Journal of Threatened Taxa |
www.threatenedtaxa.org | 26 August 2021 | 13(9): 19373–19375
ISSN 0974-7907 (Online) | ISSN 0974-7893
(Print)
https://doi.org/10.11609/jott.7335.13.9.19373-19375
#7335 | Received 14 April 2021 | Final
received 08 May 2021 | Finally accepted 19 May 2021
Range extension of the Common
Slug Snake Pareas monticola
(Cantor, 1839) (Reptilia: Squamata: Pareidae): a new family record for Nepal
Dipa Rai 1, Manoj Pokharel
2 & Tapil P. Rai 3
1 Department of Environmental
Science, GoldenGate International College, Post Box
4059, Battisputali, Kathmandu, Nepal.
2 Department of Environmental
Science, Tri-Chandra Multiple Campus, Ghantaghar,
Kathmandu, 44600, Nepal.
3 Department of Environmental Science,
Mechi Multiple Campus, Bhadrapur
Municipality-8, 57200, Jhapa, Nepal.
3 Turtle Rescue and Conservation
Centre (TRCC), Arjundhara Municipality-9, 57205, Jhapa, Nepal.
1 raidipa97@gmail.com, 2 manozp12@gmail.com
(corresponding author), 3 tapilprai19@gmail.com
Editor: Raju Vyas, Vadodara, Gujarat,
India. Date of publication: 26 August 2021
(online & print)
Citation: Rai, D., M. Pokharel & T.P.
Rai (2021). Range extension of the Common
Slug Snake Pareas monticola
(Cantor, 1839) (Reptilia: Squamata: Pareidae): a new family record for Nepal. Journal of Threatened Taxa 13(9): 19373–19375. https://doi.org/10.11609/jott.7335.13.9.19373-19375
Copyright: © Rai et al. 2021. 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: None.
Competing interests: The authors
declare no competing interests.
Acknowledgements: We express our sincere gratitude
to Mr. Paul Freed for his help in the identification of the Pareas
monticola.
We are also grateful to the reviewers and editors for their comments
that helped us improve the article.
The family Pareidae Romer, 1956 is composed of a small group of
primarily nocturnal and partly arboreal snakes that have evolved to specialize
in feeding terrestrial snails and slugs (Loredo et
al. 2013; You et al. 2015; Hoso 2017; Uetz et al. 2021). The family is further divided into two
subfamilies (Pareinae and Xylophiinae)
and four genera (Aplopeltura Duméril, 1853; Asthenodipsas
Peters, 1864; Pareas Wagler,
1830; and Xylophis Beddome, 1878) (Deepak et al. 2018; Uetz
et al. 2021). The genus Aplopeltura and
Asthenodipsas are endemic to southeastern Asia (Loredo et al.
2013; Uetz et al. 2021), Xylophis
is endemic to the Western Ghats of peninsular India (Deepak et al. 2018, 2020), whereas Pareas
has a relatively wide distribution in the tropical to subtropical regions
of the Oriental biogeographic realm (Bhosale et al. 2020; Vogel et al. 2020;
Wang et al. 2020).
There are
22 species described within Pareas making it
the largest of all the four genera in the family (Bhosale et al. 2020; Liu
& Rao 2021). The recent surge in the number of studies aiming to resolve
the complex taxonomic and phylogenetic status of Pareas
has led to the addition of several new species (Bhosale et al. 2020; Ding
et al. 2020; Wang et al. 2020; Liu & Rao 2021). Yet, specialized feeding behavior and niche partitioning between the species has
caused increased rate of speciation and sympatric co-occurrence of closely
related Pareas species that appear
morphologically similar (Hoso 2017; Ding et al. 2020;
Vogel et al. 2020). Thus, despite the increasing research, information on the
true diversity, distribution, and natural history of species belonging to this
genus are still far from complete (Bhosale et al. 2020; Vogel et al. 2020).
Pareas monticola (Cantor,
1839) is one of the most widely distributed species of the genus Pareas (Vogel et al. 2020; Uetz et al. 2021).
Occurrence of Pareas monticola sensu stricto has been established from northeastern
India, northern Myanmar, China (Motuo in Tibet and Yunnan
Province), Bhutan, and Bangladesh (Sylhet Division) (Hakim et al. 2020; Vogel
et al. 2020; Koirala et al. 2021). It has not been reported from Nepal, but its
presence in the Darjeeling and Sikkim of India (Uetz
et al. 2021; Vogel et al. 2021) makes it likely for the species to occur in the
adjoining areas of eastern Nepal, which share a similar biotope (Khatiwada et al. 2015). In this paper, we present the first
evidence of occurrence of Pareas monticola sensu stricto from Nepal. Apart from adding a new species of
herpetofauna to the list, this is a new family record for the snakes of
Nepal.
An
individual Pareas monticola
(Image 1a,b) was encountered on 04 August 2020 at 2040 h during a
herpetological survey in Arubote village of Suryodaya Municipality-10 in Ilam
district of eastern Nepal (26.910°N 88.053°E; 1,400m) (Figure 1). The snake was
observed approximately 1 m above the ground moving on a wooden stack along a
trail. The substrate condition was moist due to recent rainfall and there was a
high activity of snails and slugs in the vicinity. The snake had a laterally
compressed slender body with large eyes and vertical pupils. Its body
coloration was brown with the presence of distinct black bars in the
dorsolateral part. A black line extended from eye to the nape and another
similar line from behind the eye to the angle of the mouth (Image 1a,b). We
took several photographs of the snake for identification and expert
consultation. The snake was identified as Pareas
monticola by Mr. Paul Freed based on its
morphological characteristics. The key to the species is loreal and prefrontal
contact with the eye, no preocular, and the presence of enlarged vertebral
scales (Ding et al. 2020).
The present
locality is approximately 25 km (aerial distance) south-west of Darjeeling in
India. The region has a subtropical climate and is characterized by having high
precipitation and humidity, especially during the monsoon (June-–September) (Lillesø et al. 2005). Tea plantation dominates much of the
landscape which is interspersed with human settlements and patches of forest
having Schima wallichi,
Castanopsis indica, and
Alnus nepalensis
as the major tree species (Image 2). Two perennial streams run through the
landscape and join the Jogmai river a few kilometers downstream.
The present
habitat and geographical features are in accordance with other areas where Pareas species are known to occur (Hauser
2017; Ding et al. 2020; Liu & Rao 2021). The nocturnal and partially
arboreal habits of the species have also been supported by our observation.
Snails and slugs mostly prefer moist areas and are highly sensitive to
variation in water availability and temperature (Prior 1985). High rainfall
during monsoon and the presence of perennial water sources should provide
suitable habitat conditions for snails and slugs to thrive in this region,
thereby supporting the occurrence of their predator like Pareas
monticola.
Moreover, due to significant genetic variations among the populations of
Pareas monticola
across their range, it has been identified as a species complex rather than a
single species (Vogel et al. 2021).
Furthermore, our inability to record detailed morphometry and molecular
evidence of the observed specimen hindered us from making confirmation on its
taxonomic status. Hence, we suggest further studies in the tropical to
sub-tropical regions of eastern Nepal to collect meticulous morphological and
molecular data on this species to understand its phylogenetic position.
For
figure & images - - click here
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