Freshwater ostracods (Crustacea: Ostracoda) of the
plateaus of the northern Western Ghats, India
Yugandhar Satish Shinde 1, Reginald Victor 2& Kalpana Pai 3
1,3 Department of Zoology, University of Pune, Pune, Maharashtra 411007,
India
1 Department of Zoology, Modern College, Shivajinagar, Pune, Maharashtra411005, India
2 Department of Biology, Sultan Qaboos University, Sultanate of Oman, Muscat, Oman
1 yugandharshinde@gmail.com
(corresponding author), 2 rvictor@squ.edu.om, 3 kalpanapai@unipune.ac.in
doi: http://dx.doi.org/10.11609/JoTT.o3610.5667-70 | ZooBank:urn:lsid:zoobank.org:pub:FA596A02-0519-471B-AF37-090920D475CB
Editor: Okan Külköylüoğlu,Abant Izzet Baysal University, Bolu,
Turkey. Date
of publication: 26 April 2014 (online & print)
Manuscript details: Ms # o3610 | Received 02 May
2013 | Final received 03 April 2014 | Finally accepted 05 April 2014
Citation: Shinde, Y.S., R.
Victor & K. Pai (2014). Freshwater ostracods (Crustacea:Ostracoda) of the plateaus of the northern Western
Ghats, India. Journal of Threatened Taxa 6(4): 5667–5670; http://dx.doi.org/10.11609/JoTT.o3610.5667-70
Copyright: © Shinde et al. 2014. Creative Commons Attribution 4.0 International License. JoTT allows unrestricted use of this article in any medium,
reproduction and distribution by providing adequate credit to the authors and
the source of publication.
Funding: UGC-RFSMS fellowship to YSS and UGC-MRP to KP
Competing Interest: The authors declare no
competing interests.
Acknowledgements: We would like to thank UGC-RFSMS fellowship (to YSS), UGC-CAS
and UGC-MRP (File No. 33-334/2007 (SR)) for providing the funds. We are
grateful to the Head of the Department of Zoology, Pune University and
Principal, Modern College, Pune, for providing the facilities. Avinash Vanjare, Sameer Padhye, Shriraj Jakhalekar, Mihir Kulkarni and Siddharth Kulkarni are acknowledged for their help during the
collections and for providing pictures of the habitats. We would also like to
thank Dr. Neelesh Dahanukarfor giving us the opportunity for collections at Chalkewadisite along with Dr. Sanjay Molur and Ms. Priyanka Iyer. We are also thankful to two anonymous
reviewers for their comments.
For figures, images, tables -- click here
Ostracoda, a class of Crustacea, can be found in
all types of aquatic habitats. They
are also known as “seed-shrimps” because of their tiny seed like appearance
that differentiates them from much larger “clam shrimps”, Conchostracawith concentric rings on valves (Smith 2001).
Temporary
waters are unique habitats in comparison to permanent lotic and lentic habitats
and are characterised by the cyclic process of drying
and filling (Williams 2006). Their
biodiversity is remarkably high consisting of species with adaptations to
withstand draught or frozen periods. Indian temporary freshwater habitats in particular have a high ostracod biodiversity (Deb 1972 & 1983; Victor &
Michael 1975; Battish 1977; 1978 & 1981; Victor
& Fernando 1979; George et al. 1993; Shinde2012).
The
northern Western Ghats consists of flat table-topped hills which are the
result of collective geological events involving basalt flows (Watve 2013). Such flattable tops are popularly called
‘rocky outcrops’. This part of the Western
Ghats has a dry period of about eight months and an approximately four-month
period of monsoon with heavy rains (Dahanukar et al.
2004) during which a large number of temporary water bodies are formed. These habitats host an impressive array
of freshwater micro- and macroinvertebrate fauna
including ostracods.
Studies
on Indian Ostracoda commenced in 1859 and from then
till now 208 species of non-marine Ostracoda, both
extinct and extant have been reported (Battish2000). When compared to states like
Tamil Nadu, Kerala and Punjab, studies on Ostracodain Maharashtra State are very scarce. Before the study by Shinde (2012), the only
investigations on ostracods were those of Deb (1972,
1973). This review specifically
reports on the ostracods of the northern Western
Ghats including the ‘rocky outcrop’.
Methods: Sampling was carried out in eight different sites present on
hilltops including six forts of the northern Western Ghats from 2008–2012
(Fig. 1; Table 1). Three sites were
on ‘ferricretes’ type of outcrops and five sites were
on ‘basaltic mesa’ where there are hill forts (Watve2013) (Images 1 a,b). Mapping of the sites was carried out
using DIVA-GIS 7.5, while geographic data were obtained using handheld GPS and
Google Earth (http://earth.google.com).
In
our study, qualitative samples for ostracods were
collected using a circular plastic frame hand net (diameter = 15cm, mesh size
150μm). The net was swept
through disturbed sediments of shallow water bodies and through the aquatic
vegetation. Samples were collected
in 100ml plastic containers and fixed in the field using 5% formaldehyde. In the laboratory, samples were washed
under tap water using the same net and preserved in 70% ethanol. Ostracods were
separated under a stereo binocular microscope (Magnus MS24) using
micropipettes. Soft part
dissections and mounting of dissected appendages were done on a slide
containing a drop of polyvinyl lactophenol tinted
with lignin pink. Detailed
observations were made under a compound microscope (Olympus BX40). Valve details were studied under a JEOL
Analytical Scanning Electron Microscope. The ostracod genera were preliminarily
identified using Victor & Fernando (1981). For further confirmation of genus and
species identifications we consulted the original papers describing the taxon
for the first time and as many redescriptions of the
same taxa by other authors. In all,
we consulted around 50 publications and citing them all here is beyond the
scope of this Note.
Results and Discussion: Our study carried out from 2009–2012 revealed the presence
of 17 species of ostracods in various localities
(Tables 1, 2). Deb’s (1972, 1983)
collections were mainly from the Ajinkyatara Fort
area and the Tableland of Panchgani; her work
reported only six species.
Ostracods from ferricretes were reported by Deb (1972) for the first time
with the description of a new species Stenocypris krishnakantai; later on this species (Image 2a) was
assigned to the genus Chrissia (Victor &
Fernando 1979). We found
this species at the type locality, AjinkyataraFort. Other taxa reported by Deb
(1983) from the Tableland of Panchgani were Cypricercus indrani,Cypris elongata, Eucypris compressa,E. indica as new species and an unknown Sclerocypris sp. All these taxa were also found during
our study indicating the integrity of habitat conditions favouringtheir existence.
We
also found a species belonging to the genus Humphcyprisfrom only one representative sample collected from ChalkewadiPlateau. This is the first report
of this genus from Maharashtra and this species, pending further study could
probably be new to science.
Many
of the species described by Deb (1972, 1983), such as C. indrani,E. compressa, E.indica,
C. elongata, need taxonomic revision. The descriptions and diagrams provided
by the author are no longer adequate to confirm their generic identities and
the type specimens. Though
allegedly deposited in the Zoological Survey of India, Kolkata they are not
accessible for study. However,
based on the original descriptions and diagrams and by comparing the material
collected by us in the type localities, it is possible to assign these species
to other genera. Species of the
genera Eucypris and Cypricercusshould be assigned to one of the genera in the Strandesiagroup; some species may even require the establishment of a new genus in the
subfamily Cypricercinae (Battish2000; Shinde 2012).
Of
the 17 species of ostracods recorded here, 13 were
found in the pools on the basaltic mesa. Plesiocypridopsis dispar (Hartmann, 1964) (Image 2b) was found
almost on every plateau made up of basaltic mesa. Chrissia biswasi (Deb, 1972) is the largest (giant ostracod) species found on basaltic mesa. Some of the species
which were found commonly on basaltic mesa were not found on ferricretes. Sclerocypris sp. is a large taxon found only in the
pools formed on ferricretes rock while P. dispar is only known from basaltic mesa.
Stenocypris sohni described by Deb (1983)
was collected in a water body from Khopoli(Maharashtra); a very similar species was found in Visapurand Koraigad water pools on the basaltic mesas (Table
2). We are tentatively referring to
this species as Stenocypris cf. sohni Deb, 1983, pending further study.
The
number of species currently known from the northern Western Ghats is likely to
be an underestimation. An intensive
sampling effort, probably as a part of a larger program for studying freshwater
biodiversity is likely to bring more taxa to light. Our study on ostracodsindicates that the freshwater habitats on the rocky plateaus of the northern
Western Ghats are unique, holding a treasure of diversity, yet to be
discovered. Most of these habitats
are temporary, characterized by seasonal drying and filling cycles in a regular
frequency and their residents are adapted to these environmental conditions
with some of them even requiring the drought as a prerequisite for subsequent
resurgence (Williams 2006). Even
the ephemeral habitats of unpredictable reoccurrence formed during the monsoons
are microcosms of interest to investigate phenomena such as dispersal and
colonization of micro-and macroinvertebrates. All these habitats are under severe
threat from anthropogenic activities and their conservation requires attention.
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