Results 151 to 160 of about 643 (178)

Devonian Placoderm Scales from Australia

Journal of Vertebrate Paleontology, 1998
The morphology and histology of Australian placoderm scales which were found associated with dermal plates are described and compared. The specimens include the arthrodire Buchanosteus confertituberculatus from the Early Devonian (Emsian) of Buchan, Victoria, the arthrodires Goodradigbeeon australianium and Buchanosteidae gen. et sp.
Burrow C.J., Turner S.
openaire   +3 more sources

The Silurian Placoderms from Vietnam: A Reappraisal Based on the Consideration of Silurian “Maxillate Placoderms” from South China

Paleontological Journal
Philippe Janvier
exaly   +2 more sources

Placoderms (Armored Fish): Dominant Vertebrates of the Devonian Period

Annual Review of Earth and Planetary Sciences, 2010
Placoderms, the most diverse group of Devonian fishes, were globally distributed in all habitable freshwater and marine environments, like teleost fishes in the modern fauna. Their known evolutionary history (Early Silurian–Late Devonian) spanned at least 70 million years.
Gavin C Young
exaly   +3 more sources

Placoderm fishes, pharyngeal denticles, and the vertebrate dentition

Journal of Morphology, 2003
AbstractThe correlation of the origin of teeth with jaws in vertebrate history has recently been challenged with an alternative to the canonical view of teeth deriving from separate skin denticles. This alternative proposes that organized denticle whorls on the pharyngeal (gill) arches in the fossil jawless fish Loganellia are precursors to tooth ...
Johanson, Z, Smith, M M
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Further consideration of placoderm evolution

Journal of Vertebrate Paleontology, 1983
ABSTRACT The flight performances of Pteranodon ingens and Nyctosaurus gracilis from the Upper Cretaceous of Kansas were modeled using data from a Sailvane hang-glider which has an airfoil similar to that of a pterosaur. The aerodynamics of large pterosaurs were mainly dictated by three parameters: low wing loadings, wings with high aspect ratios, and ...
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XV.—The Paired Fins of Placoderms

Transactions of the Royal Society of Edinburgh, 1947
Within the last twenty years our knowledge of the structure and distribution of the armoured Placodermi (including Arthrodira, Ptyctodonta, Phyllolepida, Macropetalichthyida, Rhenanida, and Antiarcha) has increased tremendously. The writer is engaged on a morphogenetic analysis of the group, early publication of which is uncertain.
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Phenotypic plasticity, polymorphism and phylogeny within placoderms

Acta Zoologica, 2009
AbstractIntraspecies variation, polymorphism and asymmetric traits are observed within two families of Arthrodira, the Incisoscutidae and Camuropiscidae, from the Gogo Formation in northern Western Australia. Individual plates of the head and trunk shield show considerable variation between individuals.
K. Trinajstic, K. Dennis‐Bryan
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A primitive placoderm sheds light on the origin of the jawed vertebrate face

Nature, 2014
Extant vertebrates form two clades, the jawless Cyclostomata (lampreys and hagfishes) and the jawed Gnathostomata (all other vertebrates), with contrasting facial architectures. These arise during development from just a few key differences in the growth patterns of the cranial primordia: notably, the nasal sacs and hypophysis originate from a single ...
Vincent, Dupret, Sophie, Sanchez, Daniel, Goujet, Paul, Tafforeau, Per E, Ahlberg   +4 more
openaire   +2 more sources

Histologic Studies of Ostracoderms, Placoderms and Fossil Elasmobranchs

Zoologica Scripta, 1980
An account is given of the structure and growth of certain ptyctodontid tooth plates, especially those of Ctenurella gladbachensis, based on study by light microscopy and the SEM. These tooth plates consist of a framework of acellular bone tissue and an interior hard tissue referred to as pleromin.
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Dynamics of placoderm distribution in the Prague Basin (Czech Republic)

GFF, 2014
The occurrence of placoderms in the Prague Basin (Bohemian Massif; Czech Republic) shows a very unsteady distribution in space and time. The most abundant specimens are in the Lochkovian and, through decrease in the Pragian, they become rare towards the Givetian.
Valéria Vaškaninová, Petr Kraft
openaire   +1 more source