The giant tarantula is as big as a human face.
Its legs, which have unique daffodil-yellow markings, span a massive 20cm (eight inches). The arachnid also has a distinctive pink band around its body.
The new species was found in the war-torn north of the South Asian country by scientists from Sri Lanka's Biodiversity Education and Research (BER) organisation.
It has been named Poecilotheria rajaei, in recognition of a senior police officer called Michael Rajakumar Purajah who guided the research team through a hazardous jungle overrun by civil unrest in order to seek out the spider.
