New York, Sep 27 (IANS): Researchers have discovered 15 new species of "smiley-faced" spiders -- and named them, among others, after former US President Barack Obama and former presidential candidate and US Senator from Vermont Bernie Sanders.

Discovered in the Caribbean, the new species belong to a family of "smiley-faced" spiders called so due to a smiley face pattern on their abdomens.

Each new species of "smiley face" spiders has its own unique "smile", the researchers said.

Despite having profuse variation in its distinct colour patterns, it was, until recently, thought to be one species with extensive variation.

However, this molecular study of "smiley-faced" spiders has revealed that there are many more species within the genus, of which 15 are described in the paper published in the Zoological Journal of the Linnean Society.

Until now, the beautiful, yellow, smiley-faced spiders in the genus Spintharus has been thought to have one widespread species "from northern North America down to northern Brazil," said lead researcher Ingi Agnarsson, Professor of Biology at University of Vermont in the US.

For the study, the researchers collected specimens from Cuba, the Dominican Republic, Puerto Rico, Jamaica, the Lesser Antilles, Florida, South Carolina, Costa Rica, Mexico, and Colombia.

One of the newly discovered species is named Spintharus barackobamai to honour "the dignity, humanitarianism, statesmanship, and respect" they considered Obama to have brought to the Oval Office.

Another is named S. berniesandersi to honour a politician the paper characterised as "a tireless fighter for human rights and equality, and environmentally aware social democracy".

The new species were also named, among others, after Michelle Obama, actor Leonardo DiCaprio, and naturalist David Attenborough.