禄丰粗壮池猿头骨的初步观察——兼论池猿的系统关系

本文通过粗壮池猿头骨新材料的初步观察得出,它与欧洲上猿的头骨比较接近,而在某些特征上又与现生长臂猿相似。这与牙齿和颌骨研究的结果是一致的。本文还对亚洲第三纪长臂猿类与其他同时代长臂猿类的关系作了初步的探讨,并对池猿的系统关系作了论述。

PRELIMINARY OBSERVATION ON THE CRANIUM OF LACCOPITHECUS ROBUSTUS FROM LUFENG, YUNNAN WITH REFERENCE TO ITS PHYLOGENETIC RELATIONSHIP

The paper deals with the Laccopithecus robustus cranium (PA 860) which was collected from Lufeng, Yunnan in 1981.The cranium consists of most part of facial region, a part of the frontal and the maxilla with all teeth in situ except the right lateral incisor. The posterior part of the cranium is missing.The facial part of the left side is distorted due to compression in the process of fossilization while that of the right side is well-preserved.The upper face and nasals are short and broad. The interorbital pillar is broad and flat.The temporal ridges start from the middle part of the supra-orbital ridges on tri-gonum frontale, which are similar to that of Pliopithecus and Hylobates. Seven indices, the snout breadth index, snout length index, facial depth index, incisor breadth index, palatal breadth index, nasal breadth index, orbital breadth index, were calculated. The first four fall within the range of Pliopithecus and the rest three, of Hylobates etc.The P4 has developed lingual cingulum. Judging from the canines, PA 860 cranium is of a male individual.Its facial region resembles that of H. leuciscus in size. However, its dentition is larger than both H. leuciscus and other extant hylobatids in proportion of its face. Preliminary observation of PA 860 cranium indicates that it is similar to Pliopithecus on the one hand and to Hylobates on the other.As Laccopithecus was found in Yunnan and similar to H. concolor in some features, it is possible that Hylobates evolved from Laccopithecus robustus. In addition, the upper molars of Dionysopithecus shuangouensis are morphologically similar to those of E. leuciscus from Java. All facts as well as the presence of Kansupithecus and Amphi-pithecus give a clue to the Asian origin of the extant hylobatids.