Proposal (689) to South American Classification Committee
Transfer Helmeted Woodpecker from Dryocopus to Celeus
Effect on SACC: This would transfer the Helmeted Woodpecker Dryocopus galeatus to Celeus.
New Information: Since Peters (1948), the Helmeted Woodpecker has been placed in the genus Dryocopus because of its similarity in plumage to members of that genus, in particular, the Lineated Woodpecker D. lineatus. ¬†Short (1982) noted plumage and structural characters of galeatus that were shared with Celeus, but he continued to maintain it in Dryocopus. ¬†The development of a robust molecular-based phylogeny and comparative analysis of vocalizations for Celeus (Benz and Robbins 2011) coupled with field experience by several observers suggested that the Helmeted Woodpecker was not a Dryocopus. ¬†This precipitated obtaining genetic material of galeatus that clearly place this unique woodpecker in Celeus (Benz et al. 2015; Figure 5):
Recommendation: The molecular data clearly establish that the Helmeted Woodpecker is a member of Celeus. The strikingly similar plumage pattern shared with sympatric Lineated Dryocopus lineatus and Robust Campephilus robustus woodpeckers is likely due to mimicry, although that hypothesis needs to be tested (Benz et al. 2015).
Benz, B.W. and M.B. Robbins. 2011. Molecular Phylogenetics, Vocalizations, and Species Limits in Celeus Woodpeckers (Aves: Picidae). Molecular Phylogenetics and Evolution 61:29‚Äì44.
Benz, B.W., M.B. Robbins, and K.J. Zimmer. 2015. Phylogenetic relationships of the Helmeted Woodpecker (Dryocopus galeatus): A case of interspecific mimicry? Auk 132:939-950.
Peters 1948. Check-list of birds of the world. Vol. 6. Museum of Comparative Zoology, Harvard University Press, Cambridge, Massachusetts.
Short, L.L. 1982. Woodpeckers of the World. Delaware Museum of Natural History, Greenville, Delaware.
Mark Robbins, Kevin Zimmer, and Brett Benz, November 2015
Comments from Remsen: ‚ÄúYES.¬† Fascinating result, strong data, easy decision.‚Äù
Comments by Areta: ‚ÄúYES. A long awaited (and suspected) phylogenetic result, which is almost exactly replicated by Lammertink et al. (2015). Benz et al. (2015) and Lammertink et al. (2015) differ in the exact placement of galeatus although all other species sampled agree in their phylogenetic relationships. Where will we place galeatus? Lammertink et al. (2015) placed it as sister to flavus-obrieni-spectabilis, while Benz et al. (2015) placed it as sister to all sampled Celeus excepting torquatus-loricatus. I incline towards Benz et al. (2015) proposal given their better taxon and gene sampling.‚Äù
Comments from Stiles: ‚ÄúYES ‚Äì a neat study, fascinating result (but consistent with the mimicry hypothesis for Campephilus-Dryocopus parallel changes in coloration!)‚Äù
Additional comments from Brett Benz: ‚ÄúTo address Areta‚Äôs concerns regarding the phylogenetic position of galeatus within Celeus, I downloaded the ND2 sequences generated by Lammertink et al (2015) from GenBank to compare it to those of Benz et al (2015) and Dufort 2016. ¬†The Benz et al ND2 sequences differed from that produced by the Dufort study by only 2 base pairs, whereas the sequences generated by Lammertink differed by 6 and 12 base pairs (~0.5 to 1.1%), with the later sequence containing 5 unique amino acids at positions that are otherwise invariable within all of Celeus. Although visual inspection of the Lammertink ND2 sequences revealed several instances where base pairs were likely miscalled resulting in sequentially shifted codon positions (a pattern indicative of a dirty trace file from the sequencer), this is unlikely the source of differing topologies between studies, as the Dufort super matrix approach also recovered a different topology for Celeus and placement of galeatus. ¬†Both the Lammertink and Dufort studies partitioned sequence data by gene, whereas Benz (2015) partitioned the mtDNA data by codon position, allowing for greater model specificity at conservative 2nd positions. Thus, marker selection and data-partitioning strategies likely account for the topological differences among these studies. The artificially high node scores (all 100%) of the Lammertink et al. study illustrate the importance of careful model selection and attention to methodological detail.‚Äù
Comments from Stotz: ‚ÄúYES.¬† This is a stunning finding, but the supporting data are strong.‚Äù
Comments from Zimmer: ‚ÄúAs a co-author on the Benz et al 2015 paper, this one gets an expected YES vote from me.¬† The molecular data clearly establish phylogenetic relationships that vocal, morphometric, behavioral and ecological characters had all suggested, all of which were obscured by the remarkable convergence of plumage patterns.¬† I‚Äôll never forget spending several minutes looking at my first galeatus at Igua√ßu Falls NP back in the early 1990s and remarking to my tour group that despite the plumage pattern, this bird struck me as being a Celeus, a conviction that was only strengthened the first time that I heard one vocalize.¬† Not surprisingly, Ted Parker (ICBP Red Data Book, 1992) had already noted some morphological, vocal and behavioral similarities to Celeus, as, apparently, had Short before him.¬† Nice to get this fascinating case recognized.‚Äù
Comments from Pacheco: ‚ÄúYES. Surprising, but very well supported by the data.‚Äù
Comments from Jaramillo: ‚ÄúYES ‚Äì Not really surprising because people in the field have felt this was the case for a long time. So it is great to see a different dataset confirm this notion, which seemed preposterous given the plumage.‚Äù