Inferred phylogenetic relationships within the Brachiopoda have long been accepted as demonstrating repeated transitions from a phosphatic shell chemistry to a calcareous composition. This interpretation is reflected in the major subdivision of the phylum into the classes Inarticulata and Articulata. Cladistic analysis suggests, however, that the phosphatic‐shelled and the calcareous‐shelled Brachiopoda are sister groups that have had consistently separated shell chemistries from early in phylogenetic history. This separation is recognized in the class‐rank divisions Lingulata and Calciata, the former of which includes the new Subclass Lingulatea, whilst the latter includes the new Subclass Craniformea together with the ‘articulates’ of previous classifications. □Brachiopoda, cladistic analysis, Lingulata, Lingulatea, Calciata,
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