Proposal (979) to South American Classification Committee

Revise the taxonomy of the Charadriidae (in 8 parts, A-H)

Background:

The Charadriidae comprises eighteen species in two subfamilies in the SACC area. Of these, ten are in the long-recognized genus of cosmopolitan Charadrius plovers. The current linear sequence (Remsen et al., 2023) for the species in this family is:

Pluvialis dominica American Golden-Plover

Pluvialis fulva Pacific Golden-Plover

Pluvialis squatarola Black-bellied Plover

Oreopholus ruficollis Tawny-throated Dotterel

Vanellus cayanus Pied Lapwing

Vanellus chilensis Southern Lapwing

Vanellus resplendens Andean Lapwing

Charadrius modestus Rufous-chested Dotterel

Charadrius vociferus Killdeer

Charadrius semipalmatus Semipalmated Plover

Charadrius melodus Piping Plover

Charadrius mongolus Lesser Sand-Plover

Charadrius wilsonia Wilson's Plover

Charadrius collaris Collared Plover

Charadrius alticola Puna Plover

Charadrius falklandicus Two-banded Plover

Charadrius nivosus Snowy Plover

Phegornis mitchellii Diademed Sandpiper-Plover

New Information:

A series of papers has come out addressing the phylogenetic relationships in the Charadriidae, with increasing amounts of data. However, all papers suffer from having few genetic markers, which hampers our ability to confidently make changes to genera, and two papers additionally suffer from limited taxon sampling. Baker et al. (2007) sampled three mitochondrial loci and one nuclear locus, targeting one sample per genus. Below is the relevant part of their tree. Note that Anarhynchus is in the same clade as Vanellus, the two of which are unrelated to the one Charadrius sample. Nodes without support values have a posterior value of 1. This study, and one a few years later (Baker et al. 2012) were the basis of SACC proposal 551, which rearranged the linear sequence of Charadriiform genera, but not genus limits.

Dos Remedios et al. (2015) sampled two mitochondrial and four nuclear loci from 29 Charadrius species. Their Bayesian consensus tree is shown below. Node values are posterior probabilities. Note a lack of any Vanellus samples, and the low node support in many parts of the tree. This phylogeny was the basis of SACC proposal 735-F, which rearranged the linear sequence of species in Charadrius but did not change genus limits. The map and colored circles are a biogeographic analysis.

Another study (Barth et al. 2013) sampled eight mitochondrial and two nuclear loci from a decent selection of Charadriidae but focusing on placing the New Zealand Dotterel (Charadrius obscurus) in the phylogeny. Their results largely corroborate those of the other papers outlined here. Their Figure 1 phylogeny is shown below. Note that nodes without circles have low support and should be considered polytomies.

Lastly, we come to the paper that is the basis for most of the changes in this proposal. Černý & Natale (2022) used a supertree approach that utilized much of the same data as in the previous papers (Baker et al. 2007, Barth et al. 2013, Dos Remedios et al. 2015), with the addition of more loci (27 total) and a matrix of 69 skeletal characters, to address the relationships of most species in the order Charadriiformes. The main issue I have with this paper is that the main figure (screenshot below) combines both the genetic and skeletal data with no indication of whether the relationships are supported by one or the other data types. I’m very skeptical of the older relationships in the main figure, given well known issues of convergence in skeletal datasets. Nodes with bootstrap support ≥70% are indicated by circles, and nodes with bootstrap support <70% are indicated by squares. As you can see, there are many squares on the nodes in this tree. This is no surprise, given the very high percentage of missing data in the molecular data matrix (68.5%!) with some samples represented by just a single locus (mean = 9.5 loci).

A portion of Figure 6 from Černý & Natale (2022), showing phylogenetic relationships in the Charadriidae. Note that the darker gray vertical lines are 10 Ma increments, and the faint gray lines are 2.5 Ma. Note that for converting this to a linear sequence, this tree should be “read” bottom-to-top.

Thankfully, the supplemental data for Černý & Natale (2022) does contain the molecular-only phylogeny, but it shows that many of the relationships, especially those deeper in the tree, are weakly supported by molecular data. To better illustrate those relationships that do have good support in the tree, I collapsed all nodes with posterior probabilities less than 0.75. Below is the relevant portion of the tree, with the species occurring in the SACC area indicated in red. Despite the weak support for many nodes, there is strong support for four main clades; 1) Pluvialis, 2) Charadrius sensu stricto, 3) Vanellus, and 4) the remainder of the Charadrius. There are a handful of species on long branches, whose relationships within the family are unresolved, including four species in the SACC area: Oreopholus ruficollis, Vanellus cayanus, Phegornis mitchellii, and Charadrius modestus. The relationship between Pluvialis and the rest of the group, and especially whether it’s closer to the Recurvirostridae, is unresolved.

As an aside, I’ve looked through the rest of this Charadriiformes tree and found just one other case of genus-level paraphyly (based on current SACC taxonomy). That topology places Sterna forsteri and S. trudeaui as sister to Thalasseus plus the rest of Sterna. However, this relationship is weakly supported, so I don’t think any changes should be considered for now.

Out of curiosity, I delved into the skeletal data used in this tree. Černý & Natale (2022) used data from Strauch (1978), which had been reanalyzed by Chu (1995). Chu (1995) presented phylogenies based solely on the skeletal data, which I’ve included below. As you can see, these deeper relationships strongly conflict with the molecular data, and as expected, place unrelated taxa close to each other in cases where morphology is similar (e.g. Vanellus closer to Recurvirostridae in some trees). Another tree from Chu (1995; not shown) with more tips and fewer markers, which includes more Charadrius tips, is less well-resolved but places Vanellus in a big polytomy with Charadrius sensu lato, so closer to where the molecular data indicate it belongs.

I think there are a few options here. One would be to wait for better data, which was my initial reaction on seeing the phylogeny of Černý & Natale (2022). However, it seems that at least WGAC and Clements are moving forward with some changes to genera, and I think it would be worthwhile for SACC to consider following these global authorities and making some of these changes. Although the molecular data are not resolving all the relationships in the group, they do indicate that our current treatment of Charadrius is highly paraphyletic, which would require a few changes. There are also a handful of species (e.g. Vanellus cayanus) that are on long branches that suggest that they could be split off as monotypic genera, even if their exact relationships are currently unresolved or poorly supported.

To make the taxonomy a bit easier to follow, I’ve listed here the author, year, and type species for each of the genera that are relevant to this matter, including those that could reasonably be resurrected for a clade. These are sorted by year.

Charadrius Linnaeus 1758, type hiaticula

Vanellus Brisson, 1760, type vanellus

Pluvialis Brisson 1760, type apricaria

Anarhynchus Quoy & Gaimard 1830, type frontalis

Eudromias Brehm 1831, type morinellus

Oreopholus, Jardine & Selby 1835, type ruficollis

Erythrogonys Gould 1838, type cinctus

Thinornis Gray, GR 1844, type novaeseelandiae

Phegornis Gray, GR 1846, type mitchellii

Ochthodromus Reichenbach 1852, type wilsonia

Zonibyx Reichenbach 1852, type modestus

Eupoda Brandt, JF 1852, type asiatica

Hoploxypterus Bonaparte 1856, type cayanus

Aegialophilus Gould 1865, type alexandrinus

Peltohyas Sharpe 1896, type australis

Afroxyechus Mathews 1913, type tricollaris

Effect on SACC area:

Following the tentative recommendations below would lead to a new taxonomic arrangement and linear sequence for the Charadriidae, as follows:

Pluvialis squatarola Black-bellied Plover

Pluvialis dominica American Golden-Plover

Pluvialis fulva Pacific Golden-Plover

Oreopholus ruficollis Tawny-throated Dotterel

Hoploxypterus cayanus Pied Lapwing

Phegornis mitchellii Diademed Sandpiper-Plover

Zonibyx modestus Rufous-chested Dotterel

Charadrius vociferus Killdeer

Charadrius semipalmatus Semipalmated Plover

Charadrius melodus Piping Plover

Vanellus chilensis Southern Lapwing

Vanellus resplendens Andean Lapwing

Anarhynchus mongolus Lesser Sand-Plover

Anarhynchus wilsonia Wilson's Plover

Anarhynchus collaris Collared Plover

Anarhynchus alticola Puna Plover

Anarhynchus falklandicus Two-banded Plover

Anarhynchus nivosus Snowy Plover

Recommendation:

Please vote on the following issues:

A. Rearrange species in the genus Pluvialis

B. Transfer Charadrius mongolus to Eupoda, and wilsonia, collaris, alticola, falklandicus, and nivosus to Ochthodromus

C. Transfer Charadrius mongolus, wilsonia, collaris, alticola, falklandicus, and nivosus to Anarhynchus

D. Adopt the new linear sequence

E. Transfer Vanellus cayanus to Hoploxypterus

F. Transfer Charadrius modestus to Zonibyx

G. Transfer Charadrius modestus to Phegornis

H. Recognize the subfamily Pluvialinae for the species in Pluvialis, and the subfamily Charadriinae for the remaining species in Charadriidae

Note that both C & D and F & G are mutually exclusive.

I recommend the following votes:

A. YES: a minor bookkeeping change, supported by the internal relationships in Pluvialis.

B. NO: despite my initial hesitation on making revisions in this group given the haphazard quality of the phylogenetic data, there is strong evidence that this clade of former Charadrius is unrelated to the core group, and is at least as divergent as genera like Vanellus, so they could potentially go in their own subfamily. Černý and Natale (2022) recommend recognizing Eupoda but not Ochthodromus, but as shown in the phylogeny of molecular-only data, there is very little support for the internal relationships in the group. However, Barth et al. (2013) do also support this topology, with a somewhat old (~17 Ma) split from the rest of this clade. I am including this one here for sake of completeness, but also because there is a possibility that if the topology in Černý and Natale (2022) holds up with better data, that it could be a viable alternative. It doesn’t matter at all for the taxonomy, but the etymology of Ochthodromus (“bank/shore-runner”) is much more appropriate for this group of plovers than is Anarhynchus (“backward-bill”).

C. YES. I highly recommend this option. The data are quite clear that this clade should not be in Charadrius and given that we don’t have a good handle on the internal topology, I think it’s safest to transfer all species to this genus for the time being. This is also taxonomy that WGAC and Clements are using, so it would put SACC in line with those global taxonomies. The one issue that I foresee here is that there could potentially be an older genus than Anarhynchus available for one of the species in this group. I did check the Richmond Index for the 28 synonyms of Charadrius listed in Birds of the World and none superseded Anarhynchus. Frank Rheindt and Pam Rasmussen have also done a thorough search for older available names (WGAC comments) and are unable to find older available names.

D. YES. Given the phylogenetic data that we have, this is the most accurate linear sequence for the group. This mostly just moves Vanellus between the two former Charadrius clades. I don’t think any changes should be made on the linear sequence within each of the groups, given the low resolution in the phylogenetic trees.

E. YES. Vanellus cayanus is on a long branch that is much older than many other groups considered genera (e.g. Vanellus sensu stricto), sister to mitchellii + modestus. The Černý & Natale (2022) phylogeny places the divergence time at about 28 Ma, which suggests genus-level divergence. For what little it’s worth, the skeletal data in Chu (1995) also place cayanus and mitchellii as sisters (modestus not included).

F. YES. Charadrius modestus is on a long branch that is much older than many other groups considered genera (e.g. Vanellus sensu stricto), and is sister to Phegornis mitchellii. The Černý & Natale (2022) phylogeny places the divergence time at about 12 Ma. Given how different these two species are, I think it’s better to keep these as separate genera.

G. NO. Just as an alternative to resurrecting Zonibyx, modestus could be transferred to Phegornis. I don’t think that this is a great option, given how distinctive these two species are, but the divergence time is slightly less than the crown age of some of the other genera in the family.

H. YES. I think it’s best to consider Pluvialis in a separate subfamily, Pluvialinae. This clade is on a very long branch and could potentially even be its own family.

Literature Cited:

Baker, A. J., Pereira, S. L., & Paton, T. A. (2007). Phylogenetic relationships and divergence times of Charadriiformes genera: Multigene evidence for the Cretaceous origin of at least 14 clades of shorebirds. Biology Letters, 3(2), 205–210. https://doi.org/10.1098/rsbl.2006.0606

Baker, A. J., Y. Yatsenko, and E. S. Tavares. 2012. Eight independent nuclear genes support monophyly of the plovers: the role of mutational variance in gene trees. Molecular Phylogenetics and Evolution 65: 631-641.

Barth, J. M. I., Matschiner, M. & Robertson, B. C. (2013). Phylogenetic position and subspecies divergence of the endangered New Zealand Dotterel (Charadrius obscurus). PLOS One, 8(10), e78068. https://doi.org/10.1371/journal.pone.0078068

Černý, D., & Natale, R. (2022). Comprehensive taxon sampling and vetted fossils help clarify the time tree of shorebirds (Aves, Charadriiformes). Molecular Phylogenetics and Evolution, 177, 107620. https://doi.org/10.1016/j.ympev.2022.107620

Chu, P. C. (1995). Phylogenetic reanalysis of Strauch's osteological data set for the Charadriiformes. The Condor, 97(1), 174–196. https://doi.org/10.2307/1368995

Dos Remedios, N., Lee, P. L. M., Burke, T., Székely, T., & Küpper, C. (2015). North or south? Phylogenetic and biogeographic origins of a globally distributed avian clade. Molecular Phylogenetics and Evolution, 89, 151–159. https://doi.org/10.1016/j.ympev.2015.04.010

Remsen, J. V., Jr., J. I. Areta, E. Bonaccorso, S. Claramunt, G. Del-Rio, A. Jaramillo, D. F. Lane, M. B. Robbins, F. G. Stiles, and K. J. Zimmer. Version 1 August 2023. A classification of the bird species of South America. Museum of Natural Science, Louisiana State University. http://www.museum.lsu.edu/~Remsen/SACCBaseline.htm

Strauch, J. G. (1978). The phylogeny of the Charadriiformes (Aves): a new estimate using the method of character compatibility analysis. The Transactions of the Zoological Society of London, 34(3), 263–345.

Oscar Johnson, August 2023

Comments from Areta: “I vote in favor of all the options recommended by Oscar (i.e., NO to B and G, and YES to the rest). I have always been in favor of Hoploxypterus, and it is also great to see Zonibyx coming back to life. These genus-level changes were recently voted on in the working list of the WGAC."

Comments from Robbins: “Oscar’s recommendations are well reasoned and given that WGAC has gone that route, makes sense to follow. I vote for all suggestions Oscar recommended.”

Comments from Zimmer: “A) YES; B) NO; C) YES; D) YES; E) YES – make that a strong YES (Placing cayanus in Vanellus always bothered me on several fronts, including structure, size, plumage, vocalizations, etc.); F) YES; G) NO – make that a strong NO (Phegornis is truly a different beast, and should be kept monotypic in my opinion.); H) YES – for all of the reasons cited by Oscar in the Proposal.”

Comments from Lane:

“A. YES.

B. NO.

C. YES. But I chuckle a little at this, as it takes a monotypic genus with the sole member, Wrybill, defined by one of the bird world's more unusual bills, and expands it to a rather speciose group!

D. YES. 

E. YES. 

F. YES.

G. NO.

H. YES.”

Comments from Remsen: “YES on all of Oscar’s recommendations. Kudos to Oscar for extracting the reliable signal out of all that messy data, and all the recommendations are cautious and wise in my opinion. That the banded plovers fall in two different genera is another example of plumage characters not necessarily providing reliable phylogenetic signal. However, that morinellus is on a long branch that argues for restoration of Eudromias is subjectively pleasing to those of us who never understood its inclusion in Charadrius. In the NACC comments, Kevin Winker made a good point on what we can/can’t make of a long branch when there are so many missing data, but I think the new data shifted the balance in what is an arbitrary decision in terms of strict typology.

“Mini-rant: That the gene-based tree was not published as a figure in the Černý-Natale paper is yet another of dozens of examples in the last decade that make me wonder sometimes if MPE is actually a peer-reviewed journal. Evidently, the message is not widely appreciated that phenotypic data have a difficult time eliminating convergence or strong divergence, as “proven” by the Livezey-Zusi monograph that produced a couple dozen conspicuous and indisputable examples of this (e.g., loons and grebes maintained as sisters, and diving-petrels and phalaropes restored to family rank). That was way back in 2007 with the world’s largest-ever matrix of phenotypic data (2K+ characters). I really like morphology and analyses of morphological data. Morphology is the phenotypic expression of all those genes on which natural selection can act. Morphological data often map well onto phylogeny but let’s see what the genes-only data look like for comparison. It’s the discrepancies that often provide insights into the process of evolution.”

Comments from Bonaccorso:

“A. NO. As far as I can see, the Černý & Natale (2022) is the only phylogeny that includes Pluvialis squatarola, dominica, and fulva, and does not have good support for the dominica + fulva relationship.

“B. NO. I might be wrong, but it seems to me that the proposal does not state clearly why this would be the best arrangement.

“C. NO, for the same reason stated in 979B.

“D. NO, as it follows from my NO on proposals A-C.

“E. NO. I understand that Hoploxypterus (Latham, 1790) would be available for cayanus but what if cayanus is also related to another species whose name could have priority over Hoploxypterus? I think it is too soon to make the change.

“F. NO. I understand that Zonibyx (Lichtenstein 1823) would be available for modestus. It could go to either Zonibyx or to Phegornis “(979G), but I think these decisions are premature given how fragmentary the phylogenetic evidence is.

“G. NO. This decision is premature given the scarcity and patchiness of the phylogenetic evidence.

“H. YES. But Oreopholus ruficollis is also in a very long branch. Should we place it in its own subfamily too?”

Response to Bonaccorso comments from Oscar Johnson: “I certainly agree that the phylogenetic data that we have available are quite poor, and that makes it a real challenge to confidently convert this to a genus-level taxonomy. I had initially advocated (to NACC) that we basically ignore the Cerny and Natale paper for the time being, given how many unresolved relationships there were in the tree, but given that at least some global checklists were moving forward with some changes, I felt it would be better to get ahead of those changes by highlighting some of the very major issues in the underlying data, with the hope that a more moderate decision by NACC or SACC might prevent a wholesale adoption of the taxonomic recommendations advocated for in these papers. I do think that some of the changes I advocate for in the proposal have reasonably good support, but I fully endorse a more moderate/conservative decision if that's how you or other committee members choose to proceed. Below are some more details on each of the sub-proposals:

“A) The linear sequence rearrangement I presented for Pluvialis moves squatarola to the beginning of the genus, which is supported in Cerny and Natale (2020) by a 100% bootstrap support on the branch leading to squatarola, but does not change the order of dominica vs fulva due to the poor resolution in this part of the tree.

“B/C) The phylogenetic data in Cerny and Natale (2020) and prior papers (especially Barth et al. 2013) all support this clade of former Charadrius being more closely related to Vanellus than to Charadrius sensu stricto, thus rendering Charadrius paraphyletic and requiring a change in genus limits if the phylogenetic data are to be trusted. I certainly understand wanting to wait for better data given that these papers are all based on relatively few loci, but the bulk of the evidence (to me) point towards paraphyly in Charadrius. I gave these two sub-proposals as competing options on how to circumscribe the genus limits in this clade of former Charadrius, with the recommendation of adopting the minimal number of new genera (Yes on C). A Yes on B would take this clade of former Charadrius and adopt three new genera: Anarhynchus, Eupoda, and Ochthodromus, which was what was advocated for by Cerny and Natale, but as is clear from the molecular-only phylogeny in that paper, the relationships within this clade are largely unresolved, so I recommended instead transferring all of these species to Anarhynchus (Yes on C) and awaiting better phylogenetic data before further splitting the genus.

“D) Other than re-arranging the position of the newly circumscribed genera that I advocate for in the sub-proposals, I did not change the linear sequence within any genera due to the largely unresolved phylogenetic data. I could easily have made a mistake here, so it's worth double-checking my work. Also, if some of the genus limits I recommend are not adopted, then this linear sequence would need to be revised.

“E/F/G) These (potentially) monotypic genera are certainly the toughest part of these sub-proposals, which is why I gave each one as a separate voting option in case the committee wanted to accept/reject each one individually. It's certainly possible that Vanellus/Hoploxypterus cayanus is related to another clade, but aside from Vanellus there's no other clade that it would be clearly allied to in terms of morphology. In other words, even if it is sister to another genus on a long branch, I'm not sure it would make sense to merge it with that other genus based on its different morphology. Leaving it in Vanellus would certainly be a valid option for the time being. For modestus, I really don't know what the best solution is here, which is why I gave two competing options. The phylogenetic data does seem to support it being sister to mitchellii, however, rather than part of Charadrius.

“H) It's certainly possible that Oreopholus is on a long-enough branch to be its own subfamily, but the phylogenetic data (such as it is) does indicate that it's in a polytomy at the base of the rest of Charadriinae, so this seems like it would be premature. Pluvialis, on the other hand, is in a polytomy at the base of the node uniting not only the rest of Charadriidae, but also Recurvirostridae and Haematopodidae, so moving it to its own subfamily seems to me to be the more conservative option (versus its own family).

Additional comments from Bonaccorso: “I vote in favor of all the options supported by Oscar (NO to B and G, and YES to the rest). I am a little worried that some unexpected relationships arise when better taxonomic sampling and better phylogenetic data but, for the time being, they all seem to make sense.”

Comments from Claramunt: “I largely agree with Oscar’s assessment and recommendations except for a few points. There is nothing haphazard in Černý & Natale dataset: it is a supermatrix approach (not a supertree approach) based on all GenBank sequences. Many species indeed lack data for many loci but the methods they used are robust to missing data. The main problem is the low statistical support for many clades.

“A. YES to rearrange species in the genus Pluvialis

“B. YES to transfer wilsonia, collaris, alticola, falklandicus, and nivosus to Ochthodromus. In this one, I disagree with the recommendation, which is based on a conservative approach due to low support for the relevant nodes. My point is that despite low support, the published evidence points to the separation of this clade into three groups: Eupoda, Anarhynchus, and Ochthodromus—and that classification is better, in my opinion, than one with an Anarhynchus including most species. First, is the issue of the meaning of the name, mentioned by Oscar; if possible, we want names that make sense; there is nothing awkward with the beak of all Ochthodromus species. But an additional argument is the minimization of drastic changes in the meaning of the genera. Anarhynchus was a monotypic genus restricted to New Zealand. Proposal C would transform it into a species-rich cosmopolitan genus. This can be avoided by resurrecting Ochthodromus. Anarhynchus may contain more than one species but will still be endemic to Australasia.

“C. NO to Transfer Charadrius mongolus, wilsonia, collaris, alticola, falklandicus, and nivosus to Anarhynchus, for the reasons explained above.

“D. YES to adopt the new linear sequence

“E. YES to transfer V. cayanus to Hoploxypterus

“F. YES to transfer C. modestus to Zonibyx

“G. NO to transfer C. modestus to Phegornis. As much as I am averse to monotypic genera, modestus and mitchellii are very divergent temporally and phenotypically.

“H. YES to recognize the subfamilies Pluvialinae and Charadriinae.”

Comments from Stiles: “Given that the clades of small “ex Charadrius” represent a massive polytomy, of the two competing options (B and C) I agree with Santiago that B better expresses the nomenclatural situation: the generic name Ochthodromus fits as a widely distributed and relatively homogeneous group (and its English name also fits nicely; whereas Anarhynchus was named for a definite oddball bill of its type, and its two congeners are also with restricted Australasian distributions. I therefore favor B, for separating mongolus to Eupoda, maintaining a broad Ochthodromus, which in turn would produce a narrow, separate Anarhynchus. Conversely, a NO to C (subsuming Ochthodromus into Anarhynchus), which clashes with my preconceived notion of what a genus should represent. To sum up my votes on this one, NO to C and G, Yes to all the other propositions."

Additional comments from Oscar Johnson: “Since the writing of SACC proposal #979, an additional paper has been published on the phylogenetics of the Charadriiformes that provides additional resolution, in particular, to part of the tree relevant to the genus limits of the Charadriidae. Dufour et al. (2024) used much of the same GenBank DNA data as in Černý and Natale (2022), but with improved sequence alignment and quality control methods that improved the final tree. Below I have included the relevant portion of the tree of Dufour et al. (2024) showing the phylogeny of the Charadriidae. This tree is time calibrated based on fossil data, and the vertical axis marks are in 5 Ma increments.

“Most notable from this phylogeny is the confirmation (based on this set of DNA markers) of the monophyly of the ‘Ochthodromus’ clade being separate from the former Charadrius (=Anarhynchus). This Ochthodromus clade had a 0.97 posterior probability, and in light of this (and comments by two SACC members on the original proposal), I now recommend that this clade be transferred to Ochthodromus instead of Anarhynchus.

“Unfortunately, the resolution of “Eupoda” versus Anarhynchus still has very poor node support (0.45 posterior probability) and should be considered a polytomy. In light of this, I still recommend that the “Eupoda” Sand-Plovers be transferred to Anarhynchus instead of their own genus.

“Many of the other changes recommended in the original proposal are upheld by this updated dataset, although cayanus and ruficollis are still on long branches with poor support. The division of Thinornis from the remaining Charadrius is also supported but all the species that would be in Thinornis are extralimital.

“Dufour, P., P.-A. Crochet, F. L. Condamine, and S. Lavergne. 2024. Seasonal migration and the evolution of an inverse latitudinal diversity gradient in shorebirds. Global Ecology and Biogeography e13817. DOI: 10.1111/geb.13817”

Comments from Leo Joseph (voting for Del-Rio):

“A. Rearrange species in the genus Pluvialis: YES.

“B. Transfer Charadrius mongolus to Eupoda, and wilsonia, collaris, alticola, falklandicus, and nivosus to Ochthodromus: NO.  It's not that these shifts are totally unarguable and totally indefensible, but one can counter, I think, that the molecular support for robust structure, especially that for separating Eupoda, isn’t there. True, it looks to be there in papers such as Barth et al. until you dig deeper. Driving my caution here is that I have learned the hard way that a clear mtDNA result can drive and override the almost meaningless data from nuclear genes that often do little more than offer a defence for saying, "Well, we haven't looked just at mtDNA." When I dug into Barth et al.'s main paper and supplementary data, I saw that they had one intron as the nuclear gene in their analyses and some very poor support for structure in the whole group. So, despite what the mtDNA might be saying (and remember they were focused on the position of one NZ taxon), I guess I'd prefer to have the starting point of clear, robustly supported  structure across the group and then to recognize genera.

“C.  Transfer Charadrius mongolus, wilsonia, collaris, alticola, falklandicus, and nivosus to Anarhynchus: YES. For all the same reasons as just outlined in suggesting NO, to Point B. And yes it is a laugh that the oldest genus-group name should belong to an obscure little NZ species with a weird bill, but it seems that that is the case. In some ways, that might be a telling point here because the entire group looks like a radiation of very closely related things with some interesting evolution in bill morphology and body size perhaps reflecting dietary/niche partitioning out on the world's mudflats, coupled with an evolutionary shuffling and reshuffling of a limited number of ancestral plumage traits (coloured chest bands and frontal bands for example). Beware the nomenclaturalists of the world who may find an older name than Anarhynchus out there. It does seem weird that a New Zealand bird should have an older generic name than all of the others but maybe not if they were all just unquestioningly placed in Charadrius.

“D. Adopt the new linear sequence: YES

“E. Transfer Vanellus cayanus to Hoploxypterus: YES. Crazy bird in every way! Has always made me think of Elseyornis on Strontium 90.

“F. Transfer Charadrius modestus to Zonibyx: YES.

“G. Transfer Charadrius modestus to Phegornis. NO!

“H. Recognize the subfamily Pluvialinae for the species in Pluvialis, and the subfamily Charadriinae for the remaining species in Charadriidae. YES.”