Mullerian mimicry and the colouration patterns of sympatric coral snakes

We examined museum specimens of Micrurus brasiliensis, M. frontalis, M. ibiboboca, M. lemniscatus, and M. surinamensis by taking high-quality digital photographs from the dorsum of 1528 preserved snakes. We measured the number of red rings, relative length of red rings (length of red ring / total length), relative length of external black rings ((length of black ring I + length of black ring III) / total length) / 2), relative length of white rings ((length of white ring I + length of white ring II / total length) / 2), and relative length of internal black rings (length of black ring II / total length). We calculated the colour variation through the geographic distribution of each species coupled with a multivariate spatial analysis approach.