Icteridae (3 Viewers)

[Peter Kovalik]

Proposal (944) to SACC

Recognize Agelasticus atroolivaceus as a separate species from Agelasticus cyanopus

DID NOT PASS

 

[Peter Kovalik]

Proposal (947) to SACC

Split Bronze-brown Cowbird (Molothrus armenti) from Bronzed Cowbird (M. aeneus)

DID NOT PASS

 

[albertonykus]

Walsh, J., S.M. Billerman, B.G. Butcher, V.G. Rohwer, D.P.L. Toews, V. Vila-Coury, and I.J. Lovette (2023)
A complex genomic architecture underlies reproductive isolation in a North American oriole hybrid zone
Communications Biology 6: 154
doi: 10.1038/s42003-023-04532-8

Natural hybrid zones provide powerful opportunities for identifying the mechanisms that facilitate and inhibit speciation. Documenting the extent of genomic admixture allows us to discern the architecture of reproductive isolation through the identification of isolating barriers. This approach is particularly powerful for characterizing the accumulation of isolating barriers in systems exhibiting varying levels of genomic divergence. Here, we use a hybrid zone between two species—the Baltimore (Icterus galbula) and Bullock’s (I. bullockii) orioles—to investigate this architecture of reproductive isolation. We combine whole genome re-sequencing with data from an additional 313 individuals amplityped at ancestry-informative markers to characterize fine-scale patterns of admixture, and to quantify links between genes and the plumage traits. On a genome-wide scale, we document several putative barriers to reproduction, including elevated peaks of divergence above a generally high genomic baseline, a large putative inversion on the Z chromosome, and complex interactions between melanogenesis-pathway candidate genes. Concordant and coincident clines for these different genomic regions further suggest the coupling of pre- and post-mating barriers. Our findings of complex and coupled interactions between pre- and post-mating barriers suggest a relatively rapid accumulation of barriers between these species, and they demonstrate the complexities of the speciation process.

 

[albertonykus]

Capainolo, P., U. Perktaş, C. Elverıcı, and M.D.E. Fellowes (2023)
Subspecies limits based on morphometry and mitochondrial DNA genomics in a polytypic species, the common grackle, Quiscalus quiscula
Biological Journal of the Linnean Society (advance online publication)
doi: 10.1093/biolinnean/blad009

Nearctic migratory songbirds have demonstrated low levels of genetic differentiation and weak phylogeographical structure in mitochondrial DNA lineages compared with resident species. The common grackle, Quiscalus quiscula, is a widespread, partially migratory, North American icterid composed of three currently recognized subspecies. In this study, mensural characters (external and skeletal measurements) and the complete mitochondrial genome together with two mitochondrial genes, Cytb and ND2, were used to investigate subspecific differentiation and demographic history of the common grackle. The results showed substantial variation in body size among subspecies, mostly distributed between the ‘Florida grackle’, Quiscalus quiscula quiscula, and the two other subspecies. Analysis of mitochondrial DNA indicated low levels of genetic variation, but we found distinct haplotypes in Florida that form a clade in the phylogenetic tree. This suggests that the nominate subspecies in Florida is a distinct evolutionary unit. The sharing of haplotypes among the other subspecies (Quiscalus quiscula versicolor and Quiscalus quiscula stonei) in the north suggests high levels of gene flow, making the status of these two subspecies equivocal. Gene flow between nominate Q. q. quiscula, Q. q. versicolor and putative Q. q. stonei is probably attributable to historical changes in distribution and abundance following climate change events. We therefore recognize only two subspecies in the common grackle complex.

 

[Xenospiza]

Capainolo, P., U. Perktaş, C. Elverıcı, and M.D.E. Fellowes (2023)
Subspecies limits based on morphometry and mitochondrial DNA genomics in a polytypic species, the common grackle, Quiscalus quiscula
Biological Journal of the Linnean Society (advance online publication)
doi: 10.1093/biolinnean/blad009

They completely gloss over the colour differences. With the minimal genetic work (who only checks mtDNA nowadays?): a disappointing article.

 

[Mysticete]

They completely gloss over the colour differences. With the minimal genetic work (who only checks mtDNA nowadays?): a disappointing article.

I've always heard that the differences between Bronzed and Purple Common Grackles is largely clinal with a large area of overlap, which might suggest that subspecies lack reliable diagnostic differences to sort birds into either form. Certainly their its not like there is a major biogeographic barrier separating the mixing of the two forms.

 

[Kirk Roth]

I've always heard that the differences between Bronzed and Purple Common Grackles is largely clinal with a large area of overlap, which might suggest that subspecies lack reliable diagnostic differences to sort birds into either form. Certainly their its not like there is a major biogeographic barrier separating the mixing of the two forms.

The barrier is the Appalachian mountains, although it is a porous boundary.

During my lifetime, there has been a noticeable philosophical shift in the way subspecies are often defined. I grew up with the understanding that a classic "Ernst Mayr" subspecies involves integration with other subspecies - in fact that is a defining trait separating them from full species. It seems that among several taxa the newer framework is that a "good" subspecies must not intergrade with others, making the distinction between "new concept" subspecies and a phylogenetic species somewhat blurred (so to speak) in my opinion.

The comment about color differences begs the question about the next obvious problem with this philosophy: if purple and bronzed Common Grackles get "lumped" under the same trinomial, how does a researcher refer to each taxa. Are they color morphs? Types? Varietals? Do they even get a name?

 

[Xenospiza]

I've always heard that the differences between Bronzed and Purple Common Grackles is largely clinal with a large area of overlap, which might suggest that subspecies lack reliable diagnostic differences to sort birds into either form. Certainly there its not like there is a major biogeographic barrier separating the mixing of the two forms.

I reached that conclusion by looking at the pictures. However, a few years ago I saw work on Bluethroat populations where the blue throats had been compared spectrographically. Quite a straightforward procedure on specimens and the iridescent colours won't fade.

During my lifetime, there has been a noticeable philosophical shift in the way subspecies are often defined. I grew up with the understanding that a classic "Ernst Mayr" subspecies involves integration with other subspecies - in fact that is a defining trait separating them from full species. It seems that among several taxa the newer framework is that a "good" subspecies must not intergrade with others, making the distinction between "new concept" subspecies and a phylogenetic species somewhat blurred (so to speak) in my opinion.

The comment about color differences begs the question about the next obvious problem with this philosophy: if purple and bronzed Common Grackles get "lumped" under the same trinomial, how does a researcher refer to each taxa. Are they color morphs? Types? Varietals? Do they even get a name?

Yes, I agree on the development subspecies seem to go through. Whatever system you use will have to deal with reality being much more complex!

 

[Mysticete]

I reached that conclusion by looking at the pictures. However, a few years ago I saw work on Bluethroat populations where the blue throats had been compared spectrographically. Quite a straightforward procedure on specimens and the iridescent colours won't fade.

I think the issue is, IIRC, there are birds which are more ambiguous, where it's not obvious. And birds which seem to have the morphology of one form but the genetics of another. IF Common grackles form a cline that obviously the ones at either end should be easy to separate.

Granted, its been a long time since I have spent much time thinking about these differences, so maybe I am misremembering.

 

[Mysticete]

The barrier is the Appalachian mountains, although it is a porous boundary.

During my lifetime, there has been a noticeable philosophical shift in the way subspecies are often defined. I grew up with the understanding that a classic "Ernst Mayr" subspecies involves integration with other subspecies - in fact that is a defining trait separating them from full species. It seems that among several taxa the newer framework is that a "good" subspecies must not intergrade with others, making the distinction between "new concept" subspecies and a phylogenetic species somewhat blurred (so to speak) in my opinion.

The comment about color differences begs the question about the next obvious problem with this philosophy: if purple and bronzed Common Grackles get "lumped" under the same trinomial, how does a researcher refer to each taxa. Are they color morphs? Types? Varietals? Do they even get a name?

I mean, a lot of people don't even believe subspecies should exist, and that anything with diagnostic differences matching some genetic differentiation should just be a species. Remsen has made an argument, in a paper that I think was discussed in this forum, that phylogenetic species should be considered subspecies, which would require there to be an element of diagnosability, genetic and geographic differentiation, and monophyly. Species should then be considered biological species, so they would have the above traits + inability to breed with close relatives. That makes the most sense to me, although you then still have to figure out how different something is to be diagnosable.

Not helping matters is the fact that subspecies are largely neglected, so there is a whole swath of them on the books that were named over trivial differences that would almost certainly not be found to be significantly different.

 

[njlarsen]

I mean, a lot of people don't even believe subspecies should exist, and that anything with diagnostic differences matching some genetic differentiation should just be a species. Remsen has made an argument, in a paper that I think was discussed in this forum, that phylogenetic species should be considered subspecies, which would require there to be an element of diagnosability, genetic and geographic differentiation, and monophyly. Species should then be considered biological species, so they would have the above traits + inability to breed with close relatives. That makes the most sense to me, although you then still have to figure out how different something is to be diagnosable.

Not helping matters is the fact that subspecies are largely neglected, so there is a whole swath of them on the books that were named over trivial differences that would almost certainly not be found to be significantly different.

you are taking about a special issue from AOU (before they got that name) on species and subspecies determination, where some papers argued that subspecies were impossible to define and others tried to define limits of diagnosability for when more than one subspecies should be recognized within a species.

With the current forum setup, I do not find it easy to search for the thread discussing this topic.
Niels

 

[Kirk Roth]

I mean, a lot of people don't even believe subspecies should exist, and that anything with diagnostic differences matching some genetic differentiation should just be a species. Remsen has made an argument, in a paper that I think was discussed in this forum, that phylogenetic species should be considered subspecies, which would require there to be an element of diagnosability, genetic and geographic differentiation, and monophyly. Species should then be considered biological species, so they would have the above traits + inability to breed with close relatives. That makes the most sense to me, although you then still have to figure out how different something is to be diagnosable.

At its most base level, the job of taxonomy is to sort through those diagnosable differences - and if we're being honest a taxonomic "hierarchy" needs to adjust to those observed differences, not the other way around. So for birds, if we do away with subspecies and call anything with a difference a species... then we need another name to designate that level of taxonomy where species stop breeding with each other. With tongue-in-cheek, I'm sure someone could propose a trinomial for phylogenetic species and a binomial for biological species and the problem is solved!

The biological species concept, with allocation for subspecies, makes a lot of sense for birds and their biology. Just like the taxonomy of call types makes sense for Red Crossbills and a taxonomy of color morphs makes sense for various Buteos. Those taxonomies don't really translate to penguins and wrens and what have you. Subspecies might not make much sense for taxa like freshwater fish. And I've been told by a herpetologist that the BSC doesn't do a great job for reptiles and amphibians, although I'm not sure I could explain his reasoning. But I do believe that there is no "one size fits all" taxonomy, and if our goal is to have a language to describe the natural world, that language will need to be as adaptive as the subjects are diverse.

 

[Mysticete]

The biological species concept, with allocation for subspecies, makes a lot of sense for birds and their biology. Just like the taxonomy of call types makes sense for Red Crossbills and a taxonomy of color morphs makes sense for various Buteos. Those taxonomies don't really translate to penguins and wrens and what have you. Subspecies might not make much sense for taxa like freshwater fish. And I've been told by a herpetologist that the BSC doesn't do a great job for reptiles and amphibians, although I'm not sure I could explain his reasoning. But I do believe that there is no "one size fits all" taxonomy, and if our goal is to have a language to describe the natural world, that language will need to be as adaptive as the subjects are diverse.

BSC works really well with birds overall, because as it turns out there songs and visual displays are easy for humans to study and distinguish. Chemical signaling as in salamanders, not so much. Also because birds are really good at dispersal, I think there is more need to evolve reproductive isolation. A lot of other critters basically will fill the area of appropriate habitat they can reach, and it might be hundreds of thousands of years before they ever see another closely related population, because they can't simply fly over the river/ridge/stretch of desert/etc.

 

[Peter Brick]

Who is the authority for the family Icteridae?

Bock 1994 p. 156 and 264 in his History and Nomenclature of Avian Family-Group Names (book available here) credits Vigors 1825 "Observations on the natural affinities that connect the orders and families of birds" (without specifying a page number). But although Vigors mentions the genus Icterus he seems to place it in the family Sturnidae - see page 447 available here

Vigors again discusses Icterus in his "On the arrangement of the genera of birds" available here but again doesn't mention a family or subfamily group.

 

[l_raty]

Who is the authority for the family Icteridae?

Bock 1994 p. 156 and 264 in his History and Nomenclature of Avian Family-Group Names (book available here) credits Vigors 1825 "Observations on the natural affinities that connect the orders and families of birds" (without specifying a page number). But although Vigors mentions the genus Icterus he seems to place it in the family Sturnidae - see page 447 available here

Vigors again discusses Icterus in his "On the arrangement of the genera of birds" available here but again doesn't mention a family or subfamily group.

Vigors 1825 in your second link -- as a subfamily 'Icterina', on p. 184 : v.2=no.5-8 (1825:Apr.-1826:Apr.) - The Zoological journal - Biodiversity Heritage Library

 

[Peter Brick]

Oops - I needed to look on the next page. Many thanks Laurent.