Pachydermata

For the recording studio, see Pachyderm Studio The Pachydermata (meaning "thick skin") is an obsolete order of mammals described by Georges Cuvier and at one time recognised by many systematists. Because it is polyphyletic, the order Pachydermata is no longer in use, but it is important in the history of systematics. Although it is often described as an artificial grouping of unrelated mammals, it was recognised as a grade of hooved mammals to the exception of other Ungulates by zoologists such as Charles Darwin, and anatomical characters do support the affinities of "Pachyderm" mammals to each other and to other Ungulates.
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(n. pl.)
A group of hoofed mammals distinguished for the thickness of their skins, including the elephant, hippopotamus, rhinoceros, tapir, horse, and hog. It is now considered an artificial group.