A review of freshwater species of Diphyllobothrium with redescriptions and the distribution of D. dendriticum (Nitzsch, 1824) and D. ditremum (Creplin, 1825) from North America

1987 ◽  
Vol 65 (9) ◽  
pp. 2216-2228 ◽  
Author(s):  
Karin Andersen ◽  
Hilda Lei Ching ◽  
Rolf Vik
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
British Columbia ◽  
North America ◽  
Freshwater Species ◽  
Histological Techniques ◽  
Diphyllobothrium Dendriticum ◽  
Fish Samples ◽  
Diphyllobothrium Latum ◽  
Scanning Electron

Plerocercoids of Diphyllobothrium were studied from fish samples representing eight species of salmonids from British Columbia, Wyoming, Quebec, and Maine. Adults were studied mainly from experimental infections of golden hamsters, Mesocricetus auratus (Waterhouse). Using scanning electron microscopy and histological techniques, the plerocercoids and adults were identified as Diphyllobothrium dendriticum or Diphyllobothrium ditremum. Morphological comparisons were made with European specimens of these two species and those of Diphyllobothrium latum (Linnaeus, 1758). Among the nine freshwater species reviewed, Diphyllobothrium cordiceps (Leidy, 1872), Diphyllobothrium sebago (Ward, 1910), and Diphyllobothrium ursi Rausch, 1954, are considered synonyms of Diphyllobothrium dendriticum.

scholarly journals A reexamination of Yuknessia from the Cambrian of British Columbia and Utah

2015 ◽  
Vol 89 (1) ◽  
pp. 82-95 ◽  
Author(s):  
Steven T. LoDuca ◽  
Jean-Bernard Caron ◽  
James D. Schiffbauer ◽  
Shuhai Xiao ◽  
Anthony Kramer
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
British Columbia ◽  
National Park ◽  
Red Alga ◽  
Fine Scale ◽  
Burgess Shale ◽  
Phylogenetic Affinity ◽  
New Material ◽  
Scanning Electron

AbstractTo investigate the phylogenetic affinity of Yuknessia simplex Walcott, 1919, scanning electron microscopy was applied to the Burgess Shale (Cambrian Series 3, Stage 5) type material and to new material from the Trilobite Beds (Yoho National Park) and specimens from the Cambrian of Utah. On the basis of fine-scale details observed using this approach, including banding structure interpreted as fusellae, Yuknessia Walcott, 1919 is transferred from the algae, where it resided for nearly a century, to the extant taxon Pterobranchia (Phylum Hemichordata). Considered as such, Yuknessia specimens from the Trilobite Beds and Spence Formation (Utah) are amongst the oldest known colonial pterobranchs. Two morphs regarded herein as two different species are recognized from the Trilobite Beds based on tubarium morphology. Yuknessia simplex has slender erect tubes whereas Yuknessia stephenensis n. sp., which is also known in Utah, has more robust erect tubes. The two paratypes of Y. simplex designated by Walcott (1919) are formally removed from Yuknessia and are reinterpreted respectively as an indeterminate alga and Dalyia racemata Walcott, 1919, a putative red alga.

Isoetes × marensis, a new interspecific hybrid from western Canada

1995 ◽  
Vol 73 (9) ◽  
pp. 1345-1353 ◽  
Author(s):  
Donald M. Britton ◽  
Daniel F. Brunton
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
British Columbia ◽  
Key Words ◽  
North American ◽  
Interspecific Hybrid ◽  
Western Canada ◽  
Hybrid Plants ◽  
Surface Ornamentation ◽  
Scanning Electron

A new interspecific hybrid in Isoetes, I. maritima Underw. × I. howellii Engelm., is delineated and described from the Shuswap Highlands region of British Columbia by means of cytology and scanning electron microscopy of spores. Isoetes × marensis D.M. Britton and D.F. Brunton, hyb.nov. is the name proposed for this taxon. It is triploid (3x; 2n = 33) and is believed to produce only sterile and (or) aborted spores. Hybrid plants have polymorphic spores that demonstrate size and surface ornamentation features intermediate between those of the putative parents. Three populations were examined, each growing with both of the putative parents in silt and sand among granite cobble over clay along an emergent lakeshore. Isoetes × marensis is the first described North American hybrid involving an amphibious Isoetes. It is expected to be a rare taxon owing to the restricted sympatric area of the putative parents and their tendency to occupy different habitats. Key words: Isoetes, Isoetes howellii, Isoetes maritima, hybrid, British Columbia.

scholarly journals The foregut of the Mysida (Crustacea, Peracarida) and its phylogenetic relevance

1998 ◽  
Vol 353 (1368) ◽  
pp. 559-581 ◽  
Author(s):  
Wulf Kobusch
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Histological Techniques ◽  
Ground Pattern ◽  
Neomysis Integer ◽  
Probable Function ◽  
Mesopodopsis Slabberi ◽  
Scanning Electron

The foreguts of the mysids Antarctomysis maxima , A. ohlinii , Hansenomysis antarctica , Heteromysis formosa , Mesopodopsis slabberi , Neomysis integer , Paramysis kessleri , Praunus flexuosus , and Siriella jaltensis were examined by maceration methods, histological techniques, and scanning electron microscopy. Their morphology, their connection with the midgut glands, and probable function are described and summarized. Previous stomach investigations on mysids and the results of the present study are tabulated; a list of foregut characters, common to all Mysida, is presented. The phylogenetic relevance of these characters within the Malacostraca, especially within the Peracarida, is discussed. Most features are inherited from the ground pattern of the Malacostraca or Eumalacostraca. The bulbous cardia with its dorsal fold, the armature of the lateralia, and the construction of the funnel region are apomorphies for the Mysida. The results suggest that characters of mysidan and other peracaridan foreguts might also be useful in the elucidation of the phylogeny of the Mysida and Peracarida, respectively.

Elemental Analysis of Alkalis and Dental Deposits Associated with Coca Chewing in Ecuador

2006 ◽  
Vol 17 (1) ◽  
pp. 77-89 ◽  
Author(s):  
Douglas H. Ubelaker ◽  
Karen E. Stothert
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Spectral Analysis ◽  
North America ◽  
Elemental Analysis ◽  
X Ray ◽  
Tooth Structure ◽  
Elemental Analyses ◽  
The Relationship ◽  
Scanning Electron

AbstractThe relationship between Andean coca use and dental deposits is explored through the use of scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS). Elemental analyses of samples of large dental deposits from archeologically recovered skeletons from Ecuador dating between 500 B.C. and A.D. 1532 are compared with those of normal calculus deposits of individuals from North America (modern and precontact), of normal tooth structure and of samples of alkali recovered from Ecuadorian artifacts thought to have been employed in coca use. Spectral analysis revealed homogeneity among all dental samples (deposits and structure) and that they are distinct from the elemental pattern revealed in the analysis of the artifact alkalis.

scholarly journals Molecular phylogeny and morphologic data of strains of the genus Coelastrella (Chlorophyta, Scenedesmaceae) from a tropical region in North America (Yucatan Peninsula)

2017 ◽  
Vol 95 (3) ◽  
pp. 527 ◽  
Author(s):  
Katia Ancona-Canché ◽  
Silvia López-Adrián ◽  
Margarita Espinosa-Aguilar ◽  
Gloria Garduño-Solórzano ◽  
Tanit Toledano-Thompson ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Phenotypic Plasticity ◽  
North America ◽  
Yucatan Peninsula ◽  
Tropical Region ◽  
Its2 Rdna ◽  
Yucatán Peninsula ◽  
Good Support ◽  
Scanning Electron

<p><strong>Background: </strong>Scenedesmaceae family exhibits great morphological variability. High phenotypic plasticity and the presence of cryptic species have resulted in taxonomic re-assignments of Scenedesmaceae members.</p><p><strong>Study strains: </strong><strong>S</strong>trains CORE-1, CORE-2 and CORE-3 were characterized.</p><p><strong>Study site: </strong>Yucatan Peninsula</p><p><strong>Methods: </strong><strong>Morphological analyses were executed by optical and scanning electron microscopy. P</strong>hylogenetic relationships were examined by ITS-2 and ITS1-5.8S-ITS2 rDNA regions.<strong></strong></p><p><strong>Results:</strong> Optical and scanning electron microscopy analyses indicated spherical to ellipsoidal cells and autospore formation correspond to members of the family Scenedesmaceae, as well as observable pyrenoid starch plates. Detailed morphology analysis indicated that CORE-1 had visible granulations dispersed on the cell wall, suggesting identity with <em>Verrucodesmus verrucosus</em>. However CORE-1 did not show genetic relations with this species, and was instead clustered close to the genus <em>Coelastrella</em>. CORE-2 did not show any particular structure or ornamentation, but it did show genetic relations with <em>Coelastrella</em> with good support. CORE-3 showed meridional ribs from end to end, one of them forked and well pronounced, and orange cells in older cultures characteristic of <em>Coelastrella</em> specimens. Phylogenetic trees of ITS-2 and ITS1-5.8S-ITS2 rDNA sequences indicated with good support that all strains were related to the genus <em>Coelastrella</em> despite their morphologic differences.</p><p><strong>Conclusions: </strong>This study reports freshwater <em>Coelastrella</em> strains from a tropical region in North America (Yucatan Peninsula) for the first time. The results contribute to knowledge of <em>Coelastrella</em> species, and the fact that they do not always show structures that are useful for taxonomic assignment, probably as a result of phenotypic plasticity.</p>

scholarly journals The species of Mentzelia (Loasaceae) in Mexico, part 2: Mentzelia section Bartonia

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
John Schenk ◽  
Carolina Granados Mendoza ◽  
Andres Eduardo Estrada-Castillón
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Species Diversity ◽  
North America ◽  
Species Identification ◽  
Seed Coat ◽  
Western North America ◽  
Distribution Ranges ◽  
Scanning Electron ◽  
Study Species

Background: Mentzelia (Loasaceae) is primarily distributed in western North America. The genus is classified into six monophyletic sections, among which species of section Bartonia are particularly poorly understood. Questions: What species of Mentzelia section Bartonia occur in Mexico? What are the species distribution ranges and what are their defining attributes? Study species: Mentzelia section Bartonia. Methods: Field, herbarium, distribution, and scanning electron microscopy studies were conducted to assess species diversity. Seed coat microsculpture patterns were evaluated to confirm species identities and understand their distributions throughout Mexico. Results: Six species from section Bartonia were recognized, with taxa distributed into either the Chihuahuan or Sonoran deserts. Mentzelia longiloba var. pinacatensis is the only Mexican endemic. Conclusions: Although this work comprehensively addressed the species of section Bartonia in Mexico, two groups will continue to present identification challenges: the M. longiloba and M. mexicana-M. saxicola complexes. Overlapping and variable characters will continue to complicate species identification in the M. longiloba complex, while the late-season loss of primary leaves will obscure species identification between M. mexicana and M. saxicola.

Phyllodistomum umblae (Fabricius) (Digenea, Gorgoderidae) from British Columbia salmonids: a description based on light and scanning electron microscopy

1987 ◽  
Vol 65 (7) ◽  
pp. 1703-1712 ◽  
Author(s):  
T. A. Bakke ◽  
R. E. Bailey
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
British Columbia ◽  
Electron Microscope ◽  
Salmo Salar ◽  
Electron Microscope Study ◽  
Salvelinus Fontinalis ◽  
Salmo Gairdneri ◽  
Scanning Electron Microscope Study ◽  
Scanning Electron

Specimens of Phyllodistomum umblae (Fabricius, 1780) from Oncorhynchus nerka (Walbaum) from the Nautley River, British Columbia, and Salmo gairdneri Richardson from the Stuart River, British Columbia, are described and figured using light microscopy and scanning electron microscopy. Particular emphasis is placed on describing the numbers, types, and arrangement of papillae as seen with scanning electron microscopy. No significant differences were observed between the present Canadian material from O. nerka and S. gairdneri and specimens of P. umblae described from Norway, Sweden, and the U.S.S.R. Thus, P. umblae has a holarctic distribution in salmonids. Phyllodistomum limnosa Sandeman and Pippy, 1967, described from Salmo salar L. and Salvelinus fontinalis (Mitchill) from Newfoundland, is regarded as a synonym of P. umblae. Phyllodistomum lachancei Choquztte, 1947, described from S. fontinalis in Quebec, probably is also a synonym of P. umblae, but a more detailed scanning electron microscope study of the papillae in P. lachancei is required for confirmation.

Trichodina truttae Mueller, 1937 (Ciliophora: Peritrichida), a common pathogenic ectoparasite of cultured juvenile salmonid fishes in British Columbia: redescription and examination by scanning electron microscopy

1984 ◽  
Vol 62 (9) ◽  
pp. 1842-1848 ◽  
Author(s):  
J. R. Arthur ◽  
L. Margolis
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
British Columbia ◽  
Pacific Salmon ◽  
Salmo Gairdneri ◽  
Diagnostic Features ◽  
Detailed Surface ◽  
Juvenile Pacific Salmon ◽  
Oral Surface ◽  
Scanning Electron

The trichodinid ciliate Trichodina truttae Mueller, 1937 is redescribed from silver-impregnated specimens collected from the skin of cultured juvenile Pacific salmon (Oncorhynchus spp.) and steelhead trout (Salmo gairdneri) from British Columbia, and its detailed surface topography was examined by scanning electron microscopy (SEM). Diagnostic features evident by light microscopy are the large size (body diameter 114–179 μm), high denticle number (28–30), and high number (about 20) of radial pins per denticle. Especially noteworthy characters revealed by SEM that may be important for species identification are the presence of radial ridges on the oral surface and two markedly different lengths of cilia within the adoral ciliary spiral. This is the first verified report of T. truttae from Canada.

Gomphosinica selincuoensis sp. nov., a new diatom (Bacillariophyceae) from North Tibet, China

Phytotaxa ◽  
2019 ◽  
Vol 423 (3) ◽  
pp. 195-205 ◽  
Author(s):  
LI YANG ◽  
QING-MIN YOU ◽  
J. P. KOCIOLEK ◽  
LI-QING WANG ◽  
WEI ZHANG
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
New Species ◽  
North America ◽  
The Other ◽  
Central Portion ◽  
Similar Species ◽  
A New Species ◽  
Scanning Electron

A new species, Gomphosinica selincuoensis sp. nov., is described from Lake Selincuo, North Tibet, China. This taxon is clearly different from the other species in genus Gomphosinica, with a distinctly protracted, rostrate headpole, relatively higher striae density, and distinctive areolae arrangement within the striae. Striae have areolae mostly in 3 rows, but there are places near the central portion of the valve and at footpole where there are only 2 rows of areolae per stria. Characteristics of this taxon, as observed in light and scanning electron microscopy, support its systematic placement in the genus Gomphosinica. This new species is compared with similar species in Gomphosinica from China and North America, and the biogeographic distribution of the genus is discussed.

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