scholarly journals Exceptional multifunctionality in the feeding apparatus of a mid-Cambrian radiodont

Paleobiology ◽  
2021 ◽  
pp. 1-21
Author(s):  
Joseph Moysiuk ◽  
Jean-Bernard Caron
Keyword(s):  
Phylogenetic Analysis ◽  
Division Of Labor ◽  
The Body ◽  
Functional Specialization ◽  
Feeding Apparatus ◽  
Burgess Shale ◽  
Crown Group ◽  
Ecological Diversification ◽  
Functional Transition ◽  
Different Parts

Abstract Radiodonts (stem Euarthropoda) were ecologically diverse, but species generally displayed limited functional specialization of appendages along the body axis compared with crown group euarthropods. This is puzzling, because such functional specialization is considered to have been an important driver of euarthropod ecological diversification. One way to circumvent this constraint could have been the functional specialization of different parts of the frontal appendages, known to have been ecologically important in radiodonts. This hypothesis has yet to be tested explicitly. Here we redescribe the poorly known mid-Cambrian hurdiid radiodont Stanleycaris hirpex from the Burgess Shale (Stephen Formation) and quantitatively assess functional specialization of the frontal appendages of stem euarthropods. The appendages of Stanleycaris are composed of 14 podomeres, variously differentiated by their possession of pectinate endites, mono- to trifurcate medial gnathites, and outer spines. The oral cone is tetraradially organized and can be uniquely distinguished from those of other hurdiids by the presence of 28 rather than 32 smooth tridentate plates. Our phylogenetic analysis finds Stanleycaris in a grade of hurdiids retaining plesiomorphic raptorial appendicular functionality alongside derived adaptations for sweep feeding and large, bilaterally opposed gnathites. We conclude that the latter performed a masticatory function, convergent with gnathal structures like mandibles in various panarthropods. Taken together, Stanleycaris and similar hurdiids provide an extreme example of the evolution of division of labor within the appendage of a stem euarthropod and suggest that this innovation may have facilitated the functional transition, from raptorial to sweep feeding, at the origin of the hurdiid clade.

scholarly journals Jaw elements in Plumulites bengtsoni confirm that machaeridians are extinct armoured scaleworms

2019 ◽  
Vol 286 (1907) ◽  
pp. 20191247 ◽  
Author(s):  
Luke A. Parry ◽  
Gregory D. Edgecombe ◽  
Dan Sykes ◽  
Jakob Vinther
Keyword(s):  
Phylogenetic Analysis ◽  
Early Evolution ◽  
The Body ◽  
Common Origin ◽  
Discrete Elements ◽  
Crown Group ◽  
Total Group ◽  
Early Ordovician ◽  
Jaw Apparatus ◽  
Competing Hypotheses

Machaeridians are Palaeozoic animals that are dorsally armoured with serialized, imbricating shell plates that cover or enclose the body. Prior to the discovery of an articulated plumulitid machaeridian from the Early Ordovician of Morocco that preserved unambiguous annelid characters (segmental parapodia with chaetae), machaeridians were a palaeontological mystery, having been previously linked to echinoderms, barnacles, tommotiids (putative stem-group brachiopods) or molluscs. Although the annelid affinities of machaeridians are now firmly established, their position within the phylum and relevance for understanding the early evolution of Annelida is less secure, with competing hypotheses placing Machaeridia in the stem or deeply nested within the crown group of annelids. We describe a scleritome of Plumulites bengtsoni from the Fezouata Formation of Morocco that preserves an anterior jaw apparatus consisting of at least two discrete elements that exhibit growth lines. Although jaws have multiple independent origins within the annelid crown group, comparable jaws are present only within Phyllodocida, the clade that contains modern aphroditiforms (scaleworms and relatives). Phylogenetic analysis places a monophyletic Machaeridia within the crown group of Phyllodocida in total-group Aphroditiformia, consistent with a common origin of machaeridian shell plates and scaleworm elytrae. The inclusion of machaeridians in Aphroditiformia truncates the ghost lineage of Phyllodocida by almost a hundred million years.

scholarly journals A possible case of inverted lifestyle in a new bivalved arthropod from the Burgess Shale

2019 ◽  
Vol 6 (11) ◽  
pp. 191350 ◽  
Author(s):  
Alejandro Izquierdo-López ◽  
Jean-Bernard Caron
Keyword(s):  
Phylogenetic Analysis ◽  
National Park ◽  
Suspension Feeder ◽  
The Body ◽  
Burgess Shale ◽  
Middle Cambrian ◽  
Bayesian Phylogenetic Analysis ◽  
Stem Group ◽  
Potential Case ◽  
Caudal Rami

The origin of the arthropod carapace, an enlargement of cephalic tergites, can be traced back to the Cambrian period. However, its disparity and evolution are still not fully understood. Here, we describe a new ‘bivalved’ arthropod, Fibulacaris nereidis gen. et sp. nov., based on 102 specimens from the middle Cambrian (Wuliuan Stage) Burgess Shale, Marble Canyon area in British Columbia's Kootenay National Park, Canada. The laterally compressed carapace covers most of the body. It is fused dorsally and merges anteriorly into a conspicuous postero-ventrally recurved rostrum as long as the carapace and positioned between a pair of backwards-facing pedunculate eyes. The body is homonomous, with approximately 40 weakly sclerotized segments bearing biramous legs with elongate endopods, and ends in a pair of small flap-like caudal rami. Fibulacaris nereidis is interpreted as a suspension feeder possibly swimming inverted, in a potential case of convergence with some branchiopods. A Bayesian phylogenetic analysis places it within a group closely related to the extinct Hymenocarina. Fibulacaris nereidis is unique in its carapace morphology and overall widens the ecological disparity of Cambrian arthropods and suggests that the evolution of a ‘bivalved' carapace and an upside-down lifestyle may have occurred early in stem-group crustaceans.

The Middle Cambrian metazoan Wiwaxia corrugata (Matthew) from the Burgess Shale and Ogygopsis Shale, British Columbia, Canada

1985 ◽  
Vol 307 (1134) ◽  
pp. 507-582 ◽  
Keyword(s):  
Ventral Surface ◽  
The Body ◽  
Feeding Apparatus ◽  
Burgess Shale ◽  
Significant Similarity ◽  
Middle Cambrian ◽  
Stages Of Growth ◽  
Sea Bed ◽  
Juvenile Specimen ◽  
Early Metazoan

A detailed redescription of the Middle Cambrian metazoan Wiwaxia corrugata (Matthew) is given with the aid of photographs, mostly taken under ultraviolet radiation, and explanatory camera lucida drawings. Wiwaxia is known only from the Stephen Formation with four localities within the Bathyuriscus-Elrathina Zone, the celebrated Burgess Shale (Phyllopod bed) and Ogygopsis Shale and two localities that appear to expose strata relatively high in the Formation, and a new locality in the underlying Glossopleura Zone. Specimens from the Ogygopsis Shale consist almost entirely of isolated sclerites, whereas in the Phyllopod bed the species is also known from entire specimens, semi-isolated assemblages and isolated soft-parts. T he description here is based almost entirely on Phyllopod bed m aterial. Wiwaxia was originally largely covered by sclerites. On the basis of shape and arrangement five distinct zones are recognizable: dorsal, upper lateral, lower lateral, anterior and ventro-lateral. In addition, there was a row of elongate dorso-lateral spinose sclerites running along either side of the body. Each sclerite was inserted separately via a root-like structure. Growth of the animal appears to have occurred by moulting of the sclerites; one unique juvenile specimen appears to be preserved in the act of moulting. The ventral surface was apparently an area of soft tissue devoid of sclerites. Little is known of the internal anatomy, although anteriorly there was a feeding apparatus consisting of two rows of posteriorly directed teeth. Most stages of growth are known varying from presumed juveniles, which at their smallest may have lacked spines, to adults over 50 mm long. Wiwaxia appears to have been an epifaunal deposit feeder that crawled across the sea-bed, although smaller juveniles may have been infaunal. The dorso-lateral spines may have provided protection against predators and the existence of broken spines suggests the successful deterrence of attack. The affinities of Wiwaxia do not appear to lie with the polychaetous annelids. While the possibilities of convergence cannot be eliminated, there appears to be a significant similarity between Wiwaxia and molluscs that suggests a related derivation from a turbellarian ancestor. Nevertheless, Wiwaxia has a distinctive bodyplan and as such cannot be accommodated in any known phylum. While Wiwaxia is unique to the Stephen Formation isolated sclerites from Lower Cambrian rocks appear to represent earlier wiwaxiids, although these sclerites show differences in their size and composition as com pared with Wiwaxia . Wiwaxia enhances knowledge of early metazoan evolution and ecology in the Cambrian. In particular, it gives fresh insights into the origin and relative success of certain metazoan bodyplans, the origin of trace fossils, and the importance of predation in Cambrian communities.

scholarly journals A three-dimensionally preserved lobopodian from the Herefordshire (Silurian) Lagerstätte, UK

2018 ◽  
Vol 5 (8) ◽  
pp. 172101 ◽  
Author(s):  
Derek J. Siveter ◽  
Derek E. G. Briggs ◽  
David J. Siveter ◽  
Mark D. Sutton ◽  
David Legg
Keyword(s):  
Phylogenetic Analysis ◽  
The Body ◽  
New Genera ◽  
Crown Group ◽  
Head Region ◽  
Total Group ◽  
Sister Clade ◽  
Wide Range ◽  
Velvet Worm

The Herefordshire (Silurian) Lagerstätte (approx. 430 Myr BP) has yielded, among many exceptionally preserved invertebrates, a wide range of new genera belonging to crown-group Panarthropoda. Here, we increase this panarthropod diversity with the lobopodian Thanahita distos , a new total-group panarthropod genus and species. This new lobopodian preserves at least nine paired, long, slender appendages, the anterior two in the head region and the posterior seven representing trunk lobopods. The body ends in a short post-appendicular extension. Some of the trunk lobopods bear two claws, others a single claw. The body is covered by paired, tuft-like papillae. Thanahita distos joins only seven other known three-dimensionally preserved lobopodian or onychophoran (velvet worm) fossil specimens and is the first lobopodian to be formally described from the Silurian. Phylogenetic analysis recovered it, together with all described Hallucigenia species, in a sister-clade to crown-group panarthropods. Its placement in a redefined Hallucigeniidae, an iconic Cambrian clade, indicates the survival of this clade to Silurian times.

Updating long-held assumptions about fat stigma: For women, body shape plays a critical role

2020 ◽  
Author(s):  
Jaimie Krems ◽  
Steven L. Neuberg
Keyword(s):  
Body Shape ◽  
Critical Role ◽  
The Body ◽  
Theoretical Assumption ◽  
Obesity Stigma ◽  
Obese Female ◽  
Three Samples ◽  
Female Bodies ◽  
Different Parts ◽  
Fat Stigma

Heavier bodies—particularly female bodies—are stigmatized. Such fat stigma is pervasive, painful to experience, and may even facilitate weight gain, thereby perpetuating the obesity-stigma cycle. Leveraging research on functionally distinct forms of fat (deposited on different parts of the body), we propose that body shape plays an important but largely underappreciated role in fat stigma, above and beyond fat amount. Across three samples varying in participant ethnicity (White and Black Americans) and nation (U.S., India), patterns of fat stigma reveal that, as hypothesized, participants differently stigmatized equally-overweight or -obese female targets as a function of target shape, sometimes even more strongly stigmatizing targets with less rather than more body mass. Such findings suggest value in updating our understanding of fat stigma to include body shape and in querying a predominating, but often implicit, theoretical assumption that people simply view all fat as bad (and more fat as worse).

Study on Pramana Shareera in relation to Prakriti

2016 ◽  
Vol 2 (3) ◽  
Author(s):  
Rajendra Pai N. ◽  
U. Govindaraju
Keyword(s):  
Observational Study ◽  
Upper Limb ◽  
Lower Limb ◽  
Characteristic Property ◽  
The Body ◽  
Artificial Limbs ◽  
Body Parts ◽  
Unit Of Measurement ◽  
The Individual ◽  
Different Parts

Ayurveda in its principle has given importance to individualistic approach rather than generalize. Application of this examination can be clearly seem like even though two patients suffering from same disease, the treatment modality may change depending upon the results of Dashvidha Pariksha. Prakruti and Pramana both used in Dashvidha Pariksha. Both determine the health of the individual and Bala (strength) of Rogi (Patient). Ayurveda followed Swa-angula Pramana as the unit of measurement for measuring the different parts of the body which is prime step assessing patient before treatment. Sushruta and Charaka had stated different Angula Pramana of each Pratyanga (body parts). Specificity is the characteristic property of Swa-angula Pramana. This can be applicable in present era for example artificial limbs. A scientific research includes collection, compilation, analysis and lastly scrutiny of entire findings to arrive at a conclusion. Study of Pramana and its relation with Prakruti was conducted in 1000 volunteers using Prakruti Parkishan proforma with an objective of evaluation of Anguli Pramana in various Prakriti. It was observed co-relating Pramana in each Prakruti and Granthokta Pramana that there is no vast difference in measurement of head, upper limb and lower limb. The observational study shows closer relation of features with classical texts.

scholarly journals Enzymes, Reacting with Organophosphorus Compounds as Detoxifiers: Diversity and Functions

2021 ◽  
Vol 22 (4) ◽  
pp. 1761
Author(s):  
Ilya Lyagin ◽  
Elena Efremenko
Keyword(s):  
Phylogenetic Analysis ◽  
Future Development ◽  
Organophosphorus Compounds ◽  
The Body ◽  
Chemical Transformations ◽  
Negative Consequences ◽  
Biological Targets ◽  
Oxidation Reduction ◽  
Structural Differences ◽  
Living Organisms

Organophosphorus compounds (OPCs) are able to interact with various biological targets in living organisms, including enzymes. The binding of OPCs to enzymes does not always lead to negative consequences for the body itself, since there are a lot of natural biocatalysts that can catalyze the chemical transformations of the OPCs via hydrolysis or oxidation/reduction and thereby provide their detoxification. Some of these enzymes, their structural differences and identity, mechanisms, and specificity of catalytic action are discussed in this work, including results of computational modeling. Phylogenetic analysis of these diverse enzymes was specially realized for this review to emphasize a great area for future development(s) and applications.

scholarly journals Black spicules from a new interstitial opheliid polychaete Thoracophelia minuta sp. nov. (Annelida: Opheliidae)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Naoto Jimi ◽  
Shinta Fujimoto ◽  
Mami Takehara ◽  
Satoshi Imura
Keyword(s):  
Developmental Biology ◽  
Phylogenetic Analysis ◽  
New Species ◽  
Morphological Diversity ◽  
The Body ◽  
Evolutionary Significance ◽  
Research Subject ◽  
Ecological Diversity ◽  
Coelomic Cavity ◽  
Molecular Phylogenetic

AbstractThe phylum Annelida exhibits high morphological diversity coupled with its extensive ecological diversity, and the process of its evolution has been an attractive research subject for many researchers. Its representatives are also extensively studied in fields of ecology and developmental biology and important in many other biology related disciplines. The study of biomineralisation is one of them. Some annelid groups are well known to form calcified tubes but other forms of biomineralisation are also known. Herein, we report a new interstitial annelid species with black spicules, Thoracophelia minuta sp. nov., from Yoichi, Hokkaido, Japan. Spicules are minute calcium carbonate inclusions found across the body and in this new species, numerous black rod-like inclusions of calcium-rich composition are distributed in the coelomic cavity. The new species can be distinguished from other known species of the genus by these conspicuous spicules, shape of branchiae and body formula. Further, the new species’ body size is apparently smaller than its congeners. Based on our molecular phylogenetic analysis using 18S and 28S sequences, we discuss the evolutionary significance of the new species’ spicules and also the species' progenetic origin.

Respiratory disease in foreign body aspiration in children

1927 ◽  
Vol 23 (11) ◽  
pp. 1145-1150
Author(s):  
G. M. Lopatin
Keyword(s):  
Foreign Body ◽  
Respiratory Tract ◽  
Respiratory Disease ◽  
Foreign Bodies ◽  
Foreign Body Aspiration ◽  
The Body ◽  
Different Parts

Aspiration of foreign bodies into the windpipe usually results in respiratory damage. This lesion may be of varying intensity and may be localized in different parts of the respiratory tract or lungs. Both the intensity and the localization of the lesion may depend on a number of reasons and above all on the location of the foreign body and its type, but also on the constitutional characteristics of the body and on many other causes. Aspirated foreign bodies are found in the trachea or larynx and almost as often in the bronchi.

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