Karyological and allozyme variability of far eastern voles Microtus fortis Büchner, 1889 (Cricetidae, Rodentia) from the Russian Far East

Karyological (G-, C-, and NOR-banding) and allozyme analyses were carried out for island and continental populations of the vole Microtus fortis from the Far East of Russia. Variability of the autosome pair 7 was found. The presence of variation in the number of telomere heterochromatin blocks in the populations of Far Eastern voles was confirmed. NOR-staining of the Far Eastern vole chromosomes was carried out, showing stability of the number and the positions of the nucleolus organizer regions. Ten enzyme systems and three non-enzyme proteins (controlled in total by 25 interpretable loci) were examined in the Far Eastern vole from the island and continental populations. All of the loci were shown to be monomorphic, except for one esterase locus, which exhibited polymorphism at the intrapopulation and interpopulation levels. The issue of distribution of the Far Eastern vole subspecies is discussed. It is suggested that M. fortis pelliceus occurs not only in the Russian Far East, but also in Northern Transbaikalia.     

The palynological assemblages from the J–K boundary beds of the Bureya Basin,Russian Far East

Palynological assemblages were studied from the coal-bearing Upper Jurassic (Talanja Formation) to the Lower Cretaceous (Dublikan Formation) deposits of the Bureya Basin, Russia. The palynological assemblages from the upper part of the Talanja Formation are dominated by gymnosperms, mainly Ginkgocycadophytus (up to 40%) and conifers related to Pinaceae (up to 70%). The contribution of non-seed plants is not great, but their diversity is considerable. The miospore assemblages of the Talanja sequence are characterized by the last appearance of the spore taxa Staplinisporites pocockii, Camptotriletes cerebriformis, Camptotriletes nitida, and Cingulatisporites sanguinolentus. The palynological assemblage from the Dublikan Formation is dominated by ferns (up to 84%), represented mainly by Cyathidites and Duplexisporites. Among gymnosperms the role of Classopollis increases (making up about 20%). Another feature is the first appearance of the spore taxa Stereisporites bujargiensis, Neoraistrickia rotundiformis, Contignisporites dorsostriatus, Appendicisporites tricostatus, and Concavissimisporites asper.     

A new species of Phyllotis (Rodentia,Cricetidae, Sigmodontinae) from Tucumán province,Argentina

A new species of rodent of the genus Phyllotis is described based in cranial and external morphology, as well as morphometric data. Additionally, sequences of the mitochondrial gene cytochrome-b were used to asses the phylogenetic relationships. We have compared our specimens with all the extant species of the genus Phyllotis and also with some species of related genera, particularly with the most similar and with those that occur in the province of Tucumán and northwestern Argentina. The new species is large compared to the average size of the genus, and can be easily distinguished from all other species essentially by coloration and by cranial morphology. It is closely related to the recently described P. anitae, and these two species are, in turn, sister to P. osilae. The only two localities where the new species has been found are in the Upper Montane Forests of the southern portion of the Yungas Ecoregion, in the province of Tucumán, Argentina.     

Hibernation Records on the Surface of Incisors in Radde’s Hamster (Mesocricetus raddei,Rodentia, Cricetidae) from Dagestan

Biology Bulletin - Abstract—The lower incisors of ten hamsters from the Khunzakh region of Dagestan were studied. One hamster implanted with a temperature data logger successfully survived...     

How many times has polyploidization occurred during acipenserid evolution? New data on the karyotypes of sturgeons (Acipenseridae,Actinopterygii) from the Russian Far East

The karyology of species of sturgeon from the Russian Far East demonstrates that the karyotype of the Sakhalin sturgeon (Acipenser mikadoi) includes 262 ± 4 chromosomes with 80 biarmed chromosomes and the number of chromosome arms (NF) 342 ± 4, the karyotype of the Amur sturgeon (A. schrenckii) includes 266 ± 4 chromosomes with 92 biarmed chromosomes and NF 358 ± 4, and the karyotype of the kaluga (A. dauricus) consists of 268 ± 4 chromosomes with 100 biarmed chromosomes and NF 368 ± 4. These results prove that all western Pacific sturgeon species are from a tetraploid origin, based on a recent ploidy scale. This suggests that at least three polyploidization events have occurred during the evolution of Acipenseridae. However, if polyploid species originated by hybridization between diploid species, there may have been more polyploidization events in this group of fishes.     

Multiple autosomal polymorphism in populations of Akodon simulator simulator Thomas, 1916 from Tucumán,Argentina (Rodentia,Cricetidae)

Cytogenetic analysis was performed on twenty seven specimens of Akodon simulator simulator collected in three different localities of Tucumán Province, Argentina. Diploid number, chromosomal morphology and C and G banding patterns were studied. Eight different karyomorphs were found, with diploid numbers of 2n=38, 39, 40, 41, and 42. All individuals showed the same number of chromosomal arms (FN=42). G-bands enable to identify chromosomal pairs (1, 10, 11, 12, 13, and 14) involved in three centric fusions. C-bands revealed that the heterochromatin is located in centromeric regions of the telocentric and biarmed chromosomes. The present study allowed us to document a new example of a floating multiple Robertsonian fusion polymorphism. The data are discussed in relation to the occurrence of Robertsonian polymorphism in natural populations.

---

Resumen Polimorfismo autosómico múltiple en poblaciones de Akodon simulator simulator Thomas, 1916 de Tucumán, Argentina (Rodentia, Cricetidae). Se realizó un análisis citogenético de 27 especímenes de Akodon simulator simulator colectados en tres localidades diferentes de la provincia de Tucumán, Argentina. Se determinó el número diploide, la morfología cromosómica y los patrones de bandeo C y G. Se encotraron 8 cariomorfos differentes, con números diploides de 2n=38, 39, 40, 41, y 42. Todos los individuos presentaron el mismo número de brazos cromosómicos (FN=42). Las bandas G permitieron identificar los pares cromosómicos (1, 10, 11, 12, 13, y 14) involucrados en tres fusiones céntricas y las bandas C revelaron que la heterocromatina está localizada en las regiones centroméricas de los cromosomas telocéntricos y de los cromosomas bibraquiados. El presente estudio nos permite analizar un nuevo ejemplo de un polimorfismo robertsoniano. Los datos son discutidos en relación con la presencia de los polimorfismos robertsonianos en la naturaleza.

     

Relationship between algal communities’ species diversity and catchment of rivers in the southern Russian Far East

The relationship between algal communities’ species diversity and the catchment of rivers in the southern Russian Far East has been studied. The number of species, varieties, and forms of algae increased significantly according to the increase in the head river area up to 80–100 km²; then this number slowed down dramatically. In general, the relationship between the number of algal taxa (D) and the catchment of the river (S, km²) was described as D = 91.6S ^0.194 (R ² = 0.97).     

Identification of tannin–degrading microorganisms in the gut of plateau pikas (Ochotona curzoniae) and root voles (Microtus oeconomus)

Gut microorganisms are thought to play a role in the degradation of plant secondary metabolites in herbivores. Here, we examined the presence of tannin–degrading microorganisms in the gut of two herbivores, plateau pikas (Ochotona curzoniae) and root voles (Microtus oeconomus). Tannase activity in the feces of wild plateau pikas and root voles increased from June to August, corresponding to the increase in condensed and hydrolyzable tannin concentrations in plants during this period. Using intragastric tannic acid infusion, we found that tannase activities were significantly higher following administration of three concentrations of tannic acid than that in the control group for root voles. In contrast, for plateau pikas, animals administered tannic acid exhibited lower tannase activity in low–dose and high–dose groups than that in the control group. Tannase activities in root voles were higher than those in plateau pikas among different months and in different tannic acid infusion groups. Three tannin–degrading anaerobic strains were isolated from the cecum of plateau pikas (termed A1, A2, and A3) and root voles (termed M1, M2, and M3). 16 s rDNA sequencing assigned isolates A1 and M1 to the genus Enterobacter, A2 and M2 to the genus Shigella, and A3 and M3 to the genus Staphylococcus. These data provided the first evidence of microorganisms with tannin–degrading activity in the gut of plateau pikas and root voles. We speculated that both animals could degrade tannins in the gut, but that root voles would have a greater ability to process tannins than plateau pikas.     

Egorov’s narrow-skulled vole (Rodentia,Arvicolinae) from the Late Pleistocene of Eastern Siberia,a North American immigrant

A comparative study of the Late Pleistocene Egorov’s narrow-skulled vole from the Indigirka River basin is performed. The taxon was previously regarded as a subspecies of Microtus (Stenocranius) gregalis (Pallas, 1779). Based on a number of morphological characters, it is shown that this vole is closer to the American species Mynomes (Vocalomys) miurus (Osgood, 1901). It is proposed that Mynomes (V.) miurus egorovi (Fejgin in Baranova et Fejgin, 1980) penetrated into northeastern Siberia during the Zyryanian glacial.     

Trofosides A and B and other cytostatic steroid-derived compounds from the Far East starfish Trofodiscus über

Three new polar steroids identified as trofoside A, (20R,24S)-24-O-(3-O-methyl-beta-D-xylopyranosyl)-3beta,6alpha,8,15beta,24-pentahydroxy-5alpha-cholestane, its 22(23)-dehydro derivative (trofoside B), and 15-sulfoxy-(20R,24S)-5alpha-cholestane-3beta,6beta,8,15alpha,24-pentaol sodium salt, were isolated from Trofodiscus uber starfish extracts collected in the Sea of Okhotsk. Two known compounds, trofoside A aglycone, (20R,24S)-3beta,6alpha,8,15beta,24-pentahydroxy-5alpha-cholestane, and triseramide, (20R,24R,25S,22E)-24-methyl-3beta,6alpha,8,15beta-tetrahydroxy-5alpha-cholest-22-en-27-oic acid (2-sulfoethyl)amide sodium salt, were also found. The structures of the isolated polyoxysteroids were established from their spectra. Minimal concentrations causing degradation of unfertilized egg-cells of the sea-urchin Strongylocentrotus intermedius (C(min)) and terminating the cell division at the stage of the first division (C(min) embr.), as well as the concentrations causing 50% immobilization of sperm cells (ImC50) and inhibiting their ability to fertilize egg-cells by 50% (IC50) were determined for the isolated compounds. Of three compounds highly toxic in embryos and sea-urchin sperm cells, the polyol with a sulfo group in the steroid core was the most active; two glycosides with monosaccharide chains located at C3 and C24 atoms were less toxic. Note that all the compounds with the spermiotoxic activities differently affected the embryo development. The positions of monosaccharide residues in the core considerably influence the compound activity. For example, both mono- and double chained glycosides with the monosaccharide fragment at C3 and C24 atoms are active against sea-urchin sperm cells and embryos, whereas the C24 glycosylated trofoside A does not affect embryos and displays a poor spermiotoxicity.     

Seasonal changes in body mass, energy intake and thermogenesis in Maximowiczi’s voles (Microtus maximowiczii) from the Inner Mongolian grassland

Small mammals inhabiting temperate and arctic regions exhibit annual adaptive adjustments in physiology, anatomy, and behavior. No data on the physiology of Maximowicz’s voles (Microtus maximowiczii) are available at present. Here we examined the seasonal changes in body mass, food intake, thermogenic capacity, serum leptin and thyroid hormone levels in wild-captured individuals from Inner Mongolian grassland, China. We further examined the effects of photoperiod on these parameters. Energy intake, resting metabolic rate, nonshivering thermogenesis (NST), and serum tri-iodothyronine (T3) levels increased while serum leptin and body mass decreased in the cold seasons. Serum T3 levels were positively correlated with NST and uncoupling protein 1 (UCP1) contents in brown adipose tissue, and leptin levels were negatively correlated with energy intake and resting metabolic rate. Furthermore, laboratory data showed these changes could be induced by short photoperiod alone. Taken together, our results indicate that Maximowicz’s voles can increase thermogenic capacity and energy intake to cope with cold stress. Serum leptin seems to be involved in the regulation of energy intake and changes in T3 level may be important for the variations in NST and/or UCP1. Short photoperiod can serve as a seasonal cue for the winter acclimatization of energy balance in free-living Maximowicz’s voles.     

Scale structure variability of “forms flock” of Barbus (=Labeobarbus) intermedius and Varicorhinus jubae from the Genale River (Eastern Ethiopia)

Scales sculpture of 6 morphotypes of large African barbs Barbus (=Labeobarbus) intermedius and Varicorhinus jubae from the Genale River were described using light and scanning electron microscopy (SEM). It was found that in spite of several trends in difference macrostructural scale parameters (shape and lateral line scales number), cannot be used for identification of most forms of barbs and V. jubae of the Genale River. SEM analysis of scale microstructure of large barbs, V. jubae and V. beso has showed that the relief of the caudal field of the scales is not uniform and four main zones may be distinguished. The differences between forms and species in the relief details are weakly expressed however the studied species may be arranged in succession according to the development of specific; characters in transitional Zone II: B. intermedius (5 forms: GF, LMP, SH, LMS, LIP) > ??smallmouth scraper?? form??probable hybrid B. intermedius × V. jubae (SMS) > V. jubae > V. beso. By the development of granulation zone III the following series may be suggested: B. intermedius (5 forms: GF, LMP, SH, LMS, LIP), V. jubae > ??smallmouth scraper?? formprobable hybrid B. intermedius × V. jubae (SMS) > V. beso. By the degree of founded ??trabecular?? structure development the following series may be arranged according to the character reduction: B. intermedius (GF, LMP, SH, LMS, LIP) > ??smallmouth scraper?? form-probable hybrid B. intermedius × V. jubae (SMS) > V. jubae > V. beso. Thus in accordance with scale microstructure Varicorhinus jubae closer to Barbus (=Labeobarbus) intermedius than to V. beso.     

New data on the Cricetidae from the Miocene “Terre Rosse” of Gargano (Apulia,Italy)

The Gargano “Terre Rosse” deposits are paleokarst fissure fillings found in the Mesozoic limestone of the Apricena-Poggio Imperiale area. They are an important source of information for evolutionary and paleobiogeographic studies. The Late Miocene-Early Pliocene assemblages found in the Terre Rosse attest the complex history of endemic faunal distribution in a paleoarchipelago. Based on the cricetid samples from six distinct fissures (F15, F21a, F21b, F21c, F1, F9, NBS) stored in the Department of Earth Sciences of the University of Florence, three species of endemic cricetids are described: the small-sized Hattomys beetsi, the middle-sized Hattomys nazarii, and the large-sized Hattomys gargantua. The specimens from fissure F15 are attributed to H. beetsi, those from F21a-b to the transitional form Hattomys beetsi-nazarii, those belonging to NBS are ascribed to H. nazarii, whereas those from F1 and F9 are classified as H. gargantua. F21c is considered contaminated with material from different fissures. In line with previously published results, the analysis confirms that the endemic cricetids underwent a remarkable increase in size through time. The morphological variations show a marked trend towards increasing enamel thickness, but also the tendency of the cusps to assume a carved-in aspect. The variations of the morphological characters confirm that the three species likely belong to the same lineage.     

Defining “high quality” food resources of herbivores: the case for meadow voles (Microtus pennsylvanicus)

Summary Food availability, food utilization patterns and levels of some nutritional factors in plants were studied in 1984–85 in an old-field community supporting low to moderate densities of meadow voles (Microtus pennsylvanicus). Food choice and preference indices were positively related to levels of proteins, and negatively related to levels of total phenolics and ADL fibers in plants. High quality resources for voles were resources that had the highest amount of proteins, and the lowest level of total phenolics and ADL fibers among available plant species. There were only two plants species among the available ones that possessed these characteristics, Festuca rubra and Vicia cracca and they represented 25 to 50% of the available biomass during summer. Vole densities of up to 64 animals/ha were therefore not limited by the availability of high quality resources. Fecal analyses performed on 267 animals in 1984 and 269 voles in 1985 showed that all voles ate high quality resources. Meadow voles appear to choose foods with high protein content and low levels of digestion inhibitors, and not on the basis of caloric content or availability. These observations contradict predictions arising from current antiherbivore hypotheses and lead us to reconsider these models in light of this new evidence.     

Microbial Biofilms in the Proshchal’naya Karst Cave (Far East,Russia)

Microbiology - Effect of abiotic (composition of drip and fracture water) and biotic factors (composition and activity of microbial complexes) on biofilm formation in the Proshchal’naya karst...     

Is evolution faster at ecotones? A test using rates and tempo of diet transitions in Neotropical Sigmodontinae (Rodentia,Cricetidae)

We evaluated whether evolution is faster at ecotones as niche shifts may be needed to persist under unstable environment. We mapped diet evolution along the evolutionary history of 350 sigmodontine species. Mapping was used in three new tip‐based metrics of trait evolution – Transition Rates, Stasis Time, and Last Transition Time – which were spatialized at the assemblage level (aTR, aST, aTL). Assemblages were obtained by superimposing range maps on points located at core and ecotone of the 93 South American ecoregions. Using Linear Mixed Models, we tested whether ecotones have species with more changes from the ancestral diet (higher aTR), have maintained the current diet for a shorter time (lower aST), and have more recent transitions to the current diet (lower aLT) than cores. We found lower aTR, and higher aST and aLT at ecotones than at cores. Although ecotones are more heterogeneous, both environmentally and in relation to selection pressures they exert on organisms, ecotone species change little from the ancestral diet as generalist habits are necessary toward feeding in ephemeral environments. The need to incorporate phylogenetic uncertainty in tip‐based metrics was evident from large uncertainty detected. Our study integrates ecology and evolution by analyzing how fast trait evolution is across space.     

Multiple refugia and glacial expansions in the Tucumane–Bolivian Yungas: The phylogeography and potential distribution modeling of Calomys fecundus (Thomas, 1926) (Rodentia: Cricetidae)

The Yungas, a subtropical mountain rainforest of South America, has been little studied in relation to the evolutionary history of the large-bodied species of the genus Calomys. Particularly, two species have been synonymized: C. boliviae and C. fecundus; the first is only known from its type locality in the northern Bolivian Yungas, whereas the second is known along the Tucumane–Bolivian Yungas shared by Bolivia and Argentina. In this study, we combined a phylogeographic approach with ecological niche modeling, with samples covering most of the geographic range of C. fecundus. One mitochondrial and two nuclear genes were used for population genetic analyses. Current and paleoclimatic models were obtained. Nuclear genes resulted uninformative by retention of ancestral polymorphism with other species of Calomys. The mitochondrial marker revealed a complex network showing signals of several population expansions. Three genetic clusters in a latitudinal sense were detected, which are coincident with the three stable climatic zones estimated by current and paleoclimatic models. We determined a pattern of expansion during glacial cycles and ancestral refugia during interglacial cycles. None of the potential distribution models predicted the presence of C. fecundus in the type locality of C. boliviae. Therefore, we recommend making integrative taxonomic studies in the Bolivian Yungas, to determine whether or not C. fecundus and C. boliviae correspond to the same species.