The Blue Iguana (Cyclura lewisi) is endemic to the island of Grand Cayman.
Its generic name (Cyclura) is derived from the Ancient Greek words
cyclos (κύκλος) meaning "circular" and ourá (οὐρά) meaning "tail", after the
thick-ringed tail characteristic of all Cyclura. Its specific name is a Latinized form of the name of the
scientist who first described this species, Bernard C. Lewis. Its closest relatives are the Cuban Iguana (Cyclura nubila) and
the Northern Bahamian Rock Iguana (Cyclura
cychlura), the three species having diverged from a common ancestor some three million years ago. The
species has a low genetic diversity but does not seem to
suffer the same lack of vitality that afflicts other such species of rock iguana. One theory is that the species
evolved from a single female Cuban Iguana (C. nubila nubila) with eggs inside her who drifted across the sea, perhaps during a
storm. It is distinct from the subspecies found on Little Cayman and Cayman Brac known as C. nubila caymanensis, although it can breed with this
subspecies and produce fertile offspring.
In 1938, Bernard C. Lewis of the Institute of Jamaica joined an Oxford University biological expedition to
the Cayman Islands. Lewis was able to obtain two Blue Iguanas, a male and a female, which were later lodged with
the British Museum of Natural History.
Chapman Grant, in a monograph published in
1940, formally described the Blue Iguana for the first time as Cyclura macleayi lewisi. Schwartz and
Carey established the trinomial (Cyclura nubila lewisi)
in 1977. They held that the Blue Iguana was a strongly distinct subspecies of the Cuban Iguana (C.
nubila), the species which it evolved from and can breed with. They emphasized its overall bright blue
coloration, and noted that further study could reveal it to be a distinct species. Frederick Burton reclassified
the Blue Iguana as a distinct species in 2004, after years of research comparing scale counts on the heads of
Caribbean iguanas, including those found on Little Cayman, Cayman Brac, Cuba, and the Bahamas, as well as
mitochondrial DNA analysis performed by
Dr. Catherine Malone, to re-examine the phylogeography of the different
The information on Bird Anatomy was contributed by: http://en.wikipedia.org/wiki/Grand_Cayman_Blue_Iguana