Abstract

In this study, we analyse a species complex in Epidendrum, a mega-diverse Neotropical orchid genus, that is formed by the 11 Brazilian species of the E. difforme group. Although this group (c. 100 taxa) exhibits relatively high levels of floral variation, the Brazilian species are similar, making delimitation problematic. Here we combine molecular (phylogenetics), morphological (geometric morphometrics), genome size and cytogenetic (chromosome counts and CMA/DAPI staining) data to investigate circumscription of these species. Our results were interpreted by looking for congruence of the results as a means to delimit species. The studied taxa appear to be monophyletic, and karyotypically all analysed accessions were 2n = 40. Their 1C values vary from 1.99 ± 07 pg to 2.84 ± 0.12 pg. We did not find evidence for recent polyploidy or dysploidy and, apparently, these phenomena have not been important in the evolution of this species complex. On the other hand, we found high levels of polymorphism for CMA/DAPI banding, and variation in genome size appears to be positively correlated with latitude. Geometric morphometrics indicate that E. sanchezii and E. anatipedium/E. amarajiense are distinct from the remaining species, and three groups of other species can be separated using canonical variables analysis (CVA). Variation in lip shape, genome size and heterochromatin patterns of the taxa are not fully congruent with the phylogenetic analysis, but our results allowed us to delimit with full confidence four species: E. amapense, E. anatipedium (including E. amarajiense), E. pseudodifforme (including E. campaccii and E. thiagoi) and E. sanchezii. Four others will be tentatively maintained but need further study. Our results indicate that it will be necessary to reassess many of the species complexes in the genus using a similar multidisciplinary perspective to evaluate the number of taxa that should be recognized.

中文翻译：

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物种过多：表皮（Laeliinae；兰科）中巴西物种复合体的形态计量学，分子系统发育和基因组结构比以前认为的要少

摘要

在这项研究中，我们分析了表皮（Epidendrum）中的一种物种复合体，它是一种由新的E. difforme组的巴西物种组成的巨型新热带兰花属。虽然这种基团（Ç。100类群）呈现相对高含量的花香变化，巴西物种是相似的，使得划界问题。在这里，我们结合分子（系统发育），形态（几何形态），基因组大小和细胞遗传学（染色体计数和CMA / DAPI染色）数据来研究这些物种的限制。我们通过寻找结果的一致性来解释物种，以此来解释我们的结果。所研究的分类单元似乎是单系的，并且核型分析中所有被分析的种质均为2 n=40。它们的1C值从1.99±07 pg到2.84±0.12 pg。我们没有发现最近的多倍体或二倍体的证据，显然，这些现象在该物种复合体的进化中并不重要。另一方面，我们发现CMA / DAPI带具有较高的多态性，并且基因组大小的变化似乎与纬度呈正相关。几何形态计量学表明E. sanchezii和E. anatipedium / E. amarajiense与其余物种截然不同，可以使用规范变量分析（CVA）将其他三个物种分开。分类学的唇形，基因组大小和异染色质模式的变化与系统发育分析并不完全一致，但我们的结果使我们能够完全确定地划定四种物种：E。amapense，E。anatipedium（包括E. amarajiense），E假单歧杆菌（包括E. campaccii和E. thiagoi）和E. sanchezii。暂时将维护其他四个，但需要进一步研究。我们的结果表明，有必要使用类似的多学科视角来重新评估该属中的许多物种复合体，以评估应被识别的分类单元的数量。