On the morphological distinctness of the hybrid between the sable and pine marten

Abstract

52 The pine marten (Martes martes L., 1758) and, especially, the sable (Martes zibellina L., 1758) are valuable furbearing species. The marten mainly inhabits northwestern Eurasia, whereas the sable range is in the northeast of the continent. However, the ranges of these species overlap in the Ural and Trans� Ural regions. The pine marten, either due to its higher ecological flexibility or as a result of hybridization, can replace the sable and occupy the former sable stations (1, 2). Here, in the zone of transgression, crossing (so� called kidussization) occurs between species; their hybrid is called kidus. The phenomenon of interspe� cific hybridization of these two valuable furbearing species has not only biological, but also economic importance, because there is a risk of local decrease in the resources of the sable, a more valuable furbearing species. The identification of hybrids between morphologi� cally similar species is inevitably connected with methodical difficulties. Not only morphological, but also genetic similarity between the sable and pine mar� ten has been retained. However, neither crossing between kiduses accumulation crossing of male sables with female kiduses has yielded offspring thus far (3-5). Male kiduses are considered reproductively sterile (2), because offspring was obtained only from the female kiduses and male martens; this fact leaves the possibil� ity of introgressive hybridization. In the present study, we attempted to reveal cranio� logical characteristics of the sable and pine marten hybrids with the help of comparative formalization by the method of geometric morphometry (6-8). Com� parisons have been done on the basis of one cranial construction, namely the bulla ossea region. It is used by a number of authors (9-11) as a diagnostic charac� ter of