Journal of Threatened Taxa |
www.threatenedtaxa.org | 26 June 2020 | 12(9): 15975–15984
ISSN 0974-7907 (Online) | ISSN 0974-7893
(Print)
doi: https://doi.org/10.11609/jott.5615.12.9.15975-15984
#5615 | Received 13 December 2019 | Final
received 12 May 2020 | Finally accepted 29 May 2020
A new report on mixed species
association between Nilgiri Langurs Semnopithecus johnii
and Tufted Grey Langurs S. priam
(Primates: Cercopithecidae) in the Nilgiri Biosphere Reserve, Western Ghats, India
K.S. Chetan Nag
JAIN (Deemed-to-be University),
#319, 25th Main Road, 17th Cross, J P Nagar 6th
Phase, Bengaluru, Karnataka 560078, India.
ks.chetan@jainuniversity.ac.in
Editor: Mewa Singh, University of
Mysore, Mysuru, India. Date of publication:
26 June 2020 (online & print)
Citation: Nag, K.S.C. (2020). A new report on mixed species association
between Nilgiri Langurs Semnopithecus
johnii and Tufted Grey Langurs S. priam (Primates: Cercopithecidae)
in the Nilgiri Biosphere Reserve, Western Ghats,
India. Journal of Threatened Taxa 12(9): 15975-15984. https://doi.org/10.11609/jott.5615.12.9.15975–15984
Copyright: © Nag 2020. Creative
Commons Attribution 4.0 International License.
JoTT allows unrestricted use, reproduction,
and distribution of this article in any medium by providing adequate credit to
the author(s) and the source of publication.
Funding: The present study was supported by a grant from Department of Biotechnology, Government of India (Grant No. BT/PR-7127/BCE/08/445/2006) to Dr.
K. Praveen Karanth.
Competing interests: The author declares no competing interests.
Author
details: Chetan Nag K S, is
a Research Assistant Professor at JAIN (Deemed-to-be-University), Bengaluru
broadly interested in terrestrial ecology with emphasis on urban ecology. His
overarching research goal is to understand processes that drive biological
diversification due to human influence (rapid evolution). He is interested in
animal species adaptations to challenging situations in non
urban, urban and suburban environments and he plans to achieve this
through field and lab experiments within a fundamental
(evolutionary/ecological) and applied (conservation-oriented) framework.
Acknowledgements: The present
study was partially supported by a grant from Department of Biotechnology,
Government of India (Grant No. BT/PR-7127/BCE/08/445/2006) to Dr. K. Praveen Karanth,
Professor, CES, IISc, Bengaluru). I am thankful to Peter Kappeler
and German Primate Centre for providing travel grant to attend the 8th Göttinger Freilandtage bi-annual
international conference, Germany. I am indebted for the comments of Chaitra,
M.S., Carola Borries and Hari Sridhar which greatly improved the manuscript’s
readability. I greatly benefitted from the comments of E. Heymann,
Tim Clutton Brock, Carel
van Schaik, Bernard Thierry, Mewa Singh, and Werner Kaumanns at the 8th Göttinger Freilandtage bi-annual international conference, Germany
meeting. I would like to thank the Chief Wildlife Warden, Kerala Forest
Department of permission to conduct the study; Rajan
(field guide) and the park manager of Silent Valley National Park, Kerala,
India. I also thank the officials of the Tamil Nadu Forest Department and their
staff for help in the field. I am indebted to Aarohi
Research Foundation and Center for Ecological
Sciences, Bangalore for all the assistance.
I am thankful to individuals like R. Sukumar, Suresh, H., P. Seshagiri, Tarsh Thaekkara, Shravan, Ajith Kumar, Praveen Karanth for comments; Santhosh, M.S., Ravi Chellam, Pramod Padmanabhan, Nameer,
Pradeep Pai, Padmawathe,
Late B. Shailesh Kamath, Vijay Kumar Krishnamurthy, Vishnu Dhople,
Kumar (Masinagudi), Dinesh K.P., and P. Anjana
Shenoy for all their help in various capacities during the course of this
study.
Abstract: Phylogenetic conservatism or
rapid anthropogenic habitat modifications could increase the incidences of
interspecific associations of Hanuman and Nilgiri
langurs (Family: Cercopithecidae, subfamily: Colobinae) in the southern Western Ghats. Opportunistic surveys were conducted at the
Silent Valley National Park, Kerala and around Devimalai
Ghats, Tamil Nadu for Tufted Grey-Nilgiri
Langur association. Based on the observations from Researchers, field
assistants, forest staff, and local people, the data in terms of the time of
the sighting, number of individuals, phenotypes of individuals, and the time
the interaction lasted, were recorded.
The study reports data on a troop of Nilgiri
Langurs (N=13) around O Valley tea estate at Devimalai
Ghat, Gudalur, Tamil Nadu
with some hybrid looking individuals and a Tufted female Grey Langur amongst
them. A total of six and two uni-male troops of
Nilgiri Langurs and grey langurs respectively
with Tufted female Grey Langurs, and aberrant coat colored
infants observed at the Neelikkal section of Silent
Valley National Park are also reported. The study reasonably speculates that
there could be more such locations in the southern western ghats and emphasizes the need for more systematic surveys
to understand and explore the ecology, behavior,
molecular, and other likely factors contributing to the conservation of
vulnerable Nilgiri langur (Semnopithecus
johnii) populations.
Keywords: Colobines, Coromandel Sacred Langur,
mixed-species association, southwestern India.
Introduction
Interspecific
short-term associations among animal groups are known to naturally occur in the
context of competition for food (Dickman 1992), mutual benefit (Oates & Whitesides 1990), and hybridization (Anderson 1948; Arnold
1997; Alberts & Altmann 2001; Arnold & Meyer 2006). Such associations have generated varied
interests among ecologists, behavioral biologists,
and geneticists (Evans et al. 2001; Hewitt 2001; Keller et al. 2010; Cortes et
al. 2019); however, when two different species live together as a single
cohesive unit, interspecific associations are difficult to explain. These associations are difficult to
understand when they are seen amongst the species which have well defined
social organizations like primates. In
other words, biologists are aware of the purpose of the casual encounters of
two different species, however, there seems to be a dearth of information in
biological literature in the case of two species that exist as a single group
going beyond the casual encounters.
Mixed species associations
(hereafter referred to as MSAs or interspecific associations) have been usually
observed in animals that live in social groups such as birds, ungulates,
primates, and cetaceans (Terborgh 1990; Grubb 1999;
Krause & Ruxton 2002; Stensland et al.
2003). There have also been a few
interesting studies of associations between species from different taxonomic
orders (Rodman 1973; Hayashi, 1975; MacKinnon & MacKinnon 1978; Waterman
& Roth 2007; Haugaasen & Peres 2008; Grueter et al. 2010).
There is a debate that is available on the formation of mixed troops in
primates in general and colobines in particular (Phillips-Conroy & Jolly
1986; Gautier 1988; Yeager & Kirkpatrick 1998; Cords 1990; Burton &
Chan 1996; Heymann & Buchanann-Smith
2000; Mitani et al. 2000; Stensland
et al. 2003; Rehg 2006; Reyer
2008; Werner et al. 2008). Terms like polyspecific associations and mixed-species associations
have been applied synonymously to similar phenomena. While some studies have defined polyspecific associations in the context where two or more
different species intermix without any physical interactions per se, others
define MSAs as species interspersed literally (though for a little time)
behaving like members of a single group foraging, grooming with occasional
mating as well (Burton & Chan 1996).
Such associations are known to vary in duration, frequency, range, and
ecological and behavioral relations largely depending
on the type of groups/species interacting (Cords 1990; Burton & Chan 1996;
Porter 2001; Rehg 2006).
The majority of
the available literature related to mixed associations in primates are derived
from African primates (Klein & Klein 1973; Struhsaker
1981; Gautier-Hion et al. 1983; Waser
1984; Cords 1990; Oates & Whitesides 1990;
Chapman & Chapman 2000; Stensland et al. 2003; Eckardt & Zuberbühler 2004). The reasons for such associations in African
primates have been explained and well documented (Schaik & Hörstermann 1994; Freeland 1977; Stensland
et al. 2003; Fam & Nijman 2011; Cortes et al. 2019), however, not much
literature is available on mixed associations among Asian primates with respect
to behavioral, ecological, and evolutionary topics
illustrating the range of factors, processes, and mechanisms that affect
associations and make similar inferences apart from a few studies (Tables 1,
2).
Taken together,
these reviews suggest that MSAs amongst Asian primates seem to be fewer in
comparison to African primates.
Available data do not indicate whether fewer observations of such MSAs
are due to sampling bias or due to lesser proportional existence in Asian
colobines. The data available on a few
instances of the MSA amongst Asian colobines are predominantly from southern
Asia (Table 1). The associations in case
of Tufted Grey Langurs and Nilgiri Langurs, colobines
of southern India have only been documented in the past by a few studies around
the Palghat gap (Chellam 1985; Hohmann 1988, 1991;
Ramachandran & Joseph 2001) in the Western Ghats. Until now, associations between these
colobines of southern India have only been recorded in Silent Valley, Top Slip,
and Kalakkad-Mundanthurai areas in the Western
Ghats. Despite these pieces of evidence,
the available literature does not show any systematic analysis of MSAs among
the colobines of the entire southern Asian region.
Tufted Grey
Langurs and Nilgiri Langurs of southern India are
well known distinct species, easily distinguishable by pelage color and vocalizations (Brandon-Jones 2004; Hohmann 1988,
1991). The Hanuman Langur also called
Grey or Common Langur species are dispersed throughout most of India and Sri
Lanka (Ellerman & Morrison-Scott 1966; Oates et al. 1994), and are also
found in parts of Pakistan, Nepal (Roonwal 1984;
Oates et al. 1994), Bhutan, and Bangladesh (Choudhury 2007). They are known to occur in a wide range of
habitats from arid regions on the edge of the desert in Rajasthan to the
rainforests of the Western Ghats and at altitudes from sea level (Nag et al.
2011) to 4,270m above mean sea level in the Himalaya (Hrdy
1977; Bishop 1978). The Tufted Grey
Langur or Coromandel Sacred Langur or Madras Grey Langur Semnopithecus
priam groups are organized into uni-male (only one adult male with more of other age and
sex classes), multi-male, and all-male groups.
On the other hand,
Nilgiri Langur or the Black Leaf Monkey Semnopithecus johnii
is endemic to the rainforests of the Western Ghats of Tamil Nadu, Kerala, and
to the hills of Coorg in Karnataka (Ryley & Shortridge 1913; Tanaka 1965; Sunderraj 2001; Kumara &
Singh 2004). The Nilgiri
Langurs are usually found in tropical evergreen forests at elevations over 500m, however, in the habitats of the Kalakad-Mundanthurai Tiger Reserve (KMTR) in the
Tirunelveli Hills of Tamil Nadu, they are found even at an elevation of 180–200
m (Hohmann 1989; Sunderraj 2001). Nilgiri Langur
groups are organized into one or uni-male,
multi-male, all-male, and all-female groups, however, multi-male and all-female
groups are rare in Nilgiri Langurs (Tanaka 1965;
Poirier 1968a; Sunderraj 2001).
In this paper, I
briefly describe an opportunistic observation on Nilgiri-Grey
Tufted langur associations in the Nilgiri Biosphere
Reserve of southwestern India and add some relevant questions to the ongoing
debate on interspecific interactions.
Study area
The study was
opportunistically conducted at Nilgiri Biosphere
Reserve in the southern Western Ghats of southern India. The first locality was at Neelikkal
range, Silent Valley National Park, Kerala and the second locality was around O
Valley tea estate, Devimalai Ghats (11.482N &
76.512E), a hilly terrain between Gudalur-Naduvattam-Ooty
road interspersed with other tea estates at an elevation of 1,365m with an
average rainfall of 3,000mm per annum.
Survey
Opportunistic
surveys were conducted at the Silent Valley National Park, Kerala (December
2010), and around Devimalai Ghats (December 2019) for
Hanuman Langur and Nilgiri Langur association. The attempts were primarily focused to
identify MSAs or hybrid members (only on morphotypic
features) in the troops. The survey was
primarily conducted in the southwestern part of the park, particularly in the Neelikkal area for a week based on earlier reports
(Ramachandran & Joseph 2001) at Silent Valley, and twice around O Valley Devimalai Ghat road based on
anecdotal reports and observations.
During each visit, an attempt was made to maintain the slow pace in
walking (approximately 1km/h) with frequent pauses to look and listen for
langurs. Upon encountering monkeys, the
data was recorded in terms of the time of the sighting, number of individuals,
phenotypes of individuals, and the time the interaction lasted. Generally, the time of sampling was at
06.00–12.00 h and 15.00–18.00 h. Upon
detecting troops, they were actively followed, maintaining contact as long as
possible. For each of the encounters,
the date and time of group detection was recorded along with the total time
taken for observation period, number of individuals, phenotypes of individuals,
and age-sex class of individuals whenever possible. If the interactions had more than two or more
monkeys of two species engaging in affiliation such as foraging or, traveling
along the same route of progression, or within 50–100 m of one another, the
study scored them as a group (Glenn 1997).
Observations were made using an 8 X 40 Porro
prism binoculars. Researchers, field
assistants, forest staff, and local people were consulted for information on
sightings of MSAs/ hybrids at the sites.
A thorough review of the available literature and the recent reports on
langurs of this area and MSAs was carried out.
Methods described elsewhere (Hrdy 1977) were
followed for defining the age-sex compositions in the Tufted Grey Langur troop.
Results
Silent Valley National Park
In total, six and
two uni-male troops of Nilgiri
Langurs and Tufted Grey Langurs,
respectively were observed in the Neelikkal
section of Silent Valley National Park. Nilgiri Langurs were recorded between 800–1,121 m and
Tufted Grey Langurs at around 913m. A
total of 14km in search of Nilgiri Langurs and Tufted
Grey Langurs was traveled. Nilgiri Langurs and
Hanuman Langurs were observed to co-occur only at the edge of the evergreen
forest habitat. Three Nilgiri Langurs were observed foraging with a Tufted Grey
Langur troop at a distance of about 50–75 m at Neelikkal
for the whole of the study period, however, sexing and photographing these
foraging Nilgiri Langur individuals was not possible
due to limitations of visibility in the canopy.
The nearest troops of Nilgiri Langurs were
located >3km away from this Tufted Grey Langur troop. No aggression by the adults of Tufted Grey
Langur towards Nilgiri Langurs was observed. During the period of observation, Nilgiri Langurs and Tufted Grey Langurs were either seen
moving or feeding together. The same
troop also had an adult Tufted Grey Langur female with aberrant coat color. This female,
which was carrying a suckling infant at the time of observation, had
brownish-black coat color giving an impression of a
possible hybrid individual. In addition,
I sighted a troop of Nilgiri Langurs close to the
Kerala Forest Department camp shed in which an infant with Tufted Grey Langur
coat color carried by a Nilgiri
Langur adult female was observed twice on 16 December 2010 at 07.30h and
16.00h, respectively. Attempts to
photograph them went in vain due to the tree cover and shyness of the Nilgiri Langurs to human proximity. Furthermore, local forest guards and watchers
reported another troop of Nilgiri Langurs in and
around the camp shed area in which three infants/juveniles with Tufted Grey
Langur coat color had been observed which could not
be confirmed during my study period.
O Valley Tea Estate, Gudalur-Naduvattam Road
A troop of 11–13
individuals of Nilgiri Langurs with brownish
individuals was observed near O Valley, Tamil Nadu (11.482N & 76.512E;
1,350m) on 28 December 2019 around 17.00h.
I did not encounter adjacent Nilgiri-Tufted
Grey Langur troops. The study troop at
the time of observation had one adult male, four juveniles, two infants, one sub-adult, four adult females, and one
brownish adult female. An adult brownish
Tufted Grey Langur female (Image 1) was observed at about 5m foraging with Nilgiri Langur troop.
During the period of observation, Nilgiri
Langurs and female brownish Tufted Grey Langur were seen moving and feeding
together. This troop also had two
juveniles with brownish-black coat color (Images 2,
3) giving an impression of a possible hybrid individual. No aggression by the adults of Nilgiri Langur troop towards hybrid looking individual/s
was observed. Tarsh
Thekaekara (a
post-doctoral research associate and tea garden owner where Nilgiri Langurs reside) has personally observed females of
this Nilgiri Langur troop mating with a Tufted Grey
Langur male from a nearby estate named Silver Springs. This male Tufted Grey Langur has never been
observed around this Nilgiri Langur’s troop, however,
Nilgiri Langur females of this troop often have been
observed to initiate the mating with Silver Spring Estate Tufted Grey Langur
male (Tarsh Thekaekara
pers. comm. March 2020).
Discussion
Till date, there
were only three confirmed localities (Silent Valley National Park, Top Slip in
the Anamalais, and Kalakkad-Mundanthurai
Tiger Reserve) in the southern Western Ghats where associations of Nilgiri and Tufted Grey langurs have been reported. This study provides the fourth location of
MSAs in the Nilgiri Hills. Anecdotal observations suggest that the focal
troop is a residential one and thus associations and observations could not
merely be a chance event, however, the association between Nilgiri
and Tufted Grey langurs appears to involve not only hybrids, but langurs who
could be coping in a human-disturbed habitat.
The effects of such associations due to habitat fragmentation could as
well be a possibility to explore and understand these short-term associations
at such localities. The formations of
interspecific associations are a complex phenomenon to explain. A variety of ecological explanations have
been offered. But after a careful
examination of interspecific associations in colobines of southern Asia, the
available data shows that such mixed associations are formed between closely
related species pairs which are recently diverged terminals of a phylogenetic
tree. Given the available evidence of
higher degree phylogenetic conservatism across the primate phylogenies with
respect to the social behavior, it is reasonable to
at least propose an ad hoc hypothesis which warrants rigorous analysis. The hypothesis argues that the MSA in
colobines of southern Asia happens between a pair of recently diverged taxa
that could be due to phylogenetic conservatism (Rendall
& De Fiore 1995; Prinzing et al. 2001) in their
social behavior.
If this hypothesis is true, it
would provide a robust framework to reanalyze the MSA
in colobines.
Recent molecular
phylogenetic analysis of langurs in Asia reveals that Hanuman Langurs are
closely related to Nilgiri Semnopithecus
johnii and Purple-faced langurs S. vetulus (Zhang & Ryder 1998; Karanth
et al. 2008, 2010; Osterholz et al. 2008), which are
distributed in peninsular India and Sri Lanka, respectively. Evidences from molecular data are supported
by both ecological and behavioral data wherein Nilgiri Langurs and Hanuman Langurs are similar with
respect to size of the troop, troop composition and ranging behavior
(Tanaka 1965; Poirier 1968a; Hohmann 1989) and in some behavioral
aspects like infant transfer, role of protection of the infants by males, and
least protective behaviors of mothers (Tanaka 1965;
Poirier 1968b). A review of the
literature on such interactions between other similar sister species of Indian
colobines revealed that there can exist a close interaction amongst these sister
species (Table 1). Both these species
are recently diverged taxa and form a close-knit monophyletic clade in a
phylogenetic tree. Interestingly, a study by Kavana
et al. (2015) while determining the impacts of folivory
on social time between Black-footed Grey Langur Semnopithecus
hypoleucos and Nilgiri
Langur in the Western Ghats concluded that phylogenetic inertia was not a
constraint determining social behaviour of S. hypoleucos
and S. johnii and that physiological
constraint arising from varying degrees of folivory
actually appeared to be the important factor.
Thus, their study inferred that some traits such as degree of folivory and social time are phylogenetically conserved
among Hanuman Langur species and hence, the current study reasonably speculates
that the mixed species interactions and associations between Tufted Grey
Langurs and Nilgiri Langurs of southern Western Ghats
of southern India could be occurring on account of phylogenetic
conservatism.
Conclusions
Taking into
consideration the known distribution of Nilgiri Langurs
and Hanuman Langurs in southern Western Ghats, it is reasonable to speculate
that there could be more such MSAs wherever these two species are
co-distributed in this range and elsewhere in the Western Ghats. In this regard, it is imperative to survey MSAs
in the entire range of the Western Ghats where both Hanuman Langurs and Nilgiri Langurs co-occur possibly yielding more insights on
the biology of these two species groups.
Given the fact
that Gudalur-Naduvettam-Ooty road has high human
influence and disturbances, the study appeals for more rigorous and systematic
surveys on interspecific associations all along the distribution of Nilgiri Langur-Tufted Grey Langur distribution ranges
including the entire Nilgiri District. Future studies should determine the
ecological or habitat constraints facing both (associated) primate groups. These surveys can aid biologists and park
managers to understand the biology of associations and implement appropriate
conservation measures. Insights on such
associations may have implications for conservation especially if induced by
human activities like the introduction of species in areas outside their
natural range, decrease in population densities of closely related species due
to hunting and habitat fragmentation. A
detailed systematic study on ecology, behavior, and
molecular aspects of these associations must be the primary goal for future
studies.
Table 1. Reported interactions of Asian primates from
the literature.
|
Species |
Explanation |
Remarks |
References |
|
Purple faced Langur-Hanuman Langur |
Foraging |
* |
Hladik (1977) |
|
Lion-tailed Macaque-Bonnet Macaque-Hanuman Langurs |
Foraging |
* |
Singh et al. (2010) |
|
Lion-tailed Macaque-Bonnet Macaque-Nilgiri Langurs |
Foraging |
* |
Sushma & Singh (2006) |
|
Lion-tailed Macaque-Hanuman Langurs |
Foraging |
* |
Singh et al. (2010) |
|
Hanuman Langur-Rhesus Macaque |
Antipredatory |
* |
Mathur & Lobo (1989) |
|
Rhesus Macaque-Crab-eating Macaque-Tibetan Macaque |
Foraging |
* |
Burton & Chan (1996) |
|
Rhesus Macaque-Crab-eating Macaque-Japanese Macaque |
Foraging |
* |
Southwick & Southwick (1983) |
|
Tonkean Macaque-Booted Macaque |
Habitat |
* |
Riley et al. (2007) |
|
Kloss’s Gibbon-Mentawai islands Langur |
Foraging |
* |
Tilson & Tenaza (1982) |
|
Kra Macaque-Silvered Leaf Monkey- Javan Grizzled
Langur-Proboscis Monkey |
Foraging |
* |
Kurland (1973) |
|
Rhesus Macaque-Pig-tailed Macaque |
|
Hybrid |
Malaivijitnond et al. (2007) |
|
Crab-eating Macaque-Pig-tailed Macaque |
|
Hybrid |
Bernstein (1967) |
|
Tonkean Macaque-Heck’s Macaque |
|
* |
Watanabe et al.(1991); Bynum (2002) |
|
Moor Macaque-Tonkean
Macaque |
|
Hybrid |
Supriatna et al. (1992); Evans et al. (2001) |
|
Sulawesi Crested Macaque-Heck’s Macaque |
|
* |
Watanabe & Matsumura (1991) |
|
Gorontalo Macaque-Heck’s Macaque |
|
* |
Watanabe & Matsumura (1991) |
|
Rhesus Macaque-Bonnett
Macaque |
|
|
Fooden (2000); Fooden et al.
(1981); Koyama & Shekar (1981); Kumar et al. (2011) |
|
Rhesus Macaque-Crab-eating Macaque |
|
Hybrid |
Stevison & Kohn (2009) |
|
Japanese Macaque-Taiwanese Macaque |
|
Hybrid |
Kawamoto (2005) |
* Lack of empirical evidence to explain the reasons
for association
Table 2.
Documented hybridizations between Asian colobines (wild and captive).
|
Hybridising Taxa |
Location |
Coordinates |
Notes |
References |
|
S. priam X S. johnii |
Indira Gandhi Wildlife Sanctuary, Anamalai, Tamil Nadu, India |
76.846E & 10.469N |
Natural hybrid |
Hohmann (1988, 1991) |
|
S. johnii X S.p. thersites |
Kalakkad-Mundanthurai Tiger Reserve, Tamil
Nadu, India |
77.311E & 8.689N |
Mating photograph |
Chellam (1985) |
|
T. obscurus X S.p. thersites |
Sri Lanka |
NA |
Captive hybrid |
Hill (1939) |
|
S. p. thersites X S.v. nestor |
Sri Lanka |
NA |
Captive hybrid |
Hill (1936) |
|
S. p. thersites X S.v. nestor |
Sri Lanka |
NA |
Captive hybrid |
Hill (1936) |
|
S. priam X S. johnii |
Madura Coats, Ooty, Tamil
Nadu, India |
NA |
Hybrid photograph by Sally Walker |
Brandon-Jones (2004) |
|
Pygathrix nemeaus X T. laotum
hatinhensis |
Vietnam |
NA |
Hybrid captive |
Schempp et al. (2008) |
|
T. pileatus X T. geei |
Bhutan |
90.690E & 27.143N |
Natural hybrid |
Choudhury (2008) |
S—Semnopithecus | T—Trachypithecus |
v—vetulus | p—priam.
For
figure & images - - click here
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