Ronikier Anna, Lado Carlos
Institute of Botany, Polish Academy of Sciences, Lubicz 46, 31-512 Kraków, Poland
Real Jardín Botánico, CSIC, Plaza de Murillo 2, 28014 Madrid, Spain.
Mycologia. 2015 Mar-Apr;107(2):258-83. doi: 10.3852/14-164. Epub 2014 Dec 30.
Nivicolous myxomycetes occur at the edge of spring-melting snow in mountainous areas. They are mostly considered cosmopolitan species morphologically and ecologically uniform across their entire distribution ranges. Thus, long-distance dispersal has been suggested to be the main mechanism shaping their ranges and geographical variability patterns. To test this hypothesis we conducted the first detailed analysis of morphological variability, occurrence frequency and phenology of nivicolous myxomycetes collected in the hitherto unexplored Austral Andes of South America (southern hemisphere = SH) in the comparative context of data from the northern hemisphere (NH). We used Stemonitales, the most representative and numerous taxonomic order in nivicolous myxomycetes, as a model. A total of 131 South American collections represented 13 species or morphotypes. One of them, Lamproderma andinum, is new to science and described here. Several others, L. aeneum, L. album, L. pulveratum, "Meriderma aff. aggregatum ad. int.", M. carestiae and "M. spinulosporum ad. int.", were previously unknown from the SH. Lamproderma ovoideum is reported for the first time from South America and Collaria nigricapillitia is new for Argentina. The fine-scale morphological analysis of all species from the study area and reference NH material demonstrated a high intraspecific variability in most of them. This suggests isolation and independent evolutionary processes among remote populations. On the other hand, the uniform morphology of a few species indicates that long-distance dispersal is also an effective mechanism, although not as universal as usually assumed, in some nivicolous myxomycetes. Analysis of nivicolous species assemblages also showed significant differences among major geographic regions in that the Stemonitales were significantly less common in the SH than in the NH. Furthermore, the occurrence of nivicolous species in summer and autumn, out of the typical phenological season, is recognized as a possible distinctive phenomenon for the SH populations.
雪栖黏菌出现在山区春季融雪的边缘地带。它们在形态和生态上大多被认为是世界性物种，在其整个分布范围内具有一致性。因此，远距离传播被认为是塑造其分布范围和地理变异模式的主要机制。为了验证这一假设，我们首次对在南美洲此前未被探索的安第斯山脉南部（南半球=SH）收集的雪栖黏菌的形态变异、出现频率和物候进行了详细分析，并与北半球（NH）的数据进行了比较。我们以黏菌纲中最具代表性且数量最多的分类目——发网菌目作为模型。总共131份来自南美洲的样本代表了13个物种或形态型。其中之一，安第斯亮皮菌，是科学上新发现的物种，并在此处进行描述。其他几个物种，铜色亮皮菌、白色亮皮菌、粉状亮皮菌、“聚合近缘团皮菌”、卡雷斯蒂团皮菌和“小刺孢团皮菌”，此前在南半球尚不为人知。卵形亮皮菌首次在南美洲被报道，而黑鬃团网菌对阿根廷来说是新物种。对研究区域内所有物种以及来自北半球的参考样本进行的精细尺度形态分析表明，它们中的大多数都具有较高的种内变异性。这表明偏远种群之间存在隔离和独立的进化过程。另一方面，少数物种形态的一致性表明，尽管不像通常所认为的那样普遍，但远距离传播在一些雪栖黏菌中也是一种有效的机制。对雪栖物种组合的分析还表明，主要地理区域之间存在显著差异，即发网菌目在南半球比在北半球明显少见。此外，雪栖物种在典型物候季节之外的夏季和秋季出现，被认为是南半球种群可能具有的独特现象。
