Journal of Threatened Taxa |
www.threatenedtaxa.org | 26 August 2022 | 14(8): 21736–21738
ISSN 0974-7907 (Online) | ISSN 0974-7893
(Print)
https://doi.org/10.11609/jott.7955.14.8.21736-21738
#7955 | Received 06 April 2022 | Final
received 30 June 2022 | Finally accepted 04 August 2022
An unusual morph of
Naja naja (Linnaeus,
1758) (Squamata: Serpentes) from Goa, India
Nitin Sawant 1,
Amrut Singh 2, Shubham Rane 3, Sagar Naik 4 & Mayur Gawas
5
1-5 Department of
Zoology, Goa University, Taleigao Plateau, Taleigao, Goa 403206, India.
1 nitin.sawant@unigoa.ac.in
(corresponding author), 2 amrutsnake@gmail.com, 3 shubhamrane7036@gmail.com, 4 sagarnaik1018@gmail.com,
5 mithilgawas0987@gmail.com
Editor: S.R. Ganesh, Chennai
Snake Park, Chennai, India. Date of
publication: 26 August 2022 (online & print)
Citation: Sawant, N., A. Singh,
S. Rane, S. Naik & M. Gawas
(2022). An unusual morph of Naja
naja (Linnaeus, 1758) (Squamata: Serpentes) from Goa, India. Journal of Threatened
Taxa 14(8): 21736–21738. https://doi.org/10.11609/jott.7955.14.8.21736-21738
Copyright: © Sawant et al. 2022. 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: Ministry of Environment, Forest and Climate Change, Government of India, New Delhi. [Project No.
22018-02/2019-CS (Tax)]
Competing interests: The authors
declare no competing interests.
Acknowledgements: We thank the rescue
team of Animal Rescue Squad (ARS) for giving us the opportunity to examine the
rescued snake. We also thank the Goa Forest Department for successfully
releasing the snake in the wild upon examining. We thank Ms. Seema Vishwakarma
for helping in proofreading and giving her inputs.
Pigmentation serves a
protective role in many animals, including snakes, it functions in camouflage,
warning, mimicry or thermoregulation (Bechtel 1978; Krecsák
2008). Body coloration is a multifunctional trait often characterized by
sophisticated variation (Kemp et al. 2005; Bury et al. 2020).
Therefore, discontinuous phenotypes are generally thought to bear fitness costs
as a result of the primary functions of a given color variation having been
lost (Bury et al. 2020). The maintenance of such phenotypes within populations,
i.e., color polymorphism, thus represents an interesting evolutionary
phenomenon (Forsman 1995; Forsman et al. 2008; Bury et al. 2020).
Melanistic individuals exhibit an increased amount of dark pigmentation, a
possible adaptive hypothesis for melanism in snakes is protection against sun
damage (Lorioux et al. 2008; Jablonski & Kautman 2017).
Melanism is an
example of color polymorphism in which a phenotype is characterized by over
concentration of melanin compared to the typical color (Trullas
et al. 2007; Bury et al. 2020). In small vertebrates, melanistic
individuals are known to bear an elevated risk of predation (Andren & Nilson 1981;
Bury et al. 2020). In the past few years there has been an increase
in the reports of abnormal colorations among Indian serpents, which includes
cases of albinism and leucism (Devkota
et al. 2020; Deshmukh et al. 2020; Mukherjee & Mohan 2021). The spectacled
cobra Naja naja
is a large, venomous snake distributed throughout most of India except the far
north-east, altitudes above 2,000 m, and the Andaman & Nicobar Islands
(Daniel 2002; Das 2002; Whitaker & Captain 2004; Whitaker & Martin
2015).
On 27 May 2021, an
abnormal looking N. naja was rescued at Modelo wado, Assonora
(15.6180N, 73.8970E), Goa at 1005 h. The snake was
initially sighted by an elderly woman who then reported it to other members of
the family, who called the rescuer. The
snake was brownish black in colour on dorsal side and
brownish grey on ventral side (Image 1), eye with visible eye ball (Image 2)
and with a scarcely visible spectacle mark on the hood (Image 3). Ventral
scales were counted as per Dowling (1951). The unsexed individual possessed 187
ventral scales, 25 undivided subcaudal scales and an undivided anal plate.
Dorsal scales at neck: mid-body: tail, were in 24:21:15 rows, respectively.
Nasal scale 1 on each side separated by a pair of pre frontals, 1 frontal, 2
parietals and 2+3 temporal scales on each side, supralabials
7 on right and 8 on left with 3rd & 4th supralabial contacting the eye,
infralabials 8 on right and 9 on left, cuneate scale is present on both the
sides, 1 preocular, 3 postocular and 1 supra ocular
(Image 2). After recording the meristic data, the specimen was handed over to
the Goa Forest Department to be released in a suitable habitat.
The snake was
identified to be Spectacled Cobra Naja naja. The ventral scale count was in the range provided
by Captain & Whitaker (2004) but the observed subcaudal scale count for
complete tail was below the normally recorded range for N. naja. Such black color morph individuals are been
recorded in northwestern region of India where such morphs are said to be
common (Whitaker & Martin 2015; Litschka-Loen et
al. 2019). The snake being rescued from a locality where no major transportation
activity occurs reduces the chances of snake being transported from the region
where they are commonly found. Observed pigmentation is the first reported case
of melanism from this region and appropriate documentation of these types of
individuals will farther our understanding of this phenomenon in N. naja.
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