End-Ediacaran extinction

[5] The transition from the White Sea to the Nama biota saw a major reduction in diversity that was not recovered during the interval of the depauperate Nama biota, which has been attributed to either increased biological competition[1] or an anoxic event[5] and in either case suggests that large-scale extinction began well before the boundary between the Ediacaran and Cambrian.

[citation needed] The fossil record of the earliest Cambrian, just after the Ediacaran period, shows a sudden increase in burrowing activity and diversity.

[7] One possible Ediacaran survivor whose status is still open to scrutiny is Ediacaria booleyi, a purported holdfast structure known from the upper Cambrian.

[12] Ordovician and Silurian Rutgersella[13] and Devonian Protonympha[14] have been interpreted as surviving vendobionts, comparable with Ediacaran Dickinsonia and Spriggina, respectively.

[16] The transition between the White Sea and Nama biotas near the end of the Ediacaran is reflected in the geological record by an increase in black shale deposition,[17] representing global anoxia.