scholarly journals New data on internal morphology of exceptionally preserved Nannirhynchia pygmaea (Morris, 1847) from the Lusitanian Basin (Brachiopoda, Early Jurassic, Portugal)

Fossil Record ◽  
2012 ◽  
Vol 15 (2) ◽  
pp. 77-83 ◽  
Author(s):  
M. Schemm-Gregory ◽  
M. H. Henriques
Keyword(s):  
Three Dimensional ◽  
Early Jurassic ◽  
Shell Morphology ◽  
Serial Sections ◽  
Precise Description ◽  
Oceanic Anoxic Event ◽  
Internal Morphology ◽  
Anoxic Event ◽  
Dimensional Reconstruction ◽  
Lusitanian Basin

Pyritized internal moulds of articulated shells of the Early Jurassic brachiopod taxon <i>Nannirhynchia pygmaea</i> were found in beds closely below the early Toarcian oceanic anoxic event in the <i>Polymorphum</i> Zone in Portugal. The material allows a detailed study of the outline of the muscle fields, the length and direction of the crura, and the orientation of the cardinalia, which are hitherto undescribed. Three-dimensional reconstructions of articulated shells of <i>N. pygmaea</i> occurring in a single horizon were produced to show the orientation and length of arcuiform crura. The preservation of internal moulds together with the three-dimensional reconstruction of the internal shell morphology allow a more precise description of the internal morphology of this taxon than it is possible with articulated shells and serial sections. <br><br> doi:<a href="http://dx.doi.org/10.1002/mmng.201200005" target="_blank">10.1002/mmng.201200005</a>

A new Givetian athyridid species from northwest Africa discovered by three-dimensional reconstruction of shell morphology of internal molds

2014 ◽  
Vol 88 (4) ◽  
pp. 708-718 ◽  
Author(s):  
Mena Schemm-Gregory
Keyword(s):  
New Species ◽  
Three Dimensional ◽  
Shell Morphology ◽  
Serial Sections ◽  
Three Dimensional Reconstruction ◽  
Ct Scanner ◽  
Faunal Assemblage ◽  
Northwest Africa ◽  
Dimensional Reconstruction ◽  
A New Species

A new method of analyzing the internal shell morphology (including the complete brachidium of internal molds) of articulated brachiopod shells through the use of serial sections and digital three-dimensional reconstruction is presented. The method introduced is essential for the study of internal shell structures such as brachidia, or cardinalia, if computed tomography (CT) is not suitable or if a CT scanner is not available. A new species ofAthyrisfrom Givetian beds of Northwest Africa was selected to exemplify this method. To compare this species with figured serial sections in the literature, two-dimensional drawings of grinding surfaces are provided.Athyris africanan. sp. is only preserved as internal molds of articulated specimens. The new species is included in the evolutionary lineage of the group aroundAthyris concentrica. The faunal assemblage ofA. africanan. sp. shows affinities to Western European and North American brachiopod faunas.

scholarly journals The palynological response to the Toarcian Oceanic Anoxic Event (Early Jurassic) at Peniche, Lusitanian Basin, western Portugal

2017 ◽  
Vol 137 ◽  
pp. 46-63 ◽  
Author(s):  
Vânia F. Correia ◽  
James B. Riding ◽  
Luís V. Duarte ◽  
Paulo Fernandes ◽  
Zélia Pereira
Keyword(s):  
Early Jurassic ◽  
Oceanic Anoxic Event ◽  
Anoxic Event ◽  
Lusitanian Basin

scholarly journals The effects of the Jenkyns Event on the radiation of Early Jurassic dinoflagellate cysts

2021 ◽  
pp. SP514-2020-255
Author(s):  
Vânia F. Correia ◽  
James B. Riding ◽  
Luís V. Duarte ◽  
Paulo Fernandes ◽  
Zélia Pereira
Keyword(s):  
Species Richness ◽  
New Species ◽  
Lower Jurassic ◽  
Early Jurassic ◽  
Dinoflagellate Cysts ◽  
Oceanic Anoxic Event ◽  
Anoxic Event ◽  
Northern Regions ◽  
Prolonged Recovery ◽  
Lusitanian Basin

AbstractThis contribution is an overview of the Early Jurassic dinoflagellate cysts of the Lusitanian Basin in Portugal, with particular emphasis on the effects of the Jenkyns Event (Toarcian Oceanic Anoxic Event - T-OAE) on the evolution of this planktonic group. We review and discuss data from 214 samples from six Lower Jurassic successions (upper Sinemurian-upper Toarcian) in the Lusitanian Basin. The late Pliensbachian radiation of dinoflagellate cysts was well recognised in this basin. The pre-Jenkyns Event interval is highly productive, with maximum abundance and species richness values. However, this palaeoenvironmental perturbation severely affected the evolution of this group for the remainder of the Early Jurassic. The prolonged recovery of the dinoflagellates in the Toarcian following the Jenkyns Event is not typical of the northern regions (Arctic and Boreal realms), where new species began to evolve earlier compared with southern European basins.

scholarly journals Evidence for major environmental perturbation prior to and during the Toarcian (Early Jurassic) oceanic anoxic event from the Lusitanian Basin, Portugal

2008 ◽  
Vol 23 (1) ◽  
pp. n/a-n/a ◽  
Author(s):  
Guillaume Suan ◽  
Emanuela Mattioli ◽  
Bernard Pittet ◽  
Samuel Mailliot ◽  
Christophe Lécuyer
Keyword(s):  
Early Jurassic ◽  
Oceanic Anoxic Event ◽  
Environmental Perturbation ◽  
Anoxic Event ◽  
Lusitanian Basin

Three-Dimensional Reconstruction Using Stereo Pairs from Serial Thick Sections

1977 ◽  
Vol 35 ◽  
pp. 562-563
Author(s):  
Robert Glaeser ◽  
Thomas Bauer ◽  
David Grano
Keyword(s):  
Three Dimensional ◽  
Dimensional Structure ◽  
Serial Sections ◽  
Thin Sections ◽  
3 Dimensional ◽  
Transmission Electron ◽  
Freeze Dried ◽  
Dimensional Reconstruction ◽  
Stereo Imagery ◽  
Whole Mounts

In transmission electron microscopy, the 3-dimensional structure of an object is usually obtained in one of two ways. For objects which can be included in one specimen, as for example with elements included in freeze- dried whole mounts and examined with a high voltage microscope, stereo pairs can be obtained which exhibit the 3-D structure of the element. For objects which can not be included in one specimen, the 3-D shape is obtained by reconstruction from serial sections. However, without stereo imagery, only detail which remains constant within the thickness of the section can be used in the reconstruction; consequently, the choice is between a low resolution reconstruction using a few thick sections and a better resolution reconstruction using many thin sections, generally a tedious chore. This paper describes an approach to 3-D reconstruction which uses stereo images of serial thick sections to reconstruct an object including detail which changes within the depth of an individual thick section.

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