Proposal (700) to South American Classification Committee
Elevate Henicorhina leucophrys anachoreta to species rank
Background: Recent studies based on genetic, morphological, and behavioral data suggest that the two wren taxa in the genus Henicorhina (Troglodytidae) that replace each other along elevational gradients in the Sierra Nevada de Santa Marta, northern Colombia, are reproductively isolated populations (Caro et al. 2013, see also Burbidge et al. 2015). However, the evidence has not yet resulted in taxonomic changes recognizing their status as distinct species.
New information: In a recently published note (Cadena et al. 2015), we summarized existing data and proposed to recognize the population inhabiting higher elevations as a different species (H. anachoreta) from the population occurring at lower elevations (H. leucophrys bangsi).The note is open access and available here:
Recommendation: Based on the analyses in Caro et al. (2013) and the data summarized by Cadena et al. (2016), I recommend voting YES to treating H. anachoreta as a species distinct from H. leucophrys.
Burbridge, T., T. Parson, P. C. Caycedo-Rosales, C. D. Cadena & H. Slabbekoorn. 2015. Playbacks revisited: Asymmetry in behavioural response across an acoustic boundary between two parapatric bird species. Behaviour 152: 1933-1951.
Cadena, C. D., L. M. Caro, P. C. Caycedo, A. M. Cuervo, R. C. K. Bowie & H. Slabbekoorn. 2015. Henicorhina anachoreta (Troglodytidae), another endemic bird species for the Sierra Nevada de Santa Marta, Colombia. Ornitología Colombiana 15.
Caro, L. M., P. C. Caycedo-Rosales, R. C. K. Bowie, H. Slabbekoorn & C. D. Cadena. 2013. Ecological speciation along an elevational gradient in a tropical passerine bird? Journal of Evolutionary Biology 26: 357-374.
C. Daniel Cadena, February 2016
Comments from Remsen: “YES. Parapatry without gene flow is as good as it gets for species rank.”
Comments from Stiles: “YES. The strong evidence for parapatry without interbreeding justifies species rank for anachoreta.”
Comments from Areta: “YES. Results of playback experiments and vocal differentiation, lack of gene flow in parapatry, morphological distinctions, phylogenetic data, and analysis of type material all support recognition of anachoreta as a separate species. The reasons behind the paraphyly of Henicorhina leucophrys are quite interesting. I do not fear recognizing non-monophyletic species, and I agree in that both faulty taxonomy and the speciation process in this group underlie the observed phylogenetic patterns.”
Comments from Pacheco: “YES. The convincing evidence of parapatry without reporting of crossbreeding justifies the proposal.”
Comments from Claramunt: “YES. The concurrent break in morphology and multiple independent genetic markers strongly suggests that these two parapatric populations are two separate lineages. Intrinsic reproductive isolation is also inferred by the lack of intergrades or hybrids in the contact zone. Vocal data are more ambiguous; vocal variation looks like an altitudinal cline, and playback experiments revealed that birds do respond to alien songs. But little is known about the significance of these responses. Males may be responding to alien songs because they may be defending territories from any Henicorhina around to defend resources, regardless of species identity. This, in turn, may promote vocal convergence rather than divergence, as in the case of Hypocnemis peruviana and H. subflava, described by Tobias & Seddon (2009, Evolution 63: 3168-3189). But whatever happens with the acoustic behavior here does not affect the fact that all other evidence indicate that there are two lineages that are differentiated genetically and phenotypically and are reproductively isolated. Finally, that H. leucophrys become paraphyletic after separation of H. anachoreta is problematic in principle, because they cannot be considered two separate lineages if they are not reciprocally monophyletic. However, I concur with Daniel in that this change is among the first steps towards a revision of the leucophrys complex and may have to accept some transitional taxonomies that include non-monophyletic taxa.”
Comments from Jaramillo: “YES. Everything lines up, parapatry, phylogenetic data etc. Observers in the field have been noting that there is a different bird up top and down below in the Sierra Nevada de Santa Marta for some time, so it is great to solidify that indeed there are two species, and that they appear not to be each other’s closest relatives. I think we are just hitting the tip of the iceberg with wrens, they will be the new tapaculos with many cryptic species to come, but unlike tapaculos the vocal data is much more complicated and difficult to decipher.
“The English Name Hermit Wood-Wren has been proposed for H. anachoreta, as well as Santa Marta Wood-Wren. A proposal for an English Name will be needed. Maybe avoiding another “Santa Marta xxxx” would be good?”