Phylogenetics of Pimelodine Catfishes: Exploring the Temporal and Geographical Contexts of Neotropical Fish Diversification

费城自然科学院的John Lundberg博士与来自阿根廷、巴西、法国和委内瑞拉的鱼类学同事一起，正在研究南美洲Pimelodinae科约90种“虎纹”鲶鱼的系统学、进化和生物地理学。它们是一类形态和生态多样化的高价值食用鱼，分布在南美洲东部的广大河流流域，包括亚马逊、奥里诺科和巴拉那流域，也有跨安第斯河的物种。在南美同事的帮助下，将对该科所描述的所有31个属进行采样，并将分析由此获得的预期70-80个物种的线粒体和核基因的DNA序列，以通过比较物种之间的突变差异来构建系统发育树。对这些样本和博物馆藏品的形态研究将补充分子系统发育分析，法国和南美的同事还将为这个群体增加对化石的研究，其中20个是目前已知的，来自始新世的沉积物，但被怀疑可以追溯到白垩纪。将结合生物地理数据和重建南美洲大河和盆地的历史，整合已过时的比目鱼的系统发育。这些鱼类亚纲内的时间模式和多样化速率，以及它们与地球历史事件的时序关系，将为南美洲生物进化中的可疑原因提供测试。这项研究的重要组成部分涉及来自阿根廷、巴西、法国和委内瑞拉的同事，他们中的许多人将前往费城参加有重点的工作会议，以整合分子、形态和古生物信息。

0089612Lundberg With ichthyological colleagues from Argentina, Brazil, France, and Venezuela, Dr. John Lundberg of the Philadelphia Academy of Natural Sciences is studying the systematics, evolution, and biogeography of the 90 or so species of "tiger stripe" catfishes of the family Pimelodinae of South America. They are a morphologically and ecologically diverse group of highly valued food fishes that range throughout the vast river basins of eastern South America, including the Amazon, Orinoco, and Parana drainages, with species also known from trans-Andean rivers. All 31 described genera in the family will be sampled, with the help of South American colleagues, and the expected 70-80 species thus acquired will be analyzed for DNA sequences from mitochondrial and nuclear genes, for the construction of phylogenetic trees from comparisons of the mutational differences among species. Morphological studies of these samples and of museum collections will complement the molecular phylogenetic analyses, and French and South American colleagues will also add studies of the fossils for this group, of which 20 are currently known, from deposits dated back to Eocene times but suspected to extend back to the Cretaceous. The dated phylogeny of pimelodine catfishes will be integrated with biogeographic data and reconstructions of the history of South America's large rivers and basins. The temporal patterns and rates of diversification within subclades of these fishes, and their time sequence relationships with Earth history events, will provide tests of suspected causal agents in South American biotic evolution. Significant components of the research involve colleagues from Argentina, Brazil, France, and Venezuela, many of whom will travel to Philadelphia for focused work sessions to integrate the molecular, morphological, and paleontological information.