Notes
on some rare and interesting Cladocera (Crustacea: Branchiopoda: Anomopoda:
Chydoridae) from Deepor Beel, Assam, India
B.K. Sharma1 & Sumita Sharma 2
1,2 Freshwater Biology Laboratory, Department of Zoology,
North-Eastern Hill University, Permanent Campus, Shillong, Meghalaya 793022,
India
Email: 1 profbksharma@gmail.com (corresponding author), 2sumitasharma.nehu@gmail.com
Date of publication (online): 26
January 2012
Date of publication (print): 26 January 2012
ISSN 0974-7907 (online) | 0974-7893 (print)
Editor: Humphrey Smith
Manuscript
details:
Ms # o2861
Received 05 July 2011
Final received 03 October 2011
Finally accepted 04 January 2012
Citation: B.K. Sharma & Sumita Sharma (2012). Notes on some rare
and interesting Cladocera (Crustacea: Branchiopoda: Anomopoda: Chydoridae) from
Deepor Beel, Assam, India. Journal of Threatened
Taxa4(1): 2304Ð2309.
Copyright: © B.K. Sharma & Sumita Sharma 2012. Creative Commons
Attribution 3.0 Unported License. JoTT allows unrestricted use of this
article in any medium for non-profit purposes, reproduction and distribution by
providing adequate credit to the authors and the source of publication.
Acknowledgements:This study is a part of the Ministry of Environment & Forests (Govt.
of India) sponsored project No. 22018-09/2010-CS (Tax) sanctioned to the senior
author. The
senior author is also thankful to Head, Department of Zoology, North-Eastern
Hill University, Shillong for necessary facilities. We
wish to thank our reviewers for their valuable comments and suggestions.
Abstract: Plankton samples collected from Deepor
Beel, a Ramsar site of India, during August 2008ÐJuly 2010, revealed six
rare and interesting Cladocera belonging to four genera of the family
Chydoridae. The globally important
elements include the AustralasianDisperalona caudata; the Asian Kurzia (Rostrokurzia) brevilabris;
the Indo-Malayan Alona macronyx; and Leydigiopsis curvirostris which is
known to occur elsewhere in North and South America. Kurzia (Rostrokurzia) brevilabris is a new record from India while Alona guttata tuberculata, A. macronyx andCoronatella anodonta are new records
from Assam. The documented species
are briefly diagnosed and comments are made on their distribution.
Keywords: Cladocera, India, Interesting species, Ramsar site.
Deepor Beel (91035ÕÐ91043ÕE
& 26005ÕÐ26011ÕN; 40km2; altitude
42m), an important floodplain lake of the Brahmaputra
River basin of northeastern India as well as a Ramsar site, merits considerable
significance for its biodiversity value (Sharma & Sharma 2008). Realizing this importance, the authors
undertook detailed limnological reconnaissance (August 2008ÐJuly 2010)
with special reference to faunal diversity and ecology of invertebrates in
general and zooplankton diversity in particular. As a part of our study on Cladocera fauna of this
interesting wetland, we came across six rare and interesting Cladocera of the
family Chydoridae, including four globally important elements namely Disperalona caudata,
Kurzia (Rostrokurzia) brevilabris, Alona macronyx and Leydigiopsis
curvirostris. In addition, one species is a new record from
India and two species are new records from Assam state. All the recorded species are identified
with comments on their distribution.
Materials
and Methods
Qualitative
plankton samples were collected monthly by towing nylobolt plankton net (No.
25) and were preserved in 5% formalin. The plankton samples were screened for sorting out different species which were mounted individually in a polyvinyl
alcohol-lactophenol mixture. Different species were identified following Smirnov (1971, 1996) and
Sharma & Sharma (2007, 2008). Photographs were taken with a Leica DM 1000 image analyzer. The voucher specimens are deposited in
the holdings of the Freshwater Biology Laboratory, Department of Zoology,
North-Eastern Hill University, Shillong.
Systematic
list of the recorded species
Superclass:
Crustacea
Class:
Branchiopoda
Superorder:
Cladocera (sensu strictu)
Order:
Anomopoda
Family: Chydoridae
Subfamily: Chydorinae
1. Disperalona
caudata Smirnov,
1996
Subfamily: Aloninae
1. Alona guttata
tuberculata(Kurz, 1875)
2. A. macronyx (Daday, 1898)**
3. Coronatella
anodonta(Daday, 1905)**
4. Kurzia (Rostrokurzia) brevilabris Rajapaksa & Fernando, 1986*
5. Leydigiopsis
curvirostrisSars, 1901
* New record from India; ** New record
from Assam
Taxonomic
notes
Disperalona caudata Smirnov, 1996 (Images
1Ð2)
Characters: Valves longitudinally striated; posterior
dorsal angle expressed and posterior ventral angle rounded. Rostrum long, pointed and ventrally
directed. Head
shield with two main head pores and two small pores between them. Antennule reaching half-wayto the tip of rostrum. Postabdomen relatively elongated, with a distinct dorso-distal corner
and pre-anal angle not distinct. Postabdomen with 14 anal
teeth, proximal teeth small. Claw with two basal spines; second basal spine smaller
than the diameter of the base of claw.
Alona guttata tuberculata (Kurz, 1875)
Characters: Head shield and valves with
characteristic rounded pits. Labral plate rounded. Postabdomen with 8Ð10 anal
spines; pre-anal corner projecting; distal dorsal end projecting beyond base of
claws. Claw
with a basal spine and with setae on its concave margin.
Distribution: Meghalaya.
Coronatella anodonta(Daday, 1905) (Images 3-4)
Characters: Body oval, with maximum height in
middle. Head shield and valves
with distinct tubercles; postero-dorsal and postero-ventral corners of valves
rounded. Antennules
almost reaching apex of rostrum. Ocellus situated halfway between eye and apex of rostrum. Labral plate rounded, without any
denticle on its anterior margin. Postabdomen with anal
denticles and lateral setae. Claw with a basal spine.
Distribution: Meghalaya and Rajasthan (?).
Alona macronyx(Daday, 1898) (Images 5-6)
Characters: Body oval, with maximum height before
its middle. Valves with lines and dots; postero-dorsal and
postero-ventral corners rounded; ventral margin slightly concave. Antennules not
reaching apex of rostrum. Ocellus smaller than eye and
situated near to it. Labral plate with convex anterior margin and
truncate apex. Postabdomen narrowing distally and with an
incision at the base of the claws; with 12-14 large marginal anal denticles,
distal margin of post-abdomen with a small denticle. Claw with a basal
spine nearly half as long as claw.
Distribution: Meghalaya and Madhya Pradesh.
Kurzia (Rostrokurzia) brevilabris Rajapaksa & Fernando, 1986 (Images 7Ð8)
Characters: Body oval and compressed;
postero-ventral corner of valves rounded. Valves marked with longitudinal lines; marginal setules along
postero-lateral corner and sub-marginal setules on posterior margin
subequal. Rostrum elongated. Ocellus about half
the size of eye and situated close to it. Three connected head pores; medial pore relatively smaller;
lateral pores minute. Antennules
elongated; only three longest aesthetasces reaching tip of rostrum. Labrum
strongly reduced; labral plate with rounded anterior margin. Post-abdomen elongate; distal corner
with a narrow lobe projecting beyond claw; dorsal margin slightly recurved with
10-14 short denticles followed by 3Ð5 groups of minute spines. Claw elongated, with setules; basal spine short and with setules at its base.
Leydigiopsis curvirostris Sars, 1901 (Images 9-10)
Characters:Body with maximum height
in the middle. Postero-dorsal and postero-ventral corner of valves
rounded. Ventral margin of valves
protruded before the middle; entire ventral margin with concentric rows of dots
and with setae which continue along posterior margin
in a row of fine hairs. Rostrum very long and curved posteriorly. Distance from apex of rostrum to apex
of antennule nearly twice the length of antennule. Head-shield with two broadly connected main head pores and
two small pores close to them. Plate of labrum triangular and with slightly pointed apex. Ocellus about as
large as the eye. Postabdomen large; its dorsal
margin distinctly convex and distal to the anus; distal end of postabdomen
rounded. Pre-anal corner distinct with double row of 16Ð20 anal
denticles, decreasing in size proximally and a row of lateral spinules on each side . Claw large, with setae on the concave margin and with
a small basal denticle.
Remarks
Six
species of rare and interesting chydorid Cladocera are reported from Deepor
Beel. These include four globally
interesting elements viz., the Australasian Disperalona
caudata, the
Asian Kurzia (Rostrokurzia) brevilabris and the Indo-Malayan Alona macronyx, whileLeydigiopsis curvirostris is known elsewhere only from Brazil and
Nicaragua.
Kurzia (Rostrokurzia) brevilabris is an interesting addition to the Indian
Cladocera. Originally described
from Thailand (Rajapaksa & Fernando 1986), this species is also known from
Sri Lanka and Philippines. Our
present report from northeastern India, therefore, merits biogeographic
importance for extension of its range within the South Asian region. Hudec (2000) dealt with five known Kurziaspp. and proposed their subgeneric differentiation into Kurzia sensu strictuand Rostrokurzia. K. (Rostrokurzia) brevilabris is a member of the latter. This sub (tropical) Asian species can
be distinctly differentiated from other members of this genus by its diagnostic
reduced labrum.
Disperalona caudata, another globally important species, was
described from Mudginberri Lagoon, Kakadu National Park,
Australia (Smirnov 1996). Sanoamuang (1998) reported it from
northeastern Thailand as its first record from Asia. Sharma & Sharma (2007) reported D. caudatafrom two floodplain lakes (Deepor and Raidong beels) of the Brahmaputra River
basin, Assam extending its distributional range to the Indian
subcontinent. This Australasian
species depicts an interesting link between the cladoceran fauna of
northeastern India, Southeast Asia and Australia. Further, it is known from India, to date, from the state of
Assam only.
Leydigiopsis, a very rare genus, was described from
Brazil by Sars (1901) and until the end of 20th century, it was presumed to be distributed in South and Central America
only (Sinev 2004). In addition,
Sanoamuang (1998) examined its single specimen from Kalasin province of
northeastern Thailand but could not ascertain species status. Sinev (2004) categorized this genus to
be insufficiently studied and remarked on the unclear status of Asian Leydigiopsis.
Sharma & Sharma (2007) extended its distributional range to the Indian
subcontinent based on an earlier report of L. curvirostris in Deepor Beel. The present study
re-affirms its occurrence, restricted to the Assam State only. We believe that disjunct occurrence of
this chydorid of North American origin in India may represent an example of its
introduction by man and thus deserves further analysis.
The
Indo-Malayan Alona macronyx is a new record from Assam. The first Indian report of this species
referred to Indialona jabalpurensis, a new species described from Madhya
Pradesh by Rane (1983), which was considered as a synonym of A. macronyx (refer
Rajapaksa & Fernando 1987; Sharma & Sharma 1990). This species was recorded for the first
time from northeastern India from Meghalaya (Sharma 2008), and our report
further extends its distribution to the adjoining state of Assam. Alona guttata
tuberculataand Coronatella anodonta are new records from Assam; the latter is
recently observed from the Nokrek Biosphere Reserve of Meghalaya (Sharma &
Sharma 2011) while Sharma (2008) reported the former again from Meghalaya. These two taxa are, hence, known to
date only from the northeastern region of India
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