Namapoikia rietoogensis is among the earliest known animals to produce a calcareous (probably aragonite[1]) skeleton.

[2] Known from the Ediacaran period, before the Cambrian explosion of calcifying animals, the long-lived organism grew up to a metre in diameter and resembles a colonial sponge.

[3][4] It was an encruster, filling vertical fissures in the reefs in which it originally grew.

Its mineralogy and accretionary style has been compared with that of the Lophotrochozoans,[6] though its unfamiliar morphology suggests a stem-group or deeper affiliation to this group.

[7] It grew in spurts, first emplacing an organic skeleton, then filling this in with aragonite.