The species of
Cheirogaleus
Traditionally, only two species of Dwarf
Lemur (genus Cheirogaleus ) have been recognised: C.major (Greater
Dwarf Lemur, of the rainforest of eastern Madagascar) and C.medius
(Fat-tailed Dwarf Lemur, of the dry forest of the west and south of Madagascar).
I examined specimens in the Natural History Museum (London), Muséum National
d'Histoire Naturelle (Paris), Zoologisches Museum (Berlin) and Naturalis (Leiden),
and concluded that C.major actually consists of five different species,
and C.medius of two. The revised classification was published in
International Journal of Primatology , 21 (6): 943-962, December
2000.
As it was illustrated only by a couple of scatterplots, here
I give photographs of key specimens, to point out the key characters that different
the species in each group.
(1) Cheirogaleus medius
group
Skins of the C.medius group in the
NHM (London).
C.medius, Bombetoka (2), C.adipicaudatus , 170km E of
Tuléar (2)
48.162, 48.164; 35.1.8.166, 35.1.8.167
C.medius tends to be lighter in colour, with
brown dorsal stripe; underside broadly creamy or yellow; a partial white collar
round throat; hands and feet white; tail length about equal to head and body.
C.adipicaudatus averages darker, with less well marked
dorsal stripe; underside greyer; white collar shorter, vaguer; only digits are
white; tail much longer than head and body.
Skulls of the C.medius group in
the NHM (London)
C.adipicaudatus, Fort Dauphin; C.medius,
Morondava
91.11.30.5, 72.8.19.9
C.medius has more diastema between anterior and
middle premolars.
C.adipicaudatus,Fort Dauphin; C.medius,
Morondava
91.11.30.5, 72.8.19.9
C.medius has a much longer auditory bulla.
(2) Cheirogaleus major
group
Skins of the C.major group in the
NHM (London)
C.crossleyi, E. Imerima
(l.), Lake Alaotra (rt.); C.major, Antongil Bay; C.ravus, Tamatave
(type) 1939.1289, 48.160; 48.159; 88.2.18.
C.crossleyi : red-brown, grey below (creamy toward
midline); tail equal in length to head and body.
C.major : paler, greyer above, darker and greyer below;
tail much longer than head and body.
C.ravus : dark grey above and below, yellow towards ventral
midline; feet paler to white; tail equal in length to head and body, often white-tipped.
Externally, C.minusculus resembles C.ravus but is much smaller.
Skins of the C.major group in Naturalis
(Leiden)
C.major, Passumbée; C.sibreei,
Passandava
cat.f; cat.a
C.sibreei has more white tipping to fur above; underside
very creamy, this zone extending further up flanks and on outside of thighs.
C.crossleyi , Malewo
KAT.H
Heads and ears of the C.major group
in Naturalis (Leiden)
C.major, Passumbée; C.crossleyi, Malewo
cat.f; KAT.H
In C.major , the ears are naked, their skin not
darkly pigmented; in C.crossleyi they are furry, their skin black.
Skulls of the C.major group in the
NHM (London)
C.major, Maroansetra; C.crossleyi,
Lake Alaotra
35.1.8.169; 48.160
In C.crossleyi the skull is low and flat; the
dentition is smaller, P 2 is low-crowned, and the upper incisors
project forward somewhat. In C.major the skull (both face and braincase)
is deeper; the postcanine teeth are larger, P 2 is higher-crowned,
and the upper incisors are vertical.
C.ravus, Tamatave (type); C.sibreei, Ankeramadinika (type)
88.2.18.3; 97.9.1.160
In C.ravus the skull more is intermediate in
overall shape between C.major and C.crossleyi but more resembles
the latter; the dentition is large, P 2 is high-crowned and the
incisors are vertical, like C.major . C.sibreei resembles
C.crossleyi but has even smaller postcanine dentition.
C.minusculus, Ambositra (type)
11.6.21.1
The skull of C.minusculus is tiny, about equal in size
to the C.medius group; morphologically it tends to resemble C.ravus
.
C.crossleyi, L.Alaotra; C.ravus, Ankaya
48.160; 8.2.6.3.4
C.ravus (and C.minusculus ) have
very reduced M 3 , markedly disturbing the buccal curve of the toothrow;
in C.crossleyi it is unreduced. Other species are intermediate, but
closer to C.crossleyi .