Cynops ensicauda has a snout-to-vent length of 53-77 mm and a total length of 103-179 mm. Its dorsal surfaces are generally black or very dark brown and its ventral surface is orangish red. The soles of its feet are the same color as its belly. Some individuals may have stripes or splotches of the ventral color on the back or head. Many individuals, especially those living in sunny locations, have lichenlike blotches here and there on the back and tail. The significance of these blotches is controversial, as they can disappear if the animal is kept in captivity under conditions of low light (Goris and Maeda 2004).
C. ensicauda is similar in appearance to C. pyrrhogaster but C. ensicauda is somewhat larger and has a longer, more slender tail. C. ensicauda can also be distinguished by the light color on the soles of its feet (Goris and Maeda 2004).
Distribution and Habitat
Cynops ensicauda occurs on most of the islands of the Amami and Okinawa Archipelagos, but is not found further south. This species is partially terrestrial, living inconspicuously under leaf litter in both lowland and mountainous forests. However, adults frequently enter the water, especially in search of food (Goris and Maeda 2004).
Catalog Number: USNM 7410
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Amphibians & Reptiles
Year Collected: 1855
Locality: Ousima (= Amami-O-Shima), Amami-O-Shima, Amami Island Group, Japan, Ryukyu Islands, Asia
Habitat and Ecology
Life History and Behavior
Lifespan, longevity, and ageing
Molecular Biology and Genetics
Barcode data: Cynops ensicauda
Below is the sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.
See the BOLD taxonomy browser for more complete information about this specimen.
Other sequences that do not yet meet barcode criteria may also be available.
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Statistics of barcoding coverage: Cynops ensicauda
Public Records: 1
Specimens with Barcodes: 1
Species With Barcodes: 1
IUCN Red List Assessment
Red List Category
Red List Criteria
Life History, Abundance, Activity, and Special Behaviors
Cynops ensicauda has a fairly long breeding season. Depending on rainfall, the season may start as early as October-November and continue until June of the following year, with a peak in January-March. When a rain shower starts, the animals migrate to a suitable body of water, which may be a large pond, a rice paddy, a slow stream, a swamp, or a large ephemeral puddle, but is always in or close to a forest. Males arrive first, then the females. Courtship and spermatophore retrieval is essentially similar to that seen in C. pyrrhogaster but with a lower success rate. There are always many more males than females, all vying for a mate and constantly interrupting the nuptial dance so that the rate of successful spermatophore retrieval is very low: it has been estimated at 2%. Eggs are laid singly in folded-over underwater vegetation, as in C. pyrrhogaster. When the breeding aggregation is dense, the females may lay their eggs at the water's edge or even in mosses outside the water. The eggs are frequently eaten by other newts, especially in the water, and by the snake Amphiesma pryeri. After hatching, only a tiny percentage of the larvae survive to metamorphosis. They are preyed upon by dragonfly larvae and by the larvae of the newt Tylototriton andersoni and are cannibalized by other larvae of their own species. Weather also plays a role in the low survival rate of larvae. Most of the breeding sites are ephemeral. If rainfall is insufficient, the ponds, paddies, and puddles dry up, and a whole season's cohort of larvae perishes. Larvae that survive will metamorphose in about 3 months.
Little is known of the life of this species after metamorphosis. On land it eats the eggs of the newt T. andersoni, snails, slugs, earthworms, and probably small insects. In the water it eats frog tadpoles, its own larvae and those of T. andersoni, snails, tubifex worms, etc. Adults can secrete a noxious poisonous substance from the skin. At such times, they may assume a coiled defense posture with the eyes tightly shut (Goris and Maeda 2004).
Life History, Abundance, Activity, and Special Behaviors
The once-teeming populations of C. ensicauda have declined alarmingly in recent years. There has been massive habit destruction, especially of breeding sites, because of land development. Large, voracious fish of the genus Tilapia have been introduced into traditional breeding ponds. Even where supposedly suitable forest habitat has been preserved, the construction of access roads with concrete drainage ditches often proves fatal. The animals wander about to forage on rainy days and tumble into the ditches, where they are baked by the sun when the rain ceases (Goris and Maeda 2004).
Chytridiomycosis may be a threat to this species. Wild C. ensicauda were found to have a relatively high prevalence of Batrachochytrium dendrobatidis (Bd), with 12 of 24 sampled animals (50%) positive for Bd (Goka et al. 2009). Four Bd haplotypes were found on C. ensicauda (haplotypes A, E, I, and W) (Goka et al. 2009).
Relevance to Humans and Ecosystems
Relation to Humans
Cynops ensicauda has been collected by the tens of thousands for the pet trade. Most of these animals perish because they are sold and treated as aquatic animals, whereas in actuality they are partially terrestrial (Goris and Maeda 2004).
The sword-tail newt (Cynops ensicauda) has recently been placed 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 of Japan. Sometimes, sword-tail newts are called fire-bellied newts, not to be confused with the common Chinese and Japanese species, because of their bright orange bellies, which serve as a warning to predators that they are poisonous. They can be differentiated from these two species by their large size, broader heads and (against Japanese fire-bellies) smoother skin. This newt ranges from brown to black above, occasionally with an orange dorsal stripe. Some individuals may have light spotting or speckling on their backs.
Sword-tailed newts grow from 12 - 18 cm (5 - 7 in) and are considered to be the largest living members of their genus. . Females and males look significantly different in appearance. Females have much longer tails that are actually longer than the rest of their bodies. Males’ tails are much shorter and sometimes display a whitish sheen during breeding season.
Habitat and distribution
The sword-tailed newt is only found on the Ryukyu Archipelago, an island chain of the southern coast of Japan, as well as on many smaller surrounding islands. This newt's habitat is slow, cool, 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. Due to the subtropical climate of its native habitat, it is more tolerant of high temperatures than other Cynops. The sword-tailed newt has no predators, so deforestation and land development are the main reasons for their endangerment.
Breeding places are being frequented by only a fourth of the population that was breeding 14 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. Sword-tail newts are extremely territorial, thus making moving their breeding places difficult.
- "Cynops ensicauda". Amphibian Species of the World 5.5. American Museum of Natural History. http://research.amnh.org/vz/herpetology/amphibia/?action=names&geo=0&taxon=triturus. Retrieved 8 September 2012.
- Caudata Culture Species Entry - Cynops ensicauda
- Kaneko & Matsui (2004). Cynops ensicauda. 2006. IUCN Red List of Threatened Species. IUCN 2006. www.iucnredlist.org. Retrieved on 11 May 2006. Database entry includes a range map and justification for why this species is labeled endangered
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