In 2006, Seigler et. al. transferred this taxon from Acacia to the newly created genus Mariosousa. This was previously described in Prosopis, as Prosopis heterophylla in 1846, and as Acacia willardiana in 1890, so it is evident that they must have transferred it originally as M. heterophylla.
However, appealing to nomenclatural stability and the widespread use of the epithet "willardiana", they did so as M. willardiana, for which they proposed retaining A. willardiana over P. heterophylla in 2011, which was rejected.
Finally, in 2018 they formally published the current, and taxonomically more correct name.
Seigler, D. S., & Ebinger, J. E. (2018). New Combinations in Parasenegalia and Mariosousa (Fabaceae: Mimosoideae). Phytologia, 100(4), 256-259. (Σύνδεσμος)
Unintended disagreements occur when a parent (B) is
thinned by swapping a child (E) to another part of the
taxonomic tree, resulting in existing IDs of the parent being interpreted
as disagreements with existing IDs of the swapped child.
Identification
ID 2 of taxon E will be an unintended disagreement with ID 1 of taxon B after the taxon swap
If thinning a parent results in more than 10 unintended disagreements, you
should split the parent after swapping the child to replace existing IDs
of the parent (B) with IDs that don't disagree.
