phylogenetic relationships and classification of didelphid marsupials ...

134 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 322
associated with collected specimens are less
than 1000 m above sea level (Birney et al.,
1996; Martin, 2003). As noted by Flores et al.
(2007), the distribution of Lestodelphys extends
further south than that of any other
living marsupial.
Marmosops Matschie, 1916
Figures 52, 53
CONTENTS: bishopi Pine, 1981; cracens
Handley and Gordon, 1979; creightoni Voss
et al., 2004; fuscatus Thomas, 1896 (including
carri J.A. Allen and Chapman, 1897; and
perfuscus Thomas, 1924); handleyi Pine, 1981;
impavidus Tschudi, 1845 (including caucae
Thomas, 1900; celicae Anthony, 1922; madescens
Osgood, 1913; oroensis Anthony,
1922; sobrinus Thomas, 1913; and ucayalensis
Tate, 1931); incanus Lund, 1840 (including
bahiensis Tate, 1931; and scapulatus Burmeister,
1856); invictus Goldman, 1912;
juninensis Tate, 1931; neblina Gardner, 1990;
noctivagus Tschudi, 1844 (including albiventris
Tate, 1931; collega Thomas, 1920; dorothea
Thomas, 1911; keaysi J.A. Allen, 1900;
leucastrus Thomas, 1927; lugendus Thomas,
1927; neglectus Osgood, 1915; politus Cabrera,
1913; purui Miller, 1913; stollei Miranda-Ribeiro,
1936; and yungasensis Tate,
1931); ocellatus Tate, 1931; parvidens Tate,
1931; paulensis Tate, 1931; and pinheiroi Pine,
1981 (including woodalli Pine, 1981).
MORPHOLOGICAL DESCRIPTION: Combined
length of adult head and body ca. 90–
195 mm; adult weight ca. 20–140 g. Rhinarium
with two ventrolateral grooves on each
side of median sulcus; dark circumocular
mask present; pale supraocular spot absent;
dark midrostral stripe absent; throat gland
consistently present in adult males of some
species (e.g., M. incanus, M. noctivagus) but
apparently absent in others (e.g., M. impavidus,
M. parvidens). Dorsal pelage unpatterned,
usually some shade of dull grayish
brown, but distinctly reddish or grayish in
some species; dorsal hair bases always dark
gray; dorsal guard hairs short and inconspicuous;
ventral fur self-colored (whitish, buffy,
or brown) or entirely or partially gray based.
Manus mesaxonic (dIII . dIV); manual
claws small, shorter than fleshy apical pads
of digits; dermatoglyph-bearing manual plan-
tar pads present; central palmar epithelium
smooth or sparsely tuberculate; lateral carpal
tubercles externally conspicuous on wrists of
large adult males; medial carpal tubercles
absent in both sexes. Pedal digits unwebbed;
dIV longer than other pedal digits; plantar
surface of heel macroscopically naked (a
microscopic pelage of very short hairs, not
coarse fur, is usually present). Pouch absent;
mammae varying among examined species
from 3–1–3 5 7 to 7–1–7 5 15, anteriormost
pairs ‘‘pectoral’’ when mammae $11; cloaca
present. Tail longer than combined length of
head and body, slender and muscular (not
incrassate), and macroscopically naked
(without a conspicuously furred base); naked
caudal integument uniformly dark (usually
grayish), bicolored (dark above, pale below),
or parti-colored (dark distally, paler distally);
caudal scales in spiral series, each scale with
three bristlelike hairs emerging from caudal
margin; median hair of each caudal-scale
triplet usually much thicker and darker than
lateral hairs; ventral caudal surface modified
for prehension distally (with naked median
groove and apical pad bearing dermatoglyphs).
Premaxillary rostral process long and well
developed in some species (e.g., M. parvidens,
M. pinheiroi) but short in others (e.g., M.
noctivagus) and apparently absent in some
(M. incanus). Nasals long, extending anteriorly
beyond I1 (concealing nasal orifice in
dorsal view), and conspicuously widened
posteriorly near maxillary-frontal suture except
in M. incanus (which has narrow, more
or less parallel-sided nasals). Maxillary turbinals
(viewed through nasal orifice) elaborately
branched. Lacrimal foramina, usually
two on each side, concealed from lateral view
inside orbit (e.g., in M. parvidens) or exposed
on orbital margin (e.g., in M. pinheiroi).
Interorbital region without abrupt constrictions;
supraorbital margins rounded in some
species (e.g., M. parvidens), beaded in others
(e.g., M. noctivagus); postorbital processes
usually absent except in old males of some
species (e.g., M. impavidus 32 ). Left and right
frontals and parietals separated by persistent
median sutures. Parietal and alisphenoid in
32
Postorbital processes in this species are best developed in
AMNH 272760.