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Wyszukujesz frazę "morphometrics" wg kryterium: Temat


Wyświetlanie 1-7 z 7
Tytuł:
Geometric morphometric analysis and taxonomic revision of the Gzhelian (Late Pennsylvanian) conodont Idiognathodus simulator from North America
Autorzy:
HOGANCAMP, NICHOLAS J.
BARRICK, JAMES E.
STRAUSS, RICHARD E.
Powiązania:
https://bibliotekanauki.pl/articles/945657.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
conodonta
idiognathodus
morphometrics
pennsylvanian
gzhelian
north america
midcontinent
Opis:
A new morphometric approach was developed to study morphological variation within P1 elements commonly referred to as Idiognathodus simulator, which was selected to be the biostratigraphic marker for the base of the global Gzhelian Stage (Carboniferous). This new approach combines landmark-based geometric morphometrics with eigen analyses to analyze shape variation within P1 elements of the I. simulator group, and could be used to analyze shape variation in other morphologically similar conodont groups. Specimens analyzed were obtained from three sections of the early Gzhelian Heebner Shale of the Oread cyclothem in the North American Midcontinent region, the cyclothem from which I. simulator was originally named. This analysis shows that the I. simulator group comprises a set of at least five species with asymmetrical P1 element pairs, relatively short adcarinal ridges, and a variably developed eccentric groove. Species discrimination is based on the presence of caudal and rostral lobes, character of the adcarinal ridges, and platform shape. The species I. simulator is restricted to P1 elements with a caudal adcarinal ridge that is isolated from the caudal platform margin. Idiognathodus lateralis sp. nov. is erected to include P1 elements with a caudal adcarinal ridge that is not isolated from the caudal platform margin.
Źródło:
Acta Palaeontologica Polonica; 2016, 61, 3; 477-502
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Postcranial osteology of the first early-stage juvenile skeleton of Plateosaurus trossingensis from the Norian of Frick, Switzerland
Autorzy:
Nau, D.
Lallensack, J.N.
Bachmann, U.
Sander, P.M.
Powiązania:
https://bibliotekanauki.pl/articles/2082237.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Dinosauria
Sauropodomorpha
morphometrics
morphology
small body size
early ontogeny
Triassic
Swiss Plateau
Opis:
Owing to monospecific mass-accumulation sites in Central Europe, the early-branching sauropodomorph Plateosaurus has one of the best fossil records among dinosaurs. Despite this, early-stage juveniles have been conspicuously absent. However, such specimens are critical in assessing the ontogenetic development of this taxon, as well as the role of heterochrony in sauropodomorph evolution. A new skeleton from the Plateosaurus bonebed at the Gruhalde Quarry (Klettgau Formation, Norian) of Frick, Switzerland, nicknamed “Fabian”, represents the first substantially complete juvenile referrable to Plateosaurus. The specimen includes large portions of the cranium and vertebral column and an almost completely represented appendicular skeleton. Its juvenile ontogenetic stage is confirmed by a lack of neurocentral suture fusion in the axial skeleton. Consistent with this, the estimated total length and body mass of approximately of 2.3 m and 40 kg are considerably smaller than any previously reported specimen of the genus. Surprisingly, the postcranial morphology of the specimen is remarkably consistent with that of osteologically mature individuals, including a virtually fully developed pattern of laminae and fossae in the vertebrae. Comparisons of body proportions are complicated by varying degrees of compaction in the limb elements, but skeletal proportions mostly appear to follow isometry, with the notable exceptions of a relatively long neck, proportionately larger manus, shorter, more gracile humerus and shorter forearm in the juvenile specimen. The observed morphology suggests that adult morphology was either achieved early in ontogeny of Plateosaurus, or alternatively that developmental plasticity, which has previously been found to result in high variability of adult body size, could potentially also extend to morphological development.
Źródło:
Acta Palaeontologica Polonica; 2020, 65, 4; 679-708
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Easily-accessible digital palaeontological databases - a new perspective for the storage of palaeontological information
Autorzy:
Wolniewicz, Paweł
Powiązania:
https://bibliotekanauki.pl/articles/94271.pdf
Data publikacji:
2009
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
digitization
morphometrics
palaeoinformatics
palaeontological collection
palaeontological databases
semantic web
digitalizacja
morfometria
sieć semantyczna
Opis:
Techniques that allow to render diverse types of palaeontological data as publicly available internet resources are described. In order to develop an easily accessible digital palaeontological database, three steps should be followed: (1) digitization of the studied specimens, (2) acquisition of morphometric data, and (3) contribution of the data to open and searchable geoinformatic (palaeontological) databases. Digital data should be submitted to internet databases that allow a user to fetch various types of information from dispersed sources (semantic web services).
Źródło:
Geologos; 2009, 15, No. 3-4; 181-188
1426-8981
2080-6574
Pojawia się w:
Geologos
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A revision of Campyloprion Eastman, 1902 (Chondrichthyes, Helicoprionidae), including new occurrences from the Upper Pennsylvanian of New Mexico and Texas, USA
Autorzy:
Itano, W. M.
Lucas, S. G.
Powiązania:
https://bibliotekanauki.pl/articles/139067.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
carboniferous
permian
eugeneodontiformes
helicoprionidae
edestoidea
Chondrichthyes
geometric morphometrics
karbon
perm
ryby chrzęstnoszkieletowe
ryby chrzęstne
chrzęstniki
morfometria geometryczna
Opis:
Campyloprion Eastman, 1902 is a chondrichthyan having an arched symphyseal tooth whorl similar to that of Helicoprion Karpinsky, 1899, but less tightly coiled. The holotype of Campyloprion annectans Eastman, 1902, the type species of Campyloprion, is of unknown provenance, but is presumed to be from the Pennsylvanian of North America. Campyloprion ivanovi (Karpinsky, 1922) has been described from the Gzhelian of Russia. A partial symphyseal tooth whorl, designated as Campyloprion cf. C. ivanovi, is reported from the Missourian Tinajas Member of the Atrasado Formation of Socorro County, New Mexico, USA. Partial tooth whorls from the Virgilian Finis Shale and Jacksboro Limestone Members of the Graham Formation of northern Texas, USA, are designated as Campyloprion sp. Two partial tooth whorls from the Gzhelian of Russia that were previously referred to C. ivanovi are designated as Campyloprion cf. C. annectans. The age of Toxoprion lecontei (Dean, 1898), from Nevada, USA, is corrected from the Carboniferous to the early Permian. An alternative interpretation of the holotype of T. lecontei is presented, resulting in a reversal of its anterior-to-posterior orientation. The genera Helicoprion, Campyloprion, and Shaktauites Tchuvashov, 2001 can be distinguished by their different spiral angles.
Źródło:
Acta Geologica Polonica; 2018, 68, 3; 403-419
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ontogenetic changes in the craniomandibular skeleton of the abelisaurid dinosaur Majungasaurus crenatissimus from the Late Cretaceous of Madagascar
Autorzy:
Ratsimbaholison, N.O.
Felice, R.N.
O’Connor, P.M.
Powiązania:
https://bibliotekanauki.pl/articles/21868.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
ontogenetic change
craniomandibular skeleton
abelisaurid dinosaur
Majungasaurus crenatissimus
Dinosauria
Abelisauridae
geometric morphometrics
ontogenesis
skull
Cretaceous
Gondwana
Late Cretaceous
Madagascar
Opis:
Abelisaurid theropods were one of the most diverse groups of predatory dinosaurs in Gondwana during the Cretaceous. The group is characterized by a tall, wide skull and robust cervical region. This morphology is thought to have facilitated specialized feeding behaviors such as prolonged contact with prey. The Late Cretaceous abelisaurid Majungasaurus crenatissimus typifies this abelisaurid cranial morphotype. Recent fossil discoveries of this species include a partial growth series that allows for the first time an investigation of ontogenetic variation in cranial morphology in a representative abelisaurid. Herein we examine growth trajectories in the shape of individual cranial bones and articulated skulls of Majungasaurus using geometric morphometrics. Several major changes in skull shape were observed through ontogeny, including an increase in the height of the jugal, postorbital, and quadratojugal, an increase in the extent of the contacts between bones, and a decrease in the circumference of the orbit. The skull transitions from relatively short in the smallest individual to tall and robust in large adults, as is seen in other theropods. Such morphological change during ontogeny would likely have resulted in different biomechanical properties and feeding behaviors between small and large individuals. These findings provide a post-hatching developmental framework for understanding the evolution of the distinctive tall skull morphology seen in abelisaurids and other large-sized theropod dinosaurs.
Źródło:
Acta Palaeontologica Polonica; 2016, 61, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Taxonomic revision of the Paradoxididae Hawle and Corda, 1847 from the Miaolingian (Cambrian) of the Holy Cross Mountains, Poland: a morphometric approach to simply deformed trilobites
Autorzy:
Nowicki, Jakub
Żylińska, Anna
Powiązania:
https://bibliotekanauki.pl/articles/2024019.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
paradoxididae
miaolingian
Cambrian
Holy Cross Mountains
geometric morphometrics
simple deformation
Słowiec Hill
trylobity
miaoling
kambr
góry Świętokrzyskie
morfometria geometryczna
Słowiec
Opis:
The taxonomy of simply deformed paradoxidids from the Miaolingian (Cambrian) of Słowiec Hill, Holy Cross Mountains, Poland, is revised based on morphometric analysis. The material represents two species: Acadoparadoxides slowiecensis (Czarnocki in Orłowski, 1965) and Hydrocephalus? polonicus (Czarnocki in Orłowski, 1965). A new assemblage zone based on the combined although not precisely known ranges of these two taxa is suggested replacing the previous Paradoxides polonicus Zone of Orłowski (1975, 1988, 1992a). The Acadoparadoxides slowiecensis–Hydrocephalus? polonicus Assemblage Zone corresponds to the middle and upper part of the Wuliuan Stage (lower Miaolingian).
Źródło:
Acta Geologica Polonica; 2021, 71, 4; 371--391
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A comprehensive study of clustering a class of 2D shapes
Autorzy:
Kaliszewska, Agnieszka
Syga, Monika
Powiązania:
https://bibliotekanauki.pl/articles/2055154.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
shape representation
Procrustes distance
shape similarity
dynamic time warping
DTW
morphometrics
clustering
Kendall shape theory
archaeological pottery
reprezentacja kształtu
podobieństwo kształtu
ceramika archeologiczna
Opis:
The paper is concerned with clustering with respect to the shape and size of 2D contours that are boundaries of cross-sections of 3D objects of revolution. We propose a number of similarity measures based on combined disparate Procrustes analysis (PA) and dynamic time warping (DTW) distances. A motivation and the main application for this study comes from archaeology. The computational experiments performed refer to the clustering of archaeological pottery.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2022, 32, 1; 95--109
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-7 z 7

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