Proposal (422) to South American Classification Committee
Lump Anisognathus melanogenys with A. lacrymosus
Effect of Proposal: If it passes, this proposal would result in a Santa Marta endemic, Anisognathus melanogenys, being lumped with A. lacrymosus, a widespread Andean species. We recommend rejecting this proposal based on Donegan & Avendaño (2010).
Discussion: A. melanogenys has been treated as a subspecies of A. lacrymosus by various authors (e.g. Hellmayr 1936, Zimmer 1944, Storer 1970, Isler & Isler 1999) or as part of a superspecies together with A. lacrymosus (Sibley & Monroe 1990). However, the majority of recent publications, including SACC, recognise it a specifically distinct (e.g. Meyer de Schauensee 1964, 1966, Hilty & Brown 1986, Fjeldså & Krabbe 1990, Ridgely & Tudor 1994, 2009, Dickinson 2003, Restall et al. 2006, Salaman et al. 2009). Such split or lumped treatments have been based on a subjective consideration of plumage without any previous detailed study of voice or biometrics.
Donegan & Avendaño (2010) analysed plumage, voice and biometrics of A. melanogenys and A. lacrymosus in connection with the description of a new subspecies endemic to high elevations of the Yariguíes Mountains. These analyses support maintaining species rank for A. melanogenys. A. melanogenys has a longer bill than A. lacrymosus, with a different, more elongated shape. The Santa Marta endemic is fully diagnosable in bill length from proximate populations, A.l. melanops, A.l. pallididorsalis and A.l. tamae (and A.l. lacrymosus), although is not fully diagnosable in this measurement from some of the southern races of A. lacrymosus. In contrast, only average differences in biometrics were found among A. lacrymosus subspecies. In plumage, the combination of a cerulean blue crown and absence of a yellow nuchal ’tear’ in A. melanogenys involves differences in both pattern and coloration from all A. lacrymosus taxa. A. melanogenys further lacks strong blue feathering on its rump and has paler yellow underparts, and greener-blue upperparts and remiges compared to A. lacrymosus. In contrast, although various allopatric A. lacrymosus taxa constitute phylogenetic species (based on plumage), none are known to occur in sympatry and morphological differences between populations do not approach the differentiation shown between A. melanogenys and other taxa.
Turning to voice, A. melanogenys calls have a subtle but consistently different note shape (and call length) compared to A. lacrymosus populations, being delivered faster and appearing as virtually a straight line (as opposed to a more skewed upstroke or up-down stroke) on sonograms.
The Santa Marta Mountains are isolated geographically from the Andes and harbour a number of endemic high-elevation birds considered specifically distinct from populations in the Andes (e.g. Krabbe 2008), of which A. melanogenys appears to be an example. These differences are supported by recent phylogenetic analysis presented by Sedano and Burns (2009), suggesting that A. melanogenys represents a distinct lineage, which is sister to a clade comprising A. igniventris and A. lacrymosus.
Recommendation: We recommended maintaining species rank for A. melanogenys and A. lacrymosus, with no further splits to A. lacrymosus, applying a Biological Species Concept. This would be reflected by a “NO” vote.
Donegan, T.M. & Avendaño, J.E. 2010. A new subspecies of mountain tanager in the Anisognathus lacrymosus complex from the Yariguíes Mountains of Colombia. Bull BOC 130(1): 13-32.
Sedano & Burns. 2009. Are the Northern Andes a species pump for Neotropical birds? Phylogenetics and biogeography of a clade of Neotropical tanagers (Aves: Thraupini) Journal of Biogeography. http://www.bio.sdsu.edu/pub/burns/Sedano&Burnsinpress.pdf
Other references are cited in these papers.
Thomas Donegan & Jorge Enrique Avendaño, March 2010
Comments from Robbins: “NO to the lumping of melanogenys. I suspect genetic data will demonstrate not only that melanogenys is distinct, but northern and southern (i.e., across the Marañón) main change Andean forms will also be quite different corresponding with plumage differences.”
Comments from Stiles: “NO. Biogeography, plumage, vocalizations and genetics all support maintaining melanogenys as a separate species.”
Comments from Remsen: “NO. The Sedano & Burns (2010) phylogeny pretty much makes this a moot point – if you can see the paste-in below, melanogenys and lacrymosus are not sisters.”
Comments from Nores: “NO. De todos modos yo no veo necesaria este tipo de propuesta que no modifica la SACC list y es aceptada por la mayoría de los autores. Sería como proponer: Lump Thraupis sayaca with T. episcopus pero inmediatamente decir que no porque son diferentes.”
Comments from Schulenberg: “NO. The position of melanogenys with respect to lacrymosus (Sedano and Burns 2010) was a surprise to me, but I likely would have voted "no" on this proposal even without that bit if information.”
Comments from Cadena: “NO, and I agree with Manuel that proposals like this one do not seem necessary. These species are very different and nobody has recently questioned their treatment as separate species.”