Hassianycteris is an extinct genus of Early Eocene (Ypresian) to Middle Eocene (Lutetian) bats from the Hassianycterididae with four or five known species: the type (H. messelensis), H. magna, and H. revilliodi, all found in the Messel pit, Germany,[1][2][3] H. kumari, found in the Cambay Shale Formation (Vastan Lignite Mine), India,[4] and the possible fifth species "H." joeli, found in the Kortijk Clay Formation, Belgium,[5] which may instead belong to Onychonycteridae.

[3] The Messel bats Palaeochiropteryx and Hassianycteris (alive roughly 48 million years ago) are the first fossil mammals whose colouration has been discovered: both were reddish-brown when alive.

[6][7]