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

0089612伦德伯格费城自然科学院的约翰·伦德伯格博士与来自阿根廷、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科大约90种“虎纹”鲶鱼的系统学、进化和地理学。它们是形态和生态多样的高价值食用鱼，分布在南美洲东部的广阔河流流域，包括亚马逊河，奥里诺科河和巴拉那河流域，也有来自安第斯山脉河流的物种。在南美同事的帮助下，将对该科所有31个描述的属进行采样，并将对由此获得的预期70-80个物种进行线粒体和核基因的DNA序列分析，以通过比较物种间的突变差异构建系统发育树。对这些样本和博物馆藏品的形态学研究将补充分子系统发育分析，法国和南美的同事也将增加对这一组化石的研究，其中20个是目前已知的，来自始新世时期的沉积物，但怀疑可以追溯到白垩纪。 pimelodine鲶鱼的年代发育将与地理学数据和南美洲大型河流和盆地的历史重建相结合。这些鱼类的亚类内的时间模式和多样化率，以及它们与地球历史事件的时间序列关系，将提供南美生物进化的可疑因果因子的测试。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，其中许多人将前往费城参加重点工作会议，以整合分子，形态和古生物学信息。

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.