Multicellular Macrofossils of the Francevillian Series
fossil evidence of the earliest multicellularity comes from
the 2100 million year old so called Francevillian B2 Group
Fossils (FB2) in the area that is now southeastern Gabon
laying west of the Congo in Africa. The strata, also called
black shales, yields pyritized macrofossils (the Francevillian
biota) of diverse morphology measuring one to more than 10
well as acritarch microfossils. The age of these putative
with the large rise in atmospheric oxygen that began at about
2300 million years ago, known as the Great Oxygenation Event.
Thus, the age is consistent with the theory that oxygen production
by photosynthetic organisms (i.e., mostly cyanobacteria)
exceeded the rate of absorption in the oceans and its rocks,
atmospheric oxygen levels to begin to rise from negligible
levels. Such atmospheric oxygenation would have, among other
things, sparked evolution among eukaryotes at around 2300
mya. The reason these fossil survived the hardships of geological
time was their pyritization, a process where the organic matter
of the carbon by
ferrous iron is available.
such fossils are always controversial, with some scientists
insisting they are pseudofossils, the FB2 fossils do appear
to be organisms that while spatially separated, also led a
Most importantly, the cells may have been differentiated.
Diffrentiated means they exhibit patterns of growth determined
from the fossil
morphologies that are
of intercellular signaling and thus of mutually synchronized
responses that are the hallmarks of multicellular organization.
The evolutionary leap to multicellularity would require the
distinct cells to adhere, communicate, and cooperate with
one another, and to specialize their respective contributions
the aggregated organism. The aggregated organism would also
need to reject cells providing to collective benefit (i.e.,
similar to immune rejection).
evolutionary leap to multicellularity is believed to have occurred
repeatedly in the evolution of life, and through many
different biological pathways. The distinct and independent cells
evolved the means to symbiotically organize, thereby thrive,
and with such organization ultimately becoming genetically regulated
so the multicellular organism operates synergistically in energy
production and consumption, survival, and reproduction. Presuming
that the fossils of the Francevillian Series of Gabon are of
ancient multicellular life, and possibly eukaryotes, it is
interesting to consider that they
were early in
what is called
the Boring Billion years
of evolutionary stasis of such organisms,
that would persist until the Ediacaran around
635 mya and the
Cambrian Explosion at
about 521 mya.
Albani A, Bengtson S, Canfield DE, Bekker A, Macchiarelli R,
et al. (2010) Large colonial organisms with coordinated growth
in oxygenated environments 2.1 Gyr ago. Nature 466: 100–104.
El Albani, Abderrazak; Bengtson, Stefan;
Canfield, Donald E.; Riboulleau, Armelle; Rollion Bard, Claire;
Macchiarelli, Roberto et al. (2014). "The 2.1 Ga Old Francevillian
Biota: Biogenicity, Taphonomy and Biodiversity". PLoS
ONE 9 (6).
Maxmen, A (2010). Ancient macrofossils
unearthed in West Africa. Nature News