The caudofemoralis (from the latin cauda, tail and femur, thighbone) is a muscle found in the pelvic limb of mostly all animals possessing a tail, since it is a synapomorphy appeared on the Archosauria clade. It is thus found in felids (cats) and Mustela ('Weasels'), but also on crocodiles and birds. [ http://en.wikipedia.org/wiki/Caudofemoralis ]