Journal of Threatened Taxa |
www.threatenedtaxa.org | 26 March 2023 | 15(3): 22908–22910
ISSN 0974-7907
(Online) | ISSN 0974-7893 (Print)
https://doi.org/10.11609/jott.7734.15.3.22908-22910
#7734 | Received 01
November 2021 | Final received 24 January 2023 | Finally accepted 22 February
2023
A note on the occurrence of Cremnochonchus conicus
(Blanford, 1870) in Mumbai, India
Naman Kaji
1 & Shubham Yadav 2
1 Department of Zoology, Mithibai College, Vile Parle West, Mumbai, Maharashtra
400056, India.
2 Bombay Natural History Society,
Hornbill House, Shahid Bhagat Singh Rd, Lion Gate,
Fort, Mumbai, Maharashtra 400001, India.
1 namanpxy31@gmail.com (corresponding
author), 2 shubhamy10@gmail.com
Editor: Basudev Tripathy, Zoological Survey of India, Pune, India. Date of publication: 26
March 2023 (online & print)
Citation: Kaji, N. & S. Yadav (2023). A note on the occurrence of Cremnochonchus conicus
(Blanford, 1870) in Mumbai, India. Journal of Threatened Taxa 15(3): 22908–22910. https://doi.org/10.11609/jott.7734.15.3.22908-22910
Copyright: © Kaji & Yadav 2023. 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:
The authors would like to thank Dr. Amrut
Bhosale for his expertise. We would also like to thank and acknowledge Ms. Mrinmayi Dalvi for the lovely illustrations. We also thank
Ms. Sakshi Save for her efforts and valuable inputs.
Members of the genus Cremnoconchus
are known to be restricted to montane streams on the western escarpment of the
Western Ghats, at altitudes between 300 m and 1,400 m (Rao 1989; Reid et al.
2013; Tripathy & Sajan
2020).
Four species
and several varieties were described in the 19th century (Blanford 1869). In 2013, only three described species—C.
syhadrensis, C. conicus,
C. canaliculatus, were considered valid and
recognized from the northern Western Ghats in Maharashtra state, where all can
occasionally be found sympatrically out of the nine
recognized species from the genus Cremnoconchus
(Reid et al. 2013; Tripathy & Sajan
2020).
The gastropod genus Cremnochonchus is endemic to the Western Ghats. The
species being habitat specialist are exclusive to spray zones of waterfalls.
C. carinatus was first recorded by Layard in the
spray zones of waterfalls in Mahabaleshwar and is the only known range for the
species. The species has since been known to be extirpated from that locality (Molur et al. 2011). In 2013, C. carinatus
was no longer considered a valid species and has been clubbed with C. conicus, which were considered sister species (Reid et
al. 2013).
C. conicus has been observed along the
streams and cascades of Conservation Education Centre (CEC), Goregaon in good
populations. Apart from CEC, C. conicus have
been observed in the localities of Mulund, Airoli,
Thane, Maharashtra (19.17630N, 73.01220E), Anushaktinagar, Mumbai, Maharashtra (19.03580N,
72.923330E), Manpada, Thane, Maharashtra
(19.24070N, 72.96390E), and Karnala
Bird Sanctuary, Raigad, Maharashtra (18.88600N, 73.11250E).
The specimens were identified on
the field and by shell specimens using the identification key by Reid et al.
(2013) - turbinate shell shape; one shell rib at the shoulder (2 ribs observed
in a specimen); wide columella; absence of pseudumbilicus;
satin sheen shell surface with microstriae; weakly
calcified operculum with no internal ridge.
The current known habitat
preference of C. conicus is the spray zones of
waterfalls and shallow pools of freshwater (Aravind et al. 2011). Our
observations in CEC add on to this known habitat preference. C. conicus have been observed along the flowing,
freshwater streams of CEC. They are found on the moist rocks present in between
or along the flowing streams. They also lay eggs in clutches of 10–25 on these
boulders. The egg-laying starts in June and lasts up to late July.
Discussion: C. conicus is a habitat specialist gastropod found in the
spray zones of waterfalls of Mahabaleshwar Hills (Molur
et al. 2011). In the light of this new record, C. conicus
not only inhabits the waterfalls but also the freshwater streams originating
from it. It even lays eggs on the rocks present on these streams just above the
flowing water surface. The ecology of eggs needs to be studied further as the
fate of the eggs in this new scenario is unknown. There may be two
possibilities – either the eggs hatch underwater once the stream overflows due
to heavy rains in the month of July or due to change in the habitat conditions,
it has to alter its ecology and spawn in such streams that may overflow and
destroy the eggs.
The current conservation status
of C. conicus is Vulnerable (VU) (Aravind et
al. 2011; Reid et al. 2013), but may require a re-evaluation as this specialist
species, in a rapidly vanishing freshwater habitat, currently faces
anthropogenic pressures (Shubham Yadav, pers. comm. August 2021). C. conicus as well as other snail species are harvested by
the locals for consumption. Apart from that, the freshwater streams are quickly
being polluted due to waste disposal, effluent and organic discharge along and
directly in these streams. The streams in Mahabaleshwar, from where Blanford collected his specimens, have since been polluted
and hence, no species of Cremnocochus were
found during a survey in 2010 (Aravind et al. 2011). Southern Coucal and Starling sp. predation has been observed on C.
conicus. Furthermore, its range considering its
niche can be estimated to be abundant in the pristine streams of northern
Western Ghats. The species needs to be studied further to understand its
ecology and importance as an indicator of freshwater habitat.
For images
- - click here for full PDF
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