Bangiomorpha: the first sex, the first true multicellular life
What happened
In rocks first collected on Baffin and Somerset Islands in Arctic Canada, paleontologist Nicholas Butterfield described a fossil red alga, Bangiomorpha pubescens, built from differentiated filaments of cells rather than a single cell alone, some specialized for spores and others for reproduction. A 2018 re-dating using rhenium-osmium radiometric methods pinned the fossil to 1.047 billion years old, about 150 million years younger than earlier estimates, and McGill University, whose researchers led that dating work, calls Bangiomorpha the oldest known direct ancestor of modern plants and animals. Butterfield's original description argued the fossil's cell differentiation is best explained as evidence of sexual reproduction, the oldest such evidence on record, arising alongside true multicellularity rather than after it.
Why it matters
Nearly all complex life today, plants, animals, fungi, reproduces sexually and builds bodies from many specialized cell types. Bangiomorpha suggests these two traits, sex and true multicellularity, are old partners that arose together rather than separately, more than a billion years before large animals existed to need either one.
How we know
The claim rests on the fossil's own anatomy: distinct cell types arranged in a pattern that matches the reproductive structures of living red algae, not a stray growth form. The refined 1.047-billion-year age comes from dating the volcanic ash layers bracketing the fossil-bearing rock, a more precise method than the broader estimates used when the fossil was first described in 2000.
Sources
- McGill University Newsroom. Origins of photosynthesis in plants dated to 1.25 billion years ago (2018) · Reputable sourcemcgill.ca · The domain "mcgill.ca" is on our Reputable source registry. · Link is live and its text matches the event's key terms (Jul 2026)
- CBC News. Fossils of earliest organisms that had sex are a billion years old (2017) · Reputable sourcecbc.ca · The domain "cbc.ca" is on our Reputable source registry. · Link is live and its text matches the event's key terms (Jul 2026)
See something wrong? . Corrections with a source get fixed fastest.
Part of a timelineEarly Life on Earth9 events · How a single microbial ancestor became a planet run by oxygen, complex cells, and eventually animals, from LUCA to the doorstep of the Cambrian explosion.View all →