Popova Lilia
Institute of Geology, National Taras Shevchenko University of Kyiv, Vasilkivska str. 90, Kyiv, 03022, Ukraine.
J Morphol. 2016 Jun;277(6):814-25. doi: 10.1002/jmor.20537. Epub 2016 Mar 28.
Discrete characters of the occlusal surface (additional cusps) have been studied to elaborate a new approach to the identification of the Ground Squirrel species Spermophilus odessanus, S. suslicus, S. pygmaeus, S. citellus, and S. xanthoprymnus. Data on the presence/absence of the additional cusps have been represented as star plots and, in addition, have been studied using discriminant function analysis. The species-specific sets of the characters (patterns of bunodonty) have been revealed and are of high diagnostic value. The Citellus-set is defined by the presence of mesostyles and the rareness of the metastylids, paraconules and metaconules, hypostyles and protostyles. The Pygmaeus-set is characterized by the presence of additional cusps in the lower cheek teeth. The Odessanus-oriented set is found in the Spermophilus pygmaeus, S. odessanus, and S. suslicus. The relatively high frequency of additional cusps of the metaloph and the paraloph is characteristic for this set. The Plesiomorphic-set (characters shared by all the studied species and for this reason regarded herein as ancestral) is found in S. xanthoprymnus. The patterns of bunodonty serve as diagnostic criteria only as a whole: the shape of a star plot (relations among the character frequencies), rather than certain character values, is indicative. An optimal level of identification of species is possible based on the combination of the discrete characters mentioned and on the size parameters of the third upper molar. The occlusal sets are intended to remain stable during the time of species existence and seem to correspond to trends in specialization. The functional meaning of the sets can be explained by the dependence between the presence/absence of the discrete characters and the shape of the crown and its main lophs. Each pattern is likely to correspond to a trophic niche, and this niche corresponds to the species. J. Morphol. 277:814-825, 2016. © 2016 Wiley Periodicals, Inc.
对咬合面的离散特征（额外的牙尖）进行了研究，以阐明一种鉴定黄鼠属物种奥氏黄鼠、苏氏黄鼠、侏儒黄鼠、灰黄鼠和黄纹黄鼠的新方法。关于额外牙尖存在与否的数据已表示为星形图，此外，还使用判别函数分析进行了研究。已揭示出特定物种的特征集（丘型齿模式），具有很高的诊断价值。灰黄鼠组的定义是存在中尖，且后尖、副小尖、原小尖、下尖和原尖较少见。侏儒黄鼠组的特征是下颊齿存在额外牙尖。奥氏黄鼠相关组见于侏儒黄鼠、奥氏黄鼠和苏氏黄鼠。该组的特征是金属嵴和副嵴的额外牙尖出现频率相对较高。原始组（所有研究物种共有的特征，因此在此被视为祖先特征）见于黄纹黄鼠。丘型齿模式仅作为一个整体用作诊断标准：星形图的形状（特征频率之间的关系）而非特定的特征值具有指示性。基于上述离散特征与第三上臼齿大小参数的组合，有可能实现物种鉴定的最佳水平。咬合组在物种存在期间应保持稳定，似乎与特化趋势相对应。这些组的功能意义可以通过离散特征的存在与否与牙冠形状及其主要嵴之间的依赖关系来解释。每种模式可能对应一个营养生态位，而这个生态位与物种相对应。《形态学杂志》277:814 - 825，2016年。© 2016威利期刊公司。
