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Micrixalus fuscus (Anura: Ranidae) in Sharavathi River basin, Karnataka.

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Key words : Western Ghats, Sharavathi River Basin, amphibians, Micrixalus fuscus, range extension.

Micrixalus fuscus (Boulenger, 1882) is endemic to the Western Ghats (Chanda, 2002). Inger et al., (1984) recorded this species from Ponmudi hill range in Kerala, (955N and 7705E), whereas Vasudevan et al., (2001) observed them in Kalakkad-Mundanthurai Tiger Reserve, Tamil Nadu (825 853N and 7710 7735E).
Eight individuals of M. fuscus are recorded from Niluvase (134418N; 750630E;, and 692 m above msl) during ecological status assessment studies at Sharavathi River Basin on 6 November 2003. This species is found in the small rocky crevices amidst the flowing perennial streamlet covered with leaf litter in evergreen forest (Water depth: 78.3310.41 mm; water temperature: 22C; air temperature: 23C). It was observed to jump quickly from one rocky surface to other on disturbance, and hid in the crevices. The vegetation includes Mastixia arborea, Ventilago madraspatana, Aglaia sp. and Agrostistachys indica. Specimen has been deposited at National Zoological Collections of Zoological Survey of India, Kolkata (Reg. No. A9865)
Micrixalus fuscus (Figure 1) is a small, brown torrent frog (Snout vent length: 19.342.3 mm). Finger and toe tips are dilated into small discs. Webbing in foot is more than . Distinct features of this species are tibio-tarsal articulation reaching between eye and snout, indistinct tympanum and strongly overlapping hindlimbs (when folded at right angles to body).
The specimens are dark reddish brown on entire dorsum. Blackish inverted V on the mid-dorsum and also between eyes is observed in two specimens. Dorsolateral fold is with dark brown or with white dots. Lateral band is black and extends up to groin. Limbs are cross-barred. Brown reticulation is notices on the ventral side up to the abdomen and a light white strip from anus to knee joint.
Other species found in the region during the field survey are Nyctibatrachus major, Indirana semipalmatus, Euphlyctis cyanophlyctis, Sphaerotheca rufescens as well as species of unidentified Philautus and Sylvirana.
The record of M. fuscus from Sharavathi River Basin is the first record from Karnataka with an extended range of 13-14 N in the Western Ghats, as there was no record from Karnataka.

Acknowledgement

We acknowledge the financial support from the Ministry of Environment and Forests, Government of India and Karnataka Power Corporation Limited, Bangalore. We are grateful to M.S. Ravichandran, ZSI, Kolkata for his cooperation in species identification and Sanjeev Kumar Jha for proof reading the manuscript. We thank Divakar K. Mesta, Vishnu D. Mukri and H. Lakshminarayana for timely help in the field.

References

CHANDA, S.K. (2002): Hand book Indian Amphibians. Zoological Survey of India. Kolkata, pp. 57-58.

INGER, R.F., H.B. SHAFFER, M. KOSHY & R. BAKDE. (1984): a report on a collection of amphibians and reptiles from Ponmudi, Kerala, south India. J. Bombay nat. Hist. Soc. 81(2):406-427.

VASUDEVAN, K., A. KUMAR & R. CHELLAM. (2001): Structure and composition of rainforest floor amphibian communities in Kalakkad-Mundanthurai Tiger Reserve. Curr. Sci. 80(3): 406-412.

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