Two New Kalyptorhynchia (Turbellaria) from the Coast of Northern New England,USA1

Cystiplana rubra sp.n. and Crassicollum musculare gen. et sp.n. are described and their taxonomy discussed. C. rubra (family Cystiplanidae Karling, 1964) is distinguished by red pigmented stripes, two pairs of cuticular pieces within the copulatory bulb, a small male atrium posterior to the copulatory bulb, and a two part atrial bulb. C. musculare is characterized by a large, unpaired prostatic vesicle with two distinct regions of secretory products, a muscular penis papilla with a small apical stylet, large muscle bolsters bracketing a glandular evagination of the genital atrium, and a large sphincter encircling the genital canal. A new family of Eukalyptorhynchia, Crassicollidae, is erected. Notes on some biological aspects of these species are included.     

Chromosomal evolution in marine triclads and polyclads (Turbellaria)

From an analysis of chromosomal mutations in seven species among five genera of marine triclads and polyclads, three different types of mechanisms of such mutations are identified: 1) rearrangement involving the centromere such that its position is changed, 2) rearrangement of whole chromosome arms, and 3) Robertsonian mechanisms. These mechanisms are the same as those reported for freshwater turbellarians, but aneuploidy and polyploidy, which are common in freshwater species, were not detected in these marine turbellarians.     

Silica spicules and axial filaments of the marine sponge Stelletta grubii (Porifera,Demospongiae)

Summary In all cases an organic axial filament within the silica spicules of Stelletta grubii forms the core of the major axes of the glass. In the small, star-shaped silica spicules (asters) the filament is shown for the first time to be radial with an enlarged center; in the large four-rayed spicules (triaenes) it is four-rayed; and in the large single-rayed spicules (oxeas) the filament is single-rayed. In situ, the filament is not dissolved by boiling nitric acid and thus is apparently protected by encasement within the glass which can also be stratified. The small silica asters are formed by single cells which resemble the so-called spherulous cells of other sponges. The very large size of triaenes and oxeas suggests that they may possibly be formed by more than one cell. The diameter of the filament in the much smaller asters is much narrower than the filament in the larger spicules, indicating a possible relationship between filament diameter and spicule diameter. While the axial filament in larger spicules frequently has a triangular cross-section it can also be hexaognal. Some aster filaments also retain a close to hexagonal cross-section. Filaments freed from large spicules by hydrofluoric acid display a complex morphology; possibly there is an internal silicified core. Some reported aspects of filament morphology are, however, probably artefacts of desilicification with hydrofluoric acid. Offprint requests to: T.L. Simpson, Department of Biology, University of Hartford, West Harford, Connecticut 06117, USA (Permanent affiliation)     

The use of meiofauna in marine pollution impact assessment*

The use of meiofaunal assemblages for the detection and quantification of perturbation of the marine environment by man is examined. The theoretical and practical advantages and drawbacks of meiofaunal monitoring are described and different methods of impact assessment described and evaluated. It is suggested that identification of meiofaunal material need not present a major obstacle to its use, as sensitive responses of meiofaunal assemblages to pollution can be recorded without the necessity for specific identifications. It is concluded that the great sensitivity to pollution of some meiofaunal groups (particularly copepods) offers the potential for better estimation of the real extent of pollution impact than is being achieved by sole reliance on examination of the macrofaunal assemblage. Meiofaunal monitoring should also be considered where there is difficulty in adequate sampling of the macrofauna, due to impoverishment or practical difficulties.     

The role of meiofauna in the marine ecosystem: evolutionary considerations*

The meiobenthos are regarded as the first metazoans to appear on earth This paper considers some aspects of their role in the marine ecosystem over evolutionary time. It is speculatively suggested that they have had a profound influence on many structural and functional attributes of the marine ecosystem as we see it today, both in the benthic and pelagic realms. Certain features such as size spectra, the life-history characteristics of the macrobenthos, and the energetic balance between ecological compartments of the marine ecosystem are considered to result from evolution away from negative interactions with the meiobenthos.     

Ultrastructure of siliceous spicules and microsclerocytes in the marine sponge Neofibularia irata N. SP.

The marine sponge Neofibularia irata contains four different categories of siliceous spicules. These spicules are evident in the tissues as distinct bundles that act to increase the structural rigidity of the sponge. All spicules have a normal structural morphology with silica deposition around a hexagonal axial canal containing a crystalline axial filament. The megasclere strongyles are secreted in typical megasclerocytes. The sigma and raphid microscleres are secreted in individual microsclerocytes that are grouped together in parallel to form loose bundles. However, the microxea microscleres are apparently secreted in distinct tight bundles (trichodragmas) within a single cell. These cells, containing between 13 and 39 spicules, are grouped to form large packets of bundles of spicules.     

Multiple ciliary stuctures in developing spermatozoa of marine Catenulida (Turbellaria)

Summary Numerous short ciliary structures are described in immature spermatozoa of a marine catenulid,Retronectes atypica (Doe and Rieger, 1977). These ciliary structures are associated with spherical bodies consisting of concentric flat vesicles. Since such spherical bodies have been described for several other species of Retronectidae (Sterrer and Rieger, 1974), it is assumed that the multiple ciliary structures may be a characteristic of the whole family. Nuclear morphology and other cytological structures are described for mature and immature stages of spermatogenesis. The finding of these ciliary structures is thought to underline the unique and isolated position of the Catenulida within the Platyhelminthes and the lower worms as a whole.     

New skeletons and new concepts in Amaryllidaceae alkaloids

The Amaryllidaceae alkaloids, represent a group of isoquinoline alkaloids, which are produced almost solely by members of the Amaryllidaceae family. The alkaloids of this family have attracted considerable amount of interest due to some important pharmacological activities they were shown to possess. In the last decade, our phytochemical studies on four Galanthus (Amaryllidaceae) species of Turkish origin have yielded quite a number of new alkaloids with diverse structures. Among these alkaloids, gracilines and plicamines constitute two new subgroups for the Amaryllidaceae alkaloids. The gracilines contain an incorporated 10b,4a-ethanoiminodibenzo[b,d]pyrane skeleton. The plicamines are dinitrogenous compounds, where the oxygen atom in position 7 of a tazettine skeleton is replaced by a nitrogen atom substituted by a pendant 4-hydroxyphenethyl moiety. One of the new alkaloids, galanthindole, which possesses a nonfused indole ring, unlike the already known subgroups of Amaryllidaceae alkaloids, may be considered as the prototype of a third new subgroup of the Amaryllidaceae alkaloids. Additionally, two known isoquinoline alkaloids which do not possess one of the established skeletons of the Amaryllidaceae alkaloids, namely ( − )-capnoidine and (+)-bulbocapnine, have been isolated from a Turkish Galanthus species. Totally, 21 new, 20 known alkaloids and 2 known lignans have been characterized. In this review, the isolation and structure elucidation of these compounds with interesting chemical structures are described.     

A method for the preparation of high-molecular-weight DNA from marine and freshwater triclads (Platyhelminthes, Turbellaria)

Although the last decade has seen much activity devoted to the phylogeny of the Platyhelminthes, such activity has relied in the main on traditional anatomical, ultrastructural, and developmental data. Extension of these studies to the molecular level has been impeded by the lack of a reliable method for the isolation of DNA from these organisms, especially marine triclads whose DNA is particularly difficult to isolate using methods currently used with other eukaryotic or prokaryotic organisms. We report here the details of a method that results in the rapid isolation of relatively pure DNA in good yields from small amounts of material. The method involves the treatment of the animals with high concentrations of NaDodSO4 followed by phenol extraction, resulting in a product that is an excellent substrate for restriction endonuclease digestion and Southern blotting.     

Food-chain relationships in subtidal silty sand marine sediments and the role of meiofauna in stimulating bacterial productivity

Summary From bibliographic data the biomass correlations (organic dry weight) are constructed for the subsurface layer of a hypothetical 30 m deep silty sand station: 200 g/ml macrofauna (including 120 g/ml subsurface deposit feeders), 50 g/ml meiofauna, 20 g/ml Foraminifera, 1 g/ml Ciliata and Flagellata, and 100 g/ml bacteria. ATP-biomass is discussed.Meiofauna and Foraminifera contribute with 30 and 12% to the living biomass in the sediment, and it is assumed that their contribution to the food of deposit-feeding macrofauna is of a similar percentage. This is corroborated by productivity estimations.Bacteria are the main food of deposit feeding macrofauna, meiofauna, and microfauna. From different calculations it becomes evident that the productivity of bacteria in the sediment is far below figures achieved in experimental cultures: the conclusion is that sediment bacteria, in general, do not live under good environmental conditions.A rather large part of the bacterial population in the sediment seems to be in the stationary phase of life, and only a fraction of the total population exhibits high metabolic rates and rapid duplications. Only these active bacteria are of importance for the breakdown of relatively refractive organic matter in the sediment.In soft bottom marine sediments where the input of organic matter is higher than the remineralization rate, benthic animals stimulate by their activities and by nutrient cycling the decomposition of detritus via bacteria. Though meiofauna, in principle, feeds upon the same food resource as macrofauna, there is no real competition for food, because meiofaunal animals by their activities and by excreting metabolic end products induce a bacterial productivity which would not be there without them, and feed on it. There are a few examples where more specialized interactions exist between benthic animals and bacteria; these interactions have been termed gardening. They could be highly important in the benthic ecosystem.     

Distribution of meiofauna in Kongsfjorden,Spitsbergen

Kongsfjorden, a glacial fjord, is a typical fjord in the Spitsbergen (Svalbard archipelago) in the Arctic. The study supports a hypothesis that meiofauna and macrofauna are affected by natural environmental disturbances. Therefore, meiofaunal and macrofaunal analyses can be used to assess the effects of natural environmental disturbances in similar fjords in the Spitsbergen. Inputs from tidal glaciers create steep environmental gradients in sedimentation and salinity along the fjord. The magnitude of the glacial outflow diminishes towards the outer part of the fjord. Glacial-related physical stress causes reduced abundance, biomass and diversity among the meiofaunal assemblages in the inner part of the fjord. Based on quantitative and qualitative analyses of the composition of collected samples, three groups of meiofauna have been distinguished: one outer basin association and two in the inner, glacial bay. The presented results demonstrate that both the meiofauna and the macrofauna are affected on a similar scale by natural environmental disturbances. Therefore, as for macrofauna, meiofaunal analysis can be used to assess the effect of natural environmental disturbances.     

Karyology of a marine population of Gyratrix hermaphroditus (Turbellaria,Rhabdocoela) and chromosomal evolution in this species complex

Karyology and reproductive biology of a marine population of the species complex Gyratrix hermaphroditus, from Roscoff (Brittany, France), have been investigated. A diploid complement of six chromosomes was determined from spermatogonial mitotic figures. One chromosome pair is metacentric, the second is intermediate between meta- and submetacentric, and the third is subtelocentric.In this population, regular meiosis occurs in both female and male germ lines, and the animals reproduce only by means of amphimictic eggs. Certain specimens of the population showed the elimination of one of the three bivalents during the first meiotic division in spermatogenesis. It seems that such animals produce normal and aneuploid sperm simultaneously; the aneuploid sperm are not capable of fertilization.The Roscoff population differs in its karyotype (2n = 6) from freshwater populations, which are either diploid (2n = 4) or polyploid (3n = 6, 4n = 8). These results suggest that aneuploidy played a role in the differentiation of freshwater populations from an originally marine species complex.     

New and Rare Typhloplanoid Species (Turbellaria,Neorhabdocoela) for Fauna of the Urals and Russia

Morphological decriptions and information on the biology and distribution are given for the first time for fauna of the Urals turbellarians from the Neorhabdocoela order of the Typhloplanidae family: Strongylostoma simplex Meixner 1915, Typhloplanella halleziana (Vejdovsky 1880), Phaenocora rufodorsata (Sekera 1904). The species Typhloplanella halleziana was found the first time on the territory of Russia.     

Two New Proschizorhynchus Species from the Coast of Massachusetts, USA (Turbellaria, Kalyptorhynchia)1

Proschizorhynchus nahantensis sp. n. and Proschizorhynchus papillatus sp. n. are described and their taxonomy discussed. P. nahantensis is characterized by its penis papilla which has a proximal spherical and distal tubular portion. A simple stylet is present. The female system is distinguished by the external opening of the vagina and the prominent bursal mouthpiece. P. papillatus is distinguished by the two muscle layers of the copulatory organ, the large straight stylet in the penis papilla, a single gonopore and uterus. Notes on the ecology of the species are included. Views are given on the taxonomy of the genus Proschizorhynchus Meixner, 1928.     

Worldwide occurrence of virus-infections in filamentous marine brown algae

Virus infections were detected inEctocarpus siliculosus andEctocarpus fasciculatus on the coasts of Ireland, California, Peru, southern South America, Australia and New Zealand; in threeFeldmannia species on the coasts of Ireland, continental Chile and Archipelago Juan Fernandez (Chile); and inLeptonematella from Antarctica. Natural populations on the Irish coast contained 3% infected plants inE. fasciculatus, and less than 1% inFeldmannia simplex. On the Californian coast, 15 to 25% ofEctocarpus isolates were infected. Virus symptoms were absent inE. siliculosus from Peru, but appeared after meiosis in laboratory cultures. The virus particles inE. fasciculatus are identical in size and capsid structure to those reported forE. siliculosus, while the virus inF. simplex is smaller and has a different envelope. Our findings suggest that virus infections are a common and worldwide phenomenon in filamentous brown algae.     

Turbellaria in the lagoon of Ghar-el-Melh. Research on the regenerative ability of Monocelis fusca Oersted (Turbellaria, Monocelididae)

The Turbellarian Monocelis fusca Oersted is abundant in the lagoon of Ghar-el-Melh. Traumatic regeneration in this animal is realised for the first time. Transversal sections through two levels of the body are made, and pointed out the presence or the absence of regeneration ability with the considered fragment.