Abstract: The paper deals with a new form of Sinoadapis from the Lufeng hominoid Locality, assigned to Sinoadapis shihuibaensis sp. nov. .
Holotype
PA 882 A fragment of right mandible with C, —M3.
Other materials
PA 903 A fragment of left maxilla with P3—M3.
PA 959 Left lower tooth row with I1—P2, P4.
PA 902 Right upper tooth row with C'-p3.
PA 964 An isolated left I1. PA 907 An isolated right I2.
PA 972 An isolated right M3.
In comparison with Sinoadapis carnosus the new species shows the following features: relatively slender mandible with narrower cheek teeth, sharper cusps, larger trigonid fovea, developed buccal cingulum and larger upper and lower canines. The hypoconulid is elongated posteriorly and is separated from the entoconid by a deep notch. The buccalingual diameters of upper molars are slightly smaller and the lingual cingula are rather developed. The metaconid is relatively reduced in M3 and the metacone located relatively closer to the protocone.
Sinoadapis differs from Sivaladapis principally in its larger size and the P4 highly molarised and longer than any molar of the same individual. A series of upper and lower dentitions of Sinoadapis shihuibaensis were preserved. Sinoadapis shihuibaensis is basically similar to that of Sivaladapis nagri described by Gingerich. However, it also differs from Sivaladapis nagrii in some characters. The lingual cingula incompletely enelose the protocone in upper fourth premolar and upper molars and there are no enamel folds in the lingual wall of the protocone. The upper and lower third prenolars are narrower? Both the trigonid and the talonid in P4 are enlarged and the large pro- toeone located more forward than the metaconid. There are clear demarcations between the cusps, but no the enamel folds on the lingual surface. The lower molars have large trigonid fovea. The notch between the hypoconulid and the entoconid is not as deep as Sivaladapis nagrü, while the cusps of Siraladapis nagri are sharper than that of Sinoadapis shihuibaensis.
Adapid primates of Lufeng are more abundant than those of both India and Pakistan and the species frum Lufeng seems to be more complex. It indicates that there is probably a major radiation of Mioeenp adapids in Lufeng. Sinoadapis of Lufeng elearly differs from both Indraloris and Siralapis from the Siwaliks of India and Pakistan. Judging from the Lufeng mammalian fauna, Lufeng hominoid site is younger in age than Nagri beds near Haritalyangar of India. The Lufeng speeies provides important. fossil evidence for the understandinr of Miocene Adapids.

Key words: Sinoadapis shihuibaensis; Latest Miocene; Lufeng