关键词: 粗壮池猿;头骨;上猿;晚中新世;禄丰;系统关系

Abstract: The paper deals with the Laccopithecus robustus eranium (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 trigonum 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 ete.
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 H. leuciscus from Java. All facts as well as the presence of Kansupithecus and Amphipithecus give a clue to the Asian origin of the extant hylobatids.

Key words: Laccopithecus robustus; Cranium; Pliopithecus; Lufeng; Phylogenetic relationship