Fossil- A remnant or trace of an organism of a past geologic age, such as a skeleton or leaf imprint, embedded and preserved in the earth's crust.
Mammalian- an animal of the class Mammalia; mammal.
Reptilian- belonging or pertaining to the Reptilia.

Scientists believe that certain animals could be related do to a resemblance to the ear bones. Scientists haven't quite figured out what it is but plan to figure it out.