生物谷報(bào)道：四年前在乍得發(fā)現(xiàn)了被稱為Toumai的頭骨，從此引發(fā)了一場爭論,。動物學(xué)研究表明,，該頭骨的年齡接近700萬年；而其較小的頭蓋則表明,，它的大腦跟黑猩惺的大腦差不多大,。發(fā)現(xiàn)Toumai的研究小組認(rèn)為它屬于一種原始人類，在黑猩猩與人類的分化中更靠近人類一邊,，但其他研究人員則認(rèn)為它更像猿?，F(xiàn)在，Toumai物種（Sahelanthrupus tchadensis）牙齒和頜骨碎片的發(fā)現(xiàn)表明,，該物種與猿相差較遠(yuǎn),，而與黑猩猩和人類最后的共同祖先關(guān)系很近。對Toumai頭蓋所做的虛擬重建為該物種與人類之間的密切關(guān)系提供了更多證據(jù),。本期Nature封面上所刊登的是已知最早原始人類的面部,。
該文發(fā)表在：Nature 434, 752 - 755 (07 April 2005); doi:10.1038/nature03392
New material of the earliest hominid from the Upper Miocene of Chad
MICHEL BRUNET1, FRANCK GUY1,2, DAVID PILBEAM2, DANIEL E. LIEBERMAN2, ANDOSSA LIKIUS3, HASSANE T. MACKAYE3, MARCIA S. PONCE DE LEÓN4, CHRISTOPH P. E. ZOLLIKOFER4 & PATRICK VIGNAUD1
1 Laboratoire de Géobiologie, Biochronologie et Paléontologie Humaine, CNRS UMR 6046, Faculté des Sciences, Université de Poitiers, 40 Avenue du Recteur Pineau, 86022 Poitiers Cedex, France
2 Peabody Museum, Harvard University, 11 Divinity Avenue, Cambridge, Massachusetts 02138, USA
3 Université de N'Djamena, BP 1117, N'Djamena, Tchad
4 Anthropologisches Institut/MultiMedia Laboratorium, Universität Zürich-Irchel, Winterthurerstrasse 190, 8057 Zürich, Switzerland
Correspondence and requests for materials should be addressed to M.B. ([email protected]).
Discoveries in Chad by the Mission Paléoanthropologique Franco-Tchadienne have substantially changed our understanding of early human evolution in Africa. In particular, the TM 266 locality in the Toros-Menalla fossiliferous area yielded a nearly complete cranium (TM 266-01-60-1), a mandible, and several isolated teeth assigned to Sahelanthropus tchadensis and biochronologically dated to the late Miocene epoch (about 7 million years ago). Despite the relative completeness of the TM 266 cranium, there has been some controversy about its morphology and its status in the hominid clade. Here we describe new dental and mandibular specimens from three Toros-Menalla (Chad) fossiliferous localities (TM 247, TM 266 and TM 292) of the same age. This new material, including a lower canine consistent with a non-honing C/P3 complex, post-canine teeth with primitive root morphology and intermediate radial enamel thickness, is attributed to S. tchadensis. It expands the hypodigm of the species and provides additional anatomical characters that confirm the morphological differences between S. tchadensis and African apes. S. tchadensis presents several key derived features consistent with its position in the hominid clade close to the last common ancestor of chimpanzees and humans.
