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Copperheads and Cottonmouths - mDNA work published
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by Cro on August 1, 2008
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The preliminary work that will eventually change the names of Copperheads and Cottonmouths as you now know them has been published.
http://www.cnah.org/pdf_files/1024.pdf
This research used mDNA to establish 3 Copperhead populations in the United States. These will be the Eastern population, the Central population, and the Western population.
The research also established 2 Cottonmouth populations, Continental population, and the Florida population.
More extensive research using nuclear DNA will be needed to species status within these groups.
What this means is that we will lose some of the sub-species associated with these snake populations, and some of these snakes will be elevated to species status, and some might remain sub-species. That will be based on gene flow between the populations, and if the populations are distinct or clinal.
Nomenclatural rules will determine which names came first, and those will mostly remain, and some of the latter sub-specific names will be dropped.
I will guess that we will wind up with Agkistrodon contortrix, laticintus, and pictigaster, for the Copperheads, and Agkistrodon piscivorus, and conanti, for the Cottonmouths, but you never know. Will be interesting to see what the bean counters come up with.
Looks like a lot of the Field Guides will require major revisions in the near future.
Best Regards John Z
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RE: Copperheads and Cottonmouths - mDNA work publi
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by theemojohnm on August 1, 2008
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This upsets me for some strange reason. LOL...
My favorites are the Agkistrodon! Now I have to learn a bunch of goofy latin names all over again?!!!
LOL...
~John.
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RE: Copperheads and Cottonmouths - mDNA work publi
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by Cro on August 1, 2008
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John, you might as well get used to it.
The new mDNA and Nuclear DNA will cause a lot of upset over the next few years.
However, when it is all said and done, a lot of populations of Reptiles and Amphibians will be much better understood, and more stable. In the long run, it should be a good thing.
A lot of animal classifications and relationships that were poorly known will be much better understood.
Unfortunatly, it is no longer good enough to look at dark copperhead from the mountains, or a light copperhead from the southlands, and call them different sub-species. Using coloration, scale counts, etc., worked for a long time. However, science is ever changing, and now, those features, while still considered, do not play as much of a role as what the animals ancestors were.
A lot of books and data bases will have to be updated, and many older books will become worthless.
You have it easy though, I have been remembering Scientific Names for over 40 years, and will have thousands of them to re-learn, LOL.
I am trying my best to learn as much as I can about this new science. It is complicated stuff, but still very interesting to learn.
Best Regards John Z
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RE: Copperheads and Cottonmouths - mDNA work publi
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by FSB on August 1, 2008
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Uh-oh, here we go again.... I have a few problems with the recent shift in emphasis to phylogenetics being the primary basis for classification, and the move away from gross appearances. Maybe I just can't handle change, but this constant reordering and renaming is getting hard on us old dogs who have to shake the sofa cushions looking for spare brain cells. I have worked diligently to make Pantherophis, Tropilodaemus and all of these new genera part of my everyday vocabulary, but it seems that every time I'm almost out of the pit, here comes another bucket-load of sand. I'm sure I'm not alone.
I found the article "Crocodiles and turtles are not reptiles? CNAH thinks so" on the home page of this site to be an interesting read. I have heard about the coming reorganization of Agkistrodon, and also about a looming merger of Pituophis with the rat snakes. DNA may not lie, but it seems to be somewhat of a case of missing the forest for the trees. I still think there is a great deal of value in distinguishing species on their obvious gross characteristics, and a bull snake is very obviously different from a rat snake, regardless of how similar the DNA might be. Can't we just satisfy ourselves with assimilating the new knowledge that these species are genetically similar without having to totally reclassify and rename them?
The snakes have not changed -- they will remain the same no matter what we call them, so why make it so hard on ourselves? Remember, a rosy boa by any other name...
I will continue to see gross differences, and similarities, in different snakes; this is part of the fascination they hold for me, and a huge part of the enjoyment I derive from them. Phylogenetics may hold that there are no canebrake rattlesnakes, but I will continue to differentiate between canebrakes and normal timbers. This is not only based on pattern and color - the shapes of their heads differ, and so do their personalities.
I'm not denying the validity of DNA analysis one bit, and the information it provides is certainly useful and interesting, but I just don't think that's all there is and that everything else should be thrown out the window because of sudden advances being made in an exciting new field. Back in the early 1980's, some of my musician friends told me that Midi technology was going to take over everything and that acoustic music was going the way of, well, "atricaudatus."
"Lose the banjo" they all said, "pretty soon keyboards are going to be able to sound just like a banjo." Well, it never happened, and I've never heard an electronically-generated banjo sound that was anything like a real banjo. In fact, the technology revolution actually created a backlash that resulted in acoustic music undergoing a resurgence in the late 1990's that has lasted to the present day. Plus, I can still play even when the power goes out, so there!
I could go on, of course, but I think the point is made.
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RE: Copperheads and Cottonmouths - mDNA work publi
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by theemojohnm on August 1, 2008
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John, now dont get me wrong, I believe this is great work. I think their are several cases where alot of the Agkistrodon in particular need to be cleared up.
I have similar feelings about the "timber" vs. "canebrake" area aswell. I have been "herping" the woods and fields of PA ever since I could walk, and in many instances I see animals that are said to be subspecies of another and have NO outawrd physical or color differences.
I also have opposite feelings ocassionly with Nerodia sipedon, the Northern Watersnake. Although in this area thats what all the specimens are...Northerns.. I see some great diversity and variety between individuals of the same area. Most of these changes are subtle and simply color differences, but in some exceptional cases, I had to pull up old documents and different Nerodia studies suspecting I had found somthing "new". I have allways though more extensive dna work should be done on several genus, and Agkistrodon being one of them. And yes, I still am extremely young compared to most of you guys here, but I to can admit that I have gotten pretty used to the classification system regarding the Agkistrodon.
I agree it is fascinating research... Its just gonna suck to be calling everything Agkistrodon onething, when they will technically be something new.. LOL..
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RE: Copperheads and Cottonmouths - mDNA work publi
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by theemojohnm on August 1, 2008
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And I'm somwhat confused about the cottonmouth, and honestly have not had time to read the report fully (unless I missed it...the font size drives my eyes nuts!).
Are they saying that all cottonmouths should be lumped into one species with only regional color variances, or are they proposing that the florida cottonmouth be further split into two subspecies???
~John.
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RE: Copperheads and Cottonmouths - mDNA work publi
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by Cro on August 1, 2008
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John, what they finally do with the Cottonmouths is still not decided.
What once was the Eastern and Western races will now all be called the Continental Cottonmouth, and will probably all be considered Agkistrodon piscivorous.
As far as the Florida race, it could go a couple of different ways. The study found that those populations had been isolated for a long time. At one time, the lower part of Florida was kind of cutt off, and was really an island. What is now the Okefenokee Swamp was filled with sea water. So, there are a lot of DNA differences between the Florida population, and the new Continental populations.
They might decide to elevate conanti to full Species status, and it would become Agkistrodon conanti, and the Continental population would be Agkistrodon piscivorous.
Or, they might leave the Continental population as Agkistrodon p. piscivorous, and the Florida population would remain Agkistrodon p. conanti.
Because of the work that Roger Conant did for Herpetology, and the naming of that snake as an honorarium for him, I am sure that they will retain that name in some way.
It is just too early to tell how this will go, as they will have to find out just how well the populations are seperated from each other, and if there is a clinal change (zone of intigradation) between the two populations, or if the two populations are distinct enough from each other to be considered seperate animals. The nuclear DNA study should determine that.
Should be fun to watch.
Best Regards John Z
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RE: Copperheads and Cottonmouths - mDNA work publi
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by theemojohnm on August 1, 2008
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John,
Wow, I agree this is very interesting and benificial. Please keep us updated if you find out any new publications or releases of the studies findings!
Honestly, if it were another genus, I probably would not be as interested, but this new research will change the classification of the first venomous species I have ever caught and kept..the northern Copperhead. The first snake that sparked my interest in venomous, and remnains a member of my favorite genus.
Thank you VERY much for the info!
I will look for updates as much as possible.
Please keep us updated if if you find any furtherance on this study sooner than me..
~John.
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RE: Copperheads and Cottonmouths - mDNA work publi
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by Cro on August 2, 2008
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The mDNA / nuclear DNA research that I really want to see, is the one that will divide the King Cobra (Ophiophagus hannah) into who knows how many different animals.
It could result in 7 to 13 distinct animals. Some would be elevated to Species, and some would be Sub-Species.
These impressive snakes range over a huge area, and very a great deal, over various parts of that range.
I wonder if WW or others are working on that one ?
Best Regards John Z
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RE: Copperheads and Cottonmouths - mDNA work publi
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by GREGLONGHURST on August 3, 2008
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Not to denigrate any of the other posters, but Fred's post a few up from this one is probably the best post I have ever seen on a snake board. Good job, Fred! Well thought out, well written, with humor thrown in.
John..thank you for starting this thread. Like Fred, I am afraid this may be taken too far, but, I agree with you that Ophiophagus is in need of some work. I'm so old I can remember when they were Naia hannah. And I remember being slightly irritated when "They" changed Natrix to Nerodia.
~~Greg~~
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