1) Transitional fossil 
Darwinius is a genus within the infraorder Adapiformes, a group of basal strepsirrhine primates from the Eocene epoch. Its only known species is Darwinius masillae, approximately 47 million years ago (Lutetian stage) based on dating of the fossil site. The only known fossil, called Ida, was discovered in 1983 at the Messel pit, a disused quarry ne...