Source: http://monsterhunter.wikia.com/wiki/Fanged_Beast

Fanged Beasts (Japanese 牙獣種 „Gajūshu“, also known as Pelagus and Primatius) monsters are beastly mammalian creatures that operate with only legs, and no wings. They are often much faster than other larger threats. The first Primatius monsters appeared in Monster Hunter 2. They were referred to as Primatius in earlier translations, but as of Unite are known as Pelagus. More of the Pelagus were added in MHP3, they are known as Fanged Beasts in the Japanese version, and in the English version of Monster Hunter 3 Ultimate.