Loris tardigradus nycticeboides / Loris
lydekkerianus
nycticeboides
(taxonomic research for the genus not yet finished; possibly a
distinct
species)
Slender loris of the Horton Plains, Ceylon
Mountain slender
loris
Local names: Sri Lanka (for slender lorises in general): Tamil:
thevangu,
theivangu (meaning "the slender-bodied one", a term also used
for emaciated persons), kadu-papa, kada papa (= "baby of the
forest");
Telugu: arawe-papa, devanga-pilli; Sinhalese: unahapuluva (older
authors
record variations such as unahaputuwa, udahapuluwa, hunu
pupuluwa or kalu-unhapuluwa),
kalu-unahapuluva, Nama thevangu or nama-theivangu (because of a
mark on
its forehead resembling the religious symbol namam worn by the
worshippers
of the Hindu god Vishnu)
Review by H. Schulze, A. Nekaris and C. Groves
Reconstruction of the L. t. nycticeboides type,
based on
the skin and description of Osman Hill, 1942 and 1953.
No figures of live animals of this form seem to be available.
Characteristics
A mountain form with shorter limbs than in the other slender loris
forms and an exceptionally long, soft, thick fur (hair length
dorsally
up to 25 mm, ventrally up to 30 mm) which completely covers the
ears and
makes the animal superficially resemble a small slow loris. Ears,
hands
(except distal phalanges) and feet covered with short fur. Pelage
more
similar to tardigradus than to grandis, but not
reddish:
earthy-brown (much lighter than in grandis), no white
frosting.
Limbs paler than back. Ventral colour ochraceous to buff with grey
hair
bases (throat hairs without grey bases). Dark, almost blackish
circumocular
patches, preauricular hair tipped with white. Cutaneous
pigmentation: ear
rims slightly, eyelid margins deeply pigmented; elsewhere pink to
slightly
dusky (Osman Hill 1942, 1953)
Uniqueness L. t. nycticeboides is adapted to a climate with frequent
abrupt
changes of temperature and temperatures sometimes falling to -40C
(see below: habitat). In the lowland forms of Loris which
are adapted
to temperatures above 15 0C, tolerance to cold is
relatively
low, in nordicus, for instance, at 10-120C
environmental
temperature a decrease of rectal temperature of more than 50C
was measured in spite of an increase of basal metabolic rate and
food consumption
(Müller et al., 1985). Even the highland slender loris (grandis)
inhabits areas where temperature probably hardly falls below 100C
(estimated *1) and is clearly less adapted to cold than
nycticeboides,
with shorter hair and sparsely clothed ears.
*1L. t. grandis: temperature values
estimated
for the average altitude of habitat, based on temperature of tardigradus
lowland habitat and an average decrease of temperature of 0.50C
with
every 100 m altitude
Type locality
Horton Plains, Central Province. 1937, estate of Mr.
Tutein-Nolthenius
near the Horton Plains “at a height between 5,000 ft. and 6,000
ft” (Nicholls
1939); holotype in the BMNH labelled: Below Horton Plains, 060
48I N, 800 48I E, 6000 ft., May
1938;
paratype labelled: Horton Plains, 060 48I N,
800
48I E, 7000 ft. (Jenkins 1987). Animals died after
several years
in captivity, labelled years after capture and probably not by the
collector,
data might be inexact.
Distribution area
Endemic to Sri Lankan montane rain and mist forest above 1500 m.
The
size of remaining possible habitat is about 40 000 hectare (400 km2)
in several isolated areas (Werner 1984); nycticeboides has
only
been found in one of these areas, on the Horton Plains.
Abundance
Apparently very rare. Known from only two animals found in 1937 by
Mr. A. C. Tutein-Nolthenius on the Horton Plains, central Ceylon.
“That
the animal is rare in that locality is evidenced by the fact that
Mr. Tutein-Nolthenius
had been on the look out for it for the previous twenty years
without success.
... (Osman Hill, 1942). The animals and two offspring died in
captivity.
Since then, there was only one unconfirmed report of their
occurrence based
on information of rangers (Dmoch, pers. comm.). During a survey in
2001,
rangers and researchers who had worked in the park for years said
they
had never seen or heard any evidence of lorises in the area
(Nekaris, 2001).
Wildlife veterinarian Dr. Vijitha Perera later also did not see any
lorises
there. In 2002, the form was rediscovered during a survey on the
Horton
Plains by Anna Nekaris who managed to see one and an eyeshine
probably
belonging to another one (Nekaris, Jayewardene 2003).
Habitat
Montane evergreen rain and mist forest with Calophyllum
walkeri
WICHT and other typical plant species, annual rainfall 2000 to
5000 mm;
a limited seasonality is observed, without distinct dry period,
but the
ecosystem sometimes suffers from drought (Werner, 1984). Average
temperature:
15.40C, minimum temperature: -40C (Werner
1984; Takahashi
and Arakawa 1981; Eisenberg and Lockhart 1972).
Habitat of L. t. nycticeboides. Left: mist over the
Horton Plains.
Right: pygmy forest. Photos: A. Nekaris
.
Threat and conservation needs
IUCN red data list 2003: EN A1c. During the IPS meeting in August
2002,
nycticeboides
was considered for inclusion on the list of twenty five most
endangered
primates, but finally wasn´t because of insufficient data.
Some facts by A. Nekaris, which should justify listing this form
as
critically endangered in the future:
- extent of occurrence estimated to be less than
100
km2
- the habitat is severely fragmented,
- the existence of the taxa is only reported at a single
location
- the area of occupancy available for the taxa is
continually
declining (IUCN, 2002).
The habitat to which this rare form is endemic needs protection:
according
to Wikramanayake and Gunatilleke (2001), the known high numbers of
endemic
plant and animal species in the Sri Lankan montane rain and mist
forest
are the tip of the iceberg, with increasing numbers of species
discovered
on surveys, and this type of forest can be considered a
super-hotspot within
the endemism hotspot of global importance recognized by Myers et al.
(2000).
The forests are important for the whole island because most of the
large
rivers with water throughout the year have their source here; the
trees
catch humidity from the mist („fog-stripping"), the water is then
retained
as in a sponge and released as clear springs even during drought
periods.
Deforestation leads to drought in the lowland, climatic change and
and
erosion on the mountains (Werner, 1984; Wikramanayake and
Gunatilleke,
2001).
Montane rain and mist forests once probably covered the entire
highland
of Sri Lanka above 1400 - 1600 m. In the past 200 years, however,
most
of these forests have been cleared to establish tea and other
plantations,
pastures or to plant eucalyptus and other alien tree species (Werner
1984;
Wikramanayake and Gunatilleke 2001, quoting Ashton et al. 1997). At
higher
altitudes, on the Horton Plains and elsewhere, the forest have
partly been
replaced by „wet patanas", almost treeless grassland which,
according to
Werner (1984) is the result of habitat destruction, kept open by
frequent
fires, bad soil, overgrazing, dense grass cover and climatic
influences
which prevent young trees outside the protecting forest from
growing. Chambers
(1980) reported severe fires on the patanas caused by visitors,
destroying
shrubs and trees, only Rhododendron arboreum bushes survive.
Patanas: tussock grassland on the Horton Plains replacing the
forest,
thought to be the result of early agriculture. Photo: Colin
Groves.
.
After human impact, secondary forest may persist for a long time;
often
a part of the undergrowth of such secondary forest is dense pygmy
bamboo
which, after flowering and drying, causes danger of fires to which
the
forests are not adapted (Werner, 1984). The remaining patches of
rain and
mist forest are also threatened by illegal logging, collection of
fuelwood
and large scale illicit gemming. Cultivation of cardamom replacing
the
natural undergrowth in some areas prevents regeneration of the
forest (Werner
1984), and the forests especially in the Horton Plains National Park
are
experiencing diebacks; investigations are under way to determine the
causes
(Wikramanayake and Gunatilleke 2001). Highland animal species are
threatened
by habitat fragmentation (Werner, 1984).
The ecoregion has five protected areas that cover less than 500
km2;
none have good protection measures or conservation plans in place
(Wikramanayake
and Gunatilleke 2001).
References:
Chambers, M. R., 1980: Horton Plains - to burn or not to
burn.
Loris - The journal of the Wildlife and Nature Protection Society
of Ceylon
15
(3): 181-183.
Eisenberg, J. F.; Lockhart, M., 1972: An ecological
reconnaissance
of Wilpattu National Park, Ceylon. Smithsonian Contributions to
Zoology
101:
1 - 119. Smithsonian Press, Washington.
Mani, M. S., 1974: Ecology and biogeography in India. Dr.
W.
Junk Publishers, The Hague.
Müller, E. F.; Nieschalk, U.; Meier, B., 1985:
Thermoregulation
in the slender loris (Loris tardigradus). Folia
Primatologica 44:
216-226.
Nekaris, K. A. I., 2001: Final Report: Preliminary Survey
and
Pilot Study of the Slender Loris (Loris tardigradus) in Sri
Lanka.
Sent to several institutions, publication in Primate Conservation:
see
Nekaris, Jayewardene, in press.
Nekaris, K. A. I., 2003: Rediscovery of the Ceylon
Mountain Slender
Loris in the Horton Plains National Park, Sri Lanka. Asian
Primates 8
(3, 4): 1-7.
Nekaris, K. A. I.; Jayewardene, J., in press: Pilot study
and
conservation status of the slender loris (Loris tardigradus
and
Loris
lydekkerianus) in Sri Lanka. Primate Conservation.
Nicholls, L., 1939: Period of gestation of Loris. Nature
(London)
143:
246.
Osman Hill, W. C., 1942: The slender loris of the Horton
Plains,
Ceylon, Loris tardigradus nycticeboides subsp. nov..
Journal of
the Bombay Natural History Society 43: 73-78.
Osman Hill, W. C., 1953: Primates: Comparative anatomy and
taxonomy.
Vol. I, Strepsirhini. Edinburgh University Press, Edinburgh.
Takahashi, K.; Arakawa, H. (eds.), 1981: Climates of
southern
and western Asia. Elsevier, Amsterdam.
Werner, W. L., 1984: Die Höhen- und Nebelwälder auf
der Insel Ceylon (Sri Lanka). [The montane and mist forests of the
island
of Ceylon (Sri Lanka)] Tropische und subtropische Pflanzenwelt 46.
Steiner,
Wiesbaden. (German)
Wikramanayake, E. D.; Gunatilleke, S., 2001: Sri Lanka
montane
rain forests (IM0155). http://www.worldwildlife.org/wildworld/profiles/terrestrial/im/im0155_full.html.
(Series: www.worldwildlife.org,
Wild
World WWW full report. Seen: 24 Sept. 2002.
Originally published in: Wikramanayake, E.; Dinerstein, E.;
Loucks,
C. J. et al., 2001: Terrestrial Ecoregions of the Indo-Pacific: A
Conservation
Assessment. Island Press, Washington, Covelo, CA. Sponsored by
World Wildlife
Fund. ISBN: 1-55963-923-7.
