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of the range......any pics out there of elapsoides from off the coastal plain???.....or other states than the carolinas, fla,georgia???.....

I'd love to see some animals from the "interior" as well. I've only seen a handful from TN, KY, AL, MS, and LA. Any takers? Scott G.?

-Cole

i ain't seen none.....does elapsoides intergrate with amauara and sysplia?????......pics???

At least not with syspila. I have seen animals from the delta region of LA and MS that appear much more syspila-like than elapsoides-like, suggesting that amaura are intergrading with the former rather than the later.

See:

Armstrong, Frymire, and Zimmerer. Analysis of Sympatrick Populations of Lampropeltis triangulum syspila and Lampropeltis triangulum elapsoides, in Western Kentucky and Adjacent Tennessee with Relation to the Taxonomic Status of the Scarlet Kingsnake. Journal of Herpetology, Vol.35, No.4. Society for the Study of Reptiles and Amphibians, 2001.

Pryon and Burbrink. Neogene Diversification and Taxonomic Stability in the Snake Tribe Lampropeltini (Serpentes: Colubridae). Molecular Phylogenetics and Evolution 52 (2009) 524-529.

Greene, Zimmerer, Palmer, and Bernard. Diet Specialization by the Scarlet Kingsnake, Lampropeltis elapsoides (Colubridae). Reptiles and Amphibians, Vol.17, No.1. International Reptile Conservation Foundation, 2010.

I think I have .pdf's of the first two, if you can't find them.

-Cole

It was this very issue (among a few others) that became the basis for Harper's re-elevating L. t. elapsoides back to full species status in 2006.

Harper, who went on to do the mtDNA and phylogenetic work that now supports the idea that L. elapsoides does NOT intergrade with the rest of the L. triangulum complex, noted at least four references in the classical (i.e. meristics-based) literature that contradict Williams' widely held conclusions on this issue. I've summarized them from his dissertation below.

Blanchard (1921) wrote that L. t. elapsoides did not appear to intergrade with L. t. amaura in Louisiana or with any other member of the L. triangulum group except for the coastal plains milk snake. Mount (1975) stated that he saw no evidence of interbreeding between L. t. elapsoides and any L. triangulum in Alabama where their ranges overlap. And just recently, in 2001, Armstrong et al. specifically looked for evidence of interbreeding between L. t. elapsoides and L. t. syspila in Kentucky based on color pattern and scale counts. They concluded that there is likely no interbreeding between these subspecies in Kentucky, corroborating the findings of Collins and Hirschfield (1964) who concluded that Kentucky L. t. elapsoides show no signs of interbreeding with other L. triangulum.
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WOW......WELL DONE!!!!......would this sorta mean that the coastal plain may not be an intergrade between elapsoides and triangulum.....& might be more a form of sysplia/???.....ha...there IT is!!!!!.....let's see some outta the locale elapsoides....

Bob, how on earth would you come to that conclusion given that first "coastal plains" are not currently recognized AND that the literture cited noted that Elap's DID intergrade with "coastal plains"?? I think this only muddies the water, it doesnt do anything to clear it.

From Harper and Pfennig, 2008 in Nature:

"Three hypotheses can explain the evolution of a less mimetic form in allopatry. First, erosion of the mimetic phenotype may reflect genetic mixing of L. t. elapsoides with other, less mimetic L. triangulum subspecies in allopatry. Yet population genetic surveys of all L. triangulum subspecies in the United States, with the use of both mitochondrial and nuclear genomes, revealed no evidence of recent hybridization between L. t. epapsoides and any other subspecies of L. triangulum. For example, none of the allopatrick L. t. elapsoides individuals contained a mtDNA sequence (at the ND4, CytB 16S locus) characteristic of, or closely related to, any other currently recognized subspecies of L. triangulum in the United States. Indeed, given that the subspecies L. t. elapsoides seems to be only distantly related to other subspecies of L. triangulum in the eastern United States, recent hybridization between the two groups seems unlikely."

It seems well supported to conclude, at this time, that the form we know as "temporalis" is not the product of intergradation between L. elapsoides and L. triangulum, probably "deserves" subspecies status (as much as many other forms of the species), and is probably a relict population of syspila.

Further work by Pyron and Burbrink (2009, Molecular Phylogenetics and Evolution) also places L. elapsoides as sister to the clade containing L. pyromelana and L. zonata, while the "rest" of L. triangulum nests as sister to the L. getula plus L. extenuatum clade.

-Cole

I don't have time for this but here are a few comments on snippets of this:

"Yet population genetic surveys of all L. triangulum subspecies in the United States, with the use of both mitochondrial and nuclear genomes, revealed no evidence of recent hybridization between L. t. epapsoides and any other subspecies of L. triangulum."

The use of "recent" here is what gets me, define that, how do you know the difference. I think the proper term would be infrequent.

"For example, none of the allopatrick L. t. elapsoides individuals contained a mtDNA sequence (at the ND4, CytB 16S locus) characteristic of, or closely related to, any other currently recognized subspecies of L. triangulum in the United States."

This presumes that males of other forms would breed with female elaspsoides. There are obvious mechanical reasons why it doesn't work this way, which would not preclude the reverse!

Indeed, given that the subspecies L. t. elapsoides seems to be only distantly related to other subspecies of L. triangulum in the eastern United States, recent hybridization between the two groups seems unlikely."

I think the conclusion comes close but doesn't quite hit the nail on the head. Elapsoides are certainly divergent from other forms of NA milks but the relationship is obvious and the evidence that they have influenced southern populations of temporalis I think is beyond refuting whether you want to call it integration or hybridization is just semantics.

I also think that it should be said that there is an academic bias towards species splitting. There has been a faction that has wanted to separate elaspoides for a long time. IMHO, simple because these animals don't fit nicely into our little classification system is no reason to discount everything we know about this complex.
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“Nothing is at last sacred but the integrity of your own mind.” Emmerson

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Tony,

Thanks for the good discussion. This is much more producting and fun than some others, huh?

I took "recent" to mean "since divergence". When was that? Well, not "recently". LOL The qualifiers are a mystery, I suppose, but I didn't take them to imply that historic gene flow had ocurred. Rather, that ther was certainly no evidence for current or recent gene flow, and that the much older interactions were still unknown.

Tony said,
This presumes that males of other forms would breed with female elaspsoides. There are obvious mechanical reasons why it doesn't work this way, which would not preclude the reverse!

How so? Mitochondria are passed from a female to her offspring, so seeing triangulum mtDNA markers in elapsoides-looking animals would require, technically, a male elapsoides to breed with a female triangulum. Also, after several generations of this example breeding, genetic mixing would allow gene flow of said markers far and wide.

Thoughts?

-Cole

How so?

Imagine a male Labrador retrieve and a female beagle. I'd elaborate if not for the interest in preventing the thread from being pulled.

Mitochondria are passed from a female to her offspring, so seeing triangulum mtDNA markers in elapsoides-looking animals would require, technically, a male elapsoides to breed with a female triangulum.

You have to remember that elapoides is the more niche specific animal. Relatively, triangulum is a generalist so we're looking for elapsoides influence on triangulum. This is becasue added diversity would benefit a generalist while also being detrimental to a specialist. I'm not sure if that's clear, but you don't see mtDNA for the reasons I've pointed out, not necessarily because the two don't cross.

Also, after several generations of this example breeding, genetic mixing would allow gene flow of said markers far and wide.

Not necessarily, remember that only when a survival advantage is conferred will the frequency of a given genotype increase. That's plain and simple BIO 101. The principle applies to nucleic as well as mtDNA but in regard to mtDNA there is the added likelyhood of it never having been transferred in the first place.
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“Nothing is at last sacred but the integrity of your own mind.” Emmerson

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Imagine a male Labrador retrieve and a female beagle.

Ha ha! What I meant was that it isn't an impossibility, since it’s just as likely for a male elapsoides to stumble up on a female triangulum in that example, in which case the offspring would have triangulum mtDNA.

This is becasue added diversity would benefit a generalist while also being detrimental to a specialist. I'm not sure if that's clear, but you don't see mtDNA for the reasons I've pointed out, not necessarily because the two don't cross.

Such a situation would favor the development of reproductive isolation (pre-zygotic, post-zyotic, or both) by elapsoides, so the scenario presented is unrealistic in the long-term. The introduction of triangulum genes into elapsoides (and vice-versa) through repeated back-crossing (reticulation) would serve to assimilate both populations into one, and allow a more generalistic form than “pure” elapsoides.

Not necessarily, remember that only when a survival advantage is conferred will the frequency of a given genotype increase. That's plain and simple BIO 101.

Well, sort of… Without getting into the depths of Neutral Theory, etc., let’s suffice to say that so long as a genotype presents no DIS-advantage, it will increase in frequency. Let’s not forget that Bio 101 left some stuff out that Bio 556 cleared up for us… LOL The mechanics of evolution is fascinating stuff. Evolution by Mark Ridley, PhD is an excellent undergraduate reference.

The principle applies to nucleic as well as mtDNA but in regard to mtDNA there is the added likelyhood of it never having been transferred in the first place.

Negatory, Ghost Rider. Mitochondrial DNA is, for the most part, neutral to selection. That’s what has made it such a target for the “gel jockies”, since accumulated mutations are generally the result of random mutation and drift, without the influence of selection on their frequency.

Let’s keep this going!

-Cole

Ha ha! What I meant was that it isn't an impossibility,

I never said it was impossible just more unlikely, or at least that was the intent. You know beer and face-to-face communication on this would be a lot more fun!

The introduction of triangulum genes into elapsoides (and vice-versa) through repeated back-crossing (reticulation) would serve to assimilate both populations into one, and allow a more generalistic form than “pure” elapsoides.

So you're saying that just because two form can interbreed even if only to a limited extent that a natural niche would go unexploited? I don't buy it. This is a huge assumption but then given that its me pointing this out doesn't carry much weight.

Without getting into the depths of Neutral Theory, etc., let’s suffice to say that so long as a genotype presents no DIS-advantage, it will increase in frequency.

You are wrong here. If there is a disadvantage the frequency decreases! This is one of the founding principles of evolution and speciation. It has been mathematically demonstrated time and again to be true no matter how slight the advantage or disadvantage is.

Negatory, Ghost Rider. Mitochondrial DNA is, for the most part, neutral to selection.

You're not looking at the relationship. MtDNA doesn't exist without nucleic DNA. If the combined nucleic DNA from a cross does not confer an advantage, its frequency does not increase nor does that of the associated mtDNA.

I think that perhaps you are saying that it's neutral to environmental pressures but it certainly is not neutral in regard to competition within the population. Also, mtDNA drives cellular metabolism. I would hardly call metabolic efficiency, selection neutral. It fits right in there with the selection of the fittest.
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“Nothing is at last sacred but the integrity of your own mind.” Emmerson

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Tony,

You're right about that, man! I'd love to chat this out over a brewskie! Any thoughts of a trip out West? Yellowstone's close by...

So you're saying that just because two form can interbreed even if only to a limited extent that a natural niche would go unexploited? I don't buy it. This is a huge assumption but then given that its me pointing this out doesn't carry much weight.

No, that's not what I'm saying. On the contrary, I'm saying that since genetic pollution would decrease the fitness of a population of specialists (like elapsoides), that they would quickly develop reproductive isolation from the potentially polluting population (i.e. triangulum).

You are wrong here. If there is a disadvantage the frequency decreases! This is one of the founding principles of evolution and speciation. It has been mathematically demonstrated time and again to be true no matter how slight the advantage or disadvantage is.

Not wrong, misunderstood. I agree, if there's a disadvantageous mutation, its frequency will decrease (or never increase to begin with). However, a selectively neutral mutation (i.e. tongue color) will necessarily increase in frequency until it reaches mathematical equilibrium with the alternatives. A "neutral" mutation will not, however, increase in frequency as quickly as an advantageous mutation, nor will it likely be as prevalent.

You're not looking at the relationship. MtDNA doesn't exist without nucleic DNA. If the combined nucleic DNA from a cross does not confer an advantage, its frequency does not increase nor does that of the associated mtDNA.

Granted, a mitochondrion cannot survive (any more...) without a cell in which to live. My wording may have been confusing. I meant neutral in the sense of a "silent mutation", in which the mutation affects codons that have neither positive nor negative results in the cell.

Also, mtDNA drives cellular metabolism. I would hardly call metabolic efficiency, selection neutral. It fits right in there with the selection of the fittest.

Nuclear DNA is the source for nearly all mitochondrial proteins. The "average" animal mitochondrion contains a number of DNA "rings". The genes on these rings code mainly for transfer and messanger RNA. There are plenty of selectively neutral (or nearly so) mutations that take place in mtDNA. Mitochondrial DNA is far less conserved than nDNA, has a much higher mutation rate, and in most organisms, only undergoes recombination with copies of itself. In spite of all of these nifty things about mtDNA, it has some shortfalls. As we both know, it only tells part of the story (though a larger part than some would think) and is best combined with nDNA to get a fuller picture.

-Cole

Would love to make it out west again sometime soon. Herp wise my AZ trip was a bust but then that's not why I went there. Looking to do several forays in the next couple of years. OK here we go:

I'm saying that since genetic pollution would decrease the fitness of a population of specialists (like elapsoides), that they would quickly develop reproductive isolation from the potentially polluting population (i.e. triangulum).

I don't think that's how it works, reproductive isolation is a consequence of adaptation, it is not a strategy towards isolation. As I see it isolation begins a mere function of behavior, which in turn allows opportunity for true genetic divergence.

However, a selectively neutral mutation (i.e. tongue color) will necessarily increase in frequency until it reaches mathematical equilibrium with the alternatives.

I still say you have this wrong, genetic frequency only increases when there is a conferred advantage.

Nuclear DNA is the source for nearly all mitochondrial proteins. The "average" animal mitochondrion contains a number of DNA "rings". The genes on these rings code mainly for transfer and messanger RNA. There are plenty of selectively neutral (or nearly so) mutations that take place in mtDNA. Mitochondrial DNA is far less conserved than nDNA, has a much higher mutation rate, and in most organisms, only undergoes recombination with copies of itself. In spite of all of these nifty things about mtDNA, it has some shortfalls. As we both know, it only tells part of the story (though a larger part than some would think) and is best combined with nDNA to get a fuller picture.

I'm certainly no expert on the ins and outs of DNA but I do know that at least in human history there have been periodic shifts in mtDNA that have gone on to become the dominant form. This would not be the case unless there was some advantage specific to the mtDNA. Otherwise it would remain a very rare variant. I think your assumptions here are based on your view that "neutral mutation (i.e. tongue color) will necessarily increase in frequency until it reaches mathematical equilibrium with the alternatives". As I've said I believe this to be dead wrong and until I see it proven otherwise we'll just have to agree to disagree on this one.

OK so let me sum up my position here and what I think the real issue is.

People are saying that because there is no mtDNA evidence of crossing that it didn't / doesn't happen. I'm saying that there are other reasons even though I recognize that elapsoides is quite divergent form other triangulum. So here are the reasons

#1 Crossings between a generalist and a specialist do not have the same effect in that the influence is detrimental to the specialist. As such nature is going to select against the crosses in specific niches eventually eradicating any genetic markers. For this reason looking for Ltt markers in Lte is a dead ended search. if you want to see evidence you need to look for the opposite Lte markets in Ltt as these would have the greatest chance to persist.

#2 Though this is not absolute, male Ltt breeding with Lte is much less likely than the opposite. This in conjunction with #1 means that the likelihood that there would be any mtDNA transfer into the generalist form again decreasing the likelihood that you'd find significant markers

#3 is the stable environment argument. When there is rapid environmental change niche barriers break down and animals that ordinarily wouldn't find opportunities to breed do. Such an event allowed Lte to influence immigrant syspila populations that founded what we now recognize as southern populations of temporalis.
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“Nothing is at last sacred but the integrity of your own mind.” Emmerson

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Tony,

I don't disagree with all of your point. I'm running short on time here (getting married on Saturday, so I'm busy as shizzle), but I'll quickly touch on a few points. Sorry to reference Wikipedia, but it's the quickest option for me at the moment.

I don't think that's how it works, reproductive isolation is a consequence of adaptation, it is not a strategy towards isolation. As I see it isolation begins a mere function of behavior, which in turn allows opportunity for true genetic divergence.

That is how it works, really. Two sympatric or parapatric populations will become reproductively isolated if interbreeding between them imparts a disadvantagous result on one (or both). These mechanisms can be pre- or post-zygotic, and either can develope first. See this link: Reproductive Isolation. Selection serves to strengthen species boundaries over time.

I still say you have this wrong, genetic frequency only increases when there is a conferred advantage. and

This would not be the case unless there was some advantage specific to the mtDNA. Otherwise it would remain a very rare variant. I think your assumptions here are based on your view that "neutral mutation (i.e. tongue color) will necessarily increase in frequency until it reaches mathematical equilibrium with the alternatives". As I've said I believe this to be dead wrong and until I see it proven otherwise we'll just have to agree to disagree on this one.

In an example, let's say that a mutation takes place during meiosis that makes a neonate milk's tongue black instead of the usual red, and that black is dominant to red. If the mutation causes no other deleterious effects, and the animal lives to reproduce, half of its offspring will then have black tongues, and the frequency of the "black tongue" gene has just increased many times.

The section called "The effect of mutation" in the following link should provide mathematical support for my position.Gene frequency.

People are saying that because there is no mtDNA evidence of crossing that it didn't / doesn't happen.

There is both mtDNA and nDNA evidence to suggest that there is/has been no gene flow between the two forms. Could further evidence be found that refutes that and suggests that the two forms are conspecific? Sure! But based on the work of Pyron and Burbrink (2009, previously cited), in which they analyzed 8, 294 base pairs of nuclear and mitochondrial DNA nucleotides, it appears that elapsoides is closer to zonata than triangulum.

Crossings between a generalist and a specialist do not have the same effect in that the influence is detrimental to the specialist. As such nature is going to select against the crosses in specific niches eventually eradicating any genetic markers. For this reason looking for Ltt markers in Lte is a dead ended search. if you want to see evidence you need to look for the opposite Lte markets in Ltt as these would have the greatest chance to persist.

That selection you reference is going to help reinforce the boundaries between the forms and the evolution of reproductive barriers to prevent genetic pollution of the specialized form. No?

Here's a link from Berkely's Evolution Lab (woo hoo, not Wikipedia!) that you might like: More on Reproductive Isolation.

I've really ejoyed this discussion! I wish I could continue, but I'm out of time. I'll probably be out for the next week or so. I'll probably check in, but won't be able to respond.

Off to prep. for the wedding! Wish me luck!
-Cole

Good luck and congrats!
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I'm not sure that you fully represented Harpers work though those are his conclusions. As I recall, there was some evidence of integration with temporalis which was called "historic hybridization". The interesting thing is Harper is also making a good case that temperalis are in fact relic populations of syspila so..... if elapsoidies can integrate / hybridize with temporalis on the coastal plains why not also with the syspila in it's historic range?

My take is that these forms act as seperate species when the environment is stable but not during times of rapid change (such as what allowed and terminated syspila's eastward expansion). Call it integration or hybridization if you will but nature periodically finds ways to shuffle the deck to ensure enough genetic variety to survive environmental transitions.

In the case of elapsoides and amura crossing, I've seen animals from the eastern portion of amura's range posted here that look to have elapsoides influence. Keep in mind that if a male elaps breeds to a female amura, the interaction isn't going to be seen from an analysis of the mtDNA.
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“Nothing is at last sacred but the integrity of your own mind.” Emmerson

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Tony said,
In the case of elapsoides and amura crossing, I've seen animals from the eastern portion of amura's range posted here that look to have elapsoides influence.

Might you be referring to these animals from along the Gulf Coast?

(NOT my photos)

Other than red in the head cap and a very bright pattern, I see nothing morphologically that speaks of elapsoides. The head shape and size, in conjunction with body proportions, appear to be 100% triangulum to me. Thoughts?

Tony said,
Keep in mind that if a male elaps breeds to a female amura, the interaction isn't going to be seen from an analysis of the mtDNA.

That's not really how intergradation takes place, though. What you've described is a hybridization event. Primary intergradation, as I've detailed before, is the nondifferentiation between two "forms" along their zone of contact. This can be broad or narrow, depending on many factors (generally directional selection).

Secondary intergradation (closer to what you're describing) is where two allopatric populations come back into contact with one another. Genetic "swamping" from both sides (assuming that no reproductive isolating mechanisms have evolved) creats a situation of genetic "chaos" for a time along the zone of contact. However, with the help of gene flow and selection, this "chaos" soon settles down. The populations will either reunite and meld together (we'd see genes from one in the other - see Harper and Pfennig, 2009 in Nature), or develop reproductive isolation and remain separate.

Prior to the work of Pyron & Burbrink and Harper & Pfennig, secondary intergradation seemed a likely hypothesis for the origin of "temporalis". It now appears that my earlier thoughts on the subject may have been erroneous.

-Cole

Those are not the one.

I am not suggesting integration at all. What I am suggesting is that the interactions we currently see between elaspoides and other forms is not independent of time and conditions on the ground. As conditions on the ground have changed over time so has the interaction.
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“Nothing is at last sacred but the integrity of your own mind.” Emmerson

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But there's a big differenc between a single event and population dynamics. Obviously (well, to you and I, anyway!) conditions change through time, and the organisms change in response to the conditions.

-Cole

Would the owner of those pictures please call me and let me make an offer? Good lord...!
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those pics.....ball$.....whose got those snakes?????......ROAD TRIP.....that's the type of examples i was asking for.....jeff....i drink....A LOT.....plus who knows what residual chemicals are left in my tissues.....WHOA

Hello everyone,

I'm new to this forum, but Bob A and Cole know me from another forum where we've had several temporalis discussions.

Cole, could you provide the full citation for the 2008 Harper and Pfennig Nature article? I'd like to see where they sampled. There are a couple individuals posted on a certain website from St. Mary's and Wicomico that just don't look like "pure" syspila to me.

Thanks in advance.

Brandon

The main reason I dont buy the syspila arguement is that their head shape is more similar(though shorter) to LTT. The NC populations as well as some in St.Marys co. have the more narrowed and thinner head resembling LTE. It is a fossorial adaptation. Further, coastals arent as much a "rock" snake as LTS even with them within their habitat. I'd also like to see the samples and sample size to get some idea whether or not it deserves another look.

Here's a pic of a Richmond Co., Nc. '07 male. On a side note, I just bought an
iMac and I'm unable to post the three photos by holding the control button.
Does anybody know a way around this for Macs?
Thanks,
-Phil

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Work is the curse of
the drinking class!