Does Chen's work pose a problem for ToE?

Something, Jar, that seems to get forgotten is, other than a couple of creatures, what Cambrian life would look like, to the untrained eye, is a bunch of very small "worms" and "bugs"There is a big deal made of the fact that all the phyla were already represented. All that is needed for this is enough time for life to have diverged just enough to have the very basic characteristics that we use to classify phyla today. If one worm has a stiffen of cartilege like material down it's length and another does not they are, by today's definitions different phyla.This is, to me, no "big deal" indeed given a very few million years to diverge. Of course, it appears we still have some 10's of Myrs to diverge. Perhaps the mystery is, like the preceding 3 Gyrs with mostly unicellular life, NOT how rapidly life "exploded" but rather why it took many 10's of millions of year too do so.Pick a period of similar duration at a later date (and with lots of open niches to expand into) and you get the proliferation of mammals after the KT extinction as an example. I'd say that the later example looks more like an "explosion" and the pre-Cambrian example more like a slow smoulder.

I think you are missing the confusion, Mod. rand seems to think that the bilaterians found much earlier than the Cambrian are actually more advanced than those found later in the Cambrian.

Abundance is a kind of fuzzy term. Remember, Chiroptera, these dozen or so places where remarkable preservation has happened preserve even very, very small (microscopic and near) remains. In a small area there maybe many 1,000s of such creatures. That can be taken as "abundance". Of course, using that in this context isn't meaningful but it is typical.Stepping back a bit it seems we have about a dozen sites spread over nearly a billion years. It would seem to me that something occuring on 100 million year intervals qualifies as "rare". If these samples (at 100 Myr intervals) capture 100,000 animals ("abundant"?) then we are getting (on average -- meaningless in this case but fun to calculate) about 1 animal per 1,000 years --- "rare" I would say (with how many animals living in the 1,000 years?--- really, really rare). A silly argument but fun.