joined an Oxford University biological expedition to the Cayman Islands. Lewis obtained two blue iguanas, a male and a female, which were later lodged with the Natural History Museum, London. Chapman Grant, in an article published in 1940, formally described the blue iguana as an separate taxon for the first time, classifying it as the trinomial C. macleayi lewisi. Albert Schwartz and Richard Thomas reclassified it as C. nubila lewisi in 1975, making it a subspecies of the Cuban iguana. In his 2004 article Frederick Burton repeatedly states Schwartz and Carey reclassified it in a 1977 publication, but he is mistaken. Burton, who runs the captive breeding program on the island, reclassified the blue iguana as a distinct species in 2004. Although it has almost identical head scale counts and patterns as C. nubila, most individuals of this taxon often have five auricular spines in as opposed to four in caymanensis, although this is not diagnostic, and individuals of the nominate subspecies shows either morphologies in similar proportions. Also most lewisi have an extra pair scales behind the prefrontals, although not always and individuals from the other populations may also have these. Thus Burton concluded that using scale characteristics these three taxa could not be told apart in a consistent manner. According to him most important difference between the lewisi population and the other two is skin color. Although skin color is a variable characteristic that is usually considered unsatisfactory in taxonomy, Burton thought that in this instance it might be appropriate. Although all three taxa hatch with the same color, as they grow older lewisi becomes more uniformly bluish, whereas the other taxa can be more variable in coloration, although Burton states that this characteristic is not reliable in many circumstances, such as rainy weather. Other reasons Burton gave for recognising lewisi as a separate species were geography, there is at least 108 kilometres separating the forms, which Burton then interpreted to mean that the populations were reproductively isolated, despite there being no reproductive barriers between the populations. Grant reported seeing caymanensis on Grand Cayman in 1940, but Burton states that this was likely a mistaken sighting made during rainy weather. Lastly Burton points to mitochondrial DNA analysis performed by Catherine Malone et al. in 2000; although the sample size was extremely small and there was some ambiguity, the different populations did have different haplotypes. Although Malone et al.