The Origin of Geographic Diversity in the Bahamian Land Snail Cerion: The Fossil History of Modern Patterns

巴哈马陆地蜗牛 Cerion 地理多样性的起源：现代模式的化石历史

• 批准号: 0106936
• 负责人: Myroslaw Harasewych
• 金额: --
• 依托单位: George Washington University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-07-01 至 2007-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0106936&HistoricalAwards=false
• 关键词: Origin; Geographic; Diversity; Bahamian; Land

ABSTRACTThe origin of geographic diversity in the Bahamian land snail Cerion: the fossil history of modern patternsGlenn A.Goodfriend, Stephen J. Gould, and M. G. HarasewychEAR-0106936 The land snail Cerion is noteable for its extreme geographic diversity in shell morphology: very different forms occur adjacent to each other, with steep character gradients between them. This study is aimed at revealing the history and possible causes of the geographic diversity along a stretch of ca. 12 km of the east coast of Long Island, Bahamas, where 5 distinctive forms occur. Starting with the geographic patterns of the modern (living) forms, we will follow these patterns back in time through excavation and analysis of the Holocene fossil record of the snails present in the eolian sand deposits along the coast. Ca. 20-35 shells from each of ca. 25-30 sites will be dated by amino acid racemization (calibrated against a series of radiocarbon ages) and analyzed morphmetrically to obtain temporal and geographic series. PIs will evaluate several alternative scenarios concerning the origin of geographic diversity in these snails:1. The patterns are relatively stable and old, resulting from in situ differentiation of geographically continuous populations of snails. Selection would be the primary cause of geographic diversity.2. Geographic patterns are relatively dynamic and result from population dynamic processes such as dispersal and extirpation. These patterns could have various origins:a. Destriuction of Cerion populations across a broad region by, e.g., a hurricane, opens up a broad region for recolonization by snails originating from nearly sources or long-distance dispersal; the populations expand and meet. Broad scale environmental events would be the primary control of geographic diversity.b. Cerion populations are typically in a state of flux, with local extirpations and re-establishment of populations, sometimes from long-distance dispersal. Stochastic population processes and smaller scale environmental events (e.g., washover fans from storms) would be the primary control.Based on preliminary results, we can expect to have a detailed record of Cerion back to ca. 5000-6000 yr BP. A parallel study will look at the relationships of living forms using mDNA sequences. These studies will contribute to understanding the origin and maintenance of geographic diversity of organisms.

摘要巴哈马陆地蜗牛 Cerion 地理多样性的起源：现代图案的化石历史Glenn A.Goodfriend、Stephen J. Gould 和 M. G. HarasewychEAR-0106936 陆地蜗牛 Cerion 以其贝壳形态的极端地理多样性而闻名：彼此相邻的形态非常不同，它们之间具有陡峭的特征梯度。 这项研究旨在揭示大约一段地区地理多样性的历史和可能的原因。巴哈马长岛东海岸 12 公里处，出现了 5 种独特的形态。 从现代（生命）形式的地理模式开始，我们将通过挖掘和分析沿海风成沙沉积物中存在的蜗牛的全新世化石记录，追溯这些模式。 约。每个约 20-35 个炮弹。 25-30个地点将通过氨基酸外消旋作用（根据一系列放射性碳年龄校准）来确定年代，并进行形态测量分析以获得时间和地理序列。 PI 将评估有关这些蜗牛地理多样性起源的几种替代方案：1。这些模式相对稳定且古老，是地理上连续的蜗牛种群就地分化造成的。 选择是地理多样性的主要原因。2．地理格局是相对动态的，是由人口动态过程（例如分散和灭绝）造成的。 这些模式可能有不同的起源：飓风等对大片地区的塞里翁种群造成的破坏，为源自近源或远距离扩散的蜗牛重新定居开辟了广阔的区域；人口扩大并相遇。 大规模的环境事件将是地理多样性的主要控制因素。 Cerion种群通常处于流动状态，局部灭绝和种群重建，有时是长距离分散。 随机人口过程和较小规模的环境事件（例如，风暴带来的冲刷扇）将是主要控制因素。根据初步结果，我们预计将获得大约 10 世纪 Cerion 的详细记录。距今 5000-6000 年。 另一项平行研究将利用 mDNA 序列来研究生命形式的关系。 这些研究将有助于了解生物地理多样性的起源和维持。