RESEARCH COMMUNICATIONS CURRENT SCIENCE, VOL. 92, NO. 2, 25 JANUARY 2007 213 *For correspondence. (e-mail: rkishna52@gmail.com) buffer and with viscosity between 10,000 and 30,000 cen- tipoise in pre-filled syringes was produced under license from the Drugs Control authorities and injected into knees of people suffering from osteoarthritis. The results are given in Table 6. It can be seen from Table 6 that the formulation had excellent rejuvenating effect on all the recipients. Moreover, none of the patients had any note- worthy inflammatory reaction. After the completion of the efficacy studies, more than 4500 sterile, pre-filled syringes were made available to more than 1500 patients suffering from osteoarthritis of the knee. The results of application have been excellent. Sodium hyaluronate of molecular weight between 1.0 and 1.3 MDa in the form of 1% solution in phosphate buffer, with a viscosity between 10,000 and 30,000 centi- poises behaves like a viscoelastic fluid. It shows excellent therapeutic effects on all recipients suffering from os- teoarthritis of the knee. More than 4500 pre-filled sy- ringes were made available to about 1500 patients from all over the country. 1. Watterson, J. R., Viscosupplementation: Therapeutic mechanisms and clinical potential in osteoarthritis of the knee. J. Am. Acad. Orthop. Surg., 2000, 8, 277���284. 2. Balazs, E. A. and Denlinger, J. L., Viscosupplementation: A new concept in the treatment of osteoarthritis. J. Rheumatol. (Suppl. 39), 1993, 20, 3���9. 3. Ghosh, P., Read, R., Numata, Y., Smith, S., Armstrong, S. and Wilson, D., The effects of intra-articular administration of hyalu- ronan in a model of osteoarthritis in sheep. II Cartilage composi- tion and proteoglycan metabolism. Semin. Arthritis Rheum. (Suppl. 1), 1993, 22, 6, 31���42. 4. Ghosh, P. and Guidolin, D., Potential mechanism of action of intra-articular hyaluronan therapy in osteoarthritis: Are the effects molecular weight dependent? Semin. Arthritis Rheum., 2002, 32, 10���37. 5. Ghosh, P., The role of hyaluronic acid (hyaluronan) in health and disease: interactions with cells, cartilage and components of syno- vial fluid. Clin. Exp. Rheumatol., 1994, 12, 75���82. 6. Forrester, J. V. and Wilkinson, P. C., Inhibition of leucocyte loco- motion by haluronic acid. J. Cell Sci., 1981, 8, 315���331. 7. Huskisson, E. C. and Donnelly, S., Hyaluronic acid in the treatment of osteoarthritis of the knee. Sodium hyaluronate in the treatment of osteoarthritis of the knee. Rheumatology, 1999, 38, 602���607. 8. Wright, J. M., Crockett, H. C. and Dowd, M., The role of visco- supplementation for osteoarthritis of the knee. Orthoped. Special Edn., 2001, 7, 15���18. 9. Puttick, M. P., Wade, J. P., Chalmers, A., Connell, D. G. and Rangno, K. K., Acute local reactions after intra-articular hylan for osteoarthritis of the knee. J. Rheumatol., 1995, 22, 1311���1314. 10. Henderson, E. B., Smith, E. C., Pegley, F. and Blake, D. R., Intra- articular injections of 750 kDa hyaluronan in the treatment of osteo- arthritis: a randomised single centre double blind placebo controlled trial of 91 patients demonstrating lack of efficacy. Ann. Rheum. Dis., 1994, 53, 529���534. 11. Goldberg, V. M. and Coutts, R. D., Pseudoseptic reactions to hylan viscosupplementation Diagnosis and treatment. Clin. Orthop., 2004, 419, 130���137. 12. Balazs, E. A., Leshchiner, A., Leshchiner, A., Larsen, N. and Band, P., Hylan preparation and method of recovery thereof from animal tissues. US Patent No: 5,099,013, 24 March 1992. 13. Balazs, E. A., Ultrapure hyaluronic acid and the use thereof. US Patent No: 4,141,973, 27 February 1979. 14. Swann, D. A., Kuo, J. and Pinsky, V., Steam-sterilizing solid hya- luronic acid. US Patent No: 5,621,093, 15 April 1997. 15. Colowick, S. P. and Kaplan, N., Methods Enzymol., 1972, 28, 134. Received 2 January 2006 revised accepted 22 August 2006 Extension of range of distribution of Nasikabatrachus sahyadrensis Biju & Bossuyt (Amphibia: Anura: Nasikabatrachidae) along Western Ghats, with some insights into its bionomics C. Radhakrishnan*, K. C. Gopi and Muhamed Jafer Palot Western Ghats Field Research Station, Zoological Survey of India, Calicut 673 002, India Nasikabatrachus sahyadrensis Biju & Bossuyt is obser- ved to occur in the forested habitats of the Nilgiri ranges north of Palakkad Gap, indicating its extension of range of distribution from the hitherto known limit south of the Palakkad Gap between 8 and 11��N lat, i.e. Anamalai and Cardamom Hills in the Western Ghats. The adult individual of N. sahyadrensis freshly uneart- hed from a scooping pit in the habitat was tested for its behavioural tendencies for burrowing in the field and feeding in the laboratory under captive conditions in a glass tank filled with damp soil and prey. Some aspects of bionomics of this fossorial frog focusing on its burrowing and underground foraging behaviours with reference to morphological and ethological char- acteristics of the taxon are presented here. Keywords: Bionomics, burrowing, foraging behaviour, Nasikabatrachus sahyadrensis, Palakkad Gap. BIJU and Bossuyt1 described the burrowing frog Nasika- batrachus sahyadrensis, a new amphibian species from India, veritably acknowledged by animal taxonomists and biogeographers all over the world as one of the rarest kinds of ���once in a century find���2. Molecular dating estimates and phylogenetic DNA analyses of the frog, recognized under a new family, indicate the new taxon���s relationship with frogs of the family Sooglossidae endemic to Sey-

RESEARCH COMMUNICATIONS CURRENT SCIENCE, VOL. 92, NO. 2, 25 JANUARY 2007 214 chelles, thereby suggesting its evolutionary origin 130 million years ago, even before the break-up of the ancient Gondwanaland mass. The discovery of N. sahyadrensis from India and its relationship with sooglossids in Sey- chelles have revived the concept of the prehistoric land bridge between Africa and India that might have been a dispersal corridor for animals between the two countries. Biju and Bossuyt1 collected the holotype of N. sahya- drensis from a degraded forest near a cardamom plantation at Kattappana (type locality, 09��45���N, 77��05���E, altitude approximately 900 m asl), Idukki District, Kerala, Western Ghats, India. Dutta et al.3 considered three specimens of ���pignose frog��� as similar to N. sahyadrensis, and there- fore placed it under the family Nasikabatrachidae. Two specimens (one male and one female: SVL 52.8 and 89. 9 mm respectively) were collected from a rainforest fragment, at Sankaran Kudi (10��14���46���N, 76��55���55���E) in the Anamalais, Tamil Nadu, and the third one (a gravid female, SVL 78.3 mm) from Murikkassery (near Kotha- mangalam), Ernakulam District. They have also examined additional specimens: one male (SVL 67.0 mm) collected from the Manimala River at Erumely, Kottayam District, Kerala, one immature male (45.0 mm) from Najayappilli village, near Thattekkad Bird Sanctuary, Ernakulam Dis- trict, and one mature male (SVL not known) from Indira Gandhi Wildlife Sanctuary, Pollachi, Tamil Nadu. Dutta et al.3 have also studied four tadpoles, supposedly of the fossorial frog taxon, collected from a fast-flowing stream in a coffee estate at Manamboli (10��22���59���N, 76��55���23���E) in the Anamalais. Based on the above-mentioned collec- tion data, Dutta et al.3 presumed the distribution limits of the frog taxon as being the forested habitats in the south- ern Western Ghats, falling within the range between 8�� and 11��N lat. The presumed range evidently falls just south of the Palakkad Gap of the Western Ghats. On 3 August 2004, a specimen collector brought to us one plump specimen of a frog (SVL 57.2 mm), reportedly obtained while digging out pits in a cleared site of a rubber plantation at Karuvarakundu, Malappuram District, Kerala. The frog, which was in its burrowed habitude, about 3 ft beneath the ground surface, got exposed while scooping the pit. The next year, in a faunal exploration trip to this area, we could make a fortuitous collection of a second specimen (SVL 87.5 mm) of the species on 6 July 2005 from the same locality, again during soil-digging. The exact collection site falls within a plantation land, viz. Kundode Estate (lat. 11��06.4���N, long. 76��64���E, elevation approximately 500 m asl). Notably, it was during the monsoon period that both the specimens were collected. Both the specimens (ZSI/CLT-V/A: 575 and 576) were identified as N. sahyadrensis based on the following salient characteristics. Body plump and relatively large in size skin smooth but thick, and colouration dorsally black and ventrally dark grey. Head small, relatively short to body length, and sub-conical snout tapered to a knob-like white protuberance a pair of nostrils, one each on either side of the snout���protuberance at its base eyes small, upper eye- lid prominent, lower eyelid merely an integumentary fold, iris black with a rounded pupil (horizontal pupil as men- tioned in the original description1), eye-diameter less than the distance between anterior eye-margin and the nostril, or inter-orbital distance tympanum absent mouth ventral, vomerine teeth absent, tongue small and rounded in front. Fore limbs short, palm hard, with fingers hardly/rudi- mentarily webbed, and tips rounded without discs hind limbs small, tibia short, toes three-fourth webbed and rounded at the tips without discs, and with a large, elon- gated, shovel-like inner metatarsal tubercle. The characteristics of the specimens available with us resembled the described features of N. sahyadrensis Biju & Bossuyt1 and the fossorial frog taxon of Dutta et al.3 thereby indicating the identity of the latter with none other than the species N. sahyadrensis itself. Following the collection of the specimen, we made some key observations on the bionomics of this amphibian species evidenced from its habitat site and the surround- ing environs. The collection site formed an area of disturbed/altered forest habitat on the gentle slope of a hill. The altered habitat comprised a mixed vegetation of plantation crops of cocoa and coffee on the hilltops, and rubber plantation on the slopes. A stream almost in a depleted phase was also observed in the area. The soil was mostly red, with a texture of top-layered forest loam on the surface and red soil underneath. The eco-habitat area veritably forms an integral part of the peripheral hilly-habitat environs that adjoin the Silent Valley National Park. The plantation workers who enabled us to collect the specimen are knowledgeable about the existence of the burrowing frog N. sahyadrensis in the habitat mentioned above. They find this uncommon frog while cutting trenches in the plot during the monsoon period (June to October) and are aware of some behavioural peculiarities. According to them, live individuals are sparingly visible in the vicinity of the water paths/pools, at times found in pairs clasping each other, or buoying up in the side pools of the swelling streams, especially during the beginning of the monsoon season. We made an attempt to observe the burrowing habit of the frog in the field by leaving it on a heap of loose soil. The lone robust frog freshly collected from the habitat was released at four different spots of varying surface hardness on the ground to observe some possible clues on its bionomics and behaviour. When left in the damp red- loam soil, the frog instinctively started to dig down and burrow itself beneath the loose soil and disappeared in the heap within 3���5 min. On hard-ground surface it made a vigorous attempt to burrow down, but not gaining enough progress, moved away from the spot. It looked uncomfortable to burrow down a ground with a thick mat of cluster weeds. When kept on pebbled���gravel-strewn