【摘要】 本文记述的在云南元谋小河地区古猿地点发现的一种小型猿类．它的牙齿形态比晚中新世的禄丰粗壮池猿（Ｌａｃｃｏｐｉｔｈｅｃｕｓｒｏｂｕｓｔｕｓ）进步。而牙齿的某些形态介于粗壮池狼和现生长臂猿之间。它的发现为探讨现生长臂猿的起源与进化提供了新的化石依据．依哺乳动物群的初步研究，其时代稍晚于禄丰古猿地点的时代。鉴于它的形态特征和地史分布，作者将它订为一新属新种：进步滇猿Ｄｉａｎｏｐｉｔｈｅｃｕｓｐｒｏｇｒｅｓｓｕｓｇｅｎ．ｅｔｓｐ．ｎｏｖ．更多还原

【Abstract】 Yuanmou County is located in northern Yunnan Province about 100 km south-east of Kunming, the capital of Yunnan Province. The Xiaohe area hominoid sites are situated in the northwestern Portion of the Yuanmou Basin.The small-sized ape desCribed in this peper is associated with a large hominoid, Which was excavated by the Pint team from the Yunnan Provincial Museum and the Yuanmou Man EXhibition Hall from 1986 to 1990. The small-sized ape remains were recovered from Loc. 8801,8803 and 8807. All localities in the Xinohe area are roughly contemporary in age and are younger than the Lufeng hominoid site (8 Ma) on the basis of their mammalian fauna.The material includes 36 isolated teeth except C, I2 and P3. The small ape is named Dianopthecus progressus gen. et sp. nov. and distinguished from Laccortthecus robustus from Lufeng in that the buccal and lingual cingula are lacked or much reduced in the cheek teeth. The flat upper incisors are short and broad and the upper Premolar is subtriangular in outline with a dosely buccal and lingual cusps. The upper molars exhibit curved mesial and distal edgeS. The large P4 is characterized by a relahvely shallow taloned basin, the fovea anterior is reduced and there is a ridge from the anterior part of the Protoconid extending to the base of the crown. The distance between the protoconid and hppconid is relatively short and the hyPOconulid is reduced in the lower molars especially in M,. The lower molar has a small trianghr fovea Which is situated in the POsterior part of anterior fovea, between the Pfotocoaid and metaconid. Thegroove syStem confonns to the basic Dryrpithecus y-pattern in the M,.Dianorithecus psogressus gen. et sp. nov. is scalar to L. robustus in the week cingula, largeMa, reduced hypoconulid and mesiodistally elongated lingUal cusps in the lower molars,dtherphic canines, elongated lower molars and molariform P4.Table I Comparison of Dianopithecus pogressus g.. et sp. nov. with Laccorithecus robustus fromLIifmR and ement hviobahds (Hy lobates concolor, H.sy ndactylus)As described above, the dental morphology of Dianopthecus psogressus gen. et sp. nov. issimilar to Laecrpithecus robustus fIDm Lufeng in she and some morphological featUres and toH. syndactylus and H. co "color in other aspectS. The delltal morphology of Dianorithecusprogressus gen. et sp. nov. dabals from L. robustus with the exception of its ddrirphic canines.The morphology of D. mpressus is doser to that of modern gibbons than it is to L. robuStus. Inthe mammalinn fauna. Dorcabune, Prrpotamochoerus, MetaCervuluS, Munttacos and Hippetonare common but Selenoportax, which is present at the Lufeng holninoid site, is absent.Ailurorctos yUanmouensis and a prbotive srnainsized suid are only found in the YUanmouhondnoid site. The faunal changes indicate not only a change in the geological age but also achange in the Paleoenvironment.The reduchon of cahine dimorphism is one of the most forPOrtant occurrences duringgibbon evolution. Dianopithecus priorests shll presents the dimorphic canine although in otherrespects it is sdritar to extant hylobatids. The heightS of the canines, in the male and female, are12.0 rnxn and 7.3 mm, respechvely. It is therefore suggested that the reduCtion in sexualdforrphism in the cabines perhaps evolved late in the evolution of smalFshed apeS. Somemorphological features of DianOPthecus prrpressus gen. et sp. nov. are lute￣diate betWeenInccrpithecus robustus from Lufeng and extant hylobatids. It is, thus, intriguing and adds important infonnation toward the search for gibbon origins and also indicateS that Yunnan Province is a key area for the study of gibbon evolution.更多还原