Continued Paleoanthropological Research in the Laetoli area, Tanzania

过去50年的古生物学研究证明，东非遗址对于记录人类进化的最早阶段具有重要意义。坦桑尼亚的莱托利是其中最重要的遗址之一。Laetoli之前的研究导致了化石的发现，这些发现对改善对人类进化史的理解做出了重大贡献。该遗址非常重要，原因有几个：(1)它拥有最大的早期南方古猿收藏之一，对于了解其解剖学、古生物学和系统发育状况非常重要。(2)足迹化石的发现为研究两足动物的起源提供了重要证据。(3)含原始人类的上Laetolil层，年代为3.5-3.8 Ma(百万年前)，采样的时间在东非通常很少被代表，因此在早期原始人类谱系的变异、时间趋势和进化变化的讨论中至关重要。(4)下Laetolil层(3.8 Ma~4.3 Ma)和上Ndolanya层(2.6~2.7 Ma)中也发现了化石，这表明Laetoli在2.5~5.0 Ma之间可能有助于更广泛地了解古人类的演化。(5)Laetoli有多样的动物群，可以作为与非洲其他地点进行比较的可靠参考。(6)莱托利古猿的古生态背景提供了有关古人类栖息地偏好和更新世生态变化的重要信息。该项目的目的是继续在莱托利进行长期的地质和古生物学调查。主要目标是找回更多的古人类化石，并获得有关古生物学、地质学和古生态学的进一步信息。具体目标是：(1)进行系统的地表采集；(2)寻找新的富有成效的古生物产状；(3)进行进一步的地质调查，以更好地了解地层和地质史；(4)获得更多的放射性年代，以更狭隘地限制化石赋存层位的年龄；(5)更准确地重建古生态；(6)更好地记录动植物的分类、演化关系和古生物学；科学价值：这些调查的结果将被用来解决古人类学中的几个关键问题：(1)更好地理解南方古猿和类人猿的解剖学、古生物学和系统发育关系；(2)更详细和更关键的评估莱托利人的古生态关系；以及(3)更全面的地质学、年代学和古生物学知识。更广泛的影响：Laetoli的持续研究和探索提供了产生关键新数据的潜力，这些数据将大大有助于更好地理解人类进化的化石证据。此外，该项目还为研究生提供了野外方法、地质学和脊椎动物古生物学方面的培训机会。该计划的国际范围还提供与坦桑尼亚和其他外国科学家和机构的合作教育和研究联系。

Paleontological research over the past fifty years has demonstrated the significance of sites in East Africa for documenting the earliest stages of human evolution. Laetoli in Tanzania is renowned as one of the most important of these sites. Previous research at Laetoli has led to fossil finds that have contributed significantly to an improved understanding of the evolutionary history of humans. The site is critically important for several reasons: (1) it has yielded one of the largest collections of the early hominid Australopithecus afarensis, and is important for understanding its anatomy, paleobiology and phylogenetic status. (2) The remarkable discovery of fossilized footprints provides crucial evidence for documenting the origins of bipedalism. (3) The hominid-bearing Upper Laetolil Beds, dated at 3.5-3.8 Ma (million years ago), sample a time period that is generally poorly represented in East Africa, and are therefore critical in discussions of variation, temporal trends and evolutionary change in early hominid lineages. (4) Fossils have also been recovered from the Lower Laetolil Beds (3.8 Ma to older than 4.3 Ma) and the Upper Ndolanya Beds (2.6-2.7 Ma), which suggests that Laetoli has the potential to contribute to a broader understanding of hominid evolution between 2.5-5.0 Ma. (5) Laetoli has a diverse fauna that serves as a well-dated reference for comparisons with other sites in Africa. (6) The paleoecological context of the hominids at Laetoli provides important information on hominid habitat preferences and on ecological changes during the Plio-Pleistocene.The aim of the project is to continue with long-term geological and paleontological investigations at Laetoli. The main objectives are to recover additional fossil hominids and to obtain further information on the paleontology, geology, and paleoecology. The specific goals are: (1) to conduct systematic surface collections; (2) to prospect for productive new paleontological occurrences; (3) to conduct further geological investigations, in order to gain a better understanding of the stratigraphy and geological history; (4) to obtain further radiometric dates to more narrowly constrain the ages of the fossil-bearing horizons; (5) to more accurately reconstruct the paleoecology; (6) to better document the taxonomy, evolutionary relationships, and paleobiology of the fauna and flora; and (7) to recover additional fossil hominids to improve our understanding of their anatomy, paleobiology and phylogeny.Scientific merits: Results from these investigations will be used to address several key issues in paleoanthropology: (1) a better appreciation of the anatomy, paleobiology and phylogenetic relationships of Australopithecus afarensis and Paranthropus aethiopicus; (2) a more detailed and critical assessment of the paleoecological associations of the Laetoli hominids; and (3) a more comprehensive knowledge of the geology, geochronology, and paleontology. Broader impacts: Continued research and exploration at Laetoli offers the potential to yield critical new data that will contribute significantly to a better understanding of the fossil evidence for human evolution. In addition, the project provides an important opportunity for graduate student training in field methods, geology and vertebrate paleontology. The international scope of the program also provides collaborative educational and research links with Tanzanian and other foreign scientists and institutions.