Reexamination of Yuknessia from the Cambrian of China and first report of Fuxianospira from North America

2015 ◽  
Vol 89 (6) ◽  
pp. 899-911 ◽  
Author(s):  
Steven T. LoDuca ◽  
Mengyin Wu ◽  
Yuanlong Zhao ◽  
Shuhai Xiao ◽  
James D. Schiffbauer ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
North America ◽  
Type Species ◽  
Burgess Shale ◽  
Shale Formations ◽  
Chinese Study ◽  
Shale Formation ◽  
Chengjiang Biota ◽  
Stratigraphic Range ◽  
Scanning Electron

AbstractYuknessia Walcott, 1919 recently was transferred from the green algae to the Phylum Hemichordata on the basis of new details observed for the type species, Y. simplex, from the Burgess Shale Formation (Cambrian Stage 5) of British Columbia. This has prompted reexamination of material attributed to Yuknessia from various Cambrian localities in South China. Findings preclude both a Yuknessia and a hemichordate affinity for all of the Chinese study material, and most of this material is formally transferred to Fuxianospira Chen and Zhou, 1997, a taxon common in the Chengjiang biota. Comparable material from the Cambrian Marjum, Wheeler, and Burgess Shale formations of North America is also assigned to Fuxianospira, and this reassignment expands both the paleogeographic and stratigraphic range of this taxon. All aspects of the study specimens, including details obtained from scanning electron microscopy, are consistent with an algal affinity, as proposed in the original descriptions of the Chinese material.

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.

Rare primitive deuterostomes from the Cambrian (Series 3) of Utah

2015 ◽  
Vol 89 (4) ◽  
pp. 631-636 ◽  
Author(s):  
Simon Conway Morris ◽  
Susan L. Halgedahl ◽  
Paul Selden ◽  
Richard D. Jarrard
Keyword(s):  
New Species ◽  
Fossil Record ◽  
Type Species ◽  
The Body ◽  
New Taxon ◽  
Burgess Shale ◽  
Anterior Section ◽  
Stem Group ◽  
Stratigraphic Range ◽  
New Discovery

AbstractThe fossil record of early deuterostome history largely depends on soft-bodied material that is generally rare and often of controversial status. Banffiids and vetulicystids exemplify these problems. From the Cambrian (Series 3) of Utah, we describe specimens of Banffia episoma n. sp. (from the Spence Shale) and Thylacocercus ignota n. gen. n. sp. (from the Wheeler Formation). The new species of Banffia Walcott, 1911 shows significant differences to the type species (B. constricta Walcott, 1911) from the Cambrian (Series 3, Stage 5) Burgess Shale, notably in possessing a prominent posterior unit but diminished anterior section. Not only does this point to a greater diversity of form among the banffiids, but also B. episoma indicates that the diagnostic median constriction and crossover of either side of the body are unlikely to be the result of taphonomic twisting but are original features. Comparisons extend also to the Cambrian (Series 2) Heteromorphus Luo and Hu in Luo et al., 1999 and, collectively, these observations support an assignment of the banffiids to the vetulicolians. The new taxon T. ignota represents the first discovery of a vetulicystid from beyond China and also significantly extends its stratigraphic range from Series 2 Cambrian into Series 3 Cambrian. Despite overall similarities in bodyplan, T. ignota differs from other vetulicystids in a number of respects, notably the possession of an anterior zone with broad tentacle-like structures. This new discovery is consistent with the vetulicystids representing stem-group ambulacrarians.

Structure of the cephalic end of two little-known oxyuroid genera, Travnema Pereira, 1938 and Cosmoxynemoides Travassos, 1949, parasites of fishes, as revealed by SEM

1994 ◽  
Vol 68 (4) ◽  
pp. 319-322 ◽  
Author(s):  
F. Moravec ◽  
A. Kohn ◽  
B.M.M. Fernandes
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Type Species ◽  
Freshwater Fishes ◽  
The Other ◽  
New Host ◽  
The Family ◽  
Cephalic Extremity ◽  
New Host Records ◽  
Scanning Electron

AbstractThe cephalic end of the type species of pharyngodonid genera Travnema and Cosmoxynemoides, T. travnema Pereira, 1938 and C. aguirrei Travassos, 1949, parasites of Brazilian freshwater fishes, was studied by scanning electron microscopy. The mouth aperture of Travnema was found to be circular, surrounded by four cephalic papillae and two lateral amphids and the cuticle of the cephalic end had a conspicuous dense sculpture. On the other hand, the mouth aperture of Cosmoxynemoides was triangular, surrounded by three lip-like elevations covering the whole surface of the relatively flat cephalic extremity, each with two inner lobes separated one from another by a short groove; the lip-like elevations bore four medium-sized, kidney-shaped cephalic papillae and two minute amphids (two papillae on the dorsal elevation and one papilla and one amphid on each of two ventrolateral elevations); the cuticle of the cephalic end was smooth. Both species were noted for the absence of oral lamellae and the presence of lateral alae. Both genera are listed in the family Pharyngodonidae but Travnema (and also Hakynema), due to its morphological peculiarities, is considered to represent a distinct subfamily Travnematinae within the Pharyngodonidae. The finding of both T. travnema and C. aguirrei in the characid fish Astyanax bimaculatus lacustris represents new host records.

New occurrences of the Pennsylvanian index ammonoidDunbaritesfrom the North American midcontinent

2009 ◽  
Vol 83 (3) ◽  
pp. 405-413 ◽  
Author(s):  
David M. Work ◽  
Royal H. Mapes
Keyword(s):  
North America ◽  
Type Species ◽  
Additional Species ◽  
North Central ◽  
The North ◽  
South Central ◽  
West Texas ◽  
Kasimovian Stage ◽  
New Occurrences ◽  
Stratigraphic Range

Ten newly recoveredDunbaritesspecimens significantly extend the known stratigraphic range ofDunbarites.These include the first documented Midcontinent Basin records of the Missourian type speciesDunbarites rectilateralis(Miller, 1930) from north-central Oklahoma. Additional species ofDunbaritesfrom south-central Oklahoma and north-central and West Texas are described asDunbarites wewokensisn. sp. andDunbarites boardmanin. sp. AlthoughDunbaritesis an extremely rare component (~0.025 percent) of Middle and Upper Pennsylvanian ammonoid assemblages, Ruzhencev and Bogoslovskaya (1971, 1978) suggested thatDunbaritesandParashumarditesRuzhencev, 1939 be used as genozone markers for the Kasimovian [Zhigulevian] Stage (Missourian in North America). As demonstrated by this report, the range ofDunbaritesis not confined to the Kasimovian, thereby precluding its use as a Kasimovian Stage indicator.

Revised taxonomy and redescription of two species of the Peripatidae (Onychophora) from Brazil: a step towards consistent terminology of morphological characters

Zootaxa ◽  
2010 ◽  
Vol 2493 (1) ◽  
pp. 16 ◽  
Author(s):  
IVO DE SENA OLIVEIRA ◽  
ALFREDO HANNEMANN WIELOCH ◽  
GEORG MAYER
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Type Species ◽  
Morphological Characters ◽  
Type Material ◽  
Taxon Sampling ◽  
The Caribbean ◽  
Dermal Papillae ◽  
Scanning Electron

Based on the supposed quadrangular shape of the basal pieces of dorsal primary papillae, several species of the “Caribbean group” of the neotropical Peripatidae, including Macroperipatus acacioi and M. machadoi, were assigned to Macroperipatus. So far, the quadrangular shape of dermal papillae was confirmed only for M. torquatus, the type species of the genus. Previous observations revealed that the putatively quadrangular shape reported from other species of the “Caribbean group” might be a fixation artefact. Hence, detailed reinvestigations of all putative Macroperipatus species are required to clarify their taxonomy. In the present study, two species of the “Caribbean group”, M. acacioi and M. machadoi, are analyzed and redescribed, based on type material and topotype specimens collected at the corresponding type localities. The original descriptions of both species are complemented with data obtained from scanning electron microscopy, in addition to conventional morphological methods. The quadrangular bases of primary papillae are shown to be absent from M. acacioi and M. machadoi, thus suggesting that these two species are not closely related to M. torquatus. The new data instead suggest that these two species are representatives of Epiperipatus: E. acacioi comb. nov. and E. machadoi comb. nov.. The present study highlights the use of scanning electron microscopy for clarifying the taxonomy and phylogeny of the neotropical Peripatidae. It also reveals gaps in taxon sampling and problems regarding the ambiguous terminology of morphological characters used for describing the anatomy of peripatids. An attempt is made towards a consistent terminology for species (re)descriptions and studies of onychophoran anatomy and phylogeny.

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.

Re-investigation of Polyoeca dichotoma and Acanthoeca spectabilis (Acanthoecidae: Choanoflagellida)

1984 ◽  
Vol 64 (4) ◽  
pp. 819-827 ◽  
Author(s):  
Shigemitsu Hara ◽  
Eiji Takahashif
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Type Species ◽  
New Genus ◽  
Three Dimensional ◽  
Electron Microscopical ◽  
Scanning Electron

Light and electron microscopical reinvestigation of Polyoeca dichotoma Kent revealed that Acanthoecopsis spiculifera Norris, the type species of the genus, is a synonym for Polyoeca dichotoma. Since this step invalidates the use of the name Acanthoecopsis, a new genus Acanthocorbis was established for the three species formerly included in Acanthoecopsis.The three dimensional arrangement of costal strips forming the loricae of Polyoeca dichotoma and Acanthoeca spectabilis Ellis were examined by scanning electron microscopy. The arrangement of costal strips were similar in both species. The longitudinal costal strips and those forming the spines were arranged outside the supplementary costae and those of the transverse bonds.

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 Supplemental Material: Early formation and taphonomic significance of kaolinite associated with Burgess Shale fossils

2020 ◽  
Author(s):  
Ross Anderson ◽  
et al.
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Antibacterial Properties ◽  
Energy Dispersive ◽  
Burgess Shale ◽  
X Ray Diffraction ◽  
X Ray ◽  
Early Formation ◽  
Data Tables ◽  
Scanning Electron

Supplemental methodological details, antibacterial properties of clays, other minerals with distinct fossil/matrix distributions, summaries of mineralogy by taxon, data tables, statistical summaries, and light/scanning electron microscopy–energy-dispersive X-ray spectroscopy images of fossil specimens showing X-ray diffraction selected areas.<br>

scholarly journals Fruit morphology, anatomy and relationships of the type species of Mastixicarpum and Eomastixia (Cornales) from the late Eocene of Hordle, southern England

2019 ◽  
Vol 59 (1) ◽  
pp. 51-67 ◽  
Author(s):  
Steven R. Manchester ◽  
Margaret E. Collinson
Keyword(s):  
Electron Microscopy ◽  
Fossil Record ◽  
Type Species ◽  
Late Eocene ◽  
Fruit Morphology ◽  
Type Specimens ◽  
X Ray ◽  
Extant Genus ◽  
Extinct Genus ◽  
Scanning Electron

Abstract The Mastixiaceae (Cornales) were more widespread and diverse in the Cenozoic than they are today. The fossil record includes fruits of both extant genera, Mastixia and Diplopanax, as well as several extinct genera. Two of the fossil genera, Eomastixia and Mastixicarpum, are prominent in the palaeobotanical literature, but concepts of their delimitation have varied with different authors. These genera, both based on species described 93 years ago by Marjorie Chandler from the late Eocene (Priabonian) Totland Bay Member of the Headon Hill Formation at Hordle, England, are nomenclaturally fundamental, because they were the first of a series of fossil mastixioid genera published from the European Cenozoic. In order to better understand the type species of Eomastixia and Mastixicarpum, we studied type specimens and topotypic material using x-ray tomography and scanning electron microscopy to supplement traditional methods of analysis, to improve our understanding of the morphology and anatomy of these fossils. Following comparisons with other fossil and modern taxa, we retain Mastixicarpum crassum Chandler rather than transferring it to the similar extant genus Diplopanax, and we retain Eomastixia bilocularis Chandler [=Eomastixia rugosa (Zenker) Chandler] and corroborate earlier conclusions that this species represents an extinct genus that is more closely related to Mastixia than to Diplopanax.

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