red algae ~1.2: eukaryotic microfossils 1.8 Ga
||Olivia P. Judson, The energy expansions of evolution, Nature ecology & evolution, 28 April 2017 | Volume: 1 | Article number: 0138 p.3 right column 2nd paragraph
|| Nicholas J. Butterfield, Bangiomorpha pubescens n. gen., n. sp.: implications for the evolution of sex, multicellularity, and the Mesoproterozoic/Neoproterozoic radiation of eukaryotes, Paleobiology 26(3):386-404. 2000 link  Knoll AH, Paleobiological perspectives on early eukaryotic evolution. Cold Spring Harb Perspect Biol. 2014 Jan 16(1). pii: a016121. doi: 10.1101/cshperspect.a016121. PubMed ID24384569
||P.3 right column 2nd paragraph: "During this epoch, two momentous events took place: the emergence of eukaryotes and the emergence of the lineage that would eventually produce land plants. Both events represent fusions between two previously independent lineages, an archaeon and an alphaproteobacterium in the case of eukaryotes (refs 73,74), and a eukaryote and a cyanobacterium in the case of the plant lineage (ref 75), the alphaproteobacterium evolved to become the mitochondrion, the cyanobacterium, the chloroplast. Both events thus also represent important shifts in the capacity for organisms to transduce energy. Fossils of red algae show that both events had taken place by ~1.2 Ga (primary source 76), and microfossils that are probably eukaryotic in origin date to 1.8 Ga (primary source 77)."