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.
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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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