The Catalogue of Life is more current, it was updated Dec. 2015 and shows:
Echinopsis eyriesii Pfeiff. & Otto Species synonym for Echinopsis oxygona (Link) Zucc. ex Pfeiff.
I just went to the Plant List and it shows the latest date as March, 2012. One is listed as Accepted while others are shown as Synonyms:
http://www.theplantlist.org/tp...
I strictly use The Catalogue of Life because it always seems the most current.