Pozdniakov A A
Zh Obshch Biol. 2011 Mar-Apr;72(2):127-39.
An analysis of morphotypical variability of the lower first molar in twelve species of Microtus genus revealed similarity in patterns of variability, consisting in two-three homologous series of three morphotypes of one class of rugosity in each series. In the majority of species, morphotypes are located in a single plane. In some species, morphotypes of other class of rugosity form the homologous series of a second plane so that the structure of the variability takes on a three-dimensional form. The variability spectrum is limited by molars design; at the different trends in complication of a masticatory surface have taxonomic weight of subgenus or species rank. Thus, incompleteness of homologous series is caused by taxonomic specificity and is nonrandom in essence.
对田鼠属12个物种的下颌第一磨牙形态型变异性的分析表明，变异性模式具有相似性，包括每个系列中一类皱纹的三个形态型的两到三个同源系列。在大多数物种中，形态型位于一个平面内。在一些物种中，其他类皱纹的形态型形成第二个平面的同源系列，从而使变异性结构呈现三维形式。变异性谱受臼齿设计限制；咀嚼面复杂化的不同趋势具有亚属或物种等级的分类学权重。因此，同源系列的不完整性是由分类学特异性引起的，本质上是非随机的。
