Exceptionally preserved Mickwitzia from the Indian Springs Lagerstätte (Cambrian Stage 3), Nevada

2015 ◽  
Vol 89 (6) ◽  
pp. 933-955 ◽  
Author(s):  
Aodhán D. Butler ◽  
Michael Streng ◽  
Lars E. Holmer ◽  
Loren E. Babcock
Keyword(s):  
Microscopic Analysis ◽  
Phylogenetic Position ◽  
Generic Diagnosis ◽  
Electron Microscopic ◽  
Small Shelly Fossils ◽  
Stem Group ◽  
Scanning Electron Microscopic ◽  
Close Relationship ◽  
Scanning Electron Microscopic Analysis ◽  
Insight Into

AbstractExceptionally preserved specimens of the Cambrian stem-group brachiopod Mickwitzia occidens Walcott, 1908 are described in detail from the Indian Springs Lagerstätte in Nevada, USA. Shell structure and preserved mantle setae from these specimens reveal a variable diagenetic (taphonomic) history and provide insight into the phylogenetic position of mickwitziids. Morphologic and morphometric comparison to M. monilifera (Linnarsson, 1869) from Sweden and M. muralensis Walcott, 1913 from British Columbia, Canada reveals clear species-level distinctions. Scanning electron microscopic analysis allows revision of the generic diagnosis. The Mickwitzia shell is characterized by the presence of inwardly pointing phosphatic cones and tangential setae-bearing tubes. The inwardly pointing cone structures are not consistent with setal bearing structures as previously thought, but rather represent endopunctae-like structures. Acrotretid-like shell structures and shell-penetrating setae in M. occidens strengthen the previously proposed close relationship between stem-group brachiopods and tommotiids, a group of small shelly fossils.

scholarly journals Mechanistic Study on Gold-Like Luster Development of Solution-Cast Oligo(3-methoxythiophene) Film

Coatings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 861
Author(s):  
Minako Kubo ◽  
Minako Tachiki ◽  
Terumasa Mitogawa ◽  
Kota Saito ◽  
Ryota Saito ◽  
...  
Keyword(s):  
Microscopic Analysis ◽  
Mechanistic Study ◽  
Free Electrons ◽  
Coating Films ◽  
Electron Microscopic ◽  
Regular Structures ◽  
Scanning Electron Microscopic ◽  
Solution Cast ◽  
Scanning Electron Microscopic Analysis ◽  
Reflectance Measurements

Solution-cast coating films of perchlorate-doped oligo(3-methoxythiophene) exhibited a gold-like luster similar to that of metallic gold despite the involvement of no metals. However, the development mechanism of the luster remains ambiguous. To understand the mechanism, we performed scanning electron microscopic analysis, variable-angle spectral reflectance measurements, and ellipsometry measurements on ClO4−-doped oligo(3-methoxythiophene) cast film with a gold-like luster. The results revealed that the lustrous color of the film was not induced by the submicron-sized regular structures (structural color), nor by the high-density free electrons (reflective response based on Drude model), but by the large optical constants (refractive index and extinction coefficient) of the film, as speculated previously.

Wear and microwear on the teeth of a moose (Alces alces) population in Manitoba, Canada

1986 ◽  
Vol 64 (11) ◽  
pp. 2467-2479 ◽  
Author(s):  
William G. Young ◽  
Therese M. Marty
Keyword(s):  
Tooth Loss ◽  
Microscopic Analysis ◽  
Tooth Wear ◽  
Incisor Tooth ◽  
Electron Microscopic ◽  
Tooth Structure ◽  
Microwear Analysis ◽  
Anterior Teeth ◽  
Scanning Electron Microscopic ◽  
Scanning Electron Microscopic Analysis

A group of wild moose from Manitoba, Canada, were documented as having excessive tooth wear. Replicas of one incisor tooth were collected from 16 individuals and from 19 controls for comparison by volumetric and scanning electron microscopic analysis. All animals were aged from tooth cementum lines. Tooth replicas were cast from silicone rubber impressions in epoxy resin and sputter coated with gold. Tooth wear with age was compared statistically by measuring crown height, percent tooth loss, interfacet distance, and facet area on the incisors. The unique pattern of wear on the anterior teeth of affected moose was described. In affected animals, crown heights were significantly reduced and percent tooth loss was excessive. Microwear analysis found that an abrasive agent, acting predominantly in a lingual to labial direction, had been responsible for loss of enamel and dentine incisally and interproximally, and on the facial and lingual surfaces to a lesser extent. Interdental facets became involved by vertical abrasion. Control teeth showed fewer but coarser scratches and only approached the pattern of wear found in affected moose in a few individuals in old age. The loss of tooth structure would lead to diminished cropping efficiency and damage to the periodontium.

Scanning Electron Microscopic Analysis of Fossil Bone (Mosasaurs) from Marine Deposits of the Upper Cretaceous of North America

1999 ◽  
Vol 5 (S2) ◽  
pp. 328-329
Author(s):  
M. Amy Sheldon
Keyword(s):  
North America ◽  
Histological Study ◽  
Microscopic Analysis ◽  
Electron Microscopic ◽  
Marine Deposits ◽  
Fossil Material ◽  
Destructive Analysis ◽  
Scanning Electron Microscopic ◽  
Scanning Electron Microscopic Analysis ◽  
Scanning Electron

Research into bone histology of fossil material is a growing area of inquiry in vertebrate paleontology. Incorporating histological study into ontogenetic investigation presents new opportunities for gaining data to better understand ontogeny, ecology, and evolution of mosasaurs. Adding scanning electron microscopy to the growing technology being applied to fossil research can only further the understanding of long extinct animals.Mosasaurs were totally marine lizards which inhabited both open ocean and epicontinental seas during the late Cretaceous (Turonian through Maestrichtian), approximately 90-65. million years ago. Mosasaurs have been collected from many areas of North America. The specimens used in this study were collected from Alabama, Kansas, South Dakota, and Texas. I have restricted the fossil material for destructive analysis to ribs and vertebrae. Ribs have not been shown to have importance in morphological analysis relating to systematics or evolution, therefore their destruction does not imped the research of others. Vertebrae were isolated on outcrop but could be identified to genus and growth stage.

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