Vladimír Vohralík

Mediterranean populations of the lesser white‐toothed shrew (Crocidura suaveolens group): an unexpected puzzle of Pleistocene survivors and prehistoric introductions

An earlier study revealed the strong phylogeographical structure of the lesser white‐toothed shrew (Crocidura suaveolens group) within the northern Palaearctic. Here, we aim to reconstruct the colonization history of Mediterranean islands and to clarify the biogeography and phylogeographical relationships of the poorly documented Middle East region with the northern Palaearctic. We performed analyses on 998‐bp‐long haplotypes of the mitochondrial cytochrome b gene of 143 samples collected around the Mediterranean basin, including islands and the Middle East. The analyses suggest that the Cypriot shrew belongs to the rare group of relict insular Pleistocene mammal taxa that have survived to the present day. In contrast, the Cretan, Corsican and Menorcan populations were independently introduced from the Middle East during the Holocene. The phylogeographical structure of this temperate Palaearctic species within the Middle East appears to be complex and rich in diversity, probably reflecting fragmentation of the area by numerous mountain chains. Four deeply divergent clades of the C. suaveolens group occur in the area, meaning that a hypothetical contact zone remains to be located in central western Iran.

Molecular evidence of Pleistocene bidirectional faunal exchange between Europe and the Near East: the case of the bicoloured shrew (Crocidura leucodon, Soricidae)

We sequenced 1077 bp of the mitochondrial cytochrome b gene and 511 bp of the nuclear Apolipoprotein B gene in bicoloured shrew (Crocidura leucodon, Soricidae) populations ranging from France to Georgia. The aims of the study were to identify the main genetic clades within this species and the influence of Pleistocene climatic variations on the respective clades. The mitochondrial analyses revealed a European clade distributed from France eastwards to north‐western Turkey and a Near East clade distributed from Georgia to Romania; the two clades separated during the Middle Pleistocene. We clearly identified a population expansion after a bottleneck for the European clade based on mitochondrial and nuclear sequencing data; this expansion was not observed for the eastern clade. We hypothesize that the western population was confined to a small Italo‐Balkanic refugium, whereas the eastern population subsisted in several refugia along the southern coast of the Black Sea.

The location of the Mus musculus-M.domesticus hybrid zone in the Balkans: clues from morphology

Three morphological characters were used to depict the position of the hybrid zone between two species of house mice,M. musculus Linnaeus, 1758 andM. domesticus Schwarz et Schwarz, 1943, across a vast area covering countries of the former Yugoslavia, Albania, Bulgaria and Greece. Quantitative approach based on a morphological index (MI), resembling the hybrid index widely used in allozyme-based genetic studies, was used. The zone crosses Slovenia south of the Sava River, and then follows the Dinaric Mts to Montenegro and northern Albania. Contrary to many previously published results, the zone was found to run parallel with northern borders of Albania and the former Yugoslavian Macedonia, about 150 km north of the Greek border, thus giving its course rather “shallow” appearance at this part of the Balkan Peninsula.

MULTIVARIATE MORPHOMETRICS OF APODEMUS MYSTACINUS IN THE NEAR EAST AND ITS DIVERGENCE FROM EUROPEAN A. M. EPIMELAS (MAMMALIA: RODENTIA)

Morphometric variation in Apodemus mystacinus populations from Syria and Jordan was studied and compared with those in Turkey, Greece, Bulgaria, and the former Yugoslavia. Altogether, 270 specimens of A. mystacinus were examined by multivariate procedures based on molar, skull, and body measurements. The previously reported distinctness of the European subspecies (species) epimelas and Asian mystacinus was confirmed. Asian populations are fairly homogenous. The populations from Syria and Jordan, as well as other material examined from Turkey, corresponded well with the population of the Middle Taurus Mts., Turkey (terra typica of A. m. mystacinus). The only exception was the case of a slightly different population from the Al-Duruz Mts. (S Syria). The validity of sspp. euxinus (E Pontic Mts.) and pohlei (N. Syria) was not supported by our data.

Genetic variation and phylogeography of free-living mouse species (genus Mus) in the Balkans and the Middle East

This work presents a study of the distribution and pattern of variation throughout the ranges of three free‐living mouse species of the genus Mus—M. macedonicus, M. spicilegus, and a M. cypriacus — based on sequencing of two segments of the mitochondrial DNA (mtDNA) control region. The study shows a similar level of variability in the three species and suggests their recent population expansion. The highest proportion of variation is found within populations indicating low genetic structuring. Phylogenetic analysis confirms the significant divergence of a mitochondrial lineage of M. macedonicus from Israel, recently described as a new subspecies, M. macedonicus spretoides. Conversely, no genetic hiatus is revealed between European and Asian populations of M. macedonicus macedonicus. Although phylogenetic relationships among M. spicilegus populations could not be unravelled precisely, the results suggest a recent westward expansion of the species. The mtDNA divergence between M. macedonicus and M. spicilegus is 7.3%, suggesting their split between c. 700 000 and 1 million years ago. These dates correspond with a coalescent estimate about 720 000 years ago. On the other hand, M. cypriacus appeared almost twice as divergent from the former species (4.5%) as from the latter (8.8%) suggesting a divergence of c. 430 000–610 000 years ago (coalescent ≈ 490 000 years ago) and 830 000–1.2 million years ago (coalescent ≈ 780 000 years ago), respectively. Approximate times of population expansion have also been estimated for all taxa and groups of populations. Existence of several glacial refuges and various colonization scenarios are discussed; since all estimated divergence times fall within interglacial periods it seems that climatic oscillations did not play a crucial role in the evolution of the three species.

Why Do Male House Mice Have Such Small Testes

We studied testes size in free-living and laboratory-born commensal and non-commensal populations of various Mus species (M. musculus musculus, M. m. domesticus, M. spicilegus, M. spretus, M. macedonicus, and laboratory mice). We found no apparent differences between wild-caught and laboratory-born individuals, or among commensal, non-commensal, and laboratory populations of M. musculus. There were, however, considerable differences among the species studied. The highest values of relative testes size were found in the aboriginal species M. spicilegus (4.4% and 2.9% for wild and laboratory populations, respectively), followed by those of M. macedonicus (from 1.7% to 0.9% for various samples) and M. spretus (1.5%). All thirteen samples representing various populations of Mus musculus exhibited smaller testes (0.7–1.0%), and finally the three lowest mean values came from laboratory mice (0.5–0.7%). It is very surprising that aboriginal species, in particular M. spicilegus, which is widely considered to be monogamous, have relatively larger testes than the polygynous/promiscuous M. musculus. This result is in apparent contradiction to the current views on evolutionary forces affecting testes size, and suggests that there could be another uncontrolled factor obscuring the relationship between testes size and multiple paternity. This raises a question concerning the proper interpretation of social organisation in the genus Mus.

Skull shape in thegenus Apodemus: phylogenetic conservatism and/or adaptation to local conditions

We studied morphological variation among western Palaearctic species of woodmice (genusApodemus). Twenty one dental and skull variables were measured and evaluated using multivariate statistical approaches. A total of 501 specimens of the following 9 species of wood mice were examined:A. hermonensis, A. hyrcanicus, A. uralensis (=microps),A. flavicollis, A. sylvaticus, A. epimelas, A. mystacinus, A. peninsulae, A. agrarius. Species occupying large geographic areas were represented by two or three geographically distant populations. The analyses, based both on original and size adjusted data, revealed congruence between morphological evolution and phylogenetic relationships.The integrity of major clades was supported by morphometric trees. Conspecific samples showed a clear tendency to cluster together regardless of ecological differences and geographical distances. This finding may suggest that studied traits exhibit evolutionary conservatism, and therefore are not fully determined by actual selective pressures. Besides this, we demonstrated that morphological differentiation of taxa belonging to the subgenus Sylvaemus was more pronounced in Central Europe than in the Near East. This observed phenomenon could be of adaptive nature.

A new subspecies of the Iranian Vole, Microtus irani Thomas, 1921, from Turkey

Abstract Microtus irani Thomas, 1921, is known with certainty from two localities which are separated by a gap of almost 2000 km. In this paper we describe a population from Balkusan in Turkey as a new subspecies Microtus irani karamani. In a complete sequence for cytochrome b gene (1140 bp), the new subspecies has unique mutations when compared with a sequence of M. i. irani from the type locality (Shiraz, Iran) at 32 positions, and differs in 35 mutations and a mean nucleotide divergence of 3.19% ±0.50. It has 60 acrocentric chromosomes in the diploid complement. Morphologically, M. i. karamani ssp. n. is smaller than M. i. irani, with a shallower brain-case, shallower rostrum, and shorter bullae. The new subspecies can be reliably separated from social voles occupying Turkey, Iran and adjacent regions of the Near East, by a combination of morphological, chromosomal and molecular data.

Cytogenetic and Molecular Relationships between Zarudny's Rock Shrew (Crocidura zarudnyi; Mammalia: Soricomorpha) and Eurasian Taxa

Abstract We karyotyped and sequenced 1,140 base pairs of the mitochondrial DNA cytochrome b of a specimen of Zarudnys rock shrew (Crocidura zarudnyi) from Baluchestan, southeastern Iran, to clarify its cytogenetic and molecular relationships with other Eurasian species of Crocidura. According to the karyotype (2N = 40, FN = 50), Zarudnys rock shrew belongs to the group of the lesser white-toothed shrew (C. suaveolens), which is different from other known crocidurine karyotypes, considering the combination of the diploid and fundamental number of chromosomes. Molecular results revealed that C. zarudnyi is included in a monophyletic clade with the C. suaveolens group, where it is a sister taxon to the others (mean Kimura 2-parameter distance = 9.7%).

Absolute, not relative brain size correlates with sociality in ground squirrels

The social brain hypothesis (SBH) contends that cognitive demands associated with living in cohesive social groups favour the evolution of large brains. Although the correlation between relative brain size and sociality reported in various groups of birds and mammals provides broad empirical support for this hypothesis, it has never been tested in rodents, the largest mammalian order. Here, we test the predictions of the SBH in the ground squirrels from the tribe Marmotini. These rodents exhibit levels of sociality ranging from solitary and single-family female kin groups to egalitarian polygynous harems but feature similar ecologies and life-history traits. We found little support for the association between increase in sociality and increase in relative brain size. Thus, sociality does not drive the evolution of encephalization in this group of rodents, a finding inconsistent with the SBH. However, body mass and absolute brain size increase with sociality. These findings suggest that increased social complexity in the ground squirrels goes hand in hand with larger body mass and brain size, which are tightly coupled to each other.