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.
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.