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The new genus Gosavisiphon with the type-species Halimeda paucimedullaris SCHLAGINTWEIT & EBLI, 1998, tentatively referred to the Udoteaceae, is described from the Late Cretaceous (Middle/Late Cenomanian-Santonian) of the Branderfleck Formation and the Lower Gosau Subgroup of the Northern Calcareous Alps (Austria, Germany). It is a plurimillimetric to pluricentimetric marine, hard-substrate dwelling macroalga, with membraneous and partly fused plates and an internal siphonaceous construction but lacking a real medullary zone. Although some thallus details are still unknown, Gosavisiphon gen. nov. can, from a strictly morphological point of view, directly be compared with the Late Palaeozoic and Upper Triassic phylloid algae. Gosavisiphon gen. nov. is the first fossil record of a platy siphonal alga in the Cretaceous, since the Late Triassic Ivanovia triassica REID. The monotypic taxon is most probably endemic to the Northern Calcareous Alps where it dwelled in protected, terrestrially influenced lagoonal environments attaching to hard substrates, (metazoan skeletons, rudistid shells). Based on findings of the cylindrical Halimeda? aff. johnsoni PAL and another taxon described as Halimeda sp. with typically flattened ovate segments, some considerations on the segment-morphological phylogenetic evolution of Halimeda LAMOUROUX are provided. Halimeda species with discoidal-flattened segments, that can morphologically be compared with extant species, are not known prior to the Turonian. Forms possessing cylindrical segments date further back, but can not directly be compared morphologically with modern counterparts, thus placing doubts on the existence of long-lasting methusalemi species by uniting extant and fossil species, as proposed by both botanists and palaeontologists in recent times. Source

Schlagintweit F.,Lerchenauerstr. 167 | Rigaud S.,University of Geneva | Wilmsen M.,Senckenberg Naturhistorische Sammlungen
Facies | Year: 2015

Rich and diverse trocholinid assemblages have been recorded from the lower to middle Cenomanian Altamira and Bielba formations of the Bascocantabrian Basin, northern Spain. They occur in bioclastic for-algal grainstones and near-reefal rudstones referred to platform margin environments. This material, partially impregnated by iron-rich solutions, is unusually well-preserved and offers the unique opportunity to carry out a detailed study of the last diversifed assemblages of the aragonitic foraminiferal order Involutinida. It notably allows (1) describing one new subfamily (Coscinoconinae n. subfam.), two new genera (Hensonipapillus n. gen. and Para -coscinoconus n. gen.), and five new species (Coscinoconus discoideus n. sp., Frentzenella pygmaea n. sp., Hensonipapillus cantabricus n. sp., H.altamirensis n. gen., n. sp., and Paracoscinoconus semiinvolutus n. sp.); (2) clarifying the relationship between the umbilical canal system and the laminar deposits in Late Jurassic–Cretaceous coscinoconins; (3) emending and providing new combinations for “Trocholina” lenticularis Henson, 1947 “T.” minima Henson, 1947 and “T.” burlini Gorbatchik, 1959 which have been repeatedly misidentifed in the literature; (4) discussing the epibenthic mode of life of trocholinids; and (5) proposing an explanation for their extinction at the Cenomanian–Turonian boundary. © Springer-Verlag Berlin Heidelberg 2014. Source

Schlagintweit F.,Lerchenauerstr. 167 | Rigaud S.,University of Geneva | Wilmsen M.,Senckenberg Naturhistorische Sammlungen
Cretaceous Research | Year: 2015

The small benthic foraminifera Altamirella biscayana n. gen., n. sp. is described from the lower Cenomanian of the Bielba and Altamira formations (North Cantabrian Basin, Spain). Its trochospirally coiled test combines calcitic dark microgranular and fibro-hyaline layers, an arrangement reminiscent of that observed in Palaeozoic Tetrataxidae Galloway. As in Tetrataxis, these layers are built in successive phases and never form a double-layer sensu stricto. The significance of this distinctive wall structure for taxonomy, phylogeny, dispersal, survival and ecology is discussed. A similar wall organization is also observed in some trochospirally coiled Mesozoic forms such as Mohlerina Bucur, Senowbari-Daryan and Abate and might be inherent to epibenthic taxa developing elevated microhabitats. © 2014 Elsevier Ltd. Source

Mohlerina basiliensis (Mohler, 1938) represents a common, cosmopolitan, shallow-water Middle Jurassic-Early Cretaceous trochospiral foraminifer. Given the numerous illustrations from thin-section specimens in the literature displaying tests dispersed within the matrix (micritic and sparitic), a free, vagile benthic mode of life is generally suggested. As an exceptional case, specimens are found with their tests attached to a variety of hard substrates, thus creating a special elevated microhabitat. The fixation is due to a calcitic cement. With its facultative sessile mode of life, Mohlerina can be compared with several modern calcareous trochospiral rotaliacean foraminifera (e. g., Ammonia, Cibicides, Discorbis). The rare preservation of fixed Mohlerina in situ is most likely due to physical taphonomic degradation (e. g., breakage). Tests of Mohlerina attached to hard substrates were found in both low- and high-energy paleoenvironments. The high test variability of Mohlerina might be influenced by the different settling strategies and substrate surface topographies within different paleohabitats. © 2012 Springer-Verlag. Source

Lithocodium aggregatum Elliott is interpreted as a heterotrichale chlorophycean alga with a prostrate and erect system within a well-calcified tissue. Within Lower Aptian coral rubble of the western Maestrat Basin, Spain, it forms thick masses of juxtaposed crusts around the bioclasts. In achieving a rapid and complete encrustation of the available bioclasts, Lithocodium applied several strategies, e. g., filling voids of structured surfaces with a special fabric or forming erect extensions to bridge adjacent substrates. In these deposits, different types of poorly if ever illuminated cryptic microhabitats can be distinguished: (1) existing crypts such as empty shells or structural voids within bioclasts (2) crypts resulting from the complete encrustation of adjacent bioclasts by Lithocodium itself and (3) syndepositionally created crypts, e. g., boreholes produced by lithophagid bivalves. In these cases, Lithocodium developed a poorly calcified structure of large cells with thin microcrystalline walls indicating a high degree of variability (phenotypic plasticity). This cryptic growth stage is interpreted as an adaption to the poorly illuminated crypts (photoadaption) in order to maximize light capture for photosynthesis. The Lower Cretaceous Lithocodium is therefore not per se a cryptoendolithic microorganism, but may show adaptation to develop and survive also in these already existing or newly created niches. © 2011 Springer-Verlag. Source

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