Evolution: Bilaterians & Ediacarans (Introduction)

by David Turell , Thursday, September 10, 2020, 00:10 (1537 days ago) @ David Turell

A discovery of one specific bilaterian fossil:

https://evolutionnews.org/2020/09/was-kimberella-a-precambrian-mollusk/

"Kimberella indeed represents the strongest case for a bilaterian animal from the Ediacaran era. This is important because it would not only provide a minimum age for the earliest origin of Bilateria but would also predate the Cambrian explosion of bilaterian animal phyla as a kind of “advance guard”

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"Because of the enormous importance of this crucial taxon for evolutionary biology, I reviewed for this article series every single paper that was ever published on it or even only discussed it, so that this synopsis and bibliography should even prove to be useful for experts, as nothing comparably comprehensive and up to date exists anywhere else.

"The hypothesis of a molluscan affinity of Kimberella is still prevailing in the technical and popular literature on Ediacaran biota.

"Peter Godfrey-Smith (2016), who wrote about Kimberella as the possible earliest mollusk in his bestselling book Other Minds: The Octopus, the Sea, and the Deep Origins of Consciousness, is quoted by McMenamin (2018) with the following remarkable statement: “One of my correspondents expressed concern that I was perpetuating a dubious interpretation of Kimberella as a mollusk; for another, Kimberella-as-mollusk is crucial to the interpretation of early bilaterian evolution.”

"In addition, eminent intelligent design theorist Stephen C. Meyer has acknowledged in his seminal book Darwin’s Doubt (Meyer 2013) that Kimberella could be an Ediacaran bilaterian animal and maybe even a mollusk. This was considered by other ID proponents as maybe too generous (Evolution News 2016). Let’s see what the published evidence says and follow the evidence wherever it leads."

Comment: Edicarans are very simple organisms and the bilaterians are symmetrical simple sac-like forms found in this period. So far no evidence of complex organ systems as in the Cambrian and better definition is very important as we study the so-called Cambrian gap in complexity. So far nothing closes the gap. I will follow and present Bechly 's follow-up articles.