There seems to be a burst of energy put into discovering new species that add to knowledge of the diversity of life in the Cambrian and earlier fossil fauna described in Gould's book about the Burgess Shale deposits in the Rocky Mountains of Canada. A recent issue of Science summarizes the results of the summer fossil collecting season of an additional site not far from the Burgess Shale site. Additional sites, especially in China, are major locations of fossils from the same general time over 540 million years ago,
The discoveries are largely more of the same - arthropod groups, some now extinct, and some ancestors of relatively rare living groups such as horseshoe crabs and onychophorans that have not greatly changed. Ancestral trees show relationships of major arthropod groups appearing rapidly during a few million years of time.
I do not have much hope of researchers finding fossils that clearly show the origins of annelids and mollusks more than indicated in earlier posts of this blog. It is a little bit like me, not much is new since I turned ninety.
Joe Engemannn Kalamazoo, Michigan November 30, 2018
The issue from the mid-November Science issue had a bit about discovery of a method providing information about epithelial layers formerly thought to be unable to present fossil evidence. It seems unlikely to provide reliable evidence leading to wholesale understanding of gross aspects of fossil structure, although interesting information seems to be revealed.
Arthropods ancestral to known groups may have not provided fossil evidence for a number of reasons such as - inaccessible ancient rock strata, lack of structures that fossilize, Isolation of one or more small sub-populations of a species provides opportunities for more rapid development of new species.
My shutdown of blogging for the past month had nothing to do with the current government shutdown other than my wasting my time thinking about the ridiculous current events.
Joe Engemann Kalamazoo, Michigan January 7, 2019
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