A POST‐SCRIPT TO THE ENIGMATIC PROTONYMPHA (DEVONIAN; NEW YORK): IS IT AN ARM OF THE ECHINODERMS?

Abstract:  A unique specimen of the supposed arm of the Middle Devonian (Givetian) starfish Foliaster transversus Blake, 1994[ Journal of Palaeontology , 68, 123–134] is shown to be closely comparable to the enigmatic organism Protonympha salicifolia , also of Devonian age, albeit slightly younger (Frasnian), and also from New York State. Similarities to starfish, or any other echinoderm, appear to be superficial. Differences from the type species of Protonympha are minor, but include the detailed structure of the transverse segments. For this reason a specific distinction is retained, and the taxon Protonympha transversa (Blake, 1994) now proposed. Enigmatic fossils such as Protonympha raised related questions of evolutionary affinity and the problems of pattern recognition. These questions may also touch on the interpretation of organic structures, such as might be returned from Mars (or further afield).     

Changes in the activity of the maturation-promoting factor during meiotic maturation and following activation of amphibian and starfish oocytes: their correlations with protein phosphorylation

Changes in the extent of protein phosphorylation and their possible correlation with changes in the activity of maturation-promoting (MPF) factor were investigated throughout meiotic maturation and following activation of amphibian and starfish oocytes. Despite several exceptions in the pattern of phosphorylation of individual proteins, high and low levels of protein phosphorylation were found to be correlated with high and low levels of MPF activity. Both the extent of protein phosphorylation and MPF activity were found to drop upon parthenogenetic activation and to cycle synchronously thereafter in the amphibian. In contrast no drop in MPF activity or in the extent of protein phosphorylation was observed following activation of starfish oocytes with ionophore A23187. This suggests that changes of protein phosphorylation and of MPF activity are rather related to the progression of the cell cycle than directly to Ca2+-dependent activation reaction. In amphibians global protein kinase activity in homogenates was found to drop with MPF activity following activation. Changes in the ratio of threonine vs serine phosphorylation were also investigated during the course of meiotic maturation and activation in both amphibian and starfish oocytes: changes in the activity of MPF were found to be better correlated with changes in threonine than serine phosphorylation.     

One Millimeter large Oocytes as a Tool to Study Hormonal Control of Meiotic Maturation in Starfish: Role of the Nucleus in Hormone-stimulated Phosphorylation of Cytoplasmic Proteins

Single nuclei (germinal vesicles) manually isolated from large oocytes of the starfish Echinaster sepositus , as well as the complementary anucleated oocytes, were used to investigate the early changes of protein phosphorylation which occur from 1-MeAde addition to germinal vesicle breakdown (GVBD). Stimulation of protein phosphorylation was already evident in the nucleus shortly after 1-MeAde addition (18 min, thus about 0.40x the time required for GVBD), although it began first in the cytoplasm. No translocation of phosphoprotein across the nuclear envelope was detected before GVBD. Presence of the nucleus is not required for the hormone to stimulate protein phosphorylation in the remaining part of the oocytetin:fact the patterns of protein phosphorylation in enucleated oocytes were found to be identical, whether enucleation was performed after or before hormonal treatment. Cytoplasm taken at the time of GVBD from maturing Echinaster oocytes induces meiotic maturation when transferred in stage VI immature oocytes of the amphibian Xenopus laevis.     

Generality of the action of various maturation-promoting factors

It has been known in amphibians and starfishes that a cytoplasmic factor called maturation-promoting factor (MPF), produced in maturing oocytes under the influence of the maturation-inducing hormones, can induce germinal vesicle breakdown (GVBD) and the subsequent process of meiotic maturation. The present study revealed that injection of cytoplasm of maturing starfish oocytes (starfish MPF) into immature sea cucumber oocytes brought about maturation of the recipients. Amphibian MPF obtained from mature oocytes of Xenopus laevis or Bufo bufo was found to induce maturation of starfish oocytes following injection. Cytoplasm taken from cleaving starfish blastomeres induced maturation when injected into immature starfish oocytes. The maturation-inducing activity of cytoplasm of starfish blastomeres changed along with the mitotic cell cycle during 1- to 4-cell stages so far tested and reached a peak just before cleaving. Furthermore, an extract of mammalian cultured cells, CHO or V-79, synchronized in M phase, induced GVBD in starfish oocytes following injection, whereas S phase extract had little activity. These facts suggest that MPF generally brings about nuclear membrane breakdown in both meiosis and mitosis, and that the nature of MPF is very similar among vertebrates and invertebrates.     

The oldest Devonian circumpolar ray-finned fish?

Actinopterygians (ray-finned fishes) are the most diverse group of living fishes, but have a sparse Devonian fossil record restricted to low palaeolatitudes. Here we report a new actinopterygian from the Paraná Basin of Brazil, which occupied a circumpolar position in the Palaeozoic. Available geological evidence supports a Middle Devonian or older age for this taxon, which shares features of the mandibular symphysis with the latest Devonian Tegeolepis. A phylogenetic analysis resolves these two as sister taxa. This new record expands the palaeogeographic distribution of Devonian ray-fins and suggests that gaps in their fossil record might be filled by exploring poorly sampled high-latitude localities within the Malvinokaffric Realm.     

A comparative analysis of global, national, and state red lists for threatened amphibians in Brazil

The knowledge about the conservation status of species is an important data for conservation biology. Therefore, threatened species lists are a powerful tool for conservation planning and prioritization. Our objective is to compare the global, the national and state red lists of amphibians in Brazil. Threatened species were categorized according to their listing in one or several of these lists. We analyzed for true inconsistencies across lists in order to evaluate practical consequences of such incongruences on amphibian conservation in Brazil. We recorded a total of 61 threatened amphibian species in Brazil (across all red lists). Only one species, Phrynomedusa fimbriata, was listed as Extinct (both in IUCN, Brazil and S?o Paulo lists). A total of eleven endemic species are listed as threatened by the global red list, but do not appear in Brazil’s national red list, which represent an inconsistence among these lists. Besides that, the threat category of Thoropa lutzi and Thoropa petropolitana, two endemic species, differ among both lists, which also represents a problem between both lists. These mismatches may be due to several reasons such as different interpretation of the criteria; different methodologies used; different data availability on species; differences in the dates of assessments processes; the assessors’ attitudes to uncertainty; outdated red lists. Harmonization among red lists permits a better picture of threatened amphibian diversity across scales and to develop global, national and state plans to complement conservation actions in order to maximize the chance of success of these initiatives.     

Testing the Relationship between Human Occupancy in the Landscape and Tadpole Developmental Stress

Amphibian population declines are widespread; the main causal factors are human related and include habitat fragmentation due to agriculture, mining, fires, and urban development. Brazil is the richest country in species of amphibians, and the Brazilian regions with the greatest amphibian diversity are experiencing relatively high rates of habitat destruction, but there are presently relatively few reports of amphibian declines. It is thus important to develop research methods that will detect deterioration in population health before severe declines occur. We tested the use of measurements of fluctuating asymmetry (FA) taken on amphibian larvae to detect anthropogenic stress. We hypothesized that greater human occupancy in the landscape might result in more stressful conditions for amphibians. We conducted this study at the Espinhaço mountain range in southeastern Brazil, using as a model an endemic species (Bokermannohyla saxicola, Hylidae). We chose two tadpole denticle rows and eye-nostril distance as traits for FA measurement. We measured percent cover of human-altered habitats in the landscape around tadpole sampling points and measured FA levels in sampled tadpoles. We found FA levels to differ among localities but found no relationship between human modification of the landscape and tadpole FA levels. Levels of FA in the traits we examined may not be strongly affected by environmental conditions, or may be affected by local variables that were not captured by our landscape-scale measures. Alternatively, populations may be genetically differentiated, affecting how FA levels respond to stress and obscuring the effects of anthropogenic disturbance.     

Prey selection and the impact of the starfish Marthasterias glacialis (L.) and other predators on the mussel Choromytilus Meridionalis (Krauss)

The diet of the starfish, Marthasterias glacialis (L.), consists of a variety of mollusc species, as well as ascidians and barnacles. Starfish densities are maximal where mussels, Choromytilus meridionalis (Krauss), are abundant and in such areas mussels form the bulk of the diet. Laboratory feeding experiments indicate that Marthasterias glacialis select mussels of particular sizes and that the length of prey taken is an increasing function of predator arm length. The time taken to consume each mussel is determined by the ratio of shell length to starfish size. The number of mussels consumed per day increases only slightly with starfish size, but because the prey taken increase in size, energy consumption is maintained at a relatively consistent 1% of predator body energy per day. Using prey selection and feeding rate data for different sized starfish, predictive three dimensional predation surfaces are developed for a natural starfish population feeding on either one or two cohort Choromytilus meridionalis populations. The models indicate that predatory effort should be concentrated on the smallest mussels when a single adult cohort is present, but on recruiting mussels just above the minimum prey size limit where two cohorts are present. Other major predators of mussels, the rock lobster, Jasus lalandii (Milne Edwards), and the whelk, Natica tecta Anton, appear to select similar size-ranges of prey to starfish, despite their differing body forms and feeding methods. Since the juveniles of all three predators can only take small mussels, predator recruitment may well depend upon the successful settlement of strong mussel cohorts. Evidence for such entrainment of predator cohorts to settlements of mussels is presented.     

A comparison of understanding of the amphibian crisis by zoo visitors across three countries

Despite the global declines in the rate of amphibians, evaluation of public understanding of the crisis has not yet been carried out. We surveyed visitors (n = 1,293) at 15 zoos in Brazil, New Zealand, and the United Kingdom, using a certainty‐based assessment method to compare visitor knowledge of the global amphibian crisis. We further analyzed zoo educational material about amphibians to explore its potential to raise awareness through amphibian‐focused environmental education. Visitors in the three countries had relatively little understanding of amphibians and the global amphibian crisis. When the degree of confidence in answering the questions (high, medium, and low) is accounted for, correct answers varied between 28% and 39%. This compared to scores of between 58% and 73% when the degree of confidence in responding was not accounted for. However, specific areas of knowledge (e.g., biology, conservation, biogeography, and conceptual ideas) varied significantly across the countries. Visitors had a weaker grasp of biogeographical and conservation issues than general amphibian biology. Zoo visitors in Brazil knew less about amphibian conservation than those in New Zealand or the United Kingdom. There was less amphibian‐focused content in educational materials in zoos in Brazil than there was in the United Kingdom. Improving information about the global amphibian crisis may increase support for future conservation actions. Outreach education is one of the most important approaches in any strategic planning for conservation of species. Amphibian‐focused environmental education at institutions such as zoos and aquaria can be a crucial intervention to support amphibian conservation worldwide.     

Bacterial epibionts and endolichenic actinobacteria and fungi in the Lower Devonian lichen Chlorolichenomycites salopensis

The charcoalified fragment of the dorsiventrally organized, internally stratified presumed green algal lichen Chlorolichenomycites salopensis from the Lower Devonian Lochkovian strata in the Welsh Borderland carries bacterial colonies on the upper surface, i.e. the cortex, and actinobacterial filaments in the medulla underneath the photobiont layer. Moreover relatively thin hyphae of presumed endolichenic fungi were found. As in extant lichens, which are best regarded as consortia with an unknown number of participants, this internally stratified, fossil thallus fragment of a presumed green algal lichen harbours a diverse microbial community.     

Okadaic acid mimics a nuclear component required for cyclin B-cdc2 kinase microinjection to drive starfish oocytes into M phase

G2-arrested oocytes contain cdc2 kinase as an inactive cyclin B-cdc2 complex. When a small amount of highly purified and active cdc2 kinase, prepared from starfish oocytes at first meiotic metaphase, is microinjected into Xenopus oocytes, it induces activation of the inactive endogenous complex and, as a consequence, drives the recipient oocytes into M phase. In contrast, the microinjected kinase undergoes rapid inactivation in starfish oocytes, which remain arrested at G2. Endogenous cdc2 kinase becomes activated in both nucleated and enucleated starfish oocytes injected with cytoplasm taken from maturing oocytes at the time of nuclear envelope breakdown, but only cytoplasm taken from nucleated oocytes becomes able thereafter to release second recipient oocytes from G2 arrest, and thus contains M phase-promoting factor (MPF) activity. Both nucleated and enucleated starfish oocytes produce MPF activity when type 2A phosphatase is blocked by okadaic acid. If type 2A phosphatase is only partially inhibited, neither nucleated nor enucleated oocytes produce MPF activity, although both do so if purified cdc2 kinase is subsequently injected as a primer to activate the endogenous kinase. The nucleus of starfish oocytes contains an inhibitor of type 2A phosphatase, but neither active nor inactive cdc2 kinase. Microinjection of the content of a nucleus into the cytoplasm of G2-arrested starfish oocytes activates endogenous cdc2 kinase, produces MPF activity, and drives the recipient oocytes into M phase. Together, these results show that the MPF amplification loop is controlled, both positively and negatively, by cdc2 kinase and type 2A phosphatase, respectively. Activation of the MPF amplification loop in starfish requires a nuclear component to inhibit type 2A phosphatase in cytoplasm.     

Reassessment of the Devonian problematicum Protonympha as another post‐Ediacaran vendobiont

Protonympha is an enigmatic fossil represented by two species from the Middle Devonian (Protonympha transversa) and Late Devonian (Protonympha salicifolia) of New York. Although interpreted in the past as a polychaete worm or starfish arm, Protonympha is not found with marine fossils, but with fossil plants. This fossil plant community was a swamp woodland of Lepidosigillaria whitei, with ground cover of Haskinsia colophylla, fringing brackish to freshwater coastal lagoons of the Catskill Delta. Protonympha shares with Ediacaran Vendobionta a quilted body of unskeletonized biopolymer that is unusually resistant to burial compaction. In overall form, Protonympha is most like the Ediacaran genus Spriggina. Protonympha has branching and tapering tubular structures radiating from the bottom. These rhizine‐like structures, thallus stratification and internal chambers revealed by petrographic thin sections suggest affinities with lichenized fungi. As for Cambrian Swartpuntia and Ordovician–Silurian Rutgersella, Protonympha may have been a post‐Ediacaran vendobiont.     

THE CUTICLE OF DREPANOPHYCUS SPINAEFORMIS,A LONG-RANGING DEVONIAN LYCOPOD FROM NEW YORK AND EASTERN CANADA

The presence of paracytic stomata and paired guard cells on specimens presumed to be Drepanophycus spinaeformis Göppert from eastern Canada and New York State supports the conclusion of Banks and Grierson that the species is not a reliable index of Lower Devonian strata. The interpretation of stomatal morphology demonstrates that the species lived in Early, Middle, and Late Devonian time and that slender specimens are distinct from zosterophylls such as Sawdonia that had anomocytic stomata and a single guard cell. Knowledge of the stomata also permits a reinterpretation of the stomatal apparatus as first described by Lang. Siegenian specimens of the genus apparently represent the oldest occurrence of paired guard cells and of paracytic stomata.     

Environmental and historical constraints on global patterns of amphibian richness

Our knowledge of the broad-scale ecology of vertebrate ectotherms remains very limited. Despite ongoing declines and sensitivity to environmental change, amphibian distributions are particularly poorly understood. We present a global analysis of contemporary environmental and historical constraints on amphibian richness, the first for an ectotherm clade at this scale. Amphibians are presumed to experience environmental constraints distinct from those of better studied endothermic taxa due to their stringent water requirements and the temperature dependence of their energetic costs and performance. Single environmental predictors set upper bounds on, but do not exclusively determine, amphibian richness. Accounting for differing regional histories of speciation and extinction helps resolve triangular or scattered relationships between core environmental predictors and amphibian richness, as the relationships' intercepts or slopes can vary regionally. While the magnitude of richness is strongly determined by regional history, within-region patterns are consistently jointly driven by water and temperature. This confirms that ecophysiological constraints extend to the broad scale. This coupling suggests that shifts in climatic regimes will probably have dramatic consequences for amphibians. Our results illustrate how the environmental and historical explanations of species richness gradients can be reconciled and how the perspectives are complements for understanding broad-scale patterns of diversity.     

Paleolatitudes in the Devonian of Brazil and the Frasnian-Famennian mass extinction

Differences in faunal composition of contemporary Devonian marine communities in Brazilian sedimentary basins suggest variation because of climatic gradients. Temperatures may have ranged from subarctic conditions in the Parana Basin, a type of Devonian Hudson's Bay, to temperate in the Amazon and adjoining basins, analogous to a modern “north Atlantic” climate. These gradients were paralleled in other parts of South America. The Malvinokaffric cold climate fauna was dominated by groups oforganisms that survived the worldwide late Devonian mass extinctions. Invertebrate groups absent in the Malvinokaffric regions of Brazil, Bolivia and Argentina (i.e. those restricted to Devonian equatorial belts of North America, Eurasia and Australia) were decimated in the late Devonian. These two parallel observations suggest that late Devonian extinction may have been the result of drastic cold spells that killed off reefal and peri-reefal life. By elimination of crucial benthic community components, the trophic structure of the shallow marine ecosystem of the time was upset. Subsequent repopulation of the Carboniferous seas was accomplished by hardy, eurythermal invertebrate taxa present in cold as well as tropical regions. Cold spells and mass mortality in very shallow waters may go some way to explain the production of the widespread black shale environments so typical of marine regressive phases in the late Devonian of the western hemisphere.     

A tale of two lineages: unexpected,long‐term persistence of the amphibian‐killing fungus in Brazil

For the past 17 years, scientists have been compiling a list of amphibian species susceptible to infection by the amphibian‐killing chytrid fungus, Batrachochytrium dendrobatidis (Bd), all over the world, with >500 species infected on every continent except Antarctica (Olson et al. 2013 ). Where Bd has been found, the impacts on amphibians has been one of two types: either Bd arrives into a naïve amphibian population followed by a mass die‐off and population declines (e.g. Lips et al. 2006 ), or Bd is present at some moderate prevalence, usually infecting many species but at apparently nonlethal intensities for a long time. In this issue of Molecular Ecology, Rodriguez et al. ( 2014 ) discover that the Atlantic Coastal Forest of Brazil is home to two Bd lineages: the Global Pandemic Lineage (Bd‐GPL) – the strain responsible for mass die‐offs and population declines – and a lineage endemic to Brazil (Bd‐Bz). Even more surprising was that both lineages have been present in this area for the past 100 years, making these the oldest records of Bd infecting amphibians. The team also described a moderate but steady prevalence of ~20% across all sampled anuran families for over 100 years, indicating that Brazil has been in an enzootic disease state for over a century. Most amphibians were infected with Bd‐GPL, suggesting this lineage may be a better competitor than Bd‐Bz or may be replacing the Bd‐Bz lineage. Rodriguez et al. ( 2014 ) also detected likely hybridization of the two Bd lineages, as originally described by Schloegel et al. ( 2012 ).     

滇东泥盆系几个含鱼层的时代和对比

从鱼化石的角度对滇东泥盆系下述含鱼地层进行了分析,并认为:1)曲靖地区下泥盆统徐家冲组与坡松冲组或四川的平驿铺组、广西的那高岭组层位相当,时代为布拉格期;其层位低于含 duyunolepids-Kueichowlepis鱼类组合的贵州乌当组或舒家坪组,后者时代为埃姆斯期。2)滇东中泥盆统含两个不同时期的含鱼层,其中含Yinosteus-Wudinolepis鱼类组合的武定地区旧城组属中泥盆统早期,该鱼类组合现仅知分布于武定地区。而中泥盆统晚期含鱼地层,在曲靖地区由下而上包括穿洞组、上双河组和海口组三个岩石组;其中穿洞组＋上双河组与武定的鱼子甸组对比,而海口组与曲靖组为同时异相;武定茶花箐组与曲靖组对比。3)文中时上述地层中的某些鱼化石的层位或鉴定作了评述或厘定。     

First Mesozoic Scutigeromorph Centipede, from the Lower Cretaceous of Brazil

The first Mesozoic scutigeromorph centipede (Myriapoda: Chilopoda), Fulmenocursor tenax gen. et sp. nov., is described from the Lower Cretaceous (Aptian) Crato Formation of north-east Brazil. Previously described fossil Scutigeromorpha are known from Dominican and Baltic amber, the Carboniferous (Westphalian D) Francis Creek Shale of Mazon Creek, Illinois, the Silurian and Devonian of Britain, and the Devonian of New York State.     

Late devonian facies inter-relationships in bordering areas of the North Atlantic and their palaeogeographic implications

Late Devonian faunal and facies relationships are examined in seven around the North Atlantic — in eastern North America, Greenland, western Europe and northwest Africa. A shallow marine (“littoral”) environment, characterized by the genus Cyrtospirifer, is distinguished from a deeper water (“bathyal”) goniatite-conodont milieu on the one hand, and from the “Old Red Sandstone” terrestial facies bearing plant an d fresh-water fish remains on the other.Current or source directions indicate that an “Acadian Divide” existed, separating west-flowing drainage systems in North America from those flowing to the east on the Afro-European side. All species of the osteolepid Latvius, and the majority of species of Glyptopomus are found on the eastern flank. Conversely, the earliest amphibian, Ichthyostega, may have been confined to the western side of the divide.Palaeogeographic reconstruction places northwest Africa fairly close to the Catskill Delta in the Late Devonian, thus accounting for the presence of an “American fauna” in the former. North—south migration of littoral faunas along the Afro-European shores was, however, apparently inhibited.     

Dr Jekyll and Mrs Hyde: Risky hybrid sex by amphibian‐parasitizing chytrids in the Brazilian Atlantic Forests

In their article in this issue of Molecular Ecology, Jenkinson et al. ( 2016 ) and colleagues address a worrying question—how could arguably the most dangerous pathogen known to science, Batrachochytrium dendrobatidis (Bd), become even more virulent? The answer: start having sex. Jenkinson et al. present a case for how the introduction into Brazil of the globally invasive lineage of Bd, BdGPL, has disrupted the relationship between native amphibians and an endemic Bd lineage, BdBrazil. BdBrazil is hypothesized to be native to the Atlantic Forest and so have a long co‐evolutionary history with biodiverse Atlantic Forest amphibian community. The authors suggest that this has resulted in a zone of hybrid Bd genotypes which are potentially more likely to cause fatal chytridiomycosis than either parent lineage. The endemic–nonendemic Bd hybrid genotypes described in this study, and the evidence for pathogen translocation via the global amphibian trade presented, highlights the danger of anthropogenic pathogen dispersal. This research emphasizes that biosecurity regulations may have to refocus on lineages within species if we are to mitigate against the danger of new, possibly hypervirulent genotypes of pathogens emerging as phylogeographic barriers are breached.