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1.
A new stalk-forming diatom was observed at high relative abundances on periphytic samples collected in the Rio Negro hydrographic basin (Brazilian Amazon) and is here described using light and scanning electron microscopy. We also present ecological preferences of the new species. Eunotia amazonica sp. nov. co-dominated periphytic samples collected during the rainy seasons of 2013 and 2014 near the city of Manaus (Amazonas, Brazil). The main diagnostic feature of the new species is the stalk-forming growth form (‘Cymbella-like’) illustrated here for the first time in the genus Eunotia Ehrenberg. Previous reports on growth forms in common European databases for this genus included colonial (‘ribbon-like’) but also ‘mobile’, ‘fixed by pads’ or ‘without structures of fixation’. We demonstrated that the three dominant Eunotia species in periphytic samples from the Rio Negro all exhibited distinct ‘growth forms’ or habits: Eunotia amazonica sp. nov. (stalked), Eunotia intricans Metzeltin & Lange-Bertalot (ribbon-like) and Eunotia rabenhorstiana (Grunow) Hustedt (branched-arborescent). The high diversity of species, many of which are unknown to science, as well as the poorly known life-forms and habits of the Eunotiaceae in the region, partially prevent the use of metrics based on life-form to assess ecological changes. Generic assumptions based on robust statistical methods may obscure reality and lead to biased conclusions of diatom community changes in poorly explored regions such as Neotropical freshwater rivers, where the Eunotiaceae are largely dominant, particularly in the Amazon basin.  相似文献   

2.
Anna Mann  Annemarie Mol 《Ethnos》2013,78(5):772-788
This text is written in English so that it may reach an international academic audience. However, if all academic research comes to be outlined in English we are to lose a lot. Here, we argue this by presenting the case of schmecka. Drawing on fieldwork done in the Austrian region of Vorarlberg, we suggest that the word schmecka differs from the factual ‘flavour perception’ investigated in physiology; from the culturally informed ‘sensory experiences’ explored by anthropologists and even from the sociological ‘tasting in practice’. For one, schmecka is shared between modest good food and assembled eaters; two, it draws together the English ‘tasting’ and ‘smelling’; and three, it has positive overtones. This means that using schmecka is not just judicious when writing about ‘others’, here the people of Vorarlberg. It also, more interestingly, allows ‘us’ to write in another way: one that foregrounds valuing rather than facting.  相似文献   

3.
Lunaria annua is overviewed and its two subspecies, subsp. annua and subsp. pachyrrhiza, discussed, the latter described. Two cultivars of subsp. pachyrrhiza, ‘Corfu Blue’ and ‘Mistras’ are illustrated and described. Details of cultivation are also included.  相似文献   

4.
The respiratory organs of Amphipnous cuchia comprise a pair of aicsacs, vestigial gill filaments borne on second gill arch and vascular folds of the third gill arch. The volume of each air-sac, its surface area and its reltionship with the body weight of the fish have been determined. The air-sac is lined by a respiratory mucosa which is composed of vascular and non-vascular areas. Each vascular area, called here the ‘respiratory islet,’ studded with hundreds of vascular rosettes, which are formed of collagenous material and supported by endothelial cells. Pilaster cells are absent. The ‘islets’ are covered over by a single layer of squamous type of epithelial cells. The non-vascular areas (lanes') are the stratified part of the respiratory epithelium and contain a large number of mucous glands which secrete mainly acid mucopolysaccharides. The vascularisation of the gills have been studied by India ink injection methods. The secondary gill lamellae are absent, their place being taken up by coiled vascular loops. A quantitative estimation of haemoglobin in blood of ‘cuchia’ and other air- and water-breathing fishes have been made by colorimetric method and the results have been discussed in relation to their habit and habitats. The cranial muscles which are involved in respiration of ‘cuchia’ and the mechanics of muscle action in breathing have been described.  相似文献   

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Abstract: The palaeoloricate ‘polyplacophorans’ are an extinct paraphyletic group of basal chiton‐like organisms known primarily from their fossilized valves. Their phylogenetic placement remains contentious, but they are likely to include both stem‐group Polyplacophora and stem‐group Aplacophora. Candidates for the latter position include ‘Helminthochitonthraivensis from the Ordovician of Scotland, which we redescribe here through a combined optical and micro‐CT (XMT) restudy of the type material. The 11 specimens in the type series are all articulated, presenting partial or complete valve series as well as mouldic preservation of the girdle armature; they demonstrate a vermiform body plan. The valves are typically palaeoloricate in aspect, but differ in detail from all existing palaeoloricate genera; we hence erect Phthipodochiton gen. nov. to contain the species. The most notable feature of the fossils is the spicular girdle; this is impersistently preserved, but demonstrably wraps entirely around the ventral surface of the animal, implying that a ‘true’ (i.e. polyplacophoran like) foot was absent, although we do not exclude the possibility of a narrow solenogastre‐like median pedal groove having been present. Phthipodochiton thraivensis presents an apparent mosaic of aplacophoran and polyplacophoran features and as such will inform our understanding of the relationship between these groups of extant molluscs. An inference may also be drawn that at least some other palaeoloricates possessed an ‘armoured aplacophoran’ body plan, in contrast to the ‘limpet‐like’ body plan of extant Polyplacophora.  相似文献   

7.
Can a fragrance be revolutionary? In this commentary, the creation of two unusual, extravagant fine fragrances, ‘escentr?c01’ and ‘molecule01’, is described. In response to the fantasy components found in release notes of many recent perfume launches, both center around a single real fragrance raw material, the transparent woody aroma chemical ‘Iso E Super’ ( 1 + 2 ). The perfume ‘escentr?c01’ contains 65% of it, accompanied by Trisamber ( 3 ), red pepper, lime oil, incense and musks, while ‘molecule01’ consists exclusively of ‘Iso E Super’ ( 1 + 2 ). The elegant woody note lives here its own eccentric life – the revolution starts.  相似文献   

8.
Abstract: The palaeohistological study of the calcified internal organ of Axelrodichthys araripensis Maisey, 1986, a coelacanthiform from the Lower Cretaceous of Brazil (Crato (Aptian) and Santana (Albian) formations of the Araripe Basin), shows that the walls of this organ consist of osseous blades of variable thickness separated from each other by the matrix. This indicates that, in the living individuals, the walls were reinforced by ossified plates, probably separated by conjunctive tissue. This calcified sheath present in Axelrodichthys, as well as in other fossil coelacanths, lies in ventral position relative to the gut and its single anterior opening is located under the opercle, suggesting a direct connection with the pharynx or the oesophagus. The calcified organ of Axelrodichthys, like that of other fossil coelacanths, is here regarded as an ‘ossified lung’ and compared with the ‘fatty lung’ of the extant coelacanth Latimeria. The reinforcement of the pulmonary walls by the overlying osseous blades could be interpreted as a means of adapting volumetric changes in the manner of bellows, a necessary function for ventilation in pulmonary respiration. Other functional hypotheses such as hydrostatic and/or acoustic functions are also discussed.  相似文献   

9.
Stauntonia libera, collected as ‘KWJ 12218’ from Vietnam and cultivated by Crûg Farm Plants, is an evergreen vine with scented flowers and edible fruit. It is described and illustrated here and details of the distribution and habitat are also provided. It is a plant with horticultural potential, but remains a rarity in cultivation.  相似文献   

10.
Abstract Quediina, a mega‐diverse conventional subtribe of the rove beetle tribe Staphylinini, is remarkably species rich in the north and south temperate regions of the world. Tropical faunas of this group, and the fauna of the entire Afrotropical biogeographical region (= Ethiopian region, = sub‐Saharan Africa), in contrast, are remarkably poor. The taxonomic study of the quediine genera of Staphylinini from the Afrotropical region reveals misidentifications for many of them. Their phylogenetic study demonstrates polyphyly of Quediina and reveals a new evolutionary pattern for the entire tribe Staphylinini. In particular, the formerly quediine genera Euristus Fauvel, 1899 , Ioma Blackwelder, 1952, Natalignathus Solodovnikov, 2005 , all endemic in the Afrotropical region, belong to the non‐related ‘Staphylinina’, ‘Philonthina propria’ and ‘Tanygnathinina sensu novo’ lineages of Staphylinini, respectively. Contrary to earlier records, the genus Quedius Stephens, 1929 does not occur in Africa south of Sahara: Quedius angularis Cameron, 1948 and Quedius cinctipennis Cameron, 1951 are moved to the genus Philonthus Stephens, 1829. The same is established for the Asian genus Algon Sharp, 1874, formerly for a long time associated with Quediina: African species Algon robustus Wendeler, 1928 is moved to the genus Moeocerus Fauvel, 1899 (here in the ‘Philonthina propria’ lineage); and the misidentification of Algon africanus Bernhauer, 1915, a species that probably belongs to a new genus, is discussed. The phylogenetic affiliation of Afroquedius Solodovnikov, 2006 , a South African endemic, is still ambiguous. Overall, the formerly seen bipolar distribution pattern for the ‘Quediina’ is demonstrated to be an artefact, not a reality to explain. Historical biogeographical explanations are proposed for some of the Afrotropical endemics, partly as an attempt to apply biogeography as an external criterion for the evaluation of the new phylogenetic pattern revealed for Staphylinini. The monotypic genera Euristus and Ioma, as well as Heterothops megalops Cameron, 1959 , the only representative of this widespread genus in the Afrotropical region, are redescribed. Limits and synapomorphies of the genus Heterothops are discussed. The following new combinations and new names are proposed: Philonthus cinctipennis ( Cameron, 1951 ) comb.n. (preoccupied by Philonthus cinctipennis Fauvel, 1875), here replaced by Philonthus pseudoquedius Solodovnikov nom.n. ; Philonthus angularis ( Cameron, 1948 ) comb.n. ; Moeocerus robustus ( Wendeler, 1928 ) comb.n. [preoccupied by Moeocerus robustus (Gestro, 1881)], here replaced by Moeocerus wendeleri Solodovnikov nom.n. A lectotype is designated for Heterothops megalops Cameron, 1959 .  相似文献   

11.
The construction of a general model of animal movement using the ‘experimental components' approach ofC. S. Holling is proposed. The process of ‘movement’ is interpreted very generally as any displacement of the whole organism in space. The rationale for modelling such processes rests upon the idea that there is a basic “canonical” pattern of movement characteristic of a species moving in a homogeneous environment, which pattern is overlaid by the various directional stimuli present in more usual heterogeneous environments. The ‘canonical movement model’ is a necessary first step in construction of more realistic representations. We suggest it can be made using six components viz. the initial heading of the animal, the mean and variance of the angular displacements made by the animal as it moves, the mean and variance of the speed of the animal, and a term for the continuity of the movement. We have measured all these components in the field for the two-dimensional movement of the inter-tidal snail, Polinices incei and these results are presented here. Difficulties inherent in the measure ment of angular displacement in particular are discussed and means of resolving them proposed. The shortcomings involved in the measurements and techniques for their more detailed representation and the next steps in the proposed modelling sequence are discussed.  相似文献   

12.
The interrelationships within the clade comprised of turtles, pareiasaurs, and procolophonid-like taxa are investigated via a cladistic analysis incorporating 56 characters. A single most parsimonious tree was found (80 steps, c. i. = 0·8) in which the successive outgroups to turtles are: pareiasaurs, Sclerosaurus, lanthanosuchids, procolophonoids (=Owenetta, Barasaurus and procolophonids), and nyctiphruretians (= nycteroleterids). Thus, as suggested recently by other workers (Reisz, in Fischman, 1993) turtles are the highly modified survivors of a radiation of poorly-known reptiles commonly called ‘parareptiles’. Pareiasaurs are united with turtles on the basis of twenty unambiguous derived features which are absent in other basal amniotes (=‘primitive reptiles’) and reptiliomorph amphibians: for example, the medially located choana, enlarged foramina palatinum posterius, blunt cultriform process, fully ossified medial wall of the prootic, opisthotic-squamosal suture, lateral flange of exoccipital, loss of ventral cranial fissure, thickened braincase floor, ‘pleurosphenoid’ ossification, reduced presacral count, acromion process, trochanter major, reduced fifth pedal digit, and presence of transverse processes on most caudals. Recent phylogenetic proposals linking turtles with captorhinids, with dicynodonts, and with procolophonoids are evaluated. None of the proposed traits supporting the first two hypotheses is compelling. The procolophonoid hypotheses is supported by only one synapomorphy (the slender stapes). All other synapomorphies proposed in favour of the above groupings either occur in many other primitive amniotes, or are not primitive for turtles, or are not primitive for the proposed chelonian sister-group. Nyctiphruretus and Lanthanosuchids and nycteroleterids, often considered to be seymouriamorph amphibians, are demonstrated unequivocally to be amniotes. The ‘rhipaeosaurs’, currently considered to be pareiasaur relatives, are shown to be a heterogenous assemblage of seymouriamorphs, therapsids and nycteroleterids. The phylogeny proposed here indicates that many of the traits of the earliest known turtle, Proganochelys, previously interpreted as unique specialisations, also occur in pareiasaurs and other near outgroups of turtles, and must instead represent the primitive chelonian condition: for example, the wide parietals and the short quadrate flange of the pterygoid. The sequence of acquisition of chelonian traits is discussed: many features once thought to be diagnostic of turtles actually characterize larger groupings of procolophonomorphs, and must have evolved long before the chelonian shell appeared. These traits include most of the chelonian-pareiasaur synapomorphies listed above, and many others which characterize more inclusive groupings found in this analysis. In putting Proganochelys much closer to the main line of chelonian evolution, in elucidating the sequence of acquisition of chelonian traits, and in reducing greatly the number of differences between turtles and their nearest relatives, this study helps bridge one of the major gaps in the fossil record. The failure of previous cladistic analyses to identify correctly the nearest relatives of turtles is attributed to biased character selection, caused by an over-reliance on cranial characters deemed ‘important’ by earlier workers, and by a tendency to shoehorn ‘parareptile’ taxa into phylogenies derived from analyses restricted to ‘mainstream’ groups such as synapsids, diapsids, turtles, and ‘captorhinomorphs’. Many of the synapomorphies that resolve turtle origins are postcranial, and the three nearest outgroups to turtles are all highly bizarre groups which were dismissed as ‘too specialized’ by early workers and continued to be inadequately assessed even by workers using a cladistic framework.  相似文献   

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16.
(1) An analysis of the metazoan fauna of Nahal Soreq was made at several sampling stations from October 1970 to August 1971. Relative abundance of each species or group of species was estimated by semi-quantitative sampling, and population structures are given here in the form of percentage tables. (2) A succession of three zones, indicating three degrees of pollution, were recognized: a ‘Nematode zone’ in the most polluted waters, a ‘Chironomus zone’, where purification has progressed a little, and a ‘Proasellus (and ostracod) zone’, where purification is nearing completion. (3) These zones of indicator organisms roughly correspond to three zones classified in a ‘Saprobien System’ manner: a polysaprobic zone (Nematode zone), a mesosaprobic zone (Chironomus zone), and an oligosaprobic zone (Proasellus zone). A state of complete purification or recovery is not reached, and the purification process is stopped in the oligosaprobic condition by the disappearance of the stream underground. The other invertebrates characterizing these three zones are given. (4) A comparison is made of the saprobic zones and their corresponding fauna with findings reported elsewhere---Europe, North America and South Africa. The successional changes are generally similar to European findings with some notable absentees, and there are also some similarities with polluted South African streams. (5) Seasonal changes in species composition and the position of these species along the stream are discussed. There are small changes which appear to be a result of life cycle habits in some air-breathing dipterans and a slight change in the position of chironomids downstream, which is correlated with the winter rain floods. (6) The faunal types and numbers occurring downstream are compared with the increase in algal species diversity, dissolved oxygen and coli bacterial counts. It is suggested that the degree of pollution is the primary factor in the establishment and population build-up of any particular species, but that presence of suitable substrates, availability of food and presence of predators play a larger part where the water is cleaner.  相似文献   

17.
Jasmonates are plant hormones involved in wound and defense responses against herbivorous arthropods. Methyl jasmonate (MeJA) is used experimentally to induce defense responses in plants. In experiments outlined here we utilized a novel preference assay with unwounded plants that allowed us to study the impact of a MeJA spray on subsequent Tetranychus urticae Koch (Acari: Tetranychidae) proliferation and preference. Spraying plants with 100 μm MeJA 1 day before infestation caused mites to disperse within 2 days from treated impatiens [Impatiens wallerana Hook f., ‘Super Elfin Pink’ (Balsaminaceae)], pansy [Viola × wittrockiana Gams, ‘Imperial Beaconsfield’ (Violaceae)], and tomato [Solanum lycopersicum L., ‘Big Boy’ (Solanaceae)] plants. In addition, MeJA application reduced mite proliferation rate on impatiens and pansy by 60% (measured 22–34 days after infestation). Proteinase inhibitor (PI) assays suggested that MeJA‐induced PIs alone were not responsible for the observed results in pansy and impatiens but may have been a factor in tomato. Implications of these results in the context of MeJA‐induced resistance responses and possible directions for future research and application are discussed.  相似文献   

18.
Scleria aurantiaca Lye is described from eastern Gabon. It is superficially similar to S. nyassensis, but probably more closely related to S. adpresso‐hirta, which has a more similar nutlet and hypogynium. The scientific name is derived from the bright orange ring of the hypogynium. The fruit of S. aurantiaca has both micro‐ and nano‐papillae, which are described here for the first time. Also discussed is the water transport through surface hairs to the embryo in the fruit. Due to the restricted range of this species, it must be considered as ‘Endangered’ (EN).  相似文献   

19.
A phylogenetic analysis was conducted using morphological characters. Eleven of the 18 Caenorhabditis-species described were investigated. The polarity for character transformations was established and a cladogram and the character set of the stem species reconstructed. There are two possible positions for R. plicata. It was not possible to resolve the phylogenetic relationship of the Elegans-group, which consists of seven species, including the four best-known Caenorhabditis-species. Transformation series of characters, e.g. the structure of the precloacal lip, are presented. The evolution of a pharyngeal sleeve is discussed. For the terms caudal papilla, bursal papilla and ray are given precise definitions. Two individual rays are specified as ‘anterior dorsal’ and ‘posterior dorsal’. We present here a new case of a Rhabditis with 10 pairs of bursal papillae where one pair (no. 10) is the phasmids. Information on the geographical distribution and the ecology of the Caenorhabditis-species is given. The markedly different ecological niches of these species must be derived from a way of life in the stem species in patchily distributed decomposing organic material which necessitated a phoretic phase with waving behaviour of the dauer juveniles.  相似文献   

20.
Two new species of Parnassia, Parnassia zhengyuana M.X. Ren & J. Zhang and P. simianshanensis M.X. Ren, J. Zhang & Z.Y. Liu, have been found in mountainous areas of Chongqing City, southwest China, and are described and illustrated here. Parnassia zhengyuana is found in a limestone cave near Mt Jinfo, Nanchuan District, Chongqing City. This tiny plant has special spoon‐shaped leaves and undivided staminodes with green apices. Parnassia simianshanensis was discovered in Mt Simian, Jiangjin County, Chongqing City. This species grows along streams on red sandstones, i.e. in Danxia landform. It can be easily identified by its unique rhombic leaves and the five‐ or four‐branched staminodes. The conservation status of P. zhengyuana and P. simianshanensis are assessed respectively as ‘Critically Endangered’ (CR) and ‘VU’ (Vulnerable) according to IUCN criteria. The roles of karst and Danxia landforms in the speciation process are discussed.  相似文献   

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