pygomelian
/ˌpʌɪɡə(ʊ)ˈmiːlɪən/Veterinary Med. and Medicine rare
noun
An animal (or person) exhibiting an abnormality of development in which one or two supernumerary limbs (more or less developed) are attached near or between the normal posterior limbs.
Origin
Late 19th century; earliest use found in William Bateson (1861–1926), biologist. From French pygomèle + -ian.