IPNI lists the name "Jacobaea arenaria" as invalid, as the attempt to publish it (http://old.ssbg.asu.ru/turcz/p58-63.pdf) failed to cite the location of publication of the "basionym" (https://ipni.org/n/20004937-1). Even were this not the case, though, the publication acknowledges that Senecio arenarius M.Bieb. is an illegitimate later homonym of Senecio arenarius Thunb. As such, it cannot act as a basionym, and the name "Jacobaea arenaria" would be treated as a replacement name. However, the authors listed Senecio grandidentatus in synonymy, and according to Article 11.4, should have taken the epithet from this name rather than publishing a replacement name. This combination was subsequently published, and is the correct name for this taxon.
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.
