Pet Amphibians Are Part of a Diverse Species

The more than 4,000 species that make up the “Amphibia class” are incredibly diverse. They exhibit every color you can imagine, and have distinctive characteristics that range from leaping frogs to slithery newts. Having an amphibian as a pet is having a conqueror – they were the first of the animals with backbones (the vertebrates) to make the transition from water to land.  The  amphibians species is something special.

These animals might be the smallest of the vertebrates, but they used to roam the world like they owned it! That pet frog in your hand is one of man’s most important evolutionary steps.

The Amphibia class is made up of three orders:

• Anura (frogs, toads)
• Urodela (salamanders, newts, sirens)
• Gymnophiona (caecilians)

The anura are made up of 3,094 species, the urodela 358, and the gymnphiona 163. That’s a lot of potential pet amphibians, but of course not all adapt as well to captivity as others, or indeed are as available.

Your Pet Amphibians Are Pioneers!
360 million years ago the Devonian deposits of Australia, and the freshwater beds of Greenland, saw the beginnings of the Amphibia. The Crossopterygii order of fish had bony fins, and it is probable that these fish are the ancestors of your pet amphibians. Crossopterygians also had lungs, and nostrils that allowed them to take in air from above water. These internal fish nostrils are known as nares, and were also found on the Ichthyostega of America and Europe. In addition the lungs and nares they also had an anterior and posterior brain. Although still fish-like in many ways these Ichthyostega were amongst the first amphibians.

So how did the amphibians make the leap from water to land? Traditional theory postulates that as ponds dried up fish were forced to slither across land to the next available water deposit. However, there evidence that the Devonian period was pretty tropical so this theory doesn’t really stand up.

An alternative, and more exciting theory, is that amphibians evolved as enhanced predators. The functional neck of the amphibian likely developed in fish that wanted to suddenly switch direction to grab prey, and it was this evolutionary step that facilitated the move to land. But why did these aquatic predators switch to becoming terrestrial?

Some possible explanations are:

• with all the competition for prey in the water, land provided a safe haven for laying eggs
• the water shall water pools were poorly oxygenated, thus encouraging the development of lungs to breath on land
• an abundance of tasty insects on land

These developments took place over millions of years, and fossils provide no clear answers. Some even suggest that the transition from fish to amphibian may have happened more than once. One thing can say is that the amphibians species are a key part of evolution.

Click for more on all kinds of amphibians.