Recent discovery of old specimens of a rare lampray Lenthenteron sp. collected from the Shigenobu River-system in Ehime Prefecture

A rare lampray Lenthenteron sp. (Agnatha: Petromyzontidae) was considered to already extinct in the Ehime Prefecture of the Shikoku Island (Japan). Previous records and recent personal comments exhibited that the species was widely distributed in the Dozen and Matsuyama Plains of Ehime Prefecture, although the officially preserved specimens of the species were limited in a few collections. I discovered additional six specimens of the species (three young and three adult fishes) into a collection lot that kept in a public school of Ehime Prefecture. The specimens were collected from the Ishite and Ono rivers of the Shigenobu River-system in September 1950, possibly indicate the oldest record of the specimen from the Matsuyama Plain. I here describe a detail of the specimens, and give a supposition to ancient status of the species inhabitant in Ehime prefecture based on information of the specimens discovered in this study and related other specimens collected from the Matsuyama Plain.