The external morphology of two bucephalid digenean parasites of Conger conger (Linnaeus) (Congridae, Anguilliformes) caught northwest of the Iberian Peninsula, Prosorhynchus crucibulum (Rudolphi, 1819) Odhner, 1905 and P. aculeatus Odhner, 1905, were studied using scanning electron microscopy (SEM). SEM techniques elucidated new external morphological details, mainly relating to the tegument and protruding organs, such as, in P. crucibulum, a papilla-like structure associated with the pharynx and, in P. aculeatus, the cirrus. The tegument bears scale-like spines, which in both species are arranged quincuncially. The spines of P. crucibulum are wider than long and cover the major part of the body and rhynchus. However, no spines were found in either the central apical depression of the rhynchus or in the middle of the ventral indentation. Also, spines were rarely seen on the tegument around mouth, around the genital aperture or close to the excretory pore. P. aculeatus has spines of a different shape, as wide as they are long and with a rounded margin. They cover the whole body and almost the entire rhynchus, but none were found in the middle of the rhynchus or on its neck region.
Athyrium pachyphlebium C. is a popular ornamental fern with considerable shade tolerance. The aim of this study was to investigate how the mature sporophytes acclimate to different light levels and to obtain an optimal light environment for their growth both in natural forest canopy and in urban landscapes. Plant growth and morphology, photosynthetic light-response curves and chlorophyll (Chl) fluorescence were measured at four different light levels (45% full sunlight, 30%, 20% and 8%). As the light intensities declined from 45% to 20%, seedling height, crown growth, foliage number and plant lifespan increased significantly. Seedlings grown at 20% light level were vigorous with great ornamental value. Plants grown in deep shade (8% light) showed severe symptoms of lodging and in 45% full sun, the plants showed highlight-stress symptoms. Seedlings in high light levels exhibited a higher
light-saturated photosynthetic rate (P max), light compensation point (LCP), light saturation point (LSP) and a reduced ability for nonphotochemical quenching (NPQ) of excess light than those in low light levels. However, seedlings in low light exhibited greater efficiency in absorbing and utilizing light energy, characterized by higher chlorophyll b (Chl b) and electron transport rate (ETR). These results indicated that a light level of about 20% full sun appeared to be optimal for A. pachyphlebium when both physiological and morphological performance in the landscape were considered. and D. Huang ... [et al.].
The recognition of aquatic organisms plays a crucial role in the monitoring of the pollution and for the adoption of rapid preventive actions. A compact microscopic optical imaging system is proposed in order to acquire and treat the multibands fluorescence of several pigments in phytoplankton organisms. Two algorithms for automatic recognition of phytoplankton were proposed with a minimum number of calibration parameters. The first algorithm provides a morphological recognition based on "watershed" segmentation and Fourier descriptors, while the second one builds fluorescence pigment images by "k-means" partition of intensity ratios. The operation of these algorithms was illustrated by the study of two different organisms: a cyanobacteria (Dolichospermum sp.) and an alga (Cladophora sp.). The family and the genus of these organisms were then classified into a database which is independent of the size, the orientation and the position of the specimens in the images., M. Lauffer, F. Genty, S. Margueron, J. L. Collette., and Obsahuje bibliografii
Morphometric variation of individuals in field collected samples of the Hyalopterus pruni complex from various Prunus species and regions of Greece was examined, to determine whether this variation is correlated with the host-trees from which the aphids originated. Morphometric data for 13 parameters of aphids from 74 field samples (760 adult apterae) were analysed by canonical variates analysis (CVA). Each sample was collected from a different tree and consisted of individuals from 2-3 neighbouring leaves from the same branch. Each field sample was used as a grouping factor in the CVA. The analysis produced three clusters corresponding to the taxa indicated by previous studies using allozyme markers (i.e., Hyalopterus pruni on apricot, blackthorn, plum and cherry, H. amygdali A on almond and H. amygdali B on peach). The separation was independent on the geographical origin of the samples. However, host associations within the complex were not absolute, and in particular the samples from apricot appeared to include both H. pruni and H. amygdali A. In contrast to previous views, the present study showed that the taxa have their own distinct morphology. Lastly, discriminant functions for separating the adult apterae of the taxa are given.
Tomicus piniperda and T. destruens are sibling species which are extremely difficult to separate by morphological characters. Although several papers report differences between the two species, many characters need confirmation or better description. Moreover, new morphological characters are required for correct species determination. For these purposes, eight populations of T. destruens from Italy, Greece, Spain and Algeria, and ten of T. piniperda from Finland, Poland, Czech Republic, Austria, Sweden and Italy, were investigated considering eleven morphological characters. The morphological differences most useful for the species separation include four previously described characters (colour of the elytra, colour of the antennal club, distribution of the antennal setae, distribution of the punctures along the elytral declivity), and four new characters (body proportions, setation of the first antennal club suture, sculpture of the elytral declivity and striae density of the pars stridens). Distribution of the two species is discussed and an illustrated key is included.
In a previous study of a kindling model using stimulation of the entorhinal cortex we found a redistribution of synaptic vesicles into the close vicinity of the active zone of synapses of Type I (Gray 1959) in the hippocampal gyrus dentatus. In this paper, ultrastructural studies of the same model are being continued using planimetry of the synaptic apparatus. A significant increase of the postsynaptic apparatus, area enlargement by 53 %, increase of the perimeter by 28 % and shape irregularity are being reported. No changes in shape or in size have been demonstrated in presynaptic structures or in the morphology of presynaptic mitochondria. These findings are discussed in relation to increased functional readiness of the synapses as signs of active reconstruction of the synaptic apparatus.
Ceratophyllum tanaiticum Sapjegin, a species new to the flora of Hungary, was discovered at two localities in the Hungarian part of the Drava Plain in 2008. These are the westernmost, disjunct localities of this Pontic-Caspian endemic species. For characterization of the Hungarian specimens, nine morphological features of nine Ceratophyllum taxa were used in PCA, CVA analyses and UPGMA classification. In these analyses Hungarian and other C. tanaiticum samples always formed a cluster distinct from other Ceratophyllum taxa. These results confirm an earlier concept in which the character peduncle length contributed the highest loading value for separating C. tanaiticum from other 3–4 leaf-ordered species. Microscopic morphological features, including the number of longitudinally arranged lacunae in one row of parenchymatic tissue between the first and the second dichotomic branching, the length of the sequence between the first and second branching of leaves; number, morphology and width of bracts under the fruit of fresh Hungarian material are identified as new characters for C. tanaiticum, C. submersum and C. demersum.
Brachylecithum microtesticulatum Timon-David, 1955 (Digenea: Dicrocoeliidae) is recorded for the first time in the Black Sea region. The morphology and variability of the digeneans recovered from Larus argentatus in Bulgaria and the Ukraine are described and compared with the redescription of the species (Bartoli and Mas-Coma 1989). Lyperosomum lari Travassos, 1917 of Smogorzhevskaya (1976) is considered a synonym of B. microtesticulatum.
Dimorphism in wing length is well known in many insect species. It is generally believed that a trade-off between dispersal and reproduction exists, with the long-winged (LW) morph being a better disperser due to its superior flight capability. The short-winged (SW) morph is less mobile and it is hypothesised that females of this morph invest more of their energy reserves in producing offspring. We determined the variation in body and wing size in the pygmy grasshopper Tetrix subulata (Orthoptera: Tetrigidae). The results of the morphological study support the occurrence of two clearly distinct wing morphs in both sexes. SW individuals, especially males, were smaller and in accord with proposed developmental instability showed greater variability in body size than LW individuals. Using data for 700 wild-caught individuals from 10 populations, we demonstrate a variable frequency in the percentage of LW individuals, ranging from all-LW to all-SW populations, even if the LW morph is by far the most common morph in an area. The male-biased percentage of LW individuals recorded in intermediate populations supports a difference in the dispersal reproduction trade-off between the sexes., Anja Steenman, Arne W. Lehmann, Gerlind U. Lehmann., and Obsahuje seznam literatury
In November of 2013, a specimen of Japanese sleeper ray, Narke japonica (Temminck et Schlegel), caught off Nanfang-ao, Taiwan was found to be parasitised by the cestode Anteropora japonica (Yamaguti, 1934). Specimens comprised whole worms and free proglottids, both of varying degrees of maturity. This material allowed for the opportunity to examine in detail the developmental progression of this hyperapolytic lecanicephalidean species with regard to overall size, scolex dimensions, and microthrix pattern. Complete immature worms ranged in size from 2.4 mm to 14 mm. The smallest scoleces were half as wide as larger scoleces and exhibited a much smaller ratio of apical organ width to bothridial width. Proglottids more than quadrupled in length during maturation from terminal attached immature to detached proglottids. In addition, a change in microthrix pattern was observed on the anterior region of the proglottids from immature to gravid proglottids; the anterior region of attached immature proglottids is covered with gladiate to coniform spinitriches with capilliform filitriches only rarely visible, whereas this region in detached proglottids is covered with gladiate to coniform spinitriches and conspicuous capilliform filitriches. This is the first report of A. japonica from outside Japan expanding its distribution south to Taiwan. In addition, a preliminary phylogenetic analysis of the genus is presented that suggests congeners from the same host species are not each other's closest relatives, nor is there an apparent phylogenetic signal for apical organ type or reproductive strategy (apolysis). However, reproductive strategy does seem to be correlated with host group such that euapolytic species parasitise dasyatid stingrays while hyperapolytic species parasitise either torpediniform rays or orectolobiform sharks., Rachel R. Guyer and Kirsten Jensen., and Obsahuje bibliografii