Content Author Object Flagger Flag Created Reason Resolved by Resolution
Copperheads, Cottonmouths, and Cantils (Genus Agkistrodon) bouteloua Thu, 11 Jul 2019 18:36:39 +0000

taxonomic updates

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Agkistrodon contortrix and A. laticinctus
A. contortrix laticinctus --transferred to--> A. laticinctus laticinctus (taxon change)
A. contortrix pictigaster --transferred to--> A. laticinctus pictigaster (taxon change)
A. contortrix sensu lato --split into--> A. contortrix sensu stricto, A. laticinctus, and hybrid (taxon change)

Needs prior to committing A. contortrix taxon changes:
1. Text description of reason for each change
2. Atlas and range for A. contortrix sensu stricto, A. laticinctus, and hybrid

Review of whether the above list of changes, ranges, and atlases are accurate/complete

---------------AND

Agkistrodon conanti and A. piscivorus
A. piscivorus conanti --elevated to--> A. conanti (taxon change)
A. piscivorus sensu lato --split into-->A. piscivorus sensu stricto and A. conanti (taxon change)
A. piscivorus piscivorus and A. piscivorus leucostoma --lumped into--> A. piscivorus sensu stricto (taxon change)

Needs prior to committing A. conanti/piscivorus taxon changes:
1. Text description of reason for each change
2. Atlas (and ideally range too) for A. laticinctus
3. Atlas (and ideally range too) for A. piscivorus sensu stricto
4. Atlas (and ideally range too) for A. conanti

Review of whether the above list of changes, ranges, and atlases are accurate/complete

Can someone please help with this?

(comment edited)

Posted by bouteloua over 1 year ago (Flag)
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Sorry, not me. I am not willing to engage in reptile taxonomy management. Quite bluntly, I'm not interested in getting engaged in the constant fights that go on within it.

Posted by cmcheatle over 1 year ago (Flag)
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Sorry, @cmcheatle, but can you elaborate? I didn't know there were "fights" going on.

EDIT: @bouteloua I would be happy to help, but @loarie is the only taxon curator for reptiles right now.

Posted by bobby23 over 1 year ago (Flag)
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Most of the needs listed above don't require being a taxon curator.

(And let's keep this thread focused on the taxonomy)

Posted by bouteloua over 1 year ago (Flag)
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@bobby23 - there is a long-standing and still ongoing pattern of pretty dire behaviour among some of the more passionate members of the reptile community regarding iNat taxonomy, practices and even directed at individuals.

I don't think the issue deserves additional oxygen or focus to continue to drive it, but if you really need examples, I can send them to you privately.

I personally am simply not interested in being dragged into the stuff, so will focus my volunteered curating time elsewhere.

Posted by cmcheatle over 1 year ago (Flag)
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Ranges and atlases have been updated for the cottonmouths too https://www.inaturalist.org/taxon_changes/59156

Posted by bobby23 over 1 year ago (Flag)
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Oh what fun... the Burbrink & Guiher paper provided every possible reason why neither conanti nor laticinctus should be separate species, in the shape of massive zones of introgression.

Implementing this change now means that cottonmouths from a broad swath of the southeast, from southern Mississippi to southern Georgia, will now have to be called Agkistrodon sp., and ditto for copperheads all the way from E Kansas down to E Texas. For anyone who thought the ratsnakes were a mess, welcome to this clusterfudge.

An earnest suggestion: dispense with the individual species designatons for both, and just have a single category called "Cottonmouth (Agkistrodon piscivorus / conanti complex)" and "Copperhead (Agkistrodon contortrix / laticinctus complex)". At the end of the day, the vast majority of the user community simply wants to know whether it's a copperhead, or a cottonmouth.

And most of this also applies to the Vipera berus / nikolskii split.

NB: getting rid of the various subspecies (leucostoma, phaeogaster, mokasen etc.) was a valid move supported by good evidence from Burbrink & Guiher.

Posted by wolfgang_wuster about 1 year ago (Flag)
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@wolfgang_wuster what do you advise? (a) keep as is, (b) lump back together, (c) add 'complex' nodes (d) other?

Posted by loarie about 1 year ago (Flag)
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@loarie

Thanks for responding!

I would lump back together.

It corresponds to the evidence actually presented in the Burbrink & Guiher paper, which documents large intergrade zones.
I think there will be pushback against that paper before long - there are certainly papers in the works about some of the other N. American splits that show them to be ill-advised, and many of my colleagues take a dim view of this one
In terms of the iNaturalist user community, I suspect that the vast majority would prefer to just know whether they had a copperhead or a cottonmouth...

I should add for the record that the Burbrink & Guiher paper had lots of good information and data in it, it was innovative and rigorous in many ways, and I agree with the sinking of the old ssp., especially of copperheads. It's just that I (and many others) don't feel that the data presented really support species status. When you have a hybrid zone between A. piscivorus and A. conanti that's as large as the entire distribution of A. conanti, then I find it hard to argue that these are independent evolutionary units... but I don't want to convey the impression that the paper was bad from beginning to end - not at all.

Posted by wolfgang_wuster about 1 year ago (Flag)
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and your suggesting that both copperhead and cottonmouth should be monotypic (ie no ssp)?

curious what others think

Posted by loarie about 1 year ago (Flag)
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No, conanti and laticinctus should be listed as subspecies - they are clearly distinct entities, albeit with wide intergrade zones. But for those, we can then simply leave out ssp. designations and still call them A. contortrix or A. piscivorus while staying within the system.

Posted by wolfgang_wuster about 1 year ago (Flag)
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My preference would be to follow our external taxonomic authority or at least contact them before making additional changes. I would also prefer that we use "complex" designations conservatively (in other words, as scarcely as possible), but this discussion should probably include more users/curators who are familiar with snake taxonomy (as oppose to me, who is not).

Posted by bobby23 about 1 year ago (Flag)
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This is a tough one: iNaturalist clearly should not be a taxonomic innovator, but at the same time, the current Reptile Database classification is difficult to reconcile with the way that iNaturalist works, as well as being contentious within herpetology itself.

As a basis for discussion, here is my perception of the pros and cons of different options:

Treat copperheads and cottonmouths as single species, with laticinctus and conanti as subspecies, respectively.
Pros: probably best reflects genetic evidence, esp. for cottonmouths; gives single species-level ID that many users will most want ("It's a cottonmouth!"); no complex explanation needed.
Cons: goes against Reptile Database and the latest published research paper (Burbrink & Guiher); could be seen as political or a snub against the authors of the latter.

Call both copperheads and cottonmouth complexes - so Copperhead (Agkistrodon contortrix / laticinctus complex) and Cottonmouth (Agkistrodon piscivorus / conanti complex). This could be applied either across the entire range of both, or restricted to the hybrid zone while recognising the laticinctus and conanti as full species.
Pros: Less political than keeping them as single species; reflects complexity of situation
Cons: complicated. If used only for specimens from hybrid zones, it loses the overall information many will want ("It's a cottonmouth!"), and it will complicate data searches. If used for the entirety of the range of each complex, it will lose the substructuring into the lineages piscivorus and conanti or contortrix & laticinctus, respectively.

Accept conanti and laticinctus as species, call specimens from introgression zones hybrids (piscivorus x conanti, contortrix x laticinctus)
Pros: in keeping with Reptile Database and latest revision paper
Cons: many would not regard it as consistent with the evidence; loses sight of wood for the trees ("It's a cottonmouth"); loses clear assignation of many observations across large areas to an unambiguous species; will complicate data searches.

Accept conanti and laticinctus as species, classify specimens from introgression zones simply as Agkistrodon sp., as implemented by default in the initial taxon split
Pros: none
Cons: untenable - we do know whether we are looking at a copperhead, cottonmouth or cantil!

I hope that helps stimulate thought and discussion. More views would definitely be useful.

Posted by wolfgang_wuster about 1 year ago (Flag)
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thanks for that framework - I think in terms of disruption they are already ordered properly with 1 being the most disruptive and 4 being the least disruptive.

I take your point that if people can't tell 2 nodes apart, and they form a clade its useful to have a way of grouping them for practical iNat purposes if nothing else. I also agree that the researcher community shouldn't split monophyletic clades that intergrade and lack clear boundaries.

I think I'm personally most in favor of 2 because it will provide nodes for people to access the combined 'cottonmouth' and 'copperhead' concepts (and an anchor for potential future more disruptive lumps) but doesn't require deviating from RD or another disruptive taxon change (We can also make it so that IDs that were reassigned to Akistrodon sp. in the recent splits are reassigned to these nodes to try to mitigate damage done)

Posted by loarie about 1 year ago (Flag)
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I would argue that option 1 is the least disruptive - we return to the status quo ante and pretend the last 72 hrs didn't happen ;)

In the meantime, what seems to be happening out there is the gradual implementation of option 3 by the user community, with specimens from the intergrade zones being assigned to hybrid status. Democracy at work, I suppose.

Posted by wolfgang_wuster about 1 year ago (Flag)
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@wolfgang_wuster this can't really be reverted so option 1 would require another big taxon change touching every identification, making them non-current and making new ones etc. Are you opposed to option 2?

Posted by loarie about 1 year ago (Flag)
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Given where we are and what you wrote, I guess either option 2 or option 3 are the best we can do (I am not clear as to whether these have different implications for searchability).

Posted by wolfgang_wuster about 1 year ago (Flag)
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Ok I'll replace with complexes (option 2) I'll also replace this hybrid with a complex see https://www.inaturalist.org/flags/443772

Posted by loarie about 1 year ago (Flag)
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Yes, definitely implement the same treatment for copperheads and cottonmouths.

Posted by wolfgang_wuster about 1 year ago (Flag)
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I agree with the species complex option being the best available solution in those areas of overlap. It doesn't make any implication as to the possibility of individuals being hybrids.

The same policy should probably be applied to Lampropeltis holbrooki and splendida as well.

Posted by sandboa about 1 year ago (Flag)
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Looks like I was late to the party, but as a curator of a major natural history collection of reptiles and amphibians and also a major contributor of tissues the the burbrink and guiher paper we will not be making taxonomic changes within our collection based on this paper. I agree with Wolfgang's comments that we should be able to call "hybrids" A. laticinctus/contortrix or A. conanti/piscivorus.

Posted by toby about 1 year ago (Flag)
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I closed this related flag to consolidate the conversation here https://www.inaturalist.org/flags/443772

Posted by loarie 12 months ago (Flag)

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