Category: Notes from the Field Page 21 of 22

Alexis Harrison and I have spent the last two days on Grand Cayman collecting tail tips from Anolis sagrei. During our work, we’ve seen quite a few A. conspersus. Anolis conspersus is nested within the Jamaican A. grahami, splitting away approximately 2.5 to 3 million years ago when it colonized Grand Cayman. Both species vary in body color across their range from brown to drab green to emerald green to blue green with white mottling.

They are very different, however, in the dewlap. Anolis grahami’s dewlap reflects strongly in the long wavelengths, being orange with a yellow margin. The dewlap of A. conspersus, on the other hand, reflects in short wavelengths being blue and UV-bright.

Anolis grahami - Jamaica

Anolis conspersus - Grand Cayman

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Over the last half-century, Anolis sagrei sagrei, a Cuban native, has become a global citizen. Likely as a stowaway in agricultural trade shipments, it has traveled to near-Cuba places like Florida, Jamaica, and Grand Cayman. It has gone as far Hawaii, Guam, and Taiwan. It is a stout lizard, males about 60mm long, brown in body color with a deep red dewlap bordered by a yellow margin. Jason Kolbe’s research documented the origin and spread of invasive populations of this subspecies around the globe.

Another subspecies of A. sagrei, A. sagrei luteosignifer, is endemic to Cayman Brac, the easternmost of the three Cayman Islands islands. On Brac, A. s. luteosignifer has evolved a mustard-yellow dewlap, in stark contrast to the red dewlap of A. s. sagrei.

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I had a bit of free time to take photos along the Recodo Road this afternoon and managed to get a few nice shots of Anolis marcanoi and its spectacular dewlap. Anolis marcanoi was among the first anoles to be described with the aid of genetic data, with early electrophoretic work being used to confirm that it was genetically distinct from sympatrically distributed populations of A. cybotes that have white or pale yellow dewlaps (Webster 1975, Williams 1975 [they’re a bit of a pain to access, but both articles are available via the Biodiversity Heritage Library]). Although they were initially regarded as ‘sibling species,’ subsequent phylogenetic work suggests that A. marcanoi is in fact the outgroup to all remaining species of cybotoid anoles (A. cybotes, A. longitibialis, A. strahmi, A. breslini, A. whitemani, A. shrevei, and A. armouri). Interactions between A. marcanoi and A. cybotes were also the subject of Losos’s (1985) famous ‘lipstick’ study in which “True Red” lipstick was used to experimentally render the dewlaps of A. cybotes a similar hue to those of A. cybotes (A. marcanoi males, in turn, had their dewlaps painted white with “Superior Clown White Make Up” to make them look like A. cybotes). This study remains one of the only investigations to date to address the role of the dewlap in species-recognition.  We have our last day of work in the field tomorrow before heading back to snowy Rochester!

If you love anoles and have visited the Dominican Republic, chances are that you’ve spent some time on the Recodo Road.  Initially made famous by Ernest Williams and his students, this road running north of Bani into the foothills of the Cordillera Central remains one of the most interesting anole hunting localities in the DR.  My lab is particularly interested in the interactions between three types of trunk anoles in this region: Anolis brevirostris, A. distichus ignigularis, and A. distichus ravitergum (we’ve recently suggested that the latter two may deserve elevation to full species status and Luke covered this topic in a previous blog post).  We’re currently using molecular genetic and ecological methods to investigate the possibility of ecological speciation among these forms.

I thought it would be fun to share some recent developments along this classic anole hunting locality.  One feature of the Recodo Road that is both a blessing and a curse is the need to cross the Rio Baní.  Because there are no bridges, crossing the river requires driving through the river itself.  This generally isn’t a problem with a good 4×4, but getting stuck in the middle of the river is somewhat of a right of passage (the route can also be completely impassable after heavy rains).  Shabby bridges made of sticks are often constructed for pedestrians and motorcycles, but these tend to be somewhat shaky and wash out each time the river floods.  This winter, we found that some local entrepreneurs have constructed a somewhat more substantial stick bridge and have been charging a modest toll to motorcyclists interested in using it.  The photo on the left of the image above depicts the toll collector and his modest gate.  We were told that motorcycles were asked to donate what they could, rather than being charged a fixed rate.  The photo on the right of the above image shows where we cross in our 4×4.