LIFE × EVOLUTION

Cells That Stayed Together

~1.6 billion years ago

Proterozoic · Paleoproterozoic · Statherian

Cells divided and did not let go. In rocks between 1.63 and 1.56 billion years old, in North China and in central India, three separate finds show the result: unbranched filaments whose cells reach a fifth of a millimetre across, red algae preserved down to their internal partitions, and, at the young end of that range, carbon films of blades big enough to see. All were built of many cells working as one body, and all were probably photosynthetic.

Why it matters

Simple multicellularity turns out to be nearly as old as the complex cell itself: a few hundred million years separate the two. Then a billion years pass before animals make anything spectacular of it. Sticking together was easy. Becoming an organism was not.

Dating & uncertainty

Three independent assemblages, from North China and from India, fall between 1.63 and 1.56 Ga. Assigning fossil cells to a modern group rests on shape, size and preservation, so their affinities are argued case by case.

Sources

1. Miao et al. (2024), Science Advances · 1.63-billion-year-old multicellular eukaryotes from the Chuanlinggou Formation in North China
2. Zhu et al. (2016), Nature Communications · Decimetre-scale multicellular eukaryotes from the 1.56-billion-year-old Gaoyuzhuang Formation in North China
3. Bengtson et al. (2017), PLoS Biology · Three-dimensional preservation of cellular and subcellular structures suggests 1.6 billion-year-old crown-group red algae

Earth history as one day

15:22:598 h 37 min before midnight

if Earth’s 4.54 billion years were compressed into a single day