Intl. J. of Molecular Zoology, 2011, Vol.1, No.2, 4
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http://ijmz.sophiapublisher.com
5
families:
Tupaiidae
and
Ptilocercidae
;
there are five
genera know as
Anathana
,
Dendrogale
,
Tupaia
,
Urogale
and
ptilocercus
which consist of 20 species (Figure 2).
Genus
Tupaia
having 15 species is the largest genus in
the order. The generic name of
Tupaia
came from Malay
word tupai, which means of squirrel (
Nowak and
Paradiso, 1999)
.
Northern treeshrew (
Tupaiabelangeri
)
and common treeshrew (
Tupaiaglis
)
are two of most
famous species in the
Tupaia
genus.
Figure 2 Species of treeshrews in Order
Scandentia
(
Pettigrew
et al., 1989; Janecka et al., 2007)
Northern Treeshrew (
Tupaiabelangeri
I), also known
as the Burmese tree shrew, can be found in countries
in Southeast Asia. In mainland China, Northern
treeshrew can be found in Guang Xi, Hai Nan, Gui
Zhou, Yun Nan, Si Chuan, Tibet and other regions,
living mainly near tropical and sub-tropical forests,
bushes, and villages. Type locality for this species is
close to Rangoon, Myanmar. There have been 8
Northern treeshrew subspecies named, among which
Tupaiabelangeri
chinensis, also known as the Chinese
treeshrew was named by Anderson in 1879. Chinese
tree shrews are found in Si Chuan (Southwestern
region), Yun Nan and other parts of mainland China.
Type locality for Chinese treeshrew is Bang Xi and
Sang Da Valley of Yun Nan Province. Northern tree
shrew has a body shape similar to squirrels, with body
length of 190 mm to 200 mm, and tail length of
around 160mm. Its tail region is rich in furs, which
disperse toward each side. Adult Northern treeshrews
have body weights ranging from 120 g to 150 g. Front and
hind feet both contain 5 digits with well-developed
and sharp claws. It also has pointy and long mouth
region, and relatively short ears. The eye sockets of its
cranium protrude well toward the back forming boney
eye balls and a relatively large cranial cavity. Fur
colour of type subspecies is reddish brown, with light
grey coloured furs in the region below its jaw and in
the abdominal region.
Tupaiaglis
,
also known as common tree shrew, is a
small mammal in the
Tupaiidae
order. It originates
from Thailand, Malaysia, and Indonesia. Common
tree shrew has one of the largest body sizes among all
tree shrew species. Common tree shrew has an
average body length of 16 cm to 21 cm, and an
average body weight of approximately 190 g. It has
different coloured furs, with reddish brown, grey, or
black colour for back region, and white for abdominal
region. Its long furry tail appears to be greyish brown
colour, and can reach a full body length. The paws are
not covered by furs and are armed with sharp nails. A
region right above its long nose is bare without any fur.
Male and female have similar physiology. According
to data gathered from 21 common tree shrew samples,
the body lengths range from 170 millimeters to 235
millimeters; tail lengths range from 170 millimeters to
242
millimeters, and hind foot lengths range from 45
millimeters to 56 millimeters.
3
Classification Controversy
The
Scandentia
order was once placed in the
Insectivora
and
Primates
order. The members of
Scandentia
have similar habits and appearance to
Insectivora
,
but their skull characteristics are similar
to thosefound in some primitive prosimian, so there
has been a great controversy as to whether treeshrews
should be placed under
Insectivora
or
Primates
.
The
Insectivora
order was later found to be a polyphyletic
group, its members have become independent or been
placed in other orders one after another
(
Bartolomucci
et al., 2002), instead, The
Scandentia
order was
eatablished and was placed under the clade
Euarchonta
the same rank (order) as the primates
according to molecular studies, closely related to
Dermoptera
and
Primates
(
Figure 3).