Proposal (467) to South American Classification Committee
Transfer Podager nacunda to the genus Chordeiles
Han et al. (2010) published a molecular based phylogeny of Caprimulgidae from more than 60% of caprimulgid species and 14 of 16 currently recognized genera. The taxon sampling was broad and included all morphologically divergent lineages. New World taxa were particularly well represented. DNA sequences were collected from the entire mitochondrial DNA cytochrome b gene and parts of two nuclear genes (myelocytomatosis viral oncogene homolog and growth hormone). All analyses of the 72 ingroup plus outgroup taxa were conducted on the 4179 characters. The Han et al. (2010) phylogeny was well resolved and in substantial agreement with all previous molecular work on the family (Sibley and Ahlquist, 1990; Mariaux and Braun, 1996; Barrowclough et al., 2006; Larsen et al., 2007; Braun and Huddleston, 2009).
In proposing a new classification, Han et al. (2010) used the following criteria: foremost, all named taxa represented monophyletic groups. Second, for stability of the named taxa, whenever possible, currently recognized taxa were retained, and when more than one partitioning scheme for a clade was plausible, they opted for the one that was more likely to remain viable in the face of new data.
Within core caprimulgids, four strongly supported major clades (3 New World, 1 Old World) provided a natural partitioning scheme.
Based on the Han et al. (2010) molecular data, within the monophyletic Chordeiles nighthawk clade, Podager nacunda was sister to C. pusillus. Thus, Podager should be transferred to the genus Chordeiles Swainson 1831, which has priority over the monotypic Podager (Peters 1940). The separation of this clade from Lurocalis and Nyctiprogne makes the Chordeilinae nonmonophyletic.
Here is the relevant portion of the tree from Han et al.:
Barrowclough, G.F., Groth, J.G., Mertz, L.A. 2006. The RAG-1 exon in the avian order Caprimulgiformes: phylogeny, heterozygosity, and base composition. Mol. Phylogenet. Evol. 41:238–248.
Braun, M.J., Huddleston, C.J. 2009. A molecular phylogenetic survey of caprimulgiform nightbirds illustrates the utility of non-coding sequences. Mol. Phylogenet. Evol. 53:948–960.
Han, K.-L., Robbins, M.B., Braun, M.J. 2010. A multi-gene estimate of phylogeny in the nightjars and nighthawks (Caprimulgidae). Mol. Phylogenet. Evol. 55:443-453.
Larsen, C., Speed, M., Harvey, N., Noyes, H.A. 2007. A molecular phylogeny of the nightjars (Aves: Caprimulgidae) suggests extensive conservation of primitive morphological traits across multiple lineages. Mol. Phylogenet. Evol. 42:789–796.
Mariaux, J., Braun, M.J. 1996. A molecular phylogenetic survey of the nightjars and allies (Caprimulgiformes) with special emphasis on the potoos (Nyctibiidae). Mol. Phylogenet. Evol. 6:228–244.
Peters, J.L. 1940. Checklist of Birds of the World. Harvard University Press, Cambridge.
Sibley, C.G., Ahlquist, J.E. 1990. Phylogeny and Classification of Birds: A Study in Molecular Evolution. Yale University Press, New Haven, London.
Mark Robbins, September 2010
Comments from Stiles: “YES – again, this clade seems strongly supported and although it is the most divergent of all, I see no sense in splitting off Podager given the great similarity of minor with acutipennis in particular, whereas inclusion of Podager in Chordeiles does not augment the variation in the enlarged genus to the point of undiagnosability.”
Comments from Nores: “YES. El análisis molecular de Han et al. muestra claramente que Podager nacunda está estrechamente relacionado con Chordeiles. Es más, parece estar más relacionado con Chordeiles pusillus, que lo que Chordeiles pusillus está con las otras especies congenéricas.”
Comments from Remsen: “YES. Preferable to merging pusillus into Podager or recognizing a monotypic genus for pusillus. [As an aside, who would have predicted the sister to acutipennis is rupestris, not minor – or does that makes more sense from voice?]
Comments from Zimmer: “YES. This move appears to be strongly supported by the data, and I agree that nacunda is more one end of a spectrum than truly divergent compared to other members of Chordeiles. In answer to Van’s aside, I would say that vocal similarities would argue for a closer relationship between acutipennis and rupestris than between the former and minor.”
Comments from Pacheco: “YES. I consider this transfer – compared to other possibilities - the most appropriate measure. It would be very appropriate in this case; check with Edward Dickinson to see which of the two genera has priority? Chordeiles (see AOU Checklist, p. 267) and Podager are both dated from 1832.”
Comments from Jaramillo: “YES. Although a big beefy one, Podager is by all means a nighthawk and really only different in size. In terms of plumage pattern and behavior it fits right in, I would say. Addition of nacunda to Chordeiles does not make the genus so diverse that it is undiagnosable, so I see no reason to buck the data.”
Comments from Pérez: “YES, I think this is a strongly supported clade and, with the exception of size, Podager is very similar to other nighthawk species. Which name has priority is a tricky thing. Although Peters showed Chordeiles was described by Swainson in Swainson & Richardson’s Fauna Bor.-Am. 2 in 1831(1832) and Podager by Wagler in 1832 (Isis von Oken, number 3), Cory (1918) in the Catalogue of Birds of the Americas dated Swainson’s` Chordeiles in 1831. This information will support priority of Chordeiles over Podager, but appearance of 1832 within parentheses, as shown in Peters, might indicate actual publication in 1832.”