Deep diversity in Lophotrochozoa.

[erik simpson]

https://www.cell.com/current-biology/fulltext/S0960-9822(22)01455-5

"Among extant animals, Lophotrochozoa accounts for the majority of phyla.1
This bilaterian clade radiated rapidly during the Cambrian explosion, obfuscating its phylogenetic relationships and rendering many aspects of its early evolution uncertain. Many early lophotrochozoans are known only from isolated skeletal microfossils, “small shelly fossils,” often derived from larger animals with complex multi-element skeletons.2
The discovery of articulated fossils has revealed surprising insights into the animals from which these skeletal pieces were derived, such as paired shells in the mollusc Halkieria.3
Tommotiids are a key group of phosphatic early skeletal fossils that first appear in the late early Cambrian.4
,5
Although their affinities were previously obscure, discoveries of partial scleritomes and investigations of growth and microstructure6
provide links with Brachiopoda7
,8
and Phoronida,9
two of the lophophorate phyla. By contrast, the body plan of camenellan tommotiids remains a palaeontological mystery, with hypothetical reconstructions representing motile, benthic, dorsally armored worms.4
,10
Here, we describe an articulated camenellan (Wufengella bengtsoni gen. et sp. nov.) from the Cambrian Chengjiang Biota, China, revealing the morphology of the scleritome and the first soft tissues from an adult tommotiid. Wufengella carries two dorsal rows of sclerites in a highly asymmetric arrangement, flanked by smaller, cap-shaped sclerites. The scleritome was fringed by iterated fascicles of chaetae and two layers of flattened lobes. Phylogenetic analysis confirms that camenellans occupy a deep branch in lophophorate phylogeny, prior to the acquisition of a sessile lifestyle. Wufengella reveals direct evidence for a metameric body plan reminiscent of annelids early in the evolutionary history of lophophorates.11
,12"

Another illustration that in the early Cambrian, many currently known "major phyla" probably wouldn't have been so classified by a Cambrian Linnaeus.

[John Harshman]

Halkieriids are molluscs?

Well, here's the reference, but I can only see the abstract, and I can't
tell from that whether the paper does make that claim. It compares
Halkieria with Wiwaxia, not generally supposed to be a mollusc, though
often thought to be an annelid. Perhaps this just shows your point, that
really ancient members of separate phyla were not so separate.

https://www.nature.com/articles/345802a0

[erik simpson]

Halkieriids (and Wiwaxiids) are still problematic, after all these years. Here's an
interesting article relevant to the subject, and remarlably, open access:

https://www.nature.com/articles/s41598-017-16304-6

[John Harshman]

And these are all the animals Steven Meyer and the creationists claim
don't exist.

[Peter Nyikos]

John's parting shot suggests that moving this thread to talk.origins
might generate a good deal of interest.

The following is typical of the cluelessness of run of the mill
anti-creationist [as distinct from anti-creationism, which I am] zealots:

> And these are all the animals Steven Meyer and the creationists claim
> don't exist.

Meyer was well aware of Cambrian animals of problematic affinities,
including Wiwaxia, and also Amiskwia, Eldonia, and Nectocaris,
and took them in his stride.

And the closing words of the abstract of the very paper you
are citing should have given you pause:

"On this view, the absence of fossil Ediacaran sclerites is evidence against any ‘Precambrian prelude’ to the explosive diversification of these phyla in the Cambrian, c. 540–530 million years ago."

Prothero might be turning in his grave, were he not still alive. :) :)


Peter Nyikos

[Glenn]

This language in the Introduction struck me as being odd:

"The reconstructed origins of the molluscan lineage, for example, have been overhauled in order to accommodate two emblematic Cambrian taxa"

[John Harshman]

Well, one of us is clueless on this point. We may disagree on which one.

>> And these are all the animals Steven Meyer and the creationists claim
>> don't exist.
>
> Meyer was well aware of Cambrian animals of problematic affinities,
> including Wiwaxia, and also Amiskwia, Eldonia, and Nectocaris,
> and took them in his stride.

By "in his stride" you mean that he ignored the fact that several of
them contradicted his claim that there were no intermediates between
phyla. But the part about ignoring them was that he ignored the small,
shelly fauna that includes halkieriids and tommotiids, and that are
precursors to the Cambrian explosion.

> And the closing words of the abstract of the very paper you
> are citing should have given you pause:
>
> "On this view, the absence of fossil Ediacaran sclerites is evidence against any ‘Precambrian prelude’ to the explosive diversification of these phyla in the Cambrian, c. 540–530 million years ago."

You will note that this places the beginning of the Cambrian explosion
considerably before the time that Meyer attributes to it, in the
Chengjiang fauna, and long before the fossil appearance of most phyla.
This explosive diversification they mention is not shown in the fossil
record until Cambrian Stage 3, about 520 ma. Meyer makes no distinction
between "Cambrian" and "Cambrian Stage 3".

> Prothero might be turning in his grave, were he not still alive. :) :)

Whatever that means.

[Peter Nyikos]

On Tuesday, September 27, 2022 at 10:59:53 PM UTC-4, John Harshman wrote:
> On 9/27/22 6:31 PM, Peter Nyikos wrote:

> > John's parting shot suggests that moving this thread to talk.origins
> > might generate a good deal of interest.

You didn't comment on this. Do you disagree?

Time will tell. I hope Glenn can follow our debate.

You are off to a bad start below by saying "you mean" when what I meant
was that Meyer did not claim that the Cambrian explosion
gave rise to animals that cannot be placed into extant phyla.
d
Your comment was ambiguous, and mean-spirited:

> >> And these are all the animals Steven Meyer and the creationists claim
> >> don't exist.
> >
> > Meyer was well aware of Cambrian animals of problematic affinities,
> > including Wiwaxia, and also Amiskwia, Eldonia, and Nectocaris,
> > and took them in his stride.

> By "in his stride" you mean that he ignored the fact that several of
> them contradicted his claim that there were no intermediates between phyla.

That "fact" remains to be seen. Just what do you mean by "intermediates"?
It would be anti-cladism heresy for you to claim that any of the groups that
Erik identified were paraphyletic, wouldn't it?

So, what did you mean, and where is your evidence?

> But the part about ignoring them was that he ignored the small,
> shelly fauna that includes halkieriids and tommotiids, and that are
> precursors to the Cambrian explosion.

I do recall an article about the "shellies" in a DI webpage, probably Evolution News,
where this omission was addressed.


In any event, the sentence I quoted below puts these particular
shellies in the Cambrian:

> > And the closing words of the abstract of the very paper you
> > are citing should have given you pause:
> >
> > "On this view, the absence of fossil Ediacaran sclerites is evidence against any ‘Precambrian prelude’ to the explosive diversification of these phyla in the Cambrian, c. 540–530 million years ago."


> You will note that this places the beginning of the Cambrian explosion
> considerably before the time that Meyer attributes to it, in the
> Chengjiang fauna, and long before the fossil appearance of most phyla.

I do not note any such thing. Meyer is very careful to note that "the Cambrian
explosion" has been given many different meanings by different people, and that he is primarily
concerned with what he calls "the main pulse" of the Cambrian explosion,
which lasted approximately 6 million years and saw the emergence of
13 animal phyla in the fossil record by reckoning of Erwin et al.,
Science 334 (2011) 1091-97 and 16 animal phyla in a slightly different
ca. 6 my period by reckoning of Bowring et al, Science 261 (1993) 1293-98.

> This explosive diversification they mention is not shown in the fossil
> record until Cambrian Stage 3, about 520 ma.

What is your reference for this claim? It is inconsistent with what "they"
wrote and I quoted: "...c. 540–530 million years ago."

It is also inconsistent with where Meyer centered the "main pulse": 530-525 mya.

>Meyer makes no distinction
> between "Cambrian" and "Cambrian Stage 3".

This is absurd on the face of it. What are you basing this claim on?

> > Prothero might be turning in his grave, were he not still alive. :) :)

> Whatever that means.

You have a very leaky memory. Don't you remember how Prothero
wiped out all our comments and questions on his blog except your comment which
included the question of how he estimated 80 million years for what HE called
the Cambrian explosion? He left in his response which evaded the
question. When he saw how you politely pointed this out, he went on his rampage
of deleting about 40 questions and comments, including your polite pointing-out.


Peter Nyikos
Professor, Dept. of Mathematics -- standard disclaimer--
University of South Carolina
http://people.math.sc.edu/nyikos

[John Harshman]

On 9/28/22 2:32 PM, Peter Nyikos wrote:
> On Tuesday, September 27, 2022 at 10:59:53 PM UTC-4, John Harshman wrote:
>> On 9/27/22 6:31 PM, Peter Nyikos wrote:
>
>>> John's parting shot suggests that moving this thread to talk.origins
>>> might generate a good deal of interest.
>
> You didn't comment on this. Do you disagree?

Feel free to crosspost if you think so.

Why would you hope that? Glenn is a troll. Have you read anything he's
posted in the past week or two? If that's your hope, maybe crossposting
is a bad idea.

> You are off to a bad start below by saying "you mean" when what I meant
> was that Meyer did not claim that the Cambrian explosion
> gave rise to animals that cannot be placed into extant phyla.
> d
> Your comment was ambiguous, and mean-spirited:

What did he claim, then? Wouldn't that claim, if he had made it, be correct?

>>>> And these are all the animals Steven Meyer and the creationists claim
>>>> don't exist.
>>>
>>> Meyer was well aware of Cambrian animals of problematic affinities,
>>> including Wiwaxia, and also Amiskwia, Eldonia, and Nectocaris,
>>> and took them in his stride.
>
>> By "in his stride" you mean that he ignored the fact that several of
>> them contradicted his claim that there were no intermediates between phyla.
>
> That "fact" remains to be seen. Just what do you mean by "intermediates"?
> It would be anti-cladism heresy for you to claim that any of the groups that
> Erik identified were paraphyletic, wouldn't it?

No, it would not, but I don't claim such a thing anyway.

> So, what did you mean, and where is your evidence?

I suggest reading Budd G.E., Jensen S. A critical reappraisal of the
fossil record of the bilaterian phyla. Biological Reviews 2000; 75:253-295.

Essentially, many Cambrian taxa are stem-members of their associated
phyla and some of them are stem-members of groups of phyla. "Lobopods",
for example, are stem-members of different ecdysozoan phyla. Halkieriids
and/or tommotiids may (i.e., less certainly) be stem-lophotrochozoans.
Cloudina and Namacalathus are others; bonus, they're Precambrian.

>> But the part about ignoring them was that he ignored the small,
>> shelly fauna that includes halkieriids and tommotiids, and that are
>> precursors to the Cambrian explosion.
>
> I do recall an article about the "shellies" in a DI webpage, probably Evolution News,
> where this omission was addressed.

In what way was it addressed?

> In any event, the sentence I quoted below puts these particular
> shellies in the Cambrian:

Yes, mostly, though a few are Precambrian. But the point is that they
predate the visible explosion, i.e. the appearance of most phyla, which
isn't until Cambrian Stage 3.

>>> And the closing words of the abstract of the very paper you
>>> are citing should have given you pause:
>>>
>>> "On this view, the absence of fossil Ediacaran sclerites is evidence against any ‘Precambrian prelude’ to the explosive diversification of these phyla in the Cambrian, c. 540–530 million years ago."
>
>
>> You will note that this places the beginning of the Cambrian explosion
>> considerably before the time that Meyer attributes to it, in the
>> Chengjiang fauna, and long before the fossil appearance of most phyla.
>
> I do not note any such thing. Meyer is very careful to note that "the Cambrian
> explosion" has been given many different meanings by different people, and that he is primarily
> concerned with what he calls "the main pulse" of the Cambrian explosion,
> which lasted approximately 6 million years and saw the emergence of
> 13 animal phyla in the fossil record by reckoning of Erwin et al.,
> Science 334 (2011) 1091-97 and 16 animal phyla in a slightly different
> ca. 6 my period by reckoning of Bowring et al, Science 261 (1993) 1293-98.

What they're talking about there is Cambrian Stage 3, long after the
rise of the small shellies. Meyer, and perhaps you also, is confused
about the difference between the fossil record and the actual origins of
taxa. The small shellies and the ichnofossil record are clues that the
explosion is underway considerably before we get a good look at it. And
also evidence that it was a gradual expansion.

>> This explosive diversification they mention is not shown in the fossil
>> record until Cambrian Stage 3, about 520 ma.
>
> What is your reference for this claim? It is inconsistent with what "they"
> wrote and I quoted: "...c. 540–530 million years ago."

Try Erwin & Valentine. Did you ever read it? If you're at all interested
in the Cambrian explosion, it's the essential reference. Budd & Jensen
is great too.

> It is also inconsistent with where Meyer centered the "main pulse": 530-525 mya.

What is Meyer's reference for that claim? Does that reference support
the claim? You should check.

>> Meyer makes no distinction
>> between "Cambrian" and "Cambrian Stage 3".
>
> This is absurd on the face of it. What are you basing this claim on?

The fact that he fails to distinguish between "Cambrian", which began
542ma, and "Cambrian explosion", the fossil appearance of most phyla,
which happened around 520ma with the Chengjiang and Sirius Passet fauna,
as well as the worldwide first appearance of trilobites.

>>> Prothero might be turning in his grave, were he not still alive. :) :)
>
>> Whatever that means.
>
> You have a very leaky memory. Don't you remember how Prothero
> wiped out all our comments and questions on his blog except your comment which
> included the question of how he estimated 80 million years for what HE called
> the Cambrian explosion? He left in his response which evaded the
> question. When he saw how you politely pointed this out, he went on his rampage
> of deleting about 40 questions and comments, including your polite pointing-out.

I didn't know he had done that much, but at any rate how would that be
relevant to the present case? Or did you just want to revive a grievance
against him?

[Peter Nyikos]

On Wednesday, September 28, 2022 at 5:53:16 PM UTC-4, John Harshman wrote:
> On 9/28/22 2:32 PM, Peter Nyikos wrote:
> > On Tuesday, September 27, 2022 at 10:59:53 PM UTC-4, John Harshman wrote:
> >> On 9/27/22 6:31 PM, Peter Nyikos wrote:
> >
> >>> John's parting shot suggests that moving this thread to talk.origins
> >>> might generate a good deal of interest.
> >
> > You didn't comment on this. Do you disagree?

> Feel free to crosspost if you think so.

Unlike old Google groups, the two newer versions do not make
crossposting possible. So if you don't want us moving this to
talk.origins, I'm staying put here.

> >>> On Tuesday, September 27, 2022 at 6:43:30 PM UTC-4, John Harshman wrote:
> >>>> On 9/27/22 11:19 AM, erik simpson wrote:
> >>>>> On Tuesday, September 27, 2022 at 9:39:32 AM UTC-7, John Harshman wrote:
> >>>>>> On 9/27/22 9:22 AM, erik simpson wrote:
> >>>>>>> https://www.cell.com/current-biology/fulltext/S0960-9822(22)01455-5
> >>>>>>>
> >>>>>>> "Among extant animals, Lophotrochozoa accounts for the majority of phyla.1
> >>>>>>> This bilaterian clade radiated rapidly during the Cambrian explosion, obfuscating its phylogenetic relationships and rendering many aspects of its early evolution uncertain. Many early lophotrochozoans are known only from isolated skeletal microfossils, “small shelly fossils,” often derived from larger animals with complex multi-element skeletons.2
> >>>>>>> The discovery of articulated fossils has revealed surprising insights into the animals from which these skeletal pieces were derived, such as paired shells in the mollusc Halkieria.3
> >>>>>>> Tommotiids are a key group of phosphatic early skeletal fossils that first appear in the late early Cambrian.4
> >>>>>>> ,5
> >>>>>>> Although their affinities were previously obscure, discoveries of partial scleritomes and investigations of growth and microstructure6
> >>>>>>> provide links with Brachiopoda7
> >>>>>>> ,8
> >>>>>>> and Phoronida,9
> >>>>>>> two of the lophophorate phyla. By contrast, the body plan of camenellan tommotiids remains a palaeontological mystery, with hypothetical reconstructions representing motile, benthic, dorsally armored worms.4
> >>>>>>> ,10
> >>>>>>> Here, we describe an articulated camenellan (Wufengella bengtsoni gen. et sp. nov.) from the Cambrian Chengjiang Biota, China, revealing the morphology of the scleritome and the first soft tissues from an adult tommotiid. Wufengella carries two dorsal rows of sclerites in a highly asymmetric arrangement, flanked by smaller, cap-shaped sclerites. The scleritome was fringed by iterated fascicles of chaetae and two layers of flattened lobes. Phylogenetic analysis confirms that camenellans occupy a deep branch in lophophorate phylogeny, prior to the acquisition of a sessile lifestyle. Wufengella reveals direct evidence for a metameric body plan reminiscent of annelids early in the evolutionary history of lophophorates.11
> >>>>>>> ,12"
> >>>>>>>
> >>>>>>> Another illustration that in the early Cambrian, many currently known "major phyla" probably wouldn't have been so classified by a Cambrian Linnaeus

On the other hand, I've commented that if Linnaeus had been into subclasses, he would probably
have split Theria into Marsupilia, Cetacea, Chiroptera, and all other placentals.

But Harshman treated this as if it were a baseless speculation, and *a fortiori* I treat
Erik's "probably" in the same way.

> >>>>>> Halkieriids are molluscs?
> >>>>>>
> >>>>>> Well, here's the reference, but I can only see the abstract, and I can't
> >>>>>> tell from that whether the paper does make that claim. It compares
> >>>>>> Halkieria with Wiwaxia, not generally supposed to be a mollusc, though
> >>>>>> often thought to be an annelid. Perhaps this just shows your point, that
> >>>>>> really ancient members of separate phyla were not so separate.

Or perhaps not.

> >>>>>> https://www.nature.com/articles/345802a0
> >>>>>
> >>>>> Halkieriids (and Wiwaxiids) are still problematic, after all these years. Here's an
> >>>>> interesting article relevant to the subject, and remarlably, open access:
> >>>>>
> >>>>> https://www.nature.com/articles/s41598-017-16304-6
> >>>
> >>> The following is typical of the cluelessness of run of the mill
> >>> anti-creationist [as distinct from anti-creationism, which I am] zealots:
> >
> >> Well, one of us is clueless on this point. We may disagree on which one.
> >
> > Time will tell. I hope Glenn can follow our debate.

> Why would you hope that?

I'm hoping there will be a witness to your behavior who is not someone has been in a "see no evil,
hear no evil, speak no evil" relationship with you from the get-go.


> Glenn is a troll.

Insults like this only make you look bad in the light of how irresponsibly you treated Glenn back in July.
I gave details about that in the following post, about an hour ago:

https://groups.google.com/g/sci.bio.paleontology/c/s4GvNGVaSWg/m/biZhrD-dBgAJ
Re: Where's Erik?

> Have you read anything he's
> posted in the past week or two?

Yes. He posted on this thread yesterday. Why aren't you showing any awareness that?

Could it be because he was NOT trolling?

>If that's your hope, maybe crossposting
> is a bad idea.
> > You are off to a bad start below by saying "you mean" when what I meant
> > was that Meyer did not claim that the Cambrian explosion
> > gave rise to animals that cannot be placed into extant phyla.

> > Your comment was ambiguous, and mean-spirited:

> What did he claim, then?

This question is so asinine, it makes you look like a troll. Meyer made
hundreds of claims in _Darwin's_Doubt_

> Wouldn't that claim, if he had made it, be correct?

Another asinine question. It obviously be incorrect to claim that a
creature of which we have fossils, didn't exist. Yet that's what you
wrote here seems to be saying:

> >>>> And these are all the animals Steven Meyer and the creationists claim
> >>>> don't exist.

You made all creationists sound omphalic with these clumsily chosen
words of yours.


Continued in next reply, to be done tomorrow, with some of the above
repeated for context.


Peter Nyikos

[Glenn]

Take his word for everything, he's smart.

" And he relegates potential
transitional fossils (Anomalocaris, Opabinia, halkieriids, etc.) either
to extant phyla or to new phyla, again unrelated to any others."

https://groups.google.com/g/talk.origins/c/Q6fpUBRFUjk/m/0hi862E9r_wJ

Let's see. "I forgot". Hmm, that might work. "That is not what I meant". Hmm, that might work. Which should I try first? Hmm. I could avoid the quote, and distract by focusing on another, perhaps by asking a question about something else. Hmm.

Take it from there, John. Oops, now that Glenn has posted the above, perhaps I should get real and say I was wrong. Nah... I could still claim "the creationists" claim such animals don't exist, and then associate Meyer with them...hey, great thought, eh John?

[Peter Nyikos]

So far, you've made a fine witness, Glenn. Keep up the good work.

> >
> > > Glenn is a troll.
> >
> > Insults like this only make you look bad in the light of how irresponsibly you treated Glenn back in July.
> > I gave details about that in the following post, about an hour ago:
> >
> > https://groups.google.com/g/sci.bio.paleontology/c/s4GvNGVaSWg/m/biZhrD-dBgAJ
> > Re: Where's Erik?

Most people in talk.origins seem to be allergic to clicking on links, and this may have affected
their behavior here in s.b.p.. I can think of two people whose antics certainly contributed
to that, both of them in good with John.

> > > Have you read anything he's posted in the past week or two?

> > Yes. He posted on this thread yesterday. Why aren't you showing any awareness that?
> >
> > Could it be because he was NOT trolling?

It will be interesting to see how John treats these questions.

> > >If that's your hope, maybe crossposting
> > > is a bad idea.
> > > > You are off to a bad start below by saying "you mean" when what I meant
> > > > was that Meyer did not claim that the Cambrian explosion
> > > > gave rise to animals that cannot be placed into extant phyla.
> > > > Your comment was ambiguous, and mean-spirited:

The comment is a few lines below, after some later exchanges.

> > > What did he claim, then?
> > This question is so asinine, it makes you look like a troll. Meyer made
> > hundreds of claims in _Darwin's_Doubt_
> > > Wouldn't that claim, if he had made it, be correct?
> > Another asinine question. It obviously be incorrect to claim that a
> > creature of which we have fossils, didn't exist. Yet that's what you
> > wrote here seems to be saying:

Here comes that comment:

> > > >>>> And these are all the animals Steven Meyer and the creationists claim
> > > >>>> don't exist.
> > You made all creationists sound omphalic with these clumsily chosen
> > words of yours.
> >
> Take his word for everything, he's smart.
>
> " And he relegates potential
> transitional fossils (Anomalocaris, Opabinia, halkieriids, etc.) either
> to extant phyla or to new phyla, again unrelated to any others."
>
> https://groups.google.com/g/talk.origins/c/Q6fpUBRFUjk/m/0hi862E9r_wJ

Re: Darwin's Doubt: a recycled thread

Excellent choice of quote, Glenn. It makes a nice counterpoint to some of what I
will be saying in my next installment of replies to John's post. I think there will be
three altogether; you are replying to the first one.

One problem, though: you evidently chose the wrong url. Here is the correct one,
to the OP of the thread [see subject line above]:
https://groups.google.com/g/talk.origins/c/Q6fpUBRFUjk/m/wmZK3yKR308J
Mar 5, 2014, 7:44:16 PM


By the way, thanks for that trip down memory lane. It's sad to see how many people
there were in 2014 whom I don't see any more. Dana Tweedy was one of
the best regulars we ever had. He kept Ray Martinez in check, and continued
to correct him for a while after Ray started to boycott him.

I don't miss Ray, but even he came up with some good comments here
and there. The following quote is appropriate to this thread:

"John has a doctorate in evolutionary biology, yet he cannot, with any specificity, describe Meyer's view of evolution. All John can say about Meyer is that "any significant amount of evolution is impossible"(see the OP)."
https://groups.google.com/g/talk.origins/c/Q6fpUBRFUjk/m/ZZgj7CzjMVMJ
Mar 6, 2014, 5:52:29 PM

Martinez went off the deep end in the rest of the post, but I rebutted John's quoted words here:
https://groups.google.com/g/talk.origins/c/Q6fpUBRFUjk/m/8IhpEpxaTk0J
Mar 10, 2014, 1:40:36 PM

> Let's see. "I forgot". Hmm, that might work. "That is not what I meant". Hmm, that might work. Which should I try first? Hmm. I could avoid the quote, and distract by focusing on another, perhaps by asking a question about something else. Hmm.
>
> Take it from there, John. Oops, now that Glenn has posted the above, perhaps I should get real and say I was wrong. Nah... I could still claim "the creationists" claim such animals don't exist, and then associate Meyer with them...hey, great thought, eh John?

I wonder how John will react to this. Some possibilities:

1. Your post, and this reply of mine, will join the multitude of
"posts that John can't see because he doesn't want to see them."

2. He will accuse you of trolling. However, my definition of trolling is "Making very provocative
statements that the utterer either knows to be false or doesn't give a hoot whether
any or all of them are false." You, on the other hand, are posting a rather realistic satire.

3. He will berate you for "detailing your various grievances." This is a standard way
he has of ignoring evidence of serious misbehavior by him or his buddies that I point out.


Peter Nyikos

[Peter Nyikos]

<snip of things dealt with in my first reply>

> >>>> And these are all the animals Steven Meyer and the creationists claim
> >>>> don't exist.

With the above for context, I pick up where I left off in my first reply.

> >>>
> >>> Meyer was well aware of Cambrian animals of problematic affinities,
> >>> including Wiwaxia, and also Amiskwia, Eldonia, and Nectocaris,
> >>> and took them in his stride.
> >

> >> [Your words] "in his stride" [remind me that] he ignored the fact that several of

> >> them contradicted his claim that there were no intermediates between phyla.

The bracketed parts replace incorrect words that made your statement literally false.
I believe they now make the statement true.

> >
> > That "fact" remains to be seen. Just what do you mean by "intermediates"?

Your explanation below makes it clear that you do not use the word
in any sense that is easily explainable to laymen. Meyer was writing
for a general audience, so he must have meant something else.

So I need to see what words of his you are [mis]interpreting above.

> > It would be anti-cladism heresy for you to claim that any of the groups that
> > Erik identified were paraphyletic, wouldn't it?

> No, it would not, but I don't claim such a thing anyway.
> > So, what did you mean, and where is your evidence?

> I suggest reading Budd G.E., Jensen S. A critical reappraisal of the
> fossil record of the bilaterian phyla. Biological Reviews 2000; 75:253-295.

If it does a MUCH better job of defining "intermediates" than you do below,
why didn't you simply quote its definition?

> Essentially, many Cambrian taxa are stem-members of their associated
> phyla and some of them are stem-members of groups of phyla.


> "Lobopods", for example, are stem-members of different ecdysozoan phyla.

Phyla are clades, so this would make "lobopods" a polyphyletic assemblage.
Might they be a "wastebasket taxon," like "Cotylosauria", "Thecodonta," "Insectivora," etc.?

> Halkieriids and/or tommotiids may (i.e., less certainly) be stem-lophotrochozoans.

IOW, they may be outside the crown group of all lophotrochozoans.
The following analogy comes to mind: the Sparassodonta, a clade which
includes the formidable saber-tooth Thylacosmilus, are stem-marsupials.
But no paleontologist would claim that they shed any light on the
relationship between marsupials and eutherians, or between the
various (crown) marsupial orders.

> > It would be anti-cladism heresy for you to claim that any of the groups that
> > Erik identified were paraphyletic, wouldn't it?

> No, it would not, but I don't claim such a thing anyway.

You may have to, if you can't improve on what you have done so far.

> >> But the part about ignoring them was that he ignored the small,
> >> shelly fauna that includes halkieriids and tommotiids, and that are
> >> precursors to the Cambrian explosion.
> >
> > I do recall an article about the "shellies" in a DI webpage, probably Evolution News,
> > where this omission was addressed.

> In what way was it addressed?

Maybe Glenn can help us out here. I am short on time today, likely shorter than you.

But the bottom line is, you are basing the "ignoring" on a book that may sparked the
intense interest in the "shellies" in the blogosphere. Do you disagree?

> > In any event, the sentence I quoted below puts these particular
> > shellies in the Cambrian:
> Yes, mostly, though a few are Precambrian.

You are obviously referring to something I did not quote. What is it?

> But the point is that they
> predate the visible explosion, i.e. the appearance of most phyla, which
> isn't until Cambrian Stage 3.

"the visible explosion" refers to what Meyer calls "the main pulse of the Cambrian explosion,"
rather than what he calls the explosion itself.

> >>> And the closing words of the abstract of the very paper you
> >>> are citing should have given you pause:
> >>>
> >>> "On this view, the absence of fossil Ediacaran sclerites is evidence against any ‘Precambrian prelude’ to the explosive diversification of these phyla in the Cambrian, c. 540–530 million years ago."

Note: NO precambrian exceptions, contrary to what you wrote above.

> >
> >> You will note that this places the beginning of the Cambrian explosion
> >> considerably before the time that Meyer attributes to it, in the
> >> Chengjiang fauna, and long before the fossil appearance of most phyla.
> >
> > I do not note any such thing. Meyer is very careful to note that "the Cambrian
> > explosion" has been given many different meanings by different people, and that he is primarily
> > concerned with what he calls "the main pulse" of the Cambrian explosion,
> > which lasted approximately 6 million years and saw the emergence of
> > 13 animal phyla in the fossil record by reckoning of Erwin et al.,
> > Science 334 (2011) 1091-97 and 16 animal phyla in a slightly different
> > ca. 6 my period by reckoning of Bowring et al, Science 261 (1993) 1293-98.

> What they're talking about there is Cambrian Stage 3, long after the
> rise of the small shellies. Meyer, and perhaps you also, is confused
> about the difference between the fossil record and the actual origins of taxa.

Correction: possibly Meyer, but it is a baseless insult to add "perhaps you also."

> The small shellies and the ichnofossil record are clues that the
> explosion is underway considerably before we get a good look at it. And
> also evidence that it was a gradual expansion.

I would not call "all fossilizable phyla in 40 million years" a gradual expansion,
given that some of the phyla seem to have gone extinct and NONE were added
in the subsequent 500+ million years.

You are a strange bedfellow of Donald Prothero, who nicknamed the Cambrian explosion
the "Cambrian slow fuse," claiming it took 80 million years.
I wrote some interesting things about him and you
last time around (see below), hence the "strange" in "strange bedfellow."


<snip of things to be dealt with tomorrow. I am short on time today>

> >> This explosive diversification they mention is not shown in the fossil
> >> record until Cambrian Stage 3, about 520 ma.
> >
> > What is your reference for this claim? It is inconsistent with what "they"
> > wrote and I quoted: "...c. 540–530 million years ago."

See the full quote above. It is NOT due to Erwin & Valentine, despite
what you say next:

> Try Erwin & Valentine.


<snip for focus>

> >>> Prothero might be turning in his grave, were he not still alive. :) :)
> >
> >> Whatever that means.
> >
> > You have a very leaky memory. Don't you remember how Prothero
> > wiped out all our comments and questions on his blog except your comment which
> > included the question of how he estimated 80 million years for what HE called
> > the Cambrian explosion? He left in his response which evaded the
> > question. When he saw how you politely pointed this out, he went on his rampage
> > of deleting about 40 questions and comments, including your polite pointing-out.


> I didn't know he had done that much,

You did know it, and you commented on it at the time. Another manifestation of
your leaky memory.

Seems you don't recall how you were barred from commenting anywhere in
the misnamed "Skepticblog," not just from that article by Prothero.

> but at any rate how would that be
> relevant to the present case?

See above about the 80 million "short fuse," which he also called the Cambrian explosion.

> Or did you just want to revive a grievance against him?

The real aggrieved party is Meyer, whose book Prothero flagrantly misrepresented,
including an out and out lie about what Meyer wrote about the 80 million period.

As for me, you and I have almost the same grievance as far as that mass censorship is concerned.
But his treatment of you was the more inexcusable of the two.

Peter Nyikos
Professor, Dept. of Mathematics -- standard disclaimer--

Univ. of South Carolina at Columbia
http://people.math.sc.edu/nyikos

[John Harshman]

Yes, that's a true statement. But what did you mean by "took them in his
stride"?

>>> That "fact" remains to be seen. Just what do you mean by "intermediates"?
>
> Your explanation below makes it clear that you do not use the word
> in any sense that is easily explainable to laymen. Meyer was writing
> for a general audience, so he must have meant something else.

What he meant was that all the modern phyla appeared fully formed in the
fossil record with no links or precursors. The "phylogenetic lawn" that
he talked about in the book. I don't see a reasonable sense of
"intermediate" that lets him off the hook for that claim.

> So I need to see what words of his you are [mis]interpreting above.

Again, I don't have the book available and so can't quote. But that was
his message.

>>> It would be anti-cladism heresy for you to claim that any of the groups that
>>> Erik identified were paraphyletic, wouldn't it?
>
>> No, it would not, but I don't claim such a thing anyway.
>>> So, what did you mean, and where is your evidence?
>
>> I suggest reading Budd G.E., Jensen S. A critical reappraisal of the
>> fossil record of the bilaterian phyla. Biological Reviews 2000; 75:253-295.
>
> If it does a MUCH better job of defining "intermediates" than you do below,
> why didn't you simply quote its definition?

I don't see the problem here. But I do recommend Budd & Jensen to anyone
interested in the Cambrian explosion.

>> Essentially, many Cambrian taxa are stem-members of their associated
>> phyla and some of them are stem-members of groups of phyla.
>
>> "Lobopods", for example, are stem-members of different ecdysozoan phyla.
>
> Phyla are clades, so this would make "lobopods" a polyphyletic assemblage.
> Might they be a "wastebasket taxon," like "Cotylosauria", "Thecodonta," "Insectivora," etc.?

No, just paraphyletic, just a bunch of Ecdysozoa outside the crown
groups of any of the current phyla. "Thecodonta" is, I believe, also
paraphyletic, being archosaurs outside varoius recognized clades (though
not just crown groups), while "Insectivora" is polyphyletic.

>> Halkieriids and/or tommotiids may (i.e., less certainly) be stem-lophotrochozoans.
>
> IOW, they may be outside the crown group of all lophotrochozoans.
> The following analogy comes to mind: the Sparassodonta, a clade which
> includes the formidable saber-tooth Thylacosmilus, are stem-marsupials.
> But no paleontologist would claim that they shed any light on the
> relationship between marsupials and eutherians, or between the
> various (crown) marsupial orders.

They might help, though, if they show what characters are primitive for
the clade. And of course they do show that there are precursors to the
various lophotrochozoan phyla, which is the main point.

>>> It would be anti-cladism heresy for you to claim that any of the groups that
>>> Erik identified were paraphyletic, wouldn't it?
>
>> No, it would not, but I don't claim such a thing anyway.
>
> You may have to, if you can't improve on what you have done so far.

Was that a useful comment?

>>>> But the part about ignoring them was that he ignored the small,
>>>> shelly fauna that includes halkieriids and tommotiids, and that are
>>>> precursors to the Cambrian explosion.
>>>
>>> I do recall an article about the "shellies" in a DI webpage, probably Evolution News,
>>> where this omission was addressed.
>
>> In what way was it addressed?
>
> Maybe Glenn can help us out here. I am short on time today, likely shorter than you.
>
> But the bottom line is, you are basing the "ignoring" on a book that may sparked the
> intense interest in the "shellies" in the blogosphere. Do you disagree?

I am unable to decipher that sentence. I am basing the "ignoring" on a
book that ignores the small shelly fauna. What relevance does a
hypothetical sparking of interest have to that? And I think I do
disagree. If anything sparked such interest, it wasn't the book but
various reviews of the book that pointed out the serious lapse.

>>> In any event, the sentence I quoted below puts these particular
>>> shellies in the Cambrian:
>> Yes, mostly, though a few are Precambrian.
>
> You are obviously referring to something I did not quote. What is it?

I am referring to the well-known Precambrian small shellies, notably
Cloudina and Namacalathus. By "a few" i referred to small shellies in
general, not the specific ones referred to in your quote.

>> But the point is that they
>> predate the visible explosion, i.e. the appearance of most phyla, which
>> isn't until Cambrian Stage 3.
>
> "the visible explosion" refers to what Meyer calls "the main pulse of the Cambrian explosion,"
> rather than what he calls the explosion itself.

True that the explosion expands and contracts throughout the book,
sometimes a tiny interval, sometimes the entire Cambrian.

>>>>> And the closing words of the abstract of the very paper you
>>>>> are citing should have given you pause:
>>>>>
>>>>> "On this view, the absence of fossil Ediacaran sclerites is evidence against any ‘Precambrian prelude’ to the explosive diversification of these phyla in the Cambrian, c. 540–530 million years ago."
>
> Note: NO precambrian exceptions, contrary to what you wrote above.

Yeah, that's technically right, as there are no Precambrian sclerites,
just whole shells. "These phyla" refers to mollusks, brachiopods, and
annelids, assuming that the earliest precursors of them were halkieriids
and tommotiids. But it's possible that there are precursors of those
groups that lacked scleritomes; one can certainly see many taxa without
readily preserved shells in the Chengjiang. And the scleritomes are not
the whole of the small shelly fauna.

Erik cited that, not me, by the way.

>>>> You will note that this places the beginning of the Cambrian explosion
>>>> considerably before the time that Meyer attributes to it, in the
>>>> Chengjiang fauna, and long before the fossil appearance of most phyla.
>>>
>>> I do not note any such thing. Meyer is very careful to note that "the Cambrian
>>> explosion" has been given many different meanings by different people, and that he is primarily
>>> concerned with what he calls "the main pulse" of the Cambrian explosion,
>>> which lasted approximately 6 million years and saw the emergence of
>>> 13 animal phyla in the fossil record by reckoning of Erwin et al.,
>>> Science 334 (2011) 1091-97 and 16 animal phyla in a slightly different
>>> ca. 6 my period by reckoning of Bowring et al, Science 261 (1993) 1293-98.
>
>> What they're talking about there is Cambrian Stage 3, long after the
>> rise of the small shellies. Meyer, and perhaps you also, is confused
>> about the difference between the fossil record and the actual origins of taxa.
>
> Correction: possibly Meyer, but it is a baseless insult to add "perhaps you also."

No insult intended. I'm glad you are not confused. But Meyer is.

>> The small shellies and the ichnofossil record are clues that the
>> explosion is underway considerably before we get a good look at it. And
>> also evidence that it was a gradual expansion.
>
> I would not call "all fossilizable phyla in 40 million years" a gradual expansion,
> given that some of the phyla seem to have gone extinct and NONE were added
> in the subsequent 500+ million years.

You don't know that. A good dozen phyla are not represented in the
Cambrian explosion, and some of them have no fossil record at all. The
first clear nematode fossil, for example, is Jurassic in age if I
recall, and that's probably the second most speciose animal phylum.

Anyway, how long does an event have to last in order to be considered
"gradual"? My point is that it took longer than Meyer is willing to
admit, and it was gradual at least in the sense that it didn't spring
full-blown in the fossil record but started small and expanded at a rate
sufficiently gradual for the expansion to be seen happening. Again, this
expansion is mostly in the diversity of ichnofossils and shelly fragments.

> You are a strange bedfellow of Donald Prothero, who nicknamed the Cambrian explosion
> the "Cambrian slow fuse," claiming it took 80 million years.
> I wrote some interesting things about him and you
> last time around (see below), hence the "strange" in "strange bedfellow."

I still can't imagine why you bring up Prothero.

>
> <snip of things to be dealt with tomorrow. I am short on time today>
>
>
>>>> This explosive diversification they mention is not shown in the fossil
>>>> record until Cambrian Stage 3, about 520 ma.
>>>
>>> What is your reference for this claim? It is inconsistent with what "they"
>>> wrote and I quoted: "...c. 540–530 million years ago."
>
> See the full quote above. It is NOT due to Erwin & Valentine, despite
> what you say next:
>
>> Try Erwin & Valentine.

I didn't say the quote above came from Erwin & Valentine. My point is
that Erwin & Valentine would give you a better understanding of the
timing of the explosion than that quote would. It a reference for my
claim about when the explosive diversification actually appears.

>>>>> Prothero might be turning in his grave, were he not still alive. :) :)
>>>
>>>> Whatever that means.
>>>
>>> You have a very leaky memory. Don't you remember how Prothero
>>> wiped out all our comments and questions on his blog except your comment which
>>> included the question of how he estimated 80 million years for what HE called
>>> the Cambrian explosion? He left in his response which evaded the
>>> question. When he saw how you politely pointed this out, he went on his rampage
>>> of deleting about 40 questions and comments, including your polite pointing-out.
>
>
>> I didn't know he had done that much,
>
> You did know it, and you commented on it at the time. Another manifestation of
> your leaky memory.
>
> Seems you don't recall how you were barred from commenting anywhere in
> the misnamed "Skepticblog," not just from that article by Prothero.

I do recall something of the sort. But why are we talking about it?

>> but at any rate how would that be
>> relevant to the present case?
>
> See above about the 80 million "short fuse," which he also called the Cambrian explosion.
>
>> Or did you just want to revive a grievance against him?
>
> The real aggrieved party is Meyer, whose book Prothero flagrantly misrepresented,
> including an out and out lie about what Meyer wrote about the 80 million period.
>
> As for me, you and I have almost the same grievance as far as that mass censorship is concerned.
> But his treatment of you was the more inexcusable of the two.

I am still mystified as to the point of talking about Prothero.

[erik simpson]

If you have actual interest in the "small shelly fauna" (pretty essential for anyone interested in "Cambrian explosion),
the Wiki entry for it is actually not a bad place to start. The SSF present quite a continuous (Ediacaran-Cambrian) record
of early stages of metazoan mineralization. It gives an extensive list of references, including (of course)
Budd et. al's excellent, if slightly dated review. if you are really suggesting that Meyer's book had anything to do with
"sparking interest" in this fossil record, that's truly ridiculous. Have you ever looked? It also appears you still have
not looked at Erwin & Valentine's book, which would be inexplicable for anyone interested in the subject.

[John Harshman]

You make a good point in passing that I would like to emphasize. We are
talking about the early stages of mineralization (and also, to some
extent, even just sclerotization), which may (almost certainly does,
considering the ichnofossil record) postdate the origins of the major
taxa whose mineralized skeletons we find. Taphonomy should be a major
consideration whenever you try to evaluate the fossil record.

[Peter Nyikos]

On Friday, September 30, 2022 at 11:02:23 AM UTC-4, erik simpson wrote:
> On Thursday, September 29, 2022 at 12:27:27 PM UTC-7, peter2...@gmail.com wrote:
> > On Wednesday, September 28, 2022 at 5:53:16 PM UTC-4, John Harshman wrote:
> > > On 9/28/22 2:32 PM, Peter Nyikos wrote:
> > > > On Tuesday, September 27, 2022 at 10:59:53 PM UTC-4, John Harshman wrote:
> > > >> On 9/27/22 6:31 PM, Peter Nyikos wrote:
> > > >
> > > >>> John's parting shot suggests that moving this thread to talk.origins
> > > >>> might generate a good deal of interest.
> > > >
> > > > You didn't comment on this. Do you disagree?
> > > Feel free to crosspost if you think so.
> > > >>> On Tuesday, September 27, 2022 at 6:43:30 PM UTC-4, John Harshman wrote:
> > > >>>> On 9/27/22 11:19 AM, erik simpson wrote:
> > > >>>>> On Tuesday, September 27, 2022 at 9:39:32 AM UTC-7, John Harshman wrote:
> > > >>>>>> On 9/27/22 9:22 AM, erik simpson wrote:
> > > >>>>>>> https://www.cell.com/current-biology/fulltext/S0960-9822(22)01455-5
> > > >>>>>>>
> > > >>>>>>> "Among extant animals, Lophotrochozoa accounts for the majority of phyla.1
> > > >>>>>>> This bilaterian clade radiated rapidly during the Cambrian explosion, obfuscating its phylogenetic relationships and rendering many aspects of its early evolution uncertain. Many early lophotrochozoans are known only from isolated skeletal microfossils, “small shelly fossils,” often derived from larger animals with complex multi-element skeletons.2

Compare this comment with the my PS at the end of my post.

> > > >>>>>>> The discovery of articulated fossils has revealed surprising insights into the animals from which these skeletal pieces were derived, such as paired shells in the mollusc Halkieria.3
> > > >>>>>>> Tommotiids are a key group of phosphatic early skeletal fossils that first appear in the late early Cambrian.4
> > > >>>>>>> ,5

And not during the Tommotian? See my comment about that near the end.

Hence my remark about Harshman's no-brainer reply to this
post of yours below, Erik.

I recall looking years ago, and if John does not come up with a better starting point, I'll take a look.

> It gives an extensive list of references, including (of course)
> Budd et. al's excellent, if slightly dated review. if you are really suggesting that Meyer's book had anything to do with
> "sparking interest" in this fossil record, that's truly ridiculous.

You left out "in the blogosphere" as opposed to the small number of professionals who had
reasons to be interested that were unrelated to the feeding frenzy that greeted Meyer's book.

Hence your "truly ridiculous" is disingenuous.

> Have you ever looked? It also appears you still have
> not looked at Erwin & Valentine's book,

Only to the top of Harshman's head from where he got that false idea, and to you blindly following him.
I bought a copy of their book for a close friend who is as widely interested in science
as myself, about 7 years ago, but I read it from cover to cover before leaving it with him.

Here is one thing that sticks in my mind: it said that the names "Tommotian" and "Atdabanian"
for the second and third stages of the Cambrian, of which Prothero childishly made
so much in his "review", were unworkable because they were based on Siberian strata
that cannot be coordinated with strata found elsewhere in the world.

Yet Prothero ALSO touted the Erwin and Valentine book to the high heavens
in the same "review." Go figure.

> which would be inexplicable for anyone interested in the subject.

Too bad for you that I am very interested, and too bad for John, with his
no-brainer reply to this post of yours.

Peter Nyikos
Professor, Dept. of Mathematics -- standard disclaimer--

University of South Carolina
http://people.math.sc.edu/nyikos

PS Did YOU read the Erwin & Valentine book? can you remember
whether it tried to assign any of the little shellies to various phyla?

[erik simpson]

And you left out that I said *IF* you are really suggesting...". As you acknowledge that
professionals (and interested amateurs) were unaffected by Meyer's work, I acknowledge
that you aren't suggesting that they were "sparked". Hence your accusation of my disingenuity

is disingenuous.

> > Have you ever looked? It also appears you still have
> > not looked at Erwin & Valentine's book,
> Only to the top of Harshman's head from where he got that false idea, and to you blindly following him.
> I bought a copy of their book for a close friend who is as widely interested in science
> as myself, about 7 years ago, but I read it from cover to cover before leaving it with him.
>
> Here is one thing that sticks in my mind: it said that the names "Tommotian" and "Atdabanian"
> for the second and third stages of the Cambrian, of which Prothero childishly made
> so much in his "review", were unworkable because they were based on Siberian strata
> that cannot be coordinated with strata found elsewhere in the world.
>
> Yet Prothero ALSO touted the Erwin and Valentine book to the high heavens
> in the same "review." Go figure.

I'm not familiar with Prothero's review, but E&V have a table correlating the various "stage names" that have
been used in the literature, not just for Laurentia and SIberia, but many other locations as well. There is no
current confusion.

> > which would be inexplicable for anyone interested in the subject.
> Too bad for you that I am very interested, and too bad for John, with his
> no-brainer reply to this post of yours.

Why is this "too bad" for me or anybody else? I'm glad you read it, but you've never said anything that I've
noticed that indicated familiarity with it. And judging form your remarks above, it still isn't obvious that
you're that familiar with it.

> Peter Nyikos
> Professor, Dept. of Mathematics -- standard disclaimer--
> University of South Carolina
> http://people.math.sc.edu/nyikos
> PS Did YOU read the Erwin & Valentine book? can you remember
> whether it tried to assign any of the little shellies to various phyla?

Very good. More disingenuous insults. Of course I've read it (parts several times), and of course they
suggest correspondence of the SSF:

"Although some of the SSFs are whole shells, such as thoseof tiny brachiopods, mollusks, and an array
of cones of uncertain affinities, others are individual plates, spines, and other skeletal elements that once
adorned larger animals and were preserved by the same phosphatization processes."
...
"The morphological diversity of early Cambrian small shelly sclerites suggest that they represent many different
clades, although lophotrochozoans are most commonly represented."

[Glenn]

Can the ancestry of various Cambrian phyla be resolved by a cladistic system of classification?

[erik simpson]

I'll take that as a genuine question, although I have doubt that's your intention. It depends on what you mean
by "ancestry" and "resolved". As to "ancestry" probably not, since "resolution" is very difficult. It's more likely
that "affinities" as in "X is more likely to be related to Y than to Z". This is frequently the case when the divisions
are very deep in time and happened during a period of rapid diversification. You can insome cases do better. for
example "Onychophorans are descended from lobopods" or "tardigrades are descended from lobopods" and "arthropods
are dscended from lobopods" are all generally accepted, but we can't identify which lobopods, nor whether each descended
from different lobopods, although the last is more likely. Would you consider that ancestry?

[Peter Nyikos]

I don't class that as a "disingenuous insult," in contrast to what you write about me below.

> > > > Peter Nyikos
> > > > Professor, Dept. of Mathematics -- standard disclaimer--
> > > > University of South Carolina
> > > > http://people.math.sc.edu/nyikos
> > > > PS Did YOU read the Erwin & Valentine book? can you remember
> > > > whether it tried to assign any of the little shellies to various phyla?

> > > Very good. More disingenuous insults.

This ridiculous charge needs to be compared and contrasted with your alleged
suspicions of Glenn asking his question below in bad faith.

Of course I've read it (parts several times), and of course they
> > > suggest correspondence of the SSF:
> > >
> > > "Although some of the SSFs are whole shells, such as thoseof tiny brachiopods, mollusks, and an array
> > > of cones of uncertain affinities, others are individual plates, spines, and other skeletal elements that once
> > > adorned larger animals and were preserved by the same phosphatization processes."
> > > ...
> > > "The morphological diversity of early Cambrian small shelly sclerites suggest that they represent many different
> > > clades, although lophotrochozoans are most commonly represented."

> > Can the ancestry of various Cambrian phyla be resolved by a cladistic system of classification?


> I'll take that as a genuine question, although I have doubt that's your intention.

I see no reason for taking it as anything but a genuine question.
Moreover, there is ample reason in Meyer's _Darwin's Doubt_ for you
to take it seriously on its own terms, regardless of what Glenn's
motivation might have been.

> It depends on what you mean
> by "ancestry" and "resolved". As to "ancestry" probably not, since "resolution" is very difficult.

Resolution is a nice goal to aim for, and it's a pity that no one seems to have
improved on your crude resolution below.

> It's more likely that "affinities" as in "X is more likely to be related to Y than to Z".

Ambiguous. Try substituting "Y is more likely to be the sister taxon of X than is Z"
and we will be getting somewhere.

>This is frequently the case when the divisions
> are very deep in time and happened during a period of rapid diversification. You can insome cases do better. for
> example "Onychophorans are descended from lobopods" or "tardigrades are descended from lobopods" and "arthropods
> are dscended from lobopods" are all generally accepted, but we can't identify which lobopods, nor whether each descended
> from different lobopods, although the last is more likely. Would you consider that ancestry?

I consider it a first step in the long road towards respecting paraphyletic taxa.
The next step would be to either try to narrow down the ancestry
or to try and find intermediates in the old-fashioned sense of the word.

For instance, old Reptilia was on the direct line of descent between
old Amphibia and old Aves. A big project of classical evolutionary systematics
[not to be confused with phylogenetic systematics] was to reduce the
size of intermediate taxa with the ultimate end of finding a species
or genus that was on a direct line of descent between two larger taxa.

Archaeopteryx, for example, was believed to be no more disparate
from a direct line of descent than some undiscovered fossil in the
same Linnean family. By abolishing such hypotheses, the victors
in the cladist wars set back the cause of understanding disparity
for at least two, perhaps three decades.

One of the casualties was the project of Van Valen to try and
narrow down the ancestry of the various ungulate orders [1]
and Cetacea [2] to families, and in some cases subfamilies
of what was then Condylartha.

[1] Including "subungulates" like Proboscidea, ancestry
tentatively hypothesized within Phenacolophidae.

[2] At the time, cetaceans were not recognized as artiodactyls.
Van Valen hypothesized their ancestry to be within the subfamily
Triisodontinae.

Other subfamilies with the same hypotheses:

Artiodactyla --- Oxyclaeninae

Perissodactyla -- Loxolophinae

All this can be found on pages 505-507 of Carroll's 1988
_Vertebrate Paleontology and Evolution_.


Naturally, we can't expect such refined results for lobopods,
but there are lots of hypotheses:

https://en.wikipedia.org/wiki/Lobopodia

Most notably, the various "stem groups" there may serve as proxies
for the forbidden paraphyletic taxa.

Peter Nyikos
Professor, Dept. of Mathematics -- standard disclaimer--

Univ. of South Carolina in Columbia
http://people.math.sc.edu/nyikos