'Ultimate Pokémon' Squirrel Evades the Eyes of Science

An illustration from 1898 shows the Zenkerella insignis.

They know it exists, thanks to eyewitness accounts and a handful of bodies found over time, but a squirrel in central Africa continues to elude biologists, who have yet to see one alive. Three new bodies, however, have at least given scientists a chance to sample its DNA for the first time.

The squirrel, Zenkerella insignis, a rodent with scales at the base of its tail, has been so successful at staying off the grid that only 14 of its specimens are curated in museums.

"Zenkerella could be seen as the ultimate Pokémon that scientists have still not been able to find or catch alive," said Erik Seiffert, lead author of a new study in the journal Peer J on the little-seen rodent, in a statement.

"After all," added the professor of cell and neurobiology at the University of Southern California, "it probably only shows up in the middle of the night, deep in the jungles of central Africa, and might spend most of its time way up in tall trees where it would be particularly hard to see."

The second of three new specimens of Zenkerella insignis was found by hunters near the village of Ureca on Bioko, an island off the west coast of Africa.

But genetic testing can tell scientists much about the critter, even if they can't spot one alive.

Cheek swabs taken from three recent specimens of the creature allowed Seiffert and his colleagues to compare Zenkerella's DNA against other rodent DNA sequences, to learn more about the mysterious animal's place in the taxonomic tree.

Having traditionally been lumped in with two other "scaly-tailed squirrels" in the Anomaluridae family, thanks to brain and jaw similarities, the researchers argue that Zenkerella actually belongs under its own, newly named family Zenkerellidae.

At issue is the ability to glide. The other two Anomaluridae squirrels -- Anomalurus and Idiurus -- have webbing between their legs and elbows, which allows them to glide between trees. But Zenkerella has no such webbing.

According to the researchers, grouping the three squirrels together, implied "that either the Zenkerella lineage lost its gliding adaptations, or that Anomalurus and Idiurus evolved theirs independently."

The scientists say their data shows that gliding only evolved once among the Anomaluridae, without subsequent loss of the ability, making Zenkerella a distant cousin to Anomalurus and Idiurus and worthy of a different family.

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