Consider the names of capitals of two US states together amounting to precisely 13 letters.

Rearrange these thirteen letters to constitute the names of two creatures. One of the creatures is a prehistoric animal found in the plains and the other is a present-day animal also found in the plains.
Spaces do not count as letters in city names such as "Santa Fe" or, "Des Moines".

*** Adapted from a problem appearing in NPR's "Sunday Puzzle" in 2005.