The evolutionary relationships and biogeographical history of Elkalyce cogina, a small butterfly endemic to Brazil and neighbouring Argentina, are long-standing puzzles. The species was originally described within the genus Lycaena, but because no close relatives were attributable based on morphology, the genus Elkalyce was created. Now, IBE scientists lead by Roger Vila and Gerard Talavera have used molecular tools and novel biogeographical and life history data to clarify the taxonomy and distribution of this butterfly. The results were published last week in the Journal of Biogeography.

The study of the affinities and origins of this species is crucial to understanding the processes that led to the observed patterns of species distribution and diversification worldwide. Normally, the history of how species have spread through the planet can be studied by means of a reliable and abundant fossil record. However, in the case of butterflies, the fossil record is extremely poor so the history of biogreographical distribution has to be inferred from genetic studies.

Thanks to DNA data, researchers at IBE have been able to discover the remarkable trip followed by this species' ancestors to reach Brazil. The results show that this species is the sister of a group of butterflies that mainly lives in South-East Asia. Approximately 10 million years ago, the ancestor of E. cogina did all the way to South America from Asia via the Bering Strait, and crossing the American continent from north to south. The most surprising aspect is that, despite colonizing the New World, the butterfly did not diversify for 10 million years, and thus becomes a fascinating exception when compared to other lineages with similar biogeographic histories.

The title of the original article, "One-note samba: the biogeographical history of the relict Brazilian butterfly Elkalyce cogina", pays tribute to a famous samba by Antonio Carlos Jobim and Newton Mendonça that says the notes should not be diversified: it's better to centre the efforts in what you know you are good at. The main melody line, is unique because at first consists of a long series of notes of a single tone.

Original Article: Talavera G, Kaminski LA, Freitas AVL, and Vila R (2015). One-note samba: the biogeographical history of the relict Brazilian butterfly Elkalyce cogina. Journal of Biogeography