A newt is an aquatic amphibian of the family Salamandridae, although not all aquatic salamanders are considered newts. Newts are classified in the subfamily Pleurodelinae of the family Salamandridae, and are found in North America, Europe and Asia.
Newts metamorphose through three distinct developmental life stages: aquatic larva, terrestrial juvenile and adult. Adult newts have lizard-like bodies and may be either fully aquatic, living permanently in the water, or semi-aquatic, living terrestrially but returning to the water each year to breed.
Newts share many of the characteristics of their salamander kin; Caudata, including semi-permeable glandular skin, four equal sized limbs and a distinct tail. The newt’s skin, however, is not as smooth as that of other salamanders. Aquatic larvae have true teeth on both upper and lower jaws, and external gills. They have the ability to regenerate limbs, eyes, spinal cords, hearts, intestines, and upper and lower jaws.
Recently it was discovered that the Japanese fire belly newt can regenerate its eye lens 18 times over a period of 16 years and retain its structural and functional properties. The cells at the site of the injury have the ability to de-differentiate, reproduce rapidly, and differentiate again to create a new limb or organ. One theory is that the de-differentiated cells are related to tumour cells since chemicals which produce tumours in other animals will produce additional limbs in newts.
Title: Joint issue of Belarus and Russia – Newts
Date of Issue: 25 June 2012
Denominations: H, P