898, Sanborn
1953, Fig. 6, and illustrations in Musser
& Heaney 1992, Musser et al. 1998), but
B. hamiguitan exhibits several features
that are distinctive. The robust skull of
Batomys hamiguitan is most similar to
that of B. salomonseni in shape and
relative dimensions (compare Figs. 4 and
6) but slightly smaller and shorter,
whereas both species are smaller than B.
granti and larger than B. russatus (Ta-
ble 2). The rostrum of B. hamiguitan
(Table 2, Fig. 4) is absolutely shorter
and narrower than in B. granti or B.
salomonseni (shortest and narrowest in B.
russatus). The nasals are tapered, extend-
ing beyond the premaxillae and are
shorter than in B. granti or B. salomonseni
(shortest in B. russatus). The braincase is
the broadest among the four species,
nearly rounded and dorsolaterally inflat-
ed, and more than two-thirds as high as
wide. Batomys hamiguitan has absolutely
shorter frontals than B. salomonseni or B.
granti (shortest in B. russatus). Relative to
both skull length and length of rostrum,
however, B. hamiguitan has the shortest
frontals (less than a third of GLS and less
than four-fifths of LR) whereas B.
russatus has the longest (more than a
third of GLS and longer than LR).
The zygomatic breadth of B. hamigui-
tan is a little more than half of the GLS
(Table 3), and differs little from that of
B. granti or B. salomonseni in absolute
breadth (narrowest in B. russatus; Fig. 6).
The zygomatic plate (Table 2) is only
slightly narrower than in B. granti or B.
salomonseni (narrowest in B. russatus),
but the orientation of the zygomatic arch
relative to the cranium is distinct in B.
hamiguitan. The attachment of the squa-
mosal root is lower relative to the height
of the cranium, and its interior edge forms
a wider and deeper sigmoid notch prior to
attachment to the jugal. The resulting
shape of the zygomatic process is a
pronounced backward-dipping arch that
is lower posteriorly than in congeners.
The incisive foramina of B. hamiguitan
(Fig. 4, Table 2) are most similar in
Fig. 5. Occlusal views of the right upper and
right lower molar rows of Batomys hamiguitan:
FMNH 190164 (left), FMNH 190163 (holotype,
middle and right). The laminar configuration
outlining cusp t9 (labial) on the third upper molar
is distinct in a young adult (left); also evident but
more worn in the holotype (middle). The short and
broadly angled posterior cingulum at the back of
first and second upper molar of a young adult (left)
are distinct. Note the shorter and rounder lingual
cusps of the first and second lower molars of the
holotype (right), as well as its cordate and oblong
porterior cingulum behind first and second molars,
respectively. Scale bar 5 5 mm.
VOLUME 121, NUMBER 4 421
Fig. 6. Dorsal and ventral views of the crania and lateral view of the mandibles of three species of
Batomys: top, B. granti (FMNH 62504); middle, B. salomonseni (FMNH 148171); and bottom, B. russatus
(FMNH 189788).
422 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
length to B. granti, and in both species are
absolutely longer than in B. salomonseni
or B. russatus, but only slightly narrower
than in B. granti or B. salomonseni
(narrowest in B. russatus; Fig. 6). Also,
the incisive foramina of B. hamiguitan
extend posteriad beyond the anterior
margins of the alveoli of M
1
(Fig. 4). In
adult specimens of the other species, there
is a distinct gap of ca. 1 mm or more
between the posterior margins of the
foramina and M
1
(Table 2; also see Figs.
8, 24, 25 in Musser et al. 1998). Although
this condition appears consistent among
adults, three of the four sub-adults of B.
salomonseni that we examined (FMNH
74853, 92829, 175563) showed similar
placement of the incisive foramina rela-
tive to the anterior margins of the M
1
as
seen in adult B. hamiguitan.
The palate and palatal bridge of B.
hamiguitan (Table 2) are shorter than in
either B. granti or B. salomonseni (shortest
in B. russatus), but palatal breadth at
both M
1
and M
3
(Table 2) varies little
among them, being only slightly narrower
in B. hamiguitan than in B. granti or B.
salomonseni (narrowest in B. russatus;
Fig. 6). The bullar dimensions of B.
hamiguitan are similar to those of conge-
ners (Table 2, Fig. 4). The bullae are
slightly smaller and positioned lower than
in B. granti or B. salomonseni (smallest in
B. russatus ). The bulla is more similar to
B. granti and B. russatus in the possession
of a bony eustachian tube that is wider
than that seen in B. salomonseni.
The basicranial region of B. hamiguitan
is similar to that of B. salomonseni.
Specifically, the carotid circulatory pat-
tern is the derived condition that is also
characteristic of B. dentatus, B. granti,
and B. salomonseni, rather than the basal
murid pattern seen in B. russatus (see Fig.
28 in Musser et al. 1998). The alisphenoid
strut is absent in B. hamiguitan,asitisin
B. granti, B. russatus,andB. salomonseni;
a strut is present in B. dentatus (see Fig.
26 in Musser et al. 1998).
Basic dental features are similar among
all species of Batomys, differing mainly in
relative dimensions (Table 2, Figs. 4, 6;
also see Figs. 12–15, 21 in Musser et al.
1998). The upper incisors of B. hamigui-
tan emerge at right angles to the rostrum,
have smoothly rounded tips (tapered
inward to straight in younger specimens),
and a slightly convex and smooth anterior
surface of yellowish-orange enamel. The
breadth across the incisor tips is most
similar to B. granti and is slightly
narrower than in B. salomonseni (narrow-
est in B. russatus). The diastema is
absolutely shorter than in either B. granti
or B. salomonseni but longer than B.
russatus (Table 2).
The molar tooth row of B. hamiguitan
is most similar to B. salomonseni (Table 2,
Fig. 5), with both being absolutely short-
er than in B. granti and longer than in B.
russatus. The molars of B. hamiguitan
have the same high crown and broad
cuspidate rows seen in other Batomys but
are closer to B. granti and B. salomonseni
in relative size than to the smaller B.
russatus. Compared with either B. granti
or B. salomonseni, however, the maxillary
molars of B. hamiguitan have smaller
lingual cusps t1, t4 and t7, as well as
smaller cusps t8 on M
1
and M
2
(normally
fused with the posterior cingulum in older
specimens). Similarly, the mandibular
molars of B. hamiguitan have shorter
and rounder metaconids and entoconids,
as well as smaller posterior cingula than
in B. granti or B. salomonseni.
In B. hamiguitan, lingual cusps t1, t4,
and t7 are distinct, whereas the remaining
cusps in each row are fused and marked
only by broad laminar outlines (Fig. 5).
As with congeners, medial cusps t2, t5,
and t8 on M
1
are broadly domed anteri-
orly and each constitutes about 75% of
the occlusal surface of its respective
cuspidate row. On the second row, cusp
t5 is merged with the labial t6, but in
younger individuals of B. hamiguitan,t6
can be easily observed (FMNH 186819,
VOLUME 121, NUMBER 4 423
190161). On the third row, t8 is fused with
the posterior cingulum to form an even
broader occlusal surface than in the upper
two rows, the latter forming an arcuate
extension of the posterior laminar outline.
Among the six specimens of B. hamigui-
tan that we examined, however, only the
holotype (FMNH 190163) has no evident
trace of a posterior cingulum.
On both M
2
and M
3
of B. hamiguitan,
the first row of cusps lacks t2 but retains a
prominent, circular to ovate, lingual cusp
t1. The labial cusp t3 is usually vestigial,
manifested only by a narrow cingular
shelf on the lower anterolabial edge of
each molar, although in the holotype
(FMNH 190163) a small but distinct t3
is evident on M
2
(Fig. 5). In contrast, t3
of the same molar on B. salomonseni is
persistent and distinct on at least 75% of
the 21 specimens we examined. As on the
first molar, the remaining cusps in the
second and third rows of M
2
and M
3
of
the new species are fused into broad
basins with laminar outlines. Batomys
hamiguitan is notable in retaining a
distinct trace of t9 in the lingual laminar
outline of M
3
. This persistence of t9
on M
3
is evident in all the specimens
that we examined (Fig. 5) but is most
evident among young adults (e.g., FMNH
190161, 190164). This condition may
depend on the age of the individual, and
the evidence of t9 is less likely to be
retained as the molars become worn. For
instance, among specimens of the other
species that we examined, only the two
subadults (FMNH 74853, 92829) of B.
salomonseni exhibited this characteristic
(see also Fig. 12 in Musser et al. 1998),
whereas all adults, except for oldest, retain
an undifferentiated laminar outline fram-
ing the basin of the fused cusps t8 and t9.
The mandible of B. hamiguitan (Ta-
ble 2, Fig. 4) is similar in most respects to
that of its congeners, differing only in
relative size and condition of a few
features. Batomys russatus has the short-
est and smallest mandible among conge-
ners (Fig. 6, Table 2). Batomys hamigui-
tan is closest to B. granti and B.
salomonseni in length of the dentary but
differs from them in its smaller and
narrower angular process, shorter and
narrower condyloid process, and a short-
er coronoid that is broadly angled from
the condyloid process. The mandibular
molar toothrow and lower incisors of B.
hamiguitan are shorter than in B. granti or
B. salomonseni (Table 2, Fig. 5). On both
M
1
and M
2
of the holotype, the posterior
cingulum is cordate and small relative to
the breadth of the occlusal surface of the
second and third cuspidate rows, and
barely a third of the width of the third
row. In contrast, the posterior cingulum
of M
1
and M
2
in B. salomonseni is
absolutely and relatively wider, account-
ing for as much as half of the width of the
occlusal surface of the third cuspidate
rows (see for instance Fig. 14 in Musser et
al. 1998) and is wider still in B. granti,
accounting for as much as two-thirds of
the width of the occlusal surface of the
third row (FMNH 188321). The shape of
the posterior cingulum, however, appears
to vary with age of the individuals. In the
younger specimens of B. hamiguitan, the
shape varies from almost round to
oblong. On the other hand, the cordate
posterior cingulum in B. salomonseni (see
Fig. 14 in Musser et al. 1998) appears to
be more common among young individ-
uals than among adults we examined,
which have a more round to oblong-
shaped posterior cingulum especially on
M
2
.
Ecology and conservation.—In a recent
survey of the mammals of Mt. Hamigui-
tan (Balete et al. 2008b), Batomys hami-
guitan was recorded in transitional low-
land/montane forest at 950 m and in
primary montane forest at 1128 m. At
ca. 545 m elevation, extensive trapping
effort (924 trap-nights) failed to record B.
hamiguitan. Its occurrence in upper mon-
tane and mossy forest at higher elevations
could not be ascertained because no
424 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
trapping was conducted above the type
locality. Batomys hamiguitan appears to
be relatively more abundant in primary
montane forest at the type locality
(1128 m) than in transitional lowland/
montane forest at 950 m (0.91% and
0.12% trap success, respectively, using
the same bait). Elevational distribution
and habitat associations of B. hamiguitan
are similar to those of B. granti and B.
salomonseni. On Mt. Kitanglad, B. salo-
monseni was documented from residual
montane forest at 1450 m up to old-
growth mossy forest at 2375 m, and in the
Central Cordillera of Luzon, B. granti
was recorded in montane and mossy
forest between 1600 m and 2480 m (Hea-
ney et al. 2006, Musser et al. 1998). In
contrast, B. russatus appears to be limited
to the lowlands on Dinagat Island (Mus-
ser et al. 1998).
Vegetation at the type locality and the
adjacent site on Mt. Hamiguitan where
specimens were recorded was dominated
by Podocarpaceae, including Podocarpus,
Dacrycarpus and Dacrydium spp., as well
as Araucareaceae (Agathis) and Myrta-
ceae (Syzygium spp.). Mountain agoho
(Gymnostoma sp.) was present but un-
common above 1000 m. Understory and
forest floor vegetation included erect
pandans (Pandanus spp.), tree ferns (Cy-
athea spp.) and lianas, rattans (Calamus
spp.), and climbing pandans (Freycinetia
spp.). Ferns, pitcher plants (Nepenthes
spp.) and orchids were common epi-
phytes. Mosses, lichens, and liverworts
covered trunks and branches of trees and
understory vegetation. Canopy height
was typically 5–7 m, with sections along
ridges that were reduced to barely 0.5 m
high (locally referred to as ‘‘bonsai
forest’’). Thin to moderate layers of leaf
litter and humus covered the forest floor
(Balete et al. 2008b).
All eight individuals of B. hamiguitan
were captured in traps baited with roasted
coconut coated with peanut butter; none
were captured in traps baited with live
earthworms. This is a strong indication of
its herbivorous habits, similar to those of
B. salomonseni on Mt. Kitanglad (Heaney
et al. 2006). Stomach contents of six
individuals contained almost exclusively
finely chewed white to dark brown
vegetable matter, as well several pieces
of roughly chewed cotyledons. No evi-
dence of earthworms or arthropods was
found in their stomachs. As with B.
salomonseni on Mt. Kitanglad (Heaney
et al. 2006) and B. granti on Mt. Isarog
(Rickart et al. 1991, Heaney et al. 1999),
the diel activity pattern of B. hamiguitan
appears to be exclusively nocturnal (there
were no daytime captures).
Two primiparous females captured in
May (FMNH 190165, 190166) were
pregnant, each with a single embryo
(CRL: 4 mm and 13 mm, respectively).
Three other young adult females captured
during the same period were nulliparous
(FMNH 190161, 190162, 190164). A
young adult (FMNH 186819) captured
in July had a swollen left horn of the
uterus that was highly vascularized, indi-
cating reproductive activity. In B. salo-
monseni on Mt. Kitanglad, pregnancies
were observed in March and several
juveniles were captured during the same
period. Litter size based on the number of
embryos was 1 or 2 (Heaney et al. 2006).
Four additional species of native, non-
volant small mammals occurred at the
sites where the new species was recorded
(Balete et al. 2008b), including two
insectivores (Crocidura beatus and an
undescribed species of Podogymnura)
and two murid rodents (Bullimus bagobus
and Rattus everetti). Both C. beatus and
B. bagobus are endemic to the Mindanao
Faunal Region, and R. everetti is wide-
spread throughout most of the oceanic
islands of the Philippines; the undescribed
Podogymnura is potentially restricted to
the Mt. Hamiguitan range (Heaney et al.
1998, 2006; Balete et al. 2008b). Addi-
tionally, Rattus exulans, a non-native
species, was recorded in disturbed areas
VOLUME 121, NUMBER 4 425
adjacent to the type locality. It appeared
to be restricted to narrow patches of
cogon (Imperata cylindrica) in recently
burned areas surrounding the shoreline
and exposed dry lake bed of Tinagong
Dagat, and along the established foot
trail through the montane forest. Rattus
exulans was not recorded in the intact
forest where the native species occurred
(Balete et al. 2008b).
Trapping data from the high elevation
habitats where Batomys hamiguitan oc-
curs (transitional lowland/montane and
primary montane forest) indicate that it is
a moderately common species, compara-
ble in relative abundance to B. salomon-
seni on Mt. Kitanglad (Heaney et al.
2006, Balete et al. 2008b). Balete et al.
(2008b) noted moderate habitat distur-
bance at sites where the new species was
recorded, mainly involving hunting of
large mammals and mountaineering, but
there was no direct exploitation and the
population of B. hamiguitan appeared
stable where it occurred. However, several
potential factors existed that might neg-
atively affect B. hamiguitan, including
mining of adjacent ultramafic outcrops,
unregulated tourism, and hunting of
small mammals for food by local people
(Balete et al. 2008b). We recommend a
direct assessment of the vulnerability of
this species to these activities, as well as
increasing the current area of Mt. Hami-
guitan Wildlife Sanctuary to ensure pro-
tection of representative habitats on Mt.
Hamiguitan.
Biogeography.—Few mountains on
Mindanao have been sampled extensively,
and only Mt. Kitanglad has been sur-
veyed thoroughly (Heaney et al. 2006).
The limited data suggest that the moun-
tains of central Mindanao share a fairly
homogeneous small mammal fauna, per-
haps associated with the rather homoge-
neous geological history of this part of
Mindanao (Musser & Heaney 1992,
Sajona et al. 1997, Heaney et al. 2006).
Because the several mountain masses of
eastern Mindanao are both physically
isolated (Fig. 1) and of different geolog-
ical origin from one another (Sajona et al.
1997), we predicted that they would each
be found to support endemic species of
mammals, as we have seen in parallel
situations on Luzon Island (Rickart et al.
1998, 2005; Balete et al. 2006, 2007,
2008a). The discovery of Batomys hami-
guitan is consistent with this prediction
and also strengthens the perception of a
general pattern of endemism in highland
areas across the entire Philippines (Hea-
ney & Rickart 1990, Steppan et al. 2003,
Heaney 2004, Jansa et al. 2006, Balete et
al. 2007, 2008a).
Acknowledgments
We are grateful for the help many
people and institutions extended to us
while doing fieldwork on Mt. Hamigui-
tan, and in particular, we thank the
following: P. Balicao, R. Bravo, F.
Bernales, E. Delima, J. Donato, R.
Fernandez, R. Gomez, J. Jimenez, V.
Jimenez, G. Opiso, J. Sarmiento, M.
Silvosa and D. Tablado. Permission to
conduct fieldwork was granted by the
Department of Environment and Natural
Resources (DENR)–Region XI, with the
cooperation of the local government units
(LGU) of San Isidro and Mati Munici-
palities, Community Environment and
Natural Resources Office (CENRO)–Lu-
pon, the Protected Area Management
Board (PAMB) of Mt. Hamiguitan, and
Protected Area Superintendent (PASU)
N. Pilotos. Funding for field work was
provided by the Critical Ecosystem Part-
nership Fund, through the Eastern Min-
danao Corridor project of the Philippine
Eagle Foundation Inc. and Conservation
International (CI). We thank M. Carle-
ton, K. Helgen, and S. Olson for con-
structive comments on an earlier draft of
this paper. Funding for museum studies
was provided by the Barbara Brown
Fund for Mammal Research of the Field
426 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
Museum and a grant from the Grainger
Foundation. Assistance with museum
studies was provided by J. Phelps, M.
Schulenberg, W. Stanley, and B. Strack.
Skull photographs were taken by J.
Weinstein, and the figures were prepared
by L. Kanellos.
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Appendix 1
Specimens Examined
We examined all of the available specimens of
Batomys housed at the Field Museum, Chicago
(FMNH; n 5 46). Specimens were prepared as study
skins with cleaned skulls, complete skeletons, or
fixed in formalin and stored in 70% ethyl alcohol
(some with skulls subsequently removed and
cleaned).
Batomys granti (n 5 7).—Luzon Island, Kalinga
Province, Balbalan Municipality, Barangay Balba-
lasang, Amlicao, 1800 m, 17u269300N, 121u049150E
(FMNH 169126); Mountain Province, Mt. Data
(FMNH 62503, 62504); Bauko Municipality, 0.1 km
E south peak Mt. Data, 2290 m, 16.85888uN,
120.86078uE (FMNH 188323), 0.75 km N, 0.6 km
E south peak, 2241 m, 16.86287uN, 120.86108uE
(FMNH 188321); Barlig Municipality, 0.4 km N,
0.4 km W Mt. Amuyao peak, 2480 m, 17.01727uN,
121.12393uE (FMNH 193689); 1.75 km N, 0.4 km
W Mt. Amuyao peak, 1885 m, 17.02929uN,
121.12466uE (FMNH 193691).
Batomys salomonseni (n 5 30).—Mindanao Is-
land, Bukidnon Province, Kitanglad Range, Mt.
Kitanglad, 10.6 km S, 2.8 km W Sumilao Pobla-
cion, 1450 m, 8u119200N, 124u559200E (FMNH
167385); 10.7 km S, 2.9 km W Sumilao Poblacion,
1450 m, 8u119100N, 124u559100E (FMNH 167386);
11.5 km S, 2.2 km W Sumilao Poblacion, 1500 m
(FMNH 167384); Mt. Imbayao, 15 km S, 7 km E
Baungon, San Vicente Municipality, 1800 m, 8u99N,
124u459E (FMNH 146719, 146720, 147103, 147104);
Mt. Nangkabulos, 16.5 km S, 4 km E Camp
Phillips, 1900 m, 8u10.59N, 124u519E (FMNH
147927, 147929, 147933, 147934, 147944, 148163–
148165); Mt. Nangkabulos, 15.5 km S, 4 km E
Camp Phillips, 2250 m, 8u9.59N, 124u519E (FMNH
147931, 147940, 147941, 148170–148173); Mt. Du-
lang-dulang, 15 km S, 11 km W Dalwangan,
Malaybalay City, 2375 m, 8u7.59N, 124u569E
(FMNH 148033, 148034); Mt. Kitanglad, 5000 ft
(1524 m), (FMNH 92823, 92826–92829); Mt. Ki-
tanglad, 1600 m (FMNH 74843).
Batomys russatus (n 5 1).—Dinagat Island,
Surigao del Norte Province, Loreto Municipality,
Bgy Cambinlio, Balitbiton, 350 m, 17u27.59N,
122u04.19E (FMNH 189788).
Batomys hamiguitan (n 5 8).—See ‘‘Taxonomic
description’’ above.
428 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
