Predicrostonyx is a genus of extinct rodent in the family Cricetidae. It contains only the species, Hopkins`s Lemming, Predicrostonyx hopkinsi, which is considered one of the earliest examples of collared lemmings. ... Found on http://en.wikipedia.org/wiki/Predicrostonyx
1) Extinct rodent 
Predicrostonyx is a genus of extinct rodent in the family Cricetidae. It contains only the species, Hopkins`s Lemming, Predicrostonyx hopkinsi, which is considered one of the earliest examples of collared lemmings. ...