European mustelids include the European polecat, Mustela putorius, and the steppe polecat, M. eversmanii. Both occur sympatrically in the Pannonian Basin, where M. eversmanii hungarica represents the westernmost part of the latter species and they allegedly hybridize. We investigated the morphological relationships in sympatric and allopatric populations of these mustelids with representative sampling, taxonomic and geographic coverage. We evaluated inter- and intraspecific patterns of morphological differentiation of 20 cranial measurements and four external traits by distance-based morphometric approaches and multivariate analyses. Our results revealed a considerable heterogeneity in cranial morphology. The two species appeared to be clearly differentiated although sympatric populations were closer to each other and had a slight overlap in the morphometric space. Within M. eversmanii, the subspecies and the nominal taxon only partially overlapped, and M. eversmanii eversmanii was more distant from M. putorius than subspecies hungarica. Although morphometric analyses revealed several intermediate individuals in size in sympatric M. eversmanii and M. putorius populations, only a small fraction of such specimens showed conflict in discrete morphological characters with the diagnostic discriminant function. We interpret these results as an indication of ongoing hybridisation between sympatric populations, but the low number of hybrids identified suggests limited genetic exchange between the species.

欧洲的鼬类动物包括欧洲臭鼬猫，鼬鼬（Mustela putorius）和草原臭鼬猫（M. eversmanii）。两者都同伴发生在Pannonian盆地，那里的M. eversmanii hungarica代表后者物种的最西端，据称它们杂交。我们用代表性的采样，分类学和地理覆盖范围调查了这些胡须类动物的同伴和同种异体种群中的形态学关系。我们通过基于距离的形态计量学方法和多元分析，评估了20种颅骨测量和4种外部特征的种间和种内形态分化模式。我们的研究结果表明颅骨形态上存在相当大的异质性。尽管同胞种群彼此更接近，并且形态空间略有重叠，但这两个物种似乎已明显区分。在eversmanii内，亚种和名义分类仅部分重叠，eversmanii eversmanii与腐霉菌比匈牙利亚种更远离。尽管形态计量学分析揭示了同胞华氏疟原虫和恶性疟原虫种群中几个中间个体的大小，但此类样本中只有一小部分显示出离散的形态特征与诊断判别功能发生冲突。我们将这些结果解释为同胞种群之间正在进行杂交的迹象，但鉴定出的杂种数量较少表明物种之间的遗传交换有限。