Proposal (882) to South American Classification Committee

Split Synallaxis stictothorax into two species: coastal S. stictothorax and interior S. chinchipensis

Effect on SACC classification: add Synallaxis chinchipensis as a species separate from S. stictothorax.

Background: From SACC notes:

“Ridgely & Tudor (1994) and Ridgely & Greenfield (2001) considered the upper Marañon population chinchipensis as a separate species, but no analysis or data published. SACC proposal to elevate chinchipensis to species rank did not pass because of insufficient published data.”

Well, that analysis has finally been published in the form of Stopiglia et al. (2020), using morphology, and the phylogenetic reconstruction from Tobias et al. (2014), in which was demonstrated that S. chinchipensis is not sister to S. stictothorax, but rather to S. hypochondriaca. This, in addition to the distinct voices of S. stictothorax and S. chinchipensis (e.g., as described in Schulenberg et al. 2010, and easily heard in the recordings linked below) require the recognition of the latter as a full species, as suggested by Ridgely and Tudor (1994) and Ridgely and Greenfield (2001).

Voice comparison:

Synallaxis stictothorax:
https://www.xeno-canto.org/species/Synallaxis-stictothorax

Synallaxis chinchipensis:
https://www.xeno-canto.org/species/Synallaxis-stictothorax?query=ssp:%22chinchipensis%22

Analysis: This split has been anticipated for a long time, and it is one that is not a surprise given the morphological and vocal distinctions between S. chinchipensis and the remainder of S. stictothorax. Basically all that was missing was a publication that laid out these characters. The phylogeny that shows that the two are not sisters should make the change in classification clear.

Recommendation:
I recommend that SACC accept the elevation of Synallaxis chinchipensis to full species separate from S. stictothorax.

Literature cited:

Ridgely, R. S., and P. J. Greenfield. 2001. The birds of Ecuador. Status, Distribution, and Taxonomy, vol. I. Ithaca, New York, Cornell University Press.

Ridgely, R. S., and G. Tudor. 1994. The Birds of South America, vol. 2. Austin, University of Texas Press.

Schulenberg. T. S., D. F. Stotz., D. F. Lane., J. P. O’Neill, and T. A. Parker, III. 2010. Birds of Peru, revised and updated edition. Princeton, New Jersey, Princeton University Press.

Stopiglia, R., F. A. Bockmann, C. P. de Assis, and M. A. Raposo. 2020 Alpha taxonomy of Synallaxis stictothorax group (Aves: Passeriformes: Furnariidae): Synallaxis chinchipensis Chapman, 1925 as a valid species, with a lectotype designation. Vertebrate Zoology 70: 319-331.

Tobias, J. A., C. K. Cornwallis, E. P. Derryberry, S. Claramunt, R. T. Brumfield, and N. Seddon. 2014. Species coexistence and the dynamics of phenotypic evolution in adaptive radiation. Nature, 506: 359– 363.

Dan Lane, Aug 2020

Comments from Stiles: “YES; all lines of evidence coincide in supporting this split.”

Comments from Areta: “YES, chinchipensis differs in vocalizations, genetics, and plumage to the point that it deserves treatment at the species level.”

Comments from Claramunt: “YES. Plumage, morphological, and vocal differences alone support chinchipensis as a different species. On top of that, it is not even sister to stictothorax.”

Comments from Robbins: “YES for recognizing chinchipensis, as this is a straightforward proposal that does not leave any doubt of the course of action.”

Comments from Zimmer: “YES. I was a “reluctant NO” vote the first time around on this issue, noting that, in addition to the obvious plumage and biometric distinctions between stictothorax and chinchipensis, that my own field experience and tape recordings did support the idea that the two taxa differed vocally, and that treating them as distinct species from one another would fit an established biogeographic pattern regarding Marañon versus coastal populations across several different taxa. The reason for my previous “no” vote, was the lack of any formal, published analysis. Such a publication is now available (Stopiglia et al. 2020), and it leaves no doubt as to the best course of action going forward.”

Comments from Jaramillo: “YES – Now that information that was widely known but unpublished has been published, we can separate these species.”

Comments from Pacheco: “YES. Confirming a 26-year presumption with robust evidence.”

Comments from Bonaccorso: “YES. Non-monophyly is key to separate them. Additional differences in measurements, song, and minor plumage differences provide diagnostic characters.”