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The Cladocera, commonly termed as the 'Water Fleas,' are small, mostly microscopic animals and their body size generally ranges between 0.2 'mm to 3.0 mm. They comprise one of the primitive group of lower Crustacea and represent ah order of the sub-class Branchiopoda to which the general name of Entomostraca was formerly applied. The 'other orders included in this sub-class are the Anostraca, Notostraca and Conchostraca and these are often grouped as Phyllopoda. Among these, the cladocerans are more nearly related to the bivalved Conchostraca. However, their relationship with other groups of the microcrustaceans i.e., Copepoda, Ostracoda and Cirripedia is somewhat remote.
Cladocera are characterised by their two-branched antennae which function as the main swimming organs. The members of this group exhibit considerable variations in their general structural plan and behaviour. There is no single genus so generalised as to serve typical of this order although a broader information about their morphological details is provided by the genus Daphnia. In view of notable structural differences, the cladocerans are often grouped, by some authors, into two contrasting subdivisions i.e., the Calyptomera and Gymnomera.
In the former, the body and limbs (thoracic legs) are enclosed in a bivalved carapace while the head projects; these primarily feed on microscopic algae and fine detritus either by filtering the water or by rasping the surface of plants etc. On the contrary, in all the Gymnomera only brood sac is covered by carapace; these are predacious and feed on other entomostraceous crustaceans and rotifers.
These organisms exhibit an interesting life cycle. Natural cladocetan populations are mostly predominated by occurrence of parthenogenetic females or amictic females. Individual brood-size reflects considerable variations in different families and embryogenesis is accomplished within brood-sac of the primarous females. Sexual or mictic females are noticed only during certain parts of the year and often coincide with appearance of the males.
The males are known for many species; these are generally smaller than females and can be differentiated by their antennules, shape of postabdomen and modified fust leg. Sexual fertilization results in the production of mictic eggs which are covered over by thick chi$ous cases or epbippia. These are also called 'resting eggs' as they nonnally undergo a period of dormancy before hatching into juveniles.
The members of this group are primarily found in almost all sorts of fTeshwater ecosystems while species of only three genera i.e., Podon, Evadne and Penilia are known to be truly marine. Lentic environments harbour wider diversity and abundance of the cladocerans than the lotic biotopes. However, the significance of their occurrence and associations in streams is recently emphasized by Vila (1989). A-large number of species particularly belonging to the families Macrothricidae and Chydoridae inhabit littoral weedy margins of laks and ponds. A few taxa (Alona quadrangularis and Drepanothrix) live near the mud, although not specially adapted to this mode of life. The genera Ilyocryplus and Monospilus are structurally adjusted to the benthic zone; these forms may also swim but more often scramble on the bottom pulling with their antennae and pushing with the postabdomen. The species of Moina are commonly found in muddy pools though not exclusively confined to these habitats and some species of this genujs are reported to occur in saline lakes. Dephnia species are invariably noticed in ephemeral pools, small ponds and lakes. Limnetic cladoceran communities of inland lakes are generally comprised of species of Daphnia, Diaphanosoma, Ceriodaphnia, Bosmina and Moina.
Chydorus sphaericus is commonly encountered in planktonic as well as littoral samples. Certain cladocerans i.e., Sida crystallina and Ophryoxul gracilis exhibit intermediate character between the littoral and limnetic forms. Planktonic taxa of this group are usually transparent and nearly colourless while those found in the ponds, ditches or in the weedy margins of larger water bodies are often coloured yellowish, brownish or reddish. In addition, the members of this order are known to inhabit subterranean ground waters, dampened mosses and even the wet tree trunks covered by the Bryophytes.
The studies on taxonomy and distribution of these organisms have drawn notable attention since they were first described in the 18th century. Even though, several species reflect cosmopolitan distribution, one of the current problems in this group is to establish their equivalence and to ascertain the occurrence of such cognate species reported from distant geographical localities often transgressing continents. Attempts made to sort out equivalence to non-equivalence of species reported from different parts of the world led to a strong debate for rethinking on 'cosmopolitan' distribution of various taxa and their biogeographical significance.
Investigations on ecology and production of these microcrustaceans draw attention in light of changes in their community structure coupled with seasonal and long-term environmental changes, vertical distributional patterns,*phenotypic changes associated with cyclomorphosis and effect of predation, prey-avoidance mechanisms, microaggregatioDS, species associa~ons and interesting life cycle strategies involving alternation of parthenogenesis and gamogenesis and production and hatching of resting eggs.
The cladocerans fonn an integral link in an aquatic food-chain. They contribute significantly to biological productivity and energy flow in aquatic ecosystems partly because of their rapid turn¬over rates, metabolism and capability to build up substantial populations within short time-intervals and partly because a large number of species (filter-feeders) are dependent on detritus and autotrophic producers. They invariably comprise an important fraction of Zooplankton in lentie environments and coastal waters.
Their frequent abundance in the littoral microinvertebrate commuflities in lakes and ponds imparts them greater ecological importance. The signifICance of these organisms as food for both fry and adult fish was frrst indicated by Forbes (1883) and since then, this role has been emphasized by innumerable aquatic biologists. Analysis of gut contents of commercially important and culturable species of fishes has indicated their contribution upto 90¬95% by volume and this lead to their intensive culture as supplementary food in various aquaculture practices.
Varioos species of the cladocerans are regarded as valuable bio-indicators of water quality. These organisms have also been increasingly used in environmental toxicological studies, and bioassay experiments. In addition, they have been utilised as experimental models in ecological, ecophysiologica1, embryological and population genetics investigations.
The Cladocera in general and members of the family Chydoridae in particular are well known to be 'guide-forms' in establishing the trophic and developmental history of ancient lakes and reservoirs especially in the Quarternary epoch as their exoskeletal remains are well preserved in the sediments. In such endeavoures, the knowledge of composition and distribution of extant species is useful to resurrect palaeolimnological conditions.
Various schemes depicting classification and relationships of Cladocera were proposed earlier by Sars (1865), Gerstaecker (1866), CaIman (1909) and Eriksson (1934). these were briefly reviewed by Brooks (1959) who recognised only eight families, to whicb three more families have been added. These are, Sididae Baird, 1850; Daphniidae Straus, 1820; Moinidae Goulden, 1968; Macrothricidae Norman and Brady, 1867; Chydoridae Stebbing, 1902; Bosminidae Sars, 1865; Polyphemidae Baird, 1845; Leptodoridae Lilljeborg, 1861; Podonidae Mordukhai-Boltovskoi, 1968; Holopedidae Sars, 1865; Cercopagidae Mordukhai~Boltovskoi, 1968.
The cladocerans were studied and described by amateur and professional biologists from different continents of the world since the 18th century. However, studies on these microcrustaceans from India date back to the later half of the 19th century and various works relating to taxonomy disttibution, ecology and biolo~y from this country are detailed.
This peri- merely marked the beginning of faunistic study on freshwater Cladocera. Baird (1860) dealt with the description of Daphnia newport; based on the material collected by Rev. Hislop from Nagpur city in Maharashtra State.
During this pre-independence period, Gurney (1906, 1907) reported 22 species on the basis of samples collected by Dr. Annandale from Calcutta and its environs (deposited in the Indian Museum holdings) and also from Lower Bengal and Chakradharpur in Chotanagpur region of Bihar State. Following this, Daday (1911) described one new species from Bangalore from the material sent by Dr. Annandale.
However, rust study on this group in Zoological Survey of India was undertaken by Dr. R.B.S. Sewell (former Director, ZSI) in 1934 who reported eight species of cladocerans in his publication on 'The Fauna of Salt Lakes, Calcutta' Subsequently, Sewell (1935) gave an account of eleven species from the Indian Museum tank, Calcutta. Important earlier taxonomic information resulted from the collections by the Yale North India Expedition, from various localities in Punjab (parts now in Pakistan), Ladakh, Kashmir and Nilgiri Hills in south India. This material was examined by Brehm (1936) and Brehm and Worterek (1937), who dealt with 35 species and two unidentified species.
As mentioned above, the contributions during'this period were relatively few and primarily referred to taxonomy of freshwater cladocerans. Even the study from brackish ecosystem of the Salt Lakes (Sewell, 1934) resulted in taxa which usually occurred in freshwater environs.
Earlier phase of this period i.e., from 1948-1970 reflected only marginal increase in taxonomic contributions which originated from widely scattered localities. Brehm (1950) examined collections from Naga Hills (Nagaland), Bihar, Simla Hills (Himachal Pradesh), Madhya Pradesh and West Bengal and reported only nine cladoceran species. In another paper, Brehm (1952) described a new species of the genus Diaphanosoma from Bombay. Brehm (1953), subsequently, presented an account of 23 species based on his widespread samples from Nepal, Sikkim, West Bengal, Maharashtra, Andhra Pradesh, Uttar Pradesh, Karnataka, Tamil Nadu and "Pondicherry. He also dealt with two species of marine cladocerans i.e., Evadne tergestina and Penilia avirostris from Cochin and Malabar coasts.
In addition, Brehm (1963) examined two species from the river Yamuna at Delhi (material sent by Dr. V. Ganapati). Biswas (1964a, 1966) described one new species each of the genus Latona and Chydorus respectively from Rajasthan. Further, Biswas (1964b) studied ZSI collections (obtained between 1907-1916) from Simla Hills and samples collected by the Swiss Entomological "Expedition (1916) from NEFA (Kameng Division). Petkovski (1966) examined Dr. Ganapati's collections from Ajwa reservoir and Nimeta Water works, Baroda city (Gujarat State) and documented eleven species including the cescription of I ndialona ganapati. This was followed by the contribution to the cladoceran fauna of Kashmir by Das and Akhtar (1970).
Information about the occurrence and ecology of cladocerans from the east coast was presented by Prasad (1954), Muthu (1956), Krishnamurthy (1967) and Rajagopal (1967) while similar studies from the western coast were undertaken by George (1958), Mukundan (1967) and Alfred (1970). These contributions referred to only two marine species as documented earlier by Brehm (1953).
Ecological investigations of freshwater ecosystem were initiated ~ter 1960. Michael (1962) made observations on seasonal events in a natural population of Ceriodaphnia cornuta in a fish¬pond at Barrackpore (West Bengal). Krishnamurthy (1967) and Parabrahman et al., (1967) dealt with population ecology of Moina dubia from sewage oxidation and stabilization ponds. Vijayaragavan (1967) commented on some ecological relationships of 'cladocerans while Vijayaragavan (1970) analysed seasonal events in a natural population of Daphnia cannata in relation to ecological factors.
In addition, studies on comparative ecology of fish-ponds as Delhi (George, 1966), zooplankton ecology in a fish-pond at Barrackpore, West Bengal (Michael, 1969), limnology of S ukhna Lake, Chandigarh (Vasisht, 1968) and observations on plankton ecology in fISh-ponds at Chandigarh (Vasisht and Dhir, 1970) contributed information to cladoceran ecology from freshwater biotopes.
Systematic contributions during 1971-1980 nearly doubled than the preceding decade and resulted in important information relating to species composition of freshwater Cladocera in this country. Biswas (1971) examined 41 species from Rajasthan. The contemporary publication of Nayar (1971) resulted in only 18 species from this state. Michael (1973) gave an account of species occurring in and around Madurai (Tamil Nadu). Yousuf and Qadir (1975) dealt with seven species from Malpur Sar and Qadir and Yousuf (1977) recorded four species from Beehama spring iIi the Kashmir Valley. Referring to North-Eastern India, PatH (1976) gave a list of 17 species from Meghalaya and Manipur while Biswas (1980) studied 24 species from the states of Assam and Meghalaya. The cladocerans found in water bodies in and around Bhagalpur (Bihar) were studied by Nasar (1977). Sharma (1978) listed 34 species from lower 'Bengal region of West Bengal. Michael and Hann (1979) while dealing with resurrection of Chydorus reticulatus and its relationship with C. ventricosus referred to collections of Prof. D.G. Frey (Indiana University, USA) from
Trivandrum (Kerala) and commented on the Indian synonyms of this chydorid. Rane and Harshey (1979) reported Latonopsis /asciculata from Madhya Pradesh. In addition, Michael and Sharma (1980) dealt with the fast report ofD unhevedia serrata from India based on Prof. Frey's material from Madras and Ooty lake in Tamil Nadu.
Taxonomic information from backwaters was restricted to the description of Alona taraporevalae by Shirgur and Naik (1977) from Back Bay opposite" Taraporevala Aquarium, Bombay. However, a number of investigations dealt with ecology of marine cladocerans. Similar contributions from the east coast were made by Kaliyamurtby (1975), Santhanam et al., (1975) and Sundarraj and Krishnamurthy (1975); the studies from the west coast were those of Dellacroce and Venugopal (1972), Nair and Trainer (1972), Menon et al.• (1972), Pillai and Pillai (1975) and Goswami et al., (1977).
A good number of studies related to ecology of freshwater cladocerans during 1971-1980. Mitta and Thaicurtha (1973) conducted toxicological experiments involving the control of l)aphnia sp. by copper sulphate treatment Santharam et al., (1977) studied micro aggregation ofDaphnia carinata under laboratory conditions and commented on important causative on polymorphism of Daphnia cannata in a pond near Madurai (ramil Nadu).
Qadri and Yousuf (1968) analysed the influence of physico-chemical factors on the seasonality of cladocerans in Lake Manasbal (Kashmir). Additional synecological information on this group resulted from various general Umnologi~ investigations from the states of Orissa (Saha et. al.• 1971), West Bengal (Moitra and Mukherjee, 1972; lana, 1973, 1976, 1979; MandaI, 1976, 1980), Bihar (Nasar and Dutta-Munshi, 1974; Nasar, 1977), Haryana (Vasisht and Sharma, 1975), Madhya Pradesh (Mathew, 1977), Kamataka (Prasadam, 1977), Tamil Nadu (Prabhavathy and Sreenivasan. 1977) and Kashmir (Zutshi et al., 1980).
The period between 1971-1980 included only nine publications relating to various aspects of biology of freshwater cladocerans i.e., longevity, instar durations, egg production, growth and embryonic development etc. Majority of these studies dealt with tropical species from Tamil Nadu.
The mentioned aspects were examined in Dephnia cannata (Navaneethakrishnan and Michael, 1971), Simocephalus acutirostratus (Murugan and Sivaramakrishnan, 1973), Moina micrura (Murugan, 1975a), Ceriodaphnia cornuta (Murugan, 1975b) and Scapholeberis kingi (Murugan and Sivaramakrishnan, 1976). In addition, Murugan (1977) deal with hatchability of parthenogenetic eggs of SimpcephaJus acutirostratus cultured in artificial media. In-virto development of Daphnia carinata was examined by Murugan and Venkatamman (1977) while Job and Venkataraman (1989) studied •the effect of temperature on development, growth and egg production in this species. Besides, observations on the biology of a subtopical population of the male of Daphnia lumholtz; were made by Das et al., (1980) while only two publications i.e., Bhannot and Vass (1976) and Nandy et al., (1977) referred to mass culture of Daphnia carinata and D. lumholtzi respectively during this period.
The last decade (1981-1990) covered under this resume reflected significant increase in systematic contributions; the number of publications increased nearly four times than the preceding decade. In the beginning of this period, Battish (1981) dealt with species of the families Chydoridae and Macrothricidae from Panjab State. First account of head pore morphology of 20 chydorid species from West Bengal was provided by Sharma and Tiwari (1981). The works of PatH and Gouder (1982, 1988) and Raghunathan (1988b) dealt with the fau'na of Karnataka.
Taxonomic information from Tamil Nadu was supplemented by the studies undertaken by Raghunathan (1983), Venkataraman and Krishnamurthy (1984a, 198~b, 1984c, 1984d) and Judec (1977) while a couple of other publications from this state (Venkataraman and Krishnamurthy, 1989; Venkataraman, 1990a- 1990b) related to ultrastructure (SEM studies) of various taxa from this region. Ohrer systematic studies referred to the states of Madhya Pradesh (Saini and Singh, 1984; Rane, 1983a, 83b, 83c, 83d, 84a, 84b, 84c, 84d, 85a, 85b, 85c, 86a, 86b, 87; Rane ,and Jafri, 1990), Kashmir (Yousuf et. aI., 1983), Andhra Pradesh (Durga Pradesh et. al., 1985), West Bengal (Sharma and Sharma, 1985), Bihar (Ahmed and Singh, 1988) and Kerala (Raghunathan, 1989). Sharma and Sharma (1990) commented on taxonomic status and distribution of 12 new species and one new subspecies, described earlier by rane in a series of papers during 1983-1987, from Central India.
The redescription of the chydorid Alona taraporevalae was provided by Sharma and Michael (1983). Other important contributions dwing this period referred to latitudinal distribution of Cladocera in the Indian subcontinent (Fernando and Kanduru, 1984); review of taxonomic studies on Indian freshwater cladocera and remarks on their 'biogeography (Shanna and Michael, 1987) and synopsis of different studies on Indian Cladocem (Raghunathan, 1990). Recently, a monograph on the cladoceran taxa documented from this country was published by Michael and Sharma (1988) under Fauna of India Series.
In addition, three extra-Indian publications also included samples from this country was published by Michael and Sharma (1988) und.er Fauna of India Series. In addition, three extra-Indian publications also included samples from this country. Of these, Rajapaksa and Fernando (1986) while dealing with tropical species of the genus Kurzia commented on specimens from Calcutta (West Bengal) and Cochin. A note on the distribution of Alona macronyx by Rajapaksaand Fernando (1987a) dealt with the material from Jabalpur (Madhya Pradesh) while Rajapaksa and Fernando (1987b) examined specimens' of Notalona globulosa (= Indialona globulosa) from some localities in Orissa, Madhya Pradesh and 'ramil Nadu.
A fewer studies dealt with ecology of brackish water or marine cladocerans during tis decade. Raghunathan and Srinivasan (1983a) analysed cladocerans of the plankton community in ennore estuary, Madras and also made observations (Raghunathan and Srinivasan, 1983b) on Zooplankton dynamics and hydrographic features in this estuarine system. Balakrishnan Nair et. al., (1984) studied their ecology off Kadinamkulum backwaters while Dutta tit al., (1984) studied their ecology off Kadinamkulum backwaters while Dutta et al., (1986) made observations on effect 'of some physico-chemical parameter on the abundance of cladocerans in a brackish impoundment in West Bengal.
During 1981-1990, relatively more number of papers have dealt with ecology of these organisms from freshwater environs. Yousuf and Qadri (~981at 81b, 83) made synecological observations in Lake Manasbal; Yousuf et. al., (1983) studied composition and associations of crustacean communities of 17 water bodies in .the Kashmir valley and Yousuf et al., (1984) analysed summer and winter cladoceran communities of Lake Anchar, Kashmir. Venkataraman (1981) studied seasonal variations in natural population ofDaphnia carinata in relation to physico¬chemical and biological factors in a tropical temporary pond at Madurai.
Investigations on population dynamics, biology and production ecology of the chydorid, Chydorus sphaericus were made by Khan (1983a). Khangarot and Battish (1984) made observations on acute toxicity of copper to Daphnia lumholli. Sharma and Dutla GuPta (1984) commented on the effect of water temperature on cyclomorphosis in Daphnia lumholtzi. Energy budget of SimpcephaJus vetulus was worked out by Sharma and Pant (1984) while Sharma and Pant (1985a) referred to seasonal variations in species composition of Zooplankton (including 15 species of Cladocera) in two Kumaun Himalayan lakes .. In addition, Sharma and Pant (1985b) estimated oxygen consumption in SimocephaJus vetulus in relation to size, density and temperature; seasonal and population variations in this daphniid were studied sep~ately by Sharma and Pant (1985c). Manimegalai et. al., (1986) made• observations on helmet development in Daphnia cephalala in relation to predation under laboratory conditions.
Venkataraman and Krishnaswamy (1986) made laboratory studies on Anisops bouvieri predation and advantages of cephalic expansion in Daphnia cephalata and impact of predation on D. similis. Population. dynamics of Moina micrura and Ceriodaphnia cornula was studied by Murugan (1989, 1990) respectively. Additional ecological information relating to this group was provided in various routine limnological investigations from the states of Jammu and Kashmir (Vass and Zutshi, 1983; Balkhi el. ai., 1987; Va~s et. al., 1988, 1989), Maharashtra (Rao et. al., 1981), Karnataka (patil and Gouder, 1985), Uttar Pradesh (Khan et al., 1986) and Tripura (Bhattacharya and Saba, 1986, 1990).
So far only two publications from India referred to physiological studies in this group .. Tonapi et al., (1984) made preliminary observations on cardiophysiolog of the moinid, Moinodaphnia macleay;. In addition, Tonapi and Verghese (1987) studied cardio-physiological responses ofsome cladocerans to three common pollutants.
The studies on cladoceran biology registered considerable impetus during 1981-1990. Different observations on various biological parameters related to Daphnia carinata (Venkataraman, 1981), Leydigia acanthocercoides (Murugan and Job, 1982), Daphnia lumholtzi (Kanaujia, 1983; Sharma el. al., 1984b), Ceriodaphnia cornuta (Khan, 1983a), Diaphonosoma excisum (Jana and Pal, 1984a), Moina micrura (Jana and Pal, 1985c), Simocephalus vetulus (Sharma and Pant, 1985b; Kanaujia, 1987), Diaphanosoma senegal (Venkataraman and Krishnaswamy, 1985), Daphnia similis (Venkataraman and Krishnaswamy. 1986; Venkataraman tt. al.• 1986), Daphnia cephalata (Venkataraman and Krishmaswamy, 1986; Murugan and Moorthy, 1988)", Daphnia pulex (Vass and Raina, 1988), Simocephalus exspinosus (Shanna and Sharma, 1989) and Moina weismanni (Venkataraman, 1990c). Hatchability of parthenogenetic eggs of Daphnia lumhollzi in artificial media was examined by Sharma and Sharma (1982) while Sharma et al., (1984a) studied in-vitro development in this daphniid. Dutta Gupta and Maibam (1983) dealt with reproduction ofDaphnia magna in relation to influence of density and different concentrations of culture medium (Baker's yeast).
Jana and Pal (1983, 1984b,1985a) made observations on effeci of inoculum densities on population growth ofDaphnia carinala, Diaphanosoma txcisum and Moina micrura respectively while Jana and Pal (1985b) studied relative growth and egg production in Daphnia carinata undez different culture media.
Studies from Different Environs
The studies on Indian cladocera commenced in 1860 but remained neglected till the end of the last century. Subsequent progress till the first half of this century culminated in few taxonomic contributions. An increased attention. however, was focussed in the following decades' while considerable proliferation and intensification of research activities was noticed between 1971-1990. The literature on different aspects so far studied from India is scattered over about 175 references as outlined in the historical resume. Although the present review attempted to incorporate all the relevant information, non-inclusion of unpublished works or else some general ecological publications providing very ~ttle information on this group was unaviodable. Even taking all such contributions into a broader considerattion, only about 190 references could be compiled.
The cladoceran studies in this country began with researches on freshwater representatives and also subsequently received more attention than their counterparts from other aquatic ecosystems. A majority of the Indian publications, therefore, referred to the observations on various aspects of freshwater taxa from the mainland.
In the beginning, most studies on these microcrustaceans were faunistically oriented and this trend even continued to predominate till the more recent decades. As a result, about 75 references dealt with their sytematics from freshwater biotopes and these involved• widespread collections ranging from distant temperate localities from the northern boundaries of this country to those from tropical environs of the southern region. Although most investigations were based on scattered collections obtained by individual workers, some institutional surveys were undertaken by the Swiss Entomological Expedition (1916) from NEFA (Kameng division); the Yale North India Expedition (1932) from Ladakh, Kashmir, Punjab and Nilgiri Hills, and by Zoological Survey of India from Simla Hills (1907-1916) and Rajasthan (1957-1960) respectively.
The number of publications from different parts of India, however, did not correspond with overall taxonomic infonnation available because a notable fraction of these papers exclusively dealt with new taxa (most of ihem already synonymised) or new records of limited local distributional interest Besides, frequent atempts by various workers from this country to pigeon-hole their speciemens into already known taxa without recourse to the study of original descriptions or the reference collections aggrvated the magnitude of nomenclatural anomalies in our literature. Various existing ambiguties (till 1980) were, to a larger extent, resolved in a 'Fauna' volume on Indian Cladocera (Michael and Shanna, 1988) while a number of doubtful reports requiring gurther confmnation were treated as 'Incertae Sedis'
This monograph significantly augmented our knowledge regarding composition and distribution of freshwater cladocerans and provided suitable illustrations, keys and systematic notes on the examined taxa to serve as ready'reference for future workers. The continued indiscriminate descriptions of several new taxa from central India by Rane (1983-1987) aroused serious concern and their status was examined recently by Sharma and Sharma (1990).
Some general comments on the current status of Indian freshwater Cladocera (Sharnla and Michael, 1987; Michael and Sharma, 1988; Raghunathan, 1990) emphasized lacunae relating to State-wise or. regional faunistic surveys. An unbalanced picture of ' the number of species so far documented from various parts of this country (Map) conclusively corraborated with the above generalisation. The cladoeeran faunas of only six States i.e., Jammu and Kashmir, Rajasthan, West Bengal, Andhra Pradesh and Karnataka were apparently well explored. 'The lower number of species reported from many other areas was attributed to insufficient exploration and underline the need for the examination of additional collections in general and the detailed analysis of the littoral communities in particular.
The spccies inventories so far compiled from different regions of India required a critical review in light of questionable status of various reports. Further, most systematic contributions from the mainland were based on the collections from lentic freshwater habitats, only a couple of papers casually referred to the taxa from lotic environs while no information was available on species inhabiting subterranean waters or on those occurring in association with different moss types. The general faunistic nature of many earlier studies and lack of details of the ecosystems sampled or their macrophytic associations (if any) was 'the main handicap to present a synthesis of cladoceran diversity in various habitats. Comparative morphotaxonomic studies on populations from different parts of this country were altogether lacking.
The SEM studies comprised a valuable adjunct to classical cladoceran taxonomy but such obeservations on the Indian taxa were confined to some recent publications by Venkataraman and Krishnaswamy (1989) and Venkataraman (1990a, 1990b). Although earlier publications routinely commented on the occurrence of reported species in different states, only a few papers (Fernando and Kanduru, 1984; Sharma and Michael, 1987) analysed biogergraphicaI patterns in relation to the latitudinal distribution of freshwater cladocera from this country. In addition, studies on karyotaxonomy and those involving application of biochemical methods to seggregate sibling species complexes presented a challenging task for future workers on this group.
The brackishwater ecosystems remained very poorly surveyed faunistically except for few reports by Sewell (1934), Shirgur and Naik (1977) and Sharma and Michael (1983). The infonnation o.n the cladoceran ecology from these environs was confined to the observations in the Hughli-Malta Estuary (Shetty et al., 1961), Ennore estuary (Raghunathan and Srinivasan, 1983b) and in a brackishwater impoundment in West Bengal (Dutta et al., 1986). In addition, only one paper (Shirgur and Naik, loco cit.) referred to the biology of Alona taraporevalae which was described by these authors from a Back bay at Bombay.
Referring to marine cladocerans, the sole taxonomic report was that of Brehm (1953) although various ecological investigations undertaken at different places along the eastern and western coasts reported on the occurrence and seasonal abundance of marine taxa. However, so far only three species of these organisms i.e., Penilia avirostris, Evadne tergestina and Podon sp. were documented from the Indian coastal waters. Even though, the cladocerans were reported to comprise only a sub-ordinate group of marine Zooplanktonic communities (Go~wami et al., 1977), many workers from this country noticed frequent swarms of the former two species fro~ the Gulf of Mannar, Madras coast, Porto Novo waters, Cochin backwaters and Kadinamkulam backwaters. The significance of these swarms in relation to the coastal pelagic fishery was indicated by Mukundan (1969) and Alfred (1970).
The distant insular freshwater and marine ecosystems of the Andaman and Nicobar islands and Lakshadweep Archipelago still remained unexplored faunistica1ly and ecologically with reference to their inhabitant cladoceran communties. Some collections from freshwater biotopes of the former group of islands are currently being studied at Shillong while studies in these habitats are being initiated at Port Blair regional station of the Zoological Survey of India.
The investigations one ecology of freshwater cladocerans deserved special mention as they have drawn a notable attention. The first refemce on seasonal Occultence of these organisms in a freshwater tank was made by Sewell (1953) but serious studies on this aspect were, however, initiated by Michael (1962, 1969) and George (1966). A majority of these contributions resulted during the last two decades covered under this review.
A number of limnological investigation from various parts of this country invariable commented on the seasonal abundance and succession of the cladocerans as an important dominant or subdominant group. On other hand, ecological studies exclusively relating to these organisms were limited to about 25 references. Various earlier investigations largely dealt with planktonic cladoceran communities while litto,al taxa remained primarily ignored. Amongst the scattered observations undertaken from different states of India,a good number of references were from the fish-ponds in West Bengal and some lakes in Kashmir valley while only a few publications related to cladoceran ecology from the lotic ecosystems.
The reviewed literature indicated still insufficient information on synecological studies in general and also lacunae on particular aspects such as long-term observations on changes in species composition, vertical distributional patterns, population dynamics, growth and production, cyclomorphosis, energy budget, toxicological experiments and community structure in relation to eutrophication, effects of fertilization and impact of invertebrate and vertbrate predation on species composition.
A notable number of publications (about 35 papers) dealt with different biological aspects of freshwater representatives. These observations were initiated by Michael (1962) but all other contributions resulted during the last two decades (1971-1990). A majority of these studies included laboratory observations on various life history parameters i.e., longevity, instar durations, growth, fecundity and embryonic development etc. The mentioned aspects have been far examined in ten species of the family Daphniidae, two species each of the families Sididae and Moinidae and one species of the family Chydoridae.
So far only two publications ref~rrcd to the biology of the males of Daphnia lumholtzi and Moina weismanni. The observations on the hatchability of parthenogenetic eggs cultured in artificial media were made in Simocephalus acutirostratus and Daphnia lumholtzi. A couple of studies, during the last decade, dealt with the effect of inoculum densities on population growth and reproductive potential and the influence of different culture media on general life-history parameters. The experiments on mass culture of Daphnia carinata and D. lumholtzi were firstly attempted by Bhanot and Vass (1976) and Nandy et. ai., (1977) while culture possibility of Daphnia pUlex in various culture media was recently explored by Vass and Raina (1988).
Estimation of Taxa
Out of eleven recognised families of this order, only nine families were so far reported from India. In analysing the composition and origin of the cladoceran fauna of this country, it is important to note that all the three phylogenetic stems of Cladocera (vide Smirnov and Timms, 1983) i.e., the Ctenopoda, the Anomopoda and the Gymnomera were represented. Among the Ctenopoda, 'rvhich separated from the main phylogenetic stem in' the remote past, only the members of the family Sididae were documented while the Holarctic Holopedidae were notably absent from India. The Gymnomera belonged to only threc of their total five families. Of these, the reported members of the Holarctic Lcptodoridae and Polyphcmidae wee confined to temperate environs of the northern latitudes in this country and the family Podonidae included some marine elements.
Turning to the Anomopoda, all the known families (Macrothricidae -Chydoridae -Bosminidae -Moinidae -Daphniid.ae) were present in Indian inland waters. the first two families of this series were claimed to be nlost similar to their Conchostracan ancestors (Freyer, 1968, 1974) and these mainly comprised of littoral and benthic forms.
In a more general sense, the presence of the families Leptodoridae and Polyphemidae differentiated the cladoceran fauna of India from other South-Asian coun~es (Table 1) and the Australian continent (Table 2). On the other hand, absence of the Holopedidae imparted it a different status from the fauna of Asia, Europe, North America and South America (Table 2). The occurrence of various mentioned Holarctic families assigned an intermediate character to Indian Cladocera in relation to the faunas of the northern and southern continents. such an overlap might be attributed to the wide range of environmental conditions prevalent in this country.
Among various families of Cladocera, Smimov (1971) differentiated four sub-families of the Chydoridae. However, Indian chydorid taxa belonged to only three sub-families i.e., Eurycercinae, Aloninae and Chydorinae. In addition, falnily Macrothricidae was represented by only two (Le., Macrothricinae and Ilyocryptinae) of the four recognised sub-families (Smirnov, 1976).
All the known genera of he families Daphniidae (Daphnia, Simocephalus, Scapholeberis, Ceriodaphnia), Bosminidae (Bosmina, Bosmino'psis), Moinidae (Moina., Moinodaphnia) and Leptodoridae (Leptodora) were represented in Indian inland waters. PolyphemiQae included only one genus (Polyphemus) while the family Sididae is represented by six out of its seven genera.
However, lower generic diversity was noticed in the families Macrothricidae and Chydoridae; the former was represented by only five of the known 17 genera and the chydorids belonged to 19 of the described 32 genera. In contrast to endcmic genera of these two families in the Holarctic region and Australasia, Indialona was the sole endemic genus noticed in the Indian fauna. Of many widespread genera of the mactrothricids and the chydorids (vide Smimov and Timms, 1983), only Sida and Eurycercus occurred in this country while some primitive genera were represented by Eurycercus and IlyocryplUS. AlLhough in view of inadequate collections from various regions of India, it might be premature to comment on distributional limits of different genera but Eurycercus, Leptodora, Polyphemus, Daphniopsis, Dadaya, Greptoleberis, Streblocerus, Indialona, Acroperus and Camptocersus were reported (Fernando and Kanduru, 1984; Sharma and Michael, 1987) to exhibit restricted distribution.
Total no. of species 109 58 64 39 55 46 131 No. of Endemics 7(?) 1 ? 2(?) 8(?) SOUTce of Data: Sri Lanka ..-Fernando (1980); Malaysia Smirnov and Timms (1983), Shanna aed Michael (1987); Philippines Smirnov and Timms (1983); Thailand and Nepal Shanna and Michael (1987); Indian subcontinent Fernando and Kanduru (1983), Sharma and Michael (1987).
The cladoccran taxonomy was stated (Frey, 1987) to be expanding explosively beyond the horizons percievcd or imagined a few years ago because of more recent discoveries of various sibling-species complexes and strong support to idea of non-cosmopolitanism of various taxa. Hence, an estimate of overall diversity in this group could merely be speculative although so far over 400 species of freshwater Cladocera were known to be described from different parts of the world. Information about the number of species documented by various workers from Indian inland waters varied marginally. Fernando and Kanduru (1984) examined 87 species from this country; Sharma and Michael (1987) and Michael and Sharma (1988) dealt with 93 and 87 species respectively; 97 valid species were recognised from the list given by Raghunathan (1990) while 109 species of freshwater cladocerans are compiled in this account.
The list of Indian Cladocera (109 species) appeared to be reasonably complete and corresponded well with 107 species reported from Africa. The cladoceran fauna of India reflected more species and generic diversity than other countries in this subcontinent and neighbouring South Asian faunas (Table 1).
Chydoridae, Daphniidae and Macrothricidae, in the stated order, comprised significant fraction of Indian Cladocera. The number of documented species of the first two families was broadly comparable with faunas of various parts of the world while family macrothricidae exhibited less species diversity when compared particularly with Asia, Australia, North America and South America. Commenting on the distribution of Daphnia, an important genus of the Daphniidae, Fernando (1980) states that usually one or two species of this gerius occurred in a country or region in the tropical belt and about 10 or more species in a temperate region.
This generalisation appeared to be valid concerning the occurrence of limnetic Daphnia spp. in tropical parts of this country but an overall report of 10 species from India broadly corresponded with other reports from Asia and Australia.
The limnetic cladoceran communties in alkaline inland waters in this country were invariably comprised of species of Daphnia. Ceriodaphnia, Moina and Diaphanosoma. Bosmina iongiroslris, however, was the most important planktonic member of this group in slightly acidic or nearly neutral waters particularly in North-Eastern India. In tropical parts of this country, Daphnia carinata, Cerio/daphnia cornuta, Moina micrura, Diaphanosoma sarsi and D. excisum occurred widely and often formed quantitatively important component of planktonic Cladocera; these also represented eurytopic and tropicopolitan forms. The rust three mentioned species were noticed to exhibit frequent swarms (microaggregations) in eutrophic water bodies in hot and arid zones of this country.
Based on presently available information on distribution of various species, the Indian freshwater Cladocera were comprrised of five groups in terms of their zoogeographical relationships. The first group-included some cosmopolitan species.
The third group comprised Palacarctic, Holarctic or other temperate species which also occurred in some parts of India. The disjunct distribution of some of these cladocerans might be due to their dispersal by bipolar migratory birds. In addition, their present restricted occurrence could be a relict of a wider distributional range in the past that changed by long-term fluctuations in the climatic conditions particularly during the Pleistocene glaciation (Berg, 1947).
The fourth group included Gondwanaland forms which were almost exclusively found in the southern continents (including India and Sri Lanka). Out of 24 such elements listed by Smirnov and Timms (1983), sixteen species were represented in India. Among these, Dadaya macrops was known to be distributed slightly beyond the Gondwanaland continents. In addition, Alona globulosa and Chydorus ventricosus were other species of this category documented from India. however, they were so far reported from South America and South Africa but not from the Australian continent
The fifth group included the endemics which were represented by Indialona ganapati, Alona tar'!-porevalae and Moina oryzae. Besides, Battish (1981) described three new species from Punjab i.e., Alona dhilloni, Camptocercus kapuri and Ilyocryptus bhardwaji while Leydigia ankammaraoi• was described (Durga Prasad et. al., 1985) from Andhra Pradesh; the specimens of these species need to be re-examined to ascertain their taxonomic status.
In addition, Rane (1983-87) dealt with the descriptions of 12 new species and one new subspecies from Madhya Pradesh in Central India and comments on their systematic validity were made recently by Sharma and Shanna (1990). The paucity of endemic taxa in the fauna of South Asian countries in general and the Indian Cladocera in particular was in notable contrast to the Asian fauna (24 endemic species) or that of various other areas of the world (Table 2).
Referring to overall composition, the cladoceran taxa occurring in inland waters of India appeared to be relatively more diversified than other studied South-Asian faunas. Further, the cladoceran fauna of this country included species belonging primarily to the mentioned flfSt four groups in comparison to its neighbouring countries wherein the documented taxa were restricted to ani y first three categories.
Marine taxa so far known from different parts of the world included eitht species of Penilia, Evadne and Podon and a subspeices of he family Bosminidae and 35 species of the superfamily Polyphemoidea. However, our knowledge of truely marine cladocerans from Indian coastal waters was very poor and included only three species i.e., Penilia avirostris (Family: Sididae) and Evadne tergestina and Podon sp. (both belonging to family Podonidae).
The cladoceran taxa so far documented from India belonged to nine families. Of these, the membets of eitht families i.e., Sididae, Dcphniidae, Moinidae, Bosminidae, Macrothricidae, Chydoridae, Leptodoridae and Polyphemidae occurred in inland waters in this country. The sididae also included one marine species while other reported taxa of this category belonged to the family Podonidae.
It was represented by nine species spread over six genera. Penilia avirostris, the sole marine element of this falnily, was often reported to exhibit swarms in various ecological studies from the eastern and western coasts of this country. Among other species, Pseudosida _bidentata and Latonopsis australis registered widespread distribution in this subcontinent and Sarsilatona serricauda (= Latonopsis fernandol) was reported only from Central India. The Holarctic and Neotropical Sida crystallina could be termed as a northern element. The genus Diaphanosoma included four planktonic species. Of these, D. excisum and D. sarsi occurred across the whole latitudinal range south of 32°N (Sharma and Michael, 1987). The distinct occurrence of D. senegal in different states of this country broadly indicated its wider distribution. Fernando and Kanduru (1984) regarded D. brachyurum to be a northern species but it was also reported from Madhya Pmdesh and Kamataka.
Little was known about ecology of Indian representatives of this family except for some observations' made by Yousuf and Qadri (1981a) and Qadri and Yolusuf (1983). Other published infonnation related to life history parameters of Diaphanosoma excisum in different culture media (Jana and Pal, 1948a) while Jana and Pal (1984b) studied population growth and reproduction of Diaphanosoma senegal under laboratory conditions. Some comments on epizoic associations of certain rotifers (Brachionus rubens and B. sessilis) on Diaphanosoma spp. were made by this author (Sharma, 1979, 1983).
The members of this family formed an important component of Indian Cladocera. It included 23 species and all known genera of the daphnids w'ere represented in qur inland waters. The genus Daphnia was comprised of Daphnia s. str., Ctenodaphnia and Daphniopsis and these were represented by four, Six and one species respectively. Of these, Daphniopsis tibetana and all species of Daphnia s. str. were restricted to> 24°N (Fernando and Kanduru, 1984). On the other hand, species of Ctenodaphnia were distributed in the Indogangetic plains and southwards. Daphnia carinata and D. lumholtzi occurred widely in water bodies ~n peninsular India vJhile D. cephalata andD. projecta appeared to be confined to the.extreme southern parts of this country. The presence of far few species of the genus Daphnia in the equatorial zone of this continent as compared to its more northern regions was elucidated by Fernando (1980) and Fernando and Kanduru (1984).
Interestingly, this generalisation could not be appl~ed to this author's fairly extensive collections from North-Eastern India (unpublished report). The paucity of Daphnia spp. in this' region, however, was in confrrmity with their occurrence in the neighbourin~ South Asian countries. In light of these observations, the distribution of different sp~ies of this daphniid might be attributed to far complex factors rather than mere latitudinal considerations.
The genus Ceriodaphnia was represented by seven species of which only cosmotropical C. cornuta was widely distributed in India while C. pulchella comprised a northern element as it was confmed to Kashmir and Ladakh. The other species exhibited disjunct occurrence-in different states of this country. The paucity of lim netic Ceriodaphnia spp. in North-Eastern India was again in agreement with those of tohber South Asian frunas. Simocephalus and Scapholeberis were represented by five and two species respectively.
Simocephalus vetulus, S. exspinosus and Scapholeberis kingi occurred widely; Simocephalus latirostris and S. serrulatus were documented from a number of states; Scapholeberis mucronata was reported only frOIm Madhya Pradesh while SimocephaJus acutirostratus occurred in Central India and southwards.
Different planktonic forms of Daphnia and Ceriodaphania invariably figured in various synecological or general limnological studies from this country and were reported to comprise quantitatively important component of cladoceran communities in len tic freshwater environs. Dephnia carinata, D. lumholtzi and Ceriodaphnia cornUllJ often exhibited swarms in eutrophic astatic water bodies in warmer parts of India. Some observations on autecology of Daphnia carinata were made by Vijayaragavan (1970), Santhar8111 el. al., (1977) and Venkataraman (1981) while Michael (1962) dealt with seasonal events in Ce~daphnia cornuta and population dynamics of this daphniid was analysed by Muregan (1990). Sharma and Pant (1984, 1985b, 1985c) studied energy budget, oxygen consumption and seasonal and populational variations in Simocephalus vetulus respectively.
A few toxicological observations on Daphnia spp. were undertaken by Mitra and Thakurtha (1973) and Khangaroot and Battish (1984). The studies relating to various aspects of cyclomorphosis in our-species of this genus were those by O'Brien and Vinyard (1978), Shanna and Dutta Gupta (1984), Venkataraman and Krishnaswamy (1986) and Manimegalia eta al., (1986). In addition, comments on some epizoic rotiCers on the planktonic daphniids were made by Sharma (1979, 1983).
The members of this family have received notable attention in various biological investigations from India and resulted in over 26 publications. Lite-history parameters have so far been studied in Daphnia carinata, D. cephalata, D. similis, D. lumholtzi, D. pulex, Ceriodaphnia cornuta, simocephalus acutirostratus. S. vetulus. S. exspinosus and Scapholeberis kingi. Murugan (1975b) and Sharma eta al.• (1984a) commented on the influence of latitudinal variations on fecundity in Ceriodaphnia cornuta and Daphnia lumholtzi respectively. The biology' of the male of the later species was worked out by Das eta al., (1981). Some other observations related to in-vitro development and hatchability of the parthenogenetic eggs of Simocephalus acutirostratus and Daphnia lumholtzi in artificial media. In addition, Dutta Gupta and Maibam (1983), Jana and Pal (1985a), Venkataraman (1986) and Venkataraman and Krishnaswamy (1986) studied the effect of different culture media on life-history parameters of Daphnia magna, D. cannata, D. similis and D. cephalata respectively. A few investigations (Bhanot and Vass, 1976; Nandy eta al., 1977; Vass and Raina, 1988) dealt with culture propects ofDaphnia carinata. D. lumhollzi and D. pulex.
This family was represented by five species of Moina and only one species of the genus Moinodaphnia i.e., M. macleayi. Moina oryzae, an endemic element. of this family was described by Hudac (1987) from a rice-fledl in Tamil Nadu. M. micrura was widely distributed in India, M. brachiata and M. macrocopa were reported from a number of states from this coUntry while M. weismanni was documented only from Gujarat and Tamil Nadu.
Moina micrura and M. brachiata were dealt with in many ecological investigations from India. The former appeared to be most common in eutrophic ponds, tanks and waste stabilization ponds; some observations on its population ecology in sewage waters were made by Krishnamurthy (1967) and Parabrahman eta al., (1967). Population dynamics of M. micrura was studied by Murugan (1989). Laboratory observations on the biology were undertaken in M. micrura (Murugan, 1975a) and M. weismann; (Venkataraman, 199Oc). In addition, Jana and Pal (1985a) analysed effect of inoculum density on growth, reproductive potential and population size in M. micrura while Jana and Pal (1985b) studied life-history parameters of the states species in five different culture media. Some comments relating to the rotifers epizoic on this moinid were made by Sharma (1979, 1983).
Both the known genera of this family (Bosmina and Bosminopsis) were present in our in~d waters. The former included two species i.e., B. longirostris and B. coregoni while another new species is being described from Tripura (prof. Bhattacharya: personal communication).
The latter genus was represented by Bosminopsis deilersi. Bosmina coregoni was so far reported only from Kashmir valley. Fernando and Kanduru (1984) commented that BosmlniJpsis deiiersi showed a more southern distribution from Sri Lanka to Mymensingh (Bangladesh) in this subcontinent while Bosmina iongirostris reflected a more northern distribution from Srinagar to Calcutta and the hilly areas, the Nilgiris and Coimbatore. however, this author's observations (unpublished data) extended the distributional range of the former species to North-Eastern India. Further, B. longirostris was observed to be most common and quantitatively important species of planktonic cladoceran commonties in different states of this region.
Ecological information on the documented species of this family remained practically neglected in this country except for the observations made by Yousuf and Qadri (1983) from Manasballake in Kashmir valley.
It included only eleven species belonging to two sub-families i.e"., Macrothricinae and Ilyocryptinae. Ilyocryptus bhardwaji comptrised the sole endemic element of this family. Macrothrix griJonlandica and Gurnaella rephaelis indicated restricted occurrence and they were so far reported only from Ladakh and Kashmir respectively. Fernando and Kanduru (1984) considered Grimaldina brazzai to be strictly an equatorial species occurring below 12°N; this, however, was also reported (Rane, 1984d) from Madhya Pradesh in Central India. Some ~omments on the ecology of the representatives of the Macrothricidae were made by Yousuf and Qadri (1983).
The chydoridae, the largest family of this order, also comprised the most dominant component of Indian Cladocera and included 55 species belonging to nineteen genera. Important taxonomic information on the chydorids examined from this country, however, was confined to fewer publications. This family included the members of three subfamilies in our inland waters i.e., Eurycercinae, Chydorinae and Aloninae.
Eurycercinae was represented by Eurycercus lamellatus which was so far documented from Kashmir (above 32°N). The report on the occurrence of a head shield of Eurycercus from Jabalpur in Central India was accounted to be carried by a river originating in cold regions of the Himalayas (Adholia, 1979) although such an explaination was unlikely to be feasible. Interestingly, a species of this genus was collected by this author (unpublished report) from a pond and a paddy-field from lower altitudes in Jaintia Hills (Meghalaya) in North-Eastern India; a detailed report of the status of this species, however, awaits population analysis.
The subfamily Chydorinae was represented by 22 species spread over seven genera. The cosmopolitan Chydorus sphaericus was distributed across the whole latitudinal range in this subcontinent. Alonella excisa, Chydorus eurynotus and C. venlricosus occurred widely. Pleuroxus trigone llus , P. laevis, Alonella nana, A. exigua and Dunhevedia crassa ciliocaudata were not noticed south of 22°N. Chydorus pubescens was reported only from Assam. Chydorus parvus, C. herrmanni, C. kallipygos, Dunhevedia serrata and Dadaya macrops could be regarded as southern elements of this subfamily.
The third subfamily (aloninae) included 31 species belonging "to eleven genera. alona taraporevalae, an interesting species, was described from a back bay at Bombay "though confmnation about its original habitat was still required. Other endemic elements of Aloninae were represented by Indialona ganapati, alona dhilloni. Camptocercus /capuri and Leydigia ankammaraoi; the frrst species was reported only form Gujarat and Madhya Pradesh. Acroperus angustatus appeared to be a northern fomi; Alona monacantlta tridentata and Leydigia australis ceylonica were restricted to southern parts of this country while Alona rectangula richardi, A. davidi punctata, Oxyurella tenuicaudis and Kurzia latissima were examined only from West Bengal.
Information on ecology of the cbydorids was primarily confined to the investigations by Yousuf and Qadri (1981b) and Yousuf et. ale (1984). Population dyqamics, biology and production ecology of Chydorus sphaericus was studied by Khan (1983a) while observations on life history parameters of Leydigia acanthocercoides were made by Murugan and Job (1982).
It was represented by single Holarctic species i.e., Leptodora kindti from Kashmir; its another report from Lower Bengal region of West Bengal (MandaI, 1980) was certainly questionable. Some comments on the ecology of this species were made by Yousuf and Qadri (1983).
This holarctic family was represented only by Polyphemus pediculus from kashmir. However, there was no information about its ecology from India.
It included two truely marine taxa i.e., Evadne lergestina and Podon sp. The former species was reported to exhibit swarms in various ecological investigations along the eastern and western coasts of this country: However, information on the ecology of Podon sp. was much limited.
Inspire of notable increase in the number of faunistic contributions during the last decade, only few workers are currently actively engaged in systema.tic studies on these organisms in India. Sharma and co-workers at the Department of Zoology, North-Eastern Hill University, Shillong are working on the cladoceran faunas of various states of North-East. In this connenction, extensive studies have been initiated (in collaboration with Dr. S. Sharma, ERS, ZSI, Shillong) on the samples collected from Meghalaya and Tripura under 'State Fauna' Series programme of the Zoological Survey of India. Sharma is also studying collections from the States of West Bengal and Orissa and samples from the Andaman and Nicobar islands. Shar~a is also working on the cladoceran fauna of Bihar in collaboration with Dr. R.K. Sinha ofPatna University. B. K. Sharma and R.G.
Michael continue to work on this group. Attempts are also being made to maintain national reference collections on Cladocera. Besides, taxonomic studies are being undertaken in Zoological Survey of India at its various regional stations.
Although routine limnological investigations invariably refer to the cladoceran communities but serious synecological researches on freshwater Cladocera are being carried out at North-Eastern Hill University, Gauhati University, Calcutta University, Kalyani University, Punjab University, Patna University, Aligarh Muslim University, Kashmir University and Kumaun University. The studies on certain aspects of biology are also in progress at some of the mentioned universities. The observations on the ecology of marine cladocerans are undertaken at National Institute of Oceanogmphy, Goa, Indian Oceanic Biological Centre, Cochin and in other marine laboratories.
K. Venkataraman, ZSI, M Block, New Alipore, Calcut~ -700 053 M.B. Raghunathan, ZSI, Western Ghat Regional Station, Kozhikode (Kerala) Sumita Sharma, ZSI, Eastern Regional Station, Risa Colony, Shillong S.G. PatH, ZSI, Western Regional Station, Pune
S.K. Battish, Department of Zoology, Punjab Agricultural University, Ludhiana, Punjab. [Taxonomy and ecology] Datta, Department of Zoology, University of Calcutta, 35, Ballygunge Circular Road, Calcutta, West Bengal. [Ecology of planktonic Cladocera] Murugan, Department of Zoology, Madura College, Madurai, Tamil Nadu, [Taxonomy, Ecology and biology]
B.B. lana, Department of Zoology, Kalyani University, Kalyani, West Bengal, [Ecology, Biology , Culture] A.A. Khan, &A. Haque, Department of Zoology, Aligarh Muslim University, Aligarh, Ultar Pradesh. [Composition and ecology]
C.K.G. Nayar, Department of Zoology, Christ College, Irinjalakuda, Kerala. [Taxonomy and ecology]
B.K. Sharma, &R.G. Michael, Department of Zoology, North-Eastern Hill University, Shillong -14, Meghalaya. [Systematics, biogeography, associations ecology, population dynamics, biology]
M.C. Pant, &P.C. Sharma, Department of Zoology, Kumaun University, Nainita, Uttar Pradesh. [Composition and ecology]
H.S. Vasisht, Department of Zoology, Panjab University, Chandigarh, Union Territory. [Composition and ecology]
K.K. Vass, Central Captive Inland Fisheries Research Institute, Barrackpore, West Bengal. [Ecology, biology and culture]
A.R" Yousuf, Department of Zoology, University of Kashmir, sri nagar, Jammu and Kashmir. [Composition and ecology]
F. Argentesi, Department A, J.R.C., Ispra, Italy. [population dynamics, mathematical modelling] R. Baudo, CNR Institution Italiano di Idrobiologia, Pallanza, Italy. [Ecotoxicology]
J .A.H. Benzie, Australian Institute of Marine Science, Townsville Queensland, Australia 4810. [Systematics and distribution] Chengalath, National Museum of Natural Sciences, Ottawa, Canada. [Systematics, distribution and ecology] de Bernardi, CNR Institute Italiano di Idrobiologia, 28048 Pallanza, Italy. [population dynamics, ecology and predation]
H.]. Dumont, Institute of Ecology, State University of Gent, B-9000 Gent, Belgium. [Taxonomy, distribution, dyn~ics] A. Duncan, Department of Zoology, Royal Holloway College, Surrey TW20 9TY UK. [Composition, ecology, population dynamics, production]
Fernando, C.H. Department of Biology, University of Waterloo, Waterloo, Ontario, Canada. [Composition, systematics and distribution of tropical Cladocera]
W,.T. Edmondson, Department of ~ology University of Washington, Seattle, Washington, USA. [Ecology, population dynamics and production]
Frey, Department of Biology, Indiana University, Indiana, Bloomington, USA. [Systematics and zoogeogrdphy of Chydorids, ecology, palaeolimnology]
Freyer, Freshwater Biological• Association, Ambleside, Westmorland, UK. [Systematics, functional morphology, adaptive Significance, ecology]
Goulden, Academy of Natural Sciences of Philadelphia, Philadelphia, USA. [Systematics, distribution evolution, ecology , palaeolimnology]
Green, School of Biological Sciences, Queen Mary College, London, UK. [Systematics, composition, associations, and ecology]
Gulati, Limnological Institute, Vijverhof Laboratory, Nieurwersluis, The Netherlands. [Feeding, ecology and population dynamics]
Hrbacek, Hekrova 820, Praha 4, Haje 14900 Czechoslovakia. [Systematics, disttibution, ecology competition and production]
Hebert, Department of Biology, Great Lakes Institute, University of Windsor, Windosor, Ontaria, Canada [population genetics, hybridization, clonal co-existence, enzyme variability]
Herzig, B,iologische Station Neusidlersee, A-7142, Illmitz, Austria. [Ecology, population dynamics and production]
Hudec, Hydrobiological Laborator, Dumbie~ska 16, C5, -04159 Kosice, Czechoslovakia. [Systematics, distribution and ecology]
J.. Jacobs, Zoological institute, University of Munich, D -8000 MUnchen 2, Germany. [Cyclbmorphosis, allometery]
V. Korinek, Department of Hydrobiuology, Charles University, Prague, Czechoslovakia. [Systematics, disbibution and ecology]
J. Gilbert, Department of Biological Sciences, Dartmouth College, Hannover, New Hampshire, USA. [Competition, predation, grazing and polymorphism] Korovchinsky, Institute of Animal Evolutionary Morphology and Ecplogy, USSR Academy of Sciences, Leninsky Prospect, 33 Moscow 117071, USSR. [Systematics, functional morphology, distribution]
Lampert, Max-Plank Institute fUr Limnologie, 2320 PIOn, Germany. [ecology, cyclomorphosis, predation, population genetics, feeding, nutrition]
Lieder, Institue of Indland Fisheries Research, 1162 Berlin, Germany. Systematics and distribution
Lynch, Department of Ecology, University of Illinois, Illinois, USA. [ecology, evolution, competition, biology]
Matsumura-Tundisi, Departmento de Ci~ncias Biologicas, Universidade Federal de Sao Carlos, Sao Carlos, Brazil. [Systematics, distribution and population ecology]
Paggi, Institute Nactional de Limnologia, 3016 Santo Tome, Argentina. [Systematics, distribution and ecology]
Pejler, Institute of Linmology, University of Uppsala, Box 557, Uppsala, Sweden. [Distribution, ecology and production]
Peters, Department of Biology, McGill University, 1205 Ave. Dr. Penfield, Monttea1, Quebac, Canada. [Feeding, metabolism, excretion, phosphorus regeneration by Zooplankton and culture]
Ringelbcrg, Department of Aquatic Ecology, Univesity of Amsterdam, Kruislaan 320, 1098 SM Amsterdam, The Netherlands. [Behaviour, circadiam rhythm, spatial orientation, vertical migration]
R.J. Shiel, Murray Darling Freshwater Research Station, Albury NSW, Australia. [Systematics, distribution, feeding and ecology] N.N. Smimov, Institute of Evolutionary Morphology and Ecology of Animals, USSR Academy of Sciences, Leninsky Prospect, 33 Moscow 117071, USSR. [Systematics, global distribution, functional morphology, ecology and biology]
R.G. Stross, Department of Biological Sciences, State University of New York, Albany, New York 12222, USA. [photoperiodism, phased growth, population coactions, diapause] Swar, Department of Agriculture, Fisheries Development Centre, Pokhara, Nepal. [Systematics and ecology] Rajapaksa, Department of Biology, University of Waterloo, Waterloo, Ontario, Canada. [Systematics and distribution]
S.T. Threlkeld, Biological Station, University o~ Oklahama, Kingston, UK 73 439. [Population ecology, dynamics, habitat selection, life history]
Timms, Sciences Department, Avondale College of Advance Education, Cooranbogh, NSW, Australia. [Systematics, distribution, associations and ecology]
Vijverberg, Limnological Institute, Tjherkemeer Laboratory, 8536 UD Oosterzee, The Netherlands. [Culture, feeding, ecology, population]
Zaffagnini, Institute di anatomia Comparata, Via LiBorsari 46, Universita di Ferrara, 44100 Ferram, Italy. [Reproduction, ethology and ultrastructure]
Selected References Amoros, C. 1984. Crustaces Cladoceres. Bull. de la Soc. Linneenne de Lyon, S3 (3 &4): 72¬ 143.
Biswas, S. 1971. Fauna ofRajasthan, India. Part II. (Crustacea: Cladocera). Rec. zo.ol. Surv. India, 63 : 95-141.
Brehm, V. 1936. Yale North India Expedition. Report of Cladocera. Article XVI. Mem. Conn. Acad. Arts Sci., 10 : 283-297.
Brehm, V. 1953. Indische Diaptomiden, Pseudodiaptomiden und Cladoceren. Ost. Zool. Zeit., 4: 241-345.
Fernando, C. H. 1980. The freshwater Zooplankton of Sri Lanka, with a• discussion on tropical freshwater Zooplankton composition. Int. Revue ges. Hydrobiol., 6S : 85-125. Fernando, C. H. &Kanduru, A. 1984. Some remarks on the latitudinal distribution of Cladocera in the Indian subcontinent. Hydrobioiogia, 113 : 69-76.
Goulden, C. E. 1968. Ths Systematics and evolution of Moinidae. Trans. Amer. "Phil. Soc. N.S., 58 (6) : 3-101.
Herbst, H. V. 1962. BlattfUsskrebe (Phyllopoden : Behte BlattfUsser und WasserflOhe). Stuttgart: 1-130.
Lilljeborg, W. 1900. Cladocera Sueciae. Nova Acta Reg. Soc. Sci. Uppsala, Sere III,. XIX : 1¬ 701. Michael, R. G. &Sharma, B. K. 1988. Fauna ofIndia and Adjacent Countries Cladocera. Publ. by Zool. Surv. India, Calcutta. 262 pp.
Sharm~ B. K. &Michael, R. G. 1987. Review of taxonomic studies on freshwater Cladocera from India with remarks on biogeography. Hydrobiologia, 14S : 29-53.
Sharma, B. K. & Sharma, Sumita, 1990. On the taxonomic status of some cladoceran taxa (Crustacea: Cladocera) from Central India. Rev. Hydrobiol. trop., 23 : 105-113.