Mickwitziids are a Cambrian group of shelly fossils with originally phosphatic valves, belonging to the Brachiopod stem group, and exemplified by the genus Mickwitzia – the other genera are Heliomedusa (a possible junior synonym of Mickwitzia?)

[2] The family Mickwitziidae is conceivably paraphyletic with respect to certain crown-group brachiopods.

[2] Heliomedusa orienta was first interpreted as a jellyfish - hence its name - but is now affiliated with Mickwitzia, as well as Craniopsids and Disciniids.

[7] In 2007 a new interpretation reconstructed Heliomedusa as being the other way up - swapping the identity of the dorsal and ventral valves.

They argue that the pedicle identified by Chen et al. (2007), and central to their "ventral valve as dorsal" argument, was instead an internal structure corresponding to an infilled gut.