禄丰古猿地点中国兔猴一新种

A NEW SPECIES OF SINOADAPIS FROM THE HOMINOID SITE, LUFENG

本文记述的是在云南禄丰石灰坝古猿化石产地与古猿共生的一种中国兔猴化石。这类化石以下颌骨和牙齿较纤细,牙齿的颊侧齿带较发育,牙齿狭长,齿尖锐利和臼齿咬合面的三角凹较大,下次小尖向后延伸而使下内尖和下次小尖之间有较大间隔;上臼齿的颊舌径较小等特征区别于中国兔猴厚齿种(Sinoadapis carnosus Wu and Pan.)根据以上的形态特征,作者把它订为中国兔猴一新种:中国兔猴石灰坝种Sinoadapis shihuibaensis sp.nov.。

The paper deals with a new form of Sinoadapis from the Lufeng hominoid Loca-lity, 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'桺3. 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 featu-res : relatively slender mandible with narrower cheek teeth, sharper cusps, larger tri-gonid fovea, developed buccal cingulum and larger upper and lower canines. The hy-poconulid 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 lo-cated 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 Sinoad-apis shihuibaensis were preserved. Sinoadapis shihuibaensis is basically similar to that of Sivaladapis nagrii described by Gingerich. However, it also differs from Sivaladapis nagrii in some characters. The lingual cingula incomple-tely enclose 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 premolars are narrower Both the trigonid and the talonid in P4 are enlarged and the large pro-tocone 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 nagrii, while the cusps of Sivaladapis nagrii are sharper than that of Sinoadapis shihuibaensis. Adapid primates of Lufeng are more abundant than those of both India and Pa-kistan and the species from Lufeng seems to be more complex. It indicates that there is probably a major radiation of Miocene adapids in Lufeng. Sinoadapis of Lufeng clearly differs from both Indraloris and Siualapis from the Siwaliks of India and Pa-kistan. Judging from the Lufeng mammalian fauna, Lufeng hominoid site is younger in age than Nagri beds near Haritalyangar of India. The Lufeng species provides im-portant fossil evidence for the understanding of Miocene Adapids.