April 10, 2008

Lungless frog: “A squished version of Jabba the Hutt” that has reversed evolution

Posted by pleasecroak under lungless, medical research | Tags: , , , , , , , , , , , , |
[2] Comments 

Image from Wikipedia

One of the discoverers of the lungless frog on Borneo in Indonesia says in an Associated Press story that the Barbourula kalimantanensis looks “like a squished version of Jabba the Hutt.” So, Star Wars fans, you decide! Excerpt from the story:

“These are about the most ancient and bizarre frogs you can get on the planet,” (biologist David) Bickford said of the brown amphibian with bulging eyes and a tendency to flatten itself as it glides across the water.

“They are like a squished version of Jabba the Hutt,” he said, referring to the character from Star Wars. “They are flat and have eyes that float above the water. They have skin flaps coming off their arms and legs.”

A helpful explanation from the latest story I’ve come across:

While many frogs breathe partially through their skin, the Barbourula kalimantanensis is the first to have entirely evolved away from having lungs … This runs counter to one of the key events in evolution, when animals developed primitive lungs and moved from water to land.

“Here is a frog that has reversed that trend, it has totally turned against the conventional wisdom, if you will, of millions of years of evolution,” said Bickford, a biologist at the National University of Singapore.

The frog appears to have shed its lungs over millions of years to adapt to its home in the fast-flowing cold water rivers in the island’s rainforests, Bickford said.

Cold water contains more oxygen, making it possible to breathe through skin, he added.

New to the amphibian crisis? Learn more here.

 

April 8, 2008

Lungless frog — now how did that happen?

Posted by pleasecroak under Uncategorized | Tags: , , , , , , |
Leave a Comment 

We talk all the time about amphibians breathing through their skin, and continually evolving. So it’s not completely a shocker that in Borneo scientists have found the first frog species that is lungless. It’s the Barbourula kalimantanensis. Here’s the article.

So how did this happen? Here’s excerpt from ITWire:

Scientists currently are leaning toward that theory that the frog once had lungs long time ago but had difficulties going from the surface to the bottom of fast-moving water in cold streams because of the buoyancy of air-filled lungs.

Thus, the frogs slowly evolved from breathing through lungs to breathing through their skin, and eliminated the presence of lungs in their bodies.

Scientists already know that amphibians rarely breathe through their skin because it is more difficult to get sufficient oxygen into their bodies than with the process of breathing through lungs.

Only cold-blooded animals breathe through their skins because they don’t move as much, so do not expend as much oxygen.

The scientific community knows of only one family of salamanders and one species of caecilians that are lungless amphibians, besides B. kalimantanensis.

For the lungless frog whose habitat includes cold water, the low temperatures of its water holds more oxygen than warm waters, which is desirable. Plus, rapidly flowing streams allow more oxygen to flow over the body of the lungless frogs than slowly moving streams, which is also beneficial for the frogs.

So, with its habitat being clear, cold, fast-flowing streams, the lungless frogs are very happy living in such streams in Borneo.