Proposal (764) to South American Classification Committee

Recognize Anthus brevirostris as a separate species from Anthus furcatus

Effect on SACC: This would split Anthus brevirostris fromA. furcatus.

Background & New information: The current classification considers the taxon brevirostris to be a subspecies of A. furcatus, following most recent classifications.

Analysis 

According to new multilocus (ND2, ACOI9, MB, FGB5) genetic and vocal data (Van Els & Norambuena 2017), the taxon brevirostris is sister to furcatus, but the divergence between them is deep. The split between both occurred approximately 1-1.5 Mya. Genetic divergence between brevirostris and furcatus is fairly high (~2.6%) and on par with divergence between other Neotropical pipit taxa recognized at present as full species. The voices of brevirostris and furcatus are similar syntactically, but consistently different in multiple ways; furcatus’ song length is shorter, but its buzz covers a broader frequency spectrum and notes before and after the buzz are more complex.

Finally, brevirostris is geographically isolated from furcatus elevationally, and it lives in a rather different environment than that species. Whereas brevirostris uses short grass, pastures, and rolling hills with a mix of bunch-grass and short grass in the puna zone to 4300 m (Tyler 2004), furcatus occurs mainly in temperate lowland grassland. Most sources indicate that the ranges of brevirostris and furcatus do not approach each other (Olrog 1963, Peters 1960, Tyler 2004), but they may overlap elevationally in Tucumán Province, Argentina, and this should be verified.

Conclusion

We recommend separating the two subspecies and we propose the name Puna Pipit for brevirostris, as it appears to be tightly linked to semi-arid high-elevation puna habitat throughout its range. We acknowledge that the scientific name brevirostris agrees closely with the English name Short-billed Pipit, but prefer to retain this name for the nominate. Given the facts stated above, A. brevirostris should precede A. furcatus in the linear sequence of Motacillidae.

References

Olrog, C.C. 1963. Lista y distribución de las aves argentinas, Vol. 9. Tucumán: Universidad Nacional de Tucumán, Instituto Miguel Lillo.

Peters, J.L. 1960. Checklist of the Birds of the World, Vol. 9. Cambridge: Harvard University Press.

Tyler, S. 2004. Family Motacillidae (Pipits and wagtails). In Del Hoyo, J., Elliott, A. & Christie, D.A. (eds.) Handbook of the Birds of the World: Cotingas to Pipits and Wagtails, Vol. 9: 686–786. Barcelona: Lynx Edicions.

Van Els, P. & H.V. Norambuena. 2018. A revision of species limits in Neotropical pipits Anthus based on multilocus genetic and vocal data. Ibis 160: 158-172.

Heraldo V. Norambuena & Paul van Els, July 2017

Note from Remsen: If this proposal passes, a separate proposal will be need for English names. SACC guidelines recommend using different names for daughter species than parent to prevent confusion,

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Comments from Stiles: "YES, supported by genetic, vocal and ecological differences in a genus like Anthus in which morphological differences between species are often subtle and easily overlooked."

Comments from Areta: "YES. The relatively deep (for a Neotropical pipit) genetic divergence and the diagnostic vocalizations support the split."

Comments from Zimmer: “YES. The genetic, vocal and ecological data are congruent, and they support splitting brevirostris from furcatus.”

Comments from Jaramillo: “YES. This difference has been on the radar for some time, it is great that they were able to attack the problem with multiple datasets.”

Comments from Claramunt: “NO. The evidence is weak and the sample size low. A 2.6% mitochondrial divergence may sound high, but it may not be high for a widespread and structured population. Only four genetic samples from three localities were analyzed, and only two (one of each subspecies) are shown in the tree (the ND2 sequence from Tucuman is not even in GenBank, so I could not check if it is identical to the Uruguayan haplotype or what). The samples of brevirostris come from Peru, thus, far from the potential contact zone. So, we don’t know if the divergence is divergence of species level-lineages or divergence of gene genealogies within the same species. The map showing the sampling is a mess; it does not show the sample from Uruguay or Puno but a sample from Chile, instead. The vocal samples also come from far away the contact zone (only one sample from Jujuy) and the songs are structurally similar. If the variation in songs is gradual and clinal, we would not know. Plumage differences are only assumed given the taxonomy but not crucially examined. The difference in habitat is used as a further piece of evidence but this is misleading; brevirostris and furcatus live in different habitats mainly because they live in different regions with different characteristics. It has to be shown whether they have actual differences in habitat preference. This is a borderline case for which some further evidence is required, in my opinion.”

Comments from Pacheco: “NO. After reading Santiago´s comments, I accept his arguments that for a safer decision, additional and better distributed sampling is needed to rule out the possibility of cline.”

Comments from Robbins: “YES. I’m on the fence on this one, as a result of comments by Santiago. However, given the relatively high genetic divergence (for Anthus) coupled with vocal and plumage differences, I will support this split for now. So, a YES for recognizing brevirostris as a species.”

Comments from Remsen: “NO. Santiago raises many valid concerns, sufficient for me to consider any taxonomic decision premature at this point. Follow-up sampling with these problems addressed should provide sufficient data on which to make a decision.”

Comments from Cadena: “NO for reasons described by Santiago.”