Rocksolid Light

Welcome to novaBBS (click a section below)

mail  files  register  newsreader  groups  login

Message-ID:  

6 May, 2024: The networking issue during the past two days has been identified and fixed.


tech / sci.bio.paleontology / Re: Doushantuo-type biota in Laurentia

SubjectAuthor
* Doushantuo-type biota in Laurentiaerik simpson
`* Re: Doushantuo-type biota in LaurentiaPeter Nyikos
 `- Re: Doushantuo-type biota in Laurentiaerik simpson

1
Doushantuo-type biota in Laurentia

<bcc1918d-01d7-49a4-8b5a-b29daba0b325n@googlegroups.com>

  copy mid

https://www.novabbs.com/tech/article-flat.php?id=4756&group=sci.bio.paleontology#4756

  copy link   Newsgroups: sci.bio.paleontology
X-Received: by 2002:a05:620a:c47:b0:6cf:b0eb:3ac2 with SMTP id u7-20020a05620a0c4700b006cfb0eb3ac2mr12885549qki.511.1664769872306;
Sun, 02 Oct 2022 21:04:32 -0700 (PDT)
X-Received: by 2002:a25:d1d0:0:b0:6bd:cad:9354 with SMTP id
i199-20020a25d1d0000000b006bd0cad9354mr11585192ybg.454.1664769871841; Sun, 02
Oct 2022 21:04:31 -0700 (PDT)
Path: i2pn2.org!i2pn.org!usenet.blueworldhosting.com!feed1.usenet.blueworldhosting.com!peer03.iad!feed-me.highwinds-media.com!news.highwinds-media.com!news-out.google.com!nntp.google.com!postnews.google.com!google-groups.googlegroups.com!not-for-mail
Newsgroups: sci.bio.paleontology
Date: Sun, 2 Oct 2022 21:04:31 -0700 (PDT)
Injection-Info: google-groups.googlegroups.com; posting-host=72.34.122.133; posting-account=7D0teAoAAAB8rB1xAF_p12nmePXF7epT
NNTP-Posting-Host: 72.34.122.133
User-Agent: G2/1.0
MIME-Version: 1.0
Message-ID: <bcc1918d-01d7-49a4-8b5a-b29daba0b325n@googlegroups.com>
Subject: Doushantuo-type biota in Laurentia
From: eastside...@gmail.com (erik simpson)
Injection-Date: Mon, 03 Oct 2022 04:04:32 +0000
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
X-Received-Bytes: 2368
 by: erik simpson - Mon, 3 Oct 2022 04:04 UTC

Another item i'd missed, but of considerable interest to fans of the early Ediacaran:

https://www.nature.com/articles/s42003-020-01381-7

From the Conclusions:

"The Portfjeld Formation crops out over hundreds of kilometers in North Greenland but is poorly known on account of its remoteness. The assemblage of extremely well-preserved microfossils presented here, and its striking similarity to previously described fossils from the Doushantuo Formation of China, demonstrates greater complexity and worldwide distribution of the late Ediacaran ecosystem than previously recognized. The finds from North Greenland extend the known distribution of the Ediacaran Doushantuo-like biota along the length of the Pannotian palaeocontinent, from low to middle latitudes in the northern hemisphere (China) to the middle latitude position in the southern hemisphere occupied by North Greenland in eastern Laurentia; their age is confirmed by chemostratigraphy.

With a background in the largely unexplored potential represented by the Portfjeld Formation, the new discoveries offer excellent prospects for resolving the phylogenetic relationships of many of these problematic multicellular Ediacaran eukaryotes and a better understanding of the environments in which they evolved."

Re: Doushantuo-type biota in Laurentia

<8492a729-9411-4fa4-bd8d-7e422ca52623n@googlegroups.com>

  copy mid

https://www.novabbs.com/tech/article-flat.php?id=4758&group=sci.bio.paleontology#4758

  copy link   Newsgroups: sci.bio.paleontology
X-Received: by 2002:a05:620a:290d:b0:6b5:cecc:1cab with SMTP id m13-20020a05620a290d00b006b5cecc1cabmr14184969qkp.465.1664817916617;
Mon, 03 Oct 2022 10:25:16 -0700 (PDT)
X-Received: by 2002:a0d:c981:0:b0:330:dc03:7387 with SMTP id
l123-20020a0dc981000000b00330dc037387mr21084072ywd.380.1664817916399; Mon, 03
Oct 2022 10:25:16 -0700 (PDT)
Path: i2pn2.org!i2pn.org!usenet.blueworldhosting.com!feed1.usenet.blueworldhosting.com!peer02.iad!feed-me.highwinds-media.com!news.highwinds-media.com!news-out.google.com!nntp.google.com!postnews.google.com!google-groups.googlegroups.com!not-for-mail
Newsgroups: sci.bio.paleontology
Date: Mon, 3 Oct 2022 10:25:16 -0700 (PDT)
In-Reply-To: <bcc1918d-01d7-49a4-8b5a-b29daba0b325n@googlegroups.com>
Injection-Info: google-groups.googlegroups.com; posting-host=2600:1700:48c9:290:7925:7ce:cbf0:59c5;
posting-account=MmaSmwoAAABAWoWNw3B4MhJqLSp3_9Ze
NNTP-Posting-Host: 2600:1700:48c9:290:7925:7ce:cbf0:59c5
References: <bcc1918d-01d7-49a4-8b5a-b29daba0b325n@googlegroups.com>
User-Agent: G2/1.0
MIME-Version: 1.0
Message-ID: <8492a729-9411-4fa4-bd8d-7e422ca52623n@googlegroups.com>
Subject: Re: Doushantuo-type biota in Laurentia
From: peter2ny...@gmail.com (Peter Nyikos)
Injection-Date: Mon, 03 Oct 2022 17:25:16 +0000
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
X-Received-Bytes: 4781
 by: Peter Nyikos - Mon, 3 Oct 2022 17:25 UTC

On Monday, October 3, 2022 at 12:04:32 AM UTC-4, erik simpson wrote:
> Another item i'd missed, but of considerable interest to fans of the early Ediacaran:
>
> https://www.nature.com/articles/s42003-020-01381-7

> From the Conclusions:
>
> "The Portfjeld Formation crops out over hundreds of kilometers in North Greenland but is poorly known on account of its remoteness. The assemblage of extremely well-preserved microfossils presented here, and its striking similarity to previously described fossils from the Doushantuo Formation of China, demonstrates greater complexity and worldwide distribution of the late Ediacaran ecosystem than previously recognized. The finds from North Greenland extend the known distribution of the Ediacaran Doushantuo-like biota along the length of the Pannotian palaeocontinent, from low to middle latitudes in the northern hemisphere (China) to the middle latitude position in the southern hemisphere occupied by North Greenland in eastern Laurentia; their age is confirmed by chemostratigraphy.
>
> With a background in the largely unexplored potential represented by the Portfjeld Formation, the new discoveries offer excellent prospects for resolving the phylogenetic relationships of many of these problematic multicellular Ediacaran eukaryotes and a better understanding of the environments in which they evolved."

Note the "eukaryotes" in the last sentence.

It looks like one author was responsible for the conclusion and another for the abstract,
and neither bothered to read what the other wrote in the respective places.

From the Abstract:
"The Portfjeld biota consists of three-dimensionally preserved putative eggs and embryos, as well as acanthomorphic and leiosphaeric acritarchs, red algal thalli, sheet-like and oscillatoriacean cyanobacteria, and microbial mat fragments."

Cyanobacteria are prokaryotes; it would be astounding if the author of the "Conclusion" didn't know that.
Also, "microbial mats" could be composed partly or wholly of prokaryotes.

Also, "acritarchs" are a "wastebasket taxon" that could include prokaryotes:

"Acritarchs are organic microfossils, known from approximately 1800 million years ago to the present. The classification is a catch all term used to refer to any organic microfossils that cannot be assigned to other groups."
--https://en.wikipedia.org/wiki/Acritarch

Curiously, neither "acanthomorphic" nor "leiosphaeric" is in the above webpage,
but there are approximations there:
Acanthodiacrodium (Ordovician)
and
Leiosphaeridia (Cambrian-Silurian)

Thus it appears that the author of the abstract was going on superficial resemblances (phenetics?)
to justify his two terms. "acanthomorphic" seems to be well established (10 hits in the article)
but the only hit for "leiosphaeric" is the one I've quoted above.

One other immediate reaction:

The great majority of popular science on these fossils has been aimed at the hypothesis
that they are examples of animal embryos. Yet they could range over any number
of eukaryotic clades, and also prokaryotic.

For example, note the term "oscillatoriacean cyanobacteria" again.
*Oscillatoria* is a well known multicellular prokaryote
found in high school labs and biological supply companies.

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

Re: Doushantuo-type biota in Laurentia

<81187890-e5d2-4b68-b509-92c14c97941en@googlegroups.com>

  copy mid

https://www.novabbs.com/tech/article-flat.php?id=4761&group=sci.bio.paleontology#4761

  copy link   Newsgroups: sci.bio.paleontology
X-Received: by 2002:a05:6214:518c:b0:4b1:88f8:b6a4 with SMTP id kl12-20020a056214518c00b004b188f8b6a4mr6314839qvb.0.1664837245911;
Mon, 03 Oct 2022 15:47:25 -0700 (PDT)
X-Received: by 2002:a81:5209:0:b0:355:ce18:c0bb with SMTP id
g9-20020a815209000000b00355ce18c0bbmr18990195ywb.238.1664837245511; Mon, 03
Oct 2022 15:47:25 -0700 (PDT)
Path: i2pn2.org!i2pn.org!usenet.blueworldhosting.com!feed1.usenet.blueworldhosting.com!peer02.iad!feed-me.highwinds-media.com!news.highwinds-media.com!news-out.google.com!nntp.google.com!postnews.google.com!google-groups.googlegroups.com!not-for-mail
Newsgroups: sci.bio.paleontology
Date: Mon, 3 Oct 2022 15:47:25 -0700 (PDT)
In-Reply-To: <8492a729-9411-4fa4-bd8d-7e422ca52623n@googlegroups.com>
Injection-Info: google-groups.googlegroups.com; posting-host=72.34.122.133; posting-account=7D0teAoAAAB8rB1xAF_p12nmePXF7epT
NNTP-Posting-Host: 72.34.122.133
References: <bcc1918d-01d7-49a4-8b5a-b29daba0b325n@googlegroups.com> <8492a729-9411-4fa4-bd8d-7e422ca52623n@googlegroups.com>
User-Agent: G2/1.0
MIME-Version: 1.0
Message-ID: <81187890-e5d2-4b68-b509-92c14c97941en@googlegroups.com>
Subject: Re: Doushantuo-type biota in Laurentia
From: eastside...@gmail.com (erik simpson)
Injection-Date: Mon, 03 Oct 2022 22:47:25 +0000
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
X-Received-Bytes: 5613
 by: erik simpson - Mon, 3 Oct 2022 22:47 UTC

On Monday, October 3, 2022 at 10:25:17 AM UTC-7, peter2...@gmail.com wrote:
> On Monday, October 3, 2022 at 12:04:32 AM UTC-4, erik simpson wrote:
> > Another item i'd missed, but of considerable interest to fans of the early Ediacaran:
> >
> > https://www.nature.com/articles/s42003-020-01381-7
>
> > From the Conclusions:
> >
> > "The Portfjeld Formation crops out over hundreds of kilometers in North Greenland but is poorly known on account of its remoteness. The assemblage of extremely well-preserved microfossils presented here, and its striking similarity to previously described fossils from the Doushantuo Formation of China, demonstrates greater complexity and worldwide distribution of the late Ediacaran ecosystem than previously recognized. The finds from North Greenland extend the known distribution of the Ediacaran Doushantuo-like biota along the length of the Pannotian palaeocontinent, from low to middle latitudes in the northern hemisphere (China) to the middle latitude position in the southern hemisphere occupied by North Greenland in eastern Laurentia; their age is confirmed by chemostratigraphy.
> >
> > With a background in the largely unexplored potential represented by the Portfjeld Formation, the new discoveries offer excellent prospects for resolving the phylogenetic relationships of many of these problematic multicellular Ediacaran eukaryotes and a better understanding of the environments in which they evolved."
> Note the "eukaryotes" in the last sentence.
>
> It looks like one author was responsible for the conclusion and another for the abstract,
> and neither bothered to read what the other wrote in the respective places.
>
> From the Abstract:
> "The Portfjeld biota consists of three-dimensionally preserved putative eggs and embryos, as well as acanthomorphic and leiosphaeric acritarchs, red algal thalli, sheet-like and oscillatoriacean cyanobacteria, and microbial mat fragments."
>
> Cyanobacteria are prokaryotes; it would be astounding if the author of the "Conclusion" didn't know that.
> Also, "microbial mats" could be composed partly or wholly of prokaryotes.
>
> Also, "acritarchs" are a "wastebasket taxon" that could include prokaryotes:
>
> "Acritarchs are organic microfossils, known from approximately 1800 million years ago to the present. The classification is a catch all term used to refer to any organic microfossils that cannot be assigned to other groups."
> --https://en.wikipedia.org/wiki/Acritarch
>
> Curiously, neither "acanthomorphic" nor "leiosphaeric" is in the above webpage,
> but there are approximations there:
> Acanthodiacrodium (Ordovician)
> and
> Leiosphaeridia (Cambrian-Silurian)
>
> Thus it appears that the author of the abstract was going on superficial resemblances (phenetics?)
> to justify his two terms. "acanthomorphic" seems to be well established (10 hits in the article)
> but the only hit for "leiosphaeric" is the one I've quoted above.
>
>
> One other immediate reaction:
>
> The great majority of popular science on these fossils has been aimed at the hypothesis
> that they are examples of animal embryos. Yet they could range over any number
> of eukaryotic clades, and also prokaryotic.
>
> For example, note the term "oscillatoriacean cyanobacteria" again.
> *Oscillatoria* is a well known multicellular prokaryote
> found in high school labs and biological supply companies.
>
>
> Peter Nyikos
> Professor, Dept. of Mathematics -- standard disclaimer--
> University of South Carolina
> http://people.math.sc.edu/nyikos

The main point of this paper isn't to present any new insights into the phylogeny of this fossil assemblage. Those topics have
an extensive literature attached to the Doushantuo Formation. Controversy accompanies almost all of the suggestions. The
samples discussed in this paper were collected in 1978(!) and apparently not been described before, and are of considerable
interest in that they reveal that the Doushantuo conditions and biota represent a widely-distributed environment, and is in no
appreciable way unique.

1
server_pubkey.txt

rocksolid light 0.9.81
clearnet tor