Proposal (674) to South American Classification Committee
Transfer Chordeiles nacunda and Chordeiles pusillus to Podager
Effect on SACC: Move two taxa out of Chordeiles into Podager
Background: Han et al. (2010) genetic data demonstrated that large Podager nacunda was sister to the petite Chordeiles pusillus and recommended that Podager be subsumed into Chordeiles. As a result, SACC (proposal 467) moved nacunda into Chordeiles.
New Information: Sigurdsson and Cracraft’s (2104) genetic data corroborated that nacunda was sister to Chordeiles pusillus; however, they suggested that the two be placed in the genus Podager. Given branch lengths (see Fig. 4 in their paper) I’m not sure why they suggested that Podager be resurrected. As usual, generic allocations can be subjective.
Recommendation: Given that nacunda and pusillus capture the full range of Chordeiles plumage characters and size and branch lengths among the various clades are not great, I see no reason to recognize Podager as a genus. Thus, I recommend a “no” vote to this proposal.
Han, K-L., M.B. Robbins, and M.J. Braun. 2010. A multi-gene estimate of phylogeny in the nightjars and nighthawks (Caprimulgidae). Molecular Phylogenetics and Evolution 55:443-453.
Sigurdsson, S. and J. Cracraft. 2014. Deciphering the diversity and history of New World nightjars (Aves: Caprimulgidae) using molecular phylogenetics. Zoological Journal of the Linnean Society. 170:506-545.
Mark Robbins, July 2015
Comments from Remsen: “NO. I agree with Mark’s rationale and see no reason to change unless provided with better rationale.”
Comments from Areta: "NO. Vocally, morphologically and behaviorally it makes sense to retain pusillus and nacunda in Chordeiles."
Comments from Zimmer: “NO, for reasons stated by Mark in the proposal.”
Comments from Stiles: “NO. I agree with Mark here, as in general I prefer diagnosable genera, even if large, to splitting into smaller genera that cannot be sensibly diagnosed.”
Comments from Nores: “YES. Genetically and somehow also for behavior, Podager is, for me, different from Chordeiles.”
Comments from Jaramillo: “YES. As noted, delineation of genera is subjective. I do think that the evolutionary history in the phylogeny is important. Morphologically, unless I am off on this, it seems that nacunda and pusillus share a different wing structure than true Chordeiles: they are round-winged. They also seem to share a similar throat pattern showing a narrow white band on the throat. Finally, these two perch commonly on the ground, which is the default, whereas Chordeiles tend to default to a branch or post. Voice is not very useful in the case of this group, as I see very little to unite or separate anything in this group based on voice. They all sound weird and froglike I guess, but that is about it. The vocal differences between sisters such as Antillean and Common seem pretty big to me, and not all that similar for example.”
“On the whole, I think that taking these two out into Podager creates a much more uniform Chordeiles. I also think that even without the molecular data one could have come up with pusillus being sister to nacunda, so there is some consistency within Podager as well. If it has to be simplified to wing shape and molecular data, that could be it, but I think that Podager is useful and worth resuscitating.”