Friday, December 12, 2008

An endemic vertebrate

El Salvador is a small country. With 5.7 million inhabitants, it is the most densely populated country in Central America, and large parts of it are cultivated. Original remaining habitats here are more scattered and smaller-scaled than for example in Costa Rica.

But El Salvador appears to have at least one endemic vertebrate. It’s a fish. Recently described as sufficiently distinct to be its own species, it lives in Lake Coatepeque, and yesterday I joined a team of biologists from SalvaNatura to look for it.

This fish, Amatitlania coatepeque, is part of a family known as ‘convict cychlids’, so named for their stripey appearance, similar to prison uniforms.

We didn’t actually find the fish, but we found a fisherman who described it to us in quite some detail – it sounded very much like he knew our fish. He also told us that they normally don’t fish for it. It is too small, and when caught gets thrown back. Good news for this fish, which lives nowhere else in the world but in this lake.

His wife made lunch for us: fried fish, caught that morning from the lake. It wasn’t our fish. It was a bigger fish, tilapia, an exotic.

Besides the fish, we also looked for a butterfly, Chlosyne lacinia, or Bordered Patch. Tim, one of my companions yesterday, is studying this fairly common species with a large distribution, all the way from Arizona down to Costa Rica. Since it ranges so widely, it is quite flexible in its selection of host plants and is found in a variety of habitats.

I remember it was quite common last June in the Mexican state of Morelos. Yesterday, we found just this one.

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