Excerpts from Jim Conrad's
from the July 9, 2017 Newsletter issued from Rancho Regensis north of Valladolid, Yucatán, MÉXICO
CENTRAL AMERICAN CHECKERED-SKIPPER
A few days ago I sent volunteer identifier Bea in Ontario the skipper-type butterfly shown at the top of this page. A side view is shown below:
This looks a good bit like the Tropical Checkered Skipper we've already documented at http://www.backyardnature.net/yucatan/mariposa/butt034.jpg
However, there are subtle differences with the white spots. The question, then, was whether the differences are great enough for specialists to have decided that they're different species. Bea's battle to figure things out provides a good insight into not only one little corner of the world of butterfly classification, but also how a talented and persistent amateur lepidopterist can use the Internet to figure things out.
First of all, since this week's mystery butterfly was so similar to the Tropical Checkered Skipper we'd already seen, Bea was pretty sure that if we didn't have the same species, at least surely it was a member of the same genus, the genus Pyrgus.
Looking at pictures of species of the genus Pyrgus at the ButterfliesofAmerica.Com and the ButterfliesandMoths.Org website, Bea came to this conclusion about this week's mystery skipper: Probably but not with 100% certainty it was the Central American Checkered-Skipper, PYRGUS ADEPTA.
Bea further wrote about the various Pyrgus species it could be: "Not Desert, not Orcas, not Tropical, but I can't rule out Common Checkered-Skipper or White-checkered completely. I need more time to research."
Having the search narrowed down so, I looked to see if anyone has recently published a list of Yucatan butterflies on the Internet, and they had. It was "Especies y géneros por familia de lepidópteros de Yucatán" by Flor Rodríguez Reynaga and others, an undated entry on a Biodiversidad y Desarrollo Humano en Yucatán webpage. For identifiers of Yucatan butterflies this list is a great help, because it provides an idea of which species are and are not present here. You can download the document for free in PDF format at the Seduma.yucatan.gob.mx website.
That document lists four Pyrgus species for Yucatán. Of those four, Bea had disqualified two. When I looked at the remaining two on the Internet, I decided that, as usual, Bea was right, and we have a new-for-us species, the Central American Checkered-Skipper.
At https://www.butterfliesandmoths.org/species/Pyrgus-adepta the ButterfliesandMoths.Org page for the Central American Checkered-Skipper tells us that the species is distributed from Mexico through Colombia in South America. Also, in the past it was often treated as a subspecies of the Common Checkered-Skipper, Pyrgus communis, which helps explain why Bea had problems disqualifying that species.