All books on paleontology that go into detail about Ichthyosaurs agree that
they gave live birth: the fossil evidence for that is overwhelming.

The only ones I've found that discuss what happens before the live birth
are Romer's 1945 text, and Colbert's 1955 _Evolution_of_the_Vertebrates_,
which agree that they were ovoviviparous. Colbert writes:

So it is evident that these reptiles were ovoviviparous -- that they retained the egg within the body until it was hatched, as do some modern lizards and snakes. [*ibid*, p. 162]

In contrast, Carroll only has a photo of a fossil of an ichthyosaur giving live birth,
but no mention in the running text about it. The third edition of Benton's text
also makes no mention of the issue.

Wikipedia's entry simply claims they are viviparous and references an 1846
[NOT 1946] article by J.C. Pearce for it.

In a case of the left hand not knowing what the right hand is doing (and vice versa),
the entry on viviparity broadens the meaning of the term and distinguishes
four different varieties
among extant animals, giving examples of each kind. One of them is ovoviviparity,
which it seems to want to demote to a variety of oviparity.
https://en.wikipedia.org/wiki/Viviparity

Of course, it is difficult if not impossible to decide whether ichthyosaurs were
viviparous or ovoviviparous. It could even depend on the genera.
It is conceivable that some soft tissues could be found preserved in some
Konservat-Lagerstätten.
Either bits of fossilized egg membrane (or shell??) or something like an umbilical cord
could tip the scales heavily one way or the other.

Does anyone here have any ideas for other (probably much weaker)
evidence for one form or the other?

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

On 8/26/22 6:39 AM, Peter Nyikos wrote:
> All books on paleontology that go into detail about Ichthyosaurs agree that
> they gave live birth: the fossil evidence for that is overwhelming.
>
> The only ones I've found that discuss what happens before the live birth
> are Romer's 1945 text, and Colbert's 1955 _Evolution_of_the_Vertebrates_,
> which agree that they were ovoviviparous. Colbert writes:
>
> So it is evident that these reptiles were ovoviviparous -- that they retained the egg within the body until it was hatched, as do some modern lizards and snakes. [*ibid*, p. 162]
>
> In contrast, Carroll only has a photo of a fossil of an ichthyosaur giving live birth,
> but no mention in the running text about it. The third edition of Benton's text
> also makes no mention of the issue.
>
> Wikipedia's entry simply claims they are viviparous and references an 1846
> [NOT 1946] article by J.C. Pearce for it.
>
> In a case of the left hand not knowing what the right hand is doing (and vice versa),
> the entry on viviparity broadens the meaning of the term and distinguishes
> four different varieties
> among extant animals, giving examples of each kind. One of them is ovoviviparity,
> which it seems to want to demote to a variety of oviparity.
> https://en.wikipedia.org/wiki/Viviparity
>
>
> Of course, it is difficult if not impossible to decide whether ichthyosaurs were
> viviparous or ovoviviparous. It could even depend on the genera.
> It is conceivable that some soft tissues could be found preserved in some
> Konservat-Lagerstätten.
> Either bits of fossilized egg membrane (or shell??) or something like an umbilical cord
> could tip the scales heavily one way or the other.
>
>
> Does anyone here have any ideas for other (probably much weaker)
> evidence for one form or the other?

It seems unlikely that any sort of evidence could be preserved. It also
seems unlikely that an ovoviviparous ichthyosaur would have hard-shelled
eggs. Whatever evidence did Romer use for his claim? Phylogenetic
bracketing, perhaps?

On Friday, August 26, 2022 at 6:39:46 AM UTC-7, peter2...@gmail.com wrote:
> All books on paleontology that go into detail about Ichthyosaurs agree that
> they gave live birth: the fossil evidence for that is overwhelming.
>
> The only ones I've found that discuss what happens before the live birth
> are Romer's 1945 text, and Colbert's 1955 _Evolution_of_the_Vertebrates_,
> which agree that they were ovoviviparous. Colbert writes:
>
> So it is evident that these reptiles were ovoviviparous -- that they retained the egg within the body until it was hatched, as do some modern lizards and snakes. [*ibid*, p. 162]
>
> In contrast, Carroll only has a photo of a fossil of an ichthyosaur giving live birth,
> but no mention in the running text about it. The third edition of Benton's text
> also makes no mention of the issue.
>
> Wikipedia's entry simply claims they are viviparous and references an 1846
> [NOT 1946] article by J.C. Pearce for it.
>
> In a case of the left hand not knowing what the right hand is doing (and vice versa),
> the entry on viviparity broadens the meaning of the term and distinguishes
> four different varieties
> among extant animals, giving examples of each kind. One of them is ovoviviparity,
> which it seems to want to demote to a variety of oviparity.
> https://en.wikipedia.org/wiki/Viviparity
>
>
> Of course, it is difficult if not impossible to decide whether ichthyosaurs were
> viviparous or ovoviviparous. It could even depend on the genera.
> It is conceivable that some soft tissues could be found preserved in some
> Konservat-Lagerstätten.
> Either bits of fossilized egg membrane (or shell??) or something like an umbilical cord
> could tip the scales heavily one way or the other.
>
>
> Does anyone here have any ideas for other (probably much weaker)
> evidence for one form or the other?
>
>
> Peter Nyikos
> Professor, Dept. of Mathematics -- standard disclaimer--
> University of South Carolina
> http://people.math.sc.edu/nyikos

Evidence for viviparity in ichthyosaurs having appeared in land-living ancestors:

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0088640
https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0088640&type=printable (open access)

On Friday, August 26, 2022 at 11:37:49 AM UTC-4, erik simpson wrote:
> On Friday, August 26, 2022 at 6:39:46 AM UTC-7, peter2...@gmail.com wrote:
> > All books on paleontology that go into detail about Ichthyosaurs agree that
> > they gave live birth: the fossil evidence for that is overwhelming.
> >
> > The only ones I've found that discuss what happens before the live birth
> > are Romer's 1945 text, and Colbert's 1955 _Evolution_of_the_Vertebrates_,
> > which agree that they were ovoviviparous. Colbert writes:
> >
> > So it is evident that these reptiles were ovoviviparous -- that they retained the egg within the body until it was hatched, as do some modern lizards and snakes. [*ibid*, p. 162]
> >
> > In contrast, Carroll [1988] only has a photo of a fossil of an ichthyosaur giving live birth,
> > but no mention in the running text about it. The third edition of Benton's text
> > also makes no mention of the issue.
> >
> > Wikipedia's entry simply claims they are viviparous and references an 1846
> > [NOT 1946] article by J.C. Pearce for it.
> >
> > In a case of the left hand not knowing what the right hand is doing (and vice versa),
> > the entry on viviparity broadens the meaning of the term and distinguishes
> > four different varieties
> > among extant animals, giving examples of each kind. One of them is ovoviviparity,
> > which it seems to want to demote to a variety of oviparity.
> > https://en.wikipedia.org/wiki/Viviparity
> >
> >
> > Of course, it is difficult if not impossible to decide whether ichthyosaurs were
> > viviparous or ovoviviparous. It could even depend on the genera.
> > It is conceivable that some soft tissues could be found preserved in some
> > Konservat-Lagerstätten.
> > Either bits of fossilized egg membrane (or shell??) or something like an umbilical cord
> > could tip the scales heavily one way or the other.
> >
> >
> > Does anyone here have any ideas for other (probably much weaker)
> > evidence for one form or the other?
> >
> >
> > Peter Nyikos
> > Professor, Dept. of Mathematics -- standard disclaimer--
> > University of South Carolina
> > http://people.math.sc.edu/nyikos
> Evidence for viviparity in ichthyosaurs having appeared in land-living ancestors:
>
> https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0088640
> https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0088640&type=printable (open access)

Two copies of the same article, as far as I could tell.

Unfortunately, the authors' argument for viviparity is very weak.
The following seems to be as close as they try to come:

Viviparity in extant reptiles is known only among squamates. Despite the traditional four-step evolutionary model from lecithotrophy to placentotrophy, squamate reproductive strategies are almost bimodally divided between oviparity (egg laying), including cases of egg retention up to limb-bud stage, and viviparity involving functional placentation [2], with few intermediate forms [22]. Therefore, viviparity seems to evolve simultaneously with functional placentation in squamates [23]. Given these observations, it would be reasonable if viviparity in Chaohusaurus involved a degree of placentation. However, this inference cannot be tested directly with fossil evidence because the soft tissue is not preserved.

[22] is linked to a mere abstract via Google Scholar, while "View Article" just takes us back
to the article itself! The same goes for [23].

My time today for posting is limited, so for the moment I have to fall back on Wikipedia,
specifically the link I gave earlier, https://en.wikipedia.org/wiki/Viviparity and the following:

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

Unfortunately, this gives no reptilian examples, while the other website only has this:

"Ovoviviparity, a less developed form of viviparity, occurs in most vipers, and in most live-bearing bony fishes (Poeciliidae)."

There is a link for "vipers," but its talk of their reproduction only takes us back to
https://en.wikipedia.org/wiki/Viviparity

Looks like we need to borrow a term from chess for this kind of frustration:

"Draw by perpetual check" :)

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

On Friday, August 26, 2022 at 9:49:20 AM UTC-7, peter2...@gmail.com wrote:
> On Friday, August 26, 2022 at 11:37:49 AM UTC-4, erik simpson wrote:
> > On Friday, August 26, 2022 at 6:39:46 AM UTC-7, peter2...@gmail.com wrote:
> > > All books on paleontology that go into detail about Ichthyosaurs agree that
> > > they gave live birth: the fossil evidence for that is overwhelming.
> > >
> > > The only ones I've found that discuss what happens before the live birth
> > > are Romer's 1945 text, and Colbert's 1955 _Evolution_of_the_Vertebrates_,
> > > which agree that they were ovoviviparous. Colbert writes:
> > >
> > > So it is evident that these reptiles were ovoviviparous -- that they retained the egg within the body until it was hatched, as do some modern lizards and snakes. [*ibid*, p. 162]
> > >
> > > In contrast, Carroll [1988] only has a photo of a fossil of an ichthyosaur giving live birth,
> > > but no mention in the running text about it. The third edition of Benton's text
> > > also makes no mention of the issue.
> > >
> > > Wikipedia's entry simply claims they are viviparous and references an 1846
> > > [NOT 1946] article by J.C. Pearce for it.
> > >
> > > In a case of the left hand not knowing what the right hand is doing (and vice versa),
> > > the entry on viviparity broadens the meaning of the term and distinguishes
> > > four different varieties
> > > among extant animals, giving examples of each kind. One of them is ovoviviparity,
> > > which it seems to want to demote to a variety of oviparity.
> > > https://en.wikipedia.org/wiki/Viviparity
> > >
> > >
> > > Of course, it is difficult if not impossible to decide whether ichthyosaurs were
> > > viviparous or ovoviviparous. It could even depend on the genera.
> > > It is conceivable that some soft tissues could be found preserved in some
> > > Konservat-Lagerstätten.
> > > Either bits of fossilized egg membrane (or shell??) or something like an umbilical cord
> > > could tip the scales heavily one way or the other.
> > >
> > >
> > > Does anyone here have any ideas for other (probably much weaker)
> > > evidence for one form or the other?
> > >
> > >
> > > Peter Nyikos
> > > Professor, Dept. of Mathematics -- standard disclaimer--
> > > University of South Carolina
> > > http://people.math.sc.edu/nyikos
> > Evidence for viviparity in ichthyosaurs having appeared in land-living ancestors:
> >
> > https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0088640
> > https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0088640&type=printable (open access)
> Two copies of the same article, as far as I could tell.
>
> Unfortunately, the authors' argument for viviparity is very weak.
> The following seems to be as close as they try to come:
>
> Viviparity in extant reptiles is known only among squamates. Despite the traditional four-step evolutionary model from lecithotrophy to placentotrophy, squamate reproductive strategies are almost bimodally divided between oviparity (egg laying), including cases of egg retention up to limb-bud stage, and viviparity involving functional placentation [2], with few intermediate forms [22]. Therefore, viviparity seems to evolve simultaneously with functional placentation in squamates [23]. Given these observations, it would be reasonable if viviparity in Chaohusaurus involved a degree of placentation. However, this inference cannot be tested directly with fossil evidence because the soft tissue is not preserved.
>
> [22] is linked to a mere abstract via Google Scholar, while "View Article" just takes us back
> to the article itself! The same goes for [23].
>
> My time today for posting is limited, so for the moment I have to fall back on Wikipedia,
> specifically the link I gave earlier, https://en.wikipedia.org/wiki/Viviparity and the following:
>
> https://en.wikipedia.org/wiki/Ovoviviparity
>
> Unfortunately, this gives no reptilian examples, while the other website only has this:
>
> "Ovoviviparity, a less developed form of viviparity, occurs in most vipers, and in most live-bearing bony fishes (Poeciliidae)."
>
> There is a link for "vipers," but its talk of their reproduction only takes us back to
> https://en.wikipedia.org/wiki/Viviparity
>
>
> Looks like we need to borrow a term from chess for this kind of frustration:
>
> "Draw by perpetual check" :)
> Peter Nyikos
> Professor, Dept. of Mathematics -- standard disclaimer--
> Univ. of South Carolina at Columbia
> http://people.math.sc.edu/nyikos

I knew I'd seen something about this and I found the paper in my collection of PDFs. Checking online, it's
still there as I cited. Both cite are the same, one (potentially?) paywalled.

From the paper "squamate reproductive strategies are almost bimodally divided between oviparity (egg laying), including
cases of egg retention up to limb-bud stage, and viviparity involving functional placentation, with few
intermediate forms." (Refences cited in the paper)

The Wiki entry does suggest caution with the use of the term ovoviviparity as "poorly and inconsistently defined, and may be obsolete.
This term has been redefined and more commonly referred to as oviparous egg retention or prolonged egg retention."

So yeah, ichthyosaurs aren't squamates, and there's no evidence of egg retention, but I don't see any need to
be frustrated. Again, from the paper: "Given these observations, it would be reasonable if viviparity in Chaohusaurus
involved a degree of placentation. However, this inference cannot be tested directly with fossil evidence because the
soft tissue is not preserved."

I've found myself with a bit of unexpected free time, but even so,
this might be my last post to s.b.p. until Monday.

On Friday, August 26, 2022 at 4:33:43 PM UTC-4, erik simpson wrote:
> On Friday, August 26, 2022 at 9:49:20 AM UTC-7, peter2...@gmail.com wrote:
> > On Friday, August 26, 2022 at 11:37:49 AM UTC-4, erik simpson wrote:
> > > On Friday, August 26, 2022 at 6:39:46 AM UTC-7, peter2...@gmail.com wrote:
> > > > All books on paleontology that go into detail about Ichthyosaurs agree that
> > > > they gave live birth: the fossil evidence for that is overwhelming.
> > > >
> > > > The only ones I've found that discuss what happens before the live birth
> > > > are Romer's 1945 text, and Colbert's 1955 _Evolution_of_the_Vertebrates_,
> > > > which agree that they were ovoviviparous. Colbert writes:
> > > >
> > > > So it is evident that these reptiles were ovoviviparous -- that they retained the egg within the body until it was hatched, as do some modern lizards and snakes. [*ibid*, p. 162]
> > > >
> > > > In contrast, Carroll [1988] only has a photo of a fossil of an ichthyosaur giving live birth,
> > > > but no mention in the running text about it. The third edition of Benton's text
> > > > also makes no mention of the issue.
> > > >
> > > > Wikipedia's entry simply claims they are viviparous and references an 1846
> > > > [NOT 1946] article by J.C. Pearce for it.
> > > >
> > > > In a case of the left hand not knowing what the right hand is doing (and vice versa),
> > > > the entry on viviparity broadens the meaning of the term and distinguishes
> > > > four different varieties
> > > > among extant animals, giving examples of each kind. One of them is ovoviviparity,
> > > > which it seems to want to demote to a variety of oviparity.
> > > > https://en.wikipedia.org/wiki/Viviparity
> > > >
> > > >
> > > > Of course, it is difficult if not impossible to decide whether ichthyosaurs were
> > > > viviparous or ovoviviparous. It could even depend on the genera.
> > > > It is conceivable that some soft tissues could be found preserved in some
> > > > Konservat-Lagerstätten.
> > > > Either bits of fossilized egg membrane (or shell??) or something like an umbilical cord
> > > > could tip the scales heavily one way or the other.
> > > >
> > > >
> > > > Does anyone here have any ideas for other (probably much weaker)
> > > > evidence for one form or the other?
> > > >
> > > >
> > > > Peter Nyikos
> > > > Professor, Dept. of Mathematics -- standard disclaimer--
> > > > University of South Carolina
> > > > http://people.math.sc.edu/nyikos
> > > Evidence for viviparity in ichthyosaurs having appeared in land-living ancestors:
> > >
> > > https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0088640
> > > https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0088640&type=printable (open access)
> > Two copies of the same article, as far as I could tell.
> >
> > Unfortunately, the authors' argument for viviparity is very weak.
> > The following seems to be as close as they try to come:

In your reply, Erik, you are repeating two subsets of what is in the following paragraph.

> > Viviparity in extant reptiles is known only among squamates. Despite the traditional four-step evolutionary model from lecithotrophy to placentotrophy, squamate reproductive strategies are almost bimodally divided between oviparity (egg laying), including cases of egg retention up to limb-bud stage, and viviparity involving functional placentation [2], with few intermediate forms [22]. Therefore, viviparity seems to evolve simultaneously with functional placentation in squamates [23]. Given these observations, it would be reasonable if viviparity in Chaohusaurus involved a degree of placentation. However, this inference cannot be tested directly with fossil evidence because the soft tissue is not preserved.
> >
> > [22] is linked to a mere abstract via Google Scholar, while "View Article" just takes us back
> > to the article itself! The same goes for [23].
> >
> > My time today for posting is limited, so for the moment I have to fall back on Wikipedia,
> > specifically the link I gave earlier, https://en.wikipedia.org/wiki/Viviparity and the following:
> >
> > https://en.wikipedia.org/wiki/Ovoviviparity
> >
> > Unfortunately, this gives no reptilian examples, while the other website only has this:
> >
> > "Ovoviviparity, a less developed form of viviparity, occurs in most vipers, and in most live-bearing bony fishes (Poeciliidae)."

The frustration I talk about below is inability to find out whether some vipers
are viviparous and others are ovoviviparous.

> >
> > There is a link for "vipers," but its talk of their reproduction only takes us back to
> > https://en.wikipedia.org/wiki/Viviparity
> >
> >
> > Looks like we need to borrow a term from chess for this kind of frustration:
> >
> > "Draw by perpetual check" :)

> I knew I'd seen something about this and I found the paper in my collection of PDFs. Checking online, it's
> still there as I cited. Both cite are the same, one (potentially?) paywalled.
>
> From the paper "squamate reproductive strategies are almost bimodally divided between oviparity (egg laying), including
> cases of egg retention up to limb-bud stage, and viviparity involving functional placentation, with few
> intermediate forms." (Refences cited in the paper)

This is the first subset that I mentioned above.

>
> The Wiki entry does suggest caution with the use of the term ovoviviparity as "poorly and inconsistently defined, and may be obsolete.
> This term has been redefined and more commonly referred to as oviparous egg retention or prolonged egg retention."

With reptiles there does not seem to be any problem, because AFAIK the live offspring are miniatures
[roughly speaking, like with us humans] of their parents.

Not so with mammals, though: marsupials and even some placentals have their live births in a stage
like the late embryo or early fetus of humans.

A similar problem comes with amphibians, whether the live birth is of the larval or of the adult form. Both forms are found:

The young of some ovoviviparous amphibians, such as Limnonectes larvaepartus, are born as larvae, and undergo further metamorphosis outside the body of the mother. Members of genera Nectophrynoides and Eleutherodactylus bear froglets, not only the hatching, but all the most conspicuous metamorphosis, being completed inside the body of the mother before birth.
-- https://en.wikipedia.org/wiki/Ovoviviparity

>
> So yeah, ichthyosaurs aren't squamates, and there's no evidence of egg retention,

....the alternatives being the following:

Histotrophic viviparity: the zygotes develop in the female's oviducts, but find their nutriments by oophagy or adelphophagy (intra-uterine cannibalism of eggs or sibling embryos in some sharks or in the black salamander Salamandra atra).
Hemotrophic viviparity: nutrients are provided by the female, often through some form of placenta. In the frog Gastrotheca ovifera, embryos are fed by the mother through specialized gills. The skink Pseudemoia entrecasteauxii and most mammals exhibit a hemotrophic viviparity.
Placental viviparity is arguably the most highly developed form of viviparity. Placental mammals, including humans, are the best-known example, but adaptations in some other animals also have incorporated this principle or close analogies. Other examples include some species of scorpions[5] and cockroaches,[6][7] certain genera of sharks and snakes, and velvet worms.
https://en.wikipedia.org/wiki/Viviparity

More frustration: I have no clue as to where the author draws the line between Hemotrophic viviparity and Placental viviparity.
There is a link for the latter -- just click on "Placental viviparity" -- but it is utterly useless for that purpose:

"Placentas are a defining characteristic of placental mammals, but are also found in marsupials"
https://en.wikipedia.org/wiki/Placenta
....which strongly contradicts "most mammals exhibit a hemotrophic viviparity." [See above.]

Now, I've known about many different kinds of mammalian placentas for decades,
with varying degrees of inte]rpenetration and whether they are choriovitelline [marsupials]
or chorioallantoic [most placentals but NOT primates, where the allantois is vestigial]
and this heightens my frustration.

> but I don't see any need to be frustrated. Again, from the paper: "Given these observations, it would be reasonable if viviparity in Chaohusaurus
> involved a degree of placentation. However, this inference cannot be tested directly with fossil evidence because the
> soft tissue is not preserved."

On Friday, August 26, 2022 at 6:32:49 PM UTC-4, Peter Nyikos wrote:

> You aren't contributing anything to the on-topic discussion in this second post of yours, Erik.

Minor technical exception: you completed the three-line description of Ovoviviparity in
https://en.wikipedia.org/wiki/Viviparity
of which I had posted the first sentence.

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

Wasn’t there something about reptile eggs needing to breathe or something? I supose amphibian eggs can be underwater; are reptile eggs the same way?

On Friday, August 26, 2022 at 3:42:40 PM UTC-7, peter2...@gmail.com wrote:
> On Friday, August 26, 2022 at 6:32:49 PM UTC-4, Peter Nyikos wrote:
>
> > You aren't contributing anything to the on-topic discussion in this second post of yours, Erik.
> Minor technical exception: you completed the three-line description of Ovoviviparity in
> https://en.wikipedia.org/wiki/Viviparity
> of which I had posted the first sentence.
> > Peter Nyikos
> > Professor, Dept. of Mathematics -- standard disclaimer--
> > Univ. of South Carolina in Columbia
> > http://people.math.sc.edu/nyikos

You're contributing what I see as a substantial digression into Mammalia. As for vipers, "squamate reproductive
strategies are almost bimodally divided between oviparity (egg laying), including cases of egg retention up to limb-bud stage,
and viviparity involving functional placentation". I don't understand what's frustrating.

On Friday, August 26, 2022 at 3:47:42 PM UTC-7, thesigh...@gmail.com wrote:
> Wasn’t there something about reptile eggs needing to breathe or something? I supose amphibian eggs can be underwater; are reptile eggs the same way?

Once laid, eggs certainly do need to breathe (egg shells allow for this). I'm not sure what goes on in "retained" eggs.

On Friday, August 26, 2022 at 7:16:18 PM UTC-4, erik simpson wrote:
> On Friday, August 26, 2022 at 3:42:40 PM UTC-7, peter2...@gmail.com wrote:
> > On Friday, August 26, 2022 at 6:32:49 PM UTC-4, Peter Nyikos wrote:
> >
> > > You aren't contributing anything to the on-topic discussion in this second post of yours, Erik.

> > Minor technical exception: you completed the three-line description of Ovoviviparity in
> > https://en.wikipedia.org/wiki/Viviparity
> > of which I had posted the first sentence.

> You're contributing what I see as a substantial digression into Mammalia. As for vipers, "squamate reproductive
> strategies are almost bimodally divided between oviparity (egg laying), including cases of egg retention up to limb-bud stage,
> and viviparity involving functional placentation". I don't understand what's frustrating.

The fact that the claim could be wrong [see reasoning below], and thus being used fallaciously to support
viviparity in ichthyosaurs, which is at the exact resonant center of this thread.

I guess the shortness of the post attracted you like a magnet, causing you
to miss out on the original post, including the following reasoning:

___________________________ first excerpt from the original post_________________

> but I don't see any need to be frustrated. Again, from the paper: "Given these observations, it would be reasonable if viviparity in Chaohusaurus
> involved a degree of placentation. However, this inference cannot be tested directly with fossil evidence because the
> soft tissue is not preserved."

This is the second subset of what I quoted, and is why I find vipers so frustrating.
For all I know, they might be mostly viviparous [which would make the inference "reasonable"]
or all ovoviviparous [which would make the inference almost untenable, given the variety of vipers].

======================== end of first excerpt =======================

And here is why the "Given" is seriously affected:

######################## second excerpt from the original post #####################

> From the paper "squamate reproductive strategies are almost bimodally divided between oviparity (egg laying), including
> cases of egg retention up to limb-bud stage, and viviparity involving functional placentation, with few
> intermediate forms." (Refences cited in the paper)

This is the first subset that I mentioned above.

************************************************************ end of second excerpt
from
https://groups.google.com/g/sci.bio.paleontology/c/X2eRy1wQf8U/m/4I_chwJ8AQAJ
Re: Were Ichthyosaurs Ovoviviparous, or Viviparous?

And, lest your memory fail you between the first repost and the second, compare:

"make the inference almost untenable, given the variety of vipers".
and
> "almost bimodally, ... with few intermediate forms."

Capice?

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

On 8/26/22 5:12 PM, Peter Nyikos wrote:
> On Friday, August 26, 2022 at 7:16:18 PM UTC-4, erik simpson wrote:
>> On Friday, August 26, 2022 at 3:42:40 PM UTC-7, peter2...@gmail.com wrote:
>>> On Friday, August 26, 2022 at 6:32:49 PM UTC-4, Peter Nyikos wrote:
>>>
>>>> You aren't contributing anything to the on-topic discussion in this second post of yours, Erik.
>
>>> Minor technical exception: you completed the three-line description of Ovoviviparity in
>>> https://en.wikipedia.org/wiki/Viviparity
>>> of which I had posted the first sentence.
>
>> You're contributing what I see as a substantial digression into Mammalia. As for vipers, "squamate reproductive
>> strategies are almost bimodally divided between oviparity (egg laying), including cases of egg retention up to limb-bud stage,
>> and viviparity involving functional placentation". I don't understand what's frustrating.
>
> The fact that the claim could be wrong [see reasoning below], and thus being used fallaciously to support
> viviparity in ichthyosaurs, which is at the exact resonant center of this thread.

If you want to find about whether the claims in that paper are wrong,
you should consult the references cited to support the claims. In this
case that would seem to be references 2 and 22.

> I guess the shortness of the post attracted you like a magnet, causing you
> to miss out on the original post, including the following reasoning:
>
> ___________________________ first excerpt from the original post_________________
>
>> but I don't see any need to be frustrated. Again, from the paper: "Given these observations, it would be reasonable if viviparity in Chaohusaurus
>> involved a degree of placentation. However, this inference cannot be tested directly with fossil evidence because the
>> soft tissue is not preserved."
>
> This is the second subset of what I quoted, and is why I find vipers so frustrating.
> For all I know, they might be mostly viviparous [which would make the inference "reasonable"]
> or all ovoviviparous [which would make the inference almost untenable, given the variety of vipers].

Apparently, "ovoviviparous" is ambiguous and not a useful term.
Apparently, retention of the eggs until hatching (or birth, if you
prefer) requires maternal nourishment of the eggs, at least in squamates.

> ======================== end of first excerpt =======================
>
> And here is why the "Given" is seriously affected:
>
> ######################## second excerpt from the original post #####################
>
>> From the paper "squamate reproductive strategies are almost bimodally divided between oviparity (egg laying), including
>> cases of egg retention up to limb-bud stage, and viviparity involving functional placentation, with few
>> intermediate forms." (Refences cited in the paper)
>
> This is the first subset that I mentioned above.
>
> ************************************************************ end of second excerpt
> from
> https://groups.google.com/g/sci.bio.paleontology/c/X2eRy1wQf8U/m/4I_chwJ8AQAJ
> Re: Were Ichthyosaurs Ovoviviparous, or Viviparous?
>
> And, lest your memory fail you between the first repost and the second, compare:
>
> "make the inference almost untenable, given the variety of vipers".
> and
>> "almost bimodally, ... with few intermediate forms."

The second quote would seem to entail that the first quote is wrong.
Have you tried looking at the cited references? Have you searched for a
review of squamate viviparity?

Here's one: https://rep.bioscientifica.com/view/journals/rep/147/1/R15.xml

Abstract: Squamate reptiles (lizards and snakes) are an ideal model
system for testing hypotheses regarding the evolution of viviparity
(live birth) in amniote vertebrates. Viviparity has evolved over 100
times in squamates, resulting in major changes in reproductive
physiology. At a minimum, all viviparous squamates exhibit placentae
formed by the appositions of maternal and embryonic tissues, which are
homologous in origin with the tissues that form the placenta in therian
mammals. These placentae facilitate adhesion of the conceptus to the
uterus as well as exchange of oxygen, carbon dioxide, water, sodium, and
calcium. However, most viviparous squamates continue to rely on yolk for
nearly all of their organic nutrition. In contrast, some species, which
rely on the placenta for at least a portion of organic nutrition,
exhibit complex placental specializations associated with the transport
of amino acids and fatty acids. Some viviparous squamates also exhibit
reduced immunocompetence during pregnancy, which could be the result of
immunosuppression to protect developing embryos. Recent molecular
studies using both candidate-gene and next-generation sequencing
approaches have suggested that at least some of the genes and gene
families underlying these phenomena play similar roles in the uterus and
placenta of viviparous mammals and squamates. Therefore, studies of the
evolution of viviparity in squamates should inform hypotheses of the
evolution of viviparity in all amniotes, including mammals.

Here's another: https://pubmed.ncbi.nlm.nih.gov/21573966/

There are more, but you can google.
> Capice?

This would be a better discussion if you didn't resort to condescension
so early into it.

On Friday, August 26, 2022 at 6:47:42 PM UTC-4, thesigh...@gmail.com wrote:
> Wasn’t there something about reptile eggs needing to breathe or something? I supose amphibian eggs can be underwater; are reptile eggs the same way?

No. In fact, turtles always lay their eggs on land, and some will go to great distances to do it:

Turtles, including sea turtles, lay their eggs on land, although some lay eggs close near water that rises and falls in level, submerging the eggs. While most species build nests and lay eggs where they forage, some travel miles. The common snapping turtle walks 5 km (3 mi) on land, while sea turtles travel even further; the leatherback swims some 12,000 km (7,500 mi) to its nesting beaches.[13][85]
https://en.wikipedia.org/wiki/Turtle#Eggs_and_hatchlings

This makes sea turtles highly vulnerable to humans with a taste for turtle eggs,
and the fact that beaches are such a popular destination makes the situation worse.

Here in South Carolina, signs are posted telling people not to
disturb turtles in the process of laying eggs, nor to dig on the beaches
at designated areas that are known to be favored for egg laying.

Back to the differences: the very thing that separates amniotes
from amphibians is the extraembryonic members [1], of which the chorion and amnion
keep the embryo from drying out. Hence common snapping turtles seem
to specifically want to get away from water, as the quote from Wikipedia above suggests.

[1] In this context, "membrane" is a mis-translation of the Latin "membranum"; granted,
the amnion is a membrane in the usual sense of the word.

I've been wondering for a long time about something that the Wiki excerpt
addresses with:

"some lay eggs close near water that rises and falls in level, submerging the eggs."

So it looks like some turtle eggs are dependent on water to some extent.

Here is what I've been wondering about. With few exceptions, turtles
(snapping turtles are a well known exception) have soft-shelled eggs, and
perhaps it is important for the ground in which they are laid to remain moist.

Or perhaps not for some species; perhaps some also need a drying-out period, like low tide on the beach.

Does anyone reading this know more about this?

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

Sorry everyone, Mr. Slow here again (I’m the one for whom the saying, “He who laughs last did not get the joke” was invented)

Anyway, would it be correct to summarize the above as saying that reptiles evolved from true “egg laying” to simply keeping eggs within the body until they “hatched” several times within their history? I guess that would make the difference between external egg laying and viviparous birth more of continuum than a hard line.

Would it be possible for something like Ichthyosaur eggs to evolve “backwards” from a hard reptilian shell egg back to goopy, unshelled, caviar-like blobs of jelly?

On Friday, August 26, 2022 at 9:09:36 PM UTC-4, John Harshman wrote:
> On 8/26/22 5:12 PM, Peter Nyikos wrote:
> > On Friday, August 26, 2022 at 7:16:18 PM UTC-4, erik simpson wrote:
> >> On Friday, August 26, 2022 at 3:42:40 PM UTC-7, peter2...@gmail.com wrote:
> >>> On Friday, August 26, 2022 at 6:32:49 PM UTC-4, Peter Nyikos wrote:
> >>>
> >>>> You aren't contributing anything to the on-topic discussion in this second post of yours, Erik.
> >
> >>> Minor technical exception: you completed the three-line description of Ovoviviparity in
> >>> https://en.wikipedia.org/wiki/Viviparity
> >>> of which I had posted the first sentence.
> >
> >> You're contributing what I see as a substantial digression into Mammalia. As for vipers, "squamate reproductive
> >> strategies are almost bimodally divided between oviparity (egg laying), including cases of egg retention up to limb-bud stage,
> >> and viviparity involving functional placentation". I don't understand what's frustrating.
> >
> > The fact that the claim could be wrong [see reasoning below], and thus being used fallaciously to support
> > viviparity in ichthyosaurs, which is at the exact resonant center of this thread.

> If you want to find about whether the claims in that paper are wrong,
> you should consult the references cited to support the claims. In this
> case that would seem to be references 2 and 22.

[2] doesn't even use the term "ovoviviparous". It could, of course, be paraphrased
somewhere, but it's getting late and so I'm postponing this project for the weekend,
which means reporting on anything relevant on Monday or Tuesday.

As for [22], what I posted on that earlier was preserved in the post that neither Erik
nor you have shown any sign of having read, preferring the small correction which
followed it almost immediately.

[repost from uncorrected post]
> > [22] is linked to a mere abstract via Google Scholar, while "View Article" just takes us back
> > to the article itself! The same goes for [23].
[end of repost]

I'll try to Google them on ResearchGate, like I did the reference you gave me next, but the
same thing applies that applies above.

> > I guess the shortness of the post attracted you like a magnet, causing you
> > to miss out on the original post, including the following reasoning:
> >
> > ___________________________ first excerpt from the original post_________________
> >
> >> but I don't see any need to be frustrated. Again, from the paper: "Given these observations, it would be reasonable if viviparity in Chaohusaurus
> >> involved a degree of placentation. However, this inference cannot be tested directly with fossil evidence because the
> >> soft tissue is not preserved."
> >
> > This is the second subset of what I quoted, and is why I find vipers so frustrating.
> > For all I know, they might be mostly viviparous [which would make the inference "reasonable"]
> > or all ovoviviparous [which would make the inference almost untenable, given the variety of vipers].

> Apparently, "ovoviviparous" is ambiguous and not a useful term.
> Apparently, retention of the eggs until hatching (or birth, if you
> prefer) requires maternal nourishment of the eggs, at least in squamates.

What is the reasoning/reference behind "Apparently"?

> > ======================== end of first excerpt =======================
> >
> > And here is why the "Given" is seriously affected:
> >
> > ######################## second excerpt from the original post #####################
> >
> >> From the paper "squamate reproductive strategies are almost bimodally divided between oviparity (egg laying), including
> >> cases of egg retention up to limb-bud stage, and viviparity involving functional placentation, with few
> >> intermediate forms." (Refences cited in the paper)
> >
> > This is the first subset that I mentioned above.
> >
> > ************************************************************ end of second excerpt
> > from
> > https://groups.google.com/g/sci.bio.paleontology/c/X2eRy1wQf8U/m/4I_chwJ8AQAJ
> > Re: Were Ichthyosaurs Ovoviviparous, or Viviparous?
> >
> > And, lest your memory fail you between the first repost and the second, compare:
> >
> > "make the inference almost untenable, given the variety of vipers".
> > and
> >> "almost bimodally, ... with few intermediate forms."

> The second quote would seem to entail that the first quote is wrong.
> Have you tried looking at the cited references? Have you searched for a
> review of squamate viviparity?

There has been too little time for that. The whole topic of this thread came
as a brainstorm as I was lying awake this morning around 6 am.
Until then the issue had never occurred to me.

>
> Here's one: https://rep.bioscientifica.com/view/journals/rep/147/1/R15.xml
>
> Abstract: Squamate reptiles (lizards and snakes) are an ideal model
> system for testing hypotheses regarding the evolution of viviparity
> (live birth) in amniote vertebrates. Viviparity has evolved over 100
> times in squamates, resulting in major changes in reproductive
> physiology. At a minimum, all viviparous squamates exhibit placentae
> formed by the appositions of maternal and embryonic tissues, which are
> homologous in origin with the tissues that form the placenta in therian
> mammals. These placentae facilitate adhesion of the conceptus to the
> uterus as well as exchange of oxygen, carbon dioxide, water, sodium, and
> calcium. However, most viviparous squamates continue to rely on yolk for
> nearly all of their organic nutrition. In contrast, some species, which
> rely on the placenta for at least a portion of organic nutrition,
> exhibit complex placental specializations associated with the transport
> of amino acids and fatty acids. Some viviparous squamates also exhibit
> reduced immunocompetence during pregnancy, which could be the result of
> immunosuppression to protect developing embryos. Recent molecular
> studies using both candidate-gene and next-generation sequencing
> approaches have suggested that at least some of the genes and gene
> families underlying these phenomena play similar roles in the uterus and
> placenta of viviparous mammals and squamates. Therefore, studies of the
> evolution of viviparity in squamates should inform hypotheses of the
> evolution of viviparity in all amniotes, including mammals.

Thanks, that may be the first paper I look up.

> Here's another: https://pubmed.ncbi.nlm.nih.gov/21573966/
>
> There are more, but you can google.
> > Capice?
>
> This would be a better discussion if you didn't resort to condescension
> so early into it.

This from someone who has treated me with gratuitous condescension
in talk.origins for almost a dozen years, and in sci.bio.paleontology for about
half as long, with two completely contrasting breaks: Thrinaxodon (later nym: Oxyaena) almost
destroying s.b.p with relentless crazy spam, and what I call the Oasis
of Civilization Period, which lasted from mid-2015 to early 2018.

But, on a less aggressive note, the discussion seemed to have
died out until you and Sight Reader came along.

Peter Nyikos

On 8/26/22 6:28 PM, Sight Reader wrote:
> Sorry everyone, Mr. Slow here again (I’m the one for whom the saying, “He who laughs last did not get the joke” was invented)
>
> Anyway, would it be correct to summarize the above as saying that reptiles evolved from true “egg laying” to simply keeping eggs within the body until they “hatched” several times within their history?

Apparently not, based on the literature I've seen. There are 108
evolutions of viviparity in squamates, but every one of them involves
more than just keeping the eggs inside.

> I guess that would make the difference between external egg laying and viviparous birth more of continuum than a hard line.
>
> Would it be possible for something like Ichthyosaur eggs to evolve “backwards” from a hard reptilian shell egg back to goopy, unshelled, caviar-like blobs of jelly?

Simple enough. Eggs only get their shells as they pass through the
oviduct. That whole thing could be suppressed with a few mutations.

On 8/26/22 7:04 PM, Peter Nyikos wrote:
> On Friday, August 26, 2022 at 9:09:36 PM UTC-4, John Harshman wrote:
>> On 8/26/22 5:12 PM, Peter Nyikos wrote:
>>> On Friday, August 26, 2022 at 7:16:18 PM UTC-4, erik simpson wrote:
>>>> On Friday, August 26, 2022 at 3:42:40 PM UTC-7, peter2...@gmail.com wrote:
>>>>> On Friday, August 26, 2022 at 6:32:49 PM UTC-4, Peter Nyikos wrote:
>>>>>
>>>>>> You aren't contributing anything to the on-topic discussion in this second post of yours, Erik.
>>>
>>>>> Minor technical exception: you completed the three-line description of Ovoviviparity in
>>>>> https://en.wikipedia.org/wiki/Viviparity
>>>>> of which I had posted the first sentence.
>>>
>>>> You're contributing what I see as a substantial digression into Mammalia. As for vipers, "squamate reproductive
>>>> strategies are almost bimodally divided between oviparity (egg laying), including cases of egg retention up to limb-bud stage,
>>>> and viviparity involving functional placentation". I don't understand what's frustrating.
>>>
>>> The fact that the claim could be wrong [see reasoning below], and thus being used fallaciously to support
>>> viviparity in ichthyosaurs, which is at the exact resonant center of this thread.
>
>> If you want to find about whether the claims in that paper are wrong,
>> you should consult the references cited to support the claims. In this
>> case that would seem to be references 2 and 22.
>
> [2] doesn't even use the term "ovoviviparous". It could, of course, be paraphrased
> somewhere, but it's getting late and so I'm postponing this project for the weekend,
> which means reporting on anything relevant on Monday or Tuesday.

Perhaps 2 doesn't use it because it's not a useful term.

> As for [22], what I posted on that earlier was preserved in the post that neither Erik
> nor you have shown any sign of having read, preferring the small correction which
> followed it almost immediately.
>
> [repost from uncorrected post]
>>> [22] is linked to a mere abstract via Google Scholar, while "View Article" just takes us back
>>> to the article itself! The same goes for [23].
> [end of repost]

You may have to find the actual paper. Donk't your university resources
work for that?

> I'll try to Google them on ResearchGate, like I did the reference you gave me next, but the
> same thing applies that applies above.
>
>>> I guess the shortness of the post attracted you like a magnet, causing you
>>> to miss out on the original post, including the following reasoning:
>>>
>>> ___________________________ first excerpt from the original post_________________
>>>
>>>> but I don't see any need to be frustrated. Again, from the paper: "Given these observations, it would be reasonable if viviparity in Chaohusaurus
>>>> involved a degree of placentation. However, this inference cannot be tested directly with fossil evidence because the
>>>> soft tissue is not preserved."
>>>
>>> This is the second subset of what I quoted, and is why I find vipers so frustrating.
>>> For all I know, they might be mostly viviparous [which would make the inference "reasonable"]
>>> or all ovoviviparous [which would make the inference almost untenable, given the variety of vipers].
>
>> Apparently, "ovoviviparous" is ambiguous and not a useful term.
>> Apparently, retention of the eggs until hatching (or birth, if you
>> prefer) requires maternal nourishment of the eggs, at least in squamates.
>
>
> What is the reasoning/reference behind "Apparently"?
>
>
>
>>> ======================== end of first excerpt =======================
>>>
>>> And here is why the "Given" is seriously affected:
>>>
>>> ######################## second excerpt from the original post #####################
>>>
>>>> From the paper "squamate reproductive strategies are almost bimodally divided between oviparity (egg laying), including
>>>> cases of egg retention up to limb-bud stage, and viviparity involving functional placentation, with few
>>>> intermediate forms." (Refences cited in the paper)
>>>
>>> This is the first subset that I mentioned above.
>>>
>>> ************************************************************ end of second excerpt
>>> from
>>> https://groups.google.com/g/sci.bio.paleontology/c/X2eRy1wQf8U/m/4I_chwJ8AQAJ
>>> Re: Were Ichthyosaurs Ovoviviparous, or Viviparous?
>>>
>>> And, lest your memory fail you between the first repost and the second, compare:
>>>
>>> "make the inference almost untenable, given the variety of vipers".
>>> and
>>>> "almost bimodally, ... with few intermediate forms."
>
>> The second quote would seem to entail that the first quote is wrong.
>> Have you tried looking at the cited references? Have you searched for a
>> review of squamate viviparity?
>
> There has been too little time for that. The whole topic of this thread came
> as a brainstorm as I was lying awake this morning around 6 am.
> Until then the issue had never occurred to me.
>
>>
>> Here's one: https://rep.bioscientifica.com/view/journals/rep/147/1/R15.xml
>>
>> Abstract: Squamate reptiles (lizards and snakes) are an ideal model
>> system for testing hypotheses regarding the evolution of viviparity
>> (live birth) in amniote vertebrates. Viviparity has evolved over 100
>> times in squamates, resulting in major changes in reproductive
>> physiology. At a minimum, all viviparous squamates exhibit placentae
>> formed by the appositions of maternal and embryonic tissues, which are
>> homologous in origin with the tissues that form the placenta in therian
>> mammals. These placentae facilitate adhesion of the conceptus to the
>> uterus as well as exchange of oxygen, carbon dioxide, water, sodium, and
>> calcium. However, most viviparous squamates continue to rely on yolk for
>> nearly all of their organic nutrition. In contrast, some species, which
>> rely on the placenta for at least a portion of organic nutrition,
>> exhibit complex placental specializations associated with the transport
>> of amino acids and fatty acids. Some viviparous squamates also exhibit
>> reduced immunocompetence during pregnancy, which could be the result of
>> immunosuppression to protect developing embryos. Recent molecular
>> studies using both candidate-gene and next-generation sequencing
>> approaches have suggested that at least some of the genes and gene
>> families underlying these phenomena play similar roles in the uterus and
>> placenta of viviparous mammals and squamates. Therefore, studies of the
>> evolution of viviparity in squamates should inform hypotheses of the
>> evolution of viviparity in all amniotes, including mammals.
>
> Thanks, that may be the first paper I look up.
>
>> Here's another: https://pubmed.ncbi.nlm.nih.gov/21573966/
>>
>> There are more, but you can google.
>>> Capice?
>>
>> This would be a better discussion if you didn't resort to condescension
>> so early into it.
>
> This from someone who has treated me with gratuitous condescension
> in talk.origins for almost a dozen years, and in sci.bio.paleontology for about
> half as long, with two completely contrasting breaks: Thrinaxodon (later nym: Oxyaena) almost
> destroying s.b.p with relentless crazy spam, and what I call the Oasis
> of Civilization Period, which lasted from mid-2015 to early 2018.

You have to start letting go of ancient grievances if you actually want
to discuss the science.

> But, on a less aggressive note, the discussion seemed to have
> died out until you and Sight Reader came along.
>
>
> Peter Nyikos

On Friday, August 26, 2022 at 8:54:00 PM UTC-7, John Harshman wrote:
> On 8/26/22 7:04 PM, Peter Nyikos wrote:
> > On Friday, August 26, 2022 at 9:09:36 PM UTC-4, John Harshman wrote:
> >> On 8/26/22 5:12 PM, Peter Nyikos wrote:
> >>> On Friday, August 26, 2022 at 7:16:18 PM UTC-4, erik simpson wrote:
> >>>> On Friday, August 26, 2022 at 3:42:40 PM UTC-7, peter2...@gmail.com wrote:
> >>>>> On Friday, August 26, 2022 at 6:32:49 PM UTC-4, Peter Nyikos wrote:
> >>>>>
> >>>>>> You aren't contributing anything to the on-topic discussion in this second post of yours, Erik.
> >>>
> >>>>> Minor technical exception: you completed the three-line description of Ovoviviparity in
> >>>>> https://en.wikipedia.org/wiki/Viviparity
> >>>>> of which I had posted the first sentence.
> >>>
> >>>> You're contributing what I see as a substantial digression into Mammalia. As for vipers, "squamate reproductive
> >>>> strategies are almost bimodally divided between oviparity (egg laying), including cases of egg retention up to limb-bud stage,
> >>>> and viviparity involving functional placentation". I don't understand what's frustrating.
> >>>
> >>> The fact that the claim could be wrong [see reasoning below], and thus being used fallaciously to support
> >>> viviparity in ichthyosaurs, which is at the exact resonant center of this thread.
> >
> >> If you want to find about whether the claims in that paper are wrong,
> >> you should consult the references cited to support the claims. In this
> >> case that would seem to be references 2 and 22.
> >
> > [2] doesn't even use the term "ovoviviparous". It could, of course, be paraphrased
> > somewhere, but it's getting late and so I'm postponing this project for the weekend,
> > which means reporting on anything relevant on Monday or Tuesday.
> Perhaps 2 doesn't use it because it's not a useful term.
> > As for [22], what I posted on that earlier was preserved in the post that neither Erik
> > nor you have shown any sign of having read, preferring the small correction which
> > followed it almost immediately.
> >
> > [repost from uncorrected post]
> >>> [22] is linked to a mere abstract via Google Scholar, while "View Article" just takes us back
> >>> to the article itself! The same goes for [23].
> > [end of repost]
> You may have to find the actual paper. Donk't your university resources
> work for that?
> > I'll try to Google them on ResearchGate, like I did the reference you gave me next, but the
> > same thing applies that applies above.
> >
> >>> I guess the shortness of the post attracted you like a magnet, causing you
> >>> to miss out on the original post, including the following reasoning:
> >>>
> >>> ___________________________ first excerpt from the original post_________________
> >>>
> >>>> but I don't see any need to be frustrated. Again, from the paper: "Given these observations, it would be reasonable if viviparity in Chaohusaurus
> >>>> involved a degree of placentation. However, this inference cannot be tested directly with fossil evidence because the
> >>>> soft tissue is not preserved."
> >>>
> >>> This is the second subset of what I quoted, and is why I find vipers so frustrating.
> >>> For all I know, they might be mostly viviparous [which would make the inference "reasonable"]
> >>> or all ovoviviparous [which would make the inference almost untenable, given the variety of vipers].
> >
> >> Apparently, "ovoviviparous" is ambiguous and not a useful term.
> >> Apparently, retention of the eggs until hatching (or birth, if you
> >> prefer) requires maternal nourishment of the eggs, at least in squamates.
> >
> >
> > What is the reasoning/reference behind "Apparently"?
> >
> >
> >
> >>> ======================== end of first excerpt =======================
> >>>
> >>> And here is why the "Given" is seriously affected:
> >>>
> >>> ######################## second excerpt from the original post #####################
> >>>
> >>>> From the paper "squamate reproductive strategies are almost bimodally divided between oviparity (egg laying), including
> >>>> cases of egg retention up to limb-bud stage, and viviparity involving functional placentation, with few
> >>>> intermediate forms." (Refences cited in the paper)
> >>>
> >>> This is the first subset that I mentioned above.
> >>>
> >>> ************************************************************ end of second excerpt
> >>> from
> >>> https://groups.google.com/g/sci.bio.paleontology/c/X2eRy1wQf8U/m/4I_chwJ8AQAJ
> >>> Re: Were Ichthyosaurs Ovoviviparous, or Viviparous?
> >>>
> >>> And, lest your memory fail you between the first repost and the second, compare:
> >>>
> >>> "make the inference almost untenable, given the variety of vipers".
> >>> and
> >>>> "almost bimodally, ... with few intermediate forms."
> >
> >> The second quote would seem to entail that the first quote is wrong.
> >> Have you tried looking at the cited references? Have you searched for a
> >> review of squamate viviparity?
> >
> > There has been too little time for that. The whole topic of this thread came
> > as a brainstorm as I was lying awake this morning around 6 am.
> > Until then the issue had never occurred to me.
> >
> >>
> >> Here's one: https://rep.bioscientifica.com/view/journals/rep/147/1/R15.xml
> >>
> >> Abstract: Squamate reptiles (lizards and snakes) are an ideal model
> >> system for testing hypotheses regarding the evolution of viviparity
> >> (live birth) in amniote vertebrates. Viviparity has evolved over 100
> >> times in squamates, resulting in major changes in reproductive
> >> physiology. At a minimum, all viviparous squamates exhibit placentae
> >> formed by the appositions of maternal and embryonic tissues, which are
> >> homologous in origin with the tissues that form the placenta in therian
> >> mammals. These placentae facilitate adhesion of the conceptus to the
> >> uterus as well as exchange of oxygen, carbon dioxide, water, sodium, and
> >> calcium. However, most viviparous squamates continue to rely on yolk for
> >> nearly all of their organic nutrition. In contrast, some species, which
> >> rely on the placenta for at least a portion of organic nutrition,
> >> exhibit complex placental specializations associated with the transport
> >> of amino acids and fatty acids. Some viviparous squamates also exhibit
> >> reduced immunocompetence during pregnancy, which could be the result of
> >> immunosuppression to protect developing embryos. Recent molecular
> >> studies using both candidate-gene and next-generation sequencing
> >> approaches have suggested that at least some of the genes and gene
> >> families underlying these phenomena play similar roles in the uterus and
> >> placenta of viviparous mammals and squamates. Therefore, studies of the
> >> evolution of viviparity in squamates should inform hypotheses of the
> >> evolution of viviparity in all amniotes, including mammals.
> >
> > Thanks, that may be the first paper I look up.
> >
> >> Here's another: https://pubmed.ncbi.nlm.nih.gov/21573966/
> >>
> >> There are more, but you can google.
> >>> Capice?
> >>
> >> This would be a better discussion if you didn't resort to condescension
> >> so early into it.
> >
> > This from someone who has treated me with gratuitous condescension
> > in talk.origins for almost a dozen years, and in sci.bio.paleontology for about
> > half as long, with two completely contrasting breaks: Thrinaxodon (later nym: Oxyaena) almost
> > destroying s.b.p with relentless crazy spam, and what I call the Oasis
> > of Civilization Period, which lasted from mid-2015 to early 2018.
> You have to start letting go of ancient grievances if you actually want
> to discuss the science.
> > But, on a less aggressive note, the discussion seemed to have
> > died out until you and Sight Reader came along.
> >
> >
> > Peter Nyikos

On Saturday, August 27, 2022 at 10:59:32 AM UTC-7, erik simpson wrote:
> On Friday, August 26, 2022 at 8:54:00 PM UTC-7, John Harshman wrote:
> > On 8/26/22 7:04 PM, Peter Nyikos wrote:
> > > On Friday, August 26, 2022 at 9:09:36 PM UTC-4, John Harshman wrote:
> > >> On 8/26/22 5:12 PM, Peter Nyikos wrote:
> > >>> On Friday, August 26, 2022 at 7:16:18 PM UTC-4, erik simpson wrote:
> > >>>> On Friday, August 26, 2022 at 3:42:40 PM UTC-7, peter2...@gmail.com wrote:
> > >>>>> On Friday, August 26, 2022 at 6:32:49 PM UTC-4, Peter Nyikos wrote:
> > >>>>>
> > >>>>>> You aren't contributing anything to the on-topic discussion in this second post of yours, Erik.
> > >>>
> > >>>>> Minor technical exception: you completed the three-line description of Ovoviviparity in
> > >>>>> https://en.wikipedia.org/wiki/Viviparity
> > >>>>> of which I had posted the first sentence.
> > >>>
> > >>>> You're contributing what I see as a substantial digression into Mammalia. As for vipers, "squamate reproductive
> > >>>> strategies are almost bimodally divided between oviparity (egg laying), including cases of egg retention up to limb-bud stage,
> > >>>> and viviparity involving functional placentation". I don't understand what's frustrating.
> > >>>
> > >>> The fact that the claim could be wrong [see reasoning below], and thus being used fallaciously to support
> > >>> viviparity in ichthyosaurs, which is at the exact resonant center of this thread.
> > >
> > >> If you want to find about whether the claims in that paper are wrong,
> > >> you should consult the references cited to support the claims. In this
> > >> case that would seem to be references 2 and 22.
> > >
> > > [2] doesn't even use the term "ovoviviparous". It could, of course, be paraphrased
> > > somewhere, but it's getting late and so I'm postponing this project for the weekend,
> > > which means reporting on anything relevant on Monday or Tuesday.
> > Perhaps 2 doesn't use it because it's not a useful term.
> > > As for [22], what I posted on that earlier was preserved in the post that neither Erik
> > > nor you have shown any sign of having read, preferring the small correction which
> > > followed it almost immediately.
> > >
> > > [repost from uncorrected post]
> > >>> [22] is linked to a mere abstract via Google Scholar, while "View Article" just takes us back
> > >>> to the article itself! The same goes for [23].
> > > [end of repost]
> > You may have to find the actual paper. Donk't your university resources
> > work for that?
> > > I'll try to Google them on ResearchGate, like I did the reference you gave me next, but the
> > > same thing applies that applies above.
> > >
> > >>> I guess the shortness of the post attracted you like a magnet, causing you
> > >>> to miss out on the original post, including the following reasoning:
> > >>>
> > >>> ___________________________ first excerpt from the original post_________________
> > >>>
> > >>>> but I don't see any need to be frustrated. Again, from the paper: "Given these observations, it would be reasonable if viviparity in Chaohusaurus
> > >>>> involved a degree of placentation. However, this inference cannot be tested directly with fossil evidence because the
> > >>>> soft tissue is not preserved."
> > >>>
> > >>> This is the second subset of what I quoted, and is why I find vipers so frustrating.
> > >>> For all I know, they might be mostly viviparous [which would make the inference "reasonable"]
> > >>> or all ovoviviparous [which would make the inference almost untenable, given the variety of vipers].
> > >
> > >> Apparently, "ovoviviparous" is ambiguous and not a useful term.
> > >> Apparently, retention of the eggs until hatching (or birth, if you
> > >> prefer) requires maternal nourishment of the eggs, at least in squamates.
> > >
> > >
> > > What is the reasoning/reference behind "Apparently"?
> > >
> > >
> > >
> > >>> ======================== end of first excerpt =======================
> > >>>
> > >>> And here is why the "Given" is seriously affected:
> > >>>
> > >>> ######################## second excerpt from the original post #####################
> > >>>
> > >>>> From the paper "squamate reproductive strategies are almost bimodally divided between oviparity (egg laying), including
> > >>>> cases of egg retention up to limb-bud stage, and viviparity involving functional placentation, with few
> > >>>> intermediate forms." (Refences cited in the paper)
> > >>>
> > >>> This is the first subset that I mentioned above.
> > >>>
> > >>> ************************************************************ end of second excerpt
> > >>> from
> > >>> https://groups.google.com/g/sci.bio.paleontology/c/X2eRy1wQf8U/m/4I_chwJ8AQAJ
> > >>> Re: Were Ichthyosaurs Ovoviviparous, or Viviparous?
> > >>>
> > >>> And, lest your memory fail you between the first repost and the second, compare:
> > >>>
> > >>> "make the inference almost untenable, given the variety of vipers".
> > >>> and
> > >>>> "almost bimodally, ... with few intermediate forms."
> > >
> > >> The second quote would seem to entail that the first quote is wrong.
> > >> Have you tried looking at the cited references? Have you searched for a
> > >> review of squamate viviparity?
> > >
> > > There has been too little time for that. The whole topic of this thread came
> > > as a brainstorm as I was lying awake this morning around 6 am.
> > > Until then the issue had never occurred to me.
> > >
> > >>
> > >> Here's one: https://rep.bioscientifica.com/view/journals/rep/147/1/R15.xml
> > >>
> > >> Abstract: Squamate reptiles (lizards and snakes) are an ideal model
> > >> system for testing hypotheses regarding the evolution of viviparity
> > >> (live birth) in amniote vertebrates. Viviparity has evolved over 100
> > >> times in squamates, resulting in major changes in reproductive
> > >> physiology. At a minimum, all viviparous squamates exhibit placentae
> > >> formed by the appositions of maternal and embryonic tissues, which are
> > >> homologous in origin with the tissues that form the placenta in therian
> > >> mammals. These placentae facilitate adhesion of the conceptus to the
> > >> uterus as well as exchange of oxygen, carbon dioxide, water, sodium, and
> > >> calcium. However, most viviparous squamates continue to rely on yolk for
> > >> nearly all of their organic nutrition. In contrast, some species, which
> > >> rely on the placenta for at least a portion of organic nutrition,
> > >> exhibit complex placental specializations associated with the transport
> > >> of amino acids and fatty acids. Some viviparous squamates also exhibit
> > >> reduced immunocompetence during pregnancy, which could be the result of
> > >> immunosuppression to protect developing embryos. Recent molecular
> > >> studies using both candidate-gene and next-generation sequencing
> > >> approaches have suggested that at least some of the genes and gene
> > >> families underlying these phenomena play similar roles in the uterus and
> > >> placenta of viviparous mammals and squamates. Therefore, studies of the
> > >> evolution of viviparity in squamates should inform hypotheses of the
> > >> evolution of viviparity in all amniotes, including mammals.
> > >
> > > Thanks, that may be the first paper I look up.
> > >
> > >> Here's another: https://pubmed.ncbi.nlm.nih.gov/21573966/
> > >>
> > >> There are more, but you can google.
> > >>> Capice?
> > >>
> > >> This would be a better discussion if you didn't resort to condescension
> > >> so early into it.
> > >
> > > This from someone who has treated me with gratuitous condescension
> > > in talk.origins for almost a dozen years, and in sci.bio.paleontology for about
> > > half as long, with two completely contrasting breaks: Thrinaxodon (later nym: Oxyaena) almost
> > > destroying s.b.p with relentless crazy spam, and what I call the Oasis
> > > of Civilization Period, which lasted from mid-2015 to early 2018.
> > You have to start letting go of ancient grievances if you actually want
> > to discuss the science.
> > > But, on a less aggressive note, the discussion seemed to have
> > > died out until you and Sight Reader came along.
> > >
> > >
> > > Peter Nyikos
> He can't help it. I'm not going to continue with such an edgy exchange.

On Friday, August 26, 2022 at 8:04:19 PM UTC-6, peter2...@gmail.com wrote:
> But, on a less aggressive note, the discussion seemed to have
> died out until you and Sight Reader came along.

Oh no! Sorry… I didn’t mean to start a flame war! (tries to hide his poisonous keyboard behind his back…)

On Saturday, August 27, 2022 at 2:02:33 PM UTC-7, thesigh...@gmail.com wrote:
> On Friday, August 26, 2022 at 8:04:19 PM UTC-6, peter2...@gmail.com wrote:
> > But, on a less aggressive note, the discussion seemed to have
> > died out until you and Sight Reader came along.
> Oh no! Sorry… I didn’t mean to start a flame war! (tries to hide his poisonous keyboard behind his back…)

No cause to be sorry, or even concerned. As you've gathered, Peter is a man of very strong opinions, very
forcefully expressed on a very broad range of subjects. He's been here for a long time, and some of this ideas
are very controversial. As a result, discussions often become contentious. Some posters here (and on talk.origins)
get along with him better than others. Stick around, and you'll see why. Open mind, and all that. Unfortunately, it's
been years since any professional paleontologists or even people on that track have been regular participants.
Everybody here is an amateur of whatever grade. John is the closest, as an ornithogist and systematist, Some of the
rest may have advanced degrees in something, but for the most part interest is all we've got in common.

On 8/27/22 4:05 PM, erik simpson wrote:
> On Saturday, August 27, 2022 at 2:02:33 PM UTC-7, thesigh...@gmail.com wrote:
>> On Friday, August 26, 2022 at 8:04:19 PM UTC-6, peter2...@gmail.com wrote:
>>> But, on a less aggressive note, the discussion seemed to have
>>> died out until you and Sight Reader came along.
>> Oh no! Sorry… I didn’t mean to start a flame war! (tries to hide his poisonous keyboard behind his back…)
>
> No cause to be sorry, or even concerned. As you've gathered, Peter is a man of very strong opinions, very
> forcefully expressed on a very broad range of subjects. He's been here for a long time, and some of this ideas
> are very controversial. As a result, discussions often become contentious. Some posters here (and on talk.origins)
> get along with him better than others. Stick around, and you'll see why. Open mind, and all that. Unfortunately, it's
> been years since any professional paleontologists or even people on that track have been regular participants.
> Everybody here is an amateur of whatever grade. John is the closest, as an ornithogist and systematist, Some of the
> rest may have advanced degrees in something, but for the most part interest is all we've got in common.

You forget Pandora, who admittedly isn't as regular as some.

On Sat, 27 Aug 2022 16:05:35 -0700 (PDT), erik simpson
<eastside.erik@gmail.com> wrote:

>On Saturday, August 27, 2022 at 2:02:33 PM UTC-7, thesigh...@gmail.com wrote:
>> On Friday, August 26, 2022 at 8:04:19 PM UTC-6, peter2...@gmail.com wrote:
>> > But, on a less aggressive note, the discussion seemed to have
>> > died out until you and Sight Reader came along.
>> Oh no! Sorry… I didn’t mean to start a flame war! (tries to hide his poisonous keyboard behind his back…)
>
>No cause to be sorry, or even concerned. As you've gathered, Peter is a man of very strong opinions, very
>forcefully expressed on a very broad range of subjects. He's been here for a long time, and some of this ideas
>are very controversial. As a result, discussions often become contentious. Some posters here (and on talk.origins)
>get along with him better than others. Stick around, and you'll see why. Open mind, and all that. Unfortunately, it's
>been years since any professional paleontologists or even people on that track have been regular participants.
>Everybody here is an amateur of whatever grade. John is the closest, as an ornithogist and systematist, Some of the
>rest may have advanced degrees in something, but for the most part interest is all we've got in common.

You are way too charitable. None of of the characteristics you
describe above inform my responses to the peter's posts.

On Saturday, August 27, 2022 at 10:04:26 PM UTC-7, John Harshman wrote:
> On 8/27/22 4:05 PM, erik simpson wrote:
> > On Saturday, August 27, 2022 at 2:02:33 PM UTC-7, thesigh...@gmail.com wrote:
> >> On Friday, August 26, 2022 at 8:04:19 PM UTC-6, peter2...@gmail.com wrote:
> >>> But, on a less aggressive note, the discussion seemed to have
> >>> died out until you and Sight Reader came along.
> >> Oh no! Sorry… I didn’t mean to start a flame war! (tries to hide his poisonous keyboard behind his back…)
> >
> > No cause to be sorry, or even concerned. As you've gathered, Peter is a man of very strong opinions, very
> > forcefully expressed on a very broad range of subjects. He's been here for a long time, and some of this ideas
> > are very controversial. As a result, discussions often become contentious. Some posters here (and on talk.origins)
> > get along with him better than others. Stick around, and you'll see why.. Open mind, and all that. Unfortunately, it's
> > been years since any professional paleontologists or even people on that track have been regular participants.
> > Everybody here is an amateur of whatever grade. John is the closest, as an ornithogist and systematist, Some of the
> > rest may have advanced degrees in something, but for the most part interest is all we've got in common.
> You forget Pandora, who admittedly isn't as regular as some.

Indeed I did. I don't know who Pandora is, or what his/her qualifications are, but I'd be interested to know.
BTW, I described you as a "systematist". Is that correct or would "phylogeneticist" be more accurate? Both?
Christine Janis has also appeared, very irregularly and rarely, but certainly a "pro".

On Sunday, August 28, 2022 at 1:22:24 AM UTC-7, 69jp...@gmail.com wrote:
> On Sat, 27 Aug 2022 16:05:35 -0700 (PDT), erik simpson
> <eastsi...@gmail.com> wrote:
>
> >On Saturday, August 27, 2022 at 2:02:33 PM UTC-7, thesigh...@gmail.com wrote:
> >> On Friday, August 26, 2022 at 8:04:19 PM UTC-6, peter2...@gmail.com wrote:
> >> > But, on a less aggressive note, the discussion seemed to have
> >> > died out until you and Sight Reader came along.
> >> Oh no! Sorry… I didn’t mean to start a flame war! (tries to hide his poisonous keyboard behind his back…)
> >
> >No cause to be sorry, or even concerned. As you've gathered, Peter is a man of very strong opinions, very
> >forcefully expressed on a very broad range of subjects. He's been here for a long time, and some of this ideas
> >are very controversial. As a result, discussions often become contentious. Some posters here (and on talk.origins)
> >get along with him better than others. Stick around, and you'll see why. Open mind, and all that. Unfortunately, it's
> >been years since any professional paleontologists or even people on that track have been regular participants.
> >Everybody here is an amateur of whatever grade. John is the closest, as an ornithogist and systematist, Some of the
> >rest may have advanced degrees in something, but for the most part interest is all we've got in common.
> You are way too charitable. None of of the characteristics you
> describe above inform my responses to the peter's posts.

There are other characteristics of Peter's than I mentioned, but thesightreader is new here, so my
description is as anodyne as I could make it. If he (thesightreader) lingers long enough, he'll become
fully aware of them anyway. I don't find communicating directly with Peter is instructive or amusing
enough to make it worth the effort.