From ScienceDaily:
New research by the Milner Centre for Evolution academics in collaboration with Sun Yat-sen University in Guangzhou (China) shows that Southern and Northern breeding populations of plovers in China are in fact two distinct species: Kentish plover (Charadrius alexandrinus) in the North and white-faced plover (Charadrius dealbatus) in the South.
Using state-of-the-art genomics analysis, the team revealed that the Kentish plover and white-faced plover diverged approximately half a million years ago due to cycling sea level changes between the Eastern and Southern China Sea causing intermittent isolation of the two regional populations.
The results show that despite looking very similar, the two plover species have high levels of genetic divergence on their sex chromosomes, (Z chromosome) than on other chromosomes, indicating that sexual selection might play a role to in the evolution of the two species.
Dr Yang Liu, a visiting scholar from Sun Yat-sen University at the Milner Centre for Evolution, led the work. He said: “The initial divergence of the two plovers was probably triggered by the geographical isolation.
“However, other factors, such as ecological specialisations, behavioural divergence, and sexual selection could also contribute to the speciation of the two species. Paper. (open access) – Xuejing Wang, Kathryn H. Maher, Nan Zhang, Pinjia Que, Chenqing Zheng, Simin Liu, Biao Wang, Qin Huang, De Chen, Xu Yang, Zhengwang Zhang, Tamás Székely, Araxi O. Urrutia, Yang Liu. Demographic Histories and Genome-Wide Patterns of Divergence in Incipient Species of Shorebirds. Frontiers in Genetics, 2019; 10 DOI: 10.3389/fgene.2019.00919 More.
So different sets of genes can result in identical looking birds? This is getting as complicated as the butterflies.
From Jonathan Martinez at Eurekalert:

See also: A physicist looks at biology’s problem of “speciation” in humans
That’s not what they’re saying – the genes for morphology and colour are probably the same. We don’t have convergent evolution here, rather one where colour has not diverged a lot.
“the two plover species have high levels of genetic divergence on their sex chromosomes”
What about the other chromosomes, besides the Z?
What does it mean “species”?
https://en.wikipedia.org/wiki/Plover
“cycling sea level changes” ?
Melting ice?
Pw – the divergence in the other chromosomes was about half that of the Z.
PW: “What does it mean “species”?”
Good question.
From the article:
Seems to be a rather generous (as in meaningless) definition of species if they can still reproduce with each other.
The taxonomists find finer and finer distinctions and features to claim a new species which then allows them to name it. (Taxonomists love naming things) These may be no more than local adaptions in this family of birds. No one wants to do the hard work of seeing if hybrids of these various genera will produce fertile offspring (they often do in zoos and they seem to admit it in the article). It would result in radical trimming of Darwin’s tree of life, and severely limit the taxonomists.
So Materialists/Darwinists/Neodarwinists/Evo-Devoists (pick your latest fashionable designation) need speciation. The fossil record is a bust. Whole families just show up, change little if any, and then disappear. So that leaves speciation as the bottom line evidence for evolution. If in fact it’s only adaption and the whole concept of species is in doubt where does that leave them? Thus they play fast and loose with the definition of species.
Bob O’H, Latemarch,
Thanks for the clarifying explanations.
Do those birds have the same number of chromosomes?
How do their chromosomes differ between those two populations? Different lengths, structures, loci, alleles?
Maybe the real lesson of this discovery is that coding genes are not that important, a position that ID has taken for quite some time. That is, the ‘blueprint’ of life is not found in the coding genes–which are no more than a “material’s list,” but in the non-coding regions–you know, “junk DNA.”
ID maintained, all along, that “junk” DNA was very, very likely not going to turn out to be “junk” DNA. Of course, this is how things did turn out. This paper simply shows how malleable ‘coding genes’ can be, but that essentially they’re not ‘essential.’
Amusingly enough, the birds aren’t identical and the genes aren’t different (or at least, the are not genetic variants present in only one population).
.
Nope, paper is here, not limited to protein coding genes. (And, of course, the usual conflation of “junk DNA” and non-coding DNA is wrong).
I bet that with the right chef and the right gravy, no one could tell the two apart. They would never know they were eating two different species. 😎
ET
It used to be that a guy with a sleeve tattoo was a biker that would beat you to a pulp.
Now a guy with a sleeve tattoo is a chef drizzling a raspberry balsamic vinegarette over your breast of plover.
https://jeb.biologists.org/content/jexbio/218/1/7.full.pdf
Pw:
Thanks for the article. Evolution beyond neo-Darwinism: a new conceptual framework by Denis Noble
Noble is one of the “Third Way” evolutionists that at least recognize that they have a causality problem. I love this quote at the end of the article
We’ve certainly seen some of our Materialist commenters fall into some of those holes time after time.