Sunday, June 9, 2019

Mihintale Red Narrow-mouthed Frog (Microhyla mihintalei)

English: Mihintale Red Narrow-mouthed Frog
Sinhala: මිහින්තලය රතු මුව පටු මැඩියා [Mihinthalaya rathu muwa-patu madiya]
Binomial: Microhyla mihintalei

Mihintale Red Narrow-mouthed Frog(Microhyla mihintalei) is an endemic frog and it was described recently (2016) with the help of specimens collected from dry zone of Sri Lanka including Mihinthale. The species was named after Mihintale which is one of the world’s earliest documented sanctuaries. It is also known as the place where King Dewanampiya Tissa met Mihindu thero who came from India in 246 BC.
But the ancestors of Microhyla mihintalei have found their way to Sri Lankan lowlands from India few million years ago via the land bridge created between Sri Lanka and India which was caused by earlier ice ages followed by excessive ice deposits in poles. But later, rise in the sea level caused land mass between India and Sri Lanka to disappear by creating an oceanic barrier and that resulted closing the land connection between two lands.
In India, Still lives a frog named Microhyla rubra, who is considered to be a descendent of the common ancestor of Microhyla mihintalei. As a result of thousands of years of separation due to the oceanic barrier between two land masses, Sri Lankan population of this common frog has been evolved as the new species we call, Microhyla mihintalei.
Studies have suggested significant genetic distance, morphology and differences in vocalization to distinguish Microhyla mihintalei from its common Indian ancestral species, Microhyla rubra.

Reference:
Meegaskumbura, Madhava; Biju, S. D.; Karunarathna, Nuwan; Senevirathne, Gayani; Garg, Sonali; Wijayathilaka, Nayana (2016). "A new species of Microhyla (Anura: Microhylidae) from Sri Lanka: an integrative taxonomic approach". Zootaxa. 4066 (3): 331–342. doi:10.11646/zootaxa.4066.3.9

Sunday, May 26, 2019

Rough-horn lizard(Ceratophora aspera)

English: Rough-horn lizard
Sinhala:රළු අංකටුස්සා[Ralu Ankatussa]
Binomial: Ceratophora aspera

Ceratophora aspera, an edemic horn bearing lizard was first described by Albert Günther in 1864.Several theories have been suggested to describe the evolutionary purpose of the horn of these agamid lizards.One such hypothesis suggests that it is used for the purpose of communication within the species. Also it is said that more larger and prominent horns in males are used in attracting females for reproduction. Another theory describes that rough, brown colored horn like structure has provided an evolutionary advantage by providing a form of camouflage by letting them to blend with the leaf litter filled environment. Studies carried out using mitochondrial DNA reveals that the diversification of C. aspera has been taken place from its common ancestor about 12.6 million years ago in the Miocene(Schulte et al. 2002).


Reference:
Schulte, James A, J.Robert Macey, Rohan Pethiyagoda, and Allan Larson 2002 Rostral Horn Evolution among Agamid Lizards of the Genus Ceratophora Endemic to Sri Lanka. Molecular Phylogenetics and Evolution 22(1): 111–117.