 "Oculudentavis" is even smaller than "Anchiornis", but it is uncertain if it is in fact an (avialan) dinosaur.With a mass of approximately and a length of 5 centimetres (2.0 in), the bee hummingbird ("Mellisuga helenae") is the smallest bird species, the smallest warm-blooded vertebrate, and smallest known dinosaur.Called the "zunzún" in its native habitat on Cuba, it is lighter than a Canadian or U.S. penny.