The specimen had genitalia that looked different from the typical Chryxus, and it was larger and darker overall. It also had bigger white specks on the underside of its penny-colored wings, giving it a frosted look.source: http://news.nationalgeographic.com/2016/03/160316-tanana-arctic-butterfly-alaska-hybridization-new-species-science/
A scientist organizing butterfly specimens in a museum collection made a startling discovery: What people had thought was a variant of a common species is actually a totally new organism, and one with an interesting evolutionary history to boot. And what’s more, the new species may be the only type of butterfly endemic to Alaska, meaning it is found there but nowhere else.
A group of eight scientists from three countries has named the new insect the Tanana Arctic, or Oeneis tanana. It’s the first new butterfly species described from Alaska in 28 years, and the research is now published in the Journal of Research on the Lepidoptera.
“To me it was surprising that no one had noticed this before,” says Andrew Warren, a study author and lepidopterist (or butterfly expert) at the University of Florida in Gainesville.
In 2010, Warren was going through the collection at the Florida Museum of Natural History when he came across a specimen labelled as the Chryxus Arctic butterfly, and yet it “didn’t look right.”