10 resultados para Supporting characters

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Suporting Information 1; Herbarium Corallina officinalis samples of the Natural History Museum (BM) analysed for the present study. Where the same NHM barcodes are provided for more than one sample, multiple samples were present under the same barcode in the herbarium. (-) indicates samples were not barcoded in the NHM (BM) system.

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Marenzelleria bastropi, a new species of Spionidae (Polychaeta) from the brackish water Currituck Sound, North Carolina, is described. The new species is characterized by the great number of chaetigers between the first neuro- and notopodial hooded hooks, the extension of the nuchal organ up to the end of chaetiger 2/middle of chaetiger 3 and the presence of about 60-90 branchiate chaetigers. Marenzelleria bastropi sp. nov. is closely related to M. neglecta (Sikorski and Bick, 2004) and Marenzelleria viridis (Verrill, 1873). Marenzelleria wireni Augener, 1913 is described here for the first time from western Spitsbergen. Adult specimens are investigated and compared with specimens from other areas of distribution. A key for subadult and adult specimens of all Marenzelleria species is provided.

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The data base for this study is represented by essentially nonevaporitic Messinian sediments recovered at ODP Sites 654, 653, 652, and 656 along the eastern Sardinian margin, and of the overlying early Pliocene oozes. Grain-size distribution, carbonate content, and microscopic observation of the sand size fractions were investigated. Messinian paleoenvironments, documented in the western Tyrrhenian Sea (ODP Sites 654 and 653), provide additional evidence supporting the deep basin desiccation model. A sharp lithologic contrast between early Pliocene pelagic oozes and latest Messinian conformable gypsiferous silts supports this model. The "lago-mare" biofacies was only occasionally observed in the shallowest site and is limited to the topmost part of the Messinian. Sites 652 and 656, lying in the deeper part of the Tyrrhenian and located on the downthrown side of an important eastward dipping fault system known as "Faglia centrale" are characterized by terrigenous sedimentation, with partly recycled minor evaporites. Of special interest is Site 652, where the thickness of the (probable) Messinian is 530 m. Sedimentary characters indicate a permanently subaqueous but nonmarine environment, with turbidites accumulating in a rapidly subsiding basin. According to the model proposed, this basin was fed by continental waters during times of maximum evaporitic draw-down, with temporary marine incursions from the west or southwest when the water level was higher. A basement ridge separated the evaporating pond from this endoreic lake located on the opposite (eastern) margin of the Tyrrhenian Basin, which was then limited to its western part. Post-Messinian reactivation of the "Faglia centrale" is necessary to account for the inversion of the relief.

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Refractive index and chemical composition were determined for glass shards contained in more than 100 tephra layers in DSDP Leg 58 sediment cores collected in the Shikoku Basin, North Philippine Sea. The refractive index is consistent with chemical composition. Refractive index and total iron show a linear relationship. Tephra in Pleistocene and Pliocene sediments is mostly rhyolitic and dacitic (non-alkali), whereas tephra in the Miocene shows wide composition variations in the eastern part of the basin. Basaltic tephra is recognized in Miocene sediments at Sites 443 and 444, but not at Site 442, west of the other two sites. This indicates that the basaltic tephra came from eruption relatively close to those drill sites (perhaps the Kinan Seamounts and the Shichito-Iwo Jima volcanic arc), although the exact source has not been identified.

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The file here provided, is the list of all characters that have been used in cladistic analysis on ammonoids published so far. It constitutes the base of a study which investigates practices in characters establishment. Find here after the abstract of the article that is associated to this file. Cladistics appears as one of the most useful method to reconstruct phylogeny of fossil taxa. However, ammonoids workers tend to sulk this method. The capital step of cladistic analysis is the recognition of homology hypothesis as clue to reconstruct monophyletic clades based on the sharing of derived traits. Previous authors have suggested that coding schemes are usually direct transcription of original taxa description. However, establishing a list of characters (i.e. a matrix taxa /characters) is a very different work compared to a compilation of diagnoses. How morphology is coded in ammonoids? How coding schemes are influenced by traditional descriptions / characters? Here, we review all cladistic analyses of ammonoids published in the literature to compare characters and the way authors have dealt with the treatment of continuous characters, polymorphism and ontogeny. Several barriers are usually invoked to justify that cladistics cannot be applied to reconstruct ammonoids phylogenies. We show that an appropriate use of improvements both on ammonoids' knowledge and cladistics methodology may overcome limitations usually invoked to perform cladistic analysis on ammonoids.