. "forelimb always_present_in_taxon Euarchontoglires" . "never lost in" . . "brain always_present_in_taxon 'Vertebrata'" . "This is a very strong relation. Often we will not have enough evidence to know for sure that there are no species within a lineage that lack the structure - loss is common in evolution. However, there are some statements we can make with confidence - no vertebrate lineage could persist without a brain or a heart. All primates are limbed. " . "always present in taxon" . "S always_present_in_taxon T if every fully formed member of taxon T has part some S, or is an instance of S" .