Instead of 'evidence for taxon' I suggest 'taxon source' since 'evidence' is not semantically appropriate here.
(One finds evidence for a claim, or for the existence of a taxon, but not for a taxon per se. The existence of the taxon is not in dispute, and anyhow it can't be in dispute until we know what taxon is under discussion. 'Source' is also sort of funny but not nearly as bad since it admits to metonymy: to know what taxon we're talking about, one checks a source that gives information about the taxon, expressed using the taxon's name.)
Instead of 'evidence for taxon' I suggest 'taxon source' since 'evidence' is not semantically appropriate here.
(One finds evidence for a claim, or for the existence of a taxon, but not for a taxon per se. The existence of the taxon is not in dispute, and anyhow it can't be in dispute until we know what taxon is under discussion. 'Source' is also sort of funny but not nearly as bad since it admits to metonymy: to know what taxon we're talking about, one checks a source that gives information about the taxon, expressed using the taxon's name.)