P. rajaei was officially described in a 2012 publication of the British Tarantula Society. It was discovered in 2009 when a villager brought a dead specimen to Ranil Nanayakkara, the co-founder of the Sri Lankan Biodiversity Education and Research organization, who was conducting an arachnid survey of Sri Lanka at the time.
The spider has a leg span of up to 20 centimetres (8 in), has vivid yellow and gray piping on the first and fourth legs with a pink abdominal band. It prefers to live in old-growth trees, but is considered rare due to deforestation in its war-torn habitat and has taken to living in old buildings. The venom of P. rajaei is not lethal to humans but can kill small rodents, birds, lizards and snakes. It is not yet known exactly how rare the newly discovered tarantula is, but there is some concern that habitat destruction is causing their number to dwindle.
The species was named for Michael Rajakumar Purajah, the local police inspector who guided the research team while they searched for living specimens.
- "Taxon details Poecilotheria rajaei Nanayakkara et al., 2012". World Spider Catalog. Natural History Museum Bern. Retrieved 29 February 2016.
- Nanayakkara, RP; Kirk, PJ; Dayananda, SK; Ganehiarachchi, GASM; Vishvanath, N; Kusuminda, TGT (2012). "A new species of tiger spider, genus Poecilotheria, from northern Sri Lanka". British Tarantula Society Journal. 28 (1): 6–15.
- "New Giant Tarantula Discovered in Sri Lanka". Wired.com. Retrieved 2013-04-04.
- "Spiders as big as your face discovered in Sri Lanka". Metro.co.uk. Retrieved 2013-04-04.