Rotifera: India
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Rotifera
Introduction
The rotifers comprise a group of pseudocoelomate microscopic organisms usually ranging in size between 40 Jlm -250 Jlm while some large species (rarely extending upto 2.5 mm) can be percicved by the unaided eye as minute dots, sacs or rods. They have been invariably treated as a class of the Phylum Aschelminthes or even as a distinct phylum by some authors and they exhibit many structural features in common with Gastrolricha and Nematoda. Clemente (1980) atlributed their affinity to Platyhelminthes and postulated that these two groups probably had a common ancestor. According to Sladecck (1983), the rotifers represent a very old group of invertebrates and are presumed to be a product of the aerobic phase in the development of our planet though there is yet no palaentological evidence to support this view.
These fascinating creatures have long been called Rotifera or 'Rotatoria' or 'Wheel-animalcules' as their disc-like anterior end (corona) bears resemblance to a pair of revolving wheels owing to the synchronized beating of their coronal cilia. These are also characterised by a specialized pharynx called the mastax, with its cuticular lining differentiated into trophi which act as jaws. These micro-organisms shows remarkably intricate structure and exhibit endless profusion in their body fonns which are morphologically well adapted to their living habits and closely related to their habitats. The vast majority of rotifer encountered under natural conditions are females, males, however, are known relatively for a few species, they are diminutive, degenerate and seldom survive for more than a couple of days. The rotirers show world-wide distribution, possess striking 'ability to colonise diversified biotopes and indicate rapid tum-over rates. They reflect interesting strategies for reproduction, population dynamics, spatial and vertical distribution and survival while some of them are notable for the ecotypic and cyclomorphic v~tions and prey-avoidance mechanisms. .
Rotifers are mainly found in freshwater which is considered their original habitat. However, during the course of their evolution to the present multiplicity, they have invaded and become adapted to various other habitats. As a result, they are now encountered in a wide range of aquatic and semi-aquatic environs. They are more important in freshwater ecosystems because of their occurrence in practically all biotopes varying from a trickle on the rocks and small tree-holes to large rivers, from bogs to inland salt water lakes and from ephemeral polls to the limnetic, littoral or deepest regions of the largest lakes.
This view is supported by the fact.that about 95% of the mtifers are known from freshwater habitats while less than 5% of them are known to restrict in marine or brackish waters. Amongst the groups of the animal kingdom which established in freshwaters, only few succeeded in leaving the bottom to inhabit the pelagial region. Rotifers are prominent than almost any other such group to adapt to the open water as about 30% of the,rotifer genera live constantly or occasionally in the plankton. Besides aquatic ecosystems, the rotifers occur in decomposing vegetable debris (e.g. manure pits),. in mosses dampened onJy occasionally and in the interstices between the sand grains of lake and river beaches from the Arctic and Antarctic to the Tropics. The rotifers comprise an important component of soil micro-invertebrate communities (the Edaphon). Freshwater environments are predominated by the monogononts while only 20-30% of bdelloids inhabit the shores of these ecosystems. On the other hand, about 95% of the rotifers found in mosses and soil are bdelloids.
A majority of these organisms are free-living and solitary, sessile or colonial taxa belong only to a few families. A few species of rotifers are known to take to commensal or synoecious associations with freshwater cladocerans, snails, insect larvae, prawns and other lower crustaceans. Only few species are reported to be parasitic on some coloniaJ or filamentous algae (e.g. Volvox, Vaucheria) and aquatic worms (May, 1989).
Importance: There is yet no evidence that rotifer~ are injurious to any animal or plant that is of importance to human beings. They, however, comprise an integral link in the aquatic food-chain; the part played by them in the biological productivity is of considerable significance partly because of their rapid turn-over rates and metabolism and partly. because many species largely feed on detritus and bacteria and are consequently to a great extent independent of autotrophic production,. The rotifer invariably constitute a dominant component of freshwater Zooplankton and , hence, contribute significantly to their dynamics and production. They often serve as food for fry, fingerlings and adults of various commercially important and culturable species of fishes. It is in this context that during the last couple of decades considerable attention has been focussed on intensive culture of various species of freshwater and brackish water rotifers as supplementary food for aquaculture practices. These organisms are regarded as valuable bio-indicators to depict the trophic status of water quality of their environments within limnosaprobity (Sladecek, 1983; Berzins and Pejler, 1989) and, therefore, these organisms are being increasingly used in environmental toxicological studies and bioessay experiments. The soil rotifer~ play an important part in the food balance of these biotopes owing to their abundance and wide range of feeding habits. They aid countless other micro-organisms in promoting the proliferous structure of the soil by constructing their nests between gains, depositing their wastes ans fmally adding their own dead bodies. .
Nomenclature: Leeuwenhoek (1703) was the first to provide figures and descriptions of rotifers (particularly bdelloids) but considered them as protozoans. Linnaeus (1758) listed three species of these organisms under Zoophyta. Baker (1764) mentioned them as Wheel-Animals but did not auempt any classification. Muller (1773, 1786) and Pallas (1776) described many species but considered them Infusoria. euvier (1798) placed them in Kingdom Zoophytes, Class Infusories.
The term Rotifera, however, was first applied by Du Trochel (1812) who also regarded them as a biological unit set apart from Protozoa. Lamarck (1816) considered them as section of the order Polypes Cilies among 'animaux apatiques' corresponding to Zoophyta of Cuvier. Ehrenberg (1832) treated them as a class of Infusoria and proposed the term Rotatoria. Ehrenberg (1839) classified Rotifera among the worms. Metschnikoff (1864) established the distinction between them and Gastrotricha.
Hastschek (1878) recognised the trochophore larvae and Rotifers as having the same grade of structurc. Zelinka (1889) included both Rotifera and Gastrouicha under Aschelminthes. Remane (1929-33) believed them to be the larvae of unknown worms that remained in their larval stage. Various other considcrations on this group are detailed in the works of Edmondson (1959), KuLikova (1970) and Koste (1978).
Till recently, the terms ROLifera and Rotatoria have been frequently used for this group. Ricci (1983) questioned the nomenclatural validity of the use of these tcnns and after critically reviewing the literature recommended that the term 'Rotifera' by Cuvier (1798) should be regarded as the correct name while 'Rotatoria' by Ehrenberg (1832) was proposed as a synonym of the former.
Classification: As mentioned earlier, Rotifera are more commonly included as a Class of the Phylum AschelminLhes while Edmondson (1959) also considered them as a separate Phylum. Various earlier auempLS at classification of this group presented a number of anomalies. The first standard classification was proposed by Harring (1913) but the detailed classification of Remane (1929-33) laid the foundation for the systematic work of Voigt (1957) but .some changes were subsequently incorporated by Edmondson (1959), Sudzuki (1956), Dc Beauchamp (1965), Kutikova (1970) and Kostc (1978). Other diagnostic works were by Rodescu 1 (1960), Dommer (1965) and Ruuner-Kolisko (1974).
The general system of classification followed in this account is after Koste (1978) and for specific work on bdclloids the publication by Donner (1965) is taken into consideration. The division of class into subclasses and order derives from the slIucture of the female genitalia while families and lower subdivisions are differentiatoo on the structure of corona and the types of trophi.
Freshwater rotiCers belong to various families of Sub-class: Eurotatoria and marine fonns are represented by only one genus (Seison) of sub-class Seisona (Family Seisonidae). Bdelloids (Super-order Digonota) comprise an important component of moss-dwelling and soil rotiCers.
Historical Resume
The rotifers were first studied and described by Lecwenhoek (1703) following the invention of microscope. Since then, these interesting organisms have drawn world-wide attention of amateur naturalists as well as professional hydrobiologists because of their intricate structure, profusion of body forms, wider di~tribution and easy availability. However, studies on this group from India date back to later part of the 19th century. Various investigations related to taxonomy, zoogeography and ecology of rotifers from this country are detailed below under three periodic levels:¬
i) Pre-1900
This period incorporates the sole contribution of Anderson (1889) who initiated faunistic studies• on freshwater rotifers from India. His collections from various aquatic ecosystems in and around Calcutta (West Bengal) dealt with 47 species, including the descriptions of 10 species and two uncertain species.
ii) 1901-1947
The studies during this period commenced with a list of 32 species of rotiCers from the slopes of the Sikkim Himalayas, between altitudes of 610m -2440m (Murray, 1906). This list included 8 species each of the genera JJabrotrocha and Macrotrachela, 7 species of Philodina, 3 species of Rotaria and one species each of the genus Adineta, Proales, Squatinella, Colurella, Lecane• and Brachionus. The predominance of bdelloids in Murray's material was due to the fact that these collections were made from mosses. After a time-lag of nearly three decades, Edmondson and Hutchinson (1934) examined samples obtained by Yale North India Expedition from 52 localities in the Punjab and Northwest Frontier Province (all parts now in Pakistan), 15 localities in the Kashmir basin (altitude between 1585m -2620m)', 24 localities in the then Indian Tibet and. the extreme western part of the Tibet Propcr (altitude between 3200m -5334m) and 9 localities from the Nilgiri Hills in Southern India (altitude between 2133m -2316m). These authors enumerated 99 species (excluding a few doubtful forms) from the mentioned samples that were taken mostly from alkaline waters at moderate or low temperatures.
This paper included taxonomic and Zoogeographical notes, morphological variations in Cephalodella catellina, Filinia longisela. Keratella valga and K. quadrata and comments on the rotatorian fauna of high altitudes. Edmonson and Hutchinson also gave a list of 37 valid spccies amongst those documented earlier by Anderson (1889).
Dr. R. B. S. Sewell, Late Director, Zoological Survey of India initiated work on rotifers in this institute. Sewell (1934) in his comprehensive study of the fauna of Salt Lake, Calcutta referred to five species from brackishwaters i.e., Brachionus pala (= B. calyci[lorus), B. bakeri (= B. quadridentatus), B. rubens, B. urceolaris and Asplancha brightwelli and two varieties of B. bakeri. Of these, A. brighlwelli was also reported to be common in freshwaters in and around Calcutta. Subsequently, Sewell (1935) gave a classical account of fauna of the tank in the Indian Museum compound and its seasonal changes based on the collections made during 1929-31. This paper dealt with 11 specics of rotifers and their seasonal occurrence.
Karlsruhe worked on collections sent by Prof. (Dr.) Chappius, from some lakes in the then Madras Presidency and published three papers. First one dealt with the description of Lecane sola from Almati lake and Monostyla conspic14a M. bulla, f. diabolica n. f. from Sholavarum lake. In addition, two new species of Trichocerca from Almati lake were documented in second one (1937) and third one (1937) dealt with a new variety and new form of Brachionus angularis from
Sholavarum and Almati lake. Ahlstrom's (1940) paper on the rotatorian genera Brachionus and Platyias referred to the material examined by Hauer (1937). Further, Ahlstrom (1943) in his revision of the genus Keratella dealt with a new variety of Keratella quadrata from Ootacamund lake, MadrasLittle was known about the ecology of rotifers till the end of this period. Edmondson and Hutchinson (1934) referred to pH and water temperat~e while Sewell (1934) dealt with the salinity of the examined samples. Sewell (1935) made an attempt to explain seasonal chang~s of the fauna in relation to certain ecological parameters observed earlier by Pruthi (1933). This information was supplemented by Ganapati (1943) in his comparative swdy of plankton abundance in a garden pond at Madras.
Various earlier works till 1947, even though fewer in number, made significant contributions to systematics and distribution of rotifers in India, gave information about fauna of Salt Lake and initiated ecological studies on this group.
iii) 1948-1990
The period between 1948-1960 included a few taxonomic publications based on the collections by Dr. V. Brehm, Limnologial Institute, Lunz am See, Austria and those examined by J. Donner (an Austrian monk). Donner (1949) described Horaella brehmi"nov. gen. et. nov. sp. from a tank in Banikpore, Bihar (collection v. Brehm, dated 13.9.1902) and listed another five species of rotifers, three species of cladoceran and two sp~ies of copepods from this sample. Further, Donner (1953) referred to Brehm's material from a filtration bed in Madras while describing Trichocerca (Diurella) ruttneri from Java and Sumatra, India and Neusiedlersee (Austria). Brehm (1950) in his article on the freshwater of India (part II) dealt with three species of rotifers, including Keratella cochlearis from Palta water works in West Bengal. Subsequently, Brehm (1951) described Br.achinus donner; an interesting brachionid, fr,om Almati reservoir, Madras~
During 1951-60, contributions to rotifers ecology comprised parts of few studies on plankton ecology. Ganapati and Chacko (1951) studied plankton production and limnology of four fish ponds at the Chetpat fish farm, Madras while Chacko and Krishnamurty (1954) dealt with plankton on three freshwater ponds in Madras city. Dutta el al., (1954) made observations on seasonal and periodic fluctuation in the plankton of Hooghly Estuary ~tween a stretch of 68 miles from Palta to Diamond Harbour. Roy (1955) analysed plankton ecology of Hooghly river at Palta. Alikunhi et al., (1955) examined quantitative variations of rotifers in a few nursery ponds at Cuttack (Orissa), though annual population was not attempted. The studies of Das and Srivastava (1955, 1956, 1956b) dealt with quantitative fluctuations of plankton and their ecology in a fi~h-pond and some tanks at Lucknow(Uttar Pradesh).
From 1961 onwards, there was considerable proliferation of researches related to systematics and ecology of these organisms from scattered localities and involving participation of workers from various institutions and universities. Different developments are treated separately in three following decades in view of accwnulation of vast and diversified literature. The decade between 1961-1970 included taxonomic studies from Tamil Nadu. Pash (1961) reported six species of lecanids. from freshwater tanks and Coovum river in Madras. Hutchinson (1964) resurrected Filinia pejleri based on the figure given earlier by Edmondson and Hutchinson (1934) from Ootacamund lake (Madras).
In addition, Michael (1966) described a colonial rotiCer, Conochilus madurai from Madurai while Wycliffe and Michael (1968) dealt with Pseudombale acutipoda an epizoic bdelloid from gill¬chambers of Caridina sp. From the state of Maharashtra in western India, Arora (1962, 1963, 1963, 1965, 1966, 1966, 1966) presented a faunistic account of rotiCers from polluted and clean water bodies in Nagpur city, gave ecological notes for different studied taxa and made observations on cyclomorphosis in Brachionus calyciflorus, Keratella tropica and Platyias patwus. Dvorakova (1963) examined rotifers from the Yamuna river, and described a new species of the genus Lecane.
Nayar (1964, 1965) studied morphometric variations and cyclomorphosis in Brachionus calyciflorus from Rajasthan and documented (Nayar, 1868) 36 species (including on new species) of rotifers from this state. Nayar (1965b) gave taxonomic notes on Indian species of genus Keratella. Further, Nayar and Nair (1969) reported 15 taxa of southlbrachionid rotifers from Kerala in India. Wulfert (1966) examined collections, from Ajwa river and Nimeta Water works, Baroda sent to him by Drs. Ganapati and Jayangounder and dealt with 81 species (including 9 new taxa and one new combination).
George (1966) made observations on cyclomorphosis in Keratella tropica from Roshnara tank, Delhi. Naidu (1967) initiated systematic investigations from Andhra Pradesh and dealt with 12 species from temporary rainwater puddles at Vijayawada and two old wells at Cuddapah and Chittoor. Subsequent studies of Vasisht and Gupta (1961) and Vasisht and Battish (1969, 1970) contributed 26 species from Chandigarh (Union territory) in North India Vasisht and Dawaf (1968) gave f1l'8t description of male of Cupelopagis vorax from• this city while an elaborate account of anatomy and histology of Lacinulariaflosculosa was presented by Vasisht and Dawar (1970)
Ecological studies indicated co~siderable impetus during 1961-1910. Arora (1961) made observations on responses of rotifers to variations in some ecological factors (temperature, pH and dissolved oxygen). Arora (1961, 1966) made fust attempt to designate trophic indicators amongst rotifers based on his observations in different water bodies in Nagpur city. George (1961) examined abundance of rotifers in five fish tanks at Delhi and later (George, 1966) gave a detailed account of comparative plankton ecology in these ecosystems. Moitra and Bhowmik (1968) studied seasonal cycles of rotifers in a freshwater fish pond at Kalyani (West Bengal). In addition, observations on the rotifer populations of two ponds at Pilani, Rajasthan were made by Nayar (1970).
Some more investig~tions on rotifers as part of general plankton studies were from ~ataka (Gounder and Patil, 1961), West Bengal (Shetty et al., 1966; Moitra and Bhattacharya, 1966; Michael, 1968, 1969), Uttar Pradesh (Dcvassy; 1965; Roy el at., 1966; Pahwa and Mehrotra, 1966), Bihar (pahwa and Mehrotra, 1966), Tamil Nadu (Sreenivasan, 1968), Chandigarh (Vasisht, 1968; .Vasisht and Dhir, 1970) and'-Kashmir (Das et al., 1969; Das, 1970).
The number of systematic studies nearly doubled between 1971-980. Vasisht and Battish (1971) contributed four papers dealing with rotifer faupa of North India based on collections from Chandigarb (Union territory) and Patiala (panjab). Nair and Nayar (1971) reported 18 specIes from freshwaters in and around Irinjalakuda (Kerala).
Rajendran (1971) described Conochilus arboreus n.sp. from Madurai while Michael (1913) gave a preliminary account ofrotifers from Tamil Nadu. Nasar (1973) and Laal and Nasar (1971) studied rotifer samples from Bihar. Ten important taxonomic contributions from Andhra Pradesh were made by Ohanapathi which were supplemented by two papers by Chandra Mohan and Rao (1976a, 1977) and Rao and Chandra Mohan (1976a, 1976b 1977). Some studies on the"fauna of Jammu and Kashmir were undertaken by Das and Akhtar (1976), Das (1977), Qadri and Yousuf (1977) and Jyoti and Sehgal (1980). Bhardwaj el al.• (1978) studied a few colonial rotifers from Haryana.
Rotifer systematics in Zoological Survey of India remained unattended after initial publications of Sewell. This work was taken up agai') by this author between 1975-1978 as a research fellow in this institute and resulted in important contributions to the rotifer fauna of West Bengal (Tiwari and Sharma, 1971; Sharma, 1978-1980) 1978c, Himachal Pradesh, HaI'Y.ana and Panjab (Sharma, 1976) and Orissa (Sharffia, 1917, 1980). Later on, Sharma (1980) dealt with 38 species of Eurotatoria feom Assam State in North-Eastern India while Sharma and Michael (1980) presented a synopsis of taxonomic studies on Indian Rotatoria.
The period between 1911-1980 reflected almost same magnitude of ecological information (in tenns of total publications) as in the preceding decade. The studies of Rao and Chandra Mohan (1971),-Oas (1918) and Vasisht and Sra (1979) dealt with pollution indicators. In addition, Vasisht and Sharma (1976, 1977) and Jyoti and Sehgal (1979) made observations on their ecology from Haryana and Jammu respectively. Tiwari and Sharma (1971) commented on changes in species composition of the rotifees in Indian Museum tank, Calcutta •in light of the earlier observations by Sewell (1935). Various other contributions included rotifers in general plankton ecology and these were from Orissa (Saba et al., 1971), West Bengal(Moitm and Mukherjee, 1972; Jana, 1973, 1976, 1979; Sircar and Sen, 1975; Jana et al., 1980; Mondal, 1980), Andhra Pradesh(Seenaya, 1973; Sugunan, 1980), J(ashmir(Das. 1971; Kaul et al., 1978; Zutshi and vass, 1978; Khan and Zutshi, 1980; Zutshi et al., 1980), Bihar (Nasar and Dutta-Munshi, 1974; Nasar, 1977), Madhya Pradesh (Mathew, 1977), Karnataka (Prasadam, 1977), Haryana (Vasisht and Shanna, 1975), Uttar Pradesh (Das and Pande, 1978) and Panjab (Vasisht and Jindal, 1980). The only report of production of rotifers from India was by Nandi et al., (1977) who conducted experiments on mass culture of Brachionus mulleri (=B. plicatil{s) in glass aquaria using common inorganic and organic manures.
There was slight decline in taxonomic studies during the last decade of this review i.e., between 1981-1990. The contributions began with the paper by the author (Sharma, 1981) dealing with 20 species of family Brachionidae from Panjab While later work (Shanna and Sharma, 1984) added 35 species to the fauna of this state. Sharma (1983) reviewed status of Indian species of genus Brachionus and subsequently (Sharma, 1987a) commented on the brachionid rotifers from this country and their distribution. Various other studies by the author and co-worker dealt with rotifers from North-Eastern India and these related to LepadeUa species (Sharma and Sharma, 1987a), Family Notommatidae (Sharma, 1987b), Family Lecanida (Sharma, 1987b), Testudinella species (Sharma, 1990a) and distribution of brachionids this region (Sharma, 1990). In addition, Sharma (1987c) documented 69 species from Orissa State while Sharma and Sharma (1988) reported 35 species of monogononts from Haryana.
A comprehensive account of systematic, distribution and ecology of freshwater rotirer from West Bengal was given by Sharma (1990b). Further, Sharma et al., (1990) documented 55 species of rotifers from Bihar.
Other studies during this period included those from Gwalior (Madhya Pmdcsh) and dealt with faunistics (Saksena and Sharma, 1981a, 1982; Shanna and Saksena, 1981; Saksena and Kulkarni, 1986a), cyclomorphic variations in Brachionus calycij10rus (Saksena and Sharma, 1981), form variations in B..quadridentatus (Saksena and Sharma, 1986) and feeding of Asplanchma brightwelli (Saksena and Sharma, 1984). Saksena (1984) also gave an account of form variations in Indian ~oricate rotifers. A few publications dealing with morphology, colony formation and life-history of colonial rotifers were those by Bhardwaj and Duttagup~1 (1984) and Bhardwaj (1985). Systematic studies on the fauna of Kamataka were attempted by Patil and Gouder (1982, 1989).
The rotifer from lentic and lotic water bodies in and around Patna (Bihar) were examined by Ahmed and Singh (1988) while Misra (1989) reported six species from lentic waters at Bhind (Madhya Pradesh). Sarma (1988) gave an account of27 species (including 25 new records from India) from Kashmir, Delhi and West Bengal.
More attention was focussed on synecology of rotifers during 1981-1990 as reflected by investigations undertaken by Mukhopadhyay et al., (1981); Rao et ale (1981); Qadri and Yousuf (1981, 1982); Yousuf and Qadri (1981, 1986); Balkhi et al., (1984, 1987); Laal (1984); Sandhu et al., (1984); Sharma and Pant (1985); Yousuf et al., (1986); Deb et al., (1987), Haque et al., and Sharma (1990). Additional information was also provided in limnological studies by Patil and Gounder (1985) from Karnataka; Bhattacharya and Saha (1986, 1989) from Tripura, and Khan et. al., (1986) from Uttar Pradesh and Vass el al., (1989) from Kashmir, Some contributions by Sampalh et al' (1981), Sharma (1983, 1986), Outta and Bandhyopadhyay (1985) and Saksena J (1987) dealt with trophic indicator species of rotifers.
So far only publication from this country dealt with karyological studies in this group; Rishi et al., (1983) made these observations in AsplancMa brightwelli.
Recently, studies were undertaken on autoecology, production of mictic and amictic females, production and population dynamics in Brachnionus patulus. The results of these investigations are presented in the publications by Rao and Sarma (1985), Sarma and Rao (1985, 1990, 1990) and Sarma (1989).
Studies from Different Environs
Systematic studies on the rotifers from India commenced in the later part of 19th century but initial progress till 1960's was relatively slow and resulted in only 14 papers (mostly by foreign workers). However, important pre-independence works of Anderson (1889), Murray (1906) and Edmondson and Hutchinson (1934) altogether reported about 150 species; this comprised a significant fraction of total species so far known from this country. A considerable proliferation of faunistic researches were subsequently registered between 1961-1990. As\a result, the present literature on Indian Rotifera is scattered over 105 papers referring to samples from distant localities from the northern latitudes to those from tropical environs of the southern plateau. .
These investigations primarily relate to systematics of freshwater rotifers from the mainland; only a fewer of these works included biogeographical comments on this group. In addition, about 10 publications from this country deal with morphometric variations, fonn variations and cyclomorphosis in some planktonic and semiplanktonic members of the family Brachionidae. Sharma and Michael (1980) presented a synopsis of taxonomic studies on Indian Rotatoria, listed earlier references and remarked on the number of species and genera documented from different States and Union Territories.
The current status of occurrence of rotifer species (fig.) is marginally altered in some states following additional studies in the last decade.
Although various taxonomic investigations were undertaken from scattered localities from different geographical areas, our present knowledge of the freshwater-rotifer fauna of India is still incomplete. This could be attributed to lack of extensive State-Wise or regional faunistic studies based on collections from diversified inland aquatic ecosystems as also highlighted by Sharma and Michael (1980). Further, a good fraction of previous works were focussed on planktonic rotifers only from tropical alkaline water bodies in this country and, therefore, .resulted in localized species inventories and in some cases merely extended local distributional limits of species already reported from India. Moreover, many studies dealt exclusively with new taxa or new records. Earlier literature, ifviewed in terms of number of publications from different states, presents a misleading picture of overall taxonomic contributions.
Till now, eurotatorian fauna of West Bengal is adequately explored and that of Orissa, Punjab, Andhra Pradesh and Jammu and Kashmir is moderately known. Extensive Investigations from different states of this country are still required and some studies are being undertaken by this author and co-workers from various parts of North¬Eastern India and from the states of Orissa and Bihar in Eastern India. Even additional collections from hitherto studied regions are likely to add more rare and interesting taxa this fact is evident from earlier record of 110 species from West Bengal (refer Sharma and Michael, 1980), subsequenlly this figure is presently (Sharma, 1990) raised to 148 species and represents highest diversity so far documented from any particular state of this country. Besides lacunae related to mainland, distant insular freshwater ecosystems of Andaman and Nicobar islands and Lakshnadweep Archipelago remain unexplored; some collections from the fonner group of islands are being examined by the author~
Amongst various freshwater ecosystems, water bodies infested with different assemblages of aquatic macophytcs and rice-fields deserve special mention to examine species composition of their rotifer communities. Michael (1968) listed 30 species of these organisms from a fish-pond of the former category from West Bengal while Sharma (1990) recorded overall diversity of 72 species in these habitats from the mentioned state. In addition, the author (unpublished data) examined 53 species from five such ponds from Bihar. The later biogopes (rice-field ecosystems) are still more interesting as indicated by the records of 30-32 spccies/individual sample from Meghalaya (Shanna and Sharma, 1987) and upto 54 species/single sample from Assam State in North-Eastern region (Sharma, 1987).
A critical analysis of Indian freshwater Rotifera indicates that various planktonic and semi¬planktonic taxa are fairly well documented from this country while periphytic, benthic, colonial,
sessile and bdelloid rotirers are 'still not adequately studied. Morhphometric variations are so far examined in a few brachionid species and could be extended to various other taxa ~ecially based on populations studies from varied geographical areas (under different ecological conditions) and with particular reference to the phenomenon of dwarfing in tropical rotifers (Green, 1977). Some species of the brachionids are known to exhibit ecomorphic variations and these require further analysis from 'various freshwater ecosystems. Taxonomic studies supplemented with information on basic parameters of water quality and aquatic macrophytic associations (if any) are desirable for any fruitful comparison of rotifer communities from different parts of this country. While genetic and biochemical methods remain beyond resources and expertise of most rotifer systematists, detailed SEM studies will serve as valuable adjunct to classical taxonomy and to resolve nomenclatural discrepancies (Koste and Shiel, 1989).
So far only one paper (Murray, 1906) gave an account of mossdwelling rotifers and reflected predominance of bdelloids (27 species) in these biotopes. Additional studies from these interesting habitats, particularly relating to types of moss, will essentially augment otherwise poorly documented digonont rotifer fauna of this country. This generalisation also holds true for soil rotifers (because of abundance of bedelloids) which remain totally unexplored from India. In addition, investigations on psammo-littoral and marine rotifer communities are yet to be initiated. Brackishwater rotifers are practically unknown systematically. Sewell (1934) in his account of fauna of brackish environs of Salt Lakes, Calcutta dealt with species which occurred primarily in fresh waters and indicate euryhaline nature. Some other species of the former category i.e~, Brachionus plicatilis and Tripleucha/anis plicata are also documented from inland waters in this country. However, further investigations need to be undertaken in brackishwater ecosystems to record their characteristic elements.
Limnological studies in India were initiated by Sewell (1935) and since then there has been considerable activity of researches in this field (Michael, 1980; Gulati and Wurtz-Schulz, 1980). Rotifers invariably figure in Indian publications relating to general plankton ecology and were reponed to comprise a dominant or sub-dominant component of freshwater Zooplankto~ic communities. It is not possible to cover all such references within this short review primarily relating to this group. However, about 80 papers from this country provide some worthwhile information on various aspects of seasonal composition, abundance' and ecology of these organisms.
Although this literature dealt with various freshwater ecosystems scattered over futeen/Union territories, a large number of these contributions relate to rotifer communities from tropical fish-ponds or tanks. So far, only about 18 publications dealt exclusively with synecology or rotifer populations. A majority of Indian contributions were made from the states of West Bengal, Jammu and, Kashmir and Uttar Pradesh. A good fraction of these works (Das et al., 1969; Das, 1970; Khan and Zuthis, 1980; Zutshi et 01., 1980; Qadri and Yousuf, 1981, 1982; Yousuf and Qadri, 1981, 1986; Balkhi et al., 1984, 1987; Yousuf et al .• 1986; Das, '1989; Vass et 'ale 1989) referring to their species composition and ecology from Kashmir lakes. Jyoti and Sehgal (1979) conducted investigations in a sub-tropical lake near Jammu while Kumaun lakes were studied by Das and Pande (1978) and Sharma and Pant (1985).
However, there is so far no published report from sub-tropical or temperate lacustrine ecosystems from North-Eastern India. Only fewer investigators (Devassy, 1965; Mathew: 1977; Sugunan, 1980; Bhattacharya and Saha, 1986, 1990) dealt with rotifer ecology from other lakes and reservoirs in this country. Still fewer studies relate to their ecology from riverine ecosystems (Roy, 1955; Ray et al.• 1966; Pahwa and Mehrotra, 1966) while observations in estuaries are those by Dutta et al., (1954) and Shetty et al., (1961).
Rotifers serve as valuable indicators of water quality and rust attempt to designate such species from India was made by Arora (1961. 1966). Some additional information was provided by Rao and Chandra Mohan (1977), Vasisht and Sra (1979), Sampath et al., (1981), Sharma (1983, 1986), Dulta and Bandhopadhyay (1985) and Sakscna (1987). However, a careful examination of regional ecological conditions is necessary before indicators mentioned by these authors are applied to other parts of this country. Slacecek (1983) proposed Q Brr q~otient, and analogen'to various phytoplankton quotients, and could be tried by Indian rotiferologists to establish trophic conditions of individual water bodies or even individual samples.
Considerable attention has been focussed world-wide on intensive culture of rotifers as fish¬food. First attempt in this country was made by Nandy et al., (1977) and dealt with mas rearing of Brachionus plicatilis using common inorganic and organic manures. In addition, recent studies of Rao and Sarma (1985), Sarma and Rao (1981, 1990a, 1990) and Sarma (1989) concerned various aspects of autoecology, population dynamics and production of Braehionus patulus.
The above comments reflected limited infonnation on synecology of rotifer communities in freshwater and esturine environments in general and autecology of individual species in particular. Further studies need to be focussed on species compositions, spatial and vertical distribution, biomass production, popUlation dynamics, effect of predation, eutrophication and acidification on rotifer biocoenosis, trophic indicators and intensive culture of selected freshwater and brackishwater species from this country.
Estimation of Taxa
Out of two subclasses of Rotifera, only subclass Eurotatoria is represented in India and -it is comprised of taxa that generally occur in a wide range of aquatic and semi-aquatic ecosystems while studies on marine forms of subclass Seisona are not yet attempted. Amongst 29 eurotatorian families recognised by Koste (1978),24 families are reported from this country and these include 310 species (345 taxa) belonging to 60 genera. Earlier synopsis by Sharma and Michael (1980), however, dealt with 241 species spread over 21 families and 48 genera.
The presently known species comprise only about 12.4 % of the World's rotifer fauna. Our knowledge of the fauna of this country is certainly incomplete as reflected by lacunae discussed earlier in this paper and any accurate assessment of the fauna is a difficult aspect but a conservative estimate of over 500 species cannot be ruled out. The number of species documented from this country present a notable contrast to the report of 620 species from Australia (~hiel and Koste, 1987) and over 1400 species from Europe (Dum not, 1983). Sudzuki (1989) complied a list of 575 species from the Oriental region and commented on relative richness of the rotifers in the Indian fauna; this conclusion may be misleading unless analysed in view of wider ecological conditions in this country, magnitude of taxonomic publications (about 64 % of examined papers by Sudzuki were from India) and unbalanced information form other countries of this region.
According to Sudzuki (loe. etc.), strangely enough, about 37% of the Oriental rotifers did not appear in India, particular among them was the absence of several tropical species and some cold~water species in its northern territories although their common associates occurred there.
The rotifer fauna of India exhibits greater specific and generic diversity than other South-East Asian faunas (Table 2) and also concerning members of the dominant families. Further, it shows about 60% similarity (vide Sorenson Index) with the rotifers examined from Malaysia and Singapore (Fernando and Zankai, 1981) and lower similarity (about 42%) with the Sri Lankan fauna.
Green(1972), Pejler (1977) and Fcrnando (1980) indicated common occurrence of Braehionus species to be a notable feature of tropical rotirer faunas while predominance of the lacenids (Family Lecanidae) from tropical Australasia was noticed by Dussart et al., (1984). The above generalisations also hold true for the rotirer fauna of India and, therefore, impart it a broadly tropical character. This conclusion is further supported by restricted occurrcnce of temperate species particularly those of NOlholca and Synehaela to the localities in the northern territories of the Kashmir valley.
Cosmopolitan taxa comprise an important fraction of Indian rotifers while cosmotropical,
310 60 tropical and subtropical components are fairly well reported. Endemic elements are represented by 26 species (32 taxa) and comprise abut 9.4 % of the fauna of this country. of these, 14 species belong to Lecane and Lepadella and hence confrrm to the remarks of Dumont (1983) regarding the occurrence of usual endemics of these genera in the fauna of South-East Asia. Overall paucity of Indian endemics in general and that of the family Brachionidae in particular was believed to be secondary and resulted due to loss of characteristic faunal clements afler this subcontinent his Asia (Dumont, loc cit.) and invasion of the Oriental faunal elements to the Near East especially during the Pleistocene. India Srilanka Malaysia &Phillipines Thailand Singapore
Out of the monogonont taxa from the Oriental region, about 51 % are detected from India (Sudzuki , 1989). This review also indicated that they comprise an important component of the fauna of this country and are represented by 281 species (22 families and 55 genera). This super¬order includes two orders i.e., Ploimida and Gnesiotrocha. The former incorporates 239 species (41 genera) while the later is comprised of 41 species (14 genera). The members of Lecanidae, Brachionidae, No tommatidae, Colurellidae and Trichocercidae (in the stated order) from major fraction of the ploimid fauna. The lecanids relate to Lecane-compex including three subgenera (Lecane s. str., Ilemimonostyia and Monostyla). Various endemic•taxa of the family Lecanidae are Lecane (Lecane) lateralis, L.(L.) luna dorsicalis and L. (L.) vasishti from West Bengal; Lecane(Lecane)pawlowski, L. (Monostyla) schraederi and L. (L.) neali from Gujarat; L. (L.)yamunensis from the river Yamuna; L. (L.) sola from Tamil Nadu; L. (L.) donnerianus, L.(L.) bidentata and L. (L.) esWari from Andhra Pradesh and L. (L.) jaintiensis from Meghalaya. The geographical limit of L. pawlowski was extended to West Bengal (Sharma, 1978) while L. lateralis was also examined from Orissa(Sharma, 1987). In addition, L. (L.) Curvilinealis, L. (L.) tesse/ala and L. curvicornis var. padaespares are considered to be apparently identical with L.(L.) curvicornis but type-specimens are not available for comparison.
Endemic taxa of the family Colurellidae include LepadeUa kostei from Gujarat; L. triprojectus. L.ovalis /arga n. comb from West Bengal; L.nartiangensis and L. patella elongata n. comb. from Meghalaya. The mentioned two subspecies were originally described as forms. Family Brachionidae includes Brachionus durgae described by Dhanapathi (1974) from Andhra Pradesh but its status needs to be ascertained(refer: Shanna, 1983). Platyias quadricornis andhraensis is another endemic brachionid documented from this state.
The endemic species of I:he euchlanis (Family Euchlanidae) are Euchlanis brrahmae and Pseudoeuchlanis longipedis from Andhra Pradesh; the later represents a monotypic genus described from this country. Other endemic elements from India include Proales indirae (Family Proalidae) from Gujarat, Ascomorpha saltans indica (Family Gastropodidae) also from the earlier state, Trichocerca tropis from Tamil Nadu and Asp/anchnopus bimavaerensis from Andhra Pradesh.
Order GnesioU'ocha includes suborders Flosculariacea and Collothecacea which are represented by six and two families respectively. Endemic elements of this order are Conochilus arboreus (Family Conochilidae) from Tamil Nadu and C. dossuarius asetosus from Maharashtra, Ptygura stephanion (Family Floscularidae) from West Bengal and another species of this family (Sinantherina triglandularis) from Maharashtra. AnimIJI Resources ofIndia
Fig.l. Map of India indicating number of reported sp ecies Map of India Indicating Dumber of reported species So far about 365 species (21 genera) of digonont rotifers (order Bdelloidea) and belonging to four families are known ~mthe world. Of these, 29 species spread over two Ifamilies and five genera are only documented from India. Endemic elements of bdelloids from this country include monotypic Ps~udoembata described from Tamil Nadu and Rotaria ovata from West Bengal.
Classified Treatment
Sub-Class Eurotatoria
All the rotifer taxa recorded from Indian and this sub continent belong to this subclass which includes freshwater and brackish water forms and is represented by both of its superorder i.e., Monogononta and Digononta.
Super-order Monogononta
Most studies on systematics, distribution and ecology from the Oriental region, nearly 51 % are detected from India,about 40% from Indonesia and Malaysia, approximately 35% from Singapore, 25% from Sri Lanka and about 18% and 16% from Taiwan and Thailand respectively. However,these comprise about 91 % of total 310 species presently docu~ented from this country. A number of important monographs (Voigt, 1957;Rodescu, 1960; Kutikova,1970; Koste,1978) deal with this superorder from different parts of the World while simple identification keys are provided by Edmondson (1959), Ruttner-Kolisko (1974) and Pontin (1978) but a comprehensive treatment from the Oriental region or any of its constitutent countries is yet to be attempted. Both orders of monogonont rotifers (ploimida and Gnesiotrocha) are represented from India. presently
Order Ploimida
This order includes a total of 17 families; of these, representatives of 14 families are reported from this country. However, members of some families have drawn considerable attention in earlier Indian studies.
Family Lecanidae
It is evidently one of the most important families in the rotifer fauna of India is represented by 70% species of the Lecane-complex which includes three subgenera i.e., Leeane s. str., Monostyla and Hemimonoslyla. The publications of Edmondson and Hutchinson (1934), Wulfert (1966), Dhanapathi (1975, 1976) Vasisht and Battish (1971) and Sharma (1978, 1979, 1987) provide valuable information about systematics of the lecanids from this country while knowledge of their ecology is relatively very poor. In view of various discrepancies reflected in our literature, this family needs revision to ascertain correct status of the documented taxa. 11 species (13 taxa) comprise endemic elements in the Indian fauna. Lecane nodosa, L.blachei, L.sinuata and L. thienemanni are apparently confined to Asia while the range of L. bulla diabolica is extended to Central Asia. Various other biogeographically important lecanids from India include Lecanae acronyncha, L. bi/astigata, L.eurvieornis miaminensis, L. hastata, L.lauterborni, L.doryssa, L.haliclysta, L.eiongala. "L.ligona, L.slokesii, L.pusilla, L.syngenes and L.elachis. In addition, L.pertie'a, L.inermis, L.bifurea. L.obtusa, Llurcata, L.perplexa and L.scutata are of local distributional significance. L. nartiangensis, L.dactyliseta. L.doryssa, L.perliea, L.inermis. Ljainliaensis, L.signifera signijera, L.,ligona. L.stokesii and L.seutata are regarded acidophilic elements. Lecane aculeata, L.ludwigi, L.sympoda, L.inopinala, L.quadridentata and L.stenroosi could be termed as wann-stenothermal species.
Family Brachionidae
The members of this family are most extensively studied faunistically and ecologically from India Out of seven genera of this family, four genera are reported from this country. Sharma (1983) gave an account of Indian species of Brachionus and later (Shanna, 1987) commented on
Indian Brachionidae and their distribution. More spr.cies of the genus Brachionus are reported to occur in alkaline water bodies in tropical parts of this country while slightly acidic biotopes particularly in North-Eastern region reflect lesser diversity. Intraspecific variations are documented in Brachionus calysijlorus. B. caudatus and B. quadridentatus while B. falcatus and B. forticula are observed to indicate ecotypic variations. In addition, morphometric variations from this country are studied in Brachionus angularis and observations on cyclomorphosis are made in B.calyciflorus and B. patulus together with the other member of this family i.e., Keratella tropica. B. angularis. B. caudatus, B.calyciflorus and B.rubens are considered as eutrophic indicators in Indian waters while B falcatus and B forficula are known to occur in meso trophic and eutrophic habitats. Brachionus bidentata crassispineus, B.bidentata testudinarious, B.bidentata jirovci, B.donneri, B.patulus mactracanthus. B.pterodinoides and B.sessilis are biogeographically important elements while B. dimidiatus, B.leydigi, B.bennini and B.mirabilis are of local distributional interest. Species of this genus invariably figure in ecological studies from this county and are reported to fonn significant component of planktonic rotifers. Culture of B .plicatilis was attempted in this county by Nandy et al., (1977)and various aspects of autecology of B.patulus were studied at Delhi University by Rao and Sarma. Keratella exhibits lesser diversity than the preceding genus.
Amongst various species reported from this country, K.ticinensis and K. javana are biogeographically interesting; K.lenzi. K.valga and K.procurva show restricted occurrence, K.lropica is widely distributed while K.cochlearis is an important planktonic rotifer in water bodies in North-Eastern India. Genus Anuraeopsis includes only tow species i.e., warm-stenothermal A.coelata and cosmopolitian A.fissa; the later occurs in eutrophic habitats. Amongst species of Platyias, P.leloupi was earlier considered to be aD interesting Ethiopian element but it is now reported (Sharma, 1987) to exhibit pantropical distribution. Notholca included two species which are confined to the northern territories in Kashmit while N.labis is recently reported from the river Yamuna (Sarma, 1988) near Delhi. Kellicottia longispina, a cold¬water species, documented ~rom Sri Lanka is notale for its absence though it is likely to occur in the collections from northern latitudes.
Family Epiphanidae
It has apparently drawn less attention and includes only seven species (four genera); important contributions about their occurrence in this country are by Edmondson and Hutchinson (1934), Dhanapathi (1974) and Sarma (1988). Of the documented species, Epiphanes clavatula and Liliferotrocha subtilis are warm-stenothermal elements.
Family Euchlanidae
This family includes thirteen Indian species belonging to Euchlanis, Dipleuchlanis, Pseudoeuchlanis. Tripleuchlanis and 8cauchampiella and important taxonomic studies on the euchlanids are made by Edmondson and Hutchinson (1934), Dhanapathi (1976) and Sharma (1979d). Amongst Euchlanis species, the boreal E.alala is reported only by Edmondson and Hutchinson (loe cit.) while E.dilalala is widely rcported in plankton coilections from this county. E.triquetra, E.menela and Dipleuchlanis propalula are regarded as acidic water species. Brackishwater Tripleuchlanis plicala is examined from freshwater bodies in Andhra Pradesh (Dhanapailii, 1975) and West Bcngal (Shanna,1979). The monotypic Pseudoeuchlanis is described by Dhanapathi (1975) from Andhra Pradesh.
Family Mytilinidae
Amongst seven species (two genera) of this family known from India Lophocharias oxyslernon, L.salpina and Mytilina mucronala arc examined only by Edmondson and Hutchinson (1934) and L.naias is reported by Wulfert (1966). Mytilina ventralis is mentioned to occur frequently in planktonic and periphytic samples in this country. M. ventralis longidactyla, M. ventralis brevispina and M.acanlhophora are biogeographicaUy important taxa. The cosmopolitan M.bisulcata was reported earlier from peat-bogs (toste, 1978) and has been noticed from a domestic well in West Bengal (Sharma, unpublished); its presence in the potable water is of special ecological-interesL
Family Trichotridae
It includes three species of M acrochaetus which are represented by tropical and subtropical M.sericus and M.collinsi and apparently cosmopolitan M.subquadratus and these occur in periphytic associations. Amongst species of Trichotria, T.pocillium is reported only by Edmondson and Hutcinson (1934) from Ladak while T.tetractis occurs widely in this country. Wolga spinifera was known to be distributed in Eurasia between 37*N-52*N (Koste, 1978); recent report of this species from India (Sarma, 1988), therefore, has considerably extended its distributional nmge.
Family Colurellidae
It comprises an im1'Ortant component (25 species) of Indian ploimid rotifers and is represented by three genera i.e., Colurella, Lepadella and Squatinella. Various works relating to their taxonomic studies from this country are by Edmondson and Hutchinson(1934), Wulfert (1966), Vasisht and Battish (1971), Lepadella ovalis and L.ptella are commonly encountered in planktonic collections while L.aspida and L.aspicora are biogeographically interesting speciers. Various examined taxa from acidic waters in India include Colurella, Sukata, Lepadella triptera, L.nartiangensis, L.patella elobgata, L.cristata and L.dactyliseta.
Family Notomma tidae
This important family of monogonont notifers is not adequately studied in India. It is represented by 26 species of which ten species were reported by Edmondson and Hutchinson (1934) and additional information is provided by Wulfert (1966), Dhanapathi (1975a) and Sharma (1979). Various bigeographically important species recorded from this country are Cephalodella mulea. C.panarisla and Eosphora anlhodis.
Family Gastropodidae
It is so far very poorly documented and most species were listed earlier by Edmondson and Hutchinson (1934) while endemic Ascomorpha saltans indica was described Crom Gujarat (Wulfert, 1966). Gaslropus hyptopus is an interesting species reported from India and is earlier known to be distributed in Europe, Eastern Asia and North America.
Family Proalidae
Amongst four genera of periphytic rotifers included in this family, only genus Proales is represented from India and remains poorly reported (only two species).Of these, P.decipiens is reported only by Edmondson and Hitchinson (1934) while endemic P.indirae is described by Wulfert (1966) from Baroda (Gujamt).
Family Trichocercidae
It is another important family of order Ploimida but includes only 19 species from this country; few valuable contributions dealing with these are by Edmondson and Hutchinson(1934), Wulfert (1966) and Sharma (1979). Trichocerca tropis comprises an endemic species; T.flagellata, described by Hauer (1937) from Tamil Nadu,is now known from Malaysia. T cyllindrica, T bTazieliensis, T slylala and T.rultneri are other biogeographically important members of this family documented from India.
Family Asplanchilidae
It includes predatory rotifers of genus Axplanchna: this genus is represented by widely distributed A. brightwelli which is also regarded as an eutrophic indicator while A. intemtedia and A.pridonta indicate restricted occurrence in this county. Genus Asplancltnopus includes A.multiceps from Ladak, A.hyalinus and A. bimavaraensis from Andhra Pradesh. The only karyological study from India (Rishi et. at., 1983) dealt with Asplonehno brightwelli and indicated acrocentric chromosomes of varying sizes (n = 16, 2n = 32).
Family S ynchaetidae
Various species of genus Synehaeta reported so far from India and two species of Polyarthra i.e., P. euryptera and P.trigla are examined only by Edmondson and Hutchinson (1934). P.longiremis documented by Naidu (1967) from Andhra Pradesh needs confmnation. Arora (1962) described P.multiappendieulata from Nagur and it is a synonym of P.vulgaris (refer: Koste, 1978) which is apparently widely distributed in plankton collections.
Family Dicranophoridae
This is an important family of order Ploimida but remains very poorly studied in India~ So far only six species of genus Dicranophorus and one species o( Eneentrum are documented from this country and infonnation about their occurrence is provided by Wulfert (1966), Dhanapathi (1975) and Shanna (1979). Of these, Dicranophorus epicharis, D.lutkeni and Encentrum longipes are of regional distributional interest.
Order Gnesiotrocha
It is divisible into two suborders i.e., Flosculariscea and Collothecaea which, inturn, include six and two families respectively. All these families are represented in India and contain 42 species belonging to 14 genera. Of these, Floscularidae contains 13 species (6 genera) and taxonomic information about these is primarily given by Anderson (1889), Edmondson and Hutchinson (1934), 'Wulfert (1966) and Sanna(1988). Ptygura stephanion and Sinantherina triglandularis comprise endemic elements. Of the other species, Ptygura tacita is known previously from North and South America while Sinantherrian socialis exhibits pantropical distribution. Some studies on colonialmembers of this family, particularly relating to life-history and colony formation,were undertaken by Bhardwaj and Duuagupta(1984) and Bhardwaj (1985).
Family Conochilidae is relatively poorly documented and included fewer species of genus Conochilus.. of these,C.dossuarius aselosus and C. orboreus are endemic to Indian Rotifera.
Genus Ilexarthra (Family Hexarthridae) includes only four species of which H. bulgarica and H. bulgarica nepalensis are biogeographically important.
Family Filiniidae includes five species of genus Filinia. Amongst these, F. opoliensis, F. longiseta and F. terminalis have frequently been listed in taxonomic contributions from this county. F. pejleri appears to be pantropical in its distribution. In addition, F. cornuta is documented by Sarma(1988) while F. longiseta saltator is examined recently from Bihar(Shanna ft. al., 1990). F. longiseta and F. opoliensis are regarded as eutrophic indicators by various workers from this country.
Family Testudinelljdae is represented by two genera i.e., Pompholyx and Testudinella. The fonner includes two species; of these, P. eomplanata is reported only by Edmondson and Hutchinson (1934) while the later appears to be ofconsiderable importance in plankton collections from various parts of this country. Genus Testudinella is represented by eight species (12 taxa) and amongst these Testudinella "bravieauda, T greeni, T. parva parva, T parva semiparva, T. parva bidentata and T. tridentata are recently documented from India by Shanna (1990).
Horaella brehmi (Family Trochosphaeridae) is a phylogentically interesting species of this family. It was represented earlier from North America, Sri Lanka, Australia, India (West Bengal, Bihar) and its distributional range is currently extended (Koste &Shiel, 1987) to 42* in Tasmania.
Family Collothecidae(Suborder Collothecacea) is represented by four planktonic species which were studied only by Amnderson (1889) from West Bengal.
Another family of the above suborder i.e., A trochidae is represented only by Cupelopagis vorax. This species was documented by Edmondson and Hutchinson (1934) and its male was described by Vasisht and Dawar (1~8). Super-order Digononta Order Edelloidea
All digonont rotifers are included in order Bdelloidea which remains so for very poorly studied from the Oriental region. It is represented by about 365 species belonging to 21 genera; of these, only 29 species spread over five genera known from India. Important taxonomic contributions to the members of the order wete those by Anderson (1889) and Murray (1906); the later dealt with the collections from moss which contained 27 species of bdelloids out of total 32 species examined by Murray. Rotaria rotaria and R. neptunia are occasionally noticed in plankton collections from highly eutrophic water bodies.
Current Studies
Very few specialists are now actively engaged in rotifer systematics in this country. The author and co-worker(Dr. Sumita Sharma, Eastern Regional Station, ZSI, Shillong) are currently studying faunas of the states of Meghalaya and Tripura in North-Eastern India. 'The author is examining collections from Orissa and Andaman and Nicobar Islands and has also initiated studies on the rotifer fauna of Bihar in collaboration with Dr. R.K. Sinha (Patna University). Besides, the author is preparing a monograph of Indian Freshwater Rotifera. An attempt is being made in this department to maintain national reference collections of this group and identification advisory service is extended to research workers of different Indian Universities and institutions. At the moment, some other taxonomic studies are conducted at Jiwaji University (Gwalior) and Kashmir University.
Ecological investigations have been taken up by various workers in routine limnological studies but serious ecological researches are carried at North-Eastern Hill University,Gauhati University, Calcutta University, Kalyani University, Punjab University, Patna University, Aligarh Muslim University, Jiwaji University and Freshwater Biological Station, ZSI, Hyderabad. In addition, investigations on autoecology and production are being attempted at Madurai Kamraj University and Delhi University.
Global studies on the rotirers are, however, much scattered from various classical, aspects to application of latest biotechnological methods. Different fields of these studies include systematics, biogeography, sessile and marine rotifers, community ,structure, ecology, distributional pattems(horizontaI and vertical), population dynamics, competition, effect of grazing and predation, feeding behaviour, escape response, ultrastructure, neuro-ethology, neurophamacology, biochemical aspects with special reference to nutritional value, effect of acidification, fertilization and eutrophication on community structure, bioessay and environmental toxicology experiments, population genetics, development of fast growing strains and intensive culture of rotirers as fish¬food for aquaculture practices.
Expertise India
In ZSI
S.G. PatH, Western Regional Station, Punc. Sumita Sharma, Eastern Regional Station, Shillong. S.V. Muley (Hydcrabad).
Elsewhere
S. Banerjee, &N.C. Dutta, Department of Zoology, University of Calcutta, Ballygunge Circular Road, Calcutta-700019, West Bengal. [Ecology ofplanktonic rotifers].
M.H. Balkhi, Department of Zoology, Govt. Degree College, Baranyka, Jammu and Kashmir. [Seasonal abundance, ecology].
Battish, &H.S. Sehgal, Department of Zoology, Punjab Agricultural University, Ludhiana, Punjab. [Taxonomy and ecology].
Bhattacharya, Department of Life Sciences, Tiripura University, Agartala, Tiripura. [Ecology of planktonic rotifers].
M.V.S.S.S. Dhanapathi, Department of Zoology, DNR College, Bhimavaram, Andhra Pradesh. [Taxonomy, distribution].
S.C. Dey, Department of Zoology, Gauhati University, Guwahati, Assam. [Zooplankton ecology].
B.Y .M. Gouder, Department of Zoology, Karnataka University, Dharwar, Karnataka. [Taxonomy and ecology].
Jana, Department of Zoology, Kalyani University, Kalyani, West Bengal. [Ecology of planktonic rotifers]. Chandra Mohan, Oepartment of Zoology, Andhra University, Waltair, Andhra Pradesh. [Taxonomy and ecology].
M.Y Qadri, Centre for Research for Development, University of Kashmir, Srinagar, Jammu and Kashmir. [Composition and ecological aspects]. C.K.G. Nayar, Department of Zoology, Christ College, Irinjalakuda, Kerala. [Taxonomy and ecology of planktonic rotifers].
Pant, &P.C. Sharma. Department of Zoology. Kumaun University, Nainital, Uttar Pradesh. [Composition and ecology]. Ramakrishna Rao, Department of Zoology. University of Delhi, Delhi. [Autecology, Population dynamics, production].
S.S.S. Sarma, Department of Animal Physiology, School of Biological Sciences, Madurai Kammj University, Madumi, Tamil Nadu. [Autecology, dynamics, production]. D.N. Saksena, School of Studies in Zoology, Jiwaji University, Gwalior, Madhya Pradesh. [Taxonomy, ecology, polymorphism]. B.K. Sharma, &R.G. Michael, Department of Zoology, North-Eastern Hill University, Shillong -793014, Meghalaya [Taxonomy and biogeography of Indian Rotifera, ecology, population dynamics, associations, trophic indicators]. A.R. Yousuf, P.G. Department of Zoology, University of•Kashmir, Srinagar, Jammu and Kashmir. [Composition and ecology]. H.S. Vasisht, Department of Zoology, Punjab University, Chandigarh, Union Territory. [Ecology, morphology , histology].
Abroad
H. Berner-Fankhauser, Zoologisches Institute, Universitat Bern, CH-3012, Bern, Switzerland. [Ecology, population dynamics, effect of sampling intervals].
R. Chengalatb, National Museum of Natural sciences, National Museum of Canada, Ottawa, Canada. [Taxonomy and distribution].
P. Clement, Equipe Neuro-Ethologie, Universite Lyon 1, 69622 Villeurbannc Cedex, France. [Ultrastructure, phylogenesis, Neuro-ethology].
M. V. De Ridder, van Malderlaan, 37/3, B-1710, Diclbeek, Belgium. [Systemayics, ecology, biogeography] .
H. Dumont, Institute of Ecology, State University Gent, B-9000, Gent, Belgium. [Systematic, ecology, indicator value, competitive potential, distribution].
A. Duncan, Department of Zoology, Royal Holloway College, Surrey TW20 9TY, U.K. [Ecology, population dynamics].
W.T. Edmondson, Department of Zoology, University of Washington, Seattle, Washington, U.S.A. [population dynamics, productivity].
Fernando, Department of Biology, University of Waterloo, Waterloo, Ontario, Canada. [Systematics, composition of tropical]. Gilbert, Department of Biological Sciences, Dartmouth College, Hannover, New Hampshire,
[Competition, Predation, Polymorphism, effect of tocopherol]. Green, School of Biological Sciences, Queen Mary College, London, U.K. [Systematics, ecology of tropical rotifers]. Gulati, Limnological Institute, Vijverhof Laboratory, Nieuwersluis, the Netherlands. [Ecology, dynamics, food and feeding]. Herzug, B'iologische Station Neusiedlersee, A-7142, Ikllmitz, Austria. [Ecology, population dynamics]. Hofmann, Max. Plank Institut fue Limhologie, 2320 PIon, Germany. [Taxonomy, ecology, population dynamics].
C.M. James, Kuwait Institute for Scientific Research"Mariculture and Fisheries Department, Salmiye, Kuwait. [Intensive rotirer culture]. King, Department of Zoology, Oregon State University, Oregon, U.S.A. [Population genetics, molecular evolution, adaptations]. Koiste, Ludwig-Brill-Strasse 5, D 4570 Quakenbruck, Germany. [Taxonomy and distribution of monogonoot rotifers].
Kutikova, Zoologivsl Institute of Academy of Sciences, Leningrad B-34, U.S.S.R. [Systematics, ecology, phylogeny, functional morphology]. May, Institute of Terrestruak Ecology, Penicuik, Midlothian, Scotland. [Taxonomy, ecology, dynamics].
Miracle, Dept. Ecol. Fac. Cien. BioI., Universidad de Valencia, Valencia, Spain. [Niche structure in seperate basins, sexual periods, ecology, variability]. Nogrady, Department of Biology, Queen's University, Kingston, Ontario, Canada. [Taxonomy, associations, neuropharmacology]. Pejler, Institute of Limnology, Box 557, Uppsala, Sweden. [Taxonomy, ecology, distribution, trophic indicators, substrate choice].
Pontin, 26, Hermitage Woods Crescot, St. John's Working, Surtey, England. [Distribution, ecology, keys to British Rotifera]. Ricci, Department of Biology, University of Torino, Torino, Italy. [Taxonomy, ecology, biology of bdclloids].
Ruttner-Kolisko, Biologische Station, A-3293, Lunz am See, Austria. [Taxonomy, ecology, population dynamics, metabolism, life-histories].
Shiel, Murray Darling Freshwater Research Station, Albury, N.S.W., Australia. [Taxonomy, ecology, distribution]. T. Snell, Division of Science and Mathematics, University of Tampa, Tampa, Florida, U.S.A. [Isolating mechanisms, genetics, population dynamics]. Starkweather, Department of Biological Sciences, University of Nevada, Las Vegas, Nevada,
[Feeding, Predation]. Sudzuki, Nihon Daigaku, Higashi-Arai, Omiya-shi, I-saitama-Ken, Japan. [Systematics, distrjbution, ecology, affinities].
Turner, Department of Invertebrate Zoology, National Museum of Natural History, Smithsonian Institute, Washington DC, U.S.A. [Taxonomy and distribution]. Wallace, Department of Biology, Ripon College, Ripon, Wisclnsin, U.S.A. [Sessile rotifers, ecology, dynamics].
Selected References
Bartos, E. 1959. Virnici -Rotatoria. Fauna CSR t Prahat 15: 1-969. Donner, 1. 1965. Ordnug Bdclloidea (Rotatoria, Radertiere). Bestimmungsbucher Zur Bodenfauna Europast Licfcrung 6. Akademia Verlag, Berlin. 297 pp.
Edmondson, W. T. 1959. Rotifera. In: Fresh waler Biology (Fds.ll. B. Ward and G. C. Whipple). John Willey &Sons Inc. New York: 420-497.
Edmondson, W. T. &Hutchinson, G. E. 1934. Report on Rotatoria. Article IX. Yale North Indian Expenditition. Mem. Conn. Acad. Artrs Sci., 10 : 153-186. Koste, W. 1978. Rotatoria~ Die Radertiere Mittcleuropas. Begrundet von Max Voigt. Uberordnung Monogononta. Gcbrilder Bomtraeger, Berlin, Stuttart. I. (Textbd: 1-673), II. (Tafelbd: T. 1-234).
Kutikova, L. A. 1970. Rotifer Fauna of USSR. Subclass Eurotatoria (in Russian). Fauna USSR, 104, N<ad Nauk, Leningread. 744 pp.
Ruttncr-Kolisko, A. 1974. Plankton Rotifers. Biology and Taxonomy. Supple Ed. Die Binnengewasser XXVI(I) : 1-146. E. Schwcizerbart sche Vcrlagsbuchranlung, Stuttgart. Sharma, B. K. 1987a. Indian Brachionidae (Eurotatoria : Monogononta) and their distribution. Jlydrobioiogia, 144 : 269-275.
Sharma, B. K. 1987b. Rotifera: Eurotatoria: Monogononta (Freshwater). In: Fauna of Orissa: Slale Fauna Series, 1(1) : 323-340. Publ. by Zoological Survey ofIndia. Sharma, B. K. &Michael, R. G. 1980. Synopsis of taxonomic studies on Indian Rotatoria. I-/ydrobiologia, 73 : 229-236.
Wulfcrt, K. 1966. Rotatoricn aus dcm Status Ajwa und der Trinkwasser"":Aufbercitung der Stadt Baroda (Indien). Limnologica (Berlin), 4 : 53-93.
Voigt, M. 1957. Rotatoria, Die Radcrtierc Mitteluropas. Bcrlin-Nikolasse. I. Textbd (1-508), II. Tafclbd. (T.I-lI5).
