Author: Jonathan Losos Page 33 of 129

The last week has seen a spirited discussion of the pros and cons of splitting recognized genera into multiple, smaller genera. We’ve had 34 comments already. Check it out! And if you’re an advocate of splitting genera, that viewpoint has been getting the short end of the stick and could use more support.

As a tangent, the topic of subspecies has come up, and David Hillis has strongly argued for reviving its use. Here’s what he has to say:

First, I don’t think either species or subspecies are “clades.” Species are lineages (the branches on the tree of life). Sexual recombination among individuals results in tokogenetic relationships within species. Clades, on the other hand, are monophyletic groups of lineages on the tree of life. Rather than being defined by tokogenetic relationships, they are defined by phylogenetic relationships.

Traditionally, subspecies are geographical races of species. In other words, they are geographically distinct populations that nonetheless meet and interbreed at contact zones. Sometimes, these contact zones are very broad, as with broad-banded versus southern copperheads. If the contact zones are very narrow, and there is strong evidence that the contact zone is a genetic sink (there is no gene flow across the zone, because of strong selection against hybrids), then I agree that the two entities can be considered separate lineages, and hence species. But in many recent cases, as with the copperhead example, there is abundant evidence that the contact zone is NOT a sink, and that there is NO selection against hybrids. In this case, I disagree strongly with the authors who proposed to split these subspecies into distinct species. That is inconsistent with any lineage species concept…there is a huge area where these two forms intergrade, with no evidence of any loss of fitness. Thus, the two forms are geographical, intergrading races, or subspecies.

I think we will soon see a backlash against the splitting off of geographic races as species as well. Frank Burbrink (who was an author on the copperhead example I mentioned above) and I plan to write a pro/con article about this together, each arguing our respective points of view. Hopefully, this will re-kindle the conversation about subspecies.

Subspecies are unpopular right now because they were long abused in several ways. Inappropriate uses include (1) to describe non-geographic “varieties”; (2) to arbitrarily break up clines; and (3) to describe distinct, isolated lineages that clearly are species. But used in proper context to designate a geographically distinct race, they are certainly reasonable and often useful. They are rarely used in some groups, for several reasons: Groups like freshwater fishes have discrete ranges, so taxa don’t interbreed over broad areas. And many groups are too poorly studied to understand geographic variation. But in well-studied terrestrial groups (like herps), subspecies are perfectly reasonable and useful taxa to designate intergrading geographic races.

Over the last several years, ever since Nicholson et al. proposed dividing Anolis into eight genera, the topic of taxonomic splitting has periodically been discussed in these pages (for example, this post, its comments, and links to other posts).

The general question of when to split taxa recently has been revisited in several comments in AA. A week ago, David Hillis wrote:

“Anolis is a valid name for a monophyletic group on the Tree of Life. It is “special” as a genus only in that the genus name is used as part of a binomial for particular species. It doesn’t make sense to change the scope and application of generic names unless the names are actually misleading about phylogeny (e.g., if Anolis were polyphyletic, then that problem should be fixed). But splitting a valid, monophyletic genus into a bunch of smaller genera, and thereby needlessly changing the names of many species, without fixing any phylogenetic problems with the existing taxon names, is not science. It is just playing around with names. If someone wants to name the groups within genera, then do so…but there is no reason to change the meaning of a existing name (or the names of the all the affected species) in doing so. That is the kind of silliness that gives taxonomists such a deservedly bad reputation among biologists.”

Elswhere, David posted a flowchart on his recommended decision-making process about whether and how to divide recognized genera:

Ivan Prates, in line with comments he made in a recent paper on A. punctatus, then remarked:

“This seems more like a sociological matter.

During the ‘taxonomic revolution’ of the amphibians, about 10 years ago, the (perhaps?) most influential (or faster?) group was the splitter one, and their taxonomic scheme prevailed. Currently, nobody is upset about which species were once named as Bufo, Hyla or Rana. A few do care about Dendrobates – like Anolis, a sexy group with a body of dedicated investigators.

It seems that a single genus makes sense for the community that investigates dactyloid lizards more closely. On the other hand, those who deal with overwhelming levels of herpetological diversity in the tropics (waaaay beyond lizards) see benefit in more partitioned schemes, which correlate more closely to morphology and geography.

So, when we discuss names, it may be healthy not to forget about our diversity as investigators as well. About science, splitting Anolis is not science, but well, not splitting Anolis isn’t science either.”

Photo by Karen Cusick

From Daffodill’s Photo Blog.

Rush Limbaugh, that’s who! To wit: “But I love those little lizards.  They’re anoles, actually.  I love ’em.  They’re our buddies. They eat insects and all that.”

And it turns out that Jeb Bush is just like a cat chasing an anole. Read all about it here (or listen to it here), skipping to paragraph four if you want to get to the important, mostly non-political stuff.

In anticipation of its sesquicentennial in 2017, The American Naturalist has solicited essays commenting on overlooked or underappreciated articles published in the journal during the past 150 years. In this month’s issue, Manuel Leal and I comment on a 1970 paper by Stan Rand and Ernest Williams on how differences among anole species in their dewlap and display behavior contain multiple signals for species-recognition. Several decades later, the importance of redundancy in communication signals has become an important area of research, but years before, Rand and Williams sketched out the important issues, as well as identifying some still-unresolved questions.

Here’s the introduction to our essay:

“Why are animal signals so complex? This question continues to attract the interest of behavioral and evolutionary ecologists. In this Countdown article, we revisit a littlea ppreciated article in The American Naturalist published in 1970: “ An Estimation of Redundancy and Information Content of Anole Dewlaps” by A. Stanley Rand and Ernest E. Williams. As part of this piece, Rand and Williams argued that signal complexity can be explained by redundancy, a mechanism by which multiple components of the signals have evolved to increase the probability of eliciting a response from an intended receiver. We highlight this work because it presents one of the earliest demonstrations of the potential benefits of applying information theory to animal communication. In addition, the study demonstrates the insights that can be gained by evaluating signal evolution at the level of the community. Even today, when both theoretical and empirical studies evaluating the potential forces leading to signal diversity have fl ourished, evaluations at the community level are extremely rare.

More generally, in the spirit of the American Society of Naturalists, we wish to emphasize that the perspicacity of Rand and Williams resulted from the fact that their ideas were ultimately derived from a deep understanding of the natural history of their study organism. In particular, Stan Rand spent substantial time in the fi eld observing lizards, including 10 months studying the ecology and social dynamics of the Jamaican lizard Anolis lineatopus. This study reported detailed observations of many aspects of behavior, including detailed descriptions of the signaling displays used during intra- and interspecific interactions (A. S. Rand, 1967, “ Ecology and Social Organization in the Iguanid Lizard Anolis lineatopus,” Proceedings of the United States National Museum 122:1– 79). It was this familiarity with what animals actually do in nature—when and where they do it, interacting in which ways with what other individuals—that formed the basis of the theoretical constructs put forth in Rand and Williams’ s article. At its core, Rand and Williams (1970) is an elegant illustration of the art of being a naturalist, demonstrating how an intimate knowledge of the organism can serve as the building blocks for the formulation of new conceptual approaches (see H. W. Greene, 2005, “ Organisms in Nature as a Central Focus for Biology,” Trends in Ecology and Evolution 20:23– 27, and references therein).”

You’ll have to read the essay to get the full details, but here’s the conclusion:

“By detailed field study of the morphology and behavior of sympatric lizards, Rand and Williams (1970) were able to outline the applicability of information theory to lizard signaling behavior and species recognition two decades before those ideas became widely accepted. Moreover, they proposed important hypotheses yet to be investigated. This article demonstrates the key role that natural history plays, and will continue to play, in the conceptual development of animal behavior, evolutionary biology, and many other fields. Although the tools available for technological advancement in these fields are unparalleled, Rand and Williams’ s work demonstrates that observing animals in the wild and developing an intimate knowledge of their ecology serves as the raw material for the development of new and exciting areas of research. Thus, as we move into new frontiers, the appreciation of natural history must be an integral component of our approach and should be encouraged to a new generation of behavioral and evolutionary ecologists.”

Name that lizard (this one from Miami, not Grand Cayman). Photo by J. Losos

Tennessee lizard guru Sandy Echternacht writes in to AA about the green anoles that have shown up on Grand Cayman, in response to a post from several years ago:

I also think that it is difficult or impossible to distinguish U.S. Anolis carolinensis from U.S. A. porcatus in the field since you typically don’t have live, known A. porcatus for comparison. I think that Wes Chun is correct. Fully adult male A. porcatus are bulkier than A. carolinensis and I’ve seen some with what appear to be large bilateral calcium (?) deposits between the jaw and the neck that give them a bit of the look of a bulldog. I haven’t a clue how, for these two species, to distinguish subadult males and females in general. That shoulder bar (black; often with turquoise blue spots around the edges) is present in many populations of A. carolinensis in the Florida and further north and west, so it can’t be a reliable indicator of A. porcatus.

In addition, most of the relevant research on these issues today concentrates on spectral analyses of skin and dewlap colors, sometimes comparing these to spectral characteristics of the habitat which the lizards occupy. It’s time for a little old school field work. We need detailed narrative descriptions of color AND pattern of live A. carolinensis obtained under controlled conditions of light and temperature and in the maximum green and maximum dark color phases, and of patterning in both color phases, and these data need to be representative of populations across the entire mainland range of the species. If done by multiple investigators, these studies need to employ the same methods and standards. Geographic variation is obvious. Most A. carolinensis have pink to reddish dewlaps but those in southwestern Florida are grayish or greenish, I found a small population between Corkscrew Swamp Sanctuary and Immokalee, FL with pale orange dewlaps, and some males on Oahu, HI have lilac-colored dewlaps. As noted above, the shoulder patch can be entirely absent in a population or present but in frequencies that differ among populations. In East Tennessee, animals in the maximal dark phase are very dark brown to nearly black with no patterning (except a pale venter) whereas those near Gainesville, FL are a gray with a filigree pattern that is whitish in color. The frequency of females with pale middorsal stripes varies among populations. In a part of Withlacoochee State Forest, FL and in the green phase, the color is “chalky” green, along the coast near Ft. Myers it is a beautiful emerald green, further north, as far as Tennessee, it is more of a leafy green. As important as they are, spectral studies usually don’t mention pattern at all, and are carried out only in the green phase. Further, spectral values are of little value to someone working in the field not well versed in visualizing what they mean in the context of the lizard they are holding. I say all of this despite having a friend who is heavily invested in spectral studies. With all of this variation, and without having comparable data for A. porcatus, I’m not sure that we will ever be able to identify in the field with 100% certainty whether a green anole in South Florida (or the Cayman Islands) is A. carolinensis or A. porcatus with the possible exception of a large male A. porcatus with “calcium” deposits.

But I guess I could be wrong.

Six months ago, we had a post with some photos by Jesús Reina Carvajal of the lovely Anolis equestris potior. Jesús has now put some videos up on Youtube. There’s not a tremendous amount of action, but it’s nice to see such beauties in action. There are five clips in total–you can access the other four from the one above.

News-Journal/Mark Lane

The Daytona Beach News-Journal recently reported on a couple that has built an anole playground. Here’s the article:

The sign says “Lizard Land.” It’s a little sign. A lizard-sized sign, in fact. A sign marking a kind of lizard playground that Carol and Gary Mueller created in front of their home in Ormond by the Sea.

Anoles, small lizards that live around trees and eat insects, are a common sight in Florida yards. If you have enough time to sit very still outside, you’ve noticed their furtive movements up trees, down the side of the house and around the mailbox stand.

The Muellers have the time. “We’re totally retired,” laughs Gary, 70, a retired electrician. “Our biggest decision each day is whether to go to the ocean and fish or go to the river on the boat.”

One day they were sitting on the porch and noticed a particularly determined anole trying to make it to the top of a lawn ornament with a shiny globe on top.

“We were out there one time watching this little guy and he was trying like a dozen times to get up there,” recalled Gary. “So I thought, ‘I’ll make him a little bridge to get up there.’ ”

The little PVC ramp led to a more elaborate little lighthouse Gary made out of scrap wood laying around the garage. And that led to the miniature boathouse along with toy boats the couple found on the beach. And that led to the slide and the slide led to the little castle. It all turned into quite a little spread.

“The boathouse is their favorite part,” Carol. “It’s something to watch. They’re very smart little creatures.”

She said they now have a lizard population of about 15, “eight babies and seven big ones.”

It’s easy to tell them apart. “They’re very territorial, so each one sticks to its own part of the playground,” she said. Sometimes birds eat them but the local cats have mostly left them alone.

The current group of lizards are brown anoles, Anolis sagrei, a non-native lizard first noticed in the Florida Keys in 1887, according to the Florida Fish and Wildlife Conservation Commission, but not recorded in Volusia County until the 1980s.

The couple said they sometimes get green anoles, too, Anolis carolinensis, which are native to Florida. Their numbers are down because of competition from the brown anoles, but they’re holding on. And occasionally, the Muellers spot a third kind. “They look like little dinosaurs, I don’t know what they’re called,” Carol said.

Carol used to be a tram driver at Fort Wilderness at Disney World. “Casting felt I looked rugged,” she said. She liked the job and the people and being outdoors. She met her husband in the 1980s on New Year’s Eve. Both moved here from Orlando. They’ve been at their current home for two years.

“I don’t go there to Orlando anymore,” Gary said. “You need a helicopter to get there anymore.”

“Everything we need is in Ormond Beach,” agreed Carol.

Including the pleasures of sitting on the porch in the evening just watching lizards scamper around the garden.

Caption from article: A brown anole checks out a PVC ramp at Lizard Land in the yard of Ormond-by-the-Sea residents Carol and Gary Mueller. News-Journal/Mark Lane

Caption from article: Lizard tower is seen with an anole holding onto its side in the Lizard Land area of the yard of Ormond-by-the-Sea residents Carol and Gary Mueller. Photo courtesy Carol Mueller

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Nyctanolis pernix. Photo by Robin Moore

The Amphibian Survival Alliance reports: “Two rare salamander species lost to science for nearly 40 years have not only been recently rediscovered, but a consortium of international groups has protected some of the last remaining forest home of the salamanders just in the nick of time.”

One of these salamanders is Nyctanolis pernix, a long-limbed, arboreal salamander. Paul Elias and Dave Wake described the species in 1983 in the festschrift for Ernest Williams, Advances in Herpetology and Evolutionary Biology (in fact, it was the first article in the volume). The authors explained the species name as follows: “We name the new genus for its anoline apsect and nocturnal habitats (Gr., nyktos, night) and the species (L., quick agile) for its gymnastic behavior.

Read all about it on the ASA webpage.