Re: Cambrian explosion may have occurred 15 million years earlier than previously thought

On 6/29/2025 2:35 PM, Pro Plyd wrote:

 https://phys.org/news/2025-06-cambrian-explosion-million-years-earlier.html
 The Cambrian explosion was an extraordinary
phenomenon in the evolution of life on the planet
that led to the emergence of many animal phyla and
the diversification of species. During this period,
some 530 million years ago, most of the basic body
plans of organisms that have survived to the present
day emerged. However, this great explosion of life
that changed the evolutionary landscape on Earth
may have occurred millions of years earlier than
previously thought, a hypothesis now reinforced in
a study published in the journal Geology.
 This is a main conclusion of a new study that
analyses the body profiles of organisms—symmetry,
segmented bodies, exoskeletons, etc.—from around
545 million years ago by analyzing trace fossils,
which are the fossilized marks in rocks and sediments
left by the activity of organisms in the past.
...
  https://pubs.geoscienceworld.org/gsa/geology/article/doi/10.1130/ G53332.1/655874/Quantitative-decoding-of-Ediacaran-locomotory
 Quantitative decoding of Ediacaran locomotory trace
fossil morphologies: Evidence for the emergence of
slender anterior-posterior body profiles

These guys estimated that a lot of phyla evolved before the Cambrian explosion.
https://www.science.org/doi/10.1126/sciadv.adp7161
Metazoan separation from Porifera at around 600 million years ago. Bilateria evolved over 570 million years ago.  The protostome deuterostome split occurred over 564 million years ago, and Vertebrata evolved from Chordata around 559 million years ago, over 20 million years before the Cambrian explosion supposedly started.  They think that mollucs and arthropods separated around 561 million years ago with mussel and cuttlefish separating around 541 million years ago and Nematodes and arthropods separating 551 million years ago.  All before the start of the Cambrian around 538 million years ago.
Ron Okimoto