On a Dog Skull of Stone Age in Japan and its Ancestral Form

Abstract

Basing upon the measurements of about one hundred pieces of skulls and mandibles from several neolithic shell mounds in different parts of Japan and more than three hundreds of those from younger dated shell mounds and dwelling pits in Hokkaido, Kurile and Saghalin, the author classifies the prehistoric dogs into the following five kinds by the total skull length : X-155, 156-170, 171-185, 186-200 and 201-Xmm. The prehistoric dog races, Canis familiaris palustris, ladogensis, intermedius, inostranzewii and matris optimae, fall in the assigned classes respectively in the order. The dogs from neolithic shell mounds agree in more than 50% of the cases with the palustris, with a little more frequency with the ladogensis and rarely with the intermedius, while no trace of the inostranzewii and matris optimae is pointed out. A dog of the same size as the inostranzewii camel out sometimes from prehistoric sites in Asia, for instance in Anau, Mohenjo-Darn, Anyang *c, but such as matris optimae has sofar remained unknown. However, the latter is observed not seldom at the shell mounds on the coast of the Ochotk Sea.
Recently the author received with surprise a dog skull of such a size as that of the matris optimae. It was found at the shell mounds of Kamikawana in Tsukinokimachi, Shiba District, Miyagi Prefecture. This is suggested by its owner to be that of a japanese wolf, Canis hodophylax, but has a more broad upper face and jaw, shorter muzzle and shorter lower first molar too h, as the following table shows. It is well plausible, that the dog or its nearest ancestor should have been imported over the Tsugaru channel from Hokkaido.
In the total length of the skull, the matris optimae is to be compared with the asiatic wolves, Canis pallipes and hodophylax, the intermedius with the african jackal, C. lupaster, the ladogensis with the american coyote, C. latrans and the palustris with the asiatic jackal, C. aureus. These dog races are characterized in general by the broadness of the face and the shortness of the muzzle for the size of the head. Most striking difference between the dogs and wolves is the weakness of the teeth in the former. But things appear to be quite different with the matris optimae and the Canis variabilis Pei from the Sinanthropus site. The length of the lower first molar tooth of the C. variabilis is over 25mm in a fourth and 21-24mm in three fourth of the cases. While that of the matris optimae amounts to 20-24mm and that of the C. hodophylax to 25mm or more. A few portion of the examined mandibles of the lower pleistocen wolf is of the same size as the inostranzewii. The author supposes that the Canis variabilis inhabited at that time in a large area in southern Asia and afterwards is differentiated to the Canis pallipes, hodophylax, fam. matris optimae and fam. inostranzewii. Therefor the living wolf kinds have nothing to do with the ancestral forms of the prehistoric dog races.