Pierre Lemelin, an assistant professor of anatomy at the University of Alberta in Edmonton, Canada, and a team of fellow American researchers have analyzed the first hand bones ever found of Hadropithecus stenognathus, a lemur that lived 2,000 years ago.

The bones were discovered in 2003 in a cave in southeastern Madagascar, an island nation off the coast of Africa in the Indian Ocean. Hadropithecus is related to the modern-day sifaka, a type of lemur with acrobatic leaping skills. A lemur is a monkey-like animal with a long tail and large eyes.

An examination of the five tiny hand bones by Lemelin and the rest of the research team revealed a never-before-seen hand joint configuration on the side of the little finger. The same joint configuration is straight in all other primates, including Archaeolemur, a close extinct relative of Hadropithecus.

"Our analysis showed a mosaic of lemurid-like, monkey-like and very unique morphological traits," Lemelin said. "Because the joint was present on both hands, it's likely not an anomaly, but because there are no other Hadropithecus hand bones for comparison, we don't know for certain," Lemelin said. "It is a mystery, and further investigation is needed to explain the difference in this species."

Lemelin and his colleagues from George Washington University, the Medical College of Georgia, and the universities of Stony Brook and Massachusetts at Amherst, also discovered that, unlike its close living relatives, Hadropithecus lacked anatomical traits linked with wrist mobility and strong finger flexion that characterize primate species that climb or cling to trees.

The hand bones also showed that Hadropithecus had very short thumbs and was a quadrupedal species, walking on all fours, much like many primates, such as baboons, do today. The discovery underscores the amazing diversity of lemurs that existed more than 2,000 years ago, when lemurs of all types ranged from pocket-sized to the size of gorillas, Lemelin noted.

The findings were published this month in the Journal of Human Evolution.

The study was funded by the Natural Sciences and Engineering Research Council of Canada and The Leakey Foundation.

      手骨是在2003年发现于马达加斯加（位于非洲印度洋沿岸的岛国）东南部的一个山洞里。巨型狐猴与今天有着高超跳跃能力的维氏冕狐猴是近亲。狐猴是一种有着长尾巴和大眼睛的类猴动物。     

      莱蒙林和研究小组通过检测发现，巨型狐猴有着从未见过的小指关节构造。同样的关节在其他动物身上应该是笔直的，其中也包括巨型狐猴已灭绝的近亲，古狐猴。

      “我们的分析显示，巨型狐猴的小指呈现出了一种兼具狐猴、猴类和自身特色的形态特征。”莱蒙特说，“关节部位的异常同时出现在两只手上，说明了这不是普通的反常现象，但是又因为没有其他的巨型狐猴手骨进行更多的检测比较，所以我们也不能确定其小指关节就是呈拱形结构的。这非常奇怪，因此我们需要进一步的研究去解释巨型狐猴的这一奇特现象。”

      莱蒙林和他来自乔治华盛顿大学、乔治医学院、石溪大学和麻省大学艾姆赫斯特本部的同事们，还发现巨型狐猴不同于它在世的近亲们，它缺少手腕、手指灵活性的解剖学特征，这些特征用于攀爬和抓附树木，可以鉴别灵长类动物。

      手骨还显示了巨型狐猴有着非常短的拇指，是一类四足动物，即同时用四条腿走路，这点与今天狒狒等许多灵长类动物十分相似。这一发现突显了巨型狐猴与2000年前其他身型各异的同类们的差异性。

      这个发现刊登于本月的《人类进化周刊》。

      这项研究由加拿大自然科学和工程研究委员会以及李基基金提供赞助。