Anoles by the Numbers, Part I: Species Descriptions

As we all know, anoles are super diverse, but how diverse exactly? I often read that there are ~400 species of anoles, but how many precisely? And what about subspecies? And who described them?

Other AA authors (e.g. Greg Mayer, Rich Glor) have written about these questions in the past, but I’d like to add to this thread of anole history by using a great new resource – Peter Uetz’s reptile database. If you’ve ever googled any reptile species, you’ve probably found yourself on the Reptile Database website at some point, which has great info on species taxonomy, distribution, and often natural history. But recently, the database itself was published in Zootaxa with some interesting stats and plots of reptile species descriptions over time. The database is nuts – it contains information on the taxonomy of literally every reptile species! It’s a really incredible resource. And since it’s got every reptile, it has every anole! So I decided to explore the Anolis section of this database.

First, a couple details – the main data contained in the database is the species taxonomy, species description date, and author(s) of the description. For the main summaries here, I treat every author of a species description as “describer” whether they are the lead author or not, so if someone is a lead author on one description, but a coauthor on nine others, they will be summarized as describing 10 species. However, the info on number of coauthors per description and author order is retained. Also important to note that the database only contains current taxonomy; species or subspecies that have been sunk/synonymized/etc. won’t appear.

So let’s jump in! According to the Reptile Database at the time of publication (Jan 2018), there are 427 species of anoles. The number of new species descriptions peaked in the 1860’s, again in the 1930’s, and again in recent years. A number of you reading this are no doubt represented on this plot!

In total, Anolis species have been described by 171 different researchers. 21% of these species descriptions were done by just three people: E. D. Cope, Ernest Williams, and Gunther Koehler (currently active). Wow! Many of the remaining authors (47%) only described one species. The rest fall somewhere in the middle. After the three mentioned above, the researchers who have described the most species are Garrido (26), Boulenger (22), Barbour (18), Schwartz (18), Dumeril (15), Hedges (15), Poe (15), and Smith (15).

We’ve looked at how species have been described by different researchers, but I was curious to know how collaborative this process has been – how many authors normally contribute to a given species description? Well, 274 species descriptions were written by one author, 92 by two authors, and 61 by three or more authors. So most anole species were described by one or two authors.

As one might expect, as science as a whole has become more collaborative, the number of coauthors for species descriptions has increased over time. Almost all descriptions up to the early 1900’s were done by one author, while in the 2000’s that’s almost never been the case.

Now what about subspecies? According to the Reptile Database, there are currently 144 described subspecies from 36 different species. Most of those species have just a few subspecies, but a few of them have higher numbers, with a maximum of 11 in A. distichus and A. equestris. In the case of subspecies, 52% were described by just three people! Albert Schwartz, Orlando Garrido, and Skip Lazell (hi Skip!). Subspecies descriptions really hit a peak in the 1970s.

Most of the species that are split into subspecies are distributed in the Caribbean islands (33 of the total 36). Is this just because more phylogeography and taxonomy work has been done on the islands? Or is this another example of how patterns of diversification are different between mainland and island environments? I think probably the first.

Lastly, what was the first anole described? I thought it was A. carolinensis, but was surprised to learn that it was actually A. bimaculatus! Although that species was originally described as Lacerta bimaculata, later reassigned to Anolis. The first species actually described as Anolis was still not A. carolinensis though – it was A. auratus! Described by F. M. Daudin in 1802. So why is A. carolinensis the type specimen for the genus? Well, in 1963, Hobart Smith, Ernst Williams, and Skip Lazell petitioned* to change the type species to A. carolinensis due to a dubious prior designation of the genus type. The ICZN voted to approve their proposal, and granted the change in 1986**. For those interested in a deep dive, take a look at the 1986 decision**, which describes the back-and-forth between the the original proposers, the nay voters (Dupuis and Holthuis), a yay voter (Thompson), Jay Savage, and A. F. Stimson in the Bulletin of Zoological Nomenclature.

I hope you’ve enjoyed this brief history of Anolis by the numbers. Stay tuned for Part II: a look at the history of the Anolis collection at the Museum of Comparative Zoology!

* The Bulletin of Zoological Nomenclature. 1963. Vol 20: Pt. 1-6, pp 438-439.

** The Bulletin of Zoological Nomenclature. 1986. Vol 42: Pt. 1-4, pp 125-127.