DNA has been sampled from a "living fossil" jungle squirrel dubbed "the ultimate Pokemon" because no scientist has ever observed one of the creatures alive.

The super-elusive scaly tailed squirrel, Zenkerella, lives in the forests of central and west Africa and has hardly evolved in the past 49 million years.

To date only dead animals have been studied, although the rodents are occasionally caught by native hunters who describe the meat as "not desirable".

Until recently just 11 Zenkerella specimens were preserved in museums around the world. Now three newly dead squirrels have come into the possession of scientists, allowing them to study the animal's fresh DNA for the first time.

Samples taken from cheek swabs show the creature is a distant cousin of "flying squirrels" that glide between forest trees with the help of skin stretched between their legs and elbows.

Zenkerella cannot glide, but like its cousins it has a set of scales on the bottom of its tail that may assist tree climbing.

Hunters caught the three new specimens in ground snares near the southern tip of Bioko Island off the west coast of Africa.

Lead researcher Professor Erik Seiffert, from the University of Southern California, said: "Zenkerella could be seen as the ultimate Pokemon that scientists have still not been able to find or catch alive."

Villagers on Bioko Island claim to catch the squirrels in forest floor traps once or twice a year. The rodent reportedly only comes out at night, sleeping in tree hollows during the day.

Of the estimated 5,400 known mammal species alive today, only Zenkerella and two others - the monito del monte, a mouse-like South American marsupial, and the pen-tailed tree shrew - have been awarded the title "living fossil".

All three closely resemble ancestors that lived in the early part of the Eocene epoch 49 million years ago.

Prof Seiffert added: "It's an amazing story of survival. We are only just starting to work on basic descriptions of Zenkerella's anatomy. It's fun to think that there might be other elusive mammalian species out there, deep in the rainforests of central Africa that will be new to science."

Scientists still know almost nothing about the rodent's lifestyle and diet.

Because the squirrel is thought to be distributed over a wide geographical region, it has been placed in the "least concern" category by the International Union for Conservation of Nature (IUCN) which monitors threatened species.

But study co-author Dr Drew Cronin, from Drexel University in Philadelphia, said: "This rating belies the fact that threats such as habitat loss and degradation are intense and widespread.

"Zenkerella may be under greater threat. The more information and visibility for the species we can generate, the more likely we are to facilitate the research and conservation attention a unique species like Zenkerella requires."

The research is reported in the journal PeerJ.