Apterix

Apterix are a species of large, flightless birds native to the Mobian Prairie. Their meat is a growing market in Metropolis Zone and certain ranchers, notably Rooster and Boss Krouch, rear them specifically to sell them in Metropolis. Boss Krouch was once the sole supplier of Apterix meat, until Rooster came along.

They are particularly dangerous in a stampede because of their large size, and ranchers usually herd them from the air while riding pterodactyls.

Boss Krouch was able to synthesise a chemical compound that imitated the scent of the Apterix's most feared predator, but a hundred times more potent. He planned to use the compound to cause a stampede that would crush his rival, Rooster, but his plan was thwarted by Knuckles the Echidna and the Sheriff or Backwater City. Krouch was killed when he accidentally dropped the vial of the compound, and was caught in the stampede himself.

Trivia
The word Apterix appears to be used as both singular and plural, although the term Apterixes was used in issue 90.

When asked how he came up with the name Apterix, writer Nigel Kitching claimed that "I don't know where Apterix came from any more. I guess it just sounded like a dinosaur name to me. I'm pretty sure there is a flying dinosaur with a name similar to this but much longer." He was presumably referring to Archaeopteryx. (Note that, both Kitching and the questioner appeared to believe that Apterix was the name of the species of pterodactyl from the same story, rather than the flightless birds.)