Ichthyostraca is a class of parasitic crustaceans. It is composed of two subclasses; Pentastomida and Branchiura. They mainly parasitize various different vertebrates and feed on their blood or mucus.[2][3]
References
^D. Walossek & K. J. Müller (1994). "Pentastomid parasites from the Lower Palaeozoic of Sweden". Transactions of the Royal Society of Edinburgh: Earth Sciences. 85: 1–37. doi:10.1017/s0263593300006295. S2CID86957051.