Reptilia: India
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Faunal Diversity in India: Reptilia
This is an extract from FAUNAL DIVERSITY IN INDIA Edited by J. R. B. Alfred A. K. Das A. K. Sanyal. ENVIS Centre, Zoological Survey of India, Calcutta. 1998 ( J. R. B. Alfred was Director, Zoological Survey of India) |
Introduction
Reptiles are cold-blooded vertebrates which breath by lungs throughout their existence and have the body covered by scales; the skull articulates with the vertebral column by a single median occipitial condyle. By this combination of characters reptiles can be distinguished from all other vertebrates. They were the dominat group of vertebrates during the Mesozoic period and they reached their maximum and most diversified development at that time. Most of the orders of reptiles were established by the end of Triassic and some became extinct at that time. Of the 19 orders of reptiles 4 survive today. These are (i) Crocodylia (Gharials and Crocodiles); (ii) Testudines (Turtles, Tortoises and Terrapins); (iii) Squamata (Lizards and Snakes) and (iv) Rhynchocephalia which includes a single living species, the Tuatera (Sphel1odol1 pZl11ctatlts) found only in New Zealand.
The reptile fauna of India is unique in its diversity. Among its components are elements that have the greatest affinity to the Oriental region, as well as others, showing close relationship to the Indo-Malayan region. Reptiles in India are found in environments ranging from deserts to the rain forests, from the brackishwaters and beaches fringing the coasts of plains, hills and dense jungles. Crocodiles are large, lizard-like amphibious reptiles found in immediate proximity to large lakes, swamps, marshes and rivers. The heavily armoured body, with its long and strong muscular tail, is well adapted to rapid swimming. With the eyes, nostrils and ears situated on top of the head, crocodiles can see, smell and hear while lying almost completely submerged. A fleshy valve in the throat closes the windpipe at the back, thus enabling the reptile to open its mouth and hold its prey under water. Crocodiles are carnivorous animals and relish meat or flesh. They are oviparous, laying several dozens of hard-shelled eggs in shallow excavations near the water edge.
Turtles are the only reptiles which have a shell. The characteristic dome¬like shell, which serves as a protective armour of the turtle, is composed of two parts : an arched upper part called carapace, and the flat lower part, plastron, joined on either side by a bony bridge. Turtles are toothless but they have a beak with horny sheaths. They chew their food only to reduce it for swallowing. They are omnivorous, and like other reptiles, can survive without food for months. Although they are proverbially slow in movement, the turtles are powerful swimmers. All turtles nest on land. They vary greatly in size from a 300 mm long dwarf to 1.8 m long giants. The varied usuage of the words "turtle" and "tortoise" in English has given rise to much confusion. In proper usuage, "tortoise" refers to the strictly land dwelling species with elephant-like stubby feet and "turtles" are the aquatic fonns inhabiting the sea, rivers and ponds with either flippers or webbed toes.
Lizards, characterised by a short body with four well-developed limbs, a short, flat tongue and an external ear-opening. Some limbless lizards which have elongated bodies are snake-like in appearance but they can be identified by their distmctive ear openings and movable eyelids which are quite foreign to the snakes. The tongue of a lizard is employed as a device for lapping up the prey and also as a sensory organ. The ability to shed the tail and regenerate a new one in its place is possessed by geckos, legless lizards and skinks. Most of the lizards can change colour, depending on the light, temperature, and the mood of the animal. Males are larger, quarrelsome and brilliantly coloured than females. Lizards principally feed on insects and small animals. In size, Indian lizards range from a 5 cm long skink to the 2.5 m long Water Monitor (Varanlts salvator). There are no venomous lizards in India.
Snakes possess elongated bodies which are covered with overlapping scales which may be either smooth or keeled. They lack movable eyes and functional legs. They do not have external ear-openings and so they cannot hear in the nonnal way. They can, of course, pick up the earth-borne sound vibrations through their sensitive bodies. The flicking forked tongue is hannless and it is mainly employed as sensory organ. The teeth are needle¬like and pointed backward, which enable the snake to grab the slippery prey. Poisonous snakes have hypodennic needle-like fangs which are in fact the modified front teeth used for injecting the venom when the snake strikes. All snakes hunt and eat live animal prey. The youngs are miniatures of the adults. The largest snakes of India are the Reticulated Python which grows to be 10 m long and the king Cobra which attains the record length of 5 m for a poisonous snake in the world. The smallest are the blind snakes some of which are less than 30 cm in length. Of about 240 species of snakes of India, some 52 species are venomous in nature.
STATUS OF THE TAXON Global and Indian status A comparison of the global and Indian reptilian diversity as per available information is shown in Table -1. Tilble -1 Clilss Filmilies (N) Species (N) World Indiil World Indiil
According to a recent estimate the countries leading in possessing a rich and diverse reptilian fauna are Mexico, Australia, Indonesia, Brazil, Colombia, India, Ecaudor, Peru, Malaysia and Thailand in that order. A brief synopsis of the composition of the reptilian fauna of India is given in Table -2. Table-2
Disturbution
Among the components of Indian reptilian fauna are representatives that have the greatest affinity to the Oriental Region, as well as others influenced by the Indo-Chinese and Indo-Malayan areas. The climate, varying vegetation and the soil of India offer a great range of biotopes for the highly diverse fauna of the reptiles in India. It is not surprising then that the pockets recording a heavy rainfall with a canopy of thick rain forests such as the Western Ghats, northeastern India and the Andaman and Nicobar Islands hold between them the lion's share of India's lizards and snakes. Almost the entire snake family, Uropeltidae (33 species) comprising the primitive burrowing snakes is restricted to the Western Ghats. Some 67 genera and nearly 56 genera of Indian reptiles are found in the Western Ghats and rainforests of northeastern India.
The Marsh or Freshwater Crocodile (Crocodylus palustris) is the most widely distributed of all the Indian crocodiles as it is a highly adpatable species being found in stagnant waters, jheels, reservoirs, tanks and rivers with placid current, throughout India. Though it is called "Marsh crocodile" it is reported from the Himalayan foothills as well as the arid tracts of Rajasthan. Its present breeding populations are found in Airan Lake, Gir Sanctuary (Gujarat) and Amaravathi Reservoir (Tamil Nadu). The Indopacific Crocodile «(roeodY/lIs poroslIs) is restricted to parts of the east coast of the States of Orissa and West Bengal (Sunderbans) and to some pockets of the Andaman and Nicobar group of Islands. The Gharial (Gavia/is gangetiells) is mainly an inhabitant of the fast-flowing rivers of northern India. It presently is found in the Indus, Ganges, Brahmaputra and Mahanadi and extends its range outside India to Nepal, Bangladesh, Burma and Pakistan.
Barring five species of marine turtles which nest on our coasts, of the remaining 25 species, a majority of the emydid and softshelled turtles inhabit mainly the rivers of northern India. The land dwelling tortoises are confined to the hills of eastern India and Western Ghats. The Gahirmatha beach of Orissa is reckoned as the world's largest rookery for the Olive ridley (Lepidoeltelys olivaeea). The Cochin (Kavalai) forest cane turtle (Geoemyda silvatiea), which was supposed to have become extinct as it was not collected since its discovery in 1911, has been collected in 1982 again. The critically endangered river turtle (Batagllr baska) is found in the estuaries around the Sunderbans of West Bengal. Available information on distribution of lizards shows that the Eastern Himalayas and the forests of the Western Ghats closely followed by the Western Himalayas are homes to more than two-thirds of the lizard fauna of India.
Snakes, as a major group of reptiles, are widely distributed all over India from the higher elevations of the Himalayas to the land's tip in Kanyakumari. They live on and below the ground, in trees and in fresh as well as salt water.
Biological Diversity And Its Special Features
Of the three species of Indian crocodiles, the mugger «(roeody/lls pa/llstris) and the Saltwater crocodile «(roeodY/lIs poroslls) look very much alike and are distinguishable only on the basis of proportions of the snout after they are fully grown. However, the gharial (Gavialis gangetiells) can be rather easily recognised by its unique extremely long and slender snout. The turtles of India exhibit remarkable capabilities of modification to suit their existence in different niches such as the sea, rivers, plains and forests. Apart from the characteristic bony shell, marine turtles have paddle-like limbs. The freshwater turtles or terrapins have hard shells and partially webbed feet whereas the soft shells have a disc-like shell covered with soft skin, tubular nostrils and fully webbed toes. The land tortoises have high-domed carapaces and blunt elephant-like webless feet in keeping with their terrestrial habits. As for the lizards and snakes which are Widely diversified. The shape of the body gives the clue to the habits of the species. While a majority of the lizards are characterised by well-developed limbs, a few which lack them can be differentiated from snakes by the presence of eyelids. Snakes have elongate bodies and lack limbs, eyelids and an external ear-opening all of which are characteristic features of a typical lizard. The adaptive radiation is best shown by the huge assemblage of snakes of the major family Colubridae. As might be expected of such widely distributed snakes the Colubrids are found in a wide range of habitats, some are terrestrial, some fossorial, some aquatic, and some estuarine. The snakes of the families Elapidae, Hydrophiidae and Viperidae are highly venomouS. The fangs of the cobra and its allies, such as, the krait, the coral snake and the sea snake are short, grooved and immovably fixed to the front of the upper jaw while the fangs of a viper are long foldable and can be erected at the time of striking.
The lizard fauna of India is moderate in terms of diversity on a world wide basis. There are no venomous lizards in India. That the reptilian fauna of India is mainly dominated by Indo-Chinese element is a well known fact. As regards the lizard fauna, it can be found that the eastern Himalayas and all the northeastern States of India are profoundly influenced by the Indo¬Chinese connection. A most significant peculiarity is the discontinuous distribution exhibited by the genus Draco ('flying' lizards) whose present day representatives are found in eastern India and again in the Western Ghats with a wide intervening gap. Likewise, the skinks of the genera Dasia, Lygosoma, and Scincella have the same or allied species occuring in the eastern India and Western Ghats. The richest concentration of lizard fauna is in two regions of India namely the Eastern Himalayas and Western Ghats. The lizard fauna of the Nicobar Islands exhibits its Malayan affinity in the presence of a sole representative each of the genera Ptychozoon ('Flying' Geckos) and Dibamus (Worm Lizard).
The geckos (Family Gekkonidae) are hardy reptiles which can survive long periods without food and are often transported in the cargo of ships. The presence of some geckos such as Cnemaspis kandiana, Gehyra mutilata and LophopllOlis scabriceps in India is probably due to their introduction through human agency. The snake fauna of India comprises elements from three zoogeographical regions namely the Oriental, Indo-Chinese and Indo-Malayan with some entrants from outside these regions. The majority of the primitive burrowing snakes with modified tails of the Family Uropeltidae are to be found only in the various hill ranges of Western Ghats with only 11 out of 44 species known, being found in Sri Lanka and nowhere else in the rest of the globe. Likewise, the five species of the Oriental Worm Snakes included in the Genus Tracllisc1lium found in the Eastern and Western Himalayas are a unique addition to the snake fauna of India. The rare Egg-eating snake Elacllistodon westernmanni, the second species of the Family Dasypeltidae, is another peculiar and interestirig addition. It is reported from a few pockets in the districts of Purnea (Bihar) and Jalpaiguri (West Bengal). The genus of hill species, Xylophis, confined to the Western Ghats of India and found nowhere else in the world is yet another interesting addition to the snake fauna of India.
Endemic And Endangered Species
All the three species of Indian crocodiles are now listed as endangered. Among the turtles, the edible species are severely threatened while the land tortoises have become scarce. The River terrapin seems to be critically endangered. The four monitor lizards of India are declared endangered. However, the status of several species of Indian lizards, such as, the spinytails and sand-living skinks are also causing concern. According to a recent study by Murthy and Sanyal (1993: 'Rare Snakes of India' The Snak~ 25) some seventy species of Indian snakes are either extremely uncommon or rare and the distribution and status of nearly 17% of the known snake fauna is rather uncertain and is in doubt.
The Golden Gecko (Calodactylodes aureus) found in the Eastern Ghats is a unique species endemic to India. The four endemic species of the Cat Skinks of the genus Ristella restricted in their distribution to the Western Ghats are unique addition to the family Scincidae. Likewise, among the agamid lizards (Fam. Agamidae), mention should be made of the Fan¬throated Lizard (Sitalla pOllticerialla) and the Rock Lizards of the genus Psammophilus which are unique to India. The Barkudi burrowing skink (Barklldia inslllaris), which can be reckoned as the world's most endangered skink, is a significant and interesting addition to the lizard fauna despite the fact that it has become scarce, even in the type-locality.
Some threatened species of reptiles in India is listed in Table -3. MURTHY &< RAVICHANDRAN : Reptilia Table -3 Some threatened Reptiles in India Group Family Species Crocodiles Hardshelled turtles Softshelled turtles Lizards Snakes Gavialidae Crocodylidae Dermochelyidae Cheloniidae Bataguridae Trionychidae Varanidae Boidae Colubridae Gavialis gangetiells Croeodyllls poroslIs, Croeodyllls palllstris Dermoclrelys coriacea Caretta caretta, Clrelonia mydas, Eretmoelrelys imbrieata, Lepidoclrelys olivacea Batagllr baska, Kacllllga tecta Lissemys pllnetata, Aspideretes llllTllm, Aspideretes gangetiCIIs Varanlls salvator salvator, Varanlls bengalensis, Vamnlls flaveseens, Vamnlls griseus koniczmyi Pytlron molllrlls molllnls, Pytlron retielilata Elaclzistodon westernmanni
Value
Reptiles are a most important group of predators, the interaction of which maintains the natural balance in the forests and deserts, rivers and lakes and the plains and hills of India. Crocodiles are master predators and play a key role in recycling of nutrients. The role played by the crocodiles in keeping down the populations of predatory fishes in our lakes, estuaries and river systems can not be overemphasised as studies of some crocodiles, such as, the gharial proves. The Indian gharial is found to prey on 'Goonch', the greatest destroyer of eggs and young of the commercially important fishes of the Gangetic system. When crocodiles are absent predatory fishes multiply and consume all the smaller fishes of commercial value and adversely affect the fishery interests. Turtles are not mere animals for worship but they playa vital role in keeping a check on the growth of water weeds as otherwise the unchecked weed growth can be disastrous to the aquatic life. Some species found in the major rivers of India used to feed upon the half-burnt human corpses which helped in the recycling of nutrients and keeping the river system clean. Lizards and snakes mostly feed on different kinds of insects including the pest species. The monitor lizards are efficient destroyers of the coconut pests like crabs, beetles and snails. By eating insects, rat and mice, many of which may carry disease and damage crops, snakes perform a major ecological role. There is no vegetarian snake in nature and hence the feeding habits of snakes are of more than passing interest to us. Because of their mode of life and feeding habits snakes are perfectly suited to follow the rat down to its hole and finish off both the young and adult alike. The venomous snakes are kept in captivity for the production of antivenin and other medical purposes.
In his quest for food man has not spared the reptiles. Since time immemorial turtles, of all the reptiles, gained culinary importance and provided staple diet to man. The Green sea turtle is a rich source of protein. Freshwater tortoises of the genera, such as , Hardella and Kacllllga and river turtles of the genus Aspiderates found in the Ganges and Brahmaputra river systems are captured in large numbers for food. The eggs of monitor lizards are a great delicacy and the animals themselves provide a wholesome meal. 1)le spiny-tailed lizard, Uromastix hardwickii is considered good for eating and specially the curious tail of the lizard is most favoured. The demand for .the reptilian-derived skin, in particular the crocodiles, monitor lizards and the rat snake is so well known that it needs no mention here. The monitor lizards and some curious-looking forms have become "medicinal" species because of the purported value of their fat as medicine for curing human disorders. Thus, the preparations made from the visceral fat of the monitors, spinytails and some desert-dwelling skinks are said to be effective as aphrodisiacs.
Threats
A great number of living reptiles of India, are slowly disappearing mainly due to the increasing human interference. Not only are reptiles deprived of their habitats but their direct persecution and slaughter are intensified by the rapid growth of industrialization and land exploitation.
With the growing demand for their skin, ruthless killing of the harmless as well as the venomous kinds of snakes continue unabated. So much so, in some parts of the country the entire populations of some of the formerly abundant species, such as, the Rat Snake are wiped out. In India yet another natural hazard is the devastating forest fire. Snakes seem to make little attempt to escape when a forest fire is about to engulf them. In the circumstances we do not know how many species of snakes disappear from the scene if the whole of the bIotope is destroyed.
Crocodiles are primarily threatened by the gradual destruction of their habitat and hunting for their skin. A lesser but a cause for concern is the egg collection for food and occasional killing of crocodiles indulged by some tribals notably in the Andaman and Nicobar group of Islands. The destruction of mangroves for converting them into rice fields has severely limited the survival chances of the vanishing Indopacific crocodile. The depletion in the populations of the gharial is the direct consequence of huge dams and barrages constructed over the reptile's abode-the River Ganges and its tributaries. The fishermen have also turned adversaries of crocodiles because they complain the depletion in their catches is due to the presence of crocodiles in the traditional fishing grounds.
Turtles of all kinds are on the decline now because of their direct persecution in their habitat by man. The meat and eggs of all species are edible and their skin is valuable. The other factors that endanger the turtles are the effects of deforestation, pollution and destruction of habitat. The environmental pollution, has had unforeseen effects on the water systems, particularly such as the River Ganga. The accumulation of the stinking human corpses/half burnt bodies in the absence of natural scavengers in water like the turtles, is causing a serious hazard not only to the aquatic life but also to the inhabitants on the banks of the river. The clearance of their original habitats, the destruction of virgin forests and their indiscriminate killing/capture are the chief factors responsible for the decline in the lizard fauna of India. The famous herpetologist, Malcolm Smith, has as early as 1935, warned of the severe consequences that might eventually lead to the disappearance of the giant lizards such as monitors if the trade in the lizard's skin continues unabated. True to his words the skin trade has today drastically reduced the abundant populations of all the Indian monitor lizards. The unabated exploitation of the monitors and the spinytailed lizards for their edible meat and medicinal fat is another grave threat facing these reptiles.
The IUCN's list of threatened animals (1988) includes the Indian Python (Python molltrlts ) as 'Vulnerable' and the Acellate Cobra (Naja oxiana) as 'Endangered' The Indian Wildlife (Protection) Act, 1972 accords protection to the Pythons and the Indian Egg-eating snake (Elaclliston westermannO. But the populations of the once abundant Rat snake (Ptyas ml/cocoltS ) and the common cobra (Naja l1aja) have been greatly reduced because of the demand for their skin in international market. The populations of several rare hill species of snakes are depleted with the gradual loss in the forest cover for them. To illustrate an example the author in a study of over two decades could collect only 21 species of the unique burrowing snakes of the family Uropeltidae (Shieldtails), confined to the Western Ghats. However, the literature records that the Western Ghats are home to as many as 33 species of these snakes. Like the Uropeltids, the status of several species is in doubt and we do not know how many of them have become extinct.
Conservation Strategies And Future Studies
Since the survival of reptiles, which are closely associated with our religion, art and culture is of paramount importance we have to initiate additional conservative measures over and above the steps taken by the Government in affording protection to several reptiles under the Indian Wildlife (Protection) Act 1972 and by clamping a total ban on the capture killing of some rare species. While it can now be safely assumed that the crocodiles are given a fresh lease of life thanks largely to the conservation measures initiated by the Government and the captive breeding programme undertaken by the Madras Crocodile Bank, it should be realised that the wild habitats of these reptiles should continue to be protected. It is also suggested that suitable areas for the purpose of breeding and restocking of the crocodiles should be identified. As for the conservation of sea turtles, any activity that hampers the breeding cycle of the species visiting our coasts should be avoided. Also, the sea turtle nests should be protected from both the man and the beast. It is also essential to involve local people and seek their cooperation in protecting the turtle habitats. A significant strategy aimed at conserving the unique lizards and snakes is the creation of nature reserves for them in remote regions inaccessible to man. In areas of this kind, it is still possible to preserve whole ecosystems in which all reptiles have their appropriate niches. Most important is public education to make the people aware the value of reptiles and their relevance to mankind. Despite the legal protection afforded to the reptiles and the increasing awareness among the educated public about the beneficial role played by the reptiles in nature the real problem is that we have yet to make the layperson realise that the reptiles are an integral part of the environment and that they too are part of the biological resources that can be renewed.
Selected Reference
Constable, J. D. 1949. Reptiles from the Indian peninsula in the Museum of Comparative Zoology. Bull. Mus. compo zool. Harv. Univ., 103 : 59-160. Daniel, J. C. 1983. The Book of Indian Reptiles. Bomaby Natural History Society. Deoras, P. J. 1965. Snakes of India. New Delhi: National Book Trust. Murthy, T. S. N. 1985. A field guide to the lizards of Western Ghats. Rec. zool. Surv. India, Oee. Paper, 72. Murthy, T. S. N. 1986. Tire Snakes Boom of India. International Book Distributors, Dehra Dun. Smith, M. A. 1931. The Fauna of British India, including Ceylon and Burma. Reptilia and Amphibia-Loricata, Testudines. 1 : xxviii + 185 pp. London: Taylor and Francis. Smith, M. A. 1935. The Fauna of British India, including CelJlon and Burma. Reptilia and Amphibia-Sauria. 2 : xiii + 440 pp. London: Taylor and Francis. Smith, M. A. 1943. The Fauna of British India, including Ceylon and Burma. Reptilia and Alllphibia-Serpentes 3 : xii + 583 pp. London: Taylor and Francis. Tikader, B. K. & Sharma, R. C. 1985. Handbook of Indian Testudines. xii + 152 pp. Calcutta: Zoological Survey of India. Whitaker, Romulus, 1978. Common Indian Snakes-A Field guide. xiv + 154 pp. New Delhi : Macmillan Company of India Ltd.
Reptilia
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Introduction
The reptilian fauna of India is very rich in its composition and constitutes a major component of the Indian vertebrate fauna, comprising three species of crocodiles, 32 species of turtles, 156 species of lizards and 237 species of snakes (See Table I). Reptiles are the most important group of predators, which maintain the natural balance, but very few people realise their importance. One of the reasons that people are wary of reptiles is that some snakes are poisonous, or a few crocodiles may at times turn into man eaters. Out of nearly 428 species of reptiles inhabiting India only the saltwater crocodile (Crocodylus porosus) and five kinds of snakes, namely, the common cobra (Naja naja), King cobra (Ophiophagus hannah), the common krait (Bungarus caeruleus), the Russell's viper (Vipera russelli), and the saw-scaled viper (Echis carinatus) are harmful. It is gratifying to note that more and more people are now interested to know about the reptiles, their natural history and role in the environment and to distinguish the poisonous snakes from the non¬poisonous varieties. It is hoped that the newly generated awareness of the variety and richness of our reptiles change the attitude towards them whose survival is of paramount importance in the delicate balance of nature.
Man and Reptiles
Most lizards feed on different kind of insects including the pest species. Snakes consume rats and mice. Snake venom is used in the production of antevenom -an anecdote for snake bite. Crocodiles and turtles feed on the dead and decaying matters thus keep the water free from pollution. Of all reptiles, turtles are of great economic benefit to man because several freshwater turtles form the staple diet in India. The sea turtle, Chelonia mydas has gained worldwide reputation because of its culinary importance. The Hawksbill, Eretmochelys imbricata is killed in large numbers for its beautiful shell.
Historical Resume
Genemi
The study of reptiles has been pioneered and persecuted in the early eighteenth century by the British Naturalists while serving in the then Indian Medical Service (IMS) 01" the Indian Forest Service (IPS). Their papers were published mostly by the Trustees of the British Museum, London.
The monumental work on Indian reptiles, published nearly a century ago are 'The Reptiles of British India' by Gunther (1864), 'Descriptive Catalogue of the Reptiles of British India' by Blyth (1876) and 'The Fauna of British India: Reptilia and Batrachia' by Boulenger (1890). Nevertheless, it was not until sometime later that information about these animals really began to accumulate in India and a few but serious workers started building up the edifice of the Indian Herpetology brick by brick. Smith's (1931, 1935, 1943) volumes stood the test of time and they constitute the standard work of reference on the subject.
Herpetologists have never been numerous in India. One reason is that this branch of natural history is never popular and another is the prevailing prejudice against creatures some of which are clammy and cold to touch, while some are poisonous. The lack of future openings for the herpetologists has also contributed to the utter negligence of the subject at the university level. However, there has been a dramatic upsurge in the studies in recent years. Group-wise Analysis
Crocodiles: The systematics and biology of the Indian crocodiles are fairly known by the work of Abercromby (1922), Barton (1929), Boulenget (op. cit.), Ferguson (1891), Gadow (1901) and Smith (1931).
Turtles: The foundation for the primary investigations on the chelonians (testudines) of India was fmnly laid by Gray (1825-1875) who has admirably combined the osteological features and taxonomic characters of these animals in this work. Annandale (1912-1915) carried out detailed investigations on the systematics and distribution of the tortoises and mud-turtles found in the inland waters of India. Chaudhuri (1912) and Prashad (1914) continued the work initiated by Annandale (op.cit.). Studies on sea turtles occuning in the coastal waters of India and their nesting grounds were neglected till Smith (1931) focussed our attention on these giants among the sea reptiles.
Lizards: The systematics and distribution of the saurian fauna of India has been worked out by earlier naturalists like Anderson (1871-1872), Guenther (1864-1875), Murray (1884-1887), Stoliczka (1870-1873) and Annandale (1904-1921). Among these, Annandale occupies a prominant place for his investigations based on the rich material deposited in the Indian Museum, Calcutta. Blyth (op. cit.) carried out his work on the lizards deposited at the Royal Asiatic Society of Bengal, Calcutta. Stoliczka (op. cit.) paid special attention to the lizards of Andaman and Nicobar Islands which harbour a variety of species more intimately connected with the Malaysian subregion. Hora (1924) published a series of papers on the lizards of the major families deposited in the collection's of the Zoological Survey of India. He also described the mechanics of the adhesive apparatus of some geckos and made a comparative study of the suction pads found on the toes of certain anurans. Beddome (1870-1978) has studied the lizards of the Western Ghats. Annandale and Blyth (op. cit.) should be credited with the discovery of several new skinks and agamids. Ganapati and Rajyalakshmi (1953) studied the binomics of the rare limbless skink, Barkudia insularis. Snakes: In the early seventeenth century, a scientific study on the structure, habits and life¬histories of the Indian snakes was' taken up by British naturalists. They were indefatigable in their researches in collection, figuring and describing these interesting reptiles of India and their work and collection provided the unshakable foundation for modem ophiology. Mahendra (1935) has presented a scholarly review of the history of Indian Ophiology.
The earliest scientific references to the Indian snakes available must be credited to Patrick Russell, who may most appropriately be hailed as the 'father of Indian Ophiology' He has for the frrst time distinguished the venomous from the nonvenomous snakes of India. His two volumes on Indian Snakes (1796, 1801-1809) bears his stamp of authority on the subject at the time. Fayrer (1874) carried out detailed investigations on the physiology of venom of Indian snakes. Gunther (1864) set the trend for the future ophiological studies on the Indian serpents on scientific lines by publishing his major work on 'The Reptiles ofBritish India' George Albert Boulenger's classic work is familiar to the herpetologists of India and elsewhere. His major work entitled 'Fauna ofBritish India-Reptilia and B4trachia' (1890) set the course for modem ophiology of India. He prepared exhaustive keys for easy recognition of Indian snakes. Indian ophiologists owe a deep debt of gratitude to Beddome (1863-1886) for his work on the obscure uropelti~ snakes of South Indian hills. Wall literally domina,led the field of Indian ophiology for an uninterrupted period of 2S years in early twentieth century.
His major contributions are 'The Poisonous Terrestrial Snakes of our British Dominions' (1928), and 'A popular Treatise on the common Indian Snakes' (1905¬1919). Among the early Indian herpetologists devoted to the study of snakes, Mahendra and Gharpurey stand out. Mahendra (1939) has contributed towards a better and clear understanding of the zoogeographical distribution of Indian Snakes and their similarities with the fauna of'the neighbouring countries in the subcontinent. It was Colonel Gharpurey (1935) -a medical man turned Ophiologist -who attempted for the first time in India to dispel the ignorance and superstitions woven around the Indian snakes by writing a popular book entitled 'Snakes of India'.
Studies from Different Environs
Investigations on the reptiles of India have for a long time been concentrated on survey, identification and publication of the taxonomic accounts of the species recorded. ZSI, which is a repository of the vast assemblage of the ophidian collections from all over the subcontinent provides excellent opportunities for tax.onomic studies.
Taking advantage of the rich National Zoological collection ~oused in the ZSI and the material obtained from the exploratory surveys carried out from time to time in the nook and corner of the country, specialists continue to publish their findings. With the setting up of the biosphere reserves and declaration of some reserve forests as conservation areas, the last one and a half decades have seen an upsurge in ecological work on Indian reptiles. While continuing the routine survey work the specialists of the ZSI and those associated with the other organisations like the Bombay Natural History Society have been paying serious attention to the reptiles of the Wildlife Sanctuaries, National Parks and Biosphere Reserves. Studies have be'en completed by the scientists of ZSI on the reptile fauna of West Bengal, Orissa, Goa, Rajasthan, Andaman and Nicobar Islands and Tamil Nadu.
Likewise, the studies on the reptiles occurring in the Rajaji National Park. Namdapha National Park, Arunachal Pradesh, Kalakaddu Hills of Tamil Nadu have been completed. The reptile fauna of the Chilka Lake has been investigated and the study completed. Though a lot of work has been done on the reptilian fauna of India, yet a wide area remains to be investigated. There is still scope to study the reptilian fauna of Meghalaya, Mizoram, Arunachal Pradesh, Sikkim and Manipur in the Eastern Himalaya, Telangana and Rayalaseema regions of Andhra Pradesh, Marthwada area in Maharashtra and the various hill ranges comprising the Eastern Ghats. Likewise, the reptile fauna of the estuaries and mangroves needs special attention. The turtle fauna of the peninsular rivers is little known. The systematics and biology of the sea snakes occurring in the waters of India are far from complete.
Estimation of Taxa
India's reptile fauna is rich, varied and unique. A great number of them are endemic and relict forms. As Blanford (1901) remarked, there are a few, if any, regions on the earth's surface that exceed in reptile fauna than of India in area of interest Two regions namely, the Eastern Himalaya and the Western Ghats are herpetologically rich areas. The reptile fauna of India is largely dominated by Indo-Chinese element. Some 428 species of reptiles belonging to 137 genera and 26 families occur in India. A group¬wise critical estimation of the taxa is discussed below. TABLE -1 A brief synopsis of the dasslfication and number of species of the living reptiles In India Family No. of No. of genera species Crocodilia (Crocodiles) Testudines (Turtles and tortoises) Squamata
Animal Resources ofIndia Order Family No. of No. of genera species
Suborder Sauria (Lizards) Suborder Serpentes (Snakes) Agamidae Chameleonidae Scincidae Dibamidae Lacertidae Anguidae Vamnidae Typhlopidae Uropeltidae Xenopeltidae Boidae Acrochordidae Colubridae Dasypeltidae Elapidae Hydrophiidae Viperidae Crotalidae
Crocodiles
Gharial: Family Gavialidae. This is a monotypic family. The Gangetic gharial or gavial, Gavialis gangeticus inhabits the Ganga and its tributaries in the north and extends as far south as Mahanadi in Orissa. It is one of the most endangered reptiles in the world.
Crocodiles: Family Crocodylidae. The family is represented in India by two species namely the Muggar, Crocodylus palustris, and the Saltwater Crocodile, Crocodylus porusus. The mugger is widely distributed throughout the Indian subcontinent whereas the saltwater crocodile is widely distributed in southern Asia. In India, it is a rare species as it is confined to parts of the east coast of the mainland and to the Bay Islands.
Turtles and Tortoises
Sea turtles: Families Dcrmochelyidae and Cheloniidae. Five species of marine turtles are found in coastal waters of India. Of these, the Leatherback sea tutle, Dermochelys coriacea is the sole representative of the family Dermochelyidae and is a rare species. The remaining four species namely the Green turtle (Chelonia mydas), the Olive Ridley (Lepidochelys olivacea), the Hawksbill (Eretmochelys imbricata), and the Loggerhead (Caretta caretta) are contained in a single family, Cheloniidae. Barring the loggerhead turtles, all the other forms nest on our coasts. All the sea turtles are listed as species threatened with extinction and declared as protected species.
Freshwater turtles: Family Emydidae. Seventeen species of freshwater turtles classified in seven genera namely, Batagur, Hardella, Kachuga, Geoclemys. eyclemys, Heosemys, and Melanochelys occur in India. Most of the emydid turtles are aquatic or semiaquatic.
The mono typic genus Batagur represented by its type species, Batagur baska, is economically important for its flesh and eggs. It is found in the estuaries of the Sunderban and is a rare turtle. The Brahminy river turtle, Hardella thurgi inhabits the Ganga, Brahmaputra and Indus river systems. Six species of Kachuga occur in India and Burma. All these turtles are used for food and considerally exploited. The Spotted pond turtle, Geoclemys hamiltoni occurs in the Ganga and Indus river systems.
The Khasi hill tortoise, Cyclemys dentata and the Assam freshwater tortoise, Cyclemys mouhoti are Indo-Chinese representatives extending their range to the eastern India. The Kerala forest turtle, Heosemys silvatica is a rare species which has recently been collected since its original discovery in 1911. It is endemic to India. "The genus Melanochelys, which ranges from India to Japan and the Malayan archipelago, has five representatives in India. These are the three keeled tortoise, Melanochelys tricarinata, the snail-eating turtle, Melanochelys trijuga trijuga, the black-necked twtIe, Melanochelys trijuga coronata and Melanochelys trijuga indopeninsularis and Melanochelys trijuga thermalis. Of these, M. tricarinata, M. trijuga trijuga, and M. t. coronata are endemic to India.
Land tortoises: Family Testudinidae. There are four land tortoises in India, all placed in the genus Geochelone. The Indian starred tortoise, Geochelqne elegans occqrs throughout central and southern India and also extends to the east in Orissa and the west in Pakistan. The Burmese elongated tortoise, Geochelone elongata is an Indo-Chinese form occurring in northeastern India. The Burmese brown tortoise, Geochelone emys is a giant among the Asian land tortoises and is confined to the hills of eastern India and southeastern Asia. The Travancore tortoise, Geochelone travancorica is endemic to India. It is found mainly in the hills of southern Kerala and Coorg (Kamataka).
Flap-shelled turtles: Family Trionychidae. The flapshells or softshells include three genera; viz. Lissemys, Trionyx, and Chitra represented by five species. The Gangetic softshell, Trionyx gangeticus is the common twtIe of the Ganges, Indus and Mahanadi river systems. The Peninsular softshell, Trionyx leithi is a river turtle of the Gangetic system but is also found in the rivers of peninsular India. A little known but pretty trionychid is the Peacock softshell, Trionyx hurum which inhabits the lower reaches of the Ganga, Brahmaputra and Indus rivers. It is endemic to India. The genus Lissemys ~ncludes two forms, Lissemys punctata punctata and L. p. granosa. The Chitra softshell, Chitra indica is a monotypic species of the genus Chitra and is found in the Gangetic and Indus river systems of India, Nepal and Pakistan. Lizards
Geckos: Family Gekkonidae. Some 54 species contained under 14 genera namely, Eubleparis, Teratolepis, Stenodactylus, Cyrtodactylus, Cnemaspis, Calodactylodes, Dravidogecko, Hemidactylus, Hemiphyllodactyius, Gekko, Ptychozoon, Phelsuma, Gehyra, and Lophopolis are known. The Andaman Day Green Gecko, Phelsuma andamanensis is restricted to the Andamans. Another interesting gecko of Indo-Malayan origin is the Flying ge~ko, Ptychozoon kuhli which is restricted to the Nicobar Islands. The genus Cnemaspis, comprising about 11 species, is an assemblage of dwarfed forest geckos, e~demic to the hills of southern India. The Golden tree gecko, Calodactylodes sureus is a mono typic form and is another rare Indian gecko found in the Eastern Ghats. Another monotypic form found in the Western Ghats is the southern forest gecko, Dravidogeck anamallensis.
Agamids: Family Agamidae. The agamid lizards of India are known by 43 species in fourteen genera namely, Draco, Sitana, Otocryptis, Ptyctolaemus, Goniocephalus, Mictopholis, Oriocalotes, Japalura, Salea, Caloles, Psammophilus, Agama, Phrynocephalus. and Uromastix.
The genus Draco represents the Indo-Chinese element in the reptile fauna of India. It includes the two so-called "Flying dragons", Draco norvilli found in Assam and Draco dussumiani of South India. The Earless lizard, Otocryptis beddomii is found in the Western Ghats and is endemic to India The genus Salea comprises the hill species, Salea horsfieldi and Salea anamallayana both of which are endemic to India. Another genus encJemic to India is Psammophilus which includes two species of rock lizards found in the peninsular India. The Spiny-tailed lizard, Uromastix hardwickii of the arid tracts of northwestern India is• an endangered species as it is much sought after for its flesh and oil.
Chameleons: Family Chamaeleonidae. The Indian Chameleon, Chameleo zeylanicus is the sole representative of the family which is centered in Africa.
Skinks: Family Scincidae. The family of skioks is composed of 44 species distributed in 12 genera namely, Dasia, Sphenomorphus, Chalcides, Scincella, Riopa, Ablepharus, Ristella, Mabuya, Eumaces, Ophiomorus, Barkudia and Sepsophis. A great majority of the Indian skinks are migrants from Vietnam while a few are restricted to India. The genus Ristella comprising 4 species, is confmed to the moist jungles of the Western Ghats. The genera Barkudia and Sepsophis are represented by one species each, viz. Barkudia insularis &nd Sepsophis punctatus both of which are exceedingly mre and endemic to India.
Worm Lizards: Family Dibamidae. The glassy-scaled Indian Worm Lizard, Dibamus novae¬guineae is the only representative of the family in India. It is a rare species of Indo-Chinese origin and is found from the Nicobars to New Guinea.
Lacertids: Family Lacertidae. This family is an assemblage of typical lizards known by 8 species contained in 5 genera namely, Acanthodactylus, Cabrita, Eremias, Ophisops and Takydromus. The genus Cahrita comprises two species and is endemic to India. Another snake¬eyed lacertid endemic to India is Ophisops beddomei.
Glass-snake Lizards: Family Anguidae. The Burmese glass snake, 0 phisaurus gracilis is the sole representative of the family Anguidae in India. It is found in and around Darjiling (West Bengal) and the Khasi Hills, Meghalaya
Monitor Lizards: Family Varanidae. Four species of monitor lizards comprising the single genus Varanus are found in India They are the Common Indian monitor, Varanus bengalensis, the yellow monitor, Varanusflavescens, the Desert monitor, Varanus griseus, and the Water monitor, Varanus salva tor. Besides the Indian subcontinent, the monitor lizards are also found in Africa, Australia and the East Indies. These giant liz
