Comment on Franz et al. 2023: A reinterpretation of the 1.5 billion year old Volyn ‘biota’ of Ukraine, and discussion of the evolution of the eukaryotes
Abstract. Franz et. al. (Biogeosciences 20, 1901–1924, 2023) report a diverse and three-dimensionally preserved suite of mid-Proterozoic microfossils from miarolotic cavities within the granitic Volyn pegmatite field, a major granitic plutonic complex in NW Ukraine. The biota is dated at between ~1.76 Ga and ~1.5 Ga and includes fungus-like objects. This biota is reported as evidence of organisms living within the continental lithosphere, illuminating part of a ~1.8–0.8 billion year interval of the Proterozoic Eon characterised by relatively low climatic variability and slow biological evolution. We show that at least some of this putative diversity represents modern contamination including plant hairs, a distinctive pollen grain assignable to the extant conifer genus Pinus, and likely later fungal growth. Comparable diversity is shown to exist in modern museum dust, this calling into question whether any part of the Volyn ‘biota’ is biological in origin while emphasising the need for scrupulous care in collecting, analysing, and identifying Precambrian microfossils.
Viewed (geographical distribution)