‘Weli ka­tussa’ species unique to Sri Lanka

Sunday Times (Sri Lanka) - - NEWS - By Malaka Ro­drigo

Three young re­searchers have determined that Sri Lanka has its own species of fan-throated lizards – crea­tures that puff out an ex­tra­or­di­nary frill around their throats to warn off in­trud­ers – and that in fact the is­land has two dis­tinct va­ri­eties.

Un­til now it had been as­sumed that the fan-throated lizards found in Sri Lanka were the same as in In­dia.

Re­searchers Tha­sun Amaras­inghe, Sameera Karunarathna and Mad­hava Bote­jue stud­ied lizard spec­i­mens in the Cal­cutta and Chen­nai mu­se­ums and re­alised the Sri Lankan lizards were dif­fer­ent.

They widened their re­search to fan­throated lizard spec­i­mens at other for­eign mu­se­ums and con­firmed their the­ory, also find­ing that Sri Lanka has two species of this lizard: one found in the south-eastern coastal belt from Bun­dala to Ku­mana and an­other in the north­west, north of Put­ta­lam.

The two species were named Si­tana de­vakai and Si­tana bahiri to hon­our lead­ing bi­ol­o­gists Pro­fes­sor De­vaka Weer­akoon and Pro­fes­sor Mo­hammed Bahir.

“Prof. Weer­akoon was one of the first sci­en­tists to ini­ti­ate re­search on the bio­di­ver­sity of the north of Sri Lanka af­ter the re­stric­tions of the war ended so we named the lizard found in the north, Si­tana de­vakai,” Sameera Karunarathna said.

The team also wanted to hon­our Pro­fes­sor Mo­hammed Bahir for his ex­ten­sive re- search that es­tab­lished fresh­wa­ter crabs as the big­gest en­demic group in the coun­try. Since he came from the south­ern part of the is­land the fan-throated lizard found in the south was named Si­tana bahiri.

The fan-throated lizard, just 5cm long, mostly in­hab­its coastal ar­eas in­clud­ing sand dunes, hence its Sinhala name weli ka­tussa (sand lizard). Its hind legs have four toes un­like other lizards that have five toes. The re­searchers say this adap­ta­tion helps them to live in arid ar­eas where tem­per­a­tures are high and to move about ef­fi­ciently on sand.

The most in­ter­est­ing fea­ture of the species is the pouch on the throat of male lizards. When a ter­ri­tory guard­ing lizard spots an in­truder, it quickly ad­vances on the tres­passer and os­cil­lates this large, coloured pouch in a dis­play of threat. The frill found on Si. de­vakai is pink and blue while S. bahiri is less colour­ful.

The find­ings, by Mr. Karunaratna, Mr. Amaras­inghe, Ms Bote­jue and two col­leagues, Ivan Ine­ich and Pa­trick Camp­bell were pub­lished in the pres­ti­gious jour­nal Zootaxa ear­lier this month.

Last year, Mr. Karunaratna and Mr. Amaras­inghe took the lead in find­ing two other en­demic lizards, Calotes pethiyago­dai and Calotes man­a­mendrai (both from the Knuck­les for­est) named af­ter Rohan Pethiyagoda and Kelum Mana­men­dra-Arachchi who con­trib­uted to­wards the coun­try’s bio­di­versi- ty.

Sri Lanka is home to 21 species of lizards, 19 of them en­demic to the coun­try.

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