Cyanobacteria or rhodophyta? Interpretation of a precambrian microfossil

Discovery and interpretation of a filamentous microfossil from the late Proterozoic Narssârssuk Formation in northwest Greenland approximately 770 Ma is reported here. This microfossil is preserved as a single occurrence in a silicified carbonate sequence containing stromatolitic laminae. Based on the absence of other occurrences and its microstratigraphic association with planktonic microfossils, the microfossil is interpreted as allochthonous. The microfossil is similar to two extant taxa representing different kingdoms: one prokaryote, Johannesbaptistia pellucida (cyanobacteria) and one eukaryote, Bangia sp. (rhodophytes). Definitive identification, due to the lack of distinctive morphology, could not be made.