Taxonomy
A scanning electron microscope photograph of expanded larval stage of Microdajus attached to its host: the posterior sac contains a developing adult male. © Natural History Museum, London
Microdajus pectinatus is a tantulocaridan - one of a handful of British representatives of this group which was first recognised as a distinct subclass of crustacea in 1983.
Tantulocaridans are most closely related to the barnacles. They have a body plan in the tantulus larval stage that is similar to larval barnacles, and their reproductive structures are similarly positioned along the body. However, they lack the typical larval stage enclosed within a bivalved shell that characterises barnacle larvae.
