Ba a samun kalmar "Prototheria" a cikin ƙamus na Turanci gama gari, amma kalma ce da ake amfani da ita a ilimin dabbobi don komawa ga rukunin dabbobi masu shayarwa waɗanda suka haɗa da tsarin rayuwa ɗaya kawai: Monotremata. Monotremes dabbobi masu shayarwa ne masu kwai, irin su platypus da echidnas, waɗanda ake samu a Ostiraliya da New Guinea. Ana kiran su "Prototheria" saboda ana ganin su ne na farko ko kakanni idan aka kwatanta da sauran nau'o'i biyu na dabbobi masu shayarwa: Theria (marsupials da placentals) da kuma Metatheria (marsupials kawai).