Re-lumping of Common & GW Teal (2 Viewers)

[Jim LeNomenclatoriste]

Should the flavirostris taxon continue to be recognized?

 

[pbjosh]

'Good species' of ducks hybridize all the time.
Do you really believe that the levels of gene flow that they identified here are in any way unusual -- i.e., higher than between members of the Anas platyrhynchos complex, between the two species of Spatula teals, or between the different species of Mareca ?
Are the numbers of A. crecca x A. carolinensis hybrids reported in eBird really that 'jaw-dropping' ? We have more records of Branta leucopsis x B. canadensis hybrids in Belgium alone than there are records of hybrid teals in eBird in the entire world. A. rubripes readily hybridize with A. platyrhynchos when they reach this side of the pond; one single female on the Scilly Islands is known to have produced 22 first-generation hybrids over the years. Should we conclude that these "are not biological species" ?

Good data points - perhaps you should submit a comment to SACC and to NACC if you care noting this?

And also gets, a bit, to the philosophical point of what is a species as it is a purely human construct and this pair has been debated ad infinitum. At some point, if most birders/humans recognize them as two species / two different things, and the taxonomy is on the fence, coming down in favor of how humans / lay people recognize them is sage as that keeps the definition of a species aligned with what is "common sense" for humans?

 

[l_raty]

And also gets, a bit, to the philosophical point of what is a species as it is a purely human construct and this pair has been debated ad infinitum. At some point, if most birders/humans recognize them as two species / two different things, and the taxonomy is on the fence, coming down in favor of how humans / lay people recognize them is sage as that keeps the definition of a species aligned with what is "common sense" for humans?

Completely agree with this.
But pragmatism and species-level taxonomy do not frequently go hand in hand, in my experience. (Unfortunately.)

 

[cajanuma]

Good data points - perhaps you should submit a comment to SACC and to NACC if you care noting this?

And also gets, a bit, to the philosophical point of what is a species as it is a purely human construct and this pair has been debated ad infinitum. At some point, if most birders/humans recognize them as two species / two different things, and the taxonomy is on the fence, coming down in favor of how humans / lay people recognize them is sage as that keeps the definition of a species aligned with what is "common sense" for humans?

I agree with this quite a bit, at some point the subjective element of what "feels" like a species should be brought into play for these borderline cases. But it is very subjective: for example, to me Myrtle and Audubon's Warblers "feel" like two different things, as do Mallard and American Black Duck, or Golden-winged and Blue-winged Warblers. But Green-winged and Common Teal just feel like the same thing to me, so we're back to square one in terms of achieving a consensus.

 

[l_raty]

But Green-winged and Common Teal just feel like the same thing to me

What are your feelings about Mareca penelope vs. M. americana ?
Peters et al 2005 found that the mtDNA of M. americana makes it sister to the morphologically more distinct South American M. sibilatrix, just like it makes A. carolinensis sister to the morphologically more distinct South American A. flavirostris; a minority of M. penelope in this study, however, had M. americana-like haplotypes. In the same study, the CHD1Z sequences of M. penelope made this taxon paraphyletic relative to the two American taxa--some birds formed a basal cluster, others had sequences closer to those of the American taxa. Overall, this is clear suggestion of gene flow from M. americana into M. penelope.

• The more "derived" part of the "polytomy" includes all crecca-nimia, plus two carolinensis from the far-western AK Peninsula, where introgression is plausible. Note that the basal-most sample in this more "derived" part (crecca, Shemya Is./DDG1732) had a carolinensis haplotype, and is also the sample that ended up among carolinensis in Fig. 4 -- this (assuming that it was not merely ID'd on range -- i.e., that it was a male and really looked like crecca) must have been of hybrid origin.

I find it interesting that DDG1732 'became' a carolinensis at some point between the publication of the bioRxiv preprint and that of the final paper...

(This suggests the ID of the samples may not be overall very solid. The re-identification of this single bird apparently resulted in the gene flow between crecca and carolinensis being reduced to about the half of what it was in the preprint, and the estimated 'time since contact' being more than doubled. Should one single other bird in the data set be, e.g., a F1 hybrid, this would more than likely have affected the results dramatically. This makes the fact that all the crecca / nimia / carolinensis samples came from locations not very distant from the contact zone (Alaska and far-eastern Russia) all the more disturbing.)

 

[jts1882]

I agree with this quite a bit, at some point the subjective element of what "feels" like a species should be brought into play for these borderline cases. But it is very subjective: for example, to me Myrtle and Audubon's Warblers "feel" like two different things, as do Mallard and American Black Duck, or Golden-winged and Blue-winged Warblers. But Green-winged and Common Teal just feel like the same thing to me, so we're back to square one in terms of achieving a consensus.

Makes me think of the expression, If it looks like a duck, swims like a duck and quacks like a duck, then it probably is a duck species.

 

[Kirk Roth]

I agree with this quite a bit, at some point the subjective element of what "feels" like a species should be brought into play for these borderline cases. But it is very subjective: for example, to me Myrtle and Audubon's Warblers "feel" like two different things, as do Mallard and American Black Duck, or Golden-winged and Blue-winged Warblers. But Green-winged and Common Teal just feel like the same thing to me, so we're back to square one in terms of achieving a consensus.

I think that is precisely the problem. Mottled, Mexican, and Am. Black Duck "feel" pretty similar too. But they aren't lumped because people "feel" the Mexican taxon should be given equal measure with the others and that preserving status quo for those species "feels" good too. This despite that Mexican "felt" instead like a Mallard subspecies for a long time. And that because it was "felt" that the hybridization "felt" like too much and we "felt" that BSC in ducks "should" work the same as in other birds. And on and on.

Feels like a slippery slope to me!

 

[Kirk Roth]

Makes me think of the expression, If it looks like a duck, swims like a duck and quacks like a duck, then it probably is a duck species.

...unless, of course, it is a whistling duck.

 

[cajanuma]

I think that is precisely the problem. Mottled, Mexican, and Am. Black Duck "feel" pretty similar too. But they aren't lumped because people "feel" the Mexican taxon should be given equal measure with the others and that preserving status quo for those species "feels" good too. This despite that Mexican "felt" instead like a Mallard subspecies for a long time. And that because it was "felt" that the hybridization "felt" like too much and we "felt" that BSC in ducks "should" work the same as in other birds. And on and on.

Feels like a slippery slope to me!

I guess my broader point is that there's no "right answer" in many of these cases. I think the case for splitting Audubon's and Myrtle Warblers is just as valid as the case for lumping them, and there are many other such examples. Which is why I'm not crazy about the idea of a unified taxonomy, I'd rather have several lists that reflect different viewpoints/approaches.

 

[pbjosh]

Feels like a slippery slope to me!

It very much is, but these are the hardest cases for science to adjudicate with genuine full-stop answers. I don't think it's exactly the same as wanting to split Western Yellow Wagtail or Coal Tit because of regional variation (though that variation is ALSO interesting to me).

 

[MJB]

I guess my broader point is that there's no "right answer" in many of these cases. I think the case for splitting Audubon's and Myrtle Warblers is just as valid as the case for lumping them, and there are many other such examples. Which is why I'm not crazy about the idea of a unified taxonomy, I'd rather have several lists that reflect different viewpoints/approaches.

My view is that it is wholly admirable to keep such examples prominently in view and not force the outcome into the one species or two species category. Maintaining the 'don't know for certain' assessment by definition means that any unified taxonomy would have numerous examples as exceptions.
MJB

 

[THE_FERN]

I guess my broader point is that there's no "right answer" in many of these cases. I think the case for splitting Audubon's and Myrtle Warblers is just as valid as the case for lumping them, and there are many other such examples. Which is why I'm not crazy about the idea of a unified taxonomy, I'd rather have several lists that reflect different viewpoints/approaches.

Probably I've made this point before (sorry). Having different taxonomies is important when testing ecological or other patterns.

If your relationship holds up under various reasonable variant taxonomies then it's likely robust and a "real" thing. If there's only one taxonomy you lose this important robustness test.

Adding random noise to the phylogeny isn't the same because some bits will be well supported by all parties. Here, the variations incorporate reasonable but differing views under current knowledge. Adding noise might just add nonsense

 

[Peter Kovalik]

Proposal (986) to SACC

Split Anas crecca (Green-winged Teal/Common or Eurasian Teal) into two species: A. crecca (Common Teal or Eurasian Teal) and A. carolinensis (Green-winged Teal)

DID NOT PASS