Blue Iguana Recovery Program

From Subspecies to Species

Mar 14th, 2005 | By | Category: Blues in the Local Press

It’s official! No longer classed as a subspecies of the Cuban Iguana, The Grand Cayman Blue Iguana is now formally recognized as a species, unique only to the island of Grand Cayman. You can download the technical paper at Go to the “PDF Gallery” to obtain the entire document.

The following is The Introduction from the Technical Paper:

The strikingly blue rock iguanas native to the island of Grand Cayman were originally described as Cyclura macleayi lewisi(Grant, 1940). Schwartz and Carey (1977) established the currently accepted nomenclature, Cyclura nubila lewisi Grant. They noted that the Grand Cayman form was a strongly distinct subspecies of Cyclura nubila and emphasized its overall bright blue coloration. They recorded modal differences in head scalation, but identified no uniquely diagnostic scale characters.

More recently, Malone et al. (2000) used mitochondrial DNA analysis to re-examine the phylogeography of Cyclura and raised an unexpected question on the taxonomic rank of the Grand Cayman form. Their analysis demonstrated that C. n. lewisi has diverged from C. nubila at least as far as the Bahamian Rock Iguana, Cyclura cychlura. The latter is a currently recognized species with three subspecies; the distinctiveness of two of them was supported by the mtDNA analysis. Malone et al. (2000) also found that C. nubila caymanensis, native to Cayman Brac and Little Cayman, is more closely related to C. nubila nubila than C. nubila lewisi is to either. The mtDNA evidence therefore suggests C. nubila lewisi should be considered a species.

An active conservation program for critically endangered C. n. lewisi (Burton 2000) is currently underway on Grand Cayman; it provides ready access to large numbers of all age classes for detailed examination. I present here the results of further investigation on the scalation and color pattern of C. n. lewisi, and integrate the results with other lines of evidence, using the general lineage concept of species (de Queiroz 1998, 1999) to reassess the taxonomic status of C. n lewisi. To read the entire document, go to the PDF Gallery to download it.

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