Year: 2012 Page 32 of 47

The Caribbean skink radiation. Islands identified by name have (or had) mabuyine skinks; others--notably Cuba--do (or did) not.

Think Caribbean lizard diversity and you think of anoles, dwarf geckos, perhaps curly tailed lizards and whiptails. But skinks don’t generally come to mind. Heck, I almost never see skinks in the Caribbean and, anyway, their diversity is very low, with only six Caribbean species.

Previously considered conspecific

Until now. In a recently published monograph, Hedges and Conn have scrutinized the genus Mabuya, using both molecular and morphological characters, and have more than doubled the number of species, from 26 to 61, which they have broken into 16 genera (and, as a sidenote, they also split the family Scincidae into seven families). That so many species went undetected is perhaps not surprising, in that Mabuya, like most skinks, all look alike, with very few characters available to distinguish them. Moreover, a trend of species lumping has occurred historically, obscuring sometimes great differences among taxa, as illustrated in the photo to the left.

Of the 61 species, 39—in six genera—occur on Caribbean islands. Most occur on a single island, and most islands only have one species, though as many as three occur on Hispaniola and St. Thomas, and two on a number of islands. Oddly, Cuba has none. Like anoles, to which they no doubt aspire,

Read More

Lizards have become a staple of laboratory studies of locomotion. A standard approach, honed to perfection over 30 years of such work, is to get a lizard to run down a narrow trackway or on a dowel to determine how fast it can run and, in recent years via high speed video, to see exactly how the different limb elements move. Questions that one might ask include whether long-legged lizards run faster than their short-legged compatriots, whether species can run faster on broad surfaces as compared to on narrower supports, or whether the loss of a tail affects sprint speed. In fact, the sort of questions one might ask about lizard locomotion are virtually endless.

These studies have one Achilles heel, however, Most such studies focus on examining maximum speed of the lizard, but how can one ensure that lizards are actually running full tilt? The nagging fear has always been that differences in speed might result not for different capabilities, but rather as a result of differential motivation–some lizards just want it more than others.

But how can one elicit maximal speed or investigate whether a lizard is holding back? One approach to this question was revealed in a recent paper in J. Herp. Jones and Jayne tested whether a loud noise might cause a lizard to run faster and the answer is: yes, when subjected to repeated loud noises, lizards in experimental race tracks do, in fact, run faster.

And just what kind of loud noise? Let’s let junior author Bruce Jayne explain the genesis of the study:

Read More