Aye-aye

According to The I-Spyder Book of Earth Creatures, the aye-aye — formally known as Daubentonia madagascariensis — was a type of lemur. It dwelt in forests and was mostly active at night. It had "black fur with white around its eyes and nose". Distinctive features of the mammal were its long middle fingers. These made digging out insects, its preferred food, more convenient. Its tail was one-and-a-half the length of its body, meaning that its total length was about 75cm

It was last seen on Earth in 2042 and died out because its habitat was destroyed.

The aye-aye had an I-Spyder point value of between 500 and 900. (NSA: The Last Dodo)

Behind the scenes
As with some other animals in The Last Dodo, there was a discrepancy between the point value given on the individual animal's page (500), and the amount Martha Jones was said to have received for actually spotting one (900).