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Wyszukujesz frazę "Viola, R." wg kryterium: Autor


Wyświetlanie 1-2 z 2
Tytuł:
Fractal analysis of ostracod shell variability: A comparison with geometric and classic morphometrics
Autorzy:
Aiello, G
Barattolo, F.
Barra, D.
Fiorito, G.
Mazzarella, A.
Raia, P.
Viola, R.
Powiązania:
https://bibliotekanauki.pl/articles/22918.pdf
Data publikacji:
2007
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
fractal analysis
variability
statistical method
systematics
Krithe compressa
ostracod
shell
Ostracoda
morphometry
morphological variability
Krithe iniqua
paleontology
Opis:
Two statistical methods, fractal geometry and geometric morphometrics, are tested for their applicability to ostracod systematics. For this comparison, two morphologically similar ostracod species (Krithe compressa and Krithe iniqua) whose genus−level systematics is still incompletely resolved, are selected. Twenty−nine right valves of each species were collected from the upper Pliocene samples at the Monte San Nicola section in southern Italy. Statistical analyses (MANOVA on morphometric shape variables, and D values) were utilized to test if geometric morphometrics and fractal analysis are appropriate into discriminating between the two species. Both methods succeeded in distinguishing the species statistically. The fractal analysis of the two ostracod species shows D values centered on 1.31±0.02 for Krithe iniqua and on 1.40±0.02 for Krithe compressa. Geometric morphometric analysis indicates significant differences between the two species and allows studying intra−populational variability as well as. The most variable traits indicated by geometric morphometrics are vestibular area and posterior outline of the shell, indicating that these traits are the most relevant for the systematics of the species analyzed. Both fractal geometry and geometric morphometrics provide a measure of population variability. Fractal analysis has the advantage of being free from any subjectivity in the selection of characters and could be most appropriate to use for analysis of complex ornamentation for systematic purposes. However, a possible advantage of geometric morphometrics over fractal analysis is its ability to indicate where statistically significant variations in shape occur on the shell.
Źródło:
Acta Palaeontologica Polonica; 2007, 52, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New serpulid polychaetes from the Permian of western Sicily
Autorzy:
Sanfilippo, R.
Rosso, A.
Reitano, A.
Viola, A.
Insacco, G.
Powiązania:
https://bibliotekanauki.pl/articles/22496.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Opis:
Two new tubeworms, “Serpula” calannai sp. nov. and “Serpula” prisca sp. nov. are described from the Permian limestone of the Sosio Valley, western Sicily. Both species possess large tubes with long free anterior portions circular in cross-section. All morphological characters, such as tube shape and ornamentation, as well as inner structure of the wall, even if barely visible due to diagenesis, are still preserved. These two new species increase the previously known diversity of the Permian serpulid community, which flourished at the shelf edge of the western sector of the Palaeotethys and disappeared thereafter. The likely Wordian age of these serpulids, and their presumed absence in younger rocks up to the Middle–Late Triassic, suggests reduction, or even extinction, of these reef-related serpulid taxa during the end-Guadalupian biotic crisis, before the end-Permian extinction.
Źródło:
Acta Palaeontologica Polonica; 2018, 63, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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