Pursuit of a natural classification of diatoms: An incorrect comparison of published data

Williams and Kociolek (2007: Eur. J. Phycol., 42: 313-319) have presented an opinion paper in which they review some principles of classification and criticize the most recent classification of the diatoms by Medlin Kaczmarska (2004: Phycologia, 43: 245-270). In their critique of paraphyletic groups, they failed to consider one paraphyletic relationship that is most frequently revealed by molecular data, which in part justifies the recognition of paraphyletic taxa among certain diatom genera. In their criticism of the most recent classification system of the diatoms, they have misinterpreted and misrepresented much of the molecular data that they have used as evidence against this classification system and thus have made incorrect comparisons among published phylogenies of the diatoms.