The Grenadines. (http://en.wikipedia.org/wiki/File:Grenadines- Archipelago)
Check out the Grenadines, a polyphyletic chain of approximately 600 islands found at the southern end of the Lesser Antilles. The islands north of the Martinique Channel are governed by St. Vincent. The islands south of the Martinique Channel are governed by Grenada. (Grenada, you’ll recall, was invaded by the US in 1983).
Given Martinique Channel’s apparent role as a political boundary, I wondered if it is also an important biogeographical boundary, much like Wallace’s Line in Indonesia. Wallace’s line, which passes through through the Lombok Strait between Bali and Lombok and between Borneo and Sulawesi, denotes a clear faunal break between Asian and Oceanic faunas. The biogeographical explanation is that Wallace’s line follows the transition from continental shelf to deep water channel, which serves as a barrier for migration.
Martinique Channel (line added).
A look at the Caribherp distribution of herpetofauna found on the Grenadines suggests that the Martinique Channel is not actually a biogeographic break. The distribution of most herps found on the Grenadines crosses the channel, suggesting that the channel is not a barrier to migration. And, consistent with this, Google Earth suggests that the channel is not very deep.
Oh, almost forgot: the Anolis species on the Grenadines are A. aeneus, A. richardi, and the invasive A. sagrei.
Anolis aeneus. Photo from http://www.kingsnake.com/westindian/anolisaeneus5.JPG.
Anolis richardi. (Photo from http://reptile-database.reptarium.cz)
- DNA Sequencing from Formalin-Preserved Specimens - December 16, 2014
- Sans the Claws, Anoles Present Under The Trees? - December 5, 2014
- Out Damned Spot! Or, How They’d Be Loving If They Weren’t Fighting - November 18, 2014
Daniel Scantlebury
Maybe not that effective, but there are still some nice breaks in the area around the line. Gonatodes daudini, only known from Union Island though similar habitat exists on Carriacou (there is hope as Sphaerodactylus kirbyi was recently found on both islands). Also, check out how Grenadine tree boas look as you cross the channel north, on the dry-scrub island Mayreau.
Yoel Stuart
Cool Dan. Good to know. I was wondering if there were any differences subtler than the species level that wouldn’t show up on Caribherp. As you point out, seems like there may be.
Rich Glor
It’s amazing that there are 600 islands in this region. Does anybody know how many are habitable by lizards?