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 (2017) cited Vitor Piacentini’s unpublished dissertation (2011) for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 seems like an obvious candidate.
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