Department of Integrative Biology and University Herbarium, and Jepson Herbarium, University of California, Berkeley, California 94720 USA.
Am J Bot. 2004 Feb;91(2):274-84. doi: 10.3732/ajb.91.2.274.
Jamesonia and Eriosorus are two traditionally recognized fern genera in the Neotropics that together form a monophyletic group. Molecular phylogenetic analyses for this study suggest, however, that neither genus is itself monophyletic and that several independent lineages with the jamesonia morphotype have each undergone a fairly recent radiation in páramo ecosystems. A robust phylogeny was generated based on sequence data of the nuclear external transcribed spacer (ETS) of 18S-26S rDNA, the plastid gene rps4 and the intergenic spacer rps4-trnS. Several conclusions can be made concerning the evolutionary history and biogeographic patterns of the Jamesonia-Eriosorus complex: (1) "jamesonia" is polyphyletic, making "eriosorus" paraphyletic; (2) all analyses recover three major clades in the Andes; (3) two well-supported clades can be recognized, corresponding to the northern vs. central Andes; and (4) the sister taxon of the Andean radiation is the Brazilian taxon Eriosorus myriophyllus. Jamesonia is a potential example of a recent adaptive radiation because the group is characterized as being morphologically and ecologically diverse and its habitat is of recent origin.
詹姆斯onia 和 Eriosorus 是两个传统上在 Neotropics 被认可的蕨类植物属，它们共同形成一个单系群。然而，这项研究的分子系统发育分析表明，这两个属本身都不是单系的，并且具有 jamesonia 形态的几个独立谱系在 páramo 生态系统中都经历了相当近期的辐射。基于核外部转录间隔区（ETS）的序列数据、质体基因 rps4 和基因间隔 rps4-trnS，生成了一个稳健的系统发育树。关于 Jamesonia-Eriosorus 复合体的进化历史和生物地理模式，可以得出以下几个结论：（1）“jamesonia”是多系的，使得“eriosorus”为并系的；（2）所有分析都在安第斯山脉中恢复了三个主要的分支；（3）可以识别出两个支持良好的分支，分别对应于安第斯山脉的北部和中部；（4）安第斯山脉辐射的姊妹分类群是巴西分类群 Eriosorus myriophyllus。Jamesonia 是一个潜在的最近适应性辐射的例子，因为该组在形态和生态上具有多样性，并且其栖息地是最近才出现的。
