据11月14日的《科学》(Science)杂志报道说, 一个直立人的新化石发现提示,该种系的雌性具有宽大的骨盆,其功能是为了生产脑容量大的婴儿。Scott W. Simpson及其同事在埃塞俄比亚找到并近乎完全地复原了一个直立人成年雌性的骨盆。作为一种相对复杂工具的使用者,直立人被认为是第一个离开非洲及可能是第一个能够掌握火的人族动物。
基于对一具年轻男性“Turkana Boy”的骨骼的研究,研究人员先前得出结论:直立人身材高挑,形体消瘦,这可能是为了适应炎炎的热带环境或是为了适应耐久性跑动。一个狭窄的雌性骨盆还意味着直立人的婴儿在出生时脑容量相对较小,但在出生后会急剧地生长,这是一种与现代人婴儿相同的特征。但是,新发现的骨盆的形状提示,直立人的婴儿比先前认为的要大30%,而其产前脑的生长速度与人类的类似,但其在产后脑和身体的生长速度则处在黑猩猩与人类之间。研究人员得出结论,需要生产脑容量大的婴儿是导致直立人雌性骨盆形成这种形状的最初的驱动力量。他们对为了适应热带气候或耐久性跑动是决定该种系骨盆形状的想法提出了怀疑。(生物谷Bioon.com)
生物谷推荐原始出处:
Science,Vol. 322. no. 5904, pp. 1089 - 1092,Scott W. Simpson,Sileshi Semaw
A Female Homo erectus Pelvis from Gona, Ethiopia
Scott W. Simpson,1,2 Jay Quade,3 Naomi E. Levin,4,5 Robert Butler,6 Guillaume Dupont-Nivet,7 Melanie Everett,8,9,10 Sileshi Semaw9,10*
Analyses of the KNM-WT 15000 Homo erectus juvenile male partial skeleton from Kenya concluded that this species had a tall thin body shape due to specialized locomotor and climatic adaptations. Moreover, it was concluded that H. erectus pelves were obstetrically restricted to birthing a small-brained altricial neonate. Here we describe a nearly complete early Pleistocene adult female H. erectus pelvis from the Busidima Formation of Gona, Afar, Ethiopia. This obstetrically capacious pelvis demonstrates that pelvic shape in H. erectus was evolving in response to increasing fetal brain size. This pelvis indicates that neither adaptations to tropical environments nor endurance running were primary selective factors in determining pelvis morphology in H. erectus during the early Pleistocene.
1 Department of Anatomy, Case Western Reserve University School of Medicine, Cleveland, OH 44106–4930, USA.
2 Laboratory of Physical Anthropology, Cleveland Museum of Natural History, Cleveland, OH 44106, USA.
3 Department of Geosciences/Desert Laboratory, University of Arizona, Tucson, AZ 85721, USA.
4 Department of Geology and Geophysics, University of Utah, Salt Lake City, UT 84112, USA.
5 Division of Geological and Planetary Sciences, California Institute of Technology, MC 100-23, Pasadena, CA 91125, USA.
6 Department of Physics, University of Portland, Portland, OR 97203–5798, USA.
7 Faculty of Geosciences, Utrecht University, Budapestlaan 17, 3584 CD Utrecht, Netherlands.
8 Department of Geological Sciences, Indiana University, Bloomington, IN 47407, USA.
9 The Stone Age Institute, 1392 West Dittemore Road, Gosport, IN 47433, USA.
10 Center for Research into the Anthropological Foundations of Technology (CRAFT), Indiana University, Bloomington, IN 47405, USA.