Anole taxonomists: Richard Etheridge, Jay Savage, Ernest Williams, S. Blair Hedges, Craig Guyer, Steve Poe
Anolis has been recognized as an extraordinarily large genus for decades, but Nicholson et al. (2012) are not the first to propose recognition of multiple anole genera. Indeed, all of the generic epithets used in Nicholson et al.’s new classification were coined in 1934 or earlier and most are from the early 19th century. This early proliferation of generic epithets resulted primarily from the fact that a comprehensive systematic treatment of anoles did not appear until the mid-20th century. My purpose here is to review the history of generic level anole classification in the years following Richard Etheridge’s pioneering PhD thesis of 1959/60. I believe that this historical perspective provides necessary context for evaluation of Nicholson et al.’s proposed revisions, and helps explain why the genera in their revised classification appear so rarely in the literature relative to Anolis (see Mahler’s recent post on the topic of genus name usage).
To briefly summarize the history of anole genera, the vast majority of work published over the past half century has formally assigned all, or nearly all, anole species to Anolis. The only noteworthy exceptions to this include (1) assignment of a small number of morphologically unusual species from the mainland, Cuba, or Hispaniola to Phenacosaurus, Chamaelinorops or Chamaeleolis into the 1990s and (2) assignment of species belonging to Etheridge’s β section of Anolis to Norops by some anole biologists working primarily in Central America during the 1990s through the 2000s.
Etheridge’s dissertation, which was completed in 1959 but not available until 1960.
In 1959, Richard Etheridge, a PhD student with Norman Hartweg at the University of Michigan, submitted a thesis that relied on remarkably thorough analyses of skeletal morphology to revise anole classification. At the beginning of this study, Etheridge recognized Anolis as a diverse genus containing over 200 species, but also identified ten other anole genera that contained only one or a few species: Chamaeleolis, Phenacosaurus, Chamaelinorops, Tropidodactylus, Audantia, Mariguana, Diaphoranolis, Xiphocercus, Deiroptyx, and Norops. Etheridge found the first four genera listed above to be “so unusual” morphologically that they warrant continued recognition, but the rest were synonomized with Anolis because his morphological analyses found them “to be not at all separable from Anolis, or to be based on characters so trivial that they are here considered as identical with Anolis.”
Etheridge left the large genus Anolis intact in spite of the fact that, at the beginning of his study, he “thought it very likely that the great number of species in the genus Anolis might be dividied into several groups, and that each of these might reasonably be accorded generic status.” His reason for leaving Anolis intact was that “the relationships of the various species of Anolis have proven to be far too complex to be treated in so simple a manner as the proposal of formal generic groupings.” Rather than naming new genera, Etheridge informally characterized sets of species at “several different hierarchical positions between the genus and species” as “groups,” “complexes,” “sections,” or “series.” The aspect of Etheridge’s classification that drew the most attention was his division of Anolis into α and β sections distinguished primarily on the basis of basis of a striking difference in the morphology of tail vertebrae (see figure above from Etheridge’s disseration).
