Proposal (300) to South American Classification Committee

 

Change the linear sequence of thamnophilid genera: move Drymophila to follow Hypocnemis

 

BackgroundDrymophila currently precedes Terenura in the checklist, and is separated from Hypocnemis in the sequence by five genera. In a molecular phylogeny, Bates et al. (1999) found that Drymophila was sister to Hypocnemis, and not close to Terenura.

 

Effect on South American CL: The sequence will better reflect the evolution of Drymophila and Hypocnemis antbirds by emphasizing their sister relationship.

 

Recommendation: I recommend voting "Yes." For what its worth, this sister relationship makes sense to me as Drymophila devillei appears much like a longer tailed version of a Hypocnemis peruviana, and it shares a raspy voice with Hypocnemis as well.

 

References:

Bates, J. M., S. J. Hackett, & J. M. Goerck. 1999. High levels of mitochondrial DNA differentiation in two lineages of antbirds (Drymophila and Hypocnemis). Auk 116: 1093-1106.

 

Daniel Lebbin, August 2007

 

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Comments solicited from Robb Brumfield: "Brumfield et al. (2007) found reasonably high support (1.0 Bayesian posterior probability, 77% maximum likelihood bootstrap, 70% parsimony bootstrap) for a Drymophila-Hypocnemis sister relationship based on an analysis of 2,977 base pairs. Irestedt et al. (2004) did not find this sister relationship. Their analysis of 2,173 bp found weak support for a Drymophila/Myrmeciza hemimelaena sister relationship (0.59 Bayesian posterior probability), with Hypocnemis sister to this clade (0.93 Bayesian posterior probability). Brumfield et al. found M. hemimelaena to be sister to Cercomacra, and this clade is sister to the Hypocnemis/Drymophila clade. I suspect the different results between the two studies are due largely to taxonomic sampling and the amount of the data -- the Brumfield et al. study included 70 species, the Irestedt et al. study 51 thamnophilids. Overall, I think placing Hypocnemis and Drymophila together in a linear classification is supported by the molecular data. The two are also similar vocally.

 

Brumfield, R. T., J. G. Tello, Z. A. Cheviron, M. D. Carling, and N. Crochet. 2007. Phylogenetic conservatism and antiquity of a tropical specialization: army-ant-following in the typical antbirds (Thamnophilidae). Molecular Phylogenetics and Evolution (in press).

Irestedt, M., FjeldsĆ, J., Nylander, J.A.A., Ericson, P.G.P., 2004. Phylogenetic relationships of typical antbirds (Thamnophilidae) and test of incongruence based on Bayes factors. BMC Evol. Biol. 4, Art. No. 23."

 

Comments from Stiles: "YES. Although the evidence for a Drymophila-Hypocnemis clade is a bit equivocal, that in favor of a Drymophila-Terenura relationship is zero; and I agree with Brumfield that Drymophila has a similar "style" of calls to Hypocnemis. If you shorten the tails of Drymophila, the two even look pretty similar."

 

Comments from Stotz: "YES. Drymophila and Hypocnemis have always seemed similar to me, and while the molecular work may not have clinched this relationship, the complete lack of evidence for alternatives, and especially the status quo, makes me think this is the way to go."

 

Comments from Jaramillo: "YES - Plumage similarity between these genera has caught my eye, although as we know plumage patterns can be convergent. But the mix of molecular data, plumage, and voice makes me think this is a good course of action, the status quo on the other hand is not supported by anything really."

 

Comments from Robbins: "YES. I am presuming that the differences between the Brumfield et al. (2007) and Irestedt et al. (2004) results are simply related to the density of taxon sampling."

 

Comments from Nores: "NO. Para mí la diferencia entre los resultados de Irestedt et al. (2004) y Brumfield et al. (2007) están más relacionados con problemas en los análisis moleculares, que en "taxonomic sampling and the amount of the data" or "density of taxon sampling". De allí, que cuando hay diferencias entre dos análisis moleculares, como en este caso, no puedo saber cuál de los dos tiene razón y prefiero esperar por un tercer análisis (que desempate) para sacar conclusiones."

 

Comments from Pacheco: "YES. As similaridades na morfologia, comportamento e vocalizaćões entre o par Hypocnemis-Drymophila nčo parecem ser fruto casual de uma convergźncia. Quero crer que os resultados de Brumfield e colaboradores corroborem o esperado."

 

Comments from Remsen: "YES. Genetic data solidly support sister relationship between the two, confirming suspicions aroused by plumage similarities. However, whether Drymophila should follow Hypocnemis or the reverse cannot really be determined from the taxon-sampling in Bates et al. (1999). Moving Hypocnemis rather than Drymophila actually causes less disruption to the traditional sequence of presumably closely related genera, and so I will do this rather than the proposed move of Drymophila 'down'."

 

Comments from Zimmer: "YES. Even if the molecular evidence is a mixed bag, there is absolutely no support for a Drymophila-Terenura clade, and, as pointed out by others, there are a number of plumage and vocal similarities between Drymophila and Hypocnemis (and not just with Drymophila devillei; see also D. ochropyga)."