AOU Committee on Classification and Nomenclature (North & Middle America)
Comments on Proposals 2016-B
2016-B-1a: Move Purple Swamphen Porphyrio porphyrio from the Appendix to the Main List
2016-B-1b: Split P. porphyrio into six species, thereby removing P. porphyrio from the Main List and adding Gray-headed Swamphen P. poliocephalus
2016-B-1c: Add African Swamphen P. [porphyrio] madagascarensis to the Main List.
2016-B-2: Revise the subfamilies of Scolopacidae: (a) Eliminate Phalaropodinae, and (b) Restructure the family into five subfamilies
2016-B-3: Split Emerald Toucanet Aulacorhynchus prasinus into seven species
2016-B-4: Transfer Yellow-breasted Crake Porzana flaviventer to Hapalocrex, and transfer Laysan Rail P. palmeri and Hawaiian Rail P. sandwichensis to Zapornia
2016-B-5: Recognize new subfamilies of tanagers
2016-B-6: Split Costa Rican Warbler Basileuterus melanotis and Tacarcuna Warbler B. tacarcunae from Three-striped Warbler B. tristriatus
2016-B-7: Transfer White-thighed Swallow Neochelidon tibialis and Black-capped Swallow Notiochelidon pileata to Atticora
2016-B-8: Revise the generic classification of 3 species of Hylophilus: (a) Resurrect Pachysylvia and (b) Recognize Tunchiornis (SACC 656-A, -B)
2016-B-9: Revise the linear sequence of Vireonidae (SACC # 661)
2016-B-10: Revise the classification of the Apodiformes
2016-B-11: Recognize Psittacara maugei as a separate species from Hispaniolan Parakeet P. chloropterus
2016-B-12: Split Sirystes albogriseus from S. sibilator (SACC # 610-A)
Move Purple Swamphen Porphyrio porphyrio from the Appendix to the Main List
YES - 6 without comment.
YES. The evidence is clear.
YES. The species is certainly established in Florida and has been added recently to the ABA list of North American species as an introduced species.
YES. Dispersing swamphens (a pair present for three months) have been recently found in Alachua County, pushing their distribution to the north portion of the Florida Peninsula.
YES. Evidence is overwhelming that the species is established.
Split P. porphyrio into six species, thereby removing P. porphyrio from the Main List and adding Gray-headed Swamphen P. poliocephalus
YES - 2 without comment.
YES. I agree that the morphological and genetic divergence argue for species status for poliocephalus.
YES. Although I don’t think that the case for a six-species treatment as such has been well-justified in print, the case for multiple species is difficult to deny, especially now that Garcia-R and Trewick (2015) have demonstrated that sympatric Notornis is embedded within Porphyrio porphyrio s.l. When Rasmussen and Anderton (2005) noted the differences in morphology and vocalizations, and that Porphyrio porphyrio s.l. had been treated as multiple species in Peters (1934), it was still not clear whether, in the event of a split, the morphologically dissimilar but geographically adjacent poliocephalus and indicus should be considered conspecific. Now, Garcia-R and Trewick’s (2015) phylogeny suggests that they aren’t even sister taxa, with indicus genetically close to nominate porphyrio. Fortunately, even if we remain agnostic on exactly how many species are involved, we can safely elevate poliocephalus (the form to which the Florida population obviously pertains) to species status without it being likely that we will have to change it yet again soon, because the name poliocephalus is the oldest name for any taxon in that portion of Garcia-R and Trewick’s (2015) tree.
NO. It's likely that P. porphyrio should be split, but I don't think the evidence is compelling enough for us to make the call on how to treat these taxa.
No. We should be followers, not leaders, in this split of extralimital taxa and there is enough uncertainty here that the outcome is not clear.
NO. As for the six way split, there is an earlier useful reference that outlines the issue and also splits up the species (Sangster, G. 1998. Trends in Systematics. Purple Swamp-hen is a complex of species. Dutch Birding 20:13-22). Sangster (1998) recognizes six species, two of those occur in southeast Asia: Grey-headed Swamp-hen (P. poliocephalus) and Black-backed Swamphen (P. viridis), a split followed by Craig Robson in the latest version of South-East Asia field guide (2011). But, at least in Thailand there is a good deal of skepticism about the split of those two with lots of intermediate birds being seen and the plumages not matching birds seen from the range of one or the other. Philip Round and Wichynan (Jay) Patthanakij are not going to follow this split when they soon publish the latest edition of the Thai checklist. I don’t doubt that there may be multiple species in this complex, the populations from much of Africa (madagascariensis) and themadagascariensis group from Australia, New Zealand, Micronesia, eastern Indonesia, etc. perhaps being the most distinct (from others), but from what I have read the basis for the split is based entirely on molecular work and the morphology. Regarding the morphology, at least from mainland Asia, it’s a complex web involving individual variation (and morphs) as well as a general cline of declining size from west to east. What’s missing from any study is any analysis of vocalizations which is obviously important for speciation, especially within this order, and one of the key determiners that was considered in the split of the New World Common Gallinule from the Old World Common Moorhen and just recently with the Gray-necked Wood-Rails. My personal experience with the species (and all auditory encounters) comes from Thailand. The calls from these gray-headed birds are long and involved and quite frankly sound like one being tortured. Calls should be played regularly over the loudspeakers to the inmates at Guantanamo. No further “enhancement” techniques would be needed for their “cooperation.” Seriously, if there are really six species involved, there must be differences between them! As I understand this, the split seems largely to be a PSC split.
NO. That paper, while pretty good, does an inadequate job of determining species limits in the group. I don’t find the evidence there compelling to recognize six species. P. porphyrio should probably be split, but evidence doesn’t seem strong there to declare that six is right.
NO. I suspect we will eventually split up this species but, maybe not into 6, and this doesn’t really provide any data that supports species status for any of the subunits.
NO. The rationale for the split is that P. mantelli/hochstetteri (takahes), treated as separate species by any criteria, are embedded within the tree of relationships among P. porphyrio subspecies. I have two problems with the paper’s rationale:
1. No mention of potential gene tree vs. species trees beyond pointing out that there was no "significant conflict" among the three gene trees. The phylogeny presented is based on the concatenated sequences of 2 mitochondrial and 1 nuclear gene. All in all, not an impressive data set by current standards, and perhaps insufficient to eliminate the possibility of a gene tree/species tree problem. I’m baffled by the seeming continued imperviousness of ornithology to this species tree/gene tree problem. Exposed in Drosophila as long ago as 1983, and dramatized by the initial shocker that Polar Bear made Brown Bear a paraphyletic species (until additional loci sampled – see most recently Cronin et al. 2014 J. Heredity), it’s time to scrutinize carefully any assessment of species limits based on a small number of loci.
2. Even if the gene trees do represent true species relationships, thus making broadly defined P. porphyrio a paraphyletic species, this does not bother me. In fact, depending on what gene trees one looks at, many widespread species are paraphyletic taxa – see Omland & Funk paper (ARES 2003). The criterion of monophyly is of course sine qua non for taxa above the species level, but expecting dichotomous branching in divergence at the population level is naïve. Peripheral speciation involving polytypic source populations leaves the original species paraphyletic with respect to the peripheral isolate. Island derivatives such as the takahes naturally differentiate rapidly from the ancestral stock. In my opinion, the criterion of monophyly is difficult to apply at the species level in general, but especially with respect to peripheral speciation.
That said, broadly defined P. porphyrio may contain multiple species-level taxa, but until actual data are presented that address directly that issue, I think we should hold off. If other classifications elevate the various P. porphyrio subspecies to species rank based on data like these, then that reflects poorly on them.
Add African Swamphen P. [porphyrio] madagascarensis to the Main List.
YES (option 3) - 4 without comment.
YES (option 3, assuming no split in 2016-B-2). If there is a split, then option 1.
YES (option 3). The Delaware record happened slightly before birds were noted in Florida, but perhaps the Florida birds were present earlier and in any event the Delaware bird was gray headed from the Central/East Asian group. It seems pretty problematical to me that it represents a wild bird. This view is reinforced after perusing European literature (e.g. Cramp, Beaman and Madge, etc.) where central and northern European records are questioned on origin. I’m not sure the basis for that, and am not even sure what subspecies group these "records" come from, but without further investigation, it would seem foolish to accept the Delaware bird when more proximal records from Europe are not accepted. And, in any event the Delaware record did not represent one of the most proximal subspecies groups. The 2009 Bermuda bird [nice color photo published in the Bermuda Audubon Society Newsletter, Vol 20 (2)] does represent one of the two most proximal subspecies. I also agree that records from this order represent one of the most dispersive groups around and the burden of proof should be on those to indicate why a record should be questioned. Bermuda has a long list of extraordinary records from all parts of the globe. This is not surprising given the location, the small size, and the coverage. Islands from the eastern Atlantic, notably the Azores are rapidly compiling a huge list of vagrants (mostly from North America, but records of species from central Asia too). Yes, the record could have been a ship assist, but the species would seem to have the capability of reaching Bermuda on its own. Some common sense has to be used, of course. For instance a Sheathbill recorded on the south coast of England shortly after the British fleet had returned from the Falklands War was almost certainly a ship assist, and the species has no place on the main list of British Birds (Category A). A group of Laysan Albatrosses that sat on the deck of a container ship as it rode to port in Oakland (Alameda County), CA should not be added to the Alameda County list.
YES (option 3: no split, but accept as wild vagrant). Rails will be rails, and the genus Porphyrio contains some of the champion vagrants on the planet. Unless there is compelling evidence that the bird was involuntarily transported, then it should stand as "innocent until proven guilty." The "issue" of ship-assistance is not an issue. I think we should adopt the sensible ABA policy. Vast numbers of migrants are "ship-assisted" every year with ships providing resting places for various amounts of time and thus transporting the birds varying distances and in many cases allowing them to survive. A good percentage of land bird vagrants to all islands likely were ship-assisted to some degree. There is no way to distinguish between those that did and did not use ships or for that matter, flotsam, natural or artificial.
Revise the subfamilies of Scolopacidae: (a) Eliminate Phalaropodinae, and (b) Restructure the family into five subfamilies
YES to both parts - 3 without comment.
YES to both parts. This makes good sense to me.
YES. All recent data support this classification. In the spirit of simplifying English names for higher taxa, I suggest changing "Subfamily Tringinae: Tringine sandpipers and phalaropes" to just "Tringines." Phalaropes aren;t even a tribe, and only a few species in the family are called "Sandpiper” so why not just got with Tringines (which besides sandpipers and phalaropes includes tattlers, yellowlegs, willet, and shanks).
YES to both parts, and no objections to "Tringines." I suggest Scolopacidae = Sandpipers and Allies.
YES to both parts. These seem to be robust clades. Yes to "Tringines" and "Sandpipers" ("and allies" does sound dated and doesn't add much).
YES to both parts. Yes to "Tringines" and "Sandpipers" (although I also find "and allies" fine too).
YES to both parts, and to suggested English names for Tringinae and Scolopacidae.
YES to both parts. Very good evidence that Phalaropus is close to the shanks (with Xenus). The genetic evidence seems pretty strong that these five subfamilies represent well supported clades. I see that Cracraft (in Dickinson and Remsen 2013) used these subfamily names previously, so I guess they are available.
Split Emerald Toucanet Aulacorhynchus prasinus into seven species
YES - 2 without comment.
NO. The proposal points out interesting geographic variation in this complex but does not provide a convincing argument for reproductive isolation that would support such a split.
NO. There could well be more than one species involved, but I prefer to await see analysis of vocal data.
NO, pending additional studies of characters other than mtDNA.
NO. Surprisingly, there is no critical examination of species limits in this proposal. Evidence of hybridization and highly similar vocalizations have been given as evidence for subspecies-level taxa, yet these are not mentioned. The sampling in the genetics studies do not adequately address population-scale questions.
NO, although I would like to vote YES only to splitting Emerald Toucanet into three species in the NACC area (it doesn’t look like the issue has been dealt with by SACC yet). The Puebla-Olivares et al. (2008) paper seems to show that NACC-area toucanets are comprised of four fairly deeply diverged lineages. As the proposal states, the Bonaccorso et al. (2011) paper shows the same pattern but does not include cognatus of Darien, which is represented in the Puebla-Olivares et al. (2008) paper by one specimen. It seems that more data are needed to establish whether cognatus really is that divergent from caeruleogularis genetically; it isn’t obviously especially different morphologically. These four taxa all have broadly similar vocalizations but they do have slight but seemingly consistent differences in note length and tone, at least between prasinus, wagleri, and caeruleogularis; I’m not so sure about cognatus based on just two recordings on XC. Again, it seems it would be better to await further data and analysis before determining whether cognatus should be considered a separate species.
NO. The various subspecies in broadly defined A. prasinus are divergent in terms of coloration and thus it is expected that they are also divergent to some degree at neutral loci. Whether these data should result in a change in taxonomic rank of the various allopatric populations, however, is highly problematic. Color differences in parapatric toucans are not associated with barriers to gene flow! Despite major differences in coloration among subspecies of Ramphastos toucans in Amazonia, they intergrade freely wherever in contact (see various Haffer papers). In contrast, syntopic species of Ramphastos show parallel plumage to the point that they are more similar to each other than they are to subspecies within their respective species (e.g., Haffer and Weckstein papers). Taxa treated as subspecies in the Pteroglossus torquatus complex that differ strongly in plumage (and treated as species in some classifications. e.g. "Stripe-billed Araçari") intergrade at their contact zone in the Chocó (Haffer 1974). In Pteroglossus flavirostris, the subspecies mariae was formerly considered a separate species ("Brown-mandibled Araçari"), but Haffer (1974) showed that they freely interbreed wherever in contact. Within Aulacorhynchus itself, Schwartz (1972) found that the taxon calorhynchus, previously treated as a species ("Yellow-billed Toucanet"), forms a zone of intergradation at its contact zone with sulcatus despite strong differences in bill color. Within the A. prasinus complex, Short & Horne (2001) pointed out that the taxa known to intergrade are just as distinctive in coloration as the allopatric taxa proposed as species in this proposal.
In contrast to plumage, vocal differences correlate strongly with lack of free interbreeding in toucans (Haffer 1974). Donegan et al. (2015, Conservación Colombiana) provided a nice summary of species limits with respect to vocal differences in toucans occurring in Colombia. The bottomline is that in this family, strong color differences are irrelevant to reproductive isolation, whereas vocal differences are excellent (perfect?) indicators of absence of free gene flow. Therefore, until the vocalizations of these allopatric taxa are studied and analyzed, any change in taxon rank based solely on plumage differences is premature.
More broadly, genetic differences in neutral loci among allopatric taxa are expected, especially if there are known coloration differences. Those differences span nearly an order of magnitude in terms of % sequence divergence, and there is no way to arbitrarily assign taxon rank based on genetic distance.
A waffly NO. The proposal is rather simple and does not elucidate why these taxa would be reproductively isolated. I agree that the morphological divergence is substantial, and because toucans (e.g., Ramphastos) can be reproductively isolated with fairly minor plumage/bare part differences, which is not brought up in the proposal, giving these taxa species rank seems okay. Bill colors and throat color seem to be important for species differentiation in this group. Nonetheless, at no point are any of the taxa sympatric and the proposal does not mention vocalizations at all, even though vocalizations are the main means by which very similar species of sympatric toucans differ (e.g., Ramphastos). I listened to all relevant taxa on xeno-canto and the prasinus complex has a number of different types of vocalizations. The long calls (nasal series of "yack" notes) seem pretty similar among the taxa of concern to the NACC. An in-depth analysis is needed. I could be persuaded to go either way.
The suggested English names need work. Here is a suggestion:
prasinus: Northern Toucanet
wagleri: West Mexican Toucanet
caeruleogularis: Blue-throated Toucanet
cognatus (if split): Darien Toucanet
NO - Other comments explain it pretty well.
Transfer Yellow-breasted Crake Porzana flaviventer to Hapalocrex, and transfer Laysan Rail P. palmeri and Hawaiian Rail P. sandwichensis to Zapornia
YES - 5 without comment.
YES to both. Given its peculiar morphology (and skeleton), it is not surprising that flaviventer is not related to Porzana (s.s.). Given the biogeography, I am not surprised that the Pacific radiation (Zapornia) is not related as well.
YES. Seems straightforward and necessary.
YES to all three (two transfers and a change in sequence).
YES. Porzana is clearly polyphyletic, and so the only question is to which genera should the non-Porzana taxa be allocated.
YES. However, the basis for using Hapalocrex rather than Poliolimnas is not even mentioned in this proposal. It is in a different but related proposal from SACC (SACC # 652).
Recognize new subfamilies of tanagers
YES - 5 without comment.
YES. Should be uncontroversial. Makes our taxonomy more phylogenetically useful.
YES. These groups are defined on the basis of a robust molecular phylogeny.
YES. I think we clearly need to provide some structuring to this large and heterogeneous family.
YES. Tanagers are currently the largest family of songbirds (about 370 species) and the second largest family of birds (only surpassed by Tyrannidae). As such, there is a lot of diversity that needs some organization. This proposal does what I think a good classification should do. That is, help organize that diversity so the group can be properly studied. For too long, we didn’t know what a tanager was and, because of that, their classification was a mess. Furthermore, I would argue that the lack of a classification has also hindered their study in other ways. Now we finally have a robust phylogeny for the group and can even place names to subgroups that share history and molecular, morphological, behavioral, and ecological similarities.
I agree that, as currently applied, Linnean ranks do not share equivalency across all of life in terms of age, number of species, or degree of morphological or genetic divergence. Pursuing a temporal banding (Avise & Johns 1999) approach, with nodes applied to ages is one approach and would capture one element often proposed to make Linnean ranks more standardized. We are probably at the point now where we could pursue/propose this across all birds, and I think that a comprehensive classification could be put forth if people want to argue that time is the most important element of a Linnean rank. In fact, this was done by Holt & Jonsson (2014) using the Jetz tree (in that classification, the family that includes tanagers has 1,418 species in it!).
In any event, I don’t think we should apply the temporal approach piecemeal to particular lineages in our classification. If this standard is applied to tanagers and this proposal doesn’t pass, their classification will continue to languish. Bottom line, I think there is more to gain than to lose by recognizing these as subfamilies. I argue for moving forward with recognizing these as clades at the subfamily level. Later, if we want to adjust multiple family/subfamily ranks within Passeriformes simultaneously, this could be done more comprehensively.
A weak NO. I may be off base here, but are these subfamily level taxa simply the result of the fact that we presently have the whole group named as a family? Given rapid radiation, might not the whole group instead represent a subfamily, more commensurate with subfamily-level divisions among, e.g., non-passerines? I guess my concern is that we are in danger here of having very unequivalent subfamilies in terms of age. I am not opposed to naming these clades, just that calling them subfamilies seems to be expanding that category to a younger set of taxa than I am comfortable with at present. This is a wider problem than this proposal, so I do not look for an answer here, but it is something we should probably discuss more outside of the individual proposal framework.
Split Costa Rican Warbler Basileuterus melanotis and Tacarcuna Warbler B. tacarcunae from Three-striped Warbler B. tristriatus
YES - 5 without comment.
YES to both. This another tough decision, without much data or comparisons to assess if the taxa are or are potentially reproductively isolated. The position of melanotis in the clade (basal to all other tristriatus + trifasciatus) and the vocal differences argue well for species status. Whether to afford species status to tacarcunae is less clear. The vocal evidence is equivocal as there is only one sample. The genetic data shows that it is well separated, from other taxa, but its position is not well supported, and mtDNA trees can be misleading. Donegan only had one specimen it appears to assess morphology as well. The photo of tacarcunae provided in Donegan however, looks quite different than neighboring taxa. Again, I feel that the total evidence presented argues for giving tacarcunae species status. Both Darien and Talamanca areas are well-known for having endemic highland species.
YES. This is a well-reasoned split based on multiple lines of evidence.
YES to both. Although melanotis is a clearer-cut case for a split than tacarcunae, it seems unlikely that the position of the latter would change so significantly in another analysis that this would not be warranted.
YES. My vote is based on the vocal data and not on the mtDNA gene tree, which I would consider nearly irrelevant to taxon rank in this group.
YES. Well-written proposal.
Transfer White-thighed Swallow Neochelidon tibialis and Black-capped Swallow Notiochelidon pileata to Atticora
YES - 8 without comment.
YES. Uncontroversial, as the resolution of the tree is fine.
YES. This solution is well supported.
Revise the generic classification of 3 species of Hylophilus: (a) Resurrect Pachysylvia and (b) Recognize Tunchiornis (SACC 656-A, -B)
YES to both parts - 8 without comment.
YES to both parts. The Vireonidae will still need some work, but the resolution of some basal nodes are not well resolved in the Slager et al. study. It seems likely that the genus Vireo will need to be split (spectacled + eyering clades = Vireo; gilvus + olivaeus clades = Vireosylva; and seprate genus for hypochryseus).
YES, but weakly. This is okay as far as it goes, but I do not like a piecemeal solution ignoring the generic limits of Vireo; I would much prefer a holistic solution to both genera so we can see a clean resolution to this taxonomic mess.
YES- 9 without comment.
YES with some tweaking, if we want to follow the well resolved parts of Slager et al. In the eye-ring clade, a well resolved node includes seven species (griseus, crassirostris, pallens, bairdi, caribaeus modestus, and gundlachii) and thus should be at the end of that clade, but the order, according to our conventions on the phylogram and geography should be pallens, bairdii, griseus, crassirostris, gundlachii, modestus, caribaeus. The only other well resolved node in that clade includes three species (brevipennis and atricapilla, along with nelsoni), so I would put this before those seven. I would list the other four (bellii, modestus, nanus, latimeri) in geographic order. In the "olivaceus" clade, flavoviridis is basal to the others with good support, thus it should be first.
Vireo nelsoni *
Vireo gundlachii *
Vireo caribaeus *
Revise the classification of the Apodiformes
YES - 3 without comment.
YES. But this is a judgment call and not especially compelling.
NO - 4 without comment.
NO. The data that led to the splintering of Caprimulgiformes confirms that swifts and hummingbirds form a monophyletic clade, as already represented by their inclusion in the order Apodiformes. I prefer to retain that bit of information by maintaining the status quo rather than split them, which will suggest to people that they do not form the long recognized monophyletic clade.
NO. Although it would be nice to be able to draw vertical lines through trees and base our higher-order classification on that, I think that it still is too messy with regards to the markers and tree-building algorithms used. On top of that we would "lose" the phylogenetic information that swifts and hummingbirds are sister taxa. Or that is how most would view it.
NO. In the other cases in which we elevated a family, this was necessitated either by a combination of paraphyly and age (former Caprimulgiformes) or simply age (Cathartiformes). Elevating the Trochiliformes is necessitated by neither: they are sister to the Apodidae and can remain in the Apodiformes, and they are much younger than almost all of what we consider orders according to the tree in Jarvis et al. 2014 (see attached) – only Piciformes/Coraciiformes are even in the same ballpark. If we use the Paleocene or Paleocene/early Eocene (54 mya) cutoff discussed in proposals on the ex-Caprimulgiformes and Cathartiformes, the Trochiliformes either fall short or are borderline in the Prum et al. 2015 tree as well (see Proposal C-9 on Cathartiformes for the tree). In my view, it’s fine to elevate families that are clearly beyond the usual family/order threshold, but elevating borderline orders should really only be done if we’re going to reconsider all orders or potential orders. We don’t know how many of the orders in Jarvis et al., when sampled for more than 1 species, would be as old or older than the hummingbirds/swifts. Further, as pointed out by Doug and Andy, by splitting we would lose the phylogenetic information that swifts and hummingbirds are sister taxa and might even suggest to people that they do not form the long recognized monophyletic clade.
Recognize Psittacara maugei as a separate species from Hispaniolan Parakeet P. chloropterus
YES - 4 without comment.
YES. The evidence is strong. I like Puerto Rican Parakeet.
Winker: YES. Enjoyed Olson’s paper.
YES. The plumage and morphological differences are as great or greater than between other species in the genus Aratinga (sl). I agree that Puerto Rican Parrot is the appropriate English name.
YES. Seems like this is about a century overdue.
YES. Prefer Puerto Rican Parrot.
YES. The case is clear-cut. The English name Puerto Rican Parakeet could easily be confounded with Puerto Rican Parrot, although the use of e.g. Hispaniolan Parakeet and Hispaniolan Parrot doesn’t seem to be a problem.
YES - 5 without comment.
YES. The evidence (especially vocal data) is strong, and we should do this for consistency with the SACC. I am fine with Choco Sirystes.
YES. Choco Sirystes for the English name of the one occurring in our area in Panama.
YES. The vocal differences alone would convince me, but the morphological differences are also certainly on par with differences that we find among Myiarchus taxa that we call species. Choco Syristes is a good English name.
YES, both to the split and to using the name Choco Sirystes.
YES. Song and plumage do support this split.