Namacalathus is an animal fossil of problematic filiation that belongs to the Ediacárico Period. The only species N. hermanastes was described for the first time in 2000 by the Nama group, located in central and southern Namibia. The animal is most likely to be a Cnidaria of a bilaterian sponge or primitive. AU-Pb in zircons of fossiliferous rocks in Namibia and Oman provides an age for the Namacalathus zone in the range of 549 to 542 Ma, corresponding to that of Ediacara Late. These organisms and Cloudina are the earliest known evidence in the fossil record of the occurrence of skeletal calcification formation in metazoans, an important feature in animals that appear later in the Cambrian. There are only four cases of Namacalathus (Namibia, Canada, Oman, Siberia) known to date, all of which are found in association with Cloudina fossils. Among the fossil complex at the end of the Precambrian in the Nama group, Namibia, Namacalathus outnumber Cloudina and other poorly preserved and icnofossil taxa are found in the formation. The Nama Group fossils occur within thrombolytic facies of the immense proterozoic stromatolytic reefs. Namacalathus lived a benthic existence with its stem attached to the bottom of the sea or, possibly, the mats of algae growing on the surface of the reef.
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