scholarly journals Onychophoran-like musculature in a phosphatized Cambrian lobopodian

2016 ◽  
Vol 12 (9) ◽  
pp. 20160492 ◽  
Author(s):  
Xi-Guang Zhang ◽  
Martin R. Smith ◽  
Jie Yang ◽  
Jin-Bo Hou
Keyword(s):  
Phylogenetic Analysis ◽  
Muscle Tissue ◽  
Three Dimensional ◽  
Body Plan ◽  
Early Cambrian ◽  
First Report ◽  
Rich Diversity ◽  
The Rich

The restricted, exclusively terrestrial distribution of modern Onychophora contrasts strikingly with the rich diversity of onychophoran-like fossils preserved in marine Cambrian Lagerstätten . The transition from these early forebears to the modern onychophoran body plan is poorly constrained, in part owing to the absence of fossils preserving details of the soft anatomy. Here, we report muscle tissue in a new early Cambrian (Stage 3) lobopodian, Tritonychus phanerosarkus gen. et sp. nov., preserved in the Orsten fashion by three-dimensional replication in phosphate. This first report of Palaeozoic onychophoran musculature establishes peripheral musculature as a characteristic of the ancestral panarthropod, but documents an unexpected muscular configuration. Phylogenetic analysis reconstructs T. phanerosarkus as one of a few members of the main onychophoran lineage—which was as rare and as cryptic in the Cambrian period as it is today.

scholarly journals The early Cambrian fossil embryo Pseudooides is a direct-developing cnidarian, not an early ecdysozoan

2017 ◽  
Vol 284 (1869) ◽  
pp. 20172188 ◽  
Author(s):  
Baichuan Duan ◽  
Xi-Ping Dong ◽  
Luis Porras ◽  
Kelly Vargas ◽  
John A. Cunningham ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Developmental Stages ◽  
Radial Symmetry ◽  
Body Plan ◽  
Direct Development ◽  
Early Cambrian ◽  
Germ Band ◽  
Stages Of Development ◽  
Bayesian Phylogenetic Analysis ◽  
Indirect Development

Early Cambrian Pseudooides prima has been described from embryonic and post-embryonic stages of development, exhibiting long germ-band development. There has been some debate about the pattern of segmentation, but this interpretation, as among the earliest records of ecdysozoans, has been generally accepted. Here, we show that the ‘germ band’ of P. prima embryos separates along its mid axis during development, with the transverse furrows between the ‘somites’ unfolding into the polar aperture of the ten-sided theca of Hexaconularia sichuanensis , conventionally interpreted as a scyphozoan cnidarian; co-occurring post-embryonic remains of ecdysozoans are unrelated. We recognize H. sichuanensis as a junior synonym of P. prima as a consequence of identifying these two form-taxa as distinct developmental stages of the same organism. Direct development in P. prima parallels the co-occuring olivooids Olivooides, and Quadrapyrgites and Bayesian phylogenetic analysis of a novel phenotype dataset indicates that, despite differences in their tetra-, penta- and pseudo-hexa-radial symmetry, these hexangulaconulariids comprise a clade of scyphozoan medusozoans, with Arthrochites and conulariids, that all exhibit direct development from embryo to thecate polyp. The affinity of hexangulaconulariids and olivooids to extant scyphozoan medusozoans indicates that the prevalence of tetraradial symmetry and indirect development are a vestige of a broader spectrum of body-plan symmetries and developmental modes that was manifest in their early Phanerozoic counterparts.

scholarly journals Making a stronger case for comparative research to investigate the behavioral and neurological bases of three-dimensional navigation

2013 ◽  
Vol 36 (5) ◽  
pp. 557-558 ◽  
Author(s):  
Daniele Nardi ◽  
Verner P. Bingman
Keyword(s):  
Natural History ◽  
Comparative Research ◽  
Three Dimensional ◽  
Bird Species ◽  
Comparative Approach ◽  
Rich Diversity ◽  
The Rich

AbstractThe rich diversity of avian natural history provides exciting possibilities for comparative research aimed at understanding three-dimensional navigation. We propose some hypotheses relating differences in natural history to potential behavioral and neurological adaptations possessed by contrasting bird species. This comparative approach may offer unique insights into some of the important questions raised by Jeffery et al.

scholarly journals Hyoliths with pedicles illuminate the origin of the brachiopod body plan

2018 ◽  
Vol 285 (1887) ◽  
pp. 20181780 ◽  
Author(s):  
Haijing Sun ◽  
Martin R. Smith ◽  
Han Zeng ◽  
Fangchen Zhao ◽  
Guoxiang Li ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Feeding Ecology ◽  
Body Plan ◽  
Phylogenetic Position ◽  
Suspension Feeding ◽  
Total Group ◽  
First Report ◽  
Single Origin ◽  
Bivalve Shell ◽  
Chengjiang Lagerstätte

Hyoliths are a taxonomically problematic group of Palaeozoic lophotrochozoans that are among the first shelly fossils to appear in the Cambrian period. On the basis of their distinctive exoskeleton, hyoliths have historically been classified as a separate phylum with possible affinities to the molluscs, sipunculans or lophophorates—but their precise phylogenetic position remains uncertain. Here, we describe a new orthothecide hyolith from the Chengjiang Lagerstätte (Cambrian Series 2 Stage 3), Pedunculotheca diania Sun, Zhao et Zhu gen. et sp. nov., which exhibits a non-mineralized attachment structure that strikingly resembles the brachiopod pedicle—the first report of a peduncular organ in hyoliths. This organ establishes a sessile, suspension feeding ecology for these orthothecides and—together with other characteristics (e.g. bilaterally symmetrical bivalve shell enclosing a filtration chamber and the differentiation of cardinal areas)—identifies hyoliths as stem-group brachiopods. Our phylogenetic analysis indicates that both hyoliths and crown brachiopods derived from a tommotiid grade, and that the pedicle has a single origin within the brachiopod total group.

Conclusion

2018 ◽  
Author(s):  
Stefan Winter
Keyword(s):  
Middle Eastern ◽  
Rich Diversity ◽  
The Social ◽  
Local Contexts ◽  
History Of ◽  
Religious Oppression ◽  
The Rich ◽  
To Come

This concluding chapter summarizes key themes and presents some final thoughts. The book has shown that the multiplicity of lived ʻAlawi experiences cannot be reduced to the sole question of religion or framed within a monolithic narrative of persecution; that the very attempt to outline a single coherent history of “the ʻAlawis” may indeed be misguided. The sources on which this study has drawn are considerably more accessible, and the social and administrative realities they reflect consistently more mundane and disjointed, than the discourse of the ʻAlawis' supposed exceptionalism would lead one to believe. Therefore, the challenge for historians of ʻAlawi society in Syria and elsewhere is not to use the specific events and structures these sources detail to merely add to the already existing metanarratives of religious oppression, Ottoman misrule, and national resistance but rather to come to a newer and more intricate understanding of that community, and its place in wider Middle Eastern society, by investigating the lives of individual ʻAlawi (and other) actors within the rich diversity of local contexts these sources reveal.

PSYCHOLOGICAL FEATURES OF EDUCATION AND TOLERANCE IN STUDENTS

2018 ◽  
Vol 16 (1) ◽  
pp. 112-119
Author(s):  
VLADIMIR GLEB NAYDONOV
Keyword(s):  
Statistical Analysis ◽  
Training Program ◽  
Rich Diversity ◽  
Interethnic Differences ◽  
The World ◽  
The Rich ◽  
Correct Understanding ◽  
Psychological Features ◽  
Different Levels

The article considers the students’ tolerance as a spectrum of personal manifestations of respect, acceptance and correct understanding of the rich diversity of cultures of the world, values of others’ personality. The purpose of the study is to investgate education and the formation of tolerance among the students. We have compiled a training program to improve the level of tolerance for interethnic differences. Based on the statistical analysis of the data obtained, the most important values that are significant for different levels of tolerance were identified.

scholarly journals Biosynthetic potential of uncultured Antarctic soil bacteria revealed through long-read metagenomic sequencing

2021 ◽  
Author(s):  
Valentin Waschulin ◽  
Chiara Borsetto ◽  
Robert James ◽  
Kevin K. Newsham ◽  
Stefano Donadio ◽  
...  
Keyword(s):  
Genome Mining ◽  
Gene Clusters ◽  
Biosynthetic Gene Cluster ◽  
Full Length ◽  
Metagenomic Sequencing ◽  
Short Read ◽  
Short Read Sequencing ◽  
Rich Diversity ◽  
Long Read ◽  
The Rich

AbstractThe growing problem of antibiotic resistance has led to the exploration of uncultured bacteria as potential sources of new antimicrobials. PCR amplicon analyses and short-read sequencing studies of samples from different environments have reported evidence of high biosynthetic gene cluster (BGC) diversity in metagenomes, indicating their potential for producing novel and useful compounds. However, recovering full-length BGC sequences from uncultivated bacteria remains a challenge due to the technological restraints of short-read sequencing, thus making assessment of BGC diversity difficult. Here, long-read sequencing and genome mining were used to recover >1400 mostly full-length BGCs that demonstrate the rich diversity of BGCs from uncultivated lineages present in soil from Mars Oasis, Antarctica. A large number of highly divergent BGCs were not only found in the phyla Acidobacteriota, Verrucomicrobiota and Gemmatimonadota but also in the actinobacterial classes Acidimicrobiia and Thermoleophilia and the gammaproteobacterial order UBA7966. The latter furthermore contained a potential novel family of RiPPs. Our findings underline the biosynthetic potential of underexplored phyla as well as unexplored lineages within seemingly well-studied producer phyla. They also showcase long-read metagenomic sequencing as a promising way to access the untapped genetic reservoir of specialised metabolite gene clusters of the uncultured majority of microbes.

scholarly journals Petiole-Lamina Transition Zone: A Functionally Crucial but Often Overlooked Leaf Trait

Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 774
Author(s):  
Max Langer ◽  
Thomas Speck ◽  
Olga Speck
Keyword(s):  
Transition Zone ◽  
Three Dimensional ◽  
Spatial Arrangement ◽  
Body Plan ◽  
The Body ◽  
Vascular Bundles ◽  
Cross Sectional ◽  
Thin Sections ◽  
Transition Zones ◽  
The Cross

Although both the petiole and lamina of foliage leaves have been thoroughly studied, the transition zone between them has often been overlooked. We aimed to identify objectively measurable morphological and anatomical criteria for a generally valid definition of the petiole–lamina transition zone by comparing foliage leaves with various body plans (monocotyledons vs. dicotyledons) and spatial arrangements of petiole and lamina (two-dimensional vs. three-dimensional configurations). Cross-sectional geometry and tissue arrangement of petioles and transition zones were investigated via serial thin-sections and µCT. The changes in the cross-sectional geometries from the petiole to the transition zone and the course of the vascular bundles in the transition zone apparently depend on the spatial arrangement, while the arrangement of the vascular bundles in the petioles depends on the body plan. We found an exponential acropetal increase in the cross-sectional area and axial and polar second moments of area to be the defining characteristic of all transition zones studied, regardless of body plan or spatial arrangement. In conclusion, a variety of terms is used in the literature for describing the region between petiole and lamina. We prefer the term “petiole–lamina transition zone” to underline its three-dimensional nature and the integration of multiple gradients of geometry, shape, and size.

New olenelline trilobites from the Northwest Territories, Canada, and the phylogenetic placement of Judomia absita Fritz, 1973

Zootaxa ◽  
2011 ◽  
Vol 2918 (1) ◽  
pp. 15 ◽  
Author(s):  
I. WESLEY GAPP ◽  
BRUCE S. LIEBERMAN ◽  
MICHAEL C. POPE ◽  
KELLY A. DILLIARD
Keyword(s):  
Phylogenetic Analysis ◽  
New Species ◽  
Northwest Territories ◽  
Phylogenetic Analyses ◽  
Geographic Range ◽  
Early Cambrian ◽  
Phylogenetic Placement ◽  
The Subject ◽  
Three New Species ◽  
One New Species

The Early Cambrian olenelline trilobites are a diverse clade and have been the subject of several phylogenetic analyses. Here, three new species of Bradyfallotaspis Fritz, 1972 (B. coriae, B. nicolascagei, and B. sekwiensis) and one new species of Nevadia Walcott, 1910 (N. saupeae) are described from the Sekwi Formation of the Mackenzie Mountains, Northwest Territories, Canada. In addition, new specimens potentially referable to Nevadia ovalis McMenamin, 1987 were recovered that may expand that species’ geographic range, which was thought to be restricted to Sonora, Mexico. The results of a phylogenetic analysis incorporating several olenelline taxa, including Judomia absita Fritz, 1973 from the Sekwi Formation, are also presented herein. This species has been assigned to various olenelline genera, including Judomia Lermontova, 1951 and Paranevadella Palmer & Repina, 1993. Phylogenetic analysis suggests this species is closely related to Judomia tera Lazarenko, 1960 from Siberia. This phylogenetic relationship provides further support for the hypothesis that a close biogeographic relationship existed between Laurentia and Siberia during the Cambrian.

scholarly journals Pivoting the Plant Immune System from Dissection to Deployment

Science ◽  
2013 ◽  
Vol 341 (6147) ◽  
pp. 746-751 ◽  
Author(s):  
Jeffery L. Dangl ◽  
Diana M. Horvath ◽  
Brian J. Staskawicz
Keyword(s):  
Immune System ◽  
Conceptual Understanding ◽  
Germ Plasm ◽  
Plant Diseases ◽  
Sequencing Technology ◽  
Plant Immune System ◽  
Rich Diversity ◽  
The World ◽  
The Rich ◽  
Molecular Components

Diverse and rapidly evolving pathogens cause plant diseases and epidemics that threaten crop yield and food security around the world. Research over the last 25 years has led to an increasingly clear conceptual understanding of the molecular components of the plant immune system. Combined with ever-cheaper DNA-sequencing technology and the rich diversity of germ plasm manipulated for over a century by plant breeders, we now have the means to begin development of durable (long-lasting) disease resistance beyond the limits imposed by conventional breeding and in a manner that will replace costly and unsustainable chemical controls.

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