A half century ago my graduate research was stimulated and influenced by the important unpublished Etheridgean thesis (Etheridge, “1959”, 1960). As an E.E. Williams student, I was an adopter, user, and later coiner of informal names for seemingly natural evolutionary groups in the diverse genus Anolis. In most cases, I was building upon (sometimes tweaking) the foundation of Etheridge’s classification. I believed then and believe now that the use of informal names for natural groups worked well for communicating evolutionary hypotheses both to specialists in our field, and to a broader audience of professional and amateur biologists who are likely not well informed about the nomenclatural history of these lizards.
Nicholson et al. (2012) believe otherwise. Here is their overview, page 13:
“The role of systematics is to advance our understanding of biological diversity in the natural world. Its practitioners are the guardians of the knowledge produced by past generations and responsible for the rational interpretation of new data and their implications. Within this framework, phylogenetic inference has consequences that we think bind its practitioners to produce a systematic classification of the studied organisms. Such a classification must be founded on the inferred evolutionary relationships and dictated by the canon of monophyly.”
I support that.
This note, then, is neither about the role of systematics, nor the interpretation of phylogenetic analyses (the Nicholson et al. presentation is comprehensive and extremely valuable). Rather it concerns their conclusion to the cited paragraph about the use of Anolis, as the generic name for the entire clade. They write:
“the single genus concept can be a hindrance to scientific communication regarding evolutionary events and directions of future research.”
I believe exactly the opposite. Specifically, I believe that the single genus concept enhances scientific communication and suggests directions of future research. There is no right and wrong here. This is my opinion. They have presented theirs.
I think it’s fair to say that most working systematists appear to have a sense that somehow “species” are “real,” and can be more or less defined…even if definitions get a little leaky around the edges, such as what to do with parthenogenetic clones, or allopatric island populations.
But unless I am mistaken, there is no accepted or acceptable definition, or even concept of “genus.” The “reality” that systematists seek is the elucidation of the cladistic history of a taxon…the branching points , the divergence times, etc. But how we name these different branches relies heavily on convenience, convention and history.
In the paragraph cited above, Nicholson et al. write that “the current practice of treating all dactyloids as comprising a single genus underemphasizes the evolutionary diversity within the family and obfuscates major biological differences among clades.”
This is pure conjecture. The category “genus” does not convey any amount of diversity—morphological, genetic, or physiological—within a family. I’ve long felt that an ornithologist’s bird family would be a herpetologist’s genus… but so what?
Assume that the 8 clades of Nicholson et al. are “real,” and that all emerge from a common ancestor. Now ask, what information is lost by retaining the generic name Anolis for all eight clades?
For example, look at Nicholson et al. Figures 4a&4b (p.10) summarizing “results of the Bayesian phylogenetic analysis.” Whether the names on the far right hand side of the figures are genera or subgenera, or informal categories, they are equally interpretable and convey identical information content.
I believe that much information would likely be lost, and much confusion would ensue by using 8 names in place of one for a taxon that has almost risen to Drosophilian status. The genus Anolis has been a focus of all sorts of research programs for the past half century.
Here are some issues:
(1) Literature searches become difficult and new herpetologically oriented students, or experimentalists not especially interested or aware of taxonomic history, are likely to miss important stuff through confusion of a name.
(2) Museum collections would have to be physically rearranged. Not trivial.
(3) A multiplicity of generic names might discourage certain types of obvious comparative studies, from patterns of ecomorph evolution on large islands to thermal biology, to reproductive biology, to patterns of karyotype evolution. I wonder whether, as a graduate student , Schoener would have thought about examining patterns of head size and body size on islands inhabited by solitary species or species pairs of in some cases Norops (on Curacao), or Dactyloa (southern Lesser Antilles), or Ctenonotus (northern Lesser Antilles)? We’ll never know… but it is not unlikely that the appropriate questions were asked, and research generated and patterns observed because these were treated as one genus.
(4) Amateur naturalists could never figure out to what genus a particular specimen belonged , as most of the genera are not “conventionally” diagnosable. This may be a weak argument if we were dealing with newly described or newly discovered taxa… but such is not the case.
In summary, I would suggest that mucking around with well established generic names that represent monophyletic clades sows unnecessary confusion, inhibits research, and should be undertaken only when there is a clear and compelling reason for change.
As an afterthought, …what if further, new research shows that the 8 Nicholson et al. genera do not hold up as monophyletic lineages? Then the rules of nomenclature will force wholesale revisions of generic definitions, and an entire new set of names may have to be dredged up or coined to confuse the elderly. None of this advances “Science”…as I conceive of science, nor natural history, as I conceive of natural history.
Am I just an old conservative? Am I missing the boat somewhere?
Etheridge, R. (“1959”, 1960) The Relationships of the Anoles (Reptilia: Sauria: Iguanidae): An Interpretation Based on Skeletal Morphology. PhD. Dissertation, University of Michigan, Ann Arbor, 236 pp.
KIRSTEN E. NICHOLSON, BRIAN I. CROTHER, CRAIG GUYER & JAY M. SAVAGE (2012). It is time for a new classification of anoles (Squamata: Dactyloidae). Zootaxa, 3477, 1-108
Skip Lazell
Bravo George! Right on: delighted to join you elderly curmudgeons’ club. As GG Simpson pointed out, genera need to be easily recognized, preferably in the field.
George Gorman
Skip, I hope to see you again one of these days….while we’re both still kickin.
Where are your whereabouts?
George