Collaborative Research: Cetacean Phylogeny: A Reconciliation of Fossil and Neontological Data and the Importance of Taxonomic Sampling

合作研究：鲸类系统发育：化石和新生儿数据的协调以及分类采样的重要性

• 批准号: 9985847
• 负责人: John Gatesy
• 金额: $ 5.2万
• 依托单位: University of Wyoming
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-11-15 至 2001-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9985847&HistoricalAwards=false
• 关键词: Collaborative; Research; Cetacean; Phylogeny; Reconciliation

9985847Gatesy Biologists hypothesize that cetaceans (whales) evolved from terrestrial land mammals as many as 60 million years ago or more. This evolutionary transformation is one of the most remarkable known because it involved dramatic changes in size and shape. If we can understand this evolutionary transition it may serve as a model problem describing how evolutionary novelties appear. Fossils, like Ambulocetus, are excellent evidence that whales once had legs and walked on land. During their long evolutionary history whales have, however, lost their hind limbs and hair, developed specialized skulls to feed and hear underwater, and in some cases exceeded the largest dinosaur in body size relative to their ancestors of over 50 million years ago. In order to understand the details of how, why and when this evolutionary transformation occurred, it is important to develop a well-corroborated phylogenetic tree (family history) for whales and their close relatives. Ideally it would be of interest to study the anatomy and molecular biology of all species that are closely related to whales. These include living and extinct groups: Artiodactyla, or even-toed hoofed mammals (camels, pigs, ruminants, hippopotamids and relatives), Perissodactyla, or odd-toed hoofed mammals (horses, rhinos, tapirs and relatives), as well as Procreodi, Condylarthra and Mesonychia, completely extinct groups of hoofed mammals. In particular among the extinct groups, Mesonychia may be very closely related to cetaceans. Most of the taxa ( 90%) that make up the group of interest outlined above are extinct. As a result, scientists trying to generate a phylogenetic tree for whales are forced to work with only part of the data whether they study living animals or extinct animals. Those working on living animals (neontologists) draw on very detailed biological characters (e.g., all of the organisms' anatomy, molecular biology, histology, etc) but only in one instant of time: the present. Those working on extinct species (paleontologists) draw on fossil evidence which almost exclusively comprises skeletal data. However, these data can be scored for many more species, some of which may more closely approximate the ancestral condition of the earliest whales. Here we propose to integrate neontological and paleontological data, to better examine the phylogenetic tree of cetaceans. This is critical to do at this time because scientists working on different data types continue to find different answers as to who is the closest relative of whales: living taxa indicate that it is the hippopotamus and extinct taxa indicate that it is mesonychians. We aim 1) to increase the taxon and character sampling for both extinct and living whales and relatives, and 2) to examine how and why certain biological attributes (e.g., molecules, morphology) have evolutionary histories that do not appear to match the overall family tree. We aim to make the results of our morphological work as standardized as possible with published illustrations. The data collection aspect of this project is large and we will use this as an opportunity to mentor high school and undergraduate students who may be interested in research in evolution and systematics and who can be taught laboratory, computer, and data analysis skills as well as evolutionary theory.

盖特西生物学家假设，鲸目动物(鲸鱼)是在6000万年前或更久以前从陆地哺乳动物进化而来的。这种进化转变是已知的最引人注目的转变之一，因为它涉及到大小和形状的戏剧性变化。如果我们能够理解这种进化转变，它可能会成为描述进化新颖性如何出现的一个模型问题。像文昌鱼这样的化石是鲸鱼曾经有腿和在陆地上行走的极好证据。然而，在漫长的进化历史中，鲸鱼失去了后肢和毛发，形成了专门的头骨来在水下觅食和听力，在某些情况下，相对于5000多万年前的祖先，鲸鱼的身体尺寸超过了最大的恐龙。为了了解这种进化转变如何、为什么以及何时发生的细节，重要的是为鲸鱼及其近亲建立一个得到充分证实的系统发育树(家族史)。理想情况下，研究与鲸鱼密切相关的所有物种的解剖学和分子生物学将是有兴趣的。这些物种包括现存的和已灭绝的群体：偶趾目或偶趾有蹄哺乳动物(骆驼、猪、反刍动物、河马及近亲)、腹足亚目或奇趾有蹄哺乳动物(马、犀牛、绒猴及近亲)，以及Procreodi、Condylarthra和Mesonchia，这些都是完全灭绝的有蹄哺乳动物群体。特别是在已灭绝的种群中，中甲藻可能与鲸目动物有非常密切的关系。组成上述利益集团的大多数分类群(90%)已经灭绝。因此，试图为鲸鱼建立系统发育树的科学家被迫只使用部分数据，无论他们是研究活的动物还是灭绝的动物。那些研究活动物的人(新本体学家)利用非常详细的生物学特征(例如，所有有机体的解剖学、分子生物学、组织学等)，但只在一个瞬间：现在。那些研究灭绝物种的人(古生物学家)利用几乎完全由骨骼数据组成的化石证据。然而，这些数据可以用于更多的物种，其中一些可能更接近于最早的鲸鱼的祖先条件。在这里，我们建议整合新的和古生物学的数据，以更好地研究鲸目动物的系统发育树。这一点在此时至关重要，因为研究不同数据类型的科学家仍在寻找关于谁是鲸鱼最近亲属的不同答案：活着的分类群表明这是河马，灭绝的分类群表明它是中趾目动物。我们的目标是1)增加灭绝和存活的鲸鱼及其近亲的分类和特征样本，2)研究某些生物属性(例如，分子、形态)如何以及为什么具有似乎与整个家谱不匹配的进化史。我们的目标是使我们的形态工作的结果尽可能标准化与出版的插图。这个项目的数据收集方面很大，我们将利用这个机会指导高中和本科生，他们可能对进化论和系统学的研究感兴趣，可以学习实验室、计算机、数据分析技能和进化论。