This image, taken in 2002, about one mile deep near a huge underwater volcano near Monterey Bay, provided by NOAA shows this strange marine animal, thought to be a new species that has yet to be described or named. It is a type of mollusk, called nudibranch, that sheds its shell early in life. Scientists think there are millions of species, like this one, that have yet to be named or even discovered. – AP Photo/NOAA

WASHINGTON: Some 8.7 million different species exist on Earth, though a tiny amount of those have actually been discovered and catalogued, researchers said Tuesday.

The count, described by the open access journal PLoS Biology in which it is presented as “the most precise calculation ever offered,” replaces previous estimates that swung between three million and 100 million.

About 1.25 million species have been discovered and classified since Swedish scientist Carl Linnaeus came up in the mid-1700s with the taxonomy system still used today.

The 8.7 million figure is a projection based on a mathematical analysis of currently known species.

Around 86 per cent of land species and 91 per cent of creatures in the ocean have yet to be discovered, said the findings by scientists at Dalhousie University in Canada and the University of Hawaii.

“The question of how many species exist has intrigued scientists for centuries and the answer, coupled with research by others into species' distribution and abundance, is particularly important now because a host of human activities and influences are accelerating the rate of extinctions,” said lead author Camilo Mora of the University of Hawaii.

“Many species may vanish before we even know of their existence, of their unique niche and function in ecosystems, and of their potential contribution to improved human well-being.”

This undated image provided by seaphotos.com shows the face of a Histiophryne psychedelica, a highly atypical a psychedelic frogfish (Antennaridae) first described in 2009 from a handful of specimens photographed in Ambon, Indonesia in 2008. It has a vestigial, non-functional lure (illicium/esca) and probably traps its prey inside coral holes and crevices or within coral rubble. The unusual pattern is thought to mimic the appearance of several kinds of hermatypic coral, and while varying slightly from individual to individual, appears to remain unchanged throughout the life of each individual. – AP Photo/David Hall

The study estimated that there are 7.77 million species of animals, of which 953,434 have been described and catalogued, and 298,000 species of plants, with 215,644 of them described and catalogued so far.

Researchers also said there are likely 611,000 species of fungi, such as mold and mushrooms, of which 43,271 are known to science.

Some 36,400 species of protozoa, or single-cell organisms such as amoebas and 27,500 species of chromista, such as brown algae and water molds, were also included in the projected count.

“Humanity has committed itself to saving species from extinction, but until now we have had little real idea of even how many there are,” said co-author Boris Worm of Dalhousie University.

The Red List issued by the International Union for Conservation of Nature monitors 59,508 species, of which 19,625 are classified as threatened.