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First record of lemmings (genus Dicrostonyx GLOGER, 1841) in Croatia

Among small mammal selected skeletal remains from the Romualdo's Cave in western Istria the teeth of lemmings (genus Dicrostonyx GLOGER, 1841) have been determined for the first time from the Late Pleistocene/Holocene? sediments in Croatia. The modern areal of this genus is Russia and Canada, and it has circumpolar distribution. During the Late Pleistocene, geographical distribution of this animals, which some authors call „a key species of the arctic community“, was more southern, what is documented by the findings from some European countries such as: England, France, Czech Republik, Hungary, Ukraine etc. These new specimens from Croatia push this border even more to the south. As the typical „ice-age element“ in the fauna of middle and southern European localities, Dicrostonyx is good indicator of cold and dry climate. Today these animals live in tundra and northern parts of forest-tundra areas, thus it can be concluded that similar habitats they inhabitat also in the past. The small sample of 11 teeth (first, second and third lower /M1-3/ and first upper /M1/ molars) originate from the sediments of the Romualdo's Cave in western Istria. The findings were found in the selected small mammal collection of the Institute for Quaternary paleontology and geology of Croatian Academy of Sciences and Arts, which is part of the faunal remains discovered by M. MALEZ and his team during the excavation seasons in 1960, 1962, and 1973. The stratigraphic proveniance of the sample is not clear, because it was mixed with other findings from the same site. The Dicrostonyx molars have been morphometrically analysed, and the resemblance has been observed in morphology, while some metrical parameters differ slightly in comparison to the findings from some other European localities, for example from Poland and Austria. The lenght of M1s for Croatian sample is bigger than for Austrian ones (e.g. Nixloch and Merkenstein Caves), while is smaller than for the Polish findings. The differences in A/L and C/W1 indices have also been observed between samples from the Romualdo's Cave and Polish sample of the Holocene age, in the way that Croatian teeth show higher values of A/L index, while C/W1 index is lower, respectively. Such small sample could not provide enough informations for more precise specific determinations. As good indicator of cold and dry climate, the lemmings from the Romualdo's Cave give support to the conclusion that this part of Europe was refugial region for this and some other small mammal species during the expansions of the ice cover, and reflect Quaternary environmental fluctuations, which were frequent and pronounced at the end of this period.

lemming; Dicrostonyx; teeth; morphometric analyses; Late Pleistocene; Romualdo's Cave; Croatia

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