Cambrian Explosion Yuknessia Algal Fossil

Description: The first fossils of multicellular green algae appear in the Cambrian strata of the early Paleozoic Era. Yuknessia as shown here was a thin, frond-like green, carbonaceous algae resembling modern kelp. Complete algal fossils, identified as Yuknessia simplex and Margaretia dorus have also been found in the Burgess shale of Canada; both genera have been classified as Chlorophytes, a distinct branch of green algae from the Streptophytes that eventually gave rise to the land plants. This taxon has not been well studied.

Together with filamentous cyanobacteria (commonly called blue-green algae), algae like Yuknessia built large reef systems that not only supported Cambrian marine life, but photosynthetically augmented atmospheric oxygen levels thus further driving the amazing eukaryotic diversification known as the Cambrian Explosion.

Reference: The Fossils of the Burgess Shale by D. E. Briggs, et al.