New Tardigrade Discovered: Mystery Eight-Legged Micro-Animal Found Lurking in Parking Lot

Updated | Scientists have identified a new species of tardigrade after it was discovered in a Japanese parking lot. The bizarre little creatures are distinguished by their bulging legs and the string-like filaments that grow from their eggs.

The new species is described in a research paper published Wednesday in PLoS One by Daniel Stec from the Jagiellonian University, Poland, and colleagues.

Short, plump, eight-legged micro-animals

An artist's impression of a tardigrade. Flickr/WIDOMIRAMA

Tardigrades are short, plump, eight-legged micro-animals measuring around 0.02 inches long. Sometimes called water bears or moss piglets, the critters pop up everywhere from the deep sea to rainforests. Fossilised tardigrades date back more than 500 million years.

Famed for their resilience, some species can survive extreme radiation, air deprivation and even the vacuum of space in a state of dormancy called "cryptobiosis."

"These amazing capabilities rely on DNA repairing mechanisms," Paulo Fontoura, a biologist and tardigrade expert from the University of Porto, Portugal, told Newsweek. "In the future, the knowledge obtained by the study of those complex mechanisms [could] have interesting consequences for cell and tissue preservation."

This latest addition to the tardigrade family—which has some 1,200 species—was discovered lurking in a clump of moss. Scientists took 10 individuals back to the lab and bred them to increase their sample.

Eggs and Legs

3_1_Targrada eggs
Elongated teeth form filaments on the new species' eggs. Stec et al (2018)

The team looked at the puffy little creatures under the microscope and analysed their DNA to confirm they were a new species: Macrobiotus shonaicus.

Most similar to certain members of the M. hufelandi group of the tardigrade family, M. shonaicus has a bulging layer on the internal surface of some of its legs, and thin fibers like tentacles that grow from its eggs. The eggs' solid surface puts the creatures in the persimilis subgroup of the hufelandi complex.

These elongated strings are similar to those found in two other species described since 2015—M. paulinae from Kenya and M. polypiformis from Ecuador. This helped the researchers understand where the newest members fit into the taxonomical tree.

A dorsal view of the new species. Stec D, Arakawa K, Michalczyk (2018) PLoS ONE

The new identification brings the number of known tardigrade species in Japan from 167 to 168. Around 20 new species are discovered every year, the authors write. So if you want to track down some tardigrades yourself, they shouldn't be lurking too far away.

According to Michael Shaw, tardigrade enthusiast and author, you may find the critters in moist clumps of moss or lichen on the trees and bricks of your neighborhood. Just scrape the moss into a petri dish, add water and wait overnight. The next day, you might be able to spot a tardigrade in the dish with a good amateur microscope. Shaw's article is available here and archived here.

This article has been updated to include comment from Paulo Fontoura and more information about M. shonaicus eggs.