Department of Environmental and Plant Biology, Ohio University, Athens, OH, USA.
Mycologia. 2013 May-Jun;105(3):610-35. doi: 10.3852/11-332. Epub 2013 Feb 8.
Ten small dictyostelids isolated from samples collected from the surface humus layer of seasonal rainforests of Belize and Guatemala were studied morphologically, and nine were found to represent distinct species, all with an average height of < 2 mm (0.5-3.5 mm). Although their fruiting bodies (sorocarps) closely resemble one another, the nine species differ in their patterns of aggregation, stream pattern, branching development, formation of microcysts, spore shape, presence or absence of spore granules and their distribution, as well as in the shapes and behavior of their sorogens and myxamoebae. These stable morphological features were sufficient to recognize nine new species of small dictyostelids, one with two varieties. SSU rDNA sequences were generated for all these new isolates, and phylogenetic analyses of these sequences show these new isolates belong to Dictyostelid group 3. As a result of this and other recent studies, the concept of what constitutes a species in the dictyostelids has become much more restricted and well defined, in as much as some of the morphological and behavioral patterns now being observed were overlooked in the past. The extent, flow direction and conformation of streaming within the group varies from simple aggregation mounds with no streams to short streams, to somewhat longer streams and finally to well developed streams. Each of these is characterized by a particular set of distinguishing features.
从伯利兹和危地马拉季节性雨林表土腐殖质层采集的 10 株小型粘菌被分离出来进行形态学研究，其中 9 株被鉴定为不同的种，平均高度均<2mm（0.5-3.5mm）。尽管它们的子实体（包果体）非常相似，但这 9 个种在聚集方式、流纹模式、分支发育、微囊形成、孢子形状、是否有孢子粒及其分布以及包囊体和变形体的形状和行为上存在差异。这些稳定的形态特征足以识别出 9 种新的小型粘菌，其中 1 种有两个变种。对所有这些新分离物都生成了 SSU rDNA 序列，这些序列的系统发育分析表明这些新分离物属于粘菌组 3。由于这一研究以及其他近期的研究，粘菌中种的概念变得更加严格和明确，因为过去一些形态和行为模式被忽视了。组内流的范围、流向和形态各不相同，从没有流的简单聚集丘到短流，到稍长的流，最后到发育良好的流。每种流都有其独特的特征。
