Abstract: The specimen of Lophochoerus described here was collected at Sivapithecus (Ba- mapithecus) site., Lufeng county, Yunnan Province in 1981. It includes almost all left lower cheek teeth, except the first lower molar, and a fragment of the anterior part of right mandibule with P1 and a lower canine. Judging from the characters of the molars it belongs to the Lophochoerus.
This pig is of small size. The premolars possess high main cusps, and P4 is not coni_x001F_cal. On the contrary, its width is comparatively narrow and the posterior ridge of main cusps of P3 and P4 separates into two branches. The talonid tapers anteriorly and blocks the medium valley of P3. The outside branch connects with talonid of P4. Pi, P2, P3 and the front part of P4 have no contact facets. This may be due to the existence of little diastema between each of them. The cusps of molars are comparatively simple. M： is absent, M2 is broken, but it seems to be slightly longer than P4'. Lingual cusps of M(3 are conical, separated down to the basal part of the crown. Labial cusps are somewhat V shaped, the anterior arms of which extend to the anterior cingulum and the first transverse eresting respectively. A slightly longer anterior ridge runs from the talonid to the second transverse cresting.
From the characters of the pig described above, it is quite obvious that the Lufeng form {Lophochoerus lufengen^is sp. nov.) differs from that species of Lophochoerus of Siwalik in： 1) ra.ther larger in size; 2) M2 slightly longer than P4; 3) posterior structure of P3 and P4 and 4) the structure of talonid of M3.
Lophochoerus is a pig which occurred in Lower and Middle Siwalik in India, But now it is also found in lignite beds of Miocene in Yunnan Province. Whether that species of India is in fact ancestral to Lophochoerus lu.fengensis sp. nov. remains to be seen.

Key words: Miocene Sivapithecus (Ramapithecus) fauna; Artiodaetyla; Lopho-choerus