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 Serran’a Pil—n 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 Serran’a Pil—n 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 Serran’a Pil—n. This led to the collecting of two specimens in the Yungas of La Paz, sound-recordings at the type locality, on Serran’a 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 distribuci—n y color podr’a ser perfectamente una subespecie de fasciatus, las notables diferencias en el canto (segœn se–alan los autores) lo se–alan 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-ˆ-vis P. griseiceps) the available evidence definitely favors separating P. weedeni from fasciatus at the species level."

 

Comments from Pacheco: "YES. Pelo apresentado Ž plenamente conceb’vel acatar a nova espŽcie."

 

Comments from Zimmer: ÒYES.  Published evidence for recognition as separate from P. fasciatus is compelling.Ó