Species limits and biogeography of Rhynchospiza sparrows

EMILIANO AGUSTÍN DEPINO; KEVIN EPPERLY; SERGIO A. SALVADOR; INGRID HOLZMANN; JUAN IGNACIO ARETA; STEVEN W CARDIFF

JOURNAL FUR ORNITHOLOGIE

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2019

0021-8375

The genus Rhynchospiza comprises two species, the monotypic Tumbes Sparrow (R. stolzmanni) and the Stripe-crowned Sparrow (R. strigiceps) with subspecies strigiceps and dabbenei. We evaluate their taxonomic status and discuss 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, dark chestnut head stripes with large dark cen- tral-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, has a large black loral crescent, chestnut head stripes with reduced to absent dark center to feath- ers, and inhabits the Austral Yungas as a year-round resident. The small and pale strigi- ceps has a song consisting of a succession of complex trilled phrases, shows a small black loral line, 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 eco- logical niche modelling show that. dabbenei and strigiceps are allo-parapatric and use different altitudinally segregated habitats at their zone of parapatry. Molecular-phylo- genetic analyses (ND2 gene) found R. stolzmanni as sister (11.5% divergent) to a re- cently diverged dabbenei and strigiceps clade (1.6% divergent). We conclude that the genus Rhynchospiza is comprised of three species-level entities, each restricted to a major biogeographic region, and that vocalizations and facial patterns provide key evi- dence on species-limits in these otherwise similarly plumaged taxa. The evolutionary- cultural differences in songs, complex phrases in R. strigiceps and R. stolzmanni and single notes in R. dabbenei, suggest changes in the innate vocal learning template dur- ing speciation in the latter.