 One concern one might have about de Queiroz’s attempt to unify the species category is that proponents of other species concepts would disagree with de Queiroz’s assertion that their disagreements are merely over evidence for the numbers and boundaries of species. Proponents of the interbreeding, ecological and phylogenetic approaches believe that they are identifying different types of lineages (interbreeding lineages, ecological lineages, phylogenetic lineages), not merely disagreeing over evidence for the same type of lineage. For example, when supporters of the interbreeding approach say that asexual organisms do not form species they are making a conceptual or ontological claim, not an operational claim. De Queiroz’s unified approach seems to mischaracterize disagreements among proponents of other species concepts.