Anolis sagrei from the Bahamas
A dozen years ago, Jonathan Losos explained in these pages how lizards sometimes end up with multiple tail tips, a phenomenon known as tail furcations. My student Tim Baum and I recently published a review of this phenomenon for all lizards and found that published reports of tail furcations exist for 250 species! For the readers of Anole Annals, I wanted to present a quick review of this phenomenon in the genus Anolis.
Among the many lizard records we located were only ten species of Anolis (4% of the total), slightly below the expected proportion of Anolis out of all lizards (6%). But these anoles do have a nice variety of multi-tails! Overall, they conform to the concept that two tails are the most common occurrence (64% of known anole cases). Two-tailed lizards can be divided into those who have a forked tail that is less than half the tail length (i.e., the extra tail starts nearer the tail’s end), which is known as a bifurcation. The other option is that the additional tail begins closer to the beginning of the tail, and this is known as a duplication. Duplications are relatively rare in Anolis, with only 22% of the two tails originating close to the body.
What is interesting about anoles is that aside from two-tailed lizards, three tails are known from Anolis equestris and A. grahami, and there is even a four-tailed A. sagrei! Most lizard genera stick with the two-tailed version, so anoles have it going on!
Clearly, with well over 400 species of Anolis listed in the Reptile Database (and I don’t want to quibble about genus assignments here), many more species should be out there with furcated tails. Based on our research and literature review, these encounters are serendipities of fieldwork, so keep your eyes open and mobile phone cameras ready – and then publish the new records!