1. Axolotl is the larva of Ambystoma tigrinum. It was previously supposed as an adult form called Siredon.
2. It possesses three pairs of external gills and four pairs of gill-clefts. Tail with caudal fin.
3. Head has eyes, nostrils and mouth. Forelimbs and hindlimbs present.
4. Axolotl larva is a perennial form and develops gonads (sexually mature) and, thus, exhibits the phenomena of neoteny (failure to metamorphose because of environmental conditions).
5. When environmental conditions such as low temperature, abundance of nutrition and oxygen supply and lack of iodine in water inhibit the action of thyroid gland, the axolotl larva becomes sexually mature and reproduces like adult Ambystoma.
6. If the environmental conditions are changed, it is capable of metamorphosing.
7. Metamorphosis in Axolotl can also be induced by injecting thyroid extract or by transferring to water with a higher iodine content.
8. During metamorphosis, the gills and tail fin are lost.
Source:
1. Practical Zoology Vertebrates by S.S.Lal. 2. A Manual of Practical Zoology Chordates by Dr. P.S. Verma.
