Diskagma

Diskagma ("disc-like fragment") is a genus of problematic fossil from a Paleoproterozoic (2200 million years old) paleosol from South Africa, and significant as one of the oldest likely eukaryotes and some of the earliest evidence for megascopic life on land.

[1] Diskagma buttonii is a small fossil less than 1mm in length found within the surface horizon of a vertisol paleosol above the Hekpoort Basalt dated to 2200 million years old.

The opacity of the matrix and the size of the fossil meant that its three dimensional structure required imaging by computer-assisted x-ray tomography using a cyclotron source[1] The fossils are shaped like an urn with an apical cup, which is filled with filamentous structures whose exact nature is uncertain due to recrystallization of the matrix under greenschist facies metamorphism.

Although Precambrian landscapes are customarily regarded as barren as the surface of Mars, Diskagma is evidence for very early life on land.

Furthermore, at 2200 million years old, Diskagma was larger than coeval marine microbes of the Gunflint Chert, and more complex than stromatolites.

Reconstruction of Diskagma buttonii .
Poorly preserved filamentous structures in the apex of Diskagma buttonii .
3D reconstruction of Diskagma buttonii