Proposal (590) to South American Classification Committee

Treat Epinecrophylla fjeldsaai as a subspecies of E. haematonota

Effect on SACC: If adopted, as recommended by Whitney and colleagues (2013), Epinecrophylla fjeldsaai Krabbe et al. 1999 would be removed (relegated to a subspecies of E. haematonota).

Background: In 1994 Niels Krabbe recorded and collected a pair of “stipple-throated” antwrens near Río Tiputini, Napo, Ecuador, with yellowish-brown backs. These specimens and eight additional yellowish-brown backed specimens later found in museum collections were compared to reddish-brown backed forms of E. haematonota from the area to the southeast. No intermediates were discovered in collections. Mapping locations found no geographic overlap of the two forms, and parapatry without any evidence of integration, was found along the Rio Tigre (fjeldsaai on the right bank, haematonota on the left). Vocal analysis was not undertaken because the available sample for fjeldsaai was inadequate. Based on parapatry and plumage integrity in an area with extensive floodplain dynamics, Epinecrophylla (then Myrmotherula) fjeldsaai was described as a new species (Krabbe et al. 1999).

Newly Published information. In the process of describing a new species in the Epinecrophylla haematonota complex, Whitney, Isler, Bravo, Aristizábal, Schunck, Silveira, and Piacentini undertook maximum-likelihood and Bayesian analyses of mtDNA from tissue throughout the range of the “stipple-throated” complex (E. spodionota, E. fjeldsaai, and E. haematonota). With reference to fjeldsaai, they found that the two available specimens were embedded within nominate haematonota with sequence divergence between fjeldsaai and the closer haematonota specimens of 0.5-1.2 percent although the locations of the haematonota samples were not very near the range of fjeldsaai. Unpublished genetic divergences in a nuclear intron showed that they were genetically indistinguishable (Bravo et al. in prep.). Based on a high similarity of mitochondrial and nuclear haplotypes, they concluded fjeldsaai is most appropriately ranked as a subspecies of E haematonota.

Recommendation: I recommend a "YES" vote on removing this antwren as a species to the list until more information, especially tissue samples and vocal recordings from both taxa in proximity can be obtained. Based on the evidence available in 1999, the conclusion was that fjeldsaai “most probably” should be ranked as a species. While molecular analysis is not definitive in defining species under the BSC, the weight of the molecular results pushes the balance of the scale to the subspecies side.

Literature cited

Krabbe, N., M. L. Isler, P. R. Isler, B. M. Whitney, J. Alvarez A., and P. J. Greenfield. 1999. A new species in the Myrmotherula haematonota superspecies (Aves; Thamnophilidae) from the western Amazonian lowlands of Ecuador and Peru. Wilson Bulletin 111: 157-165.

Whitney, B. M., M. L. Isler, G. A. Bravo, N. Aristizábal, F. Schunck, L. F. Silveira, and V. de Q. Piacentini. 2013. A new species of Epinecrophylla antwren from the Aripuanã-Machado interfluvium in central Amazonian Brazil with revision of the “stipple-throated antwren” complex. In: del Hoyo, J., Elliot, A., Sargatal, J., & Christie, D.A. (Eds), Handbook of the Birds of the World. Special Volume: New Species and Global Index. Lynx Edicions, Barcelona, Spain, pp. 263–267.

Morton Isler, October 2013

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Comments from Stiles: “YES. I agree that current genetic data do not support recognition of fjeldsaai as a distinct species, though this could change when more specimens and recordings become available.”

Comments from Pacheco: “NO. Adopting the precautionary principle, I will await the publication of Gustavo Bravo to accept this proposal.”

Additional information from Mort Isler, 10 Dec. 13: “I assembled eight loudsong recordings of E. fjeldsaai and  measured and compared them to 22 loudsong recordings of E. haematonota.  There were no diagnosable differences between the taxa.”

Comments from Robbins: “Given the new genetic data, for now, I vote YES for treating Epinecrophylla fjeldsaai as a subspecies of E. haematonota.”

Comments from Pérez-Emán: “NO. For the same reasons I voted YES in previous proposal and would keep E. fjeldsaai as a valid species until a more formal study of differences among a complete set of characters is published. This taxon is diagnosable by plumage and no intermediate individuals have been found in parapatric populations of fjeldsaai and haematonota. Molecular differences (low in mtDNA) or lack of it (nuclear gene) is evidence of a weakly differentiated taxon (as dentei) but not necessarily discard the possibility of considering this taxon as a valid species. It would have been useful to see the genetic structure (or lack of it) within the haematonota/fjeldsaai clade in Whitney et al. (2013). Additional vocal comparisons provided by Mort Isler might be critical for this comparison but I would prefer to examine such data in a more formal context as we have done it in the past.”

Comments from Remsen: “YES. Currently available data places burden-of-proof on treating fjeldsaai as a species.”

Comments from Cadena: “NO. Regarding the lack of genetic differences between fjeldsaai and haematonota (i.e. lack of differences in the genes studied), this does not really mean much by itself; these two may well be distinct species that diverged relatively recently. As far as I can tell, the two taxa are diagnosably distinct in plumage, and there are no intermediates despite their being in close geographic proximity. Thus, based on published evidence, I see no reason to change our classification. Mort Isler mentioned his unpublished vocal analyses; I predict that once these are out they will most likely make me change my mind. However, it would be necessary to see them published and be able to assess geographic sampling, etc.”

Comments from Jaramillo: “NO. Small genetic distances are expected if the species level taxon is young. So to change the treatment to a subspecies, I would prefer publication of the vocal data and comparison to other related taxa.”