Aeciospore surface structures ofGymnosporangium andRoestelia (Uredinales)

Aeciospore surface structures of 40Gymnosporangium species and 7Roestelia species were investigated with a scanning electron microscope. The surface structures of aeciospores were classified into 12 types on the basis of shape and size of processes. Surface structures of the aeciospores were stable within each species. Therefore, it is suggested that surface structures of aeciospores could be used as an important diagnostic criteria in identifyingGymnosporangium andRoestelia species. Contribution No 139, Laboratory of Plant Pathology and Mycology, Institute of Agriculture and Forestry, University of Tsukuba.     

High abundance of Trochospongilla horrida (Porifera, Spongillidae) in the Rhine (Germany) 1992–1995

Trochospongilla horrida (Porifera, Spongillidae) was the dominant freshwater sponge in the Rhine between Karlsruhe and Bonn between 1992 and 1995 are reported. It showed an annual life cycle, with an inactive phase during winter. The life cycle was controlled by temperature. Gemmules were produced in high numbers, and played a significant role as resting bodies. Their role as distribution units was negligible because they were tightly fixed to the substratum. Trochospongilla horrida preferred relatively stable habitats, not affected by fluctuations in water level; it was restricted to habitats with a slightly alkaline pH. Laboratory experiments showed a delayed germination of the gemmules, which explains why the highest abundance of the species occured considerably after the first hatching colonies.     

The naupliar stages of Cyclopina yutimaete Lotufo (Cyclopinidae,Cyclopoida)

The six naupliar stages of Cyclopina yutimaete Lotufo are described and compared to other cyclopoid nauplii. They seem more similar to freshwater cyclopoid nauplii than to marine species. The hirsute aspect of the last segment of the antennule is of diagnostic value for these nauplii.     

Surface structures of peridial cells ofGymnosporangium andRoestelia (Uredinales)

The surface structures of peridial cell walls (outer, side, and inner walls) of 40Gymnosporangium and 7Roestelia species were examined by scanning electron microscopy. These surface structures were classified into 10 types based on shape, size, and density of the processes. Surface structural types of each wall were stable within a species. Therefore, it is suggested that surface structure types of peridial cell walls could be used as important diagnostic characteristics ofGymnosporangium andRoestelia species. Contribution No. 140, Laboratory of Plant Pathology and Mycology, Institute of Agriculture and Forestry, University of Tsukuba.     

<Emphasis Type="Italic">Rhinoglena kutikovae</Emphasis> n.sp. (Rotifera: Monogononta: Epiphanidae) from the Bunger Hills,East Antarctica: a probable relict species that survived Quaternary glaciations on the continent

A new species of rotifer, Rhinoglena kutikovae n.sp. (Monogononta: Epiphanidae), is described from a freshwater lake in the Bunger Hills, East Antarctica. The new taxon is characterized by the following combination of characters: body conical to vase-shaped; a single toe; distal foot pseudosegment bulged; tail prominent, semi-circular; two small spherical pedal glands with common duct, forming a complex with caudal ganglion; trophi with seven major teeth with offset head and two smaller teeth without offset head. The new species is compared with R. fertoeensis, R. frontalis and R. tokioensis, of which scanning electron microscopic information is presented of the trophi. R. kutikovae n.sp. is probably a relict species that survived Quaternary glaciations in glacial lacustrine refugia on the Antarctic continent.     

Scanning electron microscope study of epidermal surface of six ectosymbiotic Temnocephala species (Platyhelminthes) from Argentina

The epidermis of six ectosymbiontic Temnocephala species (T. axenos, T. chilensis, T. digitata, T. microdactyla and T. pignalberiae from freshwater crustaceans and T. iheringi from a mollusc) from Argentina examined using scanning electron microscopy revealed characters indicating their relationships with other members of the Platyhelminthes and with the congeneric Australian and New Zealand species. In all species, the whole surface is covered with microvilli and no locomotory cilia were observed. Aggregates of monociliated receptors are on the tentacles of all species and on the ventral surfaces of three. Furthermore, T. axenos and T. chilensis show other ciliated structures interpreted as collar receptors, such as those described for some turbellarian groups (e.g. Proseriata and Rhabdocoela). Two species (T. digitata and T. iheringi) show structures that are probably related to the duo-gland adhesive system.     

The effects of cadmium and mercury on gemmule formation and gemmosclere morphology in Ephydatia fluviatilis (Porifera : Spongillidae)

A laboratory study of the effects of cadmium and mercury on the freshwater sponge, Ephydatia fluviatilis, was conducted. Sponge cuttings were exposed to concentrations of cadmium or mercury which ranged from 1.000 to 0.001 ppm for one month. The responses exhibited by the specimens resulted in four groups characterized as follows: sponge colony survived and produced gemmules with normal gemmoscleres; sponge colony survived and produced gemmules with malformed gemmoscleres; sponge colony survived but did not gemmulate; sponge colony died. A direct discriminant functions analysis of the four sponge groups, metal concentrations and other chemical data established a highly significant correlation between increasing metal concentrations and amount of damage to the sponge.     

Effects of calcium and salinity on the growth rate of Ephydatia fluviatilis (Porifera: Spongillidae)

The freshwater sponge, Ephydatia fluviatilis (Porifera: Spongillidae), was maintained in a continuous-flow laboratory culture system under several conditions of calcium ion (Ca⁺⁺) concentration and salinity. Experimental results suggest that sponge growth rate increases with increasing Ca⁺⁺ concentration, that sponge growth rate decreases with increasing salinity, and that the negative effect of higher salinity can be overcome by increasing Ca⁺⁺ concentration. The experimental results correlate well with field observations on the effects of salinity and Ca⁺⁺ on the distribution of E. fluviatilis.     

<Emphasis Type="Italic">Prorocentrum rivalis</Emphasis> sp. nov. (Dinophyceae) and its phylogenetic affinities inferred from analysis of a mixed morphological and LSU rRNA data set

A new freshwater epiphytic Prorocentrum species, Prorocentrum rivalis, from the temperate region of the Haute-Vienne, France, is described. This species is the third freshwater species identified among approximately 60 marine Prorocentrum species. This new species is described using scanning electron microscope and phylogenetic analyses by a polyphasic approach (LSU rRNA sequences combined with 9 morphological characters). The phylogenetic analysis attests that P. rivalis is close to other planktonic freshwater species and the freshwater Prorocentrum clade is evolutionarily derived from an epiphytic freshwater prorocentroid ancestor. The unique marine species in the freshwater clade results from an ecophysiological reversion. P. rivalis differs from other epiphytic taxa by its rarity, its temperate distribution and its ecophysiological needs. The phylogeny confirms also that all planktonic Prorocentrum species are evolutionarily derived from epiphytic/benthic ancestors.     

The taxonomic and ecological status of the environmentally restricted spongillid species of North America. IV. Spongilla heterosclerifera Smith 1918

The taxonomic status, present distribution and specific threats to the existence of the environmentally restricted freshwater sponge, Spongilla heterosclerifera Smith 1918 were investigated. This species, collected only from Oneida Lake, New York, has not colonized other habitats and continues to exhibit typical diagnostic characteristics, thus qualifying as a valid environmentally restricted species. Although the sponge presently colonizes two sites in the lake, both near the northwestern shore, the total absence of sponge fauna from other lake regions near more heavily populated areas of this species. Physicochemical data from Oneida Lake greatly extend the known environmental parameters of Spongilla heterosclerifera.     

Epibiontic and endobiontic polychaetes of Geodia cydonium (Porifera,Demospongiae) from the Mediterranean Sea

Polychaete assemblages associated to the sponge Geodia cydonium were investigated at two sampling sites in the Mediterranean Sea: Porto Cesareo Basin (Apulia) and Marsala Lagoon (Sicily), both characterized by sheltered hydrodynamic conditions. Samples were seasonally performed during 1997, in order to compare the assemblages coming from the two localities studied, considering separately the internal and external tissues of the sponge, and with the aim of evaluating the influence of sponge size on polychaete colonization. The examined sponge is characterized by a peculiar stratification of its tissues: an external thick and hard layer, the cortex, and an internal softer one, the choanosome. Statistical analysis showed that this was the main factor controlling polychaete assemblage, with the internal tissue, less rich and diversified, appearing impoverished with respect to the external layer. A similarity in species composition was observed between sites, even though some differences were evidenced in the abundance of some species, mainly reflecting differences in local environmental conditions. Species richness and density increased with the increasing sponge size. Such a situation is particularly evident at Porto Cesareo, where sponges are covered by an algal layer which is particularly rich on the largest specimens, thus suggesting that most of the species of polychaetes were linked more to the neighbouring environment than to the sponge itself.     

Survey of leaf anatomy,especially secretory structures,of tribeCaesalpinieae (Leguminosae,Caesalpinioideae)

We studied leaflet anatomy, emphasizing secretory structures, from herbarium specimens of 128 species of 44 genera of tribeCaesalpinieae, using clearings, resin sections, and scanning electron microscopy. These observations, combined with those from our three earlier papers, provide a survey of 210 species representing all genera. Seventy-three species had secretory structures: 21 had glands or gland-like trichomes, 40 had living mesophyll idioblasts, and nine had cavities (three species each had two different types). Five additional species, all inCercidium (Caesalpinia group), had paired or clustered large spheroidal, thick-walled, empty cells (veinlet idioblasts) interconnected by perforation plate-like gaps. Secretory structures have systematic significance at various taxonomic levels.     

Morphological differences and molecular phylogeny of freshwater blooming species, Peridiniopsis spp. (Dinophyceae) from China

In 2008–2010, several freshwater dinoflagellate blooms caused by Peridiniopsis spp. were observed in China. P. penardii and P. niei sampled from various geographical localities were examined by means of light and scanning electron microscopy. After comparing morphological and molecular differences, the new freshwater variety Peridiniopsis penardii var. robusta var. nov. (Peridiniales, Dinophyceae) found in Manwan Reservoir, Yunnan Province was described. The new variety differed from P. penardii since it possessed numerous robust antapical spines and a conspicuous apical spine. Molecular phylogenetic analyses based on SSU, LSU and ITS indicated P. niei, P. penardii and P. penardii var. robusta were closely related with P. kevei, and clustered into a monophyletic clade. The new variety possessed an endosymbiotic diatom which was similar to P. penardii and P. kevei, whereas the endosymbiont was not present in cells of P. niei. The endosymbiont SSU and ITS phylogenies showed that the endosymbionts of these three dinoflagellates were closely related to members of Thalassiosirales. Furthermore it was concluded that the endosymbionts might originate from Discostella-like species.     

Cytochemical investigations of the alveolar plates of theEuplotidae (Ciliophora,Hypotrichida)

Summary The ultrastructural appearance of organic plates lying in the alveoli of a freshwater species ofEuplotes is described and seen to be similar to those previously reported from the marine speciesE. vannus. Enzymatic digestion using pepsin and trypsin indicates that the plates in both species are mainly composed of protein with a fine coating of polysaccharides, as revealed using the Thiéry-technique for polysaccharide staining.     

Pollen of Ceratostema (Ericaceae, Vaccinieae): tetrads without septa

The pollen morphology of two species of the Neotropical genus Ceratostema (Ericaceae) was examined by light, scanning and transmission electron microscopy. The Ceratostema species examined have 3-colporate pollen grains united in permanent tetrahedral tetrads that show a common condition encountered in the Ericaceae. But the septal exine was absent between two neighboring grains in each pollen tetrad of Ceratostema. The pollen tetrads without septa are the first report for the Ericaceae as well as other angiosperm families.     

Phylogenetic analysis of Spiroplasmas from three freshwater crustaceans (Eriocheir sinensis, Procambarus clarkia and Penaeus vannamei) in China

Disease epizootics in freshwater culture crustaceans (crab, crayfish and shrimp) gained high attention recently in China, due to intensive developments of freshwater aquacultures. Spiroplasma was identified as a lethal pathogen of the above three freshwater crustaceans in previous studies. Further characterization of these freshwater crustacean Spiroplasma strains were analyzed in the current study. Phylogenetic position was investigated by analysis of partial nucleotide sequences of 16S ribosomal RNA (rRNA), gyrB and rpoB genes, together with complete sequencing of 23S rRNA gene and 16S–23S rRNA intergenetic spacer regions (ISRs). Phylogenetic analysis of these sequences showed that the above-mentioned three freshwater crustacean Spiroplasma strains were identical and had a close relationship with Spiroplasma mirum. Furthermore, the genomic size, serological studies and experimental infection characteristics confirmed that three freshwater crustacean Spiroplasma strains are a single species other than traditional S. mirum. Therefore, these data suggest that a single species of Spiroplasma infects all three investigated freshwater crustaceans in China, and is a potential candidate for a new species within the Spiroplasma genus. These results provide critical information for the further investigations in fresh aquaculture epizootics related to tremor diseases, caused by this infectious agent.