Polyonax alticornis Dinosaur: Polyonax alticornis Period Details Status: S > Triceratops alticornis Author: Cope Year: 1889 Distribution Classification Sources References: E. D. Cope. (1889). The age of the Denver Formation. ________________________ Please Support the Dinosaur Database: Facebook Twitter LinkedIn Tumblr VKontakte Odnoklassniki Pocket Skype Messenger Messenger WhatsApp Telegram Viber Line Share via Email