Monday, April 23, 2007

Field guide to NY herps: Part III

Today, I made my way through the lizard and snake section of Gibbs et al.'s new guide to New York herps. The detailed natural history information continued to impress. There are lots of interesting nuggets, even for those who think they know something about New York herps (i.e., me). I had long been under the mistaken impression, for example, that introduced Italian wall lizards were surviving the winter in human habitations, but I learned on page 216 about Burke et al.'s finding that the species actually survives under soil in the frost-free zone. Gibbs et al. also offer a warning about the future spread of this species. This and other example highlight the book's overall attention to the past and future conservation status of New York herps. The author's detailed remarks about the decline of short-headed gartersnakes was also enlightening.

As much as I hate to keep harping on the same deficiencies, the book's suggested methods for species identification and maps remain somewhat problematic. Readers unfamiliar with the jargon of reptile scalation, for example, will be frustrated by the absence of a figure illustrating key traits: the book's advice on distinguishing coal from five-lined skinks refers to the presence of a single postmental scale in coal skinks without providing an indication of what a postmental scale is. In other cases, the photos fail to illustrate interesting traits like the colorful ventral markings of fence lizards. Regarding the maps, a lack of detail continued to bother me. The account of the ring-necked snake, for example, mentions that they are "rare or absent from the extreme north along the southern Lake Ontario floodplain" and refers the reader to Map 7.7., but this figure simply indicates the presence of the species across the entire state.

Although I'm through the species accounts, the fourth and final part of my review will cover the remaining sections on "Threats", "Legal Protections", and "Conservation", as well as offering a final summary.

Saturday, April 21, 2007

Field guide to NY herps: Part II

Today, I'll offer my thoughts on the frog and turtle sections of Gibbs et al.'s wonderful new volume on the amphibians and reptiles of New York state. I was immediately impressed the natural history content of the frog section relative to the salamander section. For the frogs, we're offered much more specific information about how and when breeding occurs, for example: in the salamanders section, we're rarely told anything more than that breeding occurs in "early spring", but for the frog section this type of information is much more detailed (i.e., "Gray tree frogs appear after early spring rains and are active well into the autumn months. Breeding can be prolonged and extend up to 2 months, usually between mid-May and late July, later than other frogs in New York..."). More information is also offered regarding the conservation status of frogs than salamanders. Although these apparent shifts in detail could be due to the fact that frogs of NY are better known than the salamanders, I don't think this is the whole story. Perhaps different authors were responsible for these two sections and those writing the salamander section felt that the detailed information in the frog section was over-kill? Personally, I find the frog accounts much more helpful.

Sadly, other, more serious deficiencies of the salamander section are not remedied: the maps are still a bit vague and useful identifying information or photographs of tadpoles and egg masses are lacking.

I'll have to admit that I've mostly just skimmed the turtle section. Interesting facts aren't hard to come by in this section, often in the "Other Intriguing Facts" section found at the end of each species' account. For example, we're told of a violent encounter between eastern mud turtles and the impact of hikers on populations of wood turtles. Not many typos in this book so far, one of the first I've see is the addition of an extraneous comma on page 190: "It has been, introduced throughout New York..."

The final part of this review will be up tomorrow...

Tuesday, April 17, 2007

Finally, a guide to the herps of NY!

Since the age of fourteen, I've yearned for a comprehensive modern field guide to the herpetofauna of my home state. Six of the state's most distinguished herpetologist have now teamed to fill this void with "The Amphibians and Reptiles of New York State: Identification, Natural History, and Conservation". I hope to offer my comments in this book in a few parts, starting today with the introductory material through the salamanders.

Because I'm so grateful for the effort the authors devoted to this impressive volume, I'll start with the positives. First, this book is well-written and a joy to read (I just breezed through the first 100+ pages over a cup of coffee). Another strength lies in the detailed accounting of each species' natural history and conservation status. Information on where to find each species (both regionally and locally) and basic information on reproduction and diet are offered for each species. In some cases, the natural history lessons extend to the photographs; see, for example, the Plate 3c of the early Spring breeding Jefferson's salamander dispersing over snow.

This said, I feel compelled to point out a few disappointing shortcomings. The first is a lack of a key, or even a set of figures that illustrate diagnostic traits. Important traits like the light line from the eye to the corner of the mouth in Desmognathus, for example, is seen only in a whole body shot of D. ochrophaeus in Plate 10c. A labeled close-up of this and other traits would prove invaluable to those who are just beginning to learn the fauna. A lack of detail on the identification of larval forms is particularly striking. Unfortunately, I'm left to conclude that his book falls a bit short on the "Identification" portion of the subtitle. In many cases, Conant and Collins' guide to the herps of the eastern US (part of the R.T. Peterson series) will prove to be a more valuable reference for species identification.

For those who are already well versed in the identification of New York's herps, however, the maps may be a bigger disappointment. Although they are based on a impressive public effort to develop an atlas of NY herps that extended form 1990 to 1999 and included more than 59,000 records, the maps are often lacking important details. For example, many species of salamanders appear to be absent from the Great Lakes plain and St. Lawrence Valley, but this is only occasionally illustrated. This pattern is noted, for example, in A. jeffersonianum, but not illustrated in the map. The absence of northern duskies from this area is illustrated, but their noted absence from higher altitudes in the Adirondacks is not. Simply put, the shaded maps in this volume don't do justice to the subtleties of many species' distributions. We need dot maps!

On a personal level, I also found the lack of evolutionary and phylogenetic information disappointing. Although this complaint stems in part from my own interests and may seem unjustified in a regional guide, the exclusion of this perspective deprives readers of information on the biogeography history of New York's herps, as well as information on the evolution of their natural histories. Readers would surely be interested to know that the closest relatives of our hellbenders are the remarkable giant salamanders of China and Japan. By noting the position of this species on the salamander tree of life would also inform readers about why this is our state's only native salamander with external fertilization.

More tomorrow...

Monday, April 16, 2007

The Evolution of Big Snakes: A New Perspective on Their Biogeography and Morphological Diversification

Last April, Noonan and Chippindale published a wonderful new phylogeny of boid snakes (a group that includes the Boinae [i.e., all of the well-known boas from the New World, Madagascar, and the Pacific] and the Erycinae [i.e., the African sand boas plus North America's rubber and rosy boas]) with fascinating implications for the group's biogeographic history and morphological evolution. I can't find anything to complain about in their phylogenetic analyses, which include thorough parsimony, likelihood, and Bayesian analyses of four nuclear and one mitochondrial gene. Their results should be considered the definitive modern statement on phylogenetic relationships in the Boinae.

In addition to supporting a late Cretaceous (~90 Ma) Antarctic land bridge between the New World with Madagascar (yes, that's right, an Antartic land bridge), Noonan and Chippindale's results have some mind-blowing implications for the evolution of morphological diversity in the Boinae. Two particularly stunning examples are noteworthy. First, they find moderate support for the paraphyly of Epicrates with respect to anacondas (Eunectes). Thus, it appears that the shared morphological and ecological features of Caribbean and mainland Epicrates have experienced prolonged evolutionary stasis during a longer interval of time than that required for the evolution of their distinctive evolutionary cousins (the anacondas). A second example shows how similar selective pressures can drive independent evolution of remarkably convergent morphologies. This point is made by the sister group relationship between the burrowing African genus Calabaria with the larger terrestrial/arboreal species on Madagascar (Sanzinia and Acrantophis). This is noteworthy, of course, because Calabaria now appears only distantly related to other, morphologically similar, burrowing taxa. Needless to say, these results drive another nail into the coffin of Kluge's ill-considered taxonomic revision that unified New World Boa with Madagascar's endemic genera. Kluge's results, which were based on morphological analyses, confound not only biogeography, but also a fascinating story of convert evolution.