|Scientific Name:||Opisthotropis kikuzatoi (Okada & Takara, 1958)|
Liopeltis kikuzatoi Okada & Takara, 1958
|Red List Category & Criteria:||Critically Endangered B1ab(iii,v)+2ab(iii,v) ver 3.1|
|Assessor(s):||Kidera, N. & Ota, H.|
Opisthotropics kikuzatoi is endemic to Kumejima Island. The area of occupancy is estimated to be less than 10 km2, there is an ongoing decline in the extent and quality of its habitat and in the number of mature individuals. This species occurs as two completely isolated subpopulations, at least one of which is unlikely to be viable and shows some evidence of genetic problems, and is considered to occur as a severely fragmented population. The species is listed as Critically Endangered.
|Previously published Red List assessments:|
Opisthotropis kikuzatoi is endemic to Kumejima Island, one of the Okinawa Group islands in Japan. Its distribution is restricted to two hilly areas located in the northern and the southern parts of the Island. The total area of occupancy is approximately 10 km2. The intervening area has been completely converted to cultivated lands and residential areas (Ota 2014).
|Range Map:||Click here to open the map viewer and explore range.|
This is a rare species. The frequency of occurrence has dropped to one tenth in fifteen years after 1983 in one of the two localities (Ota 2014). There is no information on the status of the other subpopulation (Ota 2014), but it is presumably in decline.
|Current Population Trend:||Decreasing|
|Habitat and Ecology:|
This species occurs in permanent streams along broadleaved evergreen forests. Its habitat is a highly specific environment which experiences no drought, offers sufficient food resources such as freshwater crabs and shade vegetation to avoiding direct sunlight (Ota 2014). This habitat remains only in a very restricted part of Kumejima.
|Continuing decline in area, extent and/or quality of habitat:||Yes|
|Movement patterns:||Not a Migrant|
|Use and Trade:||There is no information on any use of or trade in this species.|
The major threats are water pollution, incidental capture as bycatch, and predation by introduced bull frog. The cause of water pollution is unclear. The bullfrog (Lithobates catesbeianus) has been introduced to Kumejima Island in 1953; this may result in high predation pressure to which this snake may be especially sensitive following drastic declines over the last 15 years. It is likely that the population is undergoing a decline of genetic diversity due to inbreeding, as the two subpopulations are completely isolated from one another and at least one now appears to be very small. Individuals with asymmetrical scales on their heads are often observed (Ota 2014).
Opisthotropis kikuzatoi is categorized as a National Endangered Species of Wild Fauna and Flora under the Act on Conservation of Endangered Species of Wild Fauna and Flora, as well as a natural monument in Okinawa. Capture is forbidden. The middle and northern area in the island was assigned as Natural Habitat Protection Area by Environment Agency of Japan in 1998 (Ota 2014).
|Citation:||Kidera, N. & Ota, H. 2017. Opisthotropis kikuzatoi. The IUCN Red List of Threatened Species 2017: e.T15391A96877390.Downloaded on 22 July 2018.|
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