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The Fun Taxonomic History of Selasphorus flammula (1 Viewer)

TicoTyler

Tyler Wenzel
Supporter
Costa Rica
Over the the course of the last year, I've worked on revising the Birds of the World article for the Volcano Hummingbird. By far the most fascinating part of the account for me was writing about the history of its treatment as a species or two or three. I've quoted some of what I wrote there to share here:

The systematics of the southern forms of Selasphorus, including the Volcano Hummingbird, have undergone several changes since the initial descriptions were made between 1850 and 1910. The nominate flammula and subspecies torridus holotypes were collected by Smithsonian collector E. Arce on Irazú Volcano and in the Cordillera de Talamanca, respectively. Osbert Salvin used these specimens and initially described them as separate species in 1864 (flammula) and 1870 (torridus). Salvin then described a putatively new species in 1897 as Selasphorus underwoodii, which is now recognized as a hybrid between the Scintillant Hummingbird (Selasphorus scintilla) and the Volcano Hummingbird. Finally, Melbourne Carriker collected the holotype for the simoni subspecies on Poás Volcano in 1910. Initially believed to belong to Glow-throated Hummingbird (Selasphorus ardens), in consultation with French hummingbird expert Eugene Simon he described this population as a separate species and named it after Simon.

In the same 1910 paper, Carriker treated torridus as a subspecies of flammula, as these seemed to differ only in male gorget color. Ridgway accepted most of Carriker's 1910 suppositions but retained torridus as a separate species based on male gorget color as well as supposed differences in the color of the rectrices of the females. Berlioz and Slud both considered torridus to be simply a color morph of flammula rather than a distinct species or subspecies. Slud retained simoni as a separate species, but considered it possibly a subspecies of Selasphorus ardens based principally on color differences rather than detailed measurement. His conclusion was likely due to not examining their morphology in sufficient detail combined with a small sample size. Wetmore placed torridus as a subspecies of flammula (but did not consider the status of simoni).

Stiles' extensive work on the Selasphorus taxa clarified the species divisions to what is generally accepted today. He considered detailed aspects of morphology, particularly the shape and coloration of rectrices as well as their breeding and display behavior. This resulted in simoni and torridus being treated as subspecies of flammula. This treatment brought simoni into the Volcano Hummingbird complex and removed it from Selasphorus ardens. The taxon underwoodii, of which only one holotype is known, was determined by Stiles to be a hybrid of Selasphorus scintilla and Selasphorus flammula flammula. Further studies of breeding behavior by Clark et al. of Selasphorus scintilla and Selasphorus flammula validated Stiles' classification. Dyer and Vallely also analyzed specimens of Selasphorus ardens and Selasphorus flammula simoni and concurred with Stiles treatment as simoni being part of Selasphorus flammula and not Selasphorus ardens.

Presently, most authors treat the Volcano Hummingbird limits as being settled and recent phylogenetic studies generally supports this conclusion.
To this, I add there is still some potential uncertainty particularly around the population on Poás and Barva Volcanos which extends up into Juan Castro Blanco National Park. It has the smallest reproductive habitat available and is the most genetically distinct (I think). I found some limited genetic studies on some specimens in the LSU museum but couldn't find the localities for the specimens nor did my consultations to the paper authors receive a response in inquiring about their locations, but I believe they show some level of genetic difference between flammula/torridus and simoni (guessing that's how the specimens break down on biogeographic grounds) however my knowledge of genetics doesn't allow me to opine on the significance of these differences as to whether there is a potential for a future split or not. I think (very) long term their allopatric breeding habitats will obviously lead to speciation but in the present I'm not sure how different they are in terms of whether there is near term potential for a split. Any thoughts on the topic are welcome.

1733626404611.png
 
Over the the course of the last year, I've worked on revising the Birds of the World article for the Volcano Hummingbird. By far the most fascinating part of the account for me was writing about the history of its treatment as a species or two or three. I've quoted some of what I wrote there to share here:


To this, I add there is still some potential uncertainty particularly around the population on Poás and Barva Volcanos which extends up into Juan Castro Blanco National Park. It has the smallest reproductive habitat available and is the most genetically distinct (I think). I found some limited genetic studies on some specimens in the LSU museum but couldn't find the localities for the specimens nor did my consultations to the paper authors receive a response in inquiring about their locations, but I believe they show some level of genetic difference between flammula/torridus and simoni (guessing that's how the specimens break down on biogeographic grounds) however my knowledge of genetics doesn't allow me to opine on the significance of these differences as to whether there is a potential for a future split or not. I think (very) long term their allopatric breeding habitats will obviously lead to speciation but in the present I'm not sure how different they are in terms of whether there is near term potential for a split. Any thoughts on the topic are welcome.

View attachment 1616973
You don't include the axis in the phylogeny so we can't assess whether there's any way to tell genetic distance. However, the impression is of shallow divergence, perhaps unlikely to warrant a split (but these things are entirely subjective, arbitrary)

Contributions to opus have the advantage of not being behind a pay wall (ditto Wikipedia)
 
You don't include the axis in the phylogeny so we can't assess whether there's any way to tell genetic distance. However, the impression is of shallow divergence, perhaps unlikely to warrant a split (but these things are entirely subjective, arbitrary)

Contributions to opus have the advantage of not being behind a pay wall (ditto Wikipedia)
There were two papers I referenced, this is the full phylogeny of the clade from a 2014 paper:

1733675087474.png
And then I believe this 2017 analysis was based on the data from 2014 (See page 7).

Eventually I'll get around to updating Opus with some more info based on what I've written for BOW.
 
I am not at all sure why you consider Enrique Arcé to be a "Smithsonian collector". As Olson made very clear in his study of Batty, Arcé was trained by Osbert Salvin and sent much of his early material to his "mentor", which explains why the types of flammula and torridus are now in Tring, arriving in the then British Museum via the Salvin-Godman bequest. As Deignan (1961) reported, all of the types held in Washington DC collected by Arcé were either donated to the Smithsonian by Salvin or were hummingbirds purchased from Boucard (who may well have got some of those from Salvin!).

Selasphorus torridus Salvin, 1870, was described on the basis of multiple syntypes; there is no holotype of this name.
 
I am not at all sure why you consider Enrique Arcé to be a "Smithsonian collector". As Olson made very clear in his study of Batty, Arcé was trained by Osbert Salvin and sent much of his early material to his "mentor", which explains why the types of flammula and torridus are now in Tring, arriving in the then British Museum via the Salvin-Godman bequest. As Deignan (1961) reported, all of the types held in Washington DC collected by Arcé were either donated to the Smithsonian by Salvin or were hummingbirds purchased from Boucard (who may well have got some of those from Salvin!).

Selasphorus torridus Salvin, 1870, was described on the basis of multiple syntypes; there is no holotype of this name.

Thanks, as I was copying and pasting this over from BOW last night and cleaning up the formatting IDK why I suddenly added Smithsonian for some reason, which isn't in the BOW text. I was previous to writing this post reading something about Ridgway - Zeledón and I think I just got Smithsonian stuck in my head.
 
I am not at all sure why you consider Enrique Arcé to be a "Smithsonian collector". As Olson made very clear in his study of Batty, Arcé was trained by Osbert Salvin and sent much of his early material to his "mentor", which explains why the types of flammula and torridus are now in Tring, arriving in the then British Museum via the Salvin-Godman bequest. As Deignan (1961) reported, all of the types held in Washington DC collected by Arcé were either donated to the Smithsonian by Salvin or were hummingbirds purchased from Boucard (who may well have got some of those from Salvin!).

Selasphorus torridus Salvin, 1870, was described on the basis of multiple syntypes; there is no holotype of this name.
To address the second part separately, yes you're correct. There's a discrepancy in the text there. The introduction says that:

The nominate flammula and subspecies torridus holotypes were collected by E. Arce on Irazú Volcano and in the Cordillera de Talamanca, respectively.

However, the details for the subspecies link to the 1870 Proceedings of The Zoological Society of London where Salvin says he received six individuals. I'll see if they will let me update the introduction text to fix that.
 
To address the second part separately, yes you're correct. There's a discrepancy in the text there. The introduction says that:



However, the details for the subspecies link to the 1870 Proceedings of The Zoological Society of London where Salvin says he received six individuals. I'll see if they will let me update the introduction text to fix that.
Was able to get this fixed. Thanks for pointing it out Guy. @GMK
 
For someone who has a rudimentary understanding at best of this could you explain what you see in this paper in terms of the significance of genetic differences?

In the time-calibrated tree, the deepest node within Selasphorus flammula seems to be given an age between 200,000 and 300,000 years, which I think is quite short for populations to become distinct species.

The LSU sample numbers ("LSUMZ B19847", etc.) that are given in the trees do not seem to correspond to specimens in the LSU bird specimen collections, but appear to match records in the LSU "Tissue Collection Database" (which can be searched here).
The Selasphorus flammula tissue samples in this database are :

Genus Species State Country Material LSUMZ
SelasphorusflammulaCartago ProvinceCosta RicaLiquid Nitrogen19780
SelasphorusflammulaCartago ProvinceCosta RicaLiquid Nitrogen19794
SelasphorusflammulaChiriquÌ ProvincePanama0_C Freezer28246
SelasphorusflammulaChiriquÌ ProvincePanama0_C Freezer28253
SelasphorusflammulaChiriquÌ ProvincePanama0_C Freezer28260
SelasphorusflammulaChiriquÌ ProvincePanama0_C Freezer28261
SelasphorusflammulaChiriquÌ ProvincePanama0_C Freezer28267
SelasphorusflammulaChiriquÌ ProvincePanama0_C Freezer28268
SelasphorusflammulaChiriquÌ ProvincePanama0_C Freezer28269
SelasphorusflammulaChiriquÌ ProvincePanama0_C Freezer28280
SelasphorusflammulaChiriquÌ ProvincePanama0_C Freezer28283
SelasphorusflammulaChiriquÌ ProvincePanama0_C Freezer28293
SelasphorusflammulaChiriquÌ ProvincePanama0_C Freezer28306
SelasphorusflammulaChiriquÌ ProvincePanama0_C Freezer28313
SelasphorusflammulaChiriquÌ ProvincePanamaLiquid Nitrogen26457
SelasphorusflammulaSan JosÈ ProvinceCosta RicaLiquid Nitrogen19847
SelasphorusflammulaSan JosÈ ProvinceCosta RicaLiquid Nitrogen19883
SelasphorusflammulaSan JosÈ ProvinceCosta Ricaunknown16222
SelasphorusflammulaSan JosÈ ProvinceCosta Rica9952

Which means :

1733823532678.png

You certainly know this better than me, but my understanding is that simoni is found in prov. de Heredia (Volcán Barva) and prov. de Alajuela (Volcán Poás); if so, it was presumably not sampled.
I think that what can be seen within S. flammula in this tree is more likely to reflect individual variation, rather than anything taxonomically significant.
 
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In the time-calibrated tree, the deepest node within Selasphorus flammula seems to be given an age between 200,000 and 300,000 years, which I think is quite short for populations to become distinct species.

The LSU sample numbers ("LSUMZ B19847", etc.) that are given in the trees do not seem to correspond to specimens in the LSU bird specimen collections, but appear to match records in the LSU "Tissue Collection Database" (which can be searched here).
The Selasphorus flammula tissue samples in this database are :

Genus Species State Country Material LSUMZ
SelasphorusflammulaCartago ProvinceCosta RicaLiquid Nitrogen19780
SelasphorusflammulaCartago ProvinceCosta RicaLiquid Nitrogen19794
SelasphorusflammulaChiriquÌ ProvincePanama0_C Freezer28246
SelasphorusflammulaChiriquÌ ProvincePanama0_C Freezer28253
SelasphorusflammulaChiriquÌ ProvincePanama0_C Freezer28260
SelasphorusflammulaChiriquÌ ProvincePanama0_C Freezer28261
SelasphorusflammulaChiriquÌ ProvincePanama0_C Freezer28267
SelasphorusflammulaChiriquÌ ProvincePanama0_C Freezer28268
SelasphorusflammulaChiriquÌ ProvincePanama0_C Freezer28269
SelasphorusflammulaChiriquÌ ProvincePanama0_C Freezer28280
SelasphorusflammulaChiriquÌ ProvincePanama0_C Freezer28283
SelasphorusflammulaChiriquÌ ProvincePanama0_C Freezer28293
SelasphorusflammulaChiriquÌ ProvincePanama0_C Freezer28306
SelasphorusflammulaChiriquÌ ProvincePanama0_C Freezer28313
SelasphorusflammulaChiriquÌ ProvincePanamaLiquid Nitrogen26457
SelasphorusflammulaSan JosÈ ProvinceCosta RicaLiquid Nitrogen19847
SelasphorusflammulaSan JosÈ ProvinceCosta RicaLiquid Nitrogen19883
SelasphorusflammulaSan JosÈ ProvinceCosta Ricaunknown16222
SelasphorusflammulaSan JosÈ ProvinceCosta Rica9952

Which means :

View attachment 1617284

You certainly know this better than me, but my understanding is that simoni is found in prov. de Heredia (Volcán Barva) and prov. de Alajuela (Volcán Poás); if so, it was presumably not sampled.
I think that what can be seen within S. flammula in this tree is more likely to reflect individual variation, rather than anything taxonomically significant.
Yes, that's very interesting and you're correct. I had assumed (mistakenly) that they sampled the three subspecies but I believe that simoni was not sampled in this study then. So it appears that is the difference between flammula and torridus. Simoni is the one that I think has the most potential to be something different although whether or not it is beyond my expertise. I just know that it is the most distinct morphologically and and has the smallest breeding habitat.
 
Yes, that's very interesting and you're correct. I had assumed (mistakenly) that they sampled the three subspecies but I believe that simoni was not sampled in this study then. So it appears that is the difference between flammula and torridus. Simoni is the one that I think has the most potential to be something different although whether or not it is beyond my expertise. I just know that it is the most distinct morphologically and and has the smallest breeding habitat.
Well it's unlikely to be much more distant (based on the original phylogeny snippet posted, distance from flammula to other species) even if it is a clade. But whether or not it's a species would be your choice !
 

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