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RECENT ICHNOCOENOSIS IN DEEP WATER MACROIDS, RYUKYU ISLANDS, JAPAN
No full textMacroids provide a stable and three-dimensional habitat to which seaweeds, coralline red algae and invertebrates can attach. Some of these organisms act as borers and leave traces which are preservable in the fossil material and are potentially paleoenvironmental indicators in palaeoenvironmental analysis. Although most investigations of ichnocoenoses have focused on shallow-water settings, boring organisms such as sponges, suspension-feeding bivalves, polychaetes and annelid worms may also act in deeper fore-reef settings. We describe for the first time the ichnocoenosis of Entobia, Gastrochaenolites, Trypanites and Maeandropolydora from deep water reef settings. This ichnocoenosis, commonly so far identified only in shallow-marine rockgrounds and hardgrounds and in firm, compacted, but unlithified substrates, occurs in living macroid assemblages ranging in water depth from 61 to 105 m, southwest of Kikaijima, northern Ryukyu Islands (southern Japan). Importantly, this discovery strengthens the hypothesis that this ichnocoenosis can be utilized as a palaeoenvironmental indicator of low sedimentation rate and high turbulence rather than as a palaeobathymetric proxy
Macroid growth off Kikai-jima (Ryukyu Islands, southern Japan) and its taphonomic characterization
No full textRecent macroids from the northern Ryukyu Islands, Japan, are described in terms of growth forms, shapes, taphonomic signatures and ichnocoenoses
Typification and reassessment of seventeen species of coralline red algae (Corallinales and Sporolithales, Rhodophyta) described by W. Ishijima during 1954–1978
No full textThe type specimens of 17 species of non-geniculate coralline red algae belonging to the Corallinales and Sporolithales (Corallinophycidae, Rhodophyta) and established from 1954–1978 by Wataru Ishijima have been re-examined, focusing on characters relevant to modern coralline taxonomy. The species are from the Early Cretaceous, Eocene, Oligocene, Miocene and Pleistocene rocks of southern and central Japan, Indonesia, Malaysia, Indian Ocean, Philippines, Pakistan and Galapagos and were attributed by Ishijima to Lithothamnion (as Lithothamnium), Mesophyllum, Lithophyllum and Archaeolithothamnion (as Archaeolithothamnium). With two exceptions, all species had to be reassigned to different genera or were of uncertain generic placement within particular subfamilies, families or orders. The type specimen of Lithophyllum oboraensis is retained in Lithophyllum and the type specimen of Mesophyllum izuensis is retained in Mesophyllum. The type specimens of Lithophyllum izuensis (Ishijima) comb nov. (= Lithothamnion izuensis), Phymatolithon tokumanensis (Ishijima) comb. nov. (= Mesophyllum tokumanensis), Sporolithon borneoensis (Ishijima) comb. nov. (= Archaeolithothamnium borneoense) and Sporolithon galapagosensis (Ishijima) comb. nov. (= Archaeolithothamnion galapagosensis) possess features justifying their assignment to various genera within a particular family and subfamily. A specimen ascribed by Ishijima to Archaeolithothamnion galapagosensis (as Archaeolithothamnium) in the protologue of that species is a misidentified specimen of Sporolithon ptychoides Heydrich. The type specimens of Lithophyllum minoensis and Mesophyllum indicum belong to the Corallinaceae, subfamily Mastophoroideae but are of uncertain generic placement. The type specimens of Lithothamnion makinogoensis, Lithothamnion nodai, Lithothamnion tenuicrustatum, Mesophyllum niinoi and Mesophyllum yuyashimaensis belong to the Hapalidiaceae (Melobesioideae) but are of uncertain generic placement. The type specimens of Lithophyllum hashimotoi, Lithophyllum minae, Lithothamnion huseinii and Lithothamnion tokiensis lacked sufficient data to allow for order, family, subfamily or genus placement within the Corallinophycidae. Lectotype specimens have been designated as necessary, and relevant historical, repository, geological, morphological and other data are presented in the taxonomic accounts and concluding remarks
Recent deep-water macroid beds from southwest of Kikai-jima in the northern Ryukyu Islands, southern Japan: ecology and taphonomy
No full textRhodolith beds from the Abrolhos Bank, Brazilian platform: taphonomy, geochemistry, ecology
No full textRecent rhodoliths from the Abrolhos Bank (Brazil) are described and discussed to assess the ecological setting where they are growing
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Bathymetric distribution of ichnocoenoses from recent subtropical algal nodules off Fraser Island, eastern Australia
No full textCoralline algal nodules living on the subtropical shelf off Fraser Island, eastern Australia, fromthe inner to the uppermost outer-shelf, from28 to 117 mwater depth are pervasively bioeroded. Five ichnogenera have been identifed as nodule borers, comprising one ichnotaxon attributed to bivalves (Gastrochaenolites), one to sponges (Entobia) and three to polychaetes and barnacles (Trypanites, Maeandropolydora, Rogerella). Microtraces comparable to those produced by fungi, algae, bacteria and/or sponges are also present. Two ichnocoenoses have been recognised. The ‘shallow’ water ichnocoenosis (EGTM) occurs at 60 m and shallower depths and includes all identified ichnogenera. The ‘deep’ water ichnocoenosis (from 68 to 117 m) is characterised by Trypanites and the Trypanites/Maeandropolydora network (TM ichnocoenosis) with a generally higher boring density than in shallower nodules. Decreasing size of algal nodules and reduced thickness of the coralline thalli probably explain the decrease in diversity of ichnogenera with depth, as the larger bioeroders are excluded from the ichnoassemblages. Lower growth rates favour higher density of bioerosion in deeper algal nodules
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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