Tubulidentata is the only mammalian order that contains a single living species, the aardvark, Orycteropus afer. It has been called a ‘living fossil’ because it exhibits primitive anatomical characters that have shown little or no morphological change over about 20 million years. The ordinal name Tubulidentata is derived from tiny dentinal tubules found in the chewing surfaces of its teeth. Tubulidentata probably originated in Africa and has its roots in a group of extinct archaic ungulates known as the condylarths.