ALBERT

Description: The relation of two well-known ancient carbonate deposits to hydrocarbon seepage was confirmed by this study. Archaea are found to be associated with the formation of Oxfordian seep carbonates from Beauvoisin and with a Miocene limestone from Marmorito ("tube-worm limestone"). Carbonates formed due to a mediation by archaea exhibit extremely positive or extremely negative 813Ccarbonate values, respectively. Highly positive values (+ 15%0) reflect the use of 13C-enriched CO2 produced by methanogenesis. Low 813C values of the Marmorito carbonates (-30%0) indicate the oxidation of seepagederived hydrocarbons. Likewise, the 813C content of specific tail-to-tail linked isoprenoids, biomarkers for archaea, was found to be strikingly depleted in these sampies (as low as -115%0). The isotopic signatures corroborate that archaea were involved in the cycling of seepage-derived organic carbon at the ancient localities. Another Miocene limestone ("Marmorito li mestone") shows a strong imprint of methanotrophic bacteria as indicated by 813C va lues of carbonate as low J. Peckmann (IEI) . J. Reitner Institut und Museum für Geologie und Paläontologie, Georg-August-Universität. Goldschmidtstrasse 3, D-37077 Göttingen, Germany e-mail: jpeckma@gwdg.de. Fax: + 49-551-397918 V. Thiel, W. Michaelis Institut für Biogeochemie und Meereschemie, Universität Hamburg, Bundesstrasse 55, D-20146 Hamburg, Germany P. Clari, L. Martire Dipartimento di Scienze della Terra, via Accademia delle Scienze 5, 1-10123 Torino, Italy C. Gaillard UFR des Sciences de la Terre, UMR 5565 Centre de Paleontologie stratigraphique et Paleoecologie, Universite Claude Bemard, Lyon 1, 27-43 Boulevard du 11 Novembre, F-69622 Villeurbanne Cedex, France as -40%0 and biomarker evidence. Epifluorescence microscopy and field-emission scanning electron microscopy revealed that bacterial biofilms were involved in carbonate aggregation. In addition to lucinid bivalves previously reported from both localities, we infer that sponges from Beauvoisin and tube worms from Marmorito depended on chemosynthesis as weil. Low 813C values of nodules related to sponge taphonomy (-27%0) indicate that sponges might have been Iinked to an enhanced hydrocarbon oxidation. Tube worm fossils from Marmorito closely resemble chemosynthetic pogonophoran tube worms from Recent cold seeps and are embedded in isotopically light carbonate (813C -300/00).

Description: Colonial non-zooxanthellate corals from deep-water coral reefs, Lophelia pertusa and Madrepora oculata, produce large amounts of extracellular mucus (EMS). This mucus has various functions, e.g., an antifouling capability protecting the coral skeleton from attacks of endolithic and boring organisms. Both corals show thick epithecal and exothecal skeletal parts with a clear lamellar growth pattern. The formation of the epitheca is unclear. It is supposed that the EMS play a central role during the calcification process of the epithecal skeletal parts. Staining with the fluorochrome tetracycline has shown an enrichment of Ca2+ ions in the mucus. In order to investigate this hypothesis, the protein content of the mucus and the intracrystalline organic matter from newly formed epithecal aragonite of Madrepora oculata was determined via sodium dodecyl sulfate (SDS) gel electrophoresis. Identical band patterns within both substances could be detected, one around 45 kDa molecular weight and a cluster around 30-35 kDa molecular weight. The occurrence of identical protein patterns within the mucus and in the newly formed aragonite confirms the idea that the mucus plays an important role during the organomineralization of the coral epitheca.

Description: The Satonda crater lake is up to now the only known "marine" lake with an increased alkalinity compared to seawater. Therefore, the lake contains a decreased amount of Ca2 +. Its pH values about 8.5-8.6. The lake was originally filled with freshwater, which is evident from peat deposits (3,150 14C_yrs BP). Shortly after the lake was rapidly filled with seawater and a marine fauna had established. Large input of organic matter has caused an intense oxygen consumption and, as a result, the bottom water of the lake became anaerobic. Thus, an intense sulfate reduction occurred producing high amounts of bicarbonate ions. The lake became stratified into three water bodies with various salinities separated by two pycnoclines. The surfaces water body is oxygenated and exhibits brackish conditions. The algae/microbialite reefs exhibit avertical development which started with a serpulid framework, followed by loose crusts of the calcified red alga Peyssonnelia and thalli of the green alga Cladophoropsis calcified by cyanobacteria (microstromatolites). The top calcified layer is formed by a network of Lithoporella, Peyssonnelia and microbialites. On the top layer the living reef community is located.

Description: We propose that organic compounds found in a Miocene limestone from Marmorito (Northem Italy) are source markers for organic matter present in aneient methane vent systems (cold seeps). The limestone contains high concentrations of the tail-to-taillinked, acyclic C20 isoprenoid 2,6,11,15-tetramethylhexadecane (crocetane), a C25 homolog 2,6,10,15,19-pentamethylicosane (PME), and a distinctive glycerol ether lipid containing 3,7,1l,15-tetramethylhexadecyl (phytanyl-) moieties. The chemical structures of these biomarkers indicate a common origin from archaea. Their extreme1y l3C-depleted isotope compositions (813C "'" -108 to -115.6%0 PDB) suggest that the respective archaea have directly or indirectly introduced isotopically depleted, methane-derived carbon into their biomass. We postulate that a second major cluster of biomarkers showing heavier isotope values (8l3C "'" -88%0) is derived from sulfate-redueing bacteria (SRB). The observed biomarkers sustain the idea that methanogenic bacteria, in a syntrophic community with SRB, are responsible for the anaerobic oxidation of methane in marine sediments. Marmorito may thus represent a conceivable aneient scenario for methane consumption performed by a defined, two-membered bacterial consortium: (1) archaea that perform reversed methanogenesis by oxidizing methane and produeing CO2 and H2; and (2) SRB that consume the resulting H2. Furthermore, the respective organic molecules are, unlike other compounds, tightly bound to the crystalline carbonate phase. The Marmorito carbonates can thus be regarded as "cold seep microbialites" rather than mere "authigenic" carbonates.

Description: : From the Early Aptian ("Töck") of Heligoland (North Germany) three new species, one new genus and one new family of Teuthids are described: M astigophora stuehmeri n. sp., Boreopeltis helgolandiae n. gen. n. sp. and Maioteuthis damesi n. sp. The new genus Boreopeltis n. gen. ist placed in the family Plesioteuthididae NAEF 1921. The genus Mastigophora OWEN 1856 previously attributed to the family Loligosepiidae VAN REGTEREN ALTENA 1949 is proposed as type genus of the new family Mastigophoridae. Two poorly preserved specimens cannot"be identified specifically (?Trachyteuthis sp. and Plesioteuthis sp.). Kurz fas sung: Aus dem Unterapt (»Töck«) von Helgoland werden drei neue Arten, eine neue Gattung und eine neue Familie von Teuthiden beschrieben: M astigophora stuehmeri n. sp., Boreopeltis helsolandiae n. gen. n. sp. und Maioteuthis damesi n. sp. Die Gattung Boreopeltis n. gen. wird zur Familie PleslOteuthididae NAEF 1921 gestellt. Die Gattung Mastigophora OWEN 1856, bisher zur Familie Loligosepiidae VAN REGTEREN ALTENA 1949 gestellt, wird zur Typusgattung der neuen Familie Mastigophoridae vorgeschlagen. Zwei weitere Exemplare können nicht näher bestimmt werden (?Trachyteuthis sp. und Plesioteuthis sp.).

Description: Three new genera of endocochleate cephalopods from the Lower Devonian cast new light on the evolution of modern and fos sil coleoids. Protoaulacoceras n. g. represents the r03trum-bearing line of aulacocerid-belemnitid type, while the ontogeny shows still features of the michelinoceratid ancestors. In contrast, Boletzkya n. g. and Naefiteuthis n. g., in which the chambered part of the shell looses its function during ontogeny, show a trend towards Mesozoic Loligosepiidae and recent teuthids.

Description: Die neuen Formen endocochleater Cephalopoden aus dem Unterdevon werden die Vorstellungen über die Evolution der fossilen wie auch der modernen Cephalopoden verändern. Im Falle von Protoaulacoceras n. g. handelt es sich um eine r03trumtragende Form, wie die späteren Aulacocerida und Belemnitida, deren Gehäusejugendstadien noch den michelinoceratiden Vorfahren gleicht. Die Gattungen Boletzkya n. g. und Naefiteuthis n. g. zeigen dagegen eine Entwicklung in Richtung auf die mesozoischen Loligosepiidae und Verwandte und die rezenten Teuthiden, indem der gekammerte Teil der Schale während der OntOgenese immer stärker reduziert wird.

Description: The lipid assemblages of the "living fossil" stromatoporoid Astrosclera willeyana (Great Barrier Reet) and the demosponge Agelas aroides (Mediterranean Sea) were investigated. Large amounts of branched carboxylic acids are present in the sponges studied. These compounds include terminally branched carboxylic acids (isa -/anteisa-) and abundant mid-chain branched carboxylic acids (MBCA) wh ich are characterized by an intriguing variety of structural isomers present in the C 15- C25 range. The most prominent MBCA are comprised of isomeric methylhexadecanoic acids and methyloctadecanoic acids. A second cluster of MBCA includes methyldocosanoic acids and methyltetracosanoic acids, but other homologues are also present. Methyl branching points were generally observed between the w5- and w9-positions. These complex isomeric mixtures apparently derive from symbiotic bacteria living exclusively in demosponges. Comparison with hydrocarbon compositions of ancient carbonates reveals evidence that the MBCA found are potential lipid precursors of mid-chain branched monomethylalkanes often observed in fossil sediments and oils. As a working hypo thesis, we suggest that their bacterial source organisms have been widespread in the geological past, and are found " inherited" in the protective environment of distinctive sponge hosts in recent marine ecosystems. Furthermore, both sponges contain abundant linear, longchain C24- C26 dienoic "demospongic" acids. The demospongic acid distribution and the presence of phytanic acid in A. willeyana match the patterns found in A. aroides and other members of the Agelasida. These findings confirm the systematic position of A. willeyana within this demosponge taxon.

Description: The crater lake of the small volcanic island Satonda, Indonesia, is unique for its red-algal microbial reefs thriving in marinederived water of increased alkalinity. The lake is a potential analogue for ancient oceans sustaining microbialites under open-marine conditions. Current reef surfaces are dominated by living red algae covered by non-calcified biofilms with scattered cyanobacteria and diatoms. Minor CaCO3 precipitates are restricted to the seasonally flooded reef tops, which develop biofilms up to 500 mm thick dominated by the cyanobacteria Pleurocapsa, Calothrix, Phormidium, and Hyella. Microcrystalline aragonite patches form within the biofilm mucilage, and fibrous aragonite cements grow in exopolymer-poor spaces such as the inside of dead, lysed green algal cells, and reef framework voids. Cementation of lysed hadromerid sponge resting bodies results in the formation of ‘‘Wetheredella-like’’ structures. Hydrochemistry data and model calculations indicate that CO2 degassing after seasonal mixis can shift the carbonate equilibrium to cause CaCO3 precipitation. Increased concentrations of dissolved inorganic carbon limit the ability of autotrophic biofilm microorganisms to shift the carbonate equilibrium. Therefore, photosynthesis-induced cyanobacterial calcification does not occur. Instead, passive, diffusioncontrolled EPS-mediated permineralization of biofilm mucus at contact with the considerably supersaturated open lake water takes place. In contrast to extreme soda lakes, the release of Ca21 from aerobic degradation of extracellular polymeric substances does not support CaCO3 precipitation in Satonda because the simultaneously released CO2 is insufficiently buffered. Subfossil reef parts comprise green algal tufts encrusted by microstromatolites with layers of fibrous aragonite and an amorphous, unidentified Mg–Si phase. The microstromatolites probably formed when Lake Satonda evolved from seawater to Ca21-depleted raised-alkalinity conditions because of sulfate reduction in bottom sediments and pronounced seasonality with deep mixing events and strong CO2 degassing. The latter effect caused rapid growth of fibrous aragonite, while Mg–Si layers replaced the initially Mg-calcite-impregnated biofilms. This could be explained by dissolution of siliceous diatoms and sponge spicules at high pH, followed by Mg-calcite dissolution and Mg-silica precipitation at low pH due to heterotrophic activity within the entombed biofilms.

Description: Sponges and coralomorphs were sessile epibenthic suspension feeders living in normal marine environments. Sponges with calcified skeletons, induding archaeocyaths, mainly inhabited shallow to subtidal and intertidal domains, while other sponges occupied a variety of depths, including slopes. The high diversity .of sponges in many Cambrian Lagerstätten suggests that complex tiering and niche partitioning were established early in the Cambrian. Hexactinellida were widespread in shallow-water conditions from the Tommotian; some of them may have been restricted to deepwater environments later in the Cambrian. Calcareans (pharetronids), together with solitary coralomorphs, thrived in reef environments, mostly in cryptic niChes protected from very agitated waters. Rigid demosponges (anthaspidellids and possible axinellids) appeared by the end of the Early Cambrian and inhabited hardgrounds and reefs from the Middle Cambrian. The overall diversity of sponge and coralomorph types indicates that during the Cambrian these groups, like other metazoans, evolved a variety of architectural fonns not observed in subsequent periods.

Description: Sponges are primitive metazoan organisms which occur since the late Proterozoic. The oldest sponge remains (hexactinellids) are from a shallow marine carbonate facies of the late Sinian Shibantan Member (China). From the Tommotian (Sansha, China) protospongiid and rossellimorph hexactinellids were discovered in shallow marine silicified rocks. The middle part of this section consists of silty shales with entirely preserved hexactinellid sponges: Sanshadictya, Hyalosinica, Solactinella, Triticispongia, Hunanospongia. The hexactinellids typically are soft bottom dwellers, which sometimes grow on and form in situ spiculites (spicule mats). The sponges from the Chengjiang deposits of Atdabanian age, which show a rossellimorph spicule organization typical of the conservative hexactinellid groups, which inhabited the deep sea during most of the Phanerozoic, were also typical soft bottom dwellers. All sponge taxa (Leptomitella, Leptomitus, Paraleptomitella etc.) described from this locality we consider to be hexactinellids and not demosponges, as originally classified. The sponge communities of carbonate-dominated archaeocyathid mounds are completely different from the above described sponge mounds. The sponges from the archaeocyath mounds of the Flinders Ranges (S.Australia) are characterized by Calcarea and demosponges ($; modern type of pharetronid Calcarea Gravestockia pharetroniensis, and many tetractinellid demosponges, Geodiida). Questionable is the origin of four-rayed demosponge spicules found in some archaeocyaths. The oldest ceractinomorph demosponges are documented from the middle Cambrian (Vauxia - an aspicular sponge with keratose affinities, and isolated sigmata microscleres). Sponge communities of the Early Cambrian were highly developed, and already then they were taxonomically strongly dependent on substrates and trophic conditions.

Description: Schwammfragmente (Hexactinelliden) stammen aus einer flachmarinen Karbonatfazies im späten Sinium des Shibatan Members in China. Aus dem Tommotium (Sansha, China) wurden protospongiide und rossellimorphe Hexactinelliden innerhalb flachmariner, verkieselter Gesteinsformationen entdeckt. Der mittlere Abschnitt dieses Profils besteht aus siltigem Tongestein mit körperlich erhaltenen hexactinelliden Schwämmen: Sanshadictya, Hyalosinica, Solactinella, Triticispongia, Hunanospongia. Die Hexactinelliden sind typische Weichbodenbewohner, die manchmal in-situ-Spiculite (Spicula-Matten) bilden und auf diesen wachsen. Die Schwämme der Chengjiang Lagerstätte (Atdabatium), die eine • rossellimorphe Sklerenanordnung, typisch für konservative Hexactinellidengruppen des tieferen Wassers während des Phanerozoikums, zeigen, waren ebenfalls charakteristische Weichbodenbewohner. Alle Spoilgien-Taxa, die von dieser Lokalität beschrieben sind (Leptomitella, Leptomitus, Paraleptomitella, ect.), werden von uns als Hexactinellida angesehen und nicht als Demospongiae, wie sie sie ursprünglich klassifiziert wurden. Die Schwamm-Gemeinschaften der karbonatreichen Acrchaeocyathidenmounds unterscheiden sich von den oben beschriebenen Spongien mounds signifikant. Die Schwämme aus den Archaeocyathenmounds der Flinders Ranges (Südaustralien) sind charakteristischerweise Calcarea und Demospongiae (pharetronide Calcarea von "moderner" Organisation wie Gravestockia pharetroniensis und viele tetractinellide Demospongiae der Geodiida). Umstritten bleibt der Ursprung der vierstrahligen demospongiiden Spicula, die in einigen Archaeocyathen gefunden wurden. Die bisher ältesten ceractinomorphen Demospongien sind aus dem mittleren Kambrium nachgewiesen (Vauxia - ein aspikulärer Schwamm mit Affinität zu den Keratosen, und isolierte Sigmata\ Mikroskleren). Spongien-Gemeinschaften des frühen Kambriums waren hochentwickelt und in ihrer taxonomischen Zusammensetzung schon damals sehr vom Substrat und Nahrungsangebot abhängig.

Description: Morphological and geochemical comparisons between modern cryptic microbialites from Lizard Island/Great Barrier Reef and fossil counterparts in the Upper Jurassic (Southern Germany, Dobrogea/Romania) and late Lower Cretaceous (Aptian/ Albian from Cantabria/Spain) spongiolitic environments show that there are common factors controlling the crust formations mostly independent of light despite of diverging (paleo-) oceanographic positions as well as relationships of competitors. Factors such as increased alkalinity ,oligotrophy, and reduced allochthonous deposition are of major importance. Thrombolitic microbialites are interpreted as biologically induced and therefore calcified in isotopic equilibrium with the surrounding sea water. Corresponding with shallowing upward cycles, microbial mats which produce stromatolitic peloidal crusts become more important. Different biomarkers are introduced for the first time extracted and analyzed from spongiolitic limes tones ofLower Kimmeridgian age from Southern Germany.

Description: Our paper (Arp et al. 2003) revises previous studies of Kaz´mierczak and Kempe (1990, 1992), Kempe and Kaz´mierczak (1990a, 1990b, 1993), and Kempe et al. (1996, 1997) on Lake Satonda reefs with regard to biofilm calcification and microbialite formation. We confirm that the transfer of bottom waters of increased alkalinity (due to sulfate reduction) to shallow water layers (mixolimnion) principally can support or cause biofilm calcification and microbialite formation in shallow waters (as suggested by Kempe 1990). However, their two-stage model of microbialite formation in Lake Satonda, which claims that superficial in vivo permineralization of coccoid cyanobacterial colonies by high-Mg calcite is followed by internal fibrous aragonite growth due to anaerobic decay of the entombed colonies to form microstromatolites (Kaz´mierczak and Kempe 1990) as well as Wetheredella-like structures (Kaz´mierczak and Kempe 1992) is a theoretical construct without supporting evidence from data and observations from Satonda crater lake. Also, the comparison of Lake Satonda stromatolitelike encrustations on green algae with early Paleozoic stromatoporoids by Kaz´mierczak and Kempe (1990) lacks—in our opinion—any supporting evidence. In their discussion, Kaz´mierczak and Kempe reiterate allegations seemingly supported by images and data. At a closer look, results obtained from inadequately treated samples (air drying, etching fractures, or cutting planes), a tendentious identification of coccoid structures, analytical failures (basic mineralogy from EDX measurements), and biased consideration of data (supersaturation) results in theoretical misconceptions of post-mortem calcification of degrading cyanobacterial colonies. Our positions and arguments follow.

Description: A new species of a coralline sponge, Cassianothalamia zardinii n. gen. n.sp., from the Lower Carnian Cassian Beds (northern Italy) is described. The new species possesses a secondary thalamid basal skeleton with a spongocoel and the internal structure is constructed of horizontal elements (trabecula) and vesiculae. The microstructure of the basal skeleton is composed of an irregular high Mg-calcite. From the spicular skeleton aster-microscleres can be preserved. In rare cases, monaxonid megascleres can also be found. Therefore the new sponge is probably a representative of the demospongid order Hadromerida.

Description: Une nouvelle espece d'eponge coralline, Cassianothalamia zardiini n.gen. n.sp., a ete trouvee dans les couches du Carnien inferieur de Saint-Cassian. La nouvelle espece possede un squelette basal thalami de secondaire muni d'une cavite pseudogastrique et sa structure interne est constituee d'eIements horizontaux (trabecules) et de vesicules. La microstructure de la partie basale du squelette est composee d'une calcite irreguliere a forte teneur en Mg. Les microscleres asteroYdes du squelette spiculaire peuvent avoir ete conserves. On peut aussi trouver tres rarement des megascleres monaxonides. Par consequent, cette nouvelle eponge est probablement un representant de l'ordre Hadromerida des Demosponges.

Description: From the Lower Toarcian near Holzmaden (Southwest Germany) belemnites, Acrocoelites (Toarcibelus) raui und Passaloteuthis paxillosa, with softpart preservation are described. The specimens show ten arms with double rows of hooks, jaw, mantle muscle, ink sac and lateral fields of the proostracum.

Description: Aus dem Untertoarcium der Gegend von Holzmaden (Südwestdeutschland) werden Belemniten, Acrocoelites (Toarcibelus) raui und Passaloteuthis paxillosa, mit Weichteil resten beschrieben. An diesem Exemplaren werden nachgewiesen: Zehn Arme mit Doppelreihen von Fanghaken, Kiefer, Mantelmuskel, Tintenbeutel und Seitenfelder des Proostrakums.

Description: Während einer 9-tägigen Exkursion auf dem Baikal-See vom 2.-10. September 1993 wurden mehrere Proben der endemischer Baikal-Schwämme (Lubomirskiidae) Swartschewskia papyracea, Lubomirskia baicalensis und Baikalospongia cf. bacillifera genommen und histologisch und ultrastrukturell in Hinblick auf die Morphologie der Choanocytenkammern und der Choanocyten, auf Embryonal- und Larvalstadien, Struktur und Anordnung der Spicula sowie den Kontakt zwischen Substrat und Schwamm untersucht. Die Choanocyten aller untersuchten Arten der Lubomirskiidae wiesen ähnliche morphologische Merkmale auf. Das Flagellum ist in einer kleinen Grube eingelenkt. Der Basalkörper (Kinetosom) ist mit senkrecht zu ihm verlaufenden Mikrotubuli verankert. Im September befanden sich in einer Probe von Baikalospongia cf. bacillifera bereits ausdifferenzierte Parenchymula-Larven, während in Swartschewskia papyracea nur Furchungsstadien und in Lubomirskia nur Eizellen angetroffen werden konnten. An den Substratansatzstellen wurde ein Biofilm nachgewiesen.

Description: During a 9-day excursion at the beginning of September 1993 to Lake BaikaI (Sibiria) several sam pies of the endemic Baikal-sponges (Lubomirskiidae) Swartschewskia papyracea, Lubomirskia baicalensis, and Baikalospongia cf. bacillifera were collected and afterwards examined at histological and ultrastructural level. Special interest was focused on the morphology of choanocyte-chambers and choanocytes, embryonal stages, larvae, spicules, and the contact between the substrate i}nd the sponge. All choanocytes of the examined lubomirskiid species showed similar mOrphologicai patterns. The flagellum is located in a little pit and the kinetosome anchored with microtubules. In September Baikalospongia contained allready fully developed Parenchymellae, while Swartschewskia exhibited cleavage stages and Lubomirskia large oocytes only. Between sponge and substrate a biofilm-layer was detected.

Description: PalaeobiologicaJ models of four selecled species of sphinctozoan coraIIine sponges from the Cassian Ileds (Lower Camian, Dolomites) have been established using, among othels, luminescence tecbniques. The latter has beeil Sllccesfully to wimate the organie content and diagenetic history ofthe skeletons. Recent in"estigations yield the differentiation ofthree steps in the secretion ofthe skeleton in coralline sponges, according to which skelelal elements can be classified. The identification of these elements rendels infoiiuation on the way ofsecretion ofthe skeleton, the relative position ofthe soft tissue, and the function ofthe skeleton. Two basic type.s of sphinctozoan organisation can be distinguished: a matrix type, where a rigid framework, secreted in an organo-spicular matrix peneti"ates the soft t.issue (as in suomatoporoid coralline sponges) and a cortex type, where the skeleton is secreted by a speziali'WI layer (cortex) surrolmding the sponge body. These organizational types bear no phylogenetic implication.

Description: Es wurden paläobiologische Modelle von vier ausgewählten Arten sphinctozoider Schwälluue alls den Cassianer Schichten (Unteres Kam, Dolomiten) unter Zuhilfenalime von I ~lmineszenZll\ethoden eisIeIlt. Diese konnten mit Erfolg zur Abschätzung des Gehalts an organischen Stoffen und der diagenetischen Geschichte der Basalskelette eingesetzt werden. Neuere Untersuchungen erlauben die von drei Schritten in der Genese des Basalskeletts der corallinen Schwämme, die zu einer Klassifikation der Skelettelemente herangezogen werden können. Eine Identifikation der jeweiligen Elemente entsprechend dieser Klassifikation liefert Infoiinationen über die Art der Sekretion des Basalskeletts, die relative Position des Lebendgewebes und die Funktion des Skeletts. Zwei gnmdlegende Organisalionstypen können innelhalb der Sphinctozoen unterschieden werden: ein Matrix-Typ, bei dem das in einer organo-spikulären Matrix sekretiert wird, die den Weichkölper durchzieht (ähnlich den stromatoporoiden "CoraIline Spongien") lind ein Cortex-Typ, bei dem die Sekretion des Basalskeletts in einer spezialisierten, subdeiioalen Schicht (Cortex), die den Weichkölper umgibt, stattfindet Diese Organisationstypen haben keine Implikationen.

Description: From shallow water caves of fringing reefs related to continental islands of the Lizard Island Section thrombolitic micritic microbialites were observed. The microbialites exhibit always a light decreasing facies succession. The succession starts with a coralgal community and ends with light independent microbial biofilms and benthos (coralline sponges). The sessile mineralized benthos community is constructed of crustose foraminifera, serpuli$, thecidean brachiopods, bryozoans, and coralline sponges. The observed benthic community is very similar 10 thoseone bbserved in cryptic habitates of Aptian and Albian reefs of northem Spain. For longtime studies of the m~crobialite formation and growth rates of coralline sponges the specimens were stained in vivo, within their natural habitat with histochemical fluorochromes and nonfluorescent agents. Main results are a very slow growth of the microbialite and associated sponges (50-100 Ilm/y). Only few calcifying microbes are participators during microbialite formation. Calcifying acidic organic macromolecules are mainly responsible for microbialite formation by cementing detritical material. FelMn-bacterial biofilms are responsible for strong corrosion of the microbialite. Beside the corrosive activity of the Fe/Mn-bacterial biofilms boring sponges (Aka, Cliona) are the main destructors. The investigations began in 1990 with a pilot study in fringing reefs of Lizard Island (Great Barrier Reef) and reefs of the outer barrier for comparison. Main goals are to study this environment under normal conditions and for comparison under controlled artificial conditions in seawater running aquaria. Two reef caves were selected for longtime research and all experiments were carried out within these caves. H.ZANKL(Marburg)hasrecentlyfoundnearly similar microbialites in cryptic habitates of reefs of St.Croix (US Virgin Islands, central Caribbean realm) (ZANKL 1993). Comparative fossil examples were studied by NEUWEILER (1993) on middle Albian reefs of northem Spain and KEupp et al. (this volume) for Jurassic ones. Both studies refer to the presented data. Purpose of this study is to demonstrate the growing procedure of a modem type of cryptic, light independent microbialite, the interaction with associated benthos, and its significance as a key facies to understandfossil metazoan-micriticl microbialitereefs. To understand these very complex processes it is neecessary to review and compile modem concepts of biomineralisation, biofilms, and e.g. the alkalinity question. Therefore mixing of own results and reviews is planned and intended! Main goal of this study is creation of a working hypothesis to understand the processes of formation of micritic/microbial build ups ("mud mounds"). Geochemically the observed microbiali tes are composed of mainly high-Mg calcites and exhibit high positive ö13C (+3 to +4) values.

Description: Die Eischalenstruktur von Varanus komodoensis OUWENS 1912 (Komodowaran) wird mit verschiedenen Methoden untersucht (REM. Dünnschliffe. histologische Methoden. Fluorochromierungen. EDAX) und dokumentiert. Sie besteht aus einem wellblechartig arrangierten Geflecht organische Fasern. in die zentral eine Lage kalzitischer Sphärolithe integriert ist. Zusätzlich findet Mineralisation in kesseiförmigen Einheiten statt, in denen Kalzitkristalle die Anlage der Fasern nachzeichnen. Die Oberfläche der Schale wird durch eine dünne Schicht aus radialen bis mehr oder weniger kugeligen Kieselsäure-Aggregaten bedeckt. Der Vergleich mit den Eischalen von drei Varanus-Arten und anderen Squamaten zeigt. daß die Schalenstrukturierung auch unter funktionsmorphologischen Aspekten erfolgt.

Description: Eggshell structure of Varanus komodoensis OUWENS 1912 (Komodo monitor) is analyzed using different methodes (SEM, thin sections, histological staining, fluorochromes, EDX) and documented. The shell consists of wavy organic fibres. Within the shell, a distinct layer of calcitic spherules can be recognized. Additionally, bigger kettle-like objects are fully mineralized, reflecting the wavy structure of the fibres. The outer surface of the shell is covered by a thin layer consisting of amorphous silica. The shell is compared with three other species of Varanus and other squamatic reptiles.

Description: Available evidence suggests that the first demosponges occur in the Late Proterozoic, with forms characterized by bundles of long monaxonic spicules. In the Middle Devonian the first modern forms of Dendroceratida, ‘axinellids’ (mostly halichondrids), and first haplosclerids appeared. An important boundary for the demosponges is the Late Devonian extinction event, which caused a complete overhaul of demosponge communities. The Late Permian and the Triassic, especially the Late Triassic, are the main eras for coralline demosponge radiation and dominance, in which some modern taxa occur for the first time (Ceratoporella, Astrosclera, Vaceletia). In the Late Jurassic the freshwater environments were occupied by certain (marine) demosponges, mostly Haplosclerida. The importance of coralline demosponges as primary reef-builders decreases up to the Late Cretaceous.

Description: The monophyly of the Porifera is weil established. According to our hypothesis the Hexactinellida are the adelphotaxon of the Pinacophora (new taxon = Calcarea + Homoscleromorpha + Demospongiae). The Porifera are the adelphotaxon of the Eumetazoa/Placozoa. Sponge spicules are considered not to be a constituent character of the Porifera. Mineralized spicules developed independently within the three poriferan main taxa the Hexactinellida, Calcarea, and Demospongiae. Demospongian microscleres are not derived from megascleres in contrast to those of Hexactinellida. Accordingly, spicules probably developed several times within the Demospongiae. Remains of Porifera are known since the late Proterozoic.

Description: The large sandy desert of Badnin Jaran Shamo, Inner Mongolia, has several salt lakes located among megadunes with crests as high as 400 m. Most of the lakes are hypo- to hypersaline and alkaline, with pH values between 8.5 and 10. Because of their reef-like aragonitie pinnacles rising from the lake floor, Lake Nuoertu and Lake Huhejaran haue been investigated in detail. The porous limes tones of the tufa pinnacles ("spring mounds'') result {rom a hydrochemieally forced, exopolymer-mediated calcification of cyanobacteria- dominated mierobial mats at sublacustrine springs. The development oftheir enigmatie fabries is documented for the first time. Siekle-cell-like and bubbleshaped fabries reflect successive mineralization during degradation, shrinkage of the organie mucus, and gas formation by bacteria. Fossil analogues are known from the Pleistocene and Miocene (Ries-crater lake), but older non-marine, Phanerozoie examples are expected. 1b the extent that these textures are associated exclusively with alkaline environments, they can be used to test the hypothesis of an alkali ne ocean early in Earth history.

Description: The polyphyletic coralline demosponges possess a calcareous basal skeleton of 4 major morphotypes. Each has its own phylogenetic history, with different mechanisms of formation. One extant taxon of each skeletal type has been investigated, and its biochemical (e.g., intracrystalline organic matrix proteins), geochemical (e.g., stable isotopes), and histological properties described in detail. The thalamid Vaceletia shows similarities in its skeletal features to extinct archaeocyathid sponges due to the presence of special Ca2+ waste deposit chambers in the lower part of the skeleton. In our opinion this type is phylogenetically the most important one because it represents one possible evolutionary way of Ca2+ detoxification and iIIustrates one function of basic biomineralization (Ca2+-detoxification). More sophisticated biomineralization processes are developed in the agelasid Ceratoporella, the "chaetetid" hadromerid sponge Spirastrella (Acanthochaetetes) weil si, and the "stromatoporoid" agelasid Astrosclera willeyana. Each of these taxa shows a distinct process of formation with a unique composition of its intracrystalline organic matrix and geochemical features, here characterized in detail. A model of phylogenetic relationships and grades of development is proposed. The first metazoans with CaC03 biomineralization were the worm- like Cloudinidae from the late Sinian, which form a tube with a foliated structure. However, the taphonomy- controlled mode of basal skeleton formation in Archaeocyatha and Vaceletidae is the most ancient type of biologically- controlled metazoan biomineralization. In general, basal skeletons of coralline sponges represent the simplest biologically controlled mineralization, intermediate between biologically induced type (e.g., organomineralization) and the fully enzymatically- controlled mineralization of higher Metazoa.

Description: Astraeospongium is found to form secondary calcareous basal skeletons and thus may be attributed to the morphological grouping "coralline sponges". In A. meniscum, a bowl-shaped sponge with a massive skeleton of octactins, the ontogenetically youngest and still uncemented spicules are found at the upper, concave surface, particularly close to the edge. Towards the bottom, the spicules soon become altered through epitaxic cementation and recrystallization. From this skeletal architecture can be inferred that the soft tissues occupied only the uppermost portions of the basal skeleton. The skeletal structure is in many respects similar to that of the recent Petrobiona massiliana, although the ecological adaptations of the two species are fundamentally different.

Description: Astraeospongium bildet ein sekundäres kalkiges Basalskelett und kann somit der morphologischen Gruppierung "koralline Spongien" zugerechnet werden. In A. meniscum, ein schüsseIförmiger Schwamm mit einem massiven Skelett aus Octactinen, befinden sich die ontogenetisch jüngsten und noch unzementierten Spicula an der oberen, konkaven Seite, insbesondere nahe dem Rand. Zum Basis hin ändern sich bald die Spicula durch epitaktische Zementation und Rekristallisation. Aufgrund dieser Skelettarchitektur kann geschlossen werden, daß sich der Weichkörper nur in den obersten Bereichen des Skeletts befand. Die Skelettstruktur ist der der rezenten Petrobiona massiliana in vielerlei Hinsicht ähnlich, wenngleich sich die ökologischen Anpassungen der beiden Arten grundlegend unterscheidet.

Description: Eine Faziesrekonstruktion W1d Korrelation obersinischer-unterkambrischer Schichten der Yangtze-Plattform (Südchina) wird vorgestellt. Dabei wird zwischen geschütztem Becken, Schwelle W1d tiefem Becken unterschieden. Die unterkambrische Schwarzschiefer-Transgression, der "Badaowan" Event, wird als diachron gekennzeichnet. Nach Untersuchungen der Lithologie W1d Geochemie der unterkambrischen Sedimente, vorwiegend Schwarzschiefer des Profils Sansha (nahe Dayong. N-Hunan), kann zwischen Sedimenten, die unter teilweise anoxischen Bedingungen oder im stagnierenden Becken abgelagert wurden, unterschieden werden. Schwammnadeln sind im untersten Unterkambrium Zentralchinas weit verbreitet. Neufimde vollständiger hexactinellider Schwämme Sanshadictya microreticulata gen. et sp. 0., Hyalosinica archaica gen. et sp.o., Triticispongia diagonata gen. et sp. n., Solactiniella plumata gen. et sp. 0., Hunanospongia sp. QIAN & DING, 1988, Hexactinellida indet., eines fraglichen vertreters der Demospongiae, Saetaspongia densa gen. et sp. 0. sowie eines Vertreters der Malacostraca Perspicaris sp., W1d einer unbenannten A1genfonn, werden vorgestellt. Schwammnadeln wurden ebenfalls neu in Gesteinen des Shibantan Mb. (Dengying Fm., Ob. Proterozoikum) vom Straßenaufschluß Liantuo (nahe Yichang. S-Hubei) gefunden. Die Fauna vorwiegend hexactinellider Schwämme von Sansha wird im Zusammenhang mit den taphonornisch AhnIichen Spongienfaunen des Red Hil1s Quarry (Mitteldevon, Nevada) und des Arnager Kalkes (Kreide, Bomholm) diskutiert.

Description: A facies reconstruction and correlation ofUpper Sinian - Lower Cambrian strata ofthe Yangtze platform (South China) is presented. Protected basin, uplift and deep basin development may be distinguished. The Lower Cambrian black shale transgression, the "Badaowan" Event, is characterized as diachronous. As a result of these investigations of lithology and geochemistry of the Lower Cambrian sediments (mainly black shales ofthe Sansha section, near Dayong. N. Hunan), sediments deposited under partially anoxic conditions or in a stagnant basin have been recognized. Sponge spicules are widely distributed in the lowennost Lower Cambrian of CentraI China. Recently discovered more or less complete sponges, including Sanshadictya microreticulata gen. et sp. 0., Hyalosinica archaica gen. et sp. 0., Triticispongia diagonata gen. et sp. 0., Solactiniella plumata gen. et sp. 0., Hunanospongia sp. QIAN & DING, 1988, Hexactinellida indet., a questionable demosponge, Saetaspongia densa gen. et sp. 0., and the Malacostraca Perspicaris sp., and an unnamed a1ga are described. Sponge spicules additionally were found in rocks of the Shibantan Mb. (Dengying Fm., Upper Proterozoic) from the road section of Liantuo (near Yichang. S.Hubei province). The fauna ofmainly hexactinellid poriferans from Sansha is discussed with regard to the similar taphonomy ofthe sponge faunas from the Red Hills Quarry (MiddIe Devonian ofNevada) and from the Arnager Iirnestooe (Cretaceous, Bomholm).

Description: Protein components found in freeze-dried specimens of the coralline sponge Spirastrella (Acanthochaetetes) wellsi were separated and characterized . Proteins extracted from skeleton crystals (matrix proteins) contained high concentrations of glycin (16 %) as weil as enhanced amounts of asparagin/aspartic acid (11 %) and glutamin/glutamic acid (10 %). At least 10 proteins could be separated by SDSPAGE. Six of them, with molecular weights between 30 and 45 kDa, may be considered as distinct matrix proteins. The bulk of total soluble proteins as weil as all soluble matrix proteins are acidic with pH values below 5. Our results indicate that at least in one stage crystal growth is matrix mediated, i.e. controlled by the sponge.