The Adaptation of a Water - only Living Amphibian

The adaptation of a water-only living amphibian

Vertebrate Biology

2047

October 21, 2014

The adaptation of a water-only living amphibian

Name: Axolotl

Class: Amphibia

Order: Urodela

Family: Ambystomatidae

Genus: Ambystoma

Scientific Name: Ambystoma mexicanum

Mexican axolotls, Ambystoma mexicanum, are vertebrate animals that belong to the Class Amphibia. The majority of animals that are part of this Class are known for having a double life that involves a stage in water and a stage on land. Axolotls, however, are one of the few exceptions to the rule. These salamanders are known as neotenous species, which means that they retain their larva form into adulthood and become sexually mature during their larval stages, keeping their gills and tails. This adaptation makes it impossible for them to survive on a land habitat.

Being an amphibian with a water-only environmental condition has some evolutionary disadvantages, such as less opportunities to colonize new habitats, but at the same time it helps them to be more successful in their native territory. Due to their non-metamorphic characteristic, axolotls are very successful at reaching their maturity in shorter periods of time. It usually takes them 10 to 15 months as opposed to land animals that may take two years or more to reach it.

Axolotls are known as the Mexican fish due to the place where they were first found, in the lakes Chalco and Xochimilco of the Valley of Mexico, in Mexico. These animals play a big role in their habitat since they are the biggest predators within it. However, they are now nearly extinct due mostly to the introduction of predatory fishes and habitat changes, such as the loss of floating vegetation which is vital for their reproductive process in safely hiding their eggs.

This salamander variety sustain a meat based diet. They usually feed on worms, insects, and small fish. Due to the type of teeth they possess, called pedicellate which are designed more to grip rather than to bite (see image 1), they are not able to rip their prey and so their food must be small enough to be able to fit in their mouths. However, these amphibians do use their teeth to maneuver their prey into position before swallowing it completely.

Like any other amphibians, axolotls have a three-chambered heart. The design of this type of heart is one of the components that helps the members of this Class to breathe through their skin, gills, or lungs according to the environment they are in, be it aquatic or terrestrial. As mentioned earlier, axolotls