Proposal (1088) to South American Classification Committee

 

 

Treat Phaethornis b. major as a separate species from P. bourcieri

 

 

Background: Phaethornis bourcieri (Straight-billed Hermit) is widely distributed in Amazonia.  It had been treated as a polytypic until Hinkelmann (1989) first showed that the subspecies whitelyi (of the Guianan Shield, as one might predict from the eponym) was not diagnosable.  But Hinkelmann also studied the poorly known south bank population in eastern Brazil, and found it to be diagnosable; he described this population as a new subspecies, P. b. major, based on major size differences (hence the species epithet).  Although he could find only two specimens, their size difference was so great that he felt comfortable in describing it as a new taxon; their wing and tail lengths were roughly 5 mm longer than typical birds.  He could find no plumage differences between major and other populations. This classification was followed by Schuchmann in HBW, Dickinson and Remsen (2013), and others.

 

P. b. bourcieri (Lesson, 1832): north of the Amazon from se. Colombia, Ecuador, and ne. Peru east through the Guianan Shield region, and south of the Amazon in e. Peru, extreme w. Brazil, and Pando (Bolivia).

P. b. major Hinkelmann, 1989: south of the Amazon in Pará along the Rio Tapajós.

 

Note that the gap between in the range south of the Amazon is filled by Phaethornis philippii.

 

New information:

 

GENETICS

 

Araújo-Silva et al. (2017) sequenced 2600+ base pairs of mtDNA (ND2, cytb) nDNA (BF5) from 41 specimens of P. b. bourcieri and 13 from P. b. major (as well as other Phaethornis spp., including the third straight-billed Phaethornis, P. koepckeae).

 

Here are the results expressed as a tree:

 

 

Thus, major clusters with philippii and koepckeae with strong support, not with P. b. bourcieri.  A perhaps even more astounding result in that within P. bourcieri, Clade B (the Guianan Shield population) is as diverged from D and C as major is from philippii and koepckeae.  The oldest node in the tree is estimated at 3.1 to 4.4 MYA.

 

PLUMAGE and BARE PARTS

 

Araújo-Silva et al. (2017) cited Vitor Piacentini’s unpublished dissertation (2011) for additional information on phenotypic characters of major.  Perhaps Vitor will elaborate.  Hinkelmann had only two specimens of major when he described it, but Piacentini had access to additional (and new?) specimens.  From Araújo-Silva et al. (2017):

 

“Clade A birds (P. b. major) have much lighter grey bellies than those in clades B, C and D, in addition to bolder gular and malar stripes and reddish rather than yellowish mandibles (Piacentini 2011, L.E. Araujo-Silva and A. Aleixo pers. obs.).  Therefore, a heavily marked throat and red mandible are shared by P. b. major and P. philippii plus P. koepckeae, mirroring phylogenetic relationships recovered for these taxa.”

 

So, now the genetic results make more sense in the light of the new phenotypic information – very exciting! And the gray rather than tawny underparts shared by major and bourcieri is attributable to something besides a sister relationship.

 

Macaulay has only 7 photos of 3 individuals of major, but they are all useful.  Here’s one, along with photos of three other taxa in the analyses:

 

 

 


VOCALIZATIONS

 

Araújo-Silva et al. (2017) alluded to some vocal differences among bourcieri clades found by Piacentini (2011 dissertation), but we can let Vitor elaborate.  I listened to a few recordings of the taxa and populations in Macaulay and xeno-canto, and I quickly that no conclusions could be drawn from superficial dabbling, especially with the tiny amount of material available for major.

 

TAXONOMY

 

Araújo-Silva et al. (2017) proposed species rank for P. m. major based on their gene trees that were concordant with phenotypic characters found by Vitor and Hinkelmann.

 

They also proposed that the three clades within proper P. bourcieri should be recognized as species but discussed why it would be premature to name these taxa without more data and analyses.  A complicating factor is that the type specimen of bourcieri not only is lost but the type locality is “Brazil”, hence useless at this point.

 

Discussion and recommendation: I am tempted to recommend a YES on this one based on the rationale by the authors, especially because the west to east sequence south of the Amazon of koepckeae-philippii-major as a group has some intuitive biogeographical appeal.  On the other hand, I worry that the relationships shown by the mtDNA gene trees might not reflect true phylogeny, and without elaboration on the phenotypic characters, I feel uneasy.  If those of you willing to dive into the genetic analyses can assure me that the results are not just incomplete lineage sorting or investigate the actual data to see if a BF5 tree would be consistent with the mtDNA tree, then I will feel more certain

 

English names: I recommend a separate proposal on this if the split passes.  Tapajos Hermit would be an obvious candidate, but that name is taken by P. aethopygus. Hinkelmann’s Hermit has a nice ring to it, too.  Hinkelmann published a number of important papers on Phaethornis and was the one who “discovered” the taxon.

 

References:

ARAÚJO-SILVA, L. E., L. S. MIRANDA,L. CARNEIRO, AND  & A. ALEIXO.  2017.  Phylogeography and diversification of an Amazonian understorey hummingbird: paraphyly and evidence for widespread cryptic speciation in the Plio-Pleistocene.  Ibis 159: 778–791.

Hinkelmann, C.  1989.  Notes on the taxonomy and geographic variation of Phaethornis bourcieri (Aves: Trochilidae) with the description of a new subspecies. Bonn. zool. Beitr 40: 99-107.

 

 

Van Remsen, July 2026

 

 

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Vote tracking chart:

https://www.museum.lsu.edu/~Remsen/SACCPropChart1044+.htm

 

Comments from Areta: “YES. Split! The phylogenetic relationships, depth of divergence and phenotypic distinctions all point to the same direction, and recognizing Phaethornis major is the logical conclusion. The sorting of the remaining populations of P. bourcieri to either other species level or subspecies level taxa will have to await deeper studies. At present, the nomenclatural aspects need attention (especially, to which population would the name bourcieri strictly apply) and further sampling, coupled to vocal and formal morphological analyses are needed, especially in the light of lack of distinctiveness uncovered by Vitor, seemingly contradicting none other than the great John T. Zimmer.

 

“To answer Van’s point, the dataset is not purely mitochondrial. The supplementary material shows consistent nuclear (BF5) and mitochondrial (CytB and ND2) phylogenetic trees:

https://onlinelibrary.wiley.com/action/downloadSupplement?doi=10.1111/ibi.12500&file=ibi12500-sup-0001-Supinfo.docx. Also, the sister relationship between major and philippii-koepckeae was recovered by McGuire et al. (2014).”

 

Comments from Zimmer: “YES, to splitting, and treating major as a species distinct from the rest of P. bourcieri.  The phylogenetic data would certainly seem to point to this conclusion, both in terms of the depth of the divergence indicated in the tree branches, and, in terms of major clustering with the other South Bank taxa (philippii and koepckeae) rather than the other three clades of bourcieri.  A split is further supported on phenotypic grounds, in that major is demonstrably larger in measurements, and in plumage characters.  As regards phenotypic differences, I would note that the Brazilian website/photo archive WikiAves has 29 photos of major and many more of other bourcieri from other parts of Brazil (outside the range of major), and although the noted plumage distinctions seem to hold up, the distinctiveness of mandible color does not.  All of the photos of major that I examined appear to show a red base to the lower mandible, but photos of bourcieri from various N Bank locations (Manacaparu, Manaus, Amapá) included individuals with a yellow base to the lower mandible as well as individuals with a red base to the lower mandible, with both mandible colors being represented from the same localities.  Plumage differences, particularly the color of the underparts, appeared to be much more consistent.  I would agree that further splitting of bourcieri (apart from recognizing major as distinct), although suggested by the phylogenetic data, is premature without further analysis, especially given concerns over lack of corresponding phenotypic differentiation, as well as nomenclatural concerns regarding the missing holotype and the ambiguous nature of the described type locality.”