STUDIES ON THE ODONOTA FAUNA OF ANDAMAN AND NICOBAR ISLANDS

The archipelago of Andaman and Nicobar Islands is well known for its unique bio-genetic resources. These oceanic islands provide an ample scope of study of its Zoogeography. These islands are peaks of a submerged mountain hill range starting from Arakan Voma in Myanmar in the north to Sumatra in Indonesia in the south, between latitudes 6°45' and 13°41' N and longitudes 92°12' and 93°57' E. The island group comprises of more than 500 islands, islets and rocks with a total coastline of about 1962 Km. The area of these. islands covers 8,249 Km2•


INTRODUCTION
The archipelago of Andaman and Nicobar Islands is well known for its unique bio-genetic resources.These oceanic islands provide an ample scope of study of its Zoogeography.These islands are peaks of a submerged mountain hill range starting from Arakan Voma in Myanmar in the north to Sumatra in Indonesia in the south, between latitudes 6°45' and 13°41' N and longitudes 92°12' and 93°57' E. The island group comprises of more than 500 islands, islets and rocks with a total coastline of about 1962 Km.The area of these.islands covers 8,249 Km 2 •   The climate of these islands'is tropical with hot-humid condition~.The islands receive rainfall from both the south-west and north-east •l1\onsoons.The maximum precipitations is between april to December, the driest period being between January to M~uch.The temperature ranges from 22°C to 33°C and relative humidity usually ranging between 80% to 90% throughout the year.Despite the heavy rainfall, the islands possess very few freshwater stream, which are mostly present in Andaman and Great N icobar Islands.
These islands' are occupied by about 860/0 of the forest area, which support luxuriant growth of evergreen, semievergreen, moist deciduous, littoral and mangrove forests from water's edge to the hill-tops, depending on the topography and nature of soil.The vegetation is mainly composed of the Indo-Myanmar type in Andamans, while the Malayan elements are present in Nicobar group of Islands.
The first report on Odonata fauna of Andaman and Nicobar Islands was published by Selys (1853), who described new species of damselfly, Libel/ago lineata blanda from Great Nicobar Island.Subsequently, two more species, viz.Copera vittata serapica (Selys) and Epophthalmia vittata (Burmeister) were also reported by Selys in 1863 and 1871 respectively.'Fraser (1924) reported 9 species on the material of Dr. N. Annandale, who collected 17 specimens of odonates from these islands during the months of November and December, 1923.Later on all these species were included in the "Fauna of British India" by Fraser (1933,1934,1936).
After a long gap, Chhotani et al. (1983) studied the materi'al of Odonata present in the Z.S'!.HQ, Calcutta, collected by the various survey parties from Andaman and Nicobar Islands and • Central Regional Station.Zoological Survey of India, 424.New Adarsh Colony, Jabalpur -482 002.added 21 species/subspecies including the description of two species i.e.GOlnphidia ganeshi a~d Oligoaeschna andamani, which raised the total number of species and subspecies to 34 under 24 genera.Lahiri and Mitra (1993) added eight species new to the odonate fauna of these islands.Mitra (1995) worked on the old collection of Great Nicobar Island and added 8 species to the fauna of the Island.Since 1991, several surveys' to different parts of Andaman and Nicobar Islands were undertaken by the authors and staff of Andaman and N icobar Regional Station, Port Blair, Which resulted into the addition of eight species, of which seven species, viz.Pseudagrion microcephalum (Rambur), Gomphidia T-nigrum Selys, Gynacantha bayadera Selys, Cratilla lineata calverti Foerster, Lyriothemis cleis Brauer, Indothemis carnatica (Fabricius) and Zyxomma petiolatum Rambur are new records to the Andaman and Nicobar Islands; while one species, i.e.Cratilla metallica (Brauer) is new addition to the odonate fauna of India.A running key for the identification of known species of Andaman and Nicobar is provided.The paper also furnishes an uptodate list of Odonata fauna of these islands.The distribution of each species spread over group of Islands is also appended as Table I.  5. Pseudagrion pruinosum (Burmeister) 6. Pseudagrion williamsoni Fraser   7. Aciagrion pallidum Selys   8. Ischnura senegalensis (Rambur) 9. Agriocnemis femina oryzae (Lieftinck) 10.Agriocnemis pygmaea (Rambur)   Elsewhere: Throughout India, Sri Lanka, Myanmar and Malaysia.

Order
Remarks This is one of the common species in Indian subcontinent but rare in Andamans.Elsewhere : Throughout plains of India.

Ceriagrion olivaceum
Remarks: This species is recorded for the first time from Andaman & Nicobar Islands.The specimen examined is very tender and its anal appendages compressed.The abdominal marking on segment 2 and presence of three small spines on the superior appendages con finn the species identity.
Remarks: This species is included here on the basis of literature review.This is not a common species in Andaman.Elsewhere: Widely distributed in India, Nepal, China, Sri Lanka, Myanmar, Thailand, Malaysia, Indo-China and Taiwan.

Genus
Remarks : This is one of the commonest spec~es all over India and spairingly in South-east Asia.
Remark : This species is included here on the basis of literature review.(Fraser) 19.Libellago lineala andamanensis (Fraser) Remarks: The species is endemic to Andaman Islands, which is allied to Libel/ago lineata indica (Fraser) but differs in larger black markings on abdominal segments.-Abdomen very tum id at base, then abruptly narrowed and very slim and cylindrical to the end; wing broadly tipped With dark brown and without opalescent white spot in centre of hind wing .Elsewhere Throughout India, Myanmar, Sri Lanka, Thailand, Sumatra, Java, Borneo, Malaysia, Ryukus, Seychelles, Indo-China, Micronesia and Australia.

SUMMARY
The present paper deals with 58 species and subspecies of odonate fauna belonging to 38 genera and 11 families known from Andaman and Nicobar Islands.Of these, seven species are recorded for the first time from Andaman and N icobar Islands and one species is addition to odonate fauna of India.
Else"'here : India (Assam and West Bengal), Ryukyu Island, Borodino Island, China and Taiwan.Remarks: This is one of the commonest species in Andaman and Nicobar Island and for the first time recorded from Great N icobar Island.
Distribution in A. & 3. The nervure IRiii making an abrupt curve towards and beneath outer end of pterostigma; MA fusing with Riv + v well before posterior border of wing; Rspl.forked shortly after its origin, the posterior branch running parallel with Riv + v to posterior border of wing; superior anal appendages with apex prolonged and curled downwards abruptly .......... Anaciaeschna Selys -The nervure Ri i i without an abrupt curve towards and beneath the outer end of pterostigma; MA not fusing with Riv + v, but interrupted or forked at the same level; superior anal appendages not prolonged at the apex .... Peninsular India, Uttar Pradesh and West Bengal.
Distribution in A. & N. South Andaman.