dubious for taxon S dubious_for_taxon T if it is probably the case that no instances of S can be found in any instance of T. This relation lacks a strong logical interpretation, but can be used in place of never_in_taxon where it is desirable to state that the definition of the class is too strict for the taxon under consideration, but placing a never_in_taxon link would result in a chain of inconsistencies that will take ongoing coordinated effort to resolve. Example: metencephalon in teleost taxonomic class assertion Christopher J. Mungall