As mentioned earlier, the genus Poecilotheria of ‘tiger spiders’, to which the Gooty Sapphire belongs, is endemic to South India and Sri Lanka. They have become very popular among spider lovers for their bright colours and hardy nature. But there is more to them than just spots and patterns. One species, the Rameshwaram Ornamental (Poecilotheria hanumavilasumica) has provided evidence of South India and Sri Lanka being connected to each other by a land bridge in the Pleistocene.

The species is named after the temple town of Rameshwaram in Tamil Nadu’s Ramanathapuram District (which is separated from Sri Lanka’s Mannar District by the Palk Strait). Rameshwaram is located on Pamban Island. Both the island, and the town are of great religious significance to Hindus. It is believed that Rama, the exiled crown prince of Kosala (and hero of the Hindu epic Ramayana) came to Pamban Island in search of his wife (Sita, who had been abducted by Ravana, the king of Lanka, identified with present-day Sri Lanka).

In the epic, Rama and his allies, the Vanaras (a race of ape-like beings) found out that Sita was held in Ravana’s palace across the sea. In order to reach Lanka, they began constructing a bridge spanning the Palk Strait. This bridge of legend is known as the Ramasetu. Devout Hindus believe that remains of that ancient bridge lie under the sea, with some parts exposed as the sand banks, shoals, spits and coral reefs that make up Adam’s Bridge between India and Sri Lanka. There has been a whole lot of controversy surrounding the origins of the submerged land bridge.

Keeping that controversy aside, one can say, based on scientific evidence, that the two landmasses were indeed connected. By a naturally formed causeway between the two islands – Pamban (Tamil Nadu) and  Mannar (Sri Lanka). And with the formation of this causeway, there was an exchange of flora and fauna between them. No wonder then that there are some species which are endemic to South India and Sri Lanka. One example is the Rameshwaram Ornamental.

This Tarantula species was discovered in 2004 by Andrew Smith in a sacred grove attached to the Hanumavilasum Temple of Pamban Island. It was believed that it was restricted to Tamil Nadu’s Ramanathapuram District. However, in the year 2012, a group of researchers from Sri Lanka’s University of Kelaniya found Poecilotheria hanumavilasumica specimens on the island of Mannar, right across the Palk Strait, on its eastern flank. The distribution of the sixteen or so species of the genus Poecilotheria is now considered to be evidence of biotic exchange between India and Sri Lanka. Unfortunately, the spider that provided proof for the existence of a natural causeway between the two might very well disappear on account of rapid habitat loss.

Image Attribution: The image above, sourced from Wikimedia Commons, shows a photograph of the Rameshwaram Ornamental. It was taken from the ‘Critically Endangered Animal Species of India (2011)’.

Reference: