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Geosciences, Volume 2, Issue 3 (September 2012), Pages 147-177

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Research

Open AccessArticle Bythocythere solisdeus n. sp. and Cytheropteron eleonorae n. sp. (Crustacea, Ostracoda) from the Early Pleistocene Bathyal Sediments of Cape Milazzo (NE, Sicily)
Geosciences 2012, 2(3), 147-156; doi:10.3390/geosciences2030147
Received: 21 May 2012 / Revised: 19 June 2012 / Accepted: 29 June 2012 / Published: 9 July 2012
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Abstract
Two new fossil species of Ostracoda belonging to the genus Bythocythere Sars, 1866, Bythocythere solisdeus n. sp. and to the genus Cytheropteron Sars, 1866, Cytheropteron eleonorae n. sp. are described. The specimens come from the upper silty sand layers of the Globorotalia truncatulinoides
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Two new fossil species of Ostracoda belonging to the genus Bythocythere Sars, 1866, Bythocythere solisdeus n. sp. and to the genus Cytheropteron Sars, 1866, Cytheropteron eleonorae n. sp. are described. The specimens come from the upper silty sand layers of the Globorotalia truncatulinoides excelsa Zone (“Sicilian” stage), cropping out in “Cala S. Antonino” along the western side of the Cape Milazzo Peninsula (NE Sicily). Both species belong to a typical Bathyal ostracod association characterized by very low temperatures. Full article
(This article belongs to the Special Issue Paleontology and Geo/Biological Evolution)
Open AccessArticle Homology and Potential Cellular and Molecular Mechanisms for the Development of Unique Feather Morphologies in Early Birds
Geosciences 2012, 2(3), 157-177; doi:10.3390/geosciences2030157
Received: 30 July 2012 / Revised: 30 August 2012 / Accepted: 3 September 2012 / Published: 14 September 2012
Cited by 17 | PDF Full-text (8419 KB) | HTML Full-text | XML Full-text
Abstract
At least two lineages of Mesozoic birds are known to have possessed a distinct feather morphotype for which there is no neornithine (modern) equivalent. The early stepwise evolution of apparently modern feathers occurred within Maniraptora, basal to the avian transition, with asymmetrical pennaceous
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At least two lineages of Mesozoic birds are known to have possessed a distinct feather morphotype for which there is no neornithine (modern) equivalent. The early stepwise evolution of apparently modern feathers occurred within Maniraptora, basal to the avian transition, with asymmetrical pennaceous feathers suited for flight present in the most basal recognized avian, Archaeopteryx lithographica. The number of extinct primitive feather morphotypes recognized among non-avian dinosaurs continues to increase with new discoveries; some of these resemble feathers present in basal birds. As a result, feathers between phylogenetically widely separated taxa have been described as homologous. Here we examine the extinct feather morphotypes recognized within Aves and compare these structures with those found in non-avian dinosaurs. We conclude that the “rachis dominated” tail feathers of Confuciusornis sanctus and some enantiornithines are not equivalent to the “proximally ribbon-like” pennaceous feathers of the juvenile oviraptorosaur Similicaudipteryx yixianensis. Close morphological analysis of these unusual rectrices in basal birds supports the interpretation that they are modified pennaceous feathers. Because this feather morphotype is not seen in living birds, we build on current understanding of modern feather molecular morphogenesis to suggest a hypothetical molecular developmental model for the formation of the rachis dominated feathers of extinct basal birds. Full article
(This article belongs to the Special Issue Paleontology and Geo/Biological Evolution)
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