Mole Rats Nannospalax Research Articles

Thermal biology in the Upper Galili Mountain blind mole rat (Nannospalax galili) and an overview of spalacine energetics

Several hundred mammalian species thrive in complex burrow systems, which protect them from climatic extremes and predation. At the same time, it is also a stressful environment due to low food supply, high humidity, and, in some cases, a hypoxic and hypercapnic atmosphere. To face such conditions, subterranean rodents have convergently evolved low basal metabolic rate, high minimal thermal conductance and low body temperature. Although these parameters have been intensively studied in the last decades, such information is far from being well-known in one of the most studied groups of subterranean rodents, the blind mole rats of the genus Nannospalax. The lack of information is particularly noticeable for parameters such as the upper critical temperature and the width of the thermoneutral zone.In our study, we analysed the energetics of the Upper Galilee Mountain blind mole rat Nannospalax galili and found its basal metabolic rate of 0.84 ± 0.10 mL O2×g−1 × h−1, thermoneutral zone between 28 and 35 °C, mean Tb within the zone of 36.3 ± 0.6 °C, and minimal thermal conductance equal to 0.082 mL O2×g−1 × h−1 × C−1. Nannospalax galili is a truly homeothermic rodent well adapted to face lower ambient temperatures, because its Tb was stable down to the lowest temperature measured (10 °C). At the same time, a relatively high basal metabolic rate and relatively low minimal thermal conductance for a subterranean rodent of such body mass, and the difficulty of surviving ambient temperatures slightly above upper critical temperature, indicates problems with sufficient heat dissipation at higher temperatures. This can easily lead to overheating, that is relevant mainly during the hot-dry season. These findings suggest that N. galili can be threatened by ongoing global climate change.

Reorganization of the Y Chromosomes Enhances Divergence in Israeli Mole Rats Nannospalax ehrenbergi (Spalacidae, Rodentia): Comparative Analysis of Meiotic and Mitotic Chromosomes.

The Y chromosome in mammals is variable, even in closely related species. Middle East blind mole rats Nannospalax ehrenbergi demonstrate autosomal variability, which probably leads to speciation. Here, we compare the mitotic and meiotic chromosomes of mole rats. For the first time, we studied the behavior of their sex chromosomes in the meiotic prophase I using electron microscopy and immunocytochemical analysis. Unexpectedly, the sex chromosomes of the 52- and 60-chromosome forms of mole rats showed different synaptic and recombination patterns due to distinct locations of the centromeres on the Y chromosomes. The absence of recombination in the 60-chromosome form, the asymmetric synapsis, and the short-term disturbance in the synaptic co-orientation of the telomeric regions of the X and Y chromosomes were revealed as specific features of mole rat sex bivalents. We suggest several scenarios of Y chromosome alteration in connection with species differentiation in mole rats.

Mole-rats Nannospalax leucodon and Spalax zemni in Ukraine: identification criteria and border between their ranges

Mole-rats Nannospalax leucodon and Spalax zemni in Ukraine: identification criteria and border between their ranges

A new cytotype (2n=46) of Nannospalax xanthodon from Turkey

A new cytotype was found in a population of mole rats Nannospalax xanthodon from south-eastern Anatolia, Turkey. The karyotype contained 46 chromosomes and 66 autosomal arms (11 biarmed and 11 acrocentric autosomal pairs). The X chromosome was submetacentric and the Y chromosome small subtelocentric. Distinct dark C-bands were observed on all the biarmed chromosomes and on three pairs of acrocentric autosomes. The NORs were detected on the short arms of two subtelocentric pairs of autosomes. The published data indicate considerable chromosomal variation between populations of mole rats in south-eastern Anatolia. The finding of a karyotype with a unique chromosomal number in the karyologically well-studied region of south-eastern Anatolia indicates that the karyotype structuring between mole rat populations may be even more complex than previously realised.

Cytotypes of Nannospalax xanthodon (Satunin, 1898) (Rodentia: Spalacidae) from Western Anatolia

We performed this study on the subterranean mole rat Nannospalax xanthodon (Nehring, 1898) in western Turkey and we analyzed karyotypes of 121 specimens from 54 localities. We determined that N. xanthodon has 2n = 36, NF = 70; 2n = 38, NF = 74; 2n = 40, NF = 72; 2n = 50, NF = 70; 2n = 50, NF = 74; 2n = 52, NF = 70; 2n = 56, NF = 72; and 6 different cytotypes of 2n = 60, NF = 74, 76, 78, 80, 82, 84 in the specimens analyzed from western Turkey. We filled most of the karyological gaps in western Anatolia and documented distributional areas of cytotypes.

Karyotype of Nannospalax ehrenbergi (Nehring 1898) (Rodentia: Spalacidae) in the Mosul Province, Iraq

The karyotypes of mole rats Nannospalax ehrenbergi (Nehring 1897) from two closely located populations from Mosul province, Iraq, were investigated. The karyotype of this form was 2n=52, NF= 76, NFa=72 which consists of 11 pairs of metacentric/submetacentric autosomes, and 14 pairs of acrocentric autosomes. The X chromosome was large and metacentric, whereas the Y chromosome was small and acrocentric. The species occurrence in Iraq, based on literature overview and the present study, was updated. Karyotypic data for the Nannospalax ehrenbergi from Iraq are presented for the first time.

C-heterochromatin and NORs distrubution of mole rat, Nannospalax xanthodon from Aksaray, Turkey

Abstract In this study, to clear cytogenetic characteristics of 2n = 60 chromosome form of blind mole rats Nannospalax xanthodon superspecies, we carried out conventional staining, Ag-NORs (Nucleolar Organizer Regions) staining and C-banding on the mole rat specimens obtained from 9 localities in Aksaray province, Turkey. Heteromorphic chromosomal pair was determined in Eskil populations. C-heterochromatin regions were found in centromeric region of all bi-armed autosomal pairs whereas C-heterochromatin was localized in pericentromeric areas of some acrocentric autosomes. The sex chromosomes possessed distinct pericentrometric dark C-band. Heteromorphic autosomal pair with deletion/addition of heterochromatin and euchromatin material in short arms was recorded in Eskil populations. The NORs were localized in distal areas of the euchromatic short arms in four pairs of bi-armed autosomes in all the studied populations.

Seismic Signal Use by Fossorial Mammals1

Abstract The subterranean environment is not favorable for the use of vision or the audition of airborne sounds as means of long-distance sensory perception. However, seismic vibrations have been shown to propagate at least an order of magnitude better than airborne sound between the burrow systems of the mole-rat Georychus capensis. The use of the seismic channel for communication underground is well documented for other species of bathyergids, as well as the spalacine mole-rat Nannospalax. It has recently been suggested that the golden mole Eremitalpa granti namibensis may also be sensitive to ground vibrations, in this case used in foraging in its desert habitat. In this paper, the use of seismic signals among these and other fossorial mammals is reviewed from theoretical, behavioral and anatomical standpoints. The question of whether auditory or somatosensory means are used to detect vibratory signals is examined. Attempts to explain the distribution of seismic sensitivity and communication mechanisms...

Seismic Signal Use by Fossorial Mammals

The subterranean environment is not favorable for the use of vision or the audition of airborne sounds as means of long-distance sensory perception. However, seismic vibrations have been shown to propagate at least an order of magnitude better than airborne sound between the burrow systems of the mole-rat Georychus capensis. The use of the seismic channel for communication underground is well documented for other species of bathyergids, as well as the spalacine mole-rat Nannospalax. It has recently been suggested that the golden mole Eremitalpa granti namibensis may also be sensitive to ground vibrations, in this case used in foraging in its desert habitat. In this paper, the use of seismic signals among these and other fossorial mammals is reviewed from theoretical, behavioral and anatomical standpoints. The question of whether auditory or somatosensory means are used to detect vibratory signals is examined. Attempts to explain the distribution of seismic sensitivity and communication mechanisms among fossorial mammals are considered. The potential influences of different soil type and digging methods are discussed, and it is proposed that digging mechanisms involving the head might preadapt a fossorial mammal towards the development of seismic sensitivity.