Phylogenetic relationships among cultivated <Emphasis Type="Italic">Zanthoxylum</Emphasis> species in China based on cpDNA markers

We here present a molecular phylogenetic analysis of cultivated Zanthoxylum species which have a long history of cultivation both for economic and for chemical values in China. Three cpDNA markers, including matK, rbcL, and trnL-F, were sequenced, with the goals of untangling phylogenetic relationships and inferring biogeographic origin and patterns of distribution among Zanthoxylum species. Based on three cpDNA markers, 19 haplotypes with 64 polymorphic sites in Zanthoxylum provenances were identified in our study. A low genetic differentiation (G _ST ?=?0.271, N _ST ?=?0.373) was observed within Zanthoxylum provenances. Based on phylogenetic tree and haplotype network, all 19 haplotypes were grouped into six clusters. Our results also supported the hypothesis that the so-called “Green Huajiao” belongs to the species Zanthoxylum armatum rather than Zanthoxylum schinifolium. The results also revealed that haplotypes of two cultivated species, Zanthoxylum bungeanum and Z. armatum, most probably diverged during the Late Miocene. Ancestral area reconstruction indicated that cultivated Zanthoxylum species experienced multiple long-distance dispersal events and several vicariance events and the ancestors of Zanthoxylum first colonized Yunnan and Guizhou provinces (D). Accordingly, the current disjunct distribution of Z. bungeanum and Z. armatum may represent long-distance dispersal of ancestors popularly named “Dahongpao” and “Qinghuajiao,” respectively. It is concluded that cpDNA markers may provide a new conceptual and practical opportunity to evaluate genetic diversity and to identify local cultivars of Zanthoxylum, making it a valuable source to include into potential breeding programs.     

Genetic analyses of resistance to the peach root-knot nematode (<Emphasis Type="Italic">Meloidogyne floridensis</Emphasis>) using microsatellite markers

Most commercially important rootstocks for peach [Prunus persica (L.) Batsch] had been selected for resistance to one or more of the root-knot nematode (RKN) species: Meloidogyne incognita, M. arenaria, and M. javanica. The peach root-knot nematode, M. floridensis (MF), is a relatively newly discovered threat to peach and is not controlled by resistance genes in “Nemared,” “Nemaguard,” and “Okinawa.” The “Flordaguard” peach seedling rootstock, conventionally bred to provide resistance to MF, has solely been used for low-chill peach production in Florida for over 20 years and has already shown signs of resistance breakdown. A source of high resistance to the pathogenic MF isolate (“MFGnv14”) was identified from wild peach Prunus kansuensis Rehder (Kansu peach), thereby suggesting the potential for broadening spectrum and increasing durability of resistance in peach rootstocks through interspecific hybridization with P. kansuensis. Using 12 F₂ and BC₁F₁ populations derived from crosses between Okinawa or Flordaguard peach and P. kansuensis populations, we examined the genetic control for MF resistance by identifying associated microsatellite markers and determining genomic location of the resistance locus. One microsatellite marker (UDP98-025) showed strong and consistent association with resistance based on root-galling index. The resistance locus was mapped on the subtelomeric region of linkage group 2, co-localizing with other previously reported RKN resistance genes in Prunus. Segregation of gall-index-based resistance observed in F₂ and BC₁F₁ populations is compatible with the involvement of a multiallelic locus wherein a dominant (Mf₁) or recessive (mf₃) resistance allele is inherited from P. kansuensis, and susceptibility alleles (mf₂) from peach.     

Initial growth deceleration as an immanent property of plants

A previously published sectional model of the system of tree branches (spruce) was expanded in the range (0,1) of the fractal model parameter μ, which links the value of green biomass of a “tree” to its size. The presence of branches in this range indicates the realization of green biomass in the form of photosynthe-sizing “points”, and is interpreted as endosymbiosis of cyanobacteria with protists. Using the method of box dimensionality, the parameter μ was estimated for the sets of points within an interval. The properties of the uniform and group distributions are shown to be different. For the group distribution, the trajectories of parameter μ are fundamentally different, depending on the method of point grouping, i.e., they decrease with an increase in the total number of points for a fixed number of points n _g in the groups and increase for a fixed number N _g groups. The initial endosymbiosis of cyanobacteria and “protists” is characterized by a lack of the necessary infrastructure in protists for feeding cyanobacteria and distributing their products and, thus, by a fixed number of “points” in the group. As the infrastructure of protists developed in the course of evolution, endosymbiosis tended to move towards an increased number of points in the group and, accordingly, increased μ. A special form of the dependence of parameter μ(N _g *n _g ) provides the inherent nature of the initial growth deceleration and modularity of architecture, which are occasionally observed in extant plants.     

Fine-scale differences in genetic and census population size ratios between two stream fishes

Comparing the ratio of effective number of breeders (N _b ) to adult population size (N) among closely related coexisting species can provide insights into the role of life history on N _b /N ratios and inform conservation programs towards limiting the loss of evolutionary potential in natural populations. We estimated N _b and N in two coexisting salmonid fishes (Brook trout and Atlantic salmon) for 3–4 consecutive years in two small, adjacent streams in Newfoundland, Canada, using mark-recapture (N), linkage disequilibrium (N _b(LD)), and sibship frequency approaches (N _b(Sib) ). We found that N _b /N ratios were about 20-fold greater in Atlantic salmon than in brook trout (mean 0.20, range 0.06–0.56 vs. mean 0.02, range 0.01–0.05, respectively). This difference was consistent across N _b estimators. In addition, we found that removing migrants reduced N _b : the strength of the effect was weak for N _b(LD) and much stronger for N _b(Sib). Our results highlight the importance of subtle ecological differences and gene flow in shaping N _b /N. They also provide some evidence that the linkage between demographic and evolutionary processes varies between closely related taxa and suggest that a more complete understanding of the N _b /N range across various species is an important component of conservation genetics and management.     

Hardness maximization or equalization? New insights and quantitative relations between hardness increase and bond dissociation energy

It has been overlooked that the change of hardness, η, upon bonding is intimately connected to thermochemical cycles, which determine whether hardness is increased according to Pearson’s “maximum hardness principle” (MHP) or equalized, as expected by Datta’s “hardness equalization principle” (HEP). So far the performances of these likely incompatible “structural principles” have not been compared. Computational validations have been inconclusive because the hardness values and even their qualitative trends change drastically and unsystematically at different levels of theory. Here I elucidate the physical basis of both rules, and shed new light on them from an elementary experimental source. The difference, Δη = η _mol – <η _at>, of the molecular hardness, η _mol, and the averaged atomic hardness, <η _at>, is determined by thermochemical cycles involving the bond dissociation energies D of the molecule, D ⁺ of its cation, and D ^? of its anion. Whether the hardness is increased, equalized or even reduced is strongly influenced by ΔD = 2D – D ⁺  ? D ^?. Quantitative expressions for Δη are obtained, and the principles are tested on 90 molecules and the association reactions forming them. The Wigner-Witmer symmetry constraints on bonding require the valence state (VS) hardness, η _VS, instead of the conventional ground state (GS) hardness, η _GS. Many intriguingly “unpredictable” failures and systematic shortcomings of said “principles” are understood and overcome for the first time, including failures involving exotic and/or challenging molecules, such as Be_2, B₂, O₃, and transition metal compounds. New linear relationships are discovered between the MHP hardness increase Δη _VS and the intrinsic bond dissociation energy D _i . For bond formations, MHP and HEP are not compatible, and HEP does not qualify as an ordering rule.     

The genusSaccharomyces (Meyen) Reess

The authors submit a taxonomic evaluation of an intermediate group of strains between the speciesSaccharomyces carlsbergensis Hansen andSaccharomyces cerevisiae Hansen. The material consisted of atypical strains of “bottom” brewer’s yeasts and the synonymous strainsSaccharomyces monacensis Hansen andSaccharomyces mandshuricus Saito. It was found that there were two different serological types in the speciesSaccharomyces carlsbergensis, one of which was characterized by the presence of antigen “C” and was typical for this species, while the other possessed antigen “M” and was grouped roundSaccharomyces monacensis. This second serological type merges with a group of strains which gives only one third fermentation of raffinose, so that it is actually an intermediate betweenSaccharomyces cerevisiae Hansen andSaccharomyces carlsbergensis Hansen and indicates the course of progressive development from the former species to the latter. No close similarity was found betweenSaccharomyces mandshuricus Saito and some of the strains of the transitional group or typical representatives of the two main species, and the authors therefore consider that there is some obscurity as to its synonymity withSaccharomyces carlsbergensis.     

High-throughput sequencing of <Emphasis Type="Italic">Prunus ferganensis</Emphasis> indicates that it is a geographical population of <Emphasis Type="Italic">P. persica</Emphasis>

Peach belongs to the genus Prunus, which includes Prunus persica and its relative species, P. mira, P. davidiana, P. kansuensis, and P. ferganensis. Of these, P. ferganensis have been classified as a species, subspecies, or geographical population of P. persica. To explore the genetic difference between P. ferganensis and P. persica, high-throughput sequencing was used in different peach accessions belonging to different species. First, low-depth sequencing data of peach accessions belonging to four categories revealed that similarity between P. ferganensis and P. persica was similar to that between P. persica accessions from different geographical populations. Then, to further detect the genomic variation in P. ferganensis, the P. ferganensis accession “Xinjiang Pan Tao 1” and the P. persica accession “Xia Miao 1” were sequenced with high depth, and sequence reads were assembled. The results showed that the collinearity of “Xinjiang Pan Tao 1” with the reference genome “Lovell” was higher than that of “Xia Miao 1” and “Lovell” peach. Additionally, the number of genetic variants, including single nucleotide polymorphisms (SNPs), structural variations (SVs), and the specific genes annotated from unmapped sequence in “Xia Miao 1” was higher than that in “Xinjiang Pan Tao 1” peach. The data showed that there was a close distance between “Xinjiang Pan Tao 1” (P. ferganensis) and reference genome which belong to P. persica, comparing “Xia Miao 1” (P. persica) and reference ones. The results accompany with phylogenetic tree and structure analysis confirmed that P. ferganensis should be considered as a geographic population of P. persica rather than a subspecies or a distinct species. Furthermore, gene ontology analysis was performed using the gene comprising large-effect variation to understand the phenotypic difference between two accessions. The result revealed that the pathways of gene function affected by SVs but SNPs and insertion-deletions markedly differed between the two peach accessions.     

Effective to census population size ratios in two Near Threatened Mediterranean amphibians: <Emphasis Type="Italic">Pleurodeles waltl</Emphasis> and <Emphasis Type="Italic">Pelobates cultripes</Emphasis>

Efforts to mitigate amphibian declines are hindered by a lack of information about basic aspects of their biology and demography. The effective to census population size ratio (N _e /N _c ) is one of the most important parameters for the management of wildlife populations because it combines information on population abundance and genetic diversity and helps predict population viability in the long term. Few studies have calculated this ratio in amphibians, which sometimes show low ratios, associated with a higher extinction risk. Here we integrate field-based (capture-mark-recapture studies, egg string counts) and molecular approaches (estimation of the effective number of breeders (N _b ) and the effective population size (N _e ) based on genotypes from larval cohorts and candidate parents) to produce the first estimates of the N _e /N _c and N _b /N _c ratios in two amphibians, the Iberian ribbed newt Pleurodeles waltl and the western spadefoot Pelobates cultripes. Additionally, we investigate sex-biased dispersal in both species based on direct (field observations) and indirect (genetic) evidence. Both species showed similar ratios, slightly lower in Pleurodeles (0.21–0.24) than in Pelobates (0.25–0.30). Observed displacement rates were low in both species (P. waltl?=?0.51%; P. cultripes?=?1.23%). We found no evidence for sex-biased dispersal in P. cultripes, but both direct and indirect evidences suggest a tendency for female-biased dispersal in P. waltl. We discuss differences in the genetic estimates of N _e and N _b provided by three inference methods and the implications of our findings for the management of these species, characteristic of Mediterranean wetlands in the Iberian Peninsula and listed as Near Threatened.     

On new Jurassic Rissooidea and Zygopleuroidea convergently similar to them (Gastropoda: Pectinibranchia)

A new genus, Boreomica gen. nov., is established; it comprises small-sized gastropods widespread in the Jurassic of the Russian Plate, the taxonomic position of which was ambiguously treated by previous authors. The new genus is assigned to the family Rissoidae. The species composition and stratigraphical and geographical distribution of the genus and its species are discussed. From the Jurassic of the Russian Plate, Callovian Boreomica exigua (Gerasimov, 1992), the type species of the genus, and Kimmeridgian–Volgian Boreomica undulata (Tullberg, 1881), and members of the genus without species status from the Bathonian and Upper Oxfordian are described. Conchological polymorphism of species connected with their eurybiontic characteristics is discussed. Based on the study of samples of the species B. exigua from different types of facies, two subspecies are recognized, B. exigua exigua and B. exigua arenosa subsp. nov. Finds of gastropods morphologically similar to Boreomica are discussed: Katosira? sp. from Mitta et al., 2004, “Procerithium?” volgense Gerasimov, 1955, “Eulima” pusilla Tullberg, 1881, and “Hudlestonella” caleptra sensu Gerasimov, 1992 are considered. It is concluded that E. pusilla and H. caleptra are unknown zygopleurids, Katosira? sp. is likely a poorly preserved Katosira, and “Procerithium?” volgense is represented by a mixture of several species belonging to different genera: several zygopleurid species, the rissoids Boreomica undulata and Bralitzia. Shells of P. volgense in the P.A. Gerasimov’s collection from the Craspedites nodiger Zone are described as Laevipleura sp.     

Conservation genetics of the threatened catfish <Emphasis Type="Italic">Conorhynchos conirostris</Emphasis> (Siluriformes: <Emphasis Type="Italic">incertae sedis</Emphasis>), an evolutionary relict endemic to the São Francisco River Basin,Brazil

Analysis of genetic datasets can be particularly useful in providing guidelines for conservation management of understudied species targeted by commercial activities. Here we used population genetic approaches to inform on the conservation status of the Neotropical long-nose pirá catfish, Conorhynchos conirostris. Pirá is a large migratory fish endemic to the São Francisco River Basin (SFRB). It is an evolutionarily divergent and relict species, being the sole representative of an incertae sedis family. The species is considered locally extinct in the upper and lower SFRB, listed as vulnerable on the IUCN Red List and as endangered on the Brazilian Red List (ICMBIO). Fishing prohibition has received severe criticism from middle SFRB fisheries that claim that this understudied species is relatively abundant in that region. We used information from 13 microsatellite markers and COI mitochondrial sequences to clarify the genetic diversity of this enigmatic species in the middle SFRB, to estimate contemporary effective population size (N_e), and to assess its conservation status. Results from bottleneck analyses indicated that the species has experienced recent reductions in population size, which is consistent with small estimates of contemporary N_e. The predicted amount of heterozygosity loss (H_t) in t generations ranged from 0.1152 (for an estimated N_e of 26.4; t?=?100) to 0.7573 (for an estimated N_e of 169.9; t?=?10). Our study supports the conservation status proposed by the ICMBIO to the remaining pirá population. Moreover, we highlight the need for demographic data and the re-assessment of the current IUCN classification for this evolutionary relict lineage.     

The gene pool of the Belgorod oblast population: II. “Family name portraits” in groups of districts with different degrees of subdivision and the role of migrations in their formation

The frequencies and spectra of surnames have been analyzed in groups of raions (districts) of the Belgorod oblast (region) with different degrees of population subdivision. The “family name portraits” of districts with low (0.00003 < < f*_r < 0.00022, \(\overline {f_r^ * } \) = 0.00015) and moderate (0.00023 < f*_r < 0.00042, \(\overline {f_r^ * } \) = 0.00029) inbreeding levels are similar both to each other and to the “family name portrait” of the Belgorod oblast as a whole. Districts with high subdivision levels (0.00043 < f*_r < 0.00125, \(\overline {f_r^ * } \) = 0.00072) had very distinctive surname spectra and the highest surname frequencies. Intense immigration to the Belgorod oblast significantly affects its population genetic structure, decreasing the population subdivision.     

Intestinal enterobacteria of the hibernating <Emphasis Type="Italic">Apis mellifera mellifera</Emphasis> L. bees

Dynamics of enterobacteria of normal intestinal microflora was studied in Apis mellifera mellifera L. bees hibernating under snow in the Western Urals. The cell numbers (N) of the predominant species Klebsiella oxytoca increased from 10-10⁶ CFU/bee in November 2004 to 10⁴-10⁷ CFU/bee in March 2005; its frequency of occurrence (P) increased from 92 to 100%. Increase of Providencia rettgeri (11.2004: N up to 10⁶, P 25%; 03.2005: N 10²-10⁶, P 80%) was accompanied by the substitution of Morganella morganii (11.2004: N up to 10⁶, P 25%) with Proteus vulgaris (03.2005: N up to 10⁵, P 8%). By spring, Hafnia alvei and Citrobacter sp., which are pathogenic to bees, disappeared (11.2004: N up to 10⁵, P 13 and 10%, respectively). Endophytic species Pantoea agglomerans, Leclecria sp., and other representatives of the “Enterobacter agglomerans” group were present in November and after the first emergence in spring (N up to 10⁵; November: P 15%; April: P 23%). In April, the number of enterobacteria decreased to 10⁵, and P. rettgeri became the predominant species (P 54%) instead of K. oxytoca (P 43%).     

Biotic Interactions between Two Species of Microalgae in Mixed Culture

Biotic interactions in a mixed culture of two microalgae species—Scenedesmus quadricauda (Turp.) Breb. and Monoraphidium arcuatum (Korsch.) Hind.—used in bioassay in monocultures as test objects were studied. The toxic effect of cell-free filtrates from different “age” monoculture (2, 7, 10, 15, 21, and 28 days) of S. quadricauda on the growth of the “young” test culture of M. arcuatum and, conversely, the toxic effect of cell-free filtrates from the different “age” (2, 7, 10, 15, 21, and 28 days) monoculture of M. arcuatum on the growth of the “young” test culture of S. quadricauda was evaluated. Simultaneously, the toxicity of their own filtrates of different “ages” was monitored by a test culture of each species. The interactions of the species in the mixed culture can be regarded as negative, as an antagonistic one, when both populations inhibit the growth of each other through metabolites and food resource competition, while the effect of S. quadricauda on M. arcuatum is much stronger. The main factor constraining the growth of monoculture S. quadricauda is the rapid depletion of the food resource from the medium and not the inhibition of growth by its own metabolites. The depletion of the food resources from the medium in monoculture of M. arcuatum occurs much later than in monoculture of S. quadricauda. Metabolites of S. quadricauda cause a strong inhibitory effect on the growth of M. arcuatum, and the metabolites of M. arcuatum cause a weak inhibitory effect on the growth of S. quadricauda. The filtrates of the “old” culture of S. quadricauda (21–28 days) cause the greatest inhibitory effect on cell division of M. arcuatum. The filtrates of the “old” culture of S. quadricauda (21–28 days) cause the greatest inhibitory effect on cell division of M. arcuatum. Comparative analysis of the cell number dynamics of two species, S. quadricauda and M. arcuatum, in mono- and two-species algal cultures, as well as experiments with filtrates of these monocultures, showed that the interaction of species can be explained by the food resource competition and allelopathic interaction (exometabolite effect).     

Genetic structure of diploid-polyploid complex of spined loach genus <Emphasis Type="Italic">Cobitis</Emphasis> (<Emphasis Type="Italic">Cypriniformes,Cobitidae</Emphasis>) in the Lower Danube

The extremely high diversity of spined loach biotypes in the Lower Danube has been detected by biochemical genetic investigation and cytometric analysis of 358 specimens collected in the riverbed and shallow channels. Along with two diploid species (C. elongatoides and C. “tanaitica”), six hybrid forms were revealed, namely, diploid C. elongatoides-“tanaitica”; triploid C. 2 elongatoides-“tanaitica,” C. elongatoides-2 “tanaitica,” and C. 2 elongatoides-species-1; and tetraploid C. 3 elongatoides-“tanaitica” and C. elongatoides-species-2-2 “tanaitica.” In addition, specimens with recombinant genotypes were also found. In spite of the apomictic mode of reproduction, the polyploids did not possess clonal structure, but according to the level of polymorphism and the genotype distribution, they were isomorphous to parental diploid species. Thus, in contrast to the polyploidy in Cobitids of the Dnieper, which have appeared in the basin due to the expansion, the polyploids of the Lower Danube are autochthonous and were derived by crossing with local diploid species. The process is apparently proceeds without any limitations.     

Evolution of root nodule bacteria: Reconstruction of the speciation processes resulting from genomic rearrangements in a symbiotic system

The processes of speciation and macroevolution of root nodule bacteria (rhizobia), based on deep rearrangements of their genomes and occurring in the N₂-fixing symbiotic system, are reconstructed. At the first stage of rhizobial evolution, transformation of free-living diazotrophs (related to Rhodopseudomonas) to symbiotic N₂-fixers (Bradyrhizobium) occurred due to the acquisition of the fix gene system, which is responsible for providing nitrogenase with electrons and redox potentials, as well as for oxygen-dependent regulation of nitrogenase synthesis in planta, and then of the nod genes responsible for the synthesis of the lipo-chitooligosaccharide Nod factors, which induce root nodule development. The subsequent rearrangements of bacterial genomes included (1) increased volume of hereditary information supported by species, genera (pangenome), and individual strains; (2) transition from the unitary genome to a multicomponent one; and (3) enhanced levels of bacterial genetic plasticity and horizontal gene transfer, resulting in formation of new genera—of which Mesorhizobium, Rhizobium, and Sinorhizobium are the largest—and of over 100 species. Rhizobial evolution caused by development and diversification of the Nod factor-synthesizing systems may result in either relaxed host specificity range (transition of Bradyrhizobium from autotrophic to symbiotrophic carbon metabolism in interaction with a broad spectrum of legumes) or narrowed host specificity range (transition of Rhizobium and Sinorhizobium to “altruistic” interaction with legumes of the galegoid clade). Reconstruction of the evolutionary pathway from symbiotic N₂-fixers to their free-living ancestors makes it possible to initiate the studies based on up-to-date genome screening technologies and aimed at the issues of genetic integration of organisms into supraspecies complexes, ratios of the macro- and microevolutionary mechanisms, and development of cooperative adaptations based on altruistic interaction between the symbiotic partners.     

Adaptive photosynthetic strategies of the Mediterranean maquis species according to their origin

In consideration of their origin the adaptive strategies of the evergreen species of the Mediterranean maquis were analysed. Rosmarinus officinalis L., Erica arborea L., and Erica multiflora L. had the lowest net photosynthetic rate (P_N) in the favourable period [7.8±0.6 μmol(CO₂) m^?2s^?1, mean value], the highest P_N decrease (on an average 86 % of the maximum) but the highest recovery capacity (>70 % of the maximum) at the first rainfall in September. Cistus incanus L. and Arbutus unedo L. had the highest P_N during the favourable period [15.5±5.2 μmol(CO₂) m^?2s^?1, mean value], 79 % decrease during drought, and a lower recovery capacity (on an average 54 %). Quercus ilex L., Phillyrea latifolia L., and Pistacia lentiscus L. had an intermediate P_N in the favourable period [9.2±1.3 μmol(CO2) m^?2s^?1, mean value], a lower reduction during drought (on an average 63 %), and a range from 62 % (Q. ilex and P. latifolia) to 39 % (P. lentiscus) of recovery capacity. The Mediterranean species had higher decrease in P_N and stomatal conductance during drought and a higher recovery capacity than the pre-Mediterranean species. Among the pre-Mediterranean species, P. latifoliahad the best adaptation to long drought periods also by its higher leaf mass per area (LMA) which lowered leaf temperature thus decreasing transpiration rate during drought. Moreover, its leaf longevity determined a more stable leaf biomass during the year. Among the Mediteranean species, R. officinalis was the best adapted species to short drought periods by its ability to rapidly recover. Nevertheless, R. officinalis had the lowest tolerance to high temperatures by its P_N dropping below half its maximum value when leaf temperature was over 33.6°C. R. officinalismay be used as a bioindicator species of global change.     

The Karyotype of <Emphasis Type="Italic">Amoeba borokensis</Emphasis> from a “<Emphasis Type="Italic">proteus</Emphasis>-like” Amoeba Group (Amoebozoa: Euamoebida)

The karyotype of Amoeba borokensis was studied for the first time. At the metaphase of mitosis, this species has a haploid set of chromosomes (n = 27). This is exactly half of the diploid karyotype in Amoeba proteus (strain B). At first glance, it confirms the idea that has recently appeared that one species arises from another via multiple changes in chromosome number. However, comparative cytogenetic analysis revealed that four orthologous chromosomes from haploid sets of these two species were not distinguished by the pattern of DAPI-stained bands. It shows that the genetic distance between A. proteus and A. borokensis is higher than was believed earlier and these two species have diverged from each other. Analysis of data on the life cycles of A. proteus and A. borokensis shows that a kind of so-called “cyclic polyploidy” takes place in “proteus-like” amoebae. “Cyclic polyploidy” has recently been considered as an alternative to the sexual process for genetic recombination in agamic protists from different macrotaxons.     

Foraminifera and their associations of a possibly Rhaetian section of the Nayband Formation in central Iran,northeast of Esfahan

The following paper describes the foraminiferal fauna and associated faunal assemblages of the bedded and reef carbonates of the Upper Triassic (most probably Rhaetian) Nayband Formation, which are exposed in a section south of the small town of Bagher-Abad, northeast of Esfahan. Foraminifers are extremely rare in sponge- or coral-dominated bioconstructions and in the bedded carbonates of the Nayband Formation in central Iran. Some carbonate beds are composed of bioclastic wackstone/packstone. These are exposed in the solenoporacean horizon at the uppermost part of the section. Here, the aulotortid- and trocholinid-type foraminifers are relatively abundant. The following foraminiferal taxa with different abundances were found within the carbonates of the investigated section: Trocholina umbo Frentzen, T. turris Frentzen, T. gracilis Blau, Aulotortus tumidus (Kristan-Tollmann), Aulotortus tenuis (Kristan), Aulotortus friedli (Kristan-Tollmann), Coronipora etrusca (Pirini), Semiinvoluta clari Kristan, Turrispirillina? licia variabilis Blau, Galeanella? laticarinata Al-Shaibani, Carter and Zaninetti, Ophthalmidium sp., Agathammina sp., “Sigmoilina” schaeferae Zaninetti, Planiinvoluta carinata Leischner, Planiinvoluta sp., Nubecularia sp., Endothyra sp., Paeolituonella sp. and some sessile agglutinated and nodosariid types. All mentioned taxa are very rare, except the involutinid and trocholinid types. The following species are described as new: Trocholina blaui nov. sp., Spirilina? iranica nov. sp., and Coronipora serraforma nov. sp. Trocholina blaui is usually attached to solenoporacean thalli. Four foraminiferal associations, which are named after the occurrence of the abundant species, were distinguished as Aulotortus tumidus association, Aulotortus friedli association, Trocholina umbo association, and Trocholina blaui association. Aulotortid types and Trocholina umbo were found within the bioclastic wackstone/packstone carbonates. Trocholina blaui is abundant in solenoporacean framestones. The foraminiferal association of investigated carbonates contains a mixed fauna, known from Upper Triassic–Liassic in the Tethyan realm. Carbonates of the whole investigated section are dated—due to occurrence of the genus Aulotortus, with species A. tumidus (Kristan-Tollmann), A. tenuis (Kristan), and A. friedli (Kristan-Tollmann)—as Upper Triassic (most probably Rhaetian). The “typical” foraminifers occurring in the reef biotopes in the northwestern Tethys are either missing or extremely rare in the Iranian bioconstructions.