Description of Psammodrilus aedificator sp.n. (Polychaeta), with Notes on the Arctic Interstitial Fauna of Disko Island,W. Greenland*

Psammodrilus aedificator sp.n. is described from an arctic subtidal sandy habitat at 2–3 m depth. The new species represents a link between the two genera Psammodrilus and Psammodriloides, but it has a distinct warty collar shared only with Psammodrilus balanoglossoides. This unique structure was investigated by transmission electron microscopy. Each wart consists of one large cell with microvilli arranged in a hexagonal pattern. The collar epidermis is devoid of cilia. The head consists of prostomium and peristomium, the thorax consists of 7(8) segments, both tagmata totally ciliated. Each of the six pairs of cirri have an aciculum. The abdomen consists of 20 segments and is ciliated except for the dorsal sulcus. Psammodrilus aedifcator sp.n. is sessile and forms a “house” of agglutinated sand grains. Only females (8 mm) and a few juveniles (4 mm) were found in July-August. Mature eggs are extremely large (310 μm), evidently an adaptation to arctic conditions. Throughout the year the interstitial fauna at the type locality was rich, both in species and individuals. Some of the associated fauna included coelenterates, many turbellarians, nemerteans, chaetonotid gastrotrichs, archiannelids and polychaetes and, less abundantly, a few gnathostomulids, macrodasyid gastrotrichs, nematodes, eutardigrades, halacarids, harpacticoid copepods and ostracods.     

Hidden biodiversity in the Arctic – a study of soil seed banks at Disko Island,Qeqertarsuaq, West Greenland

Seed dispersal is a key process in plant community dynamics, and soil seed banks represent seed dispersal in time rather than in space. Despite their potential importance, seed bank dynamics in the Arctic are poorly understood. We investigated soil seed banks and corresponding plant community composition in three contrasting vegetation types in West Greenland, viz. dwarf shrub heaths, herb slopes and fell‐fields. Through germination testing, 31 species were documented in soil seed banks. All of these were herbaceous, while no dwarf‐shrub species, which represents the dominating growth form in the above‐ground vegetation, were emerging from the seed bank. Consequently, across vegetation types, the lowest similarity between seed bank and above‐ground vegetation was found in dwarf shrub heath. Nine plant species were exclusively found in seed bank, all of which were non‐clonal forbs. Seed bank size (total number of seeds) and species richness seemed to increase with the level of natural disturbance. Additionally, we examined the effect of different experimental light and temperature conditions on the quantity and diversity of germinating seeds. The difference in diversity in vegetation and seed bank at the species level will impact population dynamics, regeneration of vegetation after disturbances and its potential to respond to climate change.     

Silica-scaled chrysophytes from West Greenland: Disko Island and the Søndre Strømfjord region

The flora of silica-scaled chrysophytes (Chrysophyceae and Synurophyceae) is known from two previous investigations in southern Greenland, from Narssaq (61°N) and Nuuk (64°N).
In connection with a course in Arctic Biology 25.7.-20.8 1990 chrysophyte samples were obtained from altogether 53 localities, 41 from the Godhavn region in Disko Island (69°N) and 12 from S0ndre Str0mfjord (67°N). The localities were lakes, ponds and puddles, on basalt or an acid bedrock. Fixed samples were examined by EM, and altogether twenty species were identified by their silica scales. Eight of these were new to Greenland, viz. Spiniferomonas silverensis, Mallomonas acaroides, M. alpina, M. crassisquama (previous records proved to belong to M. duerrschmidliae), M. oviformis, M. paludosa, M. tonsurata , and Synura mammillosa. The composition of the flora is discussed from ecological and biogeographic viewpoints.     

Infiltration phyto- and protozooplankton assemblages in the annual sea ice of Disko Island, West Greenland, spring 1996

During the spring of 1996 we occupied a station on annual sea ice located several kilometers from Disko Island, West Greenland in water depths greater than 200 m. The goal of this 3-week field season was to characterize sea-ice communities and the underlying water column prior to, and during, ice break-up. A heavier than usual snow load depressed the sea ice below sea level and the snow-ice interface became flooded. Some of this flooded region subsequently refroze and the whole process repeated itself when additional snow accumulated. The infiltration phytoplankton and protozooplankton assemblages that developed in this region were abundant and diverse. Algal biomass in the infiltration layer was approximately an order of magnitude greater than in the underlying water column but an order of magnitude less than in the well-developed bottom ice community. The infiltration autotrophic assemblage resembled the bottom-ice assemblage while the protozooplankton assemblage was more similar to the water column assemblage. Received: 13 February 1998 / Accepted: 30 May 1998     

Lecane segersi n.sp. (Rotifera, Lecanidae) from Thailand

Lecane segersi n.sp. collected from a swamp in Udornthani province, northeastern part of Thailand, is described and figured. It is closely related to the common, warm-stenotherm Lecane papuana (Murray), but distinguished by the presence of inwardly directed antero-lateral spines.     

Temperature requirements for growth and survival of macroalgae from Disko Island (Greenland)

The temperature requirements for growth and upper temperature tolerance were determined in 16 macroalgal species collected on Disko Island (Greenland). The upper survival temperatures were examined in 1°C steps, and growth measured at 5°C intervals between 0 and 20°C using a refined method, where the fresh weight was determined weekly or fortnightly over a period of 5 or 6 weeks. To express temperature-growth responses, growth rates of temperature-acclimated plants were taken. Two groups with different temperature requirements were identified: (1) A stenothermal group includingAcrosiphonia arcta, Acrosiphonia sonderi, Urospora penicilliformis, Devaleraea ramentacea, Desmarestia aculeata, Pilayella littoralis, growing between 0 and (10 to) 15 (or 20)°C with optima between 0 and 10°C. The upper survival temperatures in these species and inChromastrum secundatum, Chromastrum virgatulum, Chordaria flagelliformis were between 17 and 23°C (duration of experiment: 2 weeks). (2) A eurythermal group includingEnteromorpha clathrata, Enteromorpha intestinalis andPolysiphonia urceolata growing between 0 and 20°C with growth optima at 10 or 15°C. The upper survival temperatures in these species and inChaetomorpha tortuosa, Bangia atropurpurea andEudesme virescens were between 24 and 31°C. These algal species showed little adaptation to the Arctic temperatures. In contrast, algae from the first group exhibited a relatively high adaptation to low temperatures — approaching the low temperature requirements of Antarctic algae. The results are discussed in relation to the geographic distribution of individual species.     

Hematozoa from Southern African vultures, with a description of Haemoproteus janovyi sp. n.

This study represents the first major survey of avian hematozoa from southern Africa and the only one dealing with blood parasites of vultures. Blood smears from 506 Rhodesian, Botswanan and South African vultures (Hooded, White-headed, Lappetfaced, Cape Griffon and Whitebacked Vultures) were examined for hematozoa. Haemoproteus janovyi sp. n. was observed in 35.2% of the vultures, Leucocytozoon toddi in 0.8%, Plasmodium fallax in 0.6%, Atoxoplasma sp. in 1.4% and microfilariae in 0.2%. Hematozoan prevalence increased with age of the vultures. Only 2 of 133 nestlings sampled during the dry season had patent parasitemias (L. toddi). Haemoproteid prevalence in immature vultures was depressed during the dry season, whereas it was stable throughout the year in adults. The only species which nests on cliffs (the Cape Griffon Vulture) did not harbor hematozoa whereas the other species which nest and roost in trees were infected with at least one hematozoan species.     

Papposphaera iugifera nov. sp. from West Greenland,Svalbard, and the Baltic Sea

We are currently revisiting coccolithophore genera and species described from high latitudes in both hemispheres, and also in the process describing new taxa when appropriate, with the aim of providing the best possible framework for polar species segregation based on external morphological features only. The present paper thus introduces Papposphaera iugifera nov. sp. from West Greenland (Disko – type locality), Svalbard (Isfjorden) and the Baltic Sea (Bothnian Sea). P. iugifera is clearly related to P. sagittifera, P. sarion and P. arctica and forms with these a continuum of species that are, with the exception of P. sarion, on the one hand much similar with respect to calicate spine details, while on the other hand clearly differentiated with respect to the complexity of central area calcification. While this is extensive in P. sagittifera it is reduced to just a single transverse bar or even completely absent in P. iugifera.     

On the taxonomy of three sympatric sibling species of the Brachionus plicatilis (Rotifera) complex from Spain, with the description of B. ibericus n. sp.

The accumulation of evidence during the last decade led to thesplitting of the Brachionus plicatilis complex (Rotifera) intotwo morphologically recognizable species: B. plicatilis Müllerand B. rotundiformis Tschugunoff, previously referred to asL- and S-type B. plicatilis (s.l.), respectively. However, recentpopulation genetics and molecular studies have revealed thateach of these taxa concern cryptic species complexes. In particular,in Torreblanca Marsh, a wetland on the Mediterranean coast ofSpain, three genetically distinct groups in this rotifer complexhave been shown to co-occur. Differences in genetic markers,ecological preferences, mixis responses, mating behaviour andno evidence of gene flow between them have led to the conclusionthat they must be considered as three different biological species.In this study we present a detailed comparative analysis usinglight and scanning electron microscopy of laboratory strainsenabling a morphological characterization of the three species.Fine morphology and morphometry revealed taxonomic charactersconstant enough to recognize three well-defined morphologies,which always correspond with the respective biological speciesidentified. Since no type material of both B. plicatilis andB. rotundiformis is available, we designed our Spanish clonesas neotypes, which would allow further comparative work. Furthermore,B. ibericus n. sp. is described. This study sets the first stepfor a complete characterization of the biological diversitycontained within this economically important species complex.     

Opheliidae (Polychaeta) from the Southwestern Atlantic ocean, with the description of Travisia amadoi n. sp., Ophelina gaucha n. sp. and Ophelina alata n. sp.

The diet of the brackish water tilapia Sarotherodon melanotheron is studied in various riverine and lacustrine systems of the Bia River basin (Côte d'Ivoire). Comparison of the diet between sampling sites (upper course, lower course and man-made Lake Ayame) shows significant differences. In the man-made lake, prey described as preferential include Asterionella (Bacillariophyceae) and Bosmina(Cladocera). In the lower course, the preferential preys are represented by Lyngbya(Cyanophyceae) while in the upper course Lyngbya and chironomid larvae are preferential. These differences are related to the altered environmental conditions generated by the construction of the dam on the Bia river main stream. In the man-made lake, there is no shift in diet either with the seasons (dry and rainy seasons) or with size.     

Testicular myxosporidiasis in anurans,with a description of Myxobolus fallax n. sp.

During studies of amphibian sperm cryopreservation, a new species of myxosporidean parasite (Myxozoa, Myxosporae) was observed in the testes of the Australian dwarf green tree frog Litoria fallax (Peters). Myxosporidiasis was found to have no affect on L. fallax body condition or sperm numbers. Myxobolus spores from L. fallax are morphologically distinct from Myxobolus hylae spores (infecting the sympatric Litoria aurea Lesson) and the three previously named (exotic to Australia) Myxobolus species found in anurans. Myxobolus fallax n. sp. is characterised by: pseudocyst white, spherical to ovoid, 141 x 74 to 438 x 337 microm in diameter (mature); plasmodium with spores loosely arranged within interior. Spores ovoid 13.4 +/- 0.5 (12.6-14.6) microm length, 9.5 +/- 0.4 (8.3-10.6) microm width, 6.8 +/- 0.4 (6.5-7.6) microm depth, 1.4 +/- 0.1 (1.3-1.6) length/width; polar capsules broadly pyriform and equal in size 4.2 +/- 0.3 (3.3-4.7) microm length, 2.4 +/- 0.2 (2.1-2.8) microm width; filament coils 7-8, wound tightly and perpendicular to the longitudinal axis of the capsule; polar filament 34 +/- 7.0 (18-50) microm length; intercapsular appendix and sutural ridge folds absent; and iodinophilous vacuole and mucous envelope lacking. In addition to this new species, data from archival samples of M. hylae are provided which show two morphologically distinct spore types. Both appeared rarely in the same pseudocysts and we cautiously retain the single species.     

Clostridium oceanicum, sp. n., a Sporeforming Anaerobe Isolated from Marine Sediments

Fourteen strains of a terminal-spored anaerobe were isolated from marine sediments obtained off the Atlantic and Pacific coasts of tropical South America. These strains are proteolytic, lecithinolytic, only slightly saccharolytic, often form cells with two spores, and appear unlike any described species of terminal-spored, proteolytic anaerobe. The name Clostridium oceanicum is suggested. The type strain (no. 25647) is deposited in the American Type Culture Collection.     

Food habits of fishes on an exposed sandy beach at Fukiagehama,South-West Kyushu Island,Japan

To clarify the feeding habits and major food sources of sandy beach fishes, the gut contents of 55 fish species collected on a sandy beach at Fukiagehama, South-West Kyushu Island, Japan, were examined. Ontogenetic changes in food preference were recognized in nine species (Hypoatherina valenciennei, Lateolabrax japonicus, Trachurus japonicus, Sillago japonica, Sphyraena japonica, Paralichthys olivaceus, Heteromycteris japonica, Paraplagusia japonica, and Takifugu niphobles). A cluster analysis based on dietary overlaps showed that the sandy beach fish assemblage comprised six trophic groups (mysid, amphipod, zooplankton, juvenile fish, terrestrial insect, and mollusk feeders). Of these, the first three groups were the most abundantly represented, whereas the last two were represented by only a single species. These results indicated that epibenthic macrofauna, such as mysids and gammaridean amphipods, and zooplankton, were important food resources for the fish assemblage at the study site, but infaunal macrobenthos, such as polychaetes and bivalves, being relatively unimportant.     

Mallomonas nuussuaqensis nov. sp., a new species of silica-scaled chrysophytes from West Greenland

A new species of Mallomonas, M. nuussuaqensis was found to be common in samples collected from waterbodies on Nuussuaq/Nûgssuaq (70N-71N, West Greenland). The species has very compact silica scales with a thick broad marginal rim and a very thick and broad hood, which often occupies more than two thirds of the shield.