87 research outputs found
Recent progress in study on calcareous algae and algal sediments
No full textThe International Fossil Algae Association (IFAA), an international group of scientists who are interested in any aspect of fossil and living algae, organizes an international symposium every 4 years. Okinawa was selected to host the 11th International Symposium on Fossil Algae (Figure 1) because of great contributions to the study of calcareous algae by Japanese scientists such as Ryuji Endo, Wataru Ishijima, and Kenji Konishi (Iryu, 2004) and easy accessibility to modern and Pleistocene coral reefs for which many sedimentological and paleontological studies have been performed for more than 100 years (e.g. Iryu et al., 2006). The Symposium was held on September 14–18, 2015 with the support of the Geological Society of Japan and the Palaeontological Society of Japan. A total of 13 scientists from five countries attended the symposium. Pre-symposium field excursions (September 14–15) visited modern dasycladacean meadows (Figure 2) and Pleistocene carbonate deposits on Okinawa-jima, Central Ryukyus and coral reefs off Kerama Islands. The next 2 days (September 16–17) were devoted for the scientific sessions at the University of the Ryukyus. A special session was organized to discuss “Morphology versus molecular evidence in determining algal taxonomy and phylogeny.” A post-symposium excursion was conducted on September 18. We visited the Shuri Castle and then observed Pleistocene carbonate successions on southern Okinawa-jima. Although the number of participants was limited, there were prolonged discussions for every presentation. This thematic section collects recent studies on calcareous algae and algal sediments by IFAA members. Five papers are assembled here, covering Devonian to modern materials from Europe, Africa, and Japan
Re-description of Ishijima?s types of coralline algal species (Corallinales, Rhodophyta)
No full textRe-description of some Ishijima's type collections regading fossil coralline red algal species (Corallinales, Rhodophyta)
Re-assessment of the type collections of corallinalean species (Corallinales, Rhodophyta) described by W. Ishijima (1942–1978).
No full textMany species of fossil coralline algae have been separated on the basis of only a few characters with slight or doubtful taxonomic significance. The analysis of the type material of the fossil coralline algal species is, therefore, needed in order to assess the taxonomic status and circumscription of these taxa. Wataru Ishijima has been one of the most prolific Japanese palaeontologists who worked on fossil calcareous algae from the western Pacific region. Ishijima described a large number of new taxa of fossil calcareous algae mostly belonging to the Corallinales from Eocene to Pleistocene sedimentary successions. An analysis of some Ishijima's types of Corallinales (Rhodophyta) described from 1942 to 1960, currently housed in the Institute of Geology and Paleontology, Graduate School of Science, Tohoku University, Sendai (Japan), is presented. For fourteen taxa changes were made to previously published statements of typification. Re-examination of the types from a modern perspective of coralline algal taxonomy shows that Hydrolithon taishakuensis (Ishijima) comb. nov (= Lithothamnium taishakuensis), Sporolithon kobamazimensis (Ishijima) comb. nov. (= Archaeolithothamnium kobamazimensis), Sporolithon kuboiensis (Ishijima) comb. nov. (= Archaeolithothamnium kuboiensis) and Sporolithon taiwanensis (Ishijima) comb. nov. (= Archaeolithothamnium taiwanensis) showed significant features justifying their use as species names in coralline algal taxonomy. No diagnostic characters occur in two types (L. nishiwadai, L. otsukiensis) and therefore the taxonomic disposition of these taxa remains unknown. Lithophyllum quadratum Ishijima is a heterotypic synonym of Lithophyllum incrustans Philippi. Lithoporella crassa Ishijima and Lithoporella hayasakai Ishijima are considered heterotypic synonyms of Lithophyllum prototypum (Foslie) Foslie, while Porolithon hanzawai Ishijima is a heterotypic synonym of Hydrolithon onkodes (Heydrich) Penrose and Woelkerling. Mesophyllum arakuraensis Ishijima is co-specific and has nomenclatural priority over M. contii Ishijima. However M. arakuraensis and M. contii do not show available evidence whether either might belong to Synarthrophyton instead of Mesophyllum. Lithothamnium ishizuchiensis Ishijima and L. kasedaensis Ishijima have no diagnostic features that can be used to ally them to any particular genus or species of Melobesioideae
Hydrolithon braganum sp. nov. (Corallinaceae, Rhodophyta), the first known exclusively fossil semi-endophytic coralline red alga
No full textHydrolithon braganum sp. nov., the first known exclusively fossil semi-endophytic species of Corallinaceae (Corallinales, Corallinophycidae, Rhodophyta), is based on material from IODP Expedition 310 cores of Last deglacial age (c. 20,000 – 10,000 years BP) from reef terraces around Tahiti, French Polynesia. A detailed morphological-anatomical account is provided, and the taxonomic position of the new species at generic and subfamily levels is considered in relation to recent molecular studies and consequent proposals for changes to the concepts of the subfamily Mastophoroideae and the genus Hydrolithon. Evidence is presented to show that the morphological-anatomical criteria proposed in recent molecular-based studies are untenable for circumscribing the subfamily Mastophoroideae and for separating genera called Hydrolithon and Porolithon. Both the Mastophoroideae and Hydrolithon are best recognized as polyphyletic at present. It is not essential to superimpose a morphological-anatomical based classification system on a set of lineages inferred from analyses of molecular sequence data sets that are based only on genes not known to control any of the morphological-anatomical characters currently used to delimit subfamilies or genera, especially when this results in proposals that do not account for all included taxa and are, to varying extents, not in accord with the International Code of Botanical Nomenclature. An alternative strategy is to direct molecular systematic research more towards discovering which genes are responsible for morphological-anatomical characters used to delimit taxa of coralline red algae and then to use data from those genes along with SSU, LSU, psbA, and COI data in analyses aimed at elucidating monophyletic lineages and producing classification systems in which all included taxa are accounted for, and given valid taxonomic names, and assigned to valid taxonomic ranks that are in accord with the ICBN
REASSESSMENT OF "BOUEINA" PACIFICA ISHIJIMA, 1978 (ORBITOLININAE, FORAMINIFERIDA), FORMERLY CONSIDERED A GREEN HALIMEDACEAN ALGA
No full textBoueina pacifica Ishijima, 1978, found in Aptian shallow-water carbonates from Seberuang (Indonesia), was originally ascribed to the calcareous halimedacean algae (Chlorophyta). However, during a taxonomic revision of Ishijima's types of Corallinales (Rhodophyta) described from 1954 to 1978, the type specimens of Boueina pacifica Ishijima 1978 ‹currently housed at the Geology and Paleontology Department, National Museum of Nature and Science, Tokyo (Japan), have been identified as an orbitolinid foraminifer. The types have a microgranular shell texture with clearly distinguishable exoskeletal and endoskeletal shell structures diagnostic of the larger foraminiferal subfamily Orbitolininae. Unfortunately, "Boueina" pacifica Ishijima has no diagnostic features that can be used to ally it to any particular genus or species of the orbitolinids
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
Quando e dove comparsero le specie di alghe calcaree che oggi popolano gli oceani? Una storia di una lunga migrazione durata 27 milioni di anni.
No full textPaleobiogeografia delle specie del gruppo di Lithophyllum pustulatum
LE PRIME ALGHE ROSSE CORALLINACEE SEMI-ENDOFITE FOSSILI: RICERCHE DELL’IODP A TAHITI, POLINESIA FRANCESE
No full textRECENT 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
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