On the affinities ofZuluscaphites van Hoepen 1955 (Cretaceous Ammonoidea) from the Albian of Zululand,South Africa

Zuluscaphites van Hoepen 1955, an enigmatic ammonite originally described from the Middle or Upper Albian of Zululand, South Africa, is shown to be a member of the acanthoceratacean family Lyelliceratidae, subfamily Stoliczkaiinae; it is not a heteromorph as originally proposed. Huescarites Latil 1991 is a junior synonym of Zuluscaphites as are the type species of the two genera, Z. orycteropusi and H. companyi.     

Fossil amoebae (Hemiarcherellidae fam. nov.) from Albian (Cretaceous) amber of France

Abstract: Two extraordinarily well‐preserved testate amoebae are described from Late Albian age amber from south‐western France. The specimens are attributed to a new family, the Hemiarcherellidae fam. nov., and are described as Hemiarcherella christellae gen. et sp. nov. The amoebae described herein originate from highly fossiliferous amber pieces. Based on syninclusions, Hemiarcherella christellae was a soil‐dwelling organism, probably an active bacterivore. This taxon represents the third species of testate amoebae described from mid‐Cretaceous French amber. Analysis of this fossil amoeba fauna illustrates the uniqueness of mid‐Cretaceous French amber deposits. Indeed, most amoebae found in amber have been assigned to modern species, corroborating the hypothesis of morphological stasis in different microbial lineages. However, the well‐preserved amoebae fauna found in French amber can be distinguished clearly from modern species and help us to better understand the fossil record of these organisms.     

New records of ahermatypic scleractinian corals from the Kuril Islands

Four species of caryophyllid scleractinians, Caryophylla ambrosia, C. scobinosa, C. alaskensis, and Polymyces montereyensis, were recorded for the first time in the Sea of Okhotsk off the Kuril Islands. These findings extend the range for the species, of which three had previously been considered to be restricted to the tropical and warm Indopacific waters. These data will supplement regional reports on the bottom fauna of the most fertile and extensively commercially exploited continental shelf region of the North Pacific.Original Russian Text Copyright © 2004 by Biologiya Morya, Latypov.     

Regulation of release of antibacterials from stressed scleractinian corals

Recently, we showed that mechanical stress on scleractinian (stony) corals caused a rapid release of antibacterial material (referred to as coral antibacterial activity, or CAA), which killed various bacterial species, including the coral pathogen Vibrio coralliilyticus . We now report on studies on the regulation of CAA release from stressed scleractinian corals. Corals can repeatedly release highly active CAA as a result of sequential stress inductions. Coral fragments were transferred 19 times from one beaker into another with a stress induction each time after 10 min. There was a decrease in the level of antibacterial activity released during the first four to five transfers. After the fifth transfer, the corals kept releasing CAA for the rest of the experiment with no significant decrease. Apparently, the release of CAA is downregulated by feedback inhibition, depending on the concentration of CAA in the surrounding water. By separating CAA-treated V. coralliilyticus from the surrounding water, it was shown that CAA was bound irreversibly to bacterial cells in a stoichiometric manner. Approximately 4 × 10² bacterial cells were sufficient to bind 1 U of CAA. Resident coral bacteria were more resistant to CAA than bacteria isolated from seawater, suggesting an ecological role for CAA. CAA release was obtained from corals after removal of the mucus layer, and the mucus itself contained antibacterial activity.     

Nucleotide sequences of highly repetitive DNA from scleractinian corals

The staghorn coral genome contains 5% of a satellite DNA, consisting of 80 to 300 x 10(3) copies of a 118-bp repeat unit per haploid Acropora genome.     

17Beta-hydroxysteroid dehydrogenase (17beta-HSD) in scleractinian corals and zooxanthellae

Steroid metabolism studies have yielded evidence of 17β-hydroxysteroid dehydrogenase (17β-HSD) activity in corals. This project was undertaken to clarify whether there are multiple isoforms of 17β-HSD, whether activity levels vary seasonally, and if zooxanthellae contribute to activity. 17β-HSD activity was characterized in zooxanthellate and azooxanthellate coral fragments collected in summer and winter and in zooxanthellae cultured from Montipora capitata. More specifically, 17β-HSD activity was characterized with regard to steroid substrate and inhibitor specificity, coenzyme specificity, and Michaelis constants for estradiol (E₂) and NADP⁺. Six samples each of M. capitata and Tubastrea coccinea (three summers, three winters) were assayed with E₂ and NADP⁺. Specific activity levels (pmol/mg protein) varied 10-fold among M. capitata samples and 6-fold among T. coccinea samples. There was overlap of activity levels between summer and winter samples. NADP⁺ / NAD⁺ activity ratios varied from 1.6 to 22.2 for M. capatita, 2.3 to 3.8 for T. coccinea and 0.7 to 1.1 for zooxanthellae. Coumestrol was the most inhibitory of the steroids and phytoestrogens tested. Our data confirm that corals and zooxanthellae contain 17β-HSD and are consistent with the presence of more than one isoform of the enzyme.     

Carbohydrate composition of mucus from scleractinian corals from the central Red Sea

Coral Reefs - Coral mucus is continuously released by most corals and acts as an important protective barrier and as a substrate for host-associated microbial communities due to its complex...     

Reproductive structures of an extinct platanoid from the early Cretaceous (latest Albian) of eastern North America

Two new species of platanoid reproductive structure are described from the Bull Mountain locality in the Patapsco Formation (Potomac Group) of northeastern Maryland, USA. Pistillate inflorescences and infructescences (Platanocarpus elkneckensis sp. nov.) consist of flowers and fruits in sessile globose heads that are borne on an elongate axis. Individual pistillate flowers consist of five free carpels surrounded by prominent tepals. Staminate inflorescences, flowers and isolated stamens are assigned to Hamatia elkneckensis gen. et sp. nov. Staminate flowers are borne in a globose head with a small number of stamens (five?) per flower. Stamens consist of very short filaments, long anthers with strongly valvate dehiscence and an apically expanded connective. The connective expansion is frequently very well-developed, hook-like and extends down the ventral surface of the stamen. Anthers contain small, tricolporate, reticulate pollen. Association evidence, similarity of inflorescence structure and the occurrence of Hamatia-type pollen on flowers, carpels and fruits of Platanocarpus elkneckensis suggests that the staminate and pistillate material was produced by a single species of plant. The “Hamatia-plant” provides further evidence of pentamerous floral structure in mid-Cretaceous platanoids and documents the occurrence of unequivocal tricolporate pollen in the platanoid complex.     

Molecular diversity of symbiotic algae (zooxanthellae) in scleractinian corals of Kenya

In this first sequence analysis of ‘zooxanthellae’ (symbiotic algae of the genus Symbiodinium) in scleractinian corals in Africa, seven Kenyan species sampled in 2001–2002 were analysed by RFLP and sequencing of a PCR-amplified fragment of the LSU rRNA gene. Zooxanthellae of phylotypes A, C and D, all described previously in corals from other regions of the world, were detected. All sequences of phylotype D were identical, while phylotype C was variable, with 14 distinct sequences, seven of which clustered in a previously unreported subgroup of phylotype C, among the 22 samples. These data on the diversity of zooxanthellae in Kenyan corals 3–4 years after the 1998 bleaching event are of potential value for longitudinal studies of temporal changes in zooxanthella diversity in Kenyan corals, especially in relation to future large-scale bleaching episodes.     

Marsileaceaephyllum, a new genus for marsileaceous macrofossils: leaf remains from the Early Cretaceous (Albian) of southern Gondwana

Three new taxa from Albian, Early Cretaceous assemblages in Gondwana (Australia and Antarctica) and two previously described fossils from the Late Cretaceous and Eocene of North America are attributable to the heterosporous semi-aquatic fern family Marsileaceae. They are assigned to Marsileaceaephyllum, a morphotaxon erected here for sterile remains (whole plants, and isolated leaves and leaflets) of Marsileaceae. The Gondwanan taxa, Marsileaceaephyllum lobatum and Marsileaceaephyllum spp. B-C, have either a cruciform leaflet arrangement or dichotomous and anastomosing venation characteristic of modern Marsileaceae. Two previously established taxa, Marsilea johnhallii and Marsilea sp., which represent sterile Marsileaceae, are also transferred to the new genus (now Marsileaceaephyllum johnhallii and Marsileaceaephyllum sp. A, respectively). Examination of all fossil venation patterns reveals four new venation types not present in extant taxa, suggesting that most fossil Marsileaceae (leaves) are distinct from extant genera, and are likely members of extinct lineages. This is further supported by the absence of modern megaspore types in the Early Cretaceous.     

Mid-Cretaceous/Albian (Cretaceous) ostracod assemblages from NW Hungary reflecting deep marine,nearshore and non-marine environments

The Albian sediments of the Transdanubian Range in Hungary were deposited in non-marine to fully-marine environments. The studied sections revealed diverse benthic ostracod faunas with moderately-preserved specimens. Forty-six taxa are identified and Cypridea zalanyii n. sp. is newly described. The detailed palaeoecological study of these ostracod faunas provided an opportunity to distinguish eight assemblages. The assemblages include limnic, brackish lagoon, shallow marine, reef and low oxygenated semi-enclosed basin environments in the Northern Tethys region we investigated. This work contributes to the knowledge about Albian non-marine faunas from Europe and explores ecological requirements of brackish faunas.     

First record ofBorelis melo andDendritina sp. in the Messinian of SE Spain (Cabo de Gata, Province Almeria)

Borelis melo andDendritina sp. occur in Messinian carbonates of the Cabo de Gata near Almeria. This is the first record of these larger benthic foraminifera from Messinian deposits in SE Spain. Two foraminiferal assemblages are differentiated: firstly, aBorelis- Dendritina assemblage which occurs on reef flanks, and secondly a lagoonal monospecificDendritina fauna.     

Low genetic diversity of symbiotic dinoflagellates (Symbiodinium) in scleractinian corals from tropical reefs in southern Hainan Island, China

Endosymbiotic dinoflagellates in the genus Symbiodinium are among the most abundant and important group of photosynthetic protists found in coral reef ecosystems.In order to further characterize this diversity and compare with other regions of the Pacific,samples from 44 species of scleractinian corals representing 20 genera and 9 families,were collected from tropical reefs in southern Hainan Island,China.Denaturing gradient gel electrophoresis fingerprinting of the ribosomal internal transcribed spacer 2 identified 11 genetically distinct Symbiodinium types that have been reported previously.The majority of reef-building coral species (88.6％) harbored only one subcladal type of symbiont,dominated by host-generalist C1 and C3,and was influenced little by the host’s apparent mode of symbiont acquisition.Some species harbored more than one clade of Symbiodinium (clades C,D) concurrently.Although geographically isolated from the rest of the Pacific,the symbiont diversity in southern Hainan Island was relatively low and similar to both the Great Barrier Reef and Hawaii symbiont assemblages (dominated by clade C Symbiodinium).These results indicate that a specialist symbiont is not a prerequisite for existence in remote and isolated areas,but additional work in other geographic regions is necessary to test this idea.     

Free-living scleractinian corals on reefs of the Seychelles Islands

Thirty-nine species of unattached scleractinian corals that belong to 22 genera of 9 families were found on the Seychelles reefs. Variations of the colony form of corals living on soft sediments under continuous wave action are described. Irrespective of their initial growth form and taxonomic position, corals assume a form close to spherical. Because of the worldwide deterioration of coral reefs, the adaptation to changing ecological conditions by reef-building corals needs to be studied.     

Spermatozoan ultrastructure of scleractinian corals from the eastern Pacific: Pocilloporidae and Agariciidae

Spermatozoa ofPocillopora damicornis, Pocillopora elegans (Astrocoeniina, Pocilloporidae) andPavona gigantea (Fungiina, Agariciidae) from the eastern Pacific (Isla del Caño, Costa Rica) were examined using transmission electron microscopy. The hermaphroditic pocilloporidsP. damicornis andP. elegans are spermiomorphologically very similar to hermaphroditic acroporids, being characterized by bullet-shaped nuclei and elongated mitochondria. Such traits have not been found in other families. Thus, the suborder Astrocoeniina, including pocilloporids and acroporids, can clearly be distinguished from other scleractinian suborders. This separation underlines the isolated position of the Astrocoeniina within the order Scleractinia following the evolutionary scheme of Wells. A conical sperm type, known from gonochoric species (sexes separate) from all families except Acroporidae and Pocilloporidae, was found in the gonochoric agariciidPavona gigantea. This supports previous findings that gonochoric corals share a unique and common sperm structure regardless of which family they belong to. However, no gonochoric Astrocoeniina have ever been examined. Hence, the question whether the sperm type common to gonochorists is also represented in Astrocoeniina, which would undermine the ultrastructural distinction of Astrocoeniina and other suborders seen among hermaphrodites, as well as the systematic value of sperm structure within scleractinian corals, remains open.     

Sur quelques zooplanctontes abondants dans l'upwelling de Cabo Frio (Bresil)

On some zooplankters common in the Cabo Frio (Brazil) upwelling.In the waters off Cabo Frio zooplankton maxima are observedbetween February and April, which is the period of upwellingoccurrence. Copepods are highly diversified; we identified 96species at a single collecting station during one year. In summerCalanoides carinatus, Paracalanus parvus and Oncea media areabundant, whereas we observed dominance of Temora stylifera,Clausocalanus furcatus, C. arcuicomis, Oithona plumifera andgreat quantity of Creseis acicula during winter. Chaetognatha(Sagitta enflata), Appendicularia (Oikopleura longicauda), Ostracoda(Conchoecia spp.) and Pteropoda (Limacina sp.) are permanentthroughout the year, and maximum in summer. The vertical distributionof zooplankton depends on the hydrological structure, i.e. natureof the water mass and degree of mixing between different waters.Brazil current water, with low quantity of organisms and dominanceof copepods (Clausocalanus furcatus, Mecynocera clausi, Corycaeidae,Oithonidae, Oncaeidae) accompanied by Evadne spinifera and Lucifertypicus. South Atlantic Central Water (upwelling water) characterizedby rare deep copepods and abundance of Calanoides carinatusand Ctenocalanus vanus which are excellent indicator speciesfor upwelling occurrence. Coastal water, with low salinity,where some species with brackish affinity are observed, likeOithona ovalis and Podon polyphemoides.     

Intracellular crystal-bearing vesicles in the epidermis of scleractinian corals, Astrangia danae (Agassiz) and Porites porites (Pallas).

Orthorhombic aragonitic crystals, embedded with a granular lipo-protein matrix and surrounded by a trilaminar membrane, are localized in the apical cytoplasm of epidermal cells of Scleractinian corals. Adult specimens of Astrangia danae (Agassiz) and settled planulae of Porites porites (Pallas) contain crystals averaging 0.7 mu by 0.1 mu by 0.3 mu within Golgi-derived vesicles. Short-term labelling with 45Ca reveals distribution of radioactivity amont a basic tissue fraction (92%) an acid tissue fraction (5%) and a skeletal fraction (3%). Identification of the primordial crystal population within membrane-bound visicles provides overwhelming evidence for the intracellular mode of calcification in Scleractinia. Moreover, it permits development of a novel concept of cellular regulation over these dynamic events. The membrane-bound vesicel is a miniature crystal fabrication station and a vehicle responsible for transportation of seed crystals and an organic matrix material to sites of discharge from the cell. The vesicle membrane becomes a probable locus of active transport and enzymatic activity as well as a physical barrier to be penetrated for release of vesicle contents into the extracellular milieu. Contact between the vesicle membrane and the plasmalemma would result in exocytosis and the onset of skeletogenesis. Principles governing crystal growth would prevail from then on. The released crystal becomes a nucleation catalyst and the organic matrix, a supply of ionic calcium for self-limiting crystallization. Crystals are produced by the organism spontaneously and continuously from shortly after larval attachment throughout the life of the polyp. Therefore, these membrane-bound vesicles signal the dynamic process by which initiation, differentiation, growth and limitation of the coral skeleton is regulated.