Proposal (788) to South American Classification Committee
Transfer Gray Noddy (Procelsterna albivitta) to the genus Anous
The SACC checklist (Remsen et al. 2018; below) currently lists 3 of the 5 species of noddies in two genera: Anous Stephens 1826 for the dark-plumaged species stolidus, minutus, and tenuirostris, and Procelsterna Lafresnaye 1842 for the lighter-plumaged species cerulea and albivitta (Dickinson and Remsen 2013), an arrangement that has long been recognized (e.g., Peters 1934).
Anous stolidus (Brown Noddy)
Anous minutus (Black Noddy)
Procelsterna albivitta (Gray Noddy)
Cibois et al. (2016) produced a molecular phylogeny of noddies using two mitochondrial and one nuclear loci. They sampled each of the five noddy species and included outgroup taxa from Sterna, Thalasseus, Gygis, and Larus. Combined multilocus analyses yielded strong support for a species-level topology with the five noddy species forming a clade and Procelsterna embedded within Anous. A mitochondrial-only analysis produced the same topology as the combined analysis, and the nuclear-only analysis yielded an unresolved topology.
Figure 2 (combined multilocus BEAST analysis) from Cibois et al. (2016)
Cibois et al. (2016) recommended the following:
"Based on our molecular phylogeny, we propose here to merge all noddies into the genus Anous Stephens 1826, and to consider Procelsterna Lafresnaye 1842 as a junior synonym. The alternative would be to retain the genus Procelsterna for the Grey and Blue Noddies and the genus Anous for the Brown Noddy (the type species), and to resurrect the genus Megalopterus Boie, 1826 for the Lesser and Black Noddies (type species M. tenuirostris Temminck, 1823). However, the morphological similarities of the five species provide strong support for a single genus that includes all noddies."
The tree topology here is driven primarily by the mitochondrial DNA signal. However, that signal is strong and the relevant tree splits are quite deep, which should reduce concerns that the mitochondrial gene tree might not reflect evolutionary history. Given the tree topology above, the taxonomic case for merging Procelsterna into Anous seems relatively straightforward. The specific epithet albivitta would change to albivittus to match the masculine gender of Anous.
A YES vote is recommended.
This merger was accepted by NACC (Chesser et al. 2017).
Chesser, R. Terry, Kevin J. Burns, Carla Cicero, Jon L. Dunn, Andrew W. Kratter, Irby J. Lovette, Pamela C. Rasmussen, J. V. Remsen, Jr., James D. Rising, Douglas F. Stotz, and Kevin Winker (2017) Fifty-eighth supplement to the American Ornithological Society's Check-list of North American Birds. The Auk: July 2017, Vol. 134, No. 3, pp. 751-773.
Cibois, A., Thibault, J-C., Rocamora, G., and E. Pasquet. 2016. Molecular phylogeny and systematics of Blue and Grey Noddies (Procelsterna). Ibis 158:433-438.
Dickinson, E. C., and J. V. Remsen, Jr. (eds.). 2013. The Howard and Moore complete checklist of the birds of the World. Vol. 2. Non-passerines. Aves Press, Eastbourne, U.K., 461 pp.
Peters, J. L. 1934. Check-list of birds of the world, vol. 2. Harvard University Press, Cambridge, Massachusetts.
Remsen, J. V., Jr., J. I. Areta, C. D. Cadena, S. Claramunt, A. Jaramillo, J. F. Pacheco, J. Perez-Emán, M. B. Robbins, F. G. Stiles, D. F. Stotz, and K. J. Zimmer. Version 11 April 2018. A classification of the bird species of South America. American Ornithologists' Union. http://www.museum.lsu.edu/~Remsen/SACCBaseline.htm
David L. Slager, April 2018
Comments from Remsen: “YES. This merger is required by the new DNA-based phylogeny.”
Comments from Jaramillo: “YES – I had also written a proposal for this change and agree with the recommendations here.”
Comments from Pacheco: “YES. The external similarity of the five species, with endorsement of the genetic data, gives satisfactory support for treatment in single genus.”
Comments from Areta: “YES, morphological similarities and strong support in key nodes of the phylogenetic tree support the merger over the three-genera treatment.”