 PCASP3 is the ancestral copy and can be found in all deuterostomes, like sea urchin, lancelets, tunicates and lampreys (a non-jawed vertebrate).Notably, mammals have lost PCASP2 and PCASP3 and only have PCASP1 (MALT1).The non-deuterostome invertebrate type 1 paracaspase closest related to PCASP3 can surprisingly be found in molluscs, which could indicate that there were 2 paralog type 1 paracaspases present in the first bilaterans (like in cnidarians), and that different bilateran lineages have kept one or the other paralog.