作者：宗冠福

摘要： A complete right third lower molar from Pingliang, Kannsu represents a new species of Pentalophodon. (V 5836) From the first to fifth ridges the pretrites and posttrites were worn after chewing and the enamel was broken at both the labial and lingual sides of the first two ridges and lingual side of fifth ridge, while the remaining ones are still fresh. Exact horizon unknown, probably of upper Pliocene or Lower Pleistocene.
    Specific characters: Third lower molar is unusually long and narrow, and consists of seven transverse ridges or lophs. The crown of the tooth is subhypsodont. Pretrites and posttrites, except the sixth and seventh ridges, are arranged in alternating series. All trites are thick or stout, and the transverse valleys are very narrow; above all in the lingual side, the pretrite is almost connected with the next pretrite. The pretrites and posttrites almost vertically to the long axis of the tooth. Cingula not developed and cement not too abundantly present on the bottom of transverse valleys.
Judging from the structure and the number of ridges and the exceeding length of the third lower molar, Pentalophodon pingliangensis is a rather advanced form of brevirostrine mastodonts.

卷期：17卷 01期

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