日前,研究人员通过计算机虚拟拼凑最新发现的灭绝狐猴头骨碎片,现已成功地在计算机上呈现出这种巨型狐猴的完整头骨模型。据悉,巨型狐猴的学名叫做“Hadropithecus stenognathus”,其体型与现今的雌性狒狒大小相当。目前生活在马达加斯加岛的红领狐猴重9磅,而这种灭绝的巨型狐猴体重却达到65磅。
研究人员虚拟创建的完整巨型狐猴头骨的相关详细资料发表在本周出版的《美国国家科学院学报》上,据悉,迄今为止科学家只发现了巨型狐猴的两块头骨。纽约美国国家历史博物馆伊恩 塔特萨尔说,“这是一种非常罕见特殊的狐猴,之前我们对它的认识十分有限,仅掌握到成年体头骨的特征,与目前我们创建的头骨模型相差甚远。”据悉,他在《美国国家科学院学报》上同期研究报告中发表了评论注解。
这项最新研究是基于1899年对巨型狐猴的头骨发现,当时动物化石收集专家弗朗兹·西科拉教授在马达加斯加岛安德拉霍马那洞穴里发现这些头骨化石的;2003年,美国波兰特大学人类学家纳塔利·瓦塞利带领一支研究小组重返安德拉霍马那岛进行勘测,他们挖掘出某种神秘物种的头骨碎片和肢体骨骼。
他们将这些骨骼化石带回了波兰特大学进行分析,瓦塞利的同事蒂莫西·赖安和艾伦·沃尔克使用计算机X射线断层扫描技术(CT)对新骨骼化石进行了呈像,除了对这些化石样本进行CT扫描之外,研究小组还对巨型狐猴头骨进行了3D呈像。图像显示巨型狐猴是原猴亚目物种中大脑与身体比例最大的物种。
巨型狐猴长着巨大的骨冠状头骨,这非常类似于大猩猩,它具有强劲的口腔咀嚼肌肉。研究人员称,这暗示着这种灭绝狐猴经常食用坚硬的食物,比如:种子和坚果等。
这项研究不仅揭示了这种罕见狐猴的特征,同时也发现了一批马达加斯加岛狐猴物种。塔特萨尔告诉美国生活科学网站说,“这项研究非常重要,它对于理解研究狐猴物种的多样性具有很大帮助。现今当你来到马达加斯加岛,你所看到的狐猴物种仅是冰山一角,从某种程度上讲,该岛的完整动物种群与人类到达之后有很大的差异。”
1.6亿年前,马达加斯加岛开始从冈瓦纳超大陆分离,在1.24亿年前,该岛已形成一个独立成形的岛屿,从地理结构上与其他岛屿相分隔,马达加斯加岛具有其独特的植物群和动物群。狐猴的原始祖先出现于马达加斯加岛,最终变化形成8个物种,其中3个物种现已灭绝。当人类在2300年前出现在马达加斯加岛上时,几种狐猴也从此消失了。
塔特萨尔说,“狐猴物种在体型上有着较大的差异范围,像巨型狐猴这样最大的狐猴在人类抵达马达加斯加岛之后便灭绝了。我认为它们灭绝的原因是太容易被捕杀,它们的移动速度很缓慢,很容易被人类发现其踪迹。此外,由于它们具有较低的生殖率,更易于遭受攻击。”
据美国国家历史博物馆统计,目前,现存的几种狐猴物种仍处于濒危灭绝,其主要原因是森林过度采伐,但同时也由于人类打猎和诱捕。(生物谷Bioon.com)
生物谷推荐原始出处:
PNAS published ahead of print July 28, 2008, doi:10.1073/pnas.0805195105
A reconstruction of the Vienna skull of Hadropithecus stenognathus
T. M. Ryan*, D. A. Burney†, L. R. Godfrey‡, U. B. Göhlich§, W. L. Jungers¶, N. Vasey‖, Ramilisonina**, A. Walker*,††, and G. W. Weber‡‡
Abstract
Franz Sikora found the first specimen and type of the recently extinct Hadropithecus stenognathus in Madagascar in 1899 and sent it to Ludwig Lorenz von Liburnau of the Austrian Imperial Academy of Sciences. Later, he sent several more specimens including a subadult skull that was described by Lorenz von Liburnau in 1902. In 2003, some of us excavated at the locality and found more specimens belonging to this species, including much of a subadult skeleton. Two frontal fragments were found, and these, together with most of the postcranial bones, belong to the skull. CT scans of the skull and other jaw fragments were made in Vienna and those of the frontal fragments at Penn State University. The two fragments have been reunited with the skull in silico, and broken parts from one side of the skull have been replaced virtually by mirror-imaged complete parts from the other side. The parts of the jaw of another individual of a slightly younger dental age have also been reconstructed virtually from CT scans with mirror imaging and by using the maxillary teeth and temporomandibular joints as a guide to finish the reconstruction. Apart from forming a virtual skull for biomechanical and systematic analysis, we were also able to make a virtual endocast. Missing anterior pieces were reconstructed by using part of an endocast of the related Archaeolemur majori. The volume is 115 ml. Hadropithecus and Archaeolemur seem to have had relatively large brains compared with the other large-bodied subfossil lemurs.