Proposal (833) to South American Classification Committee
Treat Lophornis verreauxii as a separate species from Lophornis chalybeus
The SACC´s footnote 27b is as follows:
“The subspecies verreauxii was formerly (e.g., Cory 1918) considered a separate species from Lophornis chalybeus, but Peters (1945) and Zimmer (1950c) treated them as conspecific. Del Hoyo & Collar (2014) treated verreauxii as a separate species (“Butterfly Coquette”) based on plumage differences; see also Donegan et al. (2015). Proposal needed.
Donegan et al. (2015) presented a summary of the case:
Del Hoyo & Collar (2014) proposed restricting L. chalybeus to the Atlantic forest of Brazil, which would make L. verreauxii the new name for more widespread western Amazonian populations of Colombia, Ecuador, Venezuela, Brazil and Guianan countries. Males of L. verreauxii have an elongated crest (3, most conservatively), which is absent in L. chalybeus. The two have different tail coloration in both sexes (2) and underparts coloration (2), which is most prominent in females.
...then mentions 24 sources after Peters-Zimmer that maintains Lophornis chalybeus as polytypic species. They also include as one of the reasons not to implement the split immediately:
Restall et al. (2006) illustrate klagesi of eastern Venezuela as having a different crest length from
verreauxii. Del Hoyo & Collar (2014) placed this subspecies with verreauxii but did not comment on the differentiation of klagesi. An inspection of sonograms suggests that L. chalybeus call notes may attain lower minimum frequencies ... and have a different pattern of overtones. However,
the available sample is small (n=2 for chalybeus and n=3 for verreauxii) and these differences need confirming with a greater vocal sample.
I add that before Del Hoyo & Collar, Rolf Grantsau (2010. Guia completo para identificação das aves do Brasil) – an author who was an expert on hummingbirds – implemented this split in his last work.
In some of the new call samples of the nominal form of L. chalybeus (n = 12, with sonograms http://www.wikiaves.com.br/midias.php?tm=s&t=s&s=10627), it is possible to notice that the pattern of overtones – highlighted by Donegan et al. (2015) as a possible distinction – is replicated.
The southernmost populations of L. c. verreauxii are separated by about 1,700 km from nominal taxon. L. c. klagesi are separated not less than 3,700 km from nominal taxon, but its distribution approaches L. verreauxii in southern Venezuela (Hilty, S. L. 2002. Birds of Venezuela, p. 407).
The original diagnosis of L. klagesi (comparing it with verreauxii. Berlepsch & Hartert 1902. Novitates Zoologicae 9, p.89) indicates the following:
The colour of the whole body is of a darker green; the rectrices and upper tail-coverts differ striking in their dark bronzy olive instead of dark coppery bronze-colour. The long ornamental feathers on the sides of the throat are of a darker green, and have smaller and less conspicuous white tips.
Nothing is mentioned about the smaller crest size. The characters of klagesi do not place this taxon between verreauxii and the nominal form. These minor plumage differences can be clinal. See illustrations below.
Due to the relevant differences (nothing subtle) in plumage, measurements and also those potentially observed on calls, I support this split between L. c. chalybeus and L. c. verreauxii (with klagesi).
Fernando Pacheco, May, 2019
Lophornis chalybeus chalybeus (from Grantsau 1988)
Lophornis chalybeus verreauxii (from Grantsau 1988)
Males of L. c. verreauxii (Left) and L. c. klagesi (from Restall et al. 2016)
Comments from Piacentini: “I’m totally for the elevation of L. [c.] verreauxi as a distinct species, but not because of the color differences on the plumage. Rather, they differ in structure! I have no idea how much familiar each SACC member is with the courtship display of nominate L. chalybeus, but the most important feature is that it raises the feathers on the crown to expose the blue skin!
This can be seen in several pictures, such as http://www.wikiaves.com.br/156305, and it may be as extreme as this: http://www.wikiaves.com.br/22901; although I suspect that the bird in this latter picture is lacking some feathers on the crown (something “intentional”?).
Anyway, please note that, in contrast to the nominate form, L. [c.] verreauxi has elongated crown feathers, forming a crest. How can the bird show the skin with such long feathers? I bet these feathers would completely conceal the skin on the crown, or at least change dramatically the visual effect, which I would safely assume as a totally distinct display. And if the two populations differ in their display, that would serve as a pre-zygotic barrier to free gene flow – at least I believe that the burden of proof would be with those who may claim that two birds that differ markedly in plumage color, structure and (assumed) behavior/display would freely mate if in contact.
By the way, I briefly mentioned that in our art book “Beija-flores do Brasil” (Piacentini & Ribenboim 2017). There is an English translation of my text in the end of the book (made by another person):
“During courtship, the male opens his [lateral] tufts forward, in a fan, lowers his bill to his chest and raises the feathers on his crown to display the blue naked skin on the vortex. The long feathers in [the crest of] the Amazonian form certainly preclude displaying the skin on the crown, which is conducive to concluding that there are differences between the nuptial displays of the two taxa, thus reinforcing the idea that they are distinct species.”
So, in some ways this hypothesis may even be considered published! With all that in mind, I strongly support a YES vote to this proposal.
Comments from Robbins: “YES, what really persuaded me was the additional comments by Vitor and those amazing photos of displaying chalybeus. Unless verreauxi is doing something equally unexpected with those elongated crown feathers, i.e., it has colored skin underneath and somehow exhibits it, I find Vitor’s supposition to be totally believable.”
Comments from Zimmer: “YES”. I don’t know verreauxii/klagesi particularly well, but I’ve got lots of field experience with chalybeus, and on the relatively few occasions that I’ve encountered the former, I’m always struck that it is a different beast from the Atlantic Forest birds with which I am so familiar. The elongate crest of verreauxii really does give it a very different look, and, as Fernando alludes to in the proposal, there are additional color pattern differences as well. I don’t know the voice of the Amazonian birds, but Vitor’s points regarding the display of chalybeus are spot-on, particularly with respect to likely display differences representing pre-zygotic barriers to gene flow. As Van and Vitor both opine, I think the burden of proof is on those who would maintain these rather different birds as conspecific, particularly given that they were lumped by Peters without any published rationale.”
Comments from Areta: “YES. The differences in plumage coloration and structure support the split. The situation with klagesi demands further study, but I am fine with provisionally retaining it within verreauxi.”
Comments from Bonaccorso: “YES. Although no molecular evidence is provided, differences in plumage and especially the crest in verreauxii, make me think that if they would get together, pre-zygotic reproductive isolation would be the outcome. With differences also in song and displays, I think we do have two good species.”
Comments from Ribas: “YES. The differences in plumage are strong, and I also see no reason, considering the described spatial distribution of the phenotypic diversity, to treat these taxa as the same species.”
Comments from Stotz: “YES. A number of plumage differences between these species, and some evidence of vocal differences, plus the comments of those members of the committee with greatest familiarity with the taxa in the field convince me to accept this change.”