First Fossil Chimpanzee

遗传证据表明，黑猩猩(潘)是现存的与人类最接近的亲戚。在过去的30年里，数十名研究人员的勤奋探索创造了人类血统的化石记录，目前已有数千个标本。但在麦克布雷蒂2005年在肯尼亚的Kapthurin地层中发现黑猩猩化石之前，还没有已知的黑猩猩化石。缺乏我们近亲的化石记录一直是许多猜测的对象。由于活着的黑猩猩种群生活在树木繁茂的西非和中部非洲，而大多数原始人化石遗址位于半干旱的东非裂谷，可能是由于气候变化的驱动，从森林植被向草原植被的转变被认为是500万到800万年前人类和黑猩猩血统的差异造成的。裂谷本身被认为是黑猩猩占领的障碍。卡普图林组化石表明，大约50万年前，潘的代表曾出现在东非裂谷，在那里他们与已灭绝的人种同时代。这表明人类和黑猩猩的祖先可能占据了非常相似的栖息地，需要重新评估植被和气候变化在两条线最初分歧中的作用。拟议的项目将进一步探索和挖掘卡普图林组，以恢复更完整的黑猩猩化石标本。这项研究还将通过研究其他动物的相关化石遗骸，详细检查化石的地质背景，以及古土壤和化石牙釉质中碳酸盐的稳定同位素分析，来澄清古代黑猩猩生活的栖息地。更广泛的影响包括康涅狄格大学研究生、当地肯尼亚工作人员和肯尼亚国家博物馆古生物部人员的合作，他们都将参与这项研究。他们的角色将包括化石勘探、测绘和挖掘，以及化石识别、准备和管理。该项目是与NMK长期合作的一部分，化石最终将存放在NMK。

Genetic evidence shows that the chimpanzee (Pan) is the closest living relative to humans. Diligent prospecting by dozens of researchers over the last 30 years has resulted in a fossil record for the human lineage that now numbers in the thousands of specimens. But prior to McBrearty's discoveries in the Kapthurin Formation, Kenya, reported in the Journal Nature in 2005, there were no known fossils of the chimpanzee. The lack of a fossil record for our closest relative had been the object of much speculation. Because living chimpanzee populations inhabit wooded West and Central Africa, while most hominin fossil sites occur in the semiarid East African Rift Valley, a shift from forest to grassland vegetation, perhaps driven by climate change, was thought to have caused the divergence between the human and chimpanzee lineages 5 to 8 million years ago. The Rift Valley itself was thought to present an obstacle to chimpanzee occupation. The Kapthurin Formation fossils show that representatives of Pan were present in the East African Rift Valley about 500,000 years ago, where they were contemporary with an extinct species of Homo. This suggests that the ancestors of humans and chimpanzees may have occupied quite similar habitats, and calls for a reevaluation of the role of vegetation and climate change in the initial divergence between the two lineages.The proposed project will further explore and excavate in the Kapthurin Formation to recover more complete chimpanzee fossil specimens. The research will also clarify the habitat in which the ancient chimpanzees lived, through study of associated fossil remains of other animals, detailed examination of the fossils' geologic context, and stable isotope analysis of carbonates in ancient soil and fossil tooth enamel. Broader impacts include collaboration of University of Connecticut graduate students, local Kenyan workers, and personnel from the Palaeontology Division of the National Museums of Kenya (NMK), all of whom will take part in the research. Their roles will include prospecting for fossils, mapping, and excavation, as well as fossil identification, preparation, and curation. The project is part of a long-term collaboration with the NMK, where the fossils will ultimately be housed.