Scientists busily cataloguing world's millions of unidentified inhabitants offer top 10 new finds.

A "ghost snail", a tiny fringed fairyfly named Tinkerbell and a pale yellow sea anemone that is at home under a glacier are on an international list of the 10 top species discovered last year.

Also featured were a see-through shrimp, a hard-to-spot gecko, a not-so-hard-to-spot 12m tree, and a microbial species found in "clean rooms" where spacecraft were being assembled.

Now named Tersicoccus phoenicis, the pesky, steriliser-resistant species could have been an inter-planetary stowaway, hitching a ride into space with humans none the wiser.

The list was compiled by an international committee of taxonomists and related experts, who sifted through about 18,000 new species named during the previous year to find the top 10.

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Although no New Zealand finds feature on the list, it contains bizarre discoveries made in Australia and Antarctica.

Established in 2008 by the International Institute for Species Exploration in New York, the list calls attention to discoveries that are made even as species are becoming extinct faster than they are being identified.

"The majority of people are unaware of the dimensions of the biodiversity crisis," said the institute's founding director, Dr Quentin Wheeler.

Scientists believe 10 million species await discovery, five times the number known to science.

"The top 10 is designed to bring attention to the unsung heroes addressing the biodiversity crisis by working to complete an inventory of Earth's plants, animals and microbes," Dr Wheeler said.

"Each year a small, dedicated community of taxonomists and curators substantively improve our understanding of the diversity of life and the wondrous ways in which species have adapted for survival."

The chairman of the institute's selection committee, Dr Antonio Valdecasas, said one of the most inspiring facts about the list was that not all of the "big" species were known or documented.

"One species of mammal and one tree species confirm that the species waiting to be discovered are not only on the microscopic scale," he said.

Dr Valdecasas pointed to two of the species, the shrimp, Liropus minusculus, with its "phantasmagoric appearance", and the gecko, which bore a "disturbing likeness to some imaginary monster".

"Beautiful beasts, I would rather say," he said.

View: The top 10 new species