The brachiopod order Atrypida originated in the Middle Ordovician and went extinct in the Late Devonian. Few cladistic studies have been undertaken for this group. Here we investigate their early evolution through the Silurian time. We present a parsimony-based phylogenetic analysis of 41 characters and 70 genera representing all the early taxonomic groups within the order. The stratigraphic record of the fossil genera analysed here strongly supports the parsimony phylogeny. Most currently recognized subfamilies and...