Major Diversification Research Articles

A Gliriform Tooth from the Eocene of the Erlian Basin (Nei Mongol, China) and the Premolar Morphology of Anagalidan Mammals at a Crossroads

The middle Eocene in Nei Mongol (China) was an interval of profound faunal changes as regards the basal Glires and gliriform mammals in general. A major diversification of rodent lineages (ctenodactyloids) and more modern small-sized lagomorphs was accompanied by a decline of mimotonids (Gomphos and Mimolagus) and anagalids. The latter was an enigmatic group of basal Euarchontoglires endemic to China and Mongolia. Here, we describe the first anagalid tooth (a P4) from the Huheboerhe classic site in the Erlian Basin. The tooth, characterized by its unique morphology intermediate between mimotonids and anagalids is semihypsodont, has a single buccal root typical of mimotonids, a large paracone located anteriorly, and a nascent hypocone, characteristic of advanced anagalids. The new finding of neither an abundant nor speciose group suggests a greater diversity of anagalids in the Eocene of China. This discovery is important because it demonstrates the convergent adaptations in anagalids, possibly of ecological significance.

Codium-like taxa from the Silurian of North America: morphology, taxonomy, paleoecology, and phylogenetic affinity

AbstractA 1901 report by the Smithsonian Custodian of Paleozoic Plants noted that the nonbiomineralized taxaButhotrephis divaricataWhite, 1901,B. newliniWhite, 1901, andB. lesquereuxiGrote and Pitt, 1876, from the upper Silurian of the Great Lakes area, shared key characteristics in common with the extant green macroalgaCodium. A detailed reexamination of theseCodium-like taxa and similar forms from the lower Silurian of Ontario, New York, and Michigan, including newly collected material ofThalassocystis striataTaggart and Parker, 1976, aided by scanning electron microscopy and stable carbon isotope analysis, provides new data in support of an algal affinity. Crucially, as withCodium, the originally cylindrical axes of all of these taxa consist of a complex internal array of tubes divided into distinct medullary and cortical regions, the medullary tubes being arranged in a manner similar to those of livingPseudocodium. In view of these findings, the three study taxa originally assigned toButhotrephis, together withChondrites verusRuedemann, 1925, are transferred to the new algal taxonInocladusnew genus, thereby establishingInocladus lesquereuxinew combination,Inocladus newlininew comb.,Inocladus divaricatanew comb., andInocladus verusnew comb. Morphological and paleoecological data point to a phylogenetic affinity forInocladusn. gen. andThalassocystiswithin theCodium-bearing green algal order Bryopsidales, but perhaps nested within an extinct lineage. Collectively, this material fits within a large-scale pattern of major macroalgal morphological diversification initiated in concert with the Great Ordovician Biodiversification Event and apparently driven by a marked escalation in grazing pressure.UUID:http://zoobank.org/97c5c737-b291-41a2-aceb-f398cac9537a

Structural Changes and Quality of Women’s Labour in India

The primary objective of this paper is to look at the trends and pattern of changes in women’s employment structure over years (1983–2018) consequent upon the structural changes in the Indian economy. It also attempts to analyse the quality of women’s labour in terms of select parameters. The study finds that there is neither quantitative nor qualitative improvement in women’s employment over time on account of structural changes in the economy. There is no ‘U’ curve of female labour supply in response to GDP growth and expansion of female literacy, implying that economic growth has not generated adequate jobs for women. It also signifies that women’s entry or exit of labour market is influenced by non-economic factors also. There is no major occupational diversification in women’s employment despite structural shift of the economy from primary to tertiary sector. Agriculture is still the leading sector in women’s employment. The study further reveals that the quality of women’s labour is poor. Overcrowding of workforce in agriculture largely as wage labourers, lower earnings, poor literacy levels, large-scale informal employment and most self-employment in the form of unpaid work are indications of women’s disadvantaged position in the labour market.

Evolutionary epidemiology of Streptococcus iniae: Linking mutation rate dynamics with adaptation to novel immunological landscapes

Pathogens continuously adapt to changing host environments where variation in their virulence and antigenicity is critical to their long-term evolutionary success. The emergence of novel variants is accelerated in microbial mutator strains (mutators) deficient in DNA repair genes, most often from mismatch repair and oxidized-guanine repair systems (MMR and OG respectively). Bacterial MMR/OG mutants are abundant in clinical samples and show increased adaptive potential in experimental infection models, yet the role of mutators in the epidemiology and evolution of infectious disease is not well understood. Here we investigated the role of mutation rate dynamics in the evolution of a broad host range pathogen, Streptococcus iniae, using a set of 80 strains isolated globally over 40 years. We have resolved phylogenetic relationships using non-recombinant core genome variants, measured in vivo mutation rates by fluctuation analysis, identified variation in major MMR/OG genes and their regulatory regions, and phenotyped the major traits determining virulence in streptococci. We found that both mutation rate and MMR/OG genotype are remarkably conserved within phylogenetic clades but significantly differ between major phylogenetic lineages. Further, variation in MMR/OG loci correlates with occurrence of atypical virulence-associated phenotypes, infection in atypical hosts (mammals), and atypical (osseous) tissue of a vaccinated primary host. These findings suggest that mutators are likely to facilitate adaptations preceding major diversification events and may promote emergence of variation permitting colonization of a novel host tissue, novel host taxa (host jumps), and immune-escape in the vaccinated host.

Late Ordovician mass extinction caused by volcanism, warming, and anoxia, not cooling and glaciation: REPLY

The Ordovician saw major diversification in marine life abruptly terminated by the Late Ordovician mass extinction (LOME). Around 85% of species were eliminated in two pulses 1 m.y. apart. The first pulse, in the basal Hirnantian, has been linked to cooling and Gondwanan glaciation. The second pulse, later in the Hirnantian, is attributed to warming and anoxia. Previously reported mercury (Hg) spikes in Nevada (USA), South China, and Poland implicate an unknown large igneous province (LIP) in the crisis, but the timing of Hg loading has led to different interpretations of the LIP-extinction scenario in which volcanism causes cooling, warming, or both. We report close correspondence between Hg, Mo, and U anomalies, declines in enrichment factors of productivity proxies, and the two LOME pulses at the Ordovician-Silurian boundary stratotype (Dob's Linn, Scotland). These support an extinction scenario in which volcanogenic greenhouse gases caused warming around the Katian-Hirnantian boundary that led to expansion of a preexisting deepwater oxygen minimum zone, productivity collapse, and the first LOME pulse. Renewed volcanism in the Hirnantian stimulated further warming and anoxia and the second LOME pulse. Rather than being the odd-one-out of the "Big Five" extinctions with origins in cooling, the LOME is similar to the others in being caused by volcanism, warming, and anoxia.

Late Ordovician mass extinction caused by volcanism, warming, and anoxia, not cooling and glaciation

Abstract The Ordovician saw major diversification in marine life abruptly terminated by the Late Ordovician mass extinction (LOME). Around 85% of species were eliminated in two pulses 1 m.y. apart. The first pulse, in the basal Hirnantian, has been linked to cooling and Gondwanan glaciation. The second pulse, later in the Hirnantian, is attributed to warming and anoxia. Previously reported mercury (Hg) spikes in Nevada (USA), South China, and Poland implicate an unknown large igneous province (LIP) in the crisis, but the timing of Hg loading has led to different interpretations of the LIP-extinction scenario in which volcanism causes cooling, warming, or both. We report close correspondence between Hg, Mo, and U anomalies, declines in enrichment factors of productivity proxies, and the two LOME pulses at the Ordovician-Silurian boundary stratotype (Dob’s Linn, Scotland). These support an extinction scenario in which volcanogenic greenhouse gases caused warming around the Katian-Hirnantian boundary that led to expansion of a preexisting deepwater oxygen minimum zone, productivity collapse, and the first LOME pulse. Renewed volcanism in the Hirnantian stimulated further warming and anoxia and the second LOME pulse. Rather than being the odd-one-out of the “Big Five” extinctions with origins in cooling, the LOME is similar to the others in being caused by volcanism, warming, and anoxia.

The valid nomen for the tree frog (genus Hyla) of Tunisia and Eastern Algeria.

Mediterranean tree frogs, Hyla gr. meridionalis Boettger, 1874 (Anura: Hylidae) are widespread around the Western Mediterranean Basin, where they naturally occur across the Maghreb (Morocco, Algeria, Tunisia). Individuals of diverse Moroccan origins have been introduced and have expanded throughout the Iberian Peninsula, southern France and northern Italy (Liguria), but also on the Canary and Balearic archipelagos (Recuero et al. 2007; Dufresnes et al. 2019). Early molecular studies uncovered several mitochondrial lineages and suggested a major cryptic diversification within this taxon, with Tunisian and eastern Algerian (Numidia) populations carrying deeply divergent haplotypes compared with the rest of the range (Recuero et al. 2007; Stöck et al. 2008; Stöck et al. 2012). While intron markers showed little differentiation (Stöck et al. 2008; Stöck et al. 2012), genome-wide data obtained from RAD-sequencing have supported the deep split suspected from mtDNA (Dufresnes et al. 2018).

Do major host shifts spark diversification in butterflies?

The Escape and Radiate Hypothesis posits that herbivorous insects and their host plants diversify through antagonistic coevolutionary adaptive radiation. For more than 50 years, it has inspired predictions about herbivorous insect macro‐evolution, but only recently have the resources begun to fall into place for rigorous testing of those predictions. Here, with comparative phylogenetic analyses of nymphalid butterflies, we test two of these predictions: that major host switches tend to increase species diversification and that such increases will be proportional to the scope of ecological opportunity afforded by a particular novel host association. We find that by and large the effect of major host‐use changes on butterfly diversity is the opposite of what was predicted; although it appears that the evolution of a few novel host associations can cause short‐term bursts of speciation, in general, major changes in host use tend to be linked to significant long‐term decreases in butterfly species richness.

Changes in world patterns of wild edible mushrooms use measured through international trade flows

International trade in edible wild mushrooms has increased spectacularly in recent years. Data point to structural changes in world markets in the purchase and sale of this non-wood forestry resource, which is becoming increasingly important in the society of many countries. The reasons why countries are exchanging these harvested products seem to be changing, making it necessary to interpret such changes on the basis of alternative explanations of the theory of international trade. The present research offers a world-wide study of these changes, analyzing the development of intra-industry trade indices of edible wild mushrooms from a wide array of countries, using foreign commercial transaction data from the United Nations Organization. The main results show that what is driving these changes seems to be the shift in world demand for these products, with changes in consumption habits that entail a major diversification in demand.

FARM DIVERSIFICATION IN THE CENTRAL HIGHLANDS OF ETHIOPIA. PATTERNS, DETERMINANTS AND ITS EFFECT ON HOUSEHOLD INCOME

Crop-livestock production is the major farming system in the highlands of Ethiopia. This study aimed to describe crop-livestock diversification pattern, examine determinants of diversification patterns, and evaluate effects of diversification on household income. Principal component analysis (PCA), seemingly unrelated regression (SUR) and ordinary least square (OLS) regression models were employed. Five major crop-livestock diversification patterns: sheep and goat, staple crops, chicken, vegetables, and animal feed-based farming were identified. The SUR model revealed that sex, education, income, extension contact, land size, market and road distance, irrigated land, and household size were significant factors that influence crop-livestock diversification patterns. It is also found that sheep and goat, vegetable, and chicken-based farming were significant production patterns that had positive effects on household income. We suggest that adoptive and adaptive agricultural practices such as small-scale irrigation, chicken rearing and sheep-based production patterns are the most potential farming systems in the highlands of Ethiopia.

A novel taxon selection method, aimed at minimizing recombination, clarifies the discovery of a new sub-population of Helicobacter pylori from Australia.

We present a novel method for taxon selection, the aim being to minimize problems arising from highly recombinant species such as Helicobacter pylori. Helicobacter pylori has accompanied modern‐human migration out of Africa and is marked by a phylogeographic strain distribution, which has been exploited to add an extra layer of information about human migrations to that obtained from human sources. However, H. pylori's genome has high sequence heterogeneity combined with a very high rate of recombination, causing major allelic diversification across strains. On the other hand, recombination events that have become preserved in sub‐populations are a useful source of phylogenetic information. This creates a potential problem in selecting representative strains for particular genetic or phylogeographic clusters and generally ameliorating the impact on analyses of extensive low‐level recombination. To address this issue, we perform multiple population structure‐based analyses on core genomes to select exemplar strains, called ‘quintessents’, which exhibit limited recombination. In essence, quintessent strains are representative of their specific phylogenetic clades and can be used to refine the current MLST concatenation‐based population structure classification system. The use of quintessents reduces the noise due to local recombination events, while preserving recombination events that have become fixed in sub‐populations. We illustrate the method with an analysis of core genome concatenations from 185 H. pylori strains, which reveals a recent speciation event resulting from the recombination of strains from phylogeographic clade hpSahul, carried by Aboriginal Australians, and hpEurope, carried by some of the people who arrived in Australia over the past 200 years. The signal is much clearer when based on quintessent strains, but absent from the analysis based on MLST concatenations.

Local Differentiation in Diversification Challenges in Eleven Coastal Villages in Iloilo Province, Philippines

Diversification in rural coastal areas has been promoted for two major reasons: reducing overfishing and increasing living standards. This article investigates diversification efforts in light of coastal squeezes in central Philippines. It presents evidence from 11 coastal villages in Iloilo Province, all of these communities are confronted with overfishing, poverty and environmental change. The empirical focus is on the impact of external support as well as remittances from overseas relatives. Three results emerge. First, the impact depends on initial intra-village conditions; presuming that fishing associations are the natural go-to stakeholders can be counterproductive. Second, more attention should be paid to transforming short-term, exogenous interventions into longer-term, endogenous capabilities. Third, unlike for households with higher levels of human capital, remittances do not constitute a major diversification strategy for fisher folk. Avenues for further research are the relationships between social capital and intra-village inequality and the interrelated nature of livelihood capitals.

Unambivalent alignment: Japan’s China strategy, the US alliance, and the ‘hedging’ fallacy

AbstractThis article examines whether the Asia-Pacific region’s geopolitical vicissitudes are causing Japan to ‘hedge’ against deepening uncertainty and risk through major strategic realignments or diversification of security and economic ties, as the original hedging literature would expect. It examines trends since 2009 in three domains fundamental to identifying whether shifts are underway in Japan’s strategic orientation vis-à-vis China: security policy (primary), trade/investment, and public opinion. Despite deepening uncertainty (and volatility), especially in ‘the Trump era’, this study finds negligible evidence of hedging behavior: e.g., realigning toward Beijing or adopting a ‘middle position’, much less developing any meaningful security ties with China. Rather, contemporary trends point in the opposite direction: Japan’s China strategy primarily centers on strengthening indigenous deterrence capabilities, bolstering the US–Japan alliance, and diversifying regional security ties beyond Beijing. Even the latter, somewhat paradoxically, aims to deepen ties with Washington and to keep it actively engaged in regional affairs.

Diaphorocetus poucheti (Cetacea, Odontoceti, Physeteroidea) from Patagonia, Argentina: one of the earliest sperm whales

Sperm whales (Physeteroidea) are the basal-most surviving lineage of odontocetes, represented today by just three highly specialized, deep-diving suction feeders. By contrast, extinct sperm whales were relatively diverse, reflecting a major Miocene diversification into various suction feeding and macroraptorial forms. The beginnings of this diversification, however, remain poorly understood. The Atlantic coast of South America provides a crucial window into early physeteroid evolution and has yielded some of the oldest species known from cranial material, Idiorophus patagonicus and Diaphorocetus poucheti – both of which are in need of re-description and phylogenetic reappraisal. Here, we re-examine Diaphorocetus in detail and, in light of its complex taxonomic history, declare it a nomen protectum. Phylogenetically, the species forms part of a polytomy including ‘Aulophyseter’ rionegresis and the two crown lineages (Physeteridae and Kogiidae) and demonstrates that facial asymmetry and a clearly defined supracranial basin have characterized this lineage for at least 20 Ma. With a total body length of 3.5–4 m, Diaphorocetus is one of the smallest physeteroids yet known. Its cranial morphology hints at an intermediate raptorial/suction feeding strategy and it has a moderately developed spermaceti organ and junk.

PS1147 SPATIAL HETEROGENEITY IN CHRONIC LYMPHOCYTIC LEUKAEMIA ANALYSED BY WHOLE‐GENOME/EXOME SEQUENCING AT DIAGNOSIS

Background:Chronic lymphocytic leukaemia (CLL) is characterised by the accumulation of neoplastic B cells in peripheral blood (PB), lymph nodes (LN) and bone marrow. CLL cells recirculate from PB to LN where the crosstalk with the microenvironment favours their maintenance and proliferation. Whole‐genome/exome sequencing (WGS/WES) studies focusing on samples from PB have described the mutational landscape of CLL uncovering a significant intra‐ and inter‐patient heterogeneity. However, the degree of spatial heterogeneity in CLL patients at diagnosis is largely unknown.Aims:We set up to dissect the spatial heterogeneity in fifteen CLL patients at diagnosis.Methods:Synchronous PB and LN DNA samples from fifteen CLL cases were analysed by WGS (n = 2) or WES (n = 13). Eight cases were IGHV mutated. Single nucleotide variants (SNVs) and short insertions and deletions (indels) were extracted from WGS/WES. Copy number alterations (CNA) were analysed from sequencing data and compared to SNP6.0 arrays. Structural variants (SV) were assessed in the two cases with WGS. The subclonal architecture of the tumour in PB and LN was reconstructed to asses for differences in the topographic representation of clones.Results:The two cases studied by WGS had 3539 and 2087 mutations, and 98.7% and 95.1% of them were shared by the PB and LN in each patient, respectively. Both cases also shared all CNA and SV in both sites. More than 75% of the mutations identified were clonal and found in both compartments. However, we identified the presence of 3 subclonal populations in each patient. In the first patient, the three subclones were equally represented in PB and LN with a clear pattern of linear evolution. The second patient showed a branching evolution with differences in the representation of two subclones (115 and 287 specific mutations, respectively) found at 7% and 47% of cancer cell fraction (CCF) in PB and at 33% and 19% of CCF in LN, respectively. The WES of the 13 cases identified a total of 49 CNA and 789 coding, splice site or UTR mutations. CNA were always shared at similar CCF between PB and LN in all cases. Regarding gene mutations, 3 cases shared 100% of alterations between PB and LN, 9 cases shared 80–95% (mean 90.5%) mutations, and only one patient had a major diversity in PB and LN (only 57% shared in both sites). Location‐specific mutations were virtually always present in small subclones (CCF < 30%), none was recurrent, and only SETD2 was previously recognised as a CLL driver. Considering the subclonal representation of the shared mutations, 5 (38%) patients had marked differences between PB and LN. The main pattern observed in 4 cases was the presence of a larger subclone in the PB only representing a small subfraction in the LN. Mutated genes in these PB predominant subclones were RICTOR (involved in PI3K‐AKT‐mTOR pathway), DIAPH3 (correlated with cell growth and migration), NPAT (involved in cell cycle and related to CLL pathogenesis), STAT1 (related to CLL differentiation and growth) or EPHA7 (Ras/MAPK signalling). No topographic differences were observed for mutations in known driver genes such as NOTCH1, TP53, ATM, SF3B1, IRF4 and DDX3X.Summary/Conclusion:Most mutations are shared between PB and LN of CLL patients at diagnosis. However, a significant fraction of patients showed marked differences in the abundance of small subclones carrying mutations in genes related to cell growth, migration and BCR signalling between PB and LN. No major spatial diversification seems to occur in known CLL driver genes and CNA between PB and LN at diagnosis.

Dispersal limitations and historical factors determine the biogeography of specialized terrestrial protists

Recent studies show that soil eukaryotic diversity is immense and dominated by micro-organisms. However, it is unclear to what extent the processes that shape the distribution of diversity in plants and animals also apply to micro-organisms. Major diversification events in multicellular organisms have often been attributed to long-term climatic and geological processes, but the impact of such processes on protist diversity has received much less attention as their distribution has often been believed to be largely cosmopolitan. Here, we quantified phylogeographical patterns in Hyalosphenia papilio, a large testate amoeba restricted to Holarctic Sphagnum-dominated peatlands, to test if the current distribution of its genetic diversity can be explained by historical factors or by the current distribution of suitable habitats. Phylogenetic diversity was higher in Western North America, corresponding to the inferred geographical origin of the H.papilio complex, and was lower in Eurasia despite extensive suitable habitats. These results suggest that patterns of phylogenetic diversity and distribution can be explained by the history of Holarctic Sphagnum peatland range expansions and contractions in response to Quaternary glaciations that promoted cladogenetic range evolution, rather than the contemporary distribution of suitable habitats. Species distributions were positively correlated with climatic niche breadth, suggesting that climatic tolerance is key to dispersal ability in H.papilio. This implies that, at least for large and specialized terrestrial micro-organisms, propagule dispersal is slow enough that historical processes may contribute to their diversification and phylogeographical patterns and may partly explain their very high overall diversity.

The evolutionary history of the Cape hare (Lepus capensis sensu lato): insights for systematics and biogeography.

Inferring the phylogeography of species with large distributions helps deciphering major diversification patterns that may occur in parallel across taxa. Here, we infer the evolutionary history of the Cape hare, Lepus capensis sensu lato, a species distributed from southern Africa to Asia, by analyzing variation at 18 microsatellites and 9 DNA (1 mitochondrial and 8 nuclear) sequenced loci, from field and museum-collected samples. Using a combination of assignment and coalescent-based methods, we show that the Cape hare is composed of five evolutionary lineages, distributed in distinct biogeographic regions-north-western Africa, eastern Africa, southern Africa, the Near East and the Arabian Peninsula. A deep phylogenetic break possibly dating to the Early Pleistocene was inferred between the African and Asian L. capensis groups, and the latter appear more closely related to other Eurasian hare species than to African Cape hares. The inferred phylogeographic structure is shared by numerous taxa distributed across the studied range, suggesting that environmental changes, such as the progressive aridification of the Saharo-Arabian desert and the fluctuations of savannah habitats in Sub-Saharan Africa, had comparable impacts across species. Fine-scale analyses of the western Sahara-Sahel populations showed rich fragmentation patterns for mitochondrial DNA but not for microsatellites, compatible with the environmental heterogeneity of the region and female philopatry. The complex evolutionary history of L. capensis sensu lato, which possibly includes interspecific gene flow, is not reflected by taxonomy. Integrating evolutionary inference contributes to an improved characterization of biodiversity, which is fundamental to foster the conservation of relevant evolutionary units.

Speciation in protists: Spatial and ecological divergence processes cause rapid species diversification in a freshwater chrysophyte.

Although eukaryotic microorganisms are extremely numerous, diverse and essential to global ecosystem functioning, they are largely understudied by evolutionary biologists compared to multicellular macroscopic organisms. In particular, very little is known about the speciation mechanisms which may give rise to the diversity of microscopic eukaryotes. It was postulated that the enormous population sizes and ubiquitous distribution of these organisms could lead to a lack of population differentiation and therefore very low speciation rates. However, such assumptions have traditionally been based on morphospecies, which may not accurately reflect the true diversity, missing cryptic taxa. In this study, we aim to articulate the major diversification mechanisms leading to the contemporary molecular diversity by using a colonial freshwater flagellate, Synura sphagnicola, as an example. Phylogenetic analysis of five sequenced loci showed that S.sphagnicola differentiated into two morphologically distinct lineages approximately 15.4 million years ago, which further diverged into several evolutionarily recent haplotypes during the late Pleistocene. The most recent haplotypes are ecologically and biogeographically much more differentiated than the old lineages, presumably because of their persistent differentiation after the allopatric speciation events. Our study shows that in microbial eukaryotes, species diversification via the colonization of new geographical regions or ecological resources occurs much more readily than was previously thought. Consequently, divergence times of microorganisms in some lineages may be equivalent to the estimated times of speciation in plants and animals.

Acanthochaetetes huauclillensis nov. sp. (Porifera: Demospongiae) from the Lower Cretaceous of Oaxaca, Mexico, and its palaeoecological, palaeobiogeographic and stratigraphic implications

A new species of chaetetid demosponge, Acanthochaetetes huauclillensis nov. sp., is described from the Upper Hauterivian to Lower Barremian of Santiago Huauclilla, Oaxaca State, Southern Mexico. The presence of tylostyle spicule pseudomorphs allowed its assignment to the Demospongiae. Criteria which allowed the proposal of this new taxon were: the presence of a scalariform arrangement of tabulae in adjacente calicles, which is observable in longitudinal section and the dimensions of calicles and tabulae in cross and longitudinal sections. These two characters make Acanthochaetetes huauclillensis nov. sp. unique among Acanthochaetetidae.The finding of microbialites growing on top of specimens of Acanthochaetetes huauclillensis nov. sp, in addition to their association to rudist faunas and the lack of associated algae allow the determination of its palaeoecological settings as coming from a cryptic reef-like environment.Further assessements include the palaeogeographic implications of this finding, which extends the distribution of ancient Acanthochaetetidae to the Western Tethyan Realm. The westward broadening of the distribution area of this family would have thus allowed its diversification and thus the development of a new species, in addition to filling the hiatuses in occurrence between the Oxfordian (oldest record for Acanthochaetetidae) and the Lower Albian, when they started their major diversification.

Korean media discourse on international education

ABSTRACTThis paper analyses the representation of international education in the Korean print media, by comparing texts produced by the leading conservative (Chosun) and progressive (Hankyoreh) newspapers in 1997 and 2014 (N = 271 articles). We find a major expansion and diversification of media articles on international education, including rising numbers of articles mentioning non-traditional destinations (beyond USA and UK), written or shaped by non-traditional media producers (i.e., educational agents), and including individual-utilitarian and positive themes. We quantify, and find statistically significant correlations among, three key variables (destination, media producer, discourse theme). Articles mentioning non-traditional destinations are more likely to be written or shaped by agents than by journalists only. Articles mentioning non-traditional destinations and articles written or shaped by agents include relatively more positive and individual-utilitarian themes (but not more individual-expressive themes) than do articles not mentioning non-traditional destinations and articles written by journalists only. Theoretically, we link the evolution of media discourse to neo-liberal structural and ideological changes that encourage market competition and consumer choice.