This name is a synonym of Dioon edule var. angustifolium (Miq.) Miq,.
The record derives from WCSP
(data supplied on 2012-03-26)
which reports it as a synonym (record 456061) with original publication details: Prodr. Syst. Cycad. 10, 22 1861.
This name record (from WCSP) was not included in version 1 of The Plant List. It is possible the same name was included from a different data source, to check this you can search for Dioon edule in version 1 of The Plant List.