Proposal (723) to South American Classification Committee

 

Revise the linear sequence of Orders

 

This proposal would revise the higher-level linear sequence as follows:

 

(a) Move Strigiformes to precede Trogoniformes
(b) Move Accipitriformes to precede Strigiformes
(c) Move Eurypygiformes and Phaethontiformes to precede Sphenisciformes
(d) Reverse the linear sequence of Podicipediformes and Phoenicopteriformes
(e)
Move Pterocliformes and Columbiformes to follow Podicipediformes
(f) Move Cuculiformes, Caprimulgiformes, and Apodiformes to follow Columbiformes
(g) Move Gruiformes and Charadriiformes to precede Eurypygiformes

(h) Move Opisthocomiformes to precede Gruiformes

 

 

Background:

The higher-level phylogeny of birds has been addressed over the past 25 years by genetic studies using various types of data and taxon sampling (e.g., Sibley and Ahlquist 1990, Groth and Barrowclough 1999, Fain and Houde 2004, Hackett et al 2008, McCormack et al. 2013, Kimball et al. 2013, Jarvis et al. 2014, Burleigh et al. 2015, Suh et al. 2015, Prum et al. 2015). The trees produced by these studies have been at odds with traditional ideas of avian phylogeny in a variety of ways, some of which have been widely adopted. For example, it is now generally recognized that the Galliformes and Anseriformes are sister taxa and together (as Galloanseres) are the sister group to all other extant non-paleognath birds, or Neoaves (Sibley and Ahlquist 1990, Groth and Barrowclough 1999, et al.). Non-traditional results among the Neoaves have been slower to gain acceptance, primarily because they had been found in only a single study (e.g., in Hackett et al. 2008; Fig. 1) or had been weakly supported. However, recent phylogenomic studies, especially Jarvis et al. (2014; Fig. 2) and Prum et al. (2015; Figs. 3 and 4), have provided strong support for several non-traditional results obtained in one or more previous studies. Several clades in the higher-level phylogeny of Neoaves are now reasonably well supported, including large core waterbird and core landbird clades. The core waterbird clade consists of the Gaviiformes, Sphenisciformes, Procellariiformes, Ciconiiformes, Suliformes, and Pelecaniformes, and the core landbird clade consists of the Accipitriformes, Strigiformes, Coliiformes, Leptosomiformes, Trogoniformes, Upupiformes, Bucerotiformes, Coraciiformes, Piciformes, Cariamiformes, Falconiformes, Psittaciformes, and Passeriformes.

 

 

Figure 1. Maximum-likelihood phylogeny from Hackett et al. (2008).

 

Figure 2. Maximum-likelihood phylogeny from Jarvis et al. (2014).

 

 

Figure 3a. First part of Bayesian phylogeny from Prum et al. (2015).

 

 

Figure 3b. Second part of Bayesian phylogeny from Prum et al. (2015).

 

 

 

Figure 4. Maximum likelihood phylogeny in the supplemental material from Prum et al. (2015). Yellow dots indicate nodes with <70% bootstrap support.

As noted by Suh et al. (2015), the diversification of Neoaves seems to consist largely of three radiations: a poorly resolved initial radiation at the base of the Neoaves (consisting of Podicipediformes, Phoenicopteriformes, Columbiformes, Pterocliformes, Mesitornithiformes, Cuculiformes, Musophagiformes, Otidiformes, Caprimulgiformes, Apodiformes, Opisthocomiformes, Gruiformes, Charadriiformes, and perhaps Eurypygiformes and Phaethontiformes, although these latter two are likely the sister group to the core waterbirds) followed by the better resolved radiations of the core waterbirds and core landbirds. Thus, we have relatively strong support for the makeup and placement of the core waterbirds and landbirds, but only poor to moderate support for the placement of most other avian groups.

 

The following motions propose to change the SACC higher-level linear sequence based on the new phylogenetic studies, relying more heavily on the most data-rich studies, those of Jarvis et al. (2014) and Prum et al. (2015). Subproposals (a)-(b) would place together in the linear sequence all orders that constitute the core landbirds. Subproposal (c) would do the same for the core waterbirds, and place the Eurypygiformes and Phaethontiformes so as to precede the core waterbirds.  Subproposal (d) is a bookkeeping change that should have been made some time ago. Subproposals (e)-(h) would: (1) place together in the linear sequence all other orders that appear to constitute the initial radiation of Neoaves, and (2) place these orders in a linear sequence that seems to best represent the bulk of the evidence. Given the uncertainty at the base of the tree, the placements of these latter orders differ somewhat in the various studies, but many of these different placements can be accommodated in a linear sequence.

 

An appendix detailing the current SACC linear sequence, the linear sequence that would result from approval of proposals (a)-(d), the linear sequence that would result from approval of all proposals, and the linear sequence that would result from following the Bayesian tree in Prum et al. (2015) appears at the end of this proposal.

 

 

(a) Move Strigiformes to precede Trogoniformes, and (b) move Cathartiformes + Accipitriformes to precede Strigiformes.

 

One of the most striking results of the recent DNA sequence studies, such as the intron-based study of 169 species (Hackett et al 2008), the whole-genome study of 48 species (Jarvis et al 2014), and the target-enrichment study of 198 species (Prum et al. 2015), and not found in Sibley and Ahlquist, was the lack of a sister relationship between the falcons and caracaras on the one hand and the hawks, eagles, kites, and vultures on the other. SACC recently removed the Falconiformes sensu stricto from the Accipitriformes and placed them towards the end of the linear sequence as sister to a Passeriformes/Psittaciformes clade, but the Cathartiformes+Accipitriformes were left in their former position between the core waterbirds and the Gruiformes sensu lato. Likewise, SACC maintained the Strigiformes in their traditional placement between the Cuculiformes and the Caprimulgiformes.

 

These new moves would reflect the phylogenetic relationships of the core landbird clade mentioned above and would result in the following sequence at the end of the classification: Cathartiformes, Accipitriformes, Strigiformes, Trogoniformes, Coraciiformes, Galbuliformes, Piciformes, Cariamiformes, Falconiformes, Psittaciformes, and Passeriformes. This sequence is in agreement with the phylogenetic trees in Hackett et al. (2008), Jarvis et al. (2014), and Prum et al. (2015), among others.

 

According to Hackett et al. (2008), the Strigiformes are sister to the Coliiformes, and this clade is sister to a clade consisting of the Leptosomiformes, Trogoniformes, Upupiformes, Coraciiformes, and Piciformes. The Accipitriformes sensu lato (incl. Cathartidae) are sister to this entire clade. Although these results received poor bootstrap support (< 50%), all of the more recent studies support this result, some with strong support.

 

For example, Jarvis et al. (2014), in their whole genome study, recovered a clade consisting of the Coliiformes, Leptosomiformes, Trogoniformes, Bucerotiformes, Coraciiformes, and Piciformes (Coraciimorphae, sensu Jarvis et al.), with the Strigiformes sister to this clade, and the Accipitriformes sensu lato sister to this larger clade. Bootstrap support for the entire clade (“Afroavessensu Jarvis et al.) was 100%, support for the Accipitriformes as sister to all other taxa was 100%, and support for the Strigiformes as sister to the rest (except for the Accipitriformes) was 84%. Prum et al. (2015) also recovered this arrangement, except that the Accipitriformes were sister to a clade consisting of the Strigiformes and Coraciimorphae + Cariamiformes, Falconiformes, Psittaciformes, and Passeriformes (these four orders constituting the Australaves), making “Afroaves” paraphyletic. Posterior probabilities for their results were all 1.0 and ML bootstraps were all >70% (finer resolution was not provided for the bootstraps).

 

The current SACC linear sequence has a monophyletic Coraciimorphae but, as noted above, places the Cathartiformes+Accipitriformes far from the Coraciimorphae and also separates the Strigiformes from these two groups. By moving the Strigiformes to precede the Trogoniformes, and then moving the Cathartiformes+Accipitriformes to precede the Strigiformes, SACC would achieve the following: (1) make the core landbird clade monophyletic; (2) place the Strigiformes in the correct position as sister to the Coraciimorphae; and (3) position Cathartiformes+Accipitriformes in the linear sequence to reflect a sister relationship with the rest of “Afroaves” (as in Jarvis et al. 2014) or to reflect a sister relationship with the Strigiformes+Coraciimorphae+Australaves clade (as in Prum et al. 2015).

 

(c) move Eurypygiformes and Phaethontiformes to precede Sphenisciformes.

 

Numerous studies have identified a core waterbird clade consisting of the Gaviiformes, Procellariiformes, Sphenisciformes, Pelecaniformes, Suliformes, and Ciconiiformes, but not the Phaethontiformes, which are currently embedded within the waterbird clade in the SACC linear sequence. Sibley and Ahlquist (1990), using DNA-DNA hybridization, found that their representatives of these orders formed a monophyletic group, that this group of waterbirds was embedded deep within the Neoaves, that the Phaethontiformes were the sister group to this waterbird clade, and that within the clade the Gaviiformes and Procellariiformes were sister groups. Hackett et al. (2008) also found that the Gaviiformes, Procellariiformes, Sphenisciformes, Pelecaniformes, Suliformes, and Ciconiiformes formed a clade, with reasonably strong support (89% bootstrap), and that this clade was embedded within the Neoaves. However, the Gaviiformes were sister to the rest of this group (94% bootstrap).

 

The presence of this core waterbird clade has been remarkably consistent in the recent studies. The UCE-based study of McCormack et al. (2013) found strong support for the waterbird clade, and Kimball et al. (2013) also recovered this clade. Jarvis et al. (2014) found that the Gaviiformes, Procellariiformes, Sphenisciformes, Pelecaniformes, and Suliformes formed a clade, and presumably the Ciconiiformes would have formed part of this group had a representative been included in the study. Burleigh et al. (2015) and Prum et al. (2015) found a waterbird clade of the same composition but including Ciconiiformes, with moderate to strong support: 73% bootstrap in Burleigh et al., 1.0 pp and >70% bootstrap in Prum et al.

 

 Three of the recent studies provided support for Sibley’s result of the Phaethontiformes as sister to the waterbird clade. In Jarvis et al. (2014) and Prum et al. (2015), the Phaethontiformes and the Eurypygiformes formed a clade that was sister to the waterbird clade, with moderate to strong support (70% bootstrap in Jarvis et al., 1.0 pp and >70% bootstrap in Prum et al.), and this clade was also sister to the waterbird clade in at least one of the trees in Kimball et al. (2013), although with poor support.

 The Eurypygiformes have generally been difficult to place, and the results of Jarvis et al. and Prum et al. provide some of the only reasonable support for placement of this order. Hackett et al. (2008), for example, had them as sister to the Caprimulgiformes-Apodiformes clade, but support was not strong (61% bootstrap). Several trees in Kimball et al. (2013) placed them as sister to the Phaethontiformes, as did McCormack et al. (2013), although their placement beyond this was uncertain.

 

 All studies provide strong support for the monophyly of the Gaviiformes, Procellariiformes, Sphenisciformes, Pelecaniformes, Suliformes, and Ciconiiformes as a “core waterbirds” group, with reasonable support for the Phaethontiformes and Eurypygiformes as sisters to this group. The current SACC sequence places the Sphenisciformes directly after the Podicipediformes and Phoenicopteriformes. Next in the linear sequence are the Procellariiformes, Phaethontiformes, Ciconiiformes, Suliformes, and Pelecaniformes; this is the core waterbird group identified by the genetic studies except for the presence of the Phaethontiformes. By moving the Eurypygiformes and Phaethontiformes to precede the Sphenisciformes, SACC would achieve the following: (1) make the core waterbird group monophyletic, and (2) place Eurypygiformes and Phaethontiformes in the correct position as indicated by Jarvis et al. and Prum et al., as sister group to the core waterbirds.

 

(d) Reverse the linear sequence of Podicipediformes and Phoenicopteriformes.

 

SACC has long recognized Podicipediformes + Phoenicopteriformes as a clade, but for some reason the order with more genera and species (Podicipediformes = 6 genera, 22 species) precedes the one with fewer genera and species (Phoenicopteriformes = 1 genus, 6 species) in the classification, in contradiction to the conventions for linear sequencing. This subproposal corrects this error.

 

(e) Move Columbiformes to follow Podicipediformes, and (f) move Cuculiformes, Caprimulgiformes and Apodiformes to follow Columbiformes.

 

In the current SACC sequence, the Columbiformes and Cuculiformes (with Opisthocomiformes, see below, in between) precede the Strigiformes, and the Caprimulgiformes and Apodiformes follow the Strigiformes. If subproposals (a) and (h) pass, these groups will occur together in the linear sequence.

 

Hackett et al. (2008), Jarvis et al. (2014), and Burleigh et al. (2015) found close relationships among the Columbiformes, Pterocliformes, Mesitornithiformes, Phoenicopteriformes, and Podicipediformes, Jarvis et al. with strong support. The relevant discrepancy in their respective results was the addition of the Phaethontiformes to the clade in Hackett et al (2008) and Burleigh et al. (2015), although with poor support. The position of the Phaethontiformes well outside of this clade (as or in the sister group to the core waterbird clade) in the studies of Sibley and Ahlquist (1990), Kimball et al. (2013), Jarvis et al (2014), and Prum et al. (2015) along with the poor support for this clade in Hackett et al. (2008) and Burleigh et al. (2015), suggests that the placement as sister to the waterbirds, as above in (c), is likely more appropriate.

 

Other orders that have consistently shown up near the base of the Neoaves are the Cuculiformes, Caprimulgiformes, and Apodiformes. In Jarvis et al. (2014), representatives of these orders were placed in the clade that is sister to all other Passerea (which encompasses all Neoaves except for their Columbea), with reasonably strong bootstrap support (91%). In Hackett et al (2008), the Caprimulgiformes formed part of the clade that includes most of the orders in the Columbea of Jarvis et al., mirroring in part the Metaves of Fain and Houde (2004), although bootstrap support was weak (< 50%). The Cuculiformes, Gruiformes, and Otidiformes formed a clade that was sister to the Musophagiformes + the core waterbird clade – a result that received reasonable support (81%) although this support was much reduced (<50%) in the extended dataset of Kimball et al. (2013). There was little support for relationships of these orders in McCormack et al. (2013) and Burleigh et al. (2015). Prum et al. (2015) found the Caprimulgiformes + Apodiformes to be sister to all other Neoaves, with their Columbaves (including Cuculiformes, Otidiformes, Musophagiformes, Columbiformes, Pterocliformes, and Mesitornithiformes) the next successive sister, thus reversing the linear sequence proposed here.

 

By moving the Pterocliformes and Columbiformes to follow the Podicipediformes, SACC would achieve the following: (1) place them in linear sequence to reflect a monophyletic “Columbeasensu Jarvis et al., a group that also has strong support (although with the addition of Phaethontidae) in Hackett et al.; and (2) place the Columbea in linear sequence directly following the Galloanseres, in keeping with their position as sister to the rest of Neoaves (Jarvis et al. 2014), a position also consistent with that in Hackett et al., although at odds with Prum et al.

 

By moving the Cuculiformes, Caprimulgiformes and Apodiformes to follow the Columbiformes (and Columbimorphae), SACC would position these orders to: (1) reflect their sister relationship (along with the extralimital Musophagiformes and Otidiformes) with the rest of the Passerea (according to Jarvis et al 2014), and (2) reflect their position as successive sisters (although in reverse order) at or near the base of the Neoaves (as in Prum et al. 2015).

 

(g) Move the Gruiformes and Charadriiformes to precede the Eurypygiformes.

 

These are groups for which many of the phylogenies rather profoundly disagree; this motion generally follows the results of Jarvis et al. (2014) and Prum et al. (2015). Jarvis et al. (2014) placed the Charadriiformes and Gruiformes (along with the hoatzin; see below) as sisters to a clade consisting of the core waterbirds + Phaethontiformes + Eurypygiformes + the core landbirds. Prum et al. (2015) placed the Charadriiformes (along with the Phoenicopteriformes + Podicipediformes) as sister to the core waterbird clade + Phaethontiformes + Eurypygiformes, and the Gruiformes as sister to this large clade.

 

(h) Move the Opisthocomiformes to precede the Gruiformes.

 

The position of the Opisthocomiformes on the avian tree has long been unsettled. Opisthocomus has been placed near the Galliformes, Cuculiformes, Musophagiformes, Columbiformes, and other groups. Unfortunately, and perhaps unsurprisingly, recent phylogenetic and phylogenomic studies have not resolved the placement of this group. In Hackett et al. (2008), Opisthocomus was sister to a group containing the core waterbirds, Musophagiformes, Gruiformes, Cuculiformes, and Otidiformes, but bootstrap support was weak. In Jarvis et al. (2014), Opisthocomus was sister to the Gruiformes + Charadriiformes (bootstrap = 91%), and this group was sister to the core waterbirds, Phaethontiformes, Eurypygiformes, and core landbirds. In Prum et al. (2015), in contrast, Opisthocomus was sister to the landbirds, with strong bootstrap support in the published Bayesian tree but no support in the tree in the supplementary material.

 

The current SACC linear sequence places the Opisthocomiformes between the Columbiformes and Cuculiformes, breaking up groups that are either part of sister groups (Prum et al. 2015) or that form part of successive sister groups to the rest of Neoaves (Jarvis et al. 2014), and that should be placed close together in the linear sequence following either study. Placing Opisthocomus according to Prum et al. (2015) would move it to a position between the core waterbirds and core landbirds, very different from its current placement, whereas following Jarvis et al. (2014) would move it only slightly (see Appendix). I propose that the Opisthocomiformes be placed between the Apodiformes and the Gruiformes, essentially following the latter – this is something of a middle ground between the current placement and that of Prum et al. (2015).

 

Recommendation:

I strongly recommend voting in favor of some of these proposals (a-d), and I endorse the others as well. A new linear sequence that includes some or all of these changes would reflect the best data on higher-level avian relationships much better than does the current SACC sequence. The alternative would be to wait until phylogenomic studies with better taxon sampling and tree-wide consistent support are available, but consistent resolution of the initial radiation of Neoaves may be difficult to achieve, and I would say that some of these changes need to be made now.

 

If SACC approves only (a)-(d), then they would have to decide whether the remaining orders fit in their “new” positions (see the appendix below). Approval of all proposals (a)-(h) would generally follow the bulk of the phylogenetic evidence currently available. An alternative would be to follow the published tree of the most recent major study, that of Prum et al. (2015). Their published Bayesian tree received strong support at almost all nodes, but most of the deeper nodes were poorly supported in the maximum likelihood tree in their supplementary material. The differences between the (a)-(h) linear sequence and that derived from Prum et al. are in the placement of the Phoenicopteriformes + Podicipediformes (early in the a-h sequence, somewhat later in Prum et al.), the relative placement of the Pterocliformes + Columbiformes, Cuculiformes, and Caprimulgiformes + Apodiformes (in this sequence in (a)-(h), in the sequence Caprimulgiformes + Apodiformes, Cuculiformes, and Pterocliformes + Columbiformes in Prum et al.), and the placement of the Opisthocomiformes (preceding Gruiformes in (a)-(h), between the core waterbirds and core landbirds in Prum et al.). Prum et al. placed all of the “initial radiation waterbirds” together preceding the core waterbirds, and this has some intuitive appeal in that all the waterbirds are together in the linear sequence. However, the (a)-(h) sequence causes less disruption to our current linear sequence, leaving Phoenicopteriformes + Podicipediformes near the beginning of the sequence, and leaving intact the linear sequence of Columbiformes, Cuculiformes, Caprimulgiformes + Apodiformes (although in the current sequence, Opisthocomiformes and Strigiformes are embedded among these orders). To me, this seems like the slightly better course until we get more definitive data on the initial Neoavian radiation.

 

A slightly different version of this proposal (lacking discussion of Sphenisciformes and Opisthocomiformes but including discussion of Gaviiformes and Pterocliformes) formed NACC Proposal 2016-C-6.  This proposal passed unanimously.

 

Literature Cited:

Burleigh, J. G., R. T. Kimball, and E. L. Braun. 2015. Building the avian tree of life using a large-scale, sparse supermatrix. Mol. Phylogenet. Evol. 84: 53-63.

Fain, M. G., and P. Houde. 2004. Parallel radiations in the primary clades of birds. Evolution 58: 2558-2573.

Groth, J. G., and G. F. Barrowclough. 1999. Basal divergences in birds and the phylogenetic utility of the nuclear RAG-1 gene. Mol. Phylogenet. Evol. 12: 115–123.

Hackett, S. J., et al. 2008. A phylogenomic study of birds reveals their evolutionary history. Science 320: 1763-1768.

Jarvis, E. D., et al. 2014. Whole-genome analyses resolve early branches in the tree of life of modern birds. Science 346: 1320-1331.

Kimball et al. 2013. Identifying local biases in large datasets: a case study using the avian tree of life. Mol. Phylogenet. Evol. 69: 1021-1032.

McCormack et al. 2013. A phylogeny of birds based on over 1,500 loci collected by target enrichment and high-throughput sequencing. PLoS ONE 8: e54858.

Prum, R. O., et al. 2015. A comprehensive phylogeny of birds (Aves) using targeted next-generation DNA sequencing. Nature 526: 569–573.

Sibley, C. G., and J. E. Ahlquist. 1990. Phylogeny and classification of birds: a study in molecular evolution. Yale Univ. Press, New Haven, CT.

Suh, A., L. Smeds, and H. Ellegren. 2015. The dynamics of incomplete lineage sorting across the ancient adaptive radiation of Neoavian birds. PLOS Biology 13(8): e1002224, 18 pp.

 

Terry Chesser, October 2016

 

 


Appendix: The current SACC sequence of orders, the linear sequence that would result from approval of proposals a-d above, the linear sequence that would result from approval of all proposals above, and the linear sequence that would result from following the Bayesian tree in Prum et al. (2015). Orders that form part of the poorly resolved initial radiation of Neoaves are in bold, those in the core waterbird clade are highlighted in blue, and those in the core landbird clade are highlighted in green.

 


 

current sequence

 

Tinamiformes

Anseriformes

Galliformes

Podicipediformes

Phoenicopteriformes

Sphenisciformes

Procellariiformes

Phaethontiformes

Ciconiiformes

Suliformes

Pelecaniformes

Cathartiformes

Accipitriformes

Gruiformes

Eurypygiformes

Charadriiformes

Columbiformes

Opisthicomiformes Cuculiformes

Strigiformes

Caprimulgiformes

Apodiformes

Trogoniformes

Coraciiformes

Galbuliformes

Piciformes

Cariamiformes

Falconiformes

Psittaciformes

Passeriformes

 

w/ approval of a-d:

 

Tinamiformes

Anseriformes

Galliformes

Phoenicopteriformes

Podicipediformes

Eurypygiformes

Phaethontiformes

Sphenisciformes

Procellariiformes

Ciconiiformes

Suliformes

Pelecaniformes

Gruiformes

Charadriiformes

Columbiformes

Opisthocomiformes

Cuculiformes

Caprimulgiformes

Apodiformes

Cathartiformes

Accipitriformes

Strigiformes

Trogoniformes

Coraciiformes

Galbuliformes

Piciformes

Cariamiformes

Falconiformes

Psittaciformes

Passeriformes

 

w/ approval of a-h:

 

Tinamiformes

Anseriformes

Galliformes

Phoenicopteriformes

Podicipediformes

Columbiformes

Cuculiformes

Caprimulgiformes

Apodiformes

Opisthocomiformes

Gruiformes

Charadriiformes

Eurypygiformes

Phaethontiformes

Sphenisciformes

Procellariiformes

Ciconiiformes

Suliformes

Pelecaniformes

Cathartiformes

Accipitriformes

Strigiformes

Trogoniformes

Coraciiformes

Galbuliformes

Piciformes

Cariamiformes

Falconiformes

Psittaciformes

Passeriformes

 

Prum Bayesian tree:

 

Tinamiformes

Anseriformes

Galliformes

Caprimulgiformes

Apodiformes

Cuculiformes

Columbiformes

Gruiformes

Phoenicopteriformes

Podicipediformes

Charadriiformes

Eurypygiformes

Phaethontiformes

Sphenisciformes

Procellariiformes

Ciconiiformes

Suliformes

Pelecaniformes

Opisthocomiformes

Cathartiformes

Accipitriformes

Strigiformes

Trogoniformes

Coraciiformes

Galbuliformes Piciformes

Cariamiformes

Falconiformes

Psittaciformes

Passeriformes



 

========================================================

 

Comments from Remsen:  “YES to all.  I here paste in my comments from the NACC version of the proposal: The multiple independent data sets that support these groupings indicate that it’s time to start rearranging the sequence of orders to reflect these findings.  Of course future findings may cause some additional changes, but this is a good start.  Keep in mind that our current sequence is misleading with respect to all recent phylogenetic data.  Thanks to Terry for sorting this all out.  In Dickinson & Remsen (2013) we took steps in this direction and would have gone farther if we had had the most recent papers to work with.’  Reaction by some to passage of the NACC proposal, primarily those not familiar with phylogenetic data, was “how can this be?”  My response to that reaction is ….why is anyone surprised that the traditional linear sequence of orders, which has been around for a century and which is based on essentially nothing but historical momentum combined with outdated thinking in terms of evolution, is in bad need of a makeover?”

 

Comments from Stiles: “YES to all. Some of these changes are long overdue, and the rest are based upon the best evidence currently available.”

 

Comments from Pacheco: “YES for all. Currently available data justify all these adjustments in the sequence.”

 

Comments from Robbins: “YES to all proposals of rearranging the orders based on the Jarvis et al. (2014) and Prum et al. (2015) molecular data.  Yes, there is still uncertainty and there undoubtedly will be revisions, but this is a major improvement over the traditional arrangement.”

 

Comments from Zimmer: “YES to all.  Multiple independent data sets support the proposed reshuffling.  As others have noted, additional studies will probably further refine our understanding, and additional future changes are likely, but this arrangement best reflects the data that we have right now.”

 

Comments from Areta: “YES to all. There is enough evidence in these genetic studies to move the pieces around in the proposed manner.”

 

Comments from Claramunt: “YES to all subproposals. The phylogenetic positions of Strissores, Columbaves, and Podicipediformes + Phoenicopteriformes have not been resolved with confidence, and the proposed change is compatible with only some of the phylogenies out there.  However, transferring these groups near the beginning of the Neoaves sequence is an advance over our current sequence. Likewise, the ultimate position of Opisthocomus remains to be determined, but the proposed position in the sequence is at least compatible with some of the published analyses. Not sure if the uncertainties will resolved any time soon, but at list the SACC sequences would be more compatible with our current knowledge of avian phylogeny.”

 

Additional comments from Remsen: “In implementing the sequence, I noticed that following the standard convention of less-diverse first, Phoenicopteriformes should precede Podicipediformes.”

 

Comments from Stotz: “YES to all.  The genetic evidence has come together to give us a good outline of what the relationships among orders are.  We may have to do some minor rearranging in the future, as more evidence comes in, but I think evidence is sufficient that the traditional order is essentially information-free that making this enormous improvement is in order.”