1975 Volume 6 Issue 3 Pages 127-136
Lutronectes whiteleyi GRAY, 1867, based on two young specimens collected from Hakodate, Hokkaido, Japan, seems to be extinct in the native land, and no specimens have been known in Japan.
While studying the river otter of Japan, the author was attracted his attention by an adult rough skeleton of the subgenus Lutra in the mammal collection of the National Science Museum, Tokyo. Unfortunately the locality of the specimen is uncertain, but there is little doubt that it was collected at the beginning of the Mei ji era, nearly 100 years ago, in the territory of Japan at that time, that is Hondo or Hokkaido. As the specimen is evidently different from the otter of Hondo, the locality is inevitably estimated as Hokkaido.
This estimation coincides with the result of identification of the specimen as Lutra whiteleyi based on strong similarities to OGNEV's adult specimen from Nemuro, Hokkaido, and dissimilarities to the most of the named forms of the subgenus Lutra, in several cranial measurements.
If this identification is correct, whiteleyi seems to be a well established taxon of Lutra lutra group characterized by relatively narrow mastoid breadth and shorter muzzle (Table 6, F and G) .
An opinion that whiteleyi covers whole populations of the Japanese otter, proposed by Pococx (1931), the present author (1949), etc., is not correct. L. whiteleyi must be confined to the Hokkaido population.