Question

Axolotl larva shows
Neoteny and paedogenesis
Absence of thyroxine affects metamorphosis
It is hemichordata

A. i, ii and iii correct
B. i and ii correct
C. ii and iii correct
D. iii correct

Answer 1

Hint: The Axolotls are popular the name of Mexican salamander because they're the larval variety of Mexican Salamander amphibian (Ambystoma mexicanum) and they are an animal model employed in limb regeneration studies.

Complete answer:
The axolotl salamander undergoes the neoteny, which could be a rare trait found in them of retaining its larval feature throughout its adult life. This means this keeps its tadpole like dorsal fins, which are on almost the length of its body, and the feathery external gills, which project from the back of its wide head.
The Mexican walking fish or Axolotls is a neotenic salamander; they are related to the tiger salamander. Meanwhile, the axolotl is colloquially called a walking fish because it is not a fish, but an amphibian. An axolotl shows neoteny, which means that they reach sexual maturity without undergoing metamorphosis.
In the axolotl, lack of thyroid stimulating hormone, which is induced by thyroid to produce thyroxine, leads to the metamorphic failure in transforming salamanders.
Because of Its healing ability, it features a salamander that draws the foremost attention. The axolotl does not go through healing by scarring but they are capable of the regeneration of entire lost appendages in a period of months (paedogenesis). In some cases, they have been known to repair a damaged limb, also regenerating an additional one, and finish with an additional appendage.
The correct answer is B (Neoteny and paedogenesis)
Axolotls reach sexual maturity in about 12 months; a male releases spermatophore in water and females may take them up and end with laying of 200-600 eggs on plants. The development of egg takes place in two weeks and after that the tadpole remains attached to the plant for two weeks. Loss or amputation of the axolotl limb leads to the regeneration of the lost limb from trunk tissue, so that they repeat developmental sequences as a repair process.


Note: Axolotls have long lives and they can survive up to 15 years and on the feeding of mollusks, worms, insects, larvae, crustaceans, and some small fish. They are mainly found in the lake complex of Xochimilco, near Mexico City, and also differ from most other salamanders which live permanently in water.