Neogene Caribbean Biotic Turnover and Evolution of Geminate Mollusc Species Separated by the Isthmus of Panama

巴拿马地峡分隔的新近纪加勒比海生物周转和双生软体动物物种的进化

• 批准号: 0344419
• 负责人: Peter Marko
• 金额: $ 29.51万
• 依托单位: University of North Carolina at Chapel Hill
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-01-15 至 2006-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0344419&HistoricalAwards=false
• 关键词: Neogene; Caribbean; Biotic; Turnover; Evolution

The rise of the Central American Isthmus (CAI) and the gradual closure of the seaway connecting the tropical Eastern Pacific (EP) and Western Atlantic (WA) oceans has long served as a model for understanding the formation of new species in the sea. Given geological information that dates the final stage of seaway closure at 3.1-3.5 million years ago, researchers have hypothesized that hundreds of morphologically similar pairs of species found today on either side of the isthmus (called "geminate" or twin species) are believed to represent the descendants of single ancestral species broadly distributed throughout the tropical EP and WA oceans prior to the isthmus formation. Recent evidence, however, raises questions about how closure of the CAI actually affected patterns of species diversity in tropical America. Given that extinction rates may have been as high as 70% for some groups following isthmus formation, researchers think that sister-taxa that survived in both oceans should be rare. How can the apparent survival of so many living geminate species in both the EP and WA be reconciled with the developing paleontological picture of massive Caribbean biotic turnover? To answer this question, Dr. Peter Marko of the University of North Carolina will conduct a combined molecular and paleontological analysis of speciation and extinction among geminate species complexes in the bivalve mollusk family Arcidae. Living species will be discriminated with a combination of phylogeographic surveys of nuclear and mitochondrial gene variation along with discriminant analysis of morphological traits. Species discrimination in the fossil record will then be accomplished by extending statistical tests of morphological differences among genetically distinct species in the living fauna to specimens from the fossil record. The research will provide financial support and training in field collections, morphometrics, and molecular phylogenetics for two graduate students plus funds to send students to a national meeting to gain experience presenting research results. Funds will also offer opportunities for undergraduate education and training in molecular research and the PI will actively recruit individuals from traditionally underrepresented groups. Although not directly funded by this proposal, the molecular phylogenetic work will also be integrated with a phylogenetic effort conducted by a morphological systematist in the UK.

中美洲地峡（CAI）的崛起以及连接热带东部太平洋（EP）和西大西洋（WA）海洋的海道的逐渐封闭，长期以来一直是理解海洋中新物种形成的模型。鉴于地质信息的日期为3.1-350万年前的海道闭合阶段的最后阶段，研究人员假设，今天在地峡的任何一侧发现了数百个在形态学上相似的物种（称为“ geminate”或twin them thects of the ep ep ep ep and thttropical ep and wae epy ins the the the ep ep and wa epecent in the the the the the ephems sepripation the the the the sepluct of isthmus the the Poilt the Toem the Toight of the Poilt of。然而，最近的证据提出了有关CAI如何实际影响热带美国物种多样性模式的问题。鉴于在地峡形成之后的某些组中，某些组的灭绝率可能高达70％，研究人员认为，在这两个海洋中幸存的姊妹塔克萨斯都应该很少见。在EP和WA中，这么多活生物的物种的明显生存与大规模加勒比生物周转的古生物学形象相吻合？为了回答这个问题，北卡罗来纳大学大学的彼得·马科（Peter Marko）博士将对双壳软体动物中的geminate物种复合物之间进行分子和古生物学分析和灭绝。活物种将通过核和线粒体基因变异的植物地理学调查以及形态特征的判别分析来区分。然后，将通过扩展生物动物区系中遗传上不同物种之间的形态学差异的统计检验来实现化石记录中的物种歧视，从化石记录中的标本进行统计学测试。这项研究将为两名研究生以及资金派遣学生参加全国会议，以获取研究成果的经验，以提供现场收集，形态计算学和分子系统发育学的财务支持和培训。资金还将为本科教育和分子研究培训提供机会，PI将积极招募传统代表性不足的群体的个人。尽管不是由该提案直接资助的，但分子系统发育工作也将与英国形态学系统主义者进行的系统发育努力相结合。