Proposal (#364) to South American Classification
Committee
Recognize Phyllomyias
weedeni (Yungas Tyrannulet)
Effect on South
American CL: This proposal would add a newly described
species to the list.
Background:
This cryptic species has been overlooked or included under P. fasciatus
in recent standard references on (Neotropical) birds (e.g. Ridgely & Tudor
1994, Fitzpatrick et al. 2004); see Herzog et al. (2008) for details.
New information:
Parker et al. (1991) observed and sound-recorded several Phyllomyias
tyrannulets on Serranía Pilón in extreme western Beni department and
tentatively identified them as Phyllomyias fasciatus (Planalto
Tyrannulet), but noted that their vocalizations were faster and higher-pitched
than those of P. fasciatus and concluded that the Serranía Pilón
population may represent an undescribed form. This population received no
further study until 1997, when Herzog et al. (2008) sound-recorded the
vocalizations of three unfamiliar Phyllomyias tyrannulets in the Yungas
of La Paz department, which were later identified by B. M. Whitney as identical
to those recorded by T. A. Parker on Serranía Pilón. This led to the collecting
of two specimens in the Yungas of La Paz, sound-recordings at the type
locality, on Serranía Pilon, and at several other localities, subsequent
analysis of those recordings and recordings of widely allopatric P. fasciatus
from Brazil and Argentina, and a review of specimens in three US collections.
Herzog et al. (2008) found that both the song and the antiphonal duet of new
species differ conspicuously and highly significantly from those of all three
subspecies of P. fasciatus. It further differs in plumage from
all three subspecies of P. fasciatus (and especially from P.
f. brevirostris) by the strongly contrasting gray crown and olive
back, and from P. f. fasciatus and P. f. cearae
by more intensively yellow underparts. It is notably smaller than P. f.
brevirostris and P. f. cearae (primarily in wing
chord and tail length) and similar in size to the nominate subspecies, although
small sample size did not allow for statistical analysis of measurements.
Presumably weedeni and fasciatus are sister taxa. The new species
has a restricted range and occurs in the lower Yungas and upper foothills of
extreme southeastern Peru (Puno department) and N Bolivia (La Paz, Beni and
western Cochabamba departments).
Literature Cited:
FITZPATRICK, J. W.
2004. Family Tyrannidae (tyrant-flycatchers). Pp. 170-462 in "Handbook of
the Birds of the World, Vol. 9. Cotingas to pipits and wagtails." (J. del
Hoyo et al., eds.). Lynx Edicions, Barcelona.
HERZOG, S. K., M. KESSLER, AND J. A. BALDERRAMA. 2008. A new species of
tyrannulet (Tyrannidae: Phyllomyias) from Andean foothills in northwest
Bolivia and adjacent Peru. Auk 125: 265-276.
PARKER, T. A. III, M. GELL-MANN, A. CASTILLO U., AND O. ROCHA. 1991. Records of
new and unusual birds from northern Bolivia. Bull. Brit. Ornith. Club 111:
120-138.
RIDGELY, R. S., AND G. TUDOR. 1994. The birds of South America, vol. 2. Univ.
Texas Press, Austin.
Sebastian
Herzog, July 2008
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Comments from
Schulenberg: "Yes. The description makes a convincing
case that weedeni is a species distinct from Phyllomyias fasciatus.
"That said, I
wonder if further research will show that weedeni is closer to Phyllomyias
griseiceps than it is to fasciatus (with a tip of the hat to Dan
Lane, who first pointed out to me the resemblance). In several of the ways in
which weedeni differs from fasciatus, it does so in ways that
heighten its resemblance to griseiceps, e.g., smaller size and duller
wingbars. On the other hand, vocally weedeni does seem to be closer to fasciatus
than it does to griseiceps.
"Also, griseiceps
is an Andean species. Of course there are biogeographic connections between the
Yungas of Bolivia and eastern Brazil (Phibalura, most famously), but the
overwhelming pattern is for species in the Bolivian Andes to be most closely
related to taxa further north in the Andes.
Griseiceps has been collected as far south as the Ene valley in
Junin, Peru, within 650 km of the Peruvian records of weedeni (and so
closer than the gap between weedeni, and nearest known locality for fasciatus
in eastern Bolivia).
"The description
of weedeni makes very little mention of griseiceps, other than to
say that weedeni differs by the presence of wingbars. But all
indications are that the wingbars of weedeni are indistinct as well
(examine the color plate on the cover of the April 2008 Auk). So in the hand,
at least, griseiceps and weedeni must be pretty similar (although
I haven't weedeni in the hand, myself!).
"I don't know griseiceps
well, especially vocally. There is a vocal difference, however, between weedeni
and at least pallidiceps, the southernmost subspecies of griseiceps.
In the duet of pallidiceps, the song is rhythmic (see the Dan Lane
description, in Schulenberg et al. 2007; also check http://www.xeno-canto.org/browse.php?query=Phyllomyias+griseiceps.).
This is different in pattern from the corresponding vocalization of weedeni,
which is a slightly decreasing series of similar notes (besides the comments in
the description of weedeni, see http://www.xeno-canto.org/browse.php?query=Phyllomyias+sp.+nov.)."
Comments from Stotz:
"YES. Seems like a fairly straightforward new species. Tom's
comments on possible relationship with griseiceps are interesting and
might strengthen the case for splitting weedeni. I would note
though that the subspecies of fasciatus also vary in the strength of
their wingbars, with brevirostris showing pretty weak wingbars and fasciatus
and cearae stronger ones. I have to say that the description and
data on the various subspecies of fasciatus makes me think that cearae
almost certainly is a different species, and I have always wondered about brevirostris.
That shouldn't stop us from recognizing weedeni."
Comments from Nores:
"YES. Es evidente que se
trata de algo diferente de fasciatus. Aunque por distribución y color
podría ser perfectamente una subespecie de fasciatus, las notables
diferencias en el canto (según señalan los autores) lo señalan como una
diferente especie."
Comments from
Jaramillo: "YES - This seems clear cut. The
comments by Tom are interesting but I don't see that it weakens the argument to
recognize weedeni. In particular the description of different sounding
voices is of importance here."
Comments from
Jaramillo: "YES. Though there are complications
(vis-à-vis P. griseiceps) the available evidence definitely favors
separating P. weedeni from fasciatus at the species level."
Comments from Pacheco:
"YES. Pelo apresentado
é plenamente concebível acatar a nova espécie."
Comments from Zimmer:
“YES.
Published evidence for recognition as separate from P. fasciatus is compelling.”