Sword Tail Newt, Cynops ensicuada

The Sword-tail Newt (Cynops ensicauda) has recently been put on Japan’s Red List of Threatened Amphibians. This newt has a very small range and can only be found in some of the southernmost islands in Japan. Occasionally, Sword-tail Newts are referred to as Fire-bellied Newts, not to be confused with the common Chinese and Japanese species, because of their bright orange colored bellies, which serve as a warning to predators that they are poisonous. They can be distinguished from these two species by their large size, broader heads and smoother skin. This newt ranges from brown to black above, sometimes with an orange dorsal stripe. Some individuals have light spotting or speckling featured on their backs.

These newts grow from 5 to 7 inches and are considered to be the largest living members of their genus. The females and the males look drastically different in appearance. The females have much longer tails that are actually longer than their bodies. The males’ tails are much shorter and occasionally display a whitish sheen during the breeding season.

The Sword-tailed Newt can only be found in the Ryukyu Archipelago, an island chain off of the southern coast of Japan, as well as on many other smaller surrounding islands. This newt’s habitat is slow, cool, and stagnant bodies of water. They are commonly found in man-made structures such as rice paddies, road-side ditches, and cattle waterholes. The two known subspecies of Sword-tailed Newt are C. e. ensicauda and C. e. popei. Because of the subtropical climate of this native habitat, it is more tolerant of high temperatures than other Cynops. It has no predators, so deforestation and land development are the main causes of their endangerment.

Breeding places are being frequented by only a fourth of the population that was breeding fourteen years ago. This lack of breeding is another key reason for them becoming endangered. Many of their breeding places are in roadside ditches and gutters, which can lead to them being run over. They are extremely territorial; therefore moving their breeding places would be difficult.

Image Caption: Cynops ensicauda popei. Credit: J-Moss/Wikipedia (CC BY-SA 3.0)