Proposal (842) to South American Classification Committee
A. Split Rhynchospiza strigiceps in two species, and B. Establish English names
Effect on SACC list: if passed, this proposal would add another Rhynchospiza species to the SACC list and would provide two new common English names for species resulting from the split.
Current SACC note reads:
"Rhynchospiza was traditionally (e.g., Hellmayr 1938, Meyer de Schauensee 1970) treated as a monotypic genus, with its sole species being stolzmanni; however, most recent authors (e.g., Ridgely & Tudor 1989) have followed Paynter (1967, 1970a) in merging this into Aimophila, which was widely suspected of being polyphyletic (Ridgway 1901, Storer 1955b, Wolf 1977). DaCosta et al. (2009) have confirmed that Aimophila is polyphyletic and that the South American taxa are not members of true Aimophila; they recommended resurrection of Rhynchospiza, which would also include stolzmanni’s sister species, A. strigiceps. SACC passed to resurrect Rhynchospiza. Klicka et al. (2014) found that Rhynchospiza is sister to the group of sparrow genera that includes true Ammodramus, Arremonops, and Peucaea."
More recently, Areta et al. (2019) proposed to split R. strigiceps into two species based on morphological, genetic, biogeographical and vocal evidence, and coined new common English names:
Part A - Recognize Rhynchospiza dabbenei as a distinct species from R. strigiceps
The abstract and figures in Areta et al. (2019) provide a clear synthesis of the reasons for the split:
“The genus Rhynchospiza comprises two species, the monotypic Tumbes Sparrow (R. stolzmanni) and the Stripe-crowned Sparrow (R. strigiceps) with subspecies strigiceps and dabbenei. In the study reported here we evaluated the taxonomic status of these taxa and discussed key features involved in speciation. All three taxa exhibited multiple differences in plumage, morphology, and vocalizations, supporting the recognition of three species in Rhynchospiza. The very large-billed R. stolzmanni has a song composed of a succession of faster complex trilled phrases, shows a small black loral line and dark chestnut head stripes with large dark central-stripe to individual feathers, and is resident in the Tumbes region. The large and heavy dabbenei has a song consisting of a series of simple chirping notes, shows a large black loral crescent and chestnut head stripes with a reduced to absent dark center to feathers, and inhabits the Austral Yungas as a year-round resident. The small and pale strigiceps has a song consisting of a succession of complex trilled phrases, shows a small black loral line and rufous-brown head stripes with large dark central-stripe to feathers, and inhabits Dry and Sierran Chaco where it is a partial migrant. Locality data and ecological niche modeling show that dabbenei and strigiceps are allo-parapatric and use different altitudinally segregated habitats at their zone of parapatry. Molecular phylogenetic analyses (NADH dehydrogenase 2 [ND2] gene) revealed R. stolzmanni to be sister (11.5% divergent) to a recently diverged dabbenei and strigiceps clade (1.6% divergent). We conclude that the genus Rhynchospiza comprises three species-level entities, each restricted to a major biogeographic region, and that vocalizations and facial patterns provide key evidence on species limits in these otherwise similarly plumaged taxa. The evolutionary–cultural differences in songs, with complex phrases in those of R. strigiceps and R. stolzmanni , and single notes in the songs of R. dabbenei, suggest changes in the innate vocal learning template during speciation in the latter.”
Recommendation: we recommend a YES vote to Part A.
Figure 1. Rhynchospiza taxa
Figure 2. Geographic distribution and models of Rhynchospiza taxa
Figure 3. Morphological characterization of Rhynchospiza taxa
Figure 4. Songs of Rhynchospiza taxa (two individuals per taxon)
Figure 5. Calls of Rhynchospiza taxa
Figure 6. Phylogenetic relationships of Rhynchospiza taxa
Part B - Adopt common English names for R. strigiceps and R. dabbenei
Areta et al. (2019) wrote:
“We have not detected any nomenclatural problem with names in current usage. Our examination of the type specimens of all Rhynchospiza taxa and the examination of the illustration in the description of R. stolzmanni (type lost; Mlíkovský 2009 ) is in agreement with previous views (Sharpe 1888 ; Hellmayr 1938 ). Now that the strictly South American Rhynchospiza can be recognized as three different species-level entities, we would like to propose new common English names for the two southern representatives. The current common name for the entity composed by R. strigiceps and R. dabbenei is Stripe-capped Sparrow, which is confusingly similar to Stripe-headed Sparrow (Peucaea ruficauda ), a name that has also been applied to R. strigiceps (Hellmayr 1938 ). The uninformative Dabbene’s Stripe-headed Sparrow has been proposed for R. dabbenei (Hellmayr 1938). The type species of Rhynchospiza is stolzmanni, the Tumbes Sparrow, although Taczanowski’s Stripe-headed Sparrow has been used (Hellmayr 1938). The minor plumage distinctions between Rhynchospiza species contrast markedly with their clear separation in different biogeographic realms. We suggest that new comparative common names emphasizing the biogeographic regions to which each of the three Rhynchospiza is restricted shall facilitate communication. We thus propose the following taxonomy, common English names, and linear sequence:
Tumbes Sparrow Rhynchospiza stolzmanni (Taczanowski 1877)
Yungas Sparrow Rhynchospiza dabbenei (Hellmayr 1912)
Chaco Sparrow Rhynchospiza strigiceps (Gould 1839).”
B1- Adopt Yungas Sparrow for R. dabbenei
B2- Adopt Chaco Sparrow for R. strigiceps
B3- Adopt Dabbene´s Stripe-capped Sparrow for R. dabbenei
B4- Keep Stripe-capped Sparrow for R. strigiceps
Recommendation: we recommend a YES vote to Parts B1 and B2.
J. I. Areta, E. A. Depino & I. Holzmann
Comments from Stiles: “YES to splitting dabbenei and thus recognizing three species in this group, based upon clear differences in size, vocalizations and their near parapatry at different elevations and migratory vs. sedentary habits; the small difference in cytB simply indicates recency of the split (perhaps with incomplete lineage sorting), but the differences mentioned seem concordant with considering them to be good biological species. I also agree to the English names proposed (B1B2), which highlight the differences in ecology and distributions.
Comments from Remsen: “A. YES. The evidence is overwhelming, in my opinion, that these two should be treated as separate species. YES on B1+B2 – these are excellent choices. A moot point, but B4 is “illegal” under near-universal conventions of formation of common names. B4 would have to be “Something” Stripe-capped Sparrow if we were to go with compound names, and the logical choices for B3-B4 would be taken from B1+B2, i.e. Yungas Stripe-capped Sparrow and Chaco Stripe-capped Sparrow. Therefore, let’s consider NO votes to be something other than B1+B2, but not necessarily the current B3+B4.”
Comments from Bonaccorso: “A. YES. I agree that the evidence is overwhelming, especially the song and parapatry data!”
Comments from Pacheco: “YES. Recognition in three species-level entities is compatible with the data presented and therefore represents the best treatment.”
Comments from Claramunt: “YES. The only piece of evidence missing is an analysis of geographic variation to make sure that variation is not clinal and that there is not a region of intergradation between dabbenei and strigiceps, for example, in Tucuman. But accepting that morphological and song differences are diagnostic and congruent, there is strong evidence for the species status of dabbenei.”
Comments from Jaramillo: “A. YES. Very nicely done. The habitat differences are quite remarkable really, and perhaps what is driving the speciation.
B1 – YES to Yungas Sparrow
B2 – Yes to Chaco Sparrow
B3 – NO
B4 – NO”