Recognize Phaethornis aethopyga as a valid species

Proposal (442) to South American Classification Committee

Effect on SACC list: This would add a “new” species to SACC list.

Background: This is a quite simple case and there is not much to say here that is not said in the Abstract of Piacentini et al. (2009). Zimmer (1950) described aethopyga as a new subspecies of the (then) broadly defined Phaethornis longuemareus group. Nobody ever studied its taxonomic status until the 1990’s, when Hinkelmann (1996) misinterpreted the plumage pattern of the 3 specimens available to him and proposed that aethopyga was a hybrid between P. rupurumii amazonicus and P. ruber. Given that it was treated either as a subspecies or a hybrid, it did not appear in SACC’s main list or in the Hybrid and Dubious Taxa list.

New data: The current SACC Note reads as follows:

9bb. Hinkelmann (1996) proposed that the subspecies P. l. aethopyga represented hybrids between P. ruber and P. rupurumii amazonicus. Piacentini et al. (2009) showed that aethopyga was not only a valid taxon but also probably worthy of species rank.

Piacentini et al. (2009) have reanalyzed the case based on 18 specimens of P. “longuemareus” aethopyga [the three examined by Hinkelmann plus 15 recently collected by us or colleagues], plus ca. 250 specimens related to the “longuemareus group” (sensu Zimmer 1950), and 66 and 211 specimens of the two alleged parental species P. rupurumii amazonicus and P. ruber, respectively. [Here comes a copy of the second half of the Abstract]: Despite showing some differences related to age and sex, all specimens agree in the general plumage pattern and are fully diagnosable when compared with any other taxon of the genus. The hypothesis of a hybrid origin becomes unsustainable when one notes that (1) P. l. aethopyga has characters that are unique and absent in the purported parental species, such as the white outer margins at the base of the rectrices; and (2) P. l. aethopyga occurs far from the distribution of one of the alleged parental species. Furthermore, field data show that P. l. aethopyga has attributes typical of a valid and independent taxon, such as lekking behavior. Therefore, given its overall diagnosis, P. aethopyga could at least be treated as a phylogenetic species. Yet its morphological and vocal distinctiveness with respect to other Phaethornis spp. in the “Pygmornis group” is greater than that observed between some species pairs traditionally regarded as separate biological species within the group, which supports its recognition as a species under the biological species concept.

I may add that, after publication, I have studied many more specimens (including five additional P. aethopyga) and listened to new recordings that not only confirmed our findings, but made me sure that P. aethopyga is among one of the most distinct species of the genus.

English name: P. aethopyga was already called Tapajós Hermit by birdwatchers even before our (or any) analyses became available, and indeed we suggested to keep that name since it highlights the center of endemism to which P. aethopyga seems restricted.

Recommendation: Of course I recommend a YES vote to recognize it as a valid species.

Literature cited:

Hinkelmann, C. 1996. Evidence for natural hybridization in hermit hummingbirds (Phaethornis spp.). Bulletin of the British Ornithologists’ Club 116:5–14.

Piacentini, V. Q., A. Aleixo, and L. F. Silveira. 2009. Hybrid, subspecies or species? The validity and taxonomic status of Phaethornis longuemareus aethopyga Zimmer, 1950 (Trochilidae). Auk 126: 604-612.

Zimmer, J. T. 1950. Studies of Peruvian Birds, no. 55. The hummingbird genera Doryfera, Glaucis, Threnetes, and Phaethornis. American Museum Novitates 1449:1–51.

Vítor de Q. Piacentini, May 2010

Comments from Stotz: “YES This seems like a well-documented split with a number of lines of evidence. Piacentini’s paper clearly demonstrates that Hinkelmann’s treatment of this taxon as a hybrid between P. ruber and P. rupurumii is not tenable (numerous specimens from hundreds of km away from range of rupurumii, characters not intermediate, or shared with either alleged parent.) I think the argument for not treating it as a subspecies of atrimentalis is sound, especially given the recent spate of splitting in the small Phaethornis. Morphologically, this is quite distinct from the other small Phaethornis (given that they all look the same).”

Comments from Zimmer: “YES. As Piacentini has clearly demonstrated, Hinkelmann’s treatment of aethopyga as a hybrid is incorrect. I’ve seen this taxon in the field, and examined a number of specimens in the hand, and find the morphological characters to be exactly as described by Piacentini, and to be of a magnitude comparable to the distinctions between other taxa in Phaethornis already recognized as good species. I have not encountered aethopyga on leks, but I do know of colleagues who have, and they are seemingly distinct vocally from other small Phaethornis.”

Comments from Stiles: “YES – the wealth of new specimens, distribution and ecology clearly trump the hybrid hypothesis and indicate that aethopyga is a good species.”

Comments from Pacheco: “YES. A frase de Vitor “P. aethopyga is among one of the most distinct species of the genus” encontra respaldo nos dados reunidos pelo autor da proposta. O tratamento de aethopyga como híbrido ou como forma de P. longuemareus foi plenamente imunizado.”

Comments from Nores: “YES. Aunque no he tenido oportunidad de observar ejemplares ni en el campo ni en museos, resulta evidente del trabajo de Piacentini et al. de que se trata de una buena especie.”