THE LOGGERHEAD TURTLES IN JAPAN AND NEIGHBORING WATERS (TESTUDINATA : CHELONIIDAE)

Abstract

There have been some confusions in the taxonomy and nomenclature of the loggerhead turtles occurring in the Japanese and adjacent waters. Most of previous authors regarded the population of the turtles found or caught in Japan and her adjoining waters as consisting of a single species, and applied to it the name Caretta olivacea (EscHSCHOLTZ) or Caretta caretta olivacea (EscHSCHOLTZ) (STEJNEGER 1907; TAYLOR 1921; OKADA 1927, 1938, 1947; TAKASHIMA 1932; PoPE 1935; HIRASAKA 1943; UTINOMI 1943; NAKAMURA 1957; HoTTA 1960; etc.) These authors were, however, not right in two points: first they were not aware of the existence of two distinct species in the populations of the Japanese loggerhead species, and secondly some of them failed to find the correct scientific name for the commoner one generally known by the Japanese name 'aka-umigame' (aka means red, umigame means sea turtle). For the first time in 1963, NAKAMURA and U:ENo revealed that the loggerhead turtles caught in the Japanese waters consist really of two distinct species belonging to the two different genera and designated them respectively as Caretta caretta gigas DERANIYAGALA and Lepidochelys olivacea olivacea (EscHSCHOLTz). Though the distinction and the descriptions of the two species by these authors were made properly, for some unknown reason the two scientific names were assigned to erroneously; i.e., Lepidochelys olivacea olivacea was applied to the true Caretta caretta (red-brown loggerhead in English; aka-umigame in Japanese) and Caretta caretta gigas was applied to the real Lepidochelys olivacea (Pacific ridley or olive loggerhead in English; hime-umigame in Japanese) ( cf. NISHIMURA & HARA 1967).