Search results for "7(60)"
showing 10 items of 1678 documents
Early Jurassic (Sinemurian to basal Toarcian) ammonites of the Brescian Prealps (Southern Alps, Italy).
2017
This work provides a more precise up-to-date biostratigraphical framework of the Early Jurassic ammonite succession of the Brescian Prealps with more than seventy taxa for the Sinemurian, Pliensbachian and basal Toarcian corresponding to a about 30 horizons or faunal assemblages rather well correlable with the NW European standard zonation. These results are supported with already published data, new data from recent field investigations, revised contributions of different authors and with the study of the historical collection of the Museum of Natural Sciences of Brescia (Northern Italy). The biohorizons are referred to the Lower Jurassic carbonate series of the Brescian Prealps, cropping …
Reference curves for pediatric endocrinology: leveraging biomarker z-scores for clinical classifications
2022
Abstract Context Hormone reference intervals in pediatric endocrinology are traditionally partitioned by age and lack the framework for benchmarking individual blood test results as normalized z-scores and plotting sequential measurements onto a chart. Reference curve modeling is applicable to endocrine variables and represents a standardized method to account for variation with gender and age. Objective We aimed to establish gender-specific biomarker reference curves for clinical use and benchmark associations between hormones, pubertal phenotype, and body mass index (BMI). Methods Using cross-sectional population sample data from 2139 healthy Norwegian children and adolescents, we analyze…
Preparation protocols for SEM visualization of charred fossil plants: the case of Weichselia reticulata pinnule anatomy
2021
The cosmopolite Mesozoic fern Weichselia reticulata presents many peculiarities in the anatomy of its stem as well as in the architecture of its leaves. Previous analyses of the ultrastructure of their pinnule laminas provided some insight on xeromorphic traits. In this work new protocols for the preparation of charred compression foliage specimens embedded in a limestone matrix for their observation under SEM are presented, which enhance the observation of different plant tissues. The preparation with HCl allows for the visualization of the whole lamina, from the upper to the lower epidermis, which had not been done to date. Additionally, collodion, latex, or wax coverings of the fossils b…
David Malcolm Raup (1933-2015) at the starting point of a new paradigm for Palaeontology
2020
This is a tribute to the late David Malcolm Raup, one of the major palaeontologists of the second half of the 20 th century. In addition, it is a critical review of his outstanding contributions, mainly in the field of theoretical palaeontology: quantitative modelling, the introduction of probabilistic methods in palaeontology, as well as his great imagination to use techniques from other fields, such as insurance actuary. After a general outline of his youth, I present a general depiction of the main topics of his research as a palaeobiologist: morphology, the structure of the fossil record, evolution, and extinction. He covered areas ranging from the theoretical morphology of coiled shell…
Has palaeontology answers for some current environmental problems?
2021
History as an irreversible process has no role from a uniformitarian point of view in geology and palaeobiology. Contingency is another trait of history and particle palaeontology has its foundation on such principles. However, new approaches in physics and the theory of systems point out the need to consider a time arrow. Moreover, chance and necessity are interwoven in synergetics and self-organization theory and there may be some possibility of prediction. The global biota has a history resulting from a process of self-organization. A rich fossil record was produced during the Phanerozoic times and this fossil record shows us how life overcame several important crisis. A clear understand…
The negligence and lazy of the Administration: the greatest danger to the conservation of the unique lagerstätte sites
2019
An example is given of one of the most important sites in the Spanish fossil record, such as the almost a hundred moulds of ancient jellyfish of hydrozoan Medusozoa, Cnidaria, exceptionally preserved in an arkosic greywacke bedding plane of the Corduban/Terreneuvian Epoch (lowermost Cambrian) in the municipal district of Constantina (Seville). In spite of its scientific-patrimonial importance and the fact that it has been brought to the attention of the Andalusian autonomous administration for more than twenty-five years, it has still not been the object of an adequate legal protection figure. This lack of interest or bureaucratic slowness is causing an irreparable loss in many of its eleme…
TESTING SIMILARITY COEFFICIENTS FOR ANALYSIS OF THE FOSSIL RECORD USING CLUSTERING METHODS: THE PALAEOZOIC FLORA AS A STUDY CASE
2020
This paper reports a global methodological approach based on the similarity and clustering methods of the Palaeozoic plant fossil record using a comparative approach between two similarity measures: the Jacard and Raup-Crick Coefficients. The results show that although the Raup-Crick Coefficients clearly have the potential for providing more robust results, the consequences of the extinction processes are better reflected in the similarity analysis based on the Jaccard Coefficients. On the other hand, the cluster analysis based on UPGMA algorithm shows four robust clusters and reveals new evidence for the singularity of Mississippian flora. Finally, the results obtained reveal that similari…
The trace fossil gyrochorte: ethology and paleoecology
2021
Specimens of the trace fossil Gyrochorte from the Ordovician, Jurassic and Cretaceous of Utah, and the Pliocene of Spain are described. These occurrences expand the stratigraphic range of the ichnogenus, and allow for a reexamination of this paleoenvironmentally sensitive and puzzling trace fossil. The recognition of the penetrative characteristic of the trace is essential for a correct identification, as some trace fossils have been erroneously ascribed to Gyrochorte in the past. The producer must have been a detritus-feeding worm-like animal, probably an annelid, that created a bilobed, vertically penetrating and sometimes plaited meandering trace. Gyrochorte typically occurs in sandy f…
Lower Bashkirian fusulinoideans from the upper part of the Tagnana Formation (Carboniferous, NW Algeria)
2021
The upper member of the Tagnana Formation of the Djebel Bechar Group (informally the Tagnana-3 or Tagnana Ill member) yielded fusulinoideans and other related foraminifera of the genera Pseudoendothyra (rare), Pseudostajfella (Semistaffella) (rare), Millerella, Pseudonovel/a, Plectostaffella, Eostaffella and Mediocris. The presence of Eostaffellina (rare) and Endostaffella is doubtful. The difference between Millerella and Eostaffella cannot be adequately defined by evolute versus involute coiling. Pseudonovella Kireeva, 1949 is redefined to include Seminovella Rauzer-Chernousova, 1951. The foraminifera are from two samples, one from close to the top and the other from near the base of the …
Book Review. The Pleistocene of Untermassfeld near Meiningen (Thüringen, Germany).
2020
Around one million years ago (late Early Pleistocene), a major faunal turnover occurred in Europe, linked to the onset of increased climatic instability: the transition between Villafranchian and Galerian faunas. Few palaeontological sites in Europe documents this biological event, highlighting over all of them the site of Untermassfeld, near Meiningen (Thuringia, Germany), which provided an amazing fossil record, either in abundance, diversity, and good preservation.Previous results of the interdisciplinary research developed on Untermassfeld were published in three volumes of the monograph series of the Romisch-Germanischen Zentralmuseums, Mainz, released in 1997 and 2001, as well as in a…