Three-dimensional reconstructions of the putative metazoan <i>Namapoikia</i> show that it was a microbial construction

Abstract

Significance Animals that build skeletons have an outsized impact on Earth’s biological, geochemical, and sedimentological cycles. To determine when, where, and why metazoan biomineralization first emerged, it is necessary to study the earliest record of skeletal animals. This record is made up of four genera from the Ediacaran period: Namacalathus , Cloudina , Sinotubulites , and Namapoikia . Here, we measure three-dimensional reconstructions of Namapoikia to test the hypothesis that it is a calcifying sponge. We find that Namapoikia lacks the physical characteristics expected of a sponge, or, for that matter, an animal.

Topics & Concepts