Results 151 to 160 of about 696 (179)
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XV.—The Paired Fins of Placoderms
Transactions of the Royal Society of Edinburgh, 1947Within 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, 2009AbstractIntraspecies 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, 2014Extant 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 +4 more
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TERMINOLOGY OF PALEOZOIC PLACODERM FISHES (ANTIARCHI) EXOSKELETAL ELEMENTS
THE LIFE OF THE EARTH, 2021The terminology and morphology of plates of the posterior part of the antiarch head shield (Placodermi, Antiarchi) are discussed. The terms «zatilochnaya» and «bokovaya (kraevaya) zatilochnaya» was previously accepted in antiarch skulls and are suggested for use in Russian-language literature.
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Histologic Studies of Ostracoderms, Placoderms and Fossil Elasmobranchs
Zoologica Scripta, 1980An 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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The first placoderm fish from the Lower Devonian of Poland
Journal of Vertebrate Paleontology, 2015Fossils remains of placoderms are so characteristic for the Lower Devonian deposits in the Holy Cross Mountains, central Poland (Gurich, 1896), that these rocks are colloquially named the ‘Placoder...
Piotr Szrek +2 more
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Dynamics of placoderm distribution in the Prague Basin (Czech Republic)
GFF, 2014The 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
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Ventral Thoracic Neuromast Lines of Placoderm Fishes
Nature, 1965IN the past forty years, following Stenso's1 pioneer work on the arthrodire Macropetalichthys, much information has come to light in support of the view that the Palaeozoic placoderms and the still surviving elasmo-branchs and holocephalians are more closely related to each other than to any other group of fishes2.
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Placoderm fishes: diversity through time
1991Abstract The placoderms, with 250 genera, constitute a small but much diversified group of bony fishes. They are sometimes classified as stem-group osteichthyans and, together with the acanthodians, are the earliest true jawed fishes. They are found in the mid-Silurian, but flourished in the Devonian reaching their greatest diversity in ...
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Placoderm branchial and hypobranchial muscles and origins in jawed vertebrates
Journal of Vertebrate Paleontology, 2003Abstract Muscle morphology in the Placodermi can be inferred by comparison to extant gnathostomes (Chondrichthyes (Actinopterygii + Sarcopterygii)). Examination of the chondrichthyan hypobranchial musculature suggested a comparable musculature for placoderms, including the coracomandibularis and coracohyoideus, acting separately to depress the mandible
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