Proposal (262) to South American Classification Committee
Transfer Picoides mixtus and P. lignarius to Veniliornis
Proposal: This proposal (and 263) would reflect better the conclusions of Moore et al. (2006)'s molecular study of Veniliornis and Picoides species. Rather different issues are involved in each proposal, so they are treated separately. A new linear order is needed, but this would vary depending on the outcome of the two votes, so a proposal is postponed for now.
Moore et al. (2006) showed predominantly black-and-white Picoides mixtus and P. lignarius to form part of a clade containing all Veniliornis species sampled (except V. fumigatus, discussed below). The relevant nodes have strong support. Certain Picoides-like plumage characters in these species were postulated by Moore et al. possibly to have resulted from convergent evolution. Notably, V. spilogaster, the sister of these two species, has similar plumage patterning to mixtus and lignarius, although more colorful.
Two possible treatments in light of this study are (i) merging Veniliornis into Picoides; or (ii) transferring P. mixtus and P. lignarius to Veniliornis. Making the latter change (plus moving V. fumigatus to Picoides) would make Veniliornis a monophyletic group, which is desirable, and would minimise changes. Veniliornis is already rather heterogeneous. Merging with Picoides would create an uncomfortably large genus and result in a change of name for a number of species.
A possible criticism of the recommended approach is that, despite the proposed changes, Picoides would remain paraphyletic. Veniliornis is sister to a group containing small North American Picoides species, with these two clades together sister to a group of larger North American Picoides species plus V. fumigatus. A re-assignment of genera within Picoides is likely to be necessary in the future, possibly with the resurrection of old genera and/or creation of new ones. However, many of the Eurasian taxa have not been sampled by Moore et al.'s team, so they did not propose wider-ranging changes. In any event, it seems likely that splitting of Picoides rather than lumping with Veniliornis will be the recommended approach when the time comes to avoid creating an unwieldy genus. Moving the two species in question here to Veniliornis was strongly recommended by Moore et al (2006) and is likely to be a stable long-term treatment.
Recommendation: YES emphatically.
MOORE, W. S., A. C. WEIBEL, AND A. AGIUS. 2006. Mitochondrial DNA phylogeny of the woodpecker genus Veniliornis (Picidae, Picinae) and related genera implies convergent evolution of plumage patterns. Biological Journal of the Linnean Society 87: 611-624.
Thomas Donegan, January 2007
Comments from Stiles: "YES. Although the Moore et al. study uses only 2 mitochondrial genes, other studies using nuclear genes are consistent with the results presented in different aspects. So, I think that the evidence for sending fumigatus to Picoides and mixtus and lignarius to Veniliornis looks pretty solid. I like the comments of the authors regarding the parallel recurrence of "modules" of plumage patterns among different members of a clade or family in response to ecological or other conditions - certainly this seems to occur from time to time in hummingbirds, and implies that one must be cautious in reading too much into plumage patterns!"
Comments from Nores: "YES. Me parece apropiado cambiarlo, no sólo por el análisis mitocondrial sino también por su apariencia y plumaje que resultan tan diferentes de los Picoides de Norte América. En principio yo hubiera sacado Picoides mixtus and P. lignarius del género Picoides y no los hubiera incluido en Veniliornis, pero si el análisis molecular indica que son afines con Veniliornis parece determinante. Género Dyctiopicus ya que no me parece."
Comments from Cadena: "YES. Although there's only one gene in the Moore et al. data set, that P. mixtus and P. lignarius are nested within Veniliornis is implied by at least two strongly supported nodes."
Comments from Robbins: "YES, Moore et al. provide convincing data to move mixtus and lignarius to Veniliornis."
Comments on woodpecker phylogeny from Laurent Raty: click.
Comments solicited from Bill Moore: "Although there is no doubt that the Genus Picoides will be split into two or more smaller genera, it is clear that the South and Central American clade comprising all species of Veniliornis except fumigatus but including Picoides lignarius and P. mixtus is monophyletic and should be named as a taxon at the level of genus. Regardless of how the North American and Eurasian species are ultimately grouped, the South American clade will certainly stand and can safely be recognized at this juncture. As Van Remsen has counseled, a classification is a dynamic thing that should be revised as evidence indicates. We shouldn't wait the outcome of studies on the Eurasian species; the probability that that would impact the monophyly of Veniliornis is near zero."
Comments from Jaramillo: "YES - Reading Moore et al, I was troubled by the fact that they did not sample any of the three-toed Woodpeckers (the true Picoides). Maybe it is because I first became interested in birds while growing up in Canada, but to me Picoides are the "three-toes" and nothing else! Reading the amazingly complete summary by Laurent Raty suggests that this is indeed the case, although the data are not all out to properly arrange the black-and-white woodpeckers as of yet. As such I am not troubled by the broad Picoides, which may be in fact a temporary state. But as Moore's comment states, that issue will unlikely impact the monophyly of Veniliornis, and his data is clear that the southern cone "Picoides" are really black-and-white Veniliornis. Interestingly the southern cone "Picoides" not only show convergence through plumage, but vocally they also have converged on a trill/chatter that reminds one of a Downy Woodpecker. A tangential remark here is that the Bolivian "Picoides" lignarius is almost certainly not the same species as the southern lignarius."
Comments from Pacheco: "YES. Embora a proposićčo derive apenas da análise de dois diferentes genes mitocondriais, me parece acertado subordinar o par de espécies ao gźnero Veniliornis. Como complemento, cabe citar, ao menos, que a vocalizaćčo similar entre mixtus e Veniliornis spp. corrobora essa afinidade."