Papilio cresphontes is actually two separate species!

[Adam Cotton]

An incredible discovery was published on 23rd December 2014 in ZooKeys.

The citation is:
Shiraiwa K, Cong Q, Grishin NV (2014) A new Heraclides swallowtail (Lepidoptera, Papilionidae) from North America is recognized by the pattern on its neck. ZooKeys 468: 85–135. doi: 10.3897/zookeys.468.8565

The full paper can be accessed here or downloaded as a pdf:
zookeys.pensoft.net/articles.php?id=4409

This excellent paper details this extraordinary discovery in such a way that it is clearly not the figment of anyone's imagination. I also commend the exemplary manner in which all aspects of nomenclature, taxonomy and issues related to the new species and its relatives are considered in a clear and Code compliant manner.

Here is the abstract:
Heraclides rumiko Shiraiwa & Grishin, sp. n. is described from southwestern United States, Mexico, and Central America (type locality: USA, Texas, Duval County). It is closely allied to H. cresphontes (Cramer, 1777) and the two species are sympatric in central Texas. The new species is diagnosed by male genitalia and exhibits a nearly 3% difference from H. cresphontes in the COI DNA barcode sequence of mitochondrial DNA. The two Heraclides species can usually be told apart by the shape and size of yellow spots on the neck, by the wing shape, and the details of wing patterns. “Western Giant Swallowtail” is proposed as the English name for H. rumiko. To stabilize nomenclature, neotype for Papilio cresphontes Cramer, 1777, an eastern United States species, is designated from Brooklyn, New York, USA; and lectotype for Papilio thoas Linnaeus, 1771 is designated from Suriname. We sequenced DNA barcodes and ID tags of nearly 400 Papilionini specimens completing coverage of all Heraclides species. Comparative analyses of DNA barcodes, genitalia, and facies suggest that Heraclides oviedo (Gundlach, 1866), reinstated status, is a species-level taxon rather than a subspecies of H. thoas (Linnaeus, 1771); and H. pallas (G. Gray, [1853]), reinstated status, with its subspecies H. p. bajaensis (J. Brown & Faulkner, 1992), comb. n., and Heraclides anchicayaensis Constantino, Le Crom & Salazar, 2002, stat. n., are not conspecific with H. astyalus (Godart, 1819).

Adam.

[mygos]

Hey Adam, as a moderator, you should have checked what was going on there, as Radusho already posted the same article

A+, Michel

[wollastoni]

Even moderators can make an error !

[deliasfanatic]

Amazing discovery and paper - I read it last night. I'd never have thought that pallas/anchicayaensis are separate species from astyalus. Adam, what's your thought on the "percentage difference" DNA?

[wollastoni]

Adam has already celebrated Xmas !

[Adam Cotton]

Dec 24, 2014 17:33:13 GMT mygos said:

Hey Adam, as a moderator, you should have checked what was going on there, as Radusho already posted the same article

A+, Michel

Michel,

Yes, I admit I didn't check the other sections of the forum before posting this, although I did look at the latest topics on the home page.

Anyway, it's not really a race to post news , and hopefully my post will give everyone the basic information in the paper, even if they don't want to download the paper at source.


Adam.

[Adam Cotton]

Dec 24, 2014 17:48:55 GMT deliasfanatic said:

Amazing discovery and paper - I read it last night. I'd never have thought that pallas/anchicayaensis are separate species from astyalus. Adam, what's your thought on the "percentage difference" DNA?

Well, if this paper was based on percentage difference of the COI sequence alone I would be much more sceptical about the validity of the main finding, vis the cryptic species within what everyone calls cresphontes, but there are clear morphological and diagnostic differences between the two as well.

In reality significant percentage difference in DNA sequences is often a clear indication that there is more than one taxon involved, but this is not always the case. There is a good argument for using it to spot possible issues that need further investigation, but I would hesitate to rely wholly on this one indicator.

With regard to pallas in particular, a study I was involved in using both mt and nuclear DNA (Lewis et al. 2014, cited in this publication) found that ornythion was nested between astyalus and pallas indicating that pallas should be treated as a separate species to astyalus.

Adam.

[Adam Cotton]

Here's an interesting post from Nick Grishin (reproduced from TILS Leps-talk e-mail group) about Koji Shiraiwa and the history of the discovery:

It was a real treat to collaborate with Koji! This is his discovery dating
a decade ago (and a product of great diligence in his fieldwork), he
studied dozens of specimens, prepared, photographed and measured genitalia
(his genitalia pictures are simply terrific!), detailed all the
differences between species, and suggested a hypothesis about how
speciation happened (a very imaginative and compelling one!). We just
helped a little here and there to support his conclusions with DNA
sequences and small technicalities. It was a fun project and a very
rewarding collaboration.

Indeed, we don't know much about them. And this is just a first step to
the genomics study of the two species with hopes to understand their
interactions in the overlap zone and speciation processes at work.
Western/Eastern split passing through TX is a generality we see in a few
groups. I hope cresphontes/rumiko pair will make it in ranks to model
organisms in a study of speciation. They are common, accessible and large.

I'm glad that the paper came out during the holiday season and am honored
to be a part of it. Thanks Koji!

Happy Holidays! n