64 research outputs found
The early Cambrian fossil embryo <i>Pseudooides </i>is a direct developing cnidarian, not an early ecdysozoan
Exceptionally Preserved Jellyfishes from the Middle Cambrian
Cnidarians represent an early diverging animal group and thus insight into their origin and diversification is key to understanding metazoan evolution. Further, cnidarian jellyfish comprise an important component of modern marine planktonic ecosystems. Here we report on exceptionally preserved cnidarian jellyfish fossils from the Middle Cambrian (âŒ505 million years old) Marjum Formation of Utah. These are the first described Cambrian jellyfish fossils to display exquisite preservation of soft part anatomy including detailed features of structures interpreted as trailing tentacles and subumbrellar and exumbrellar surfaces. If the interpretation of these preserved characters is correct, their presence is diagnostic of modern jellyfish taxa. These new discoveries may provide insight into the scope of cnidarian diversity shortly after the Cambrian radiation, and would reinforce the notion that important taxonomic components of the modern planktonic realm were in place by the Cambrian period
Cryptic Disc Structures Resembling Ediacaran Discoidal Fossils from the Lower Silurian Hellefjord Schist, Arctic Norway
The Hellefjord Schist, a volcaniclastic psammite-pelite formation in the Caledonides of Arctic Norway contains discoidal impressions and apparent tube casts that share morphological and taphonomic similarities to Neoproterozoic stem-holdfast forms. U-Pb zircon geochronology on the host metasediment indicates it was deposited between 437 ± 2 and 439 ± 3 Ma, but also indicates that an inferred basal conglomerate to this formation must be part of an older stratigraphic element, as it is cross-cut by a 546 ± 4 Ma pegmatite. These results confirm that the Hellefjord Schist is separated from underlying older Proterozoic rocks by a thrust. It has previously been argued that the Cambrian Substrate Revolution destroyed the ecological niches that the Neoproterozoic frond-holdfasts organisms occupied. However, the discovery of these fossils in Silurian rocks demonstrates that the environment and substrate must have been similar enough to Neoproterozoic settings that frond-holdfast bodyplans were still ecologically viable some hundred million years later
The Swiss Preschoolersâ health study (SPLASHY): objectives and design of a prospective multi-site cohort study assessing psychological and physiological health in young children
Alternative interpretations of some earliest Ediacaran fossils from China
In a letter to Nature (February, 2011), Xunlai Yuan and colâ
laborators recorded carbon compression fossils from black
shales of the Lantian Formation (Ediacaran), southern
Anhui Province, South China. The new fossils, described
under five morphological types (Types A to E), exhibit deâ
grees of morphological differentiation suggesting that they
were multicellular eukaryotes. Some of the Lantian macroâ
fossils were interpreted as algae, but others are of unknown
affinities. For reasons noted in this discussion, Type A fossils
attracted our particular attention, and we suggest an alterâ
native interpretation of their affinities. According to our
view, some of them (at least those with three faces and no
globose holdfast at their base) may represent conulariid cniâ
darians or close medusozoan relatives. The undistorted orâ
ganism probably was a threeâsided cone in life. We believe
that our suggested alternative interpretations of the anatâ
omy and affinities of the fossils in question can be useful in
guiding future research on the oldest currently known fossil
assemblage of multicellular organisms
Cladistics and mass extinctions: the example of conulariids (Scyphozoa, Cnidaria) and the End Ordovician Extinction Event
Clonal colony in the Early Devonian cnidarian Sphenothallus from Brazil
The fossil record of polypoid cnidarians includes a number of taxa that were incorrectly identified as either tubiculous worms or plants. The holotype of the putative alga Euzebiola clarkei (Ponta Grossa Formation, Lower Devonian, Brazil), originally described under the name Serpulites sica, is re-described and re-figured as a species of Sphenothallus, a medusozoan cnidarian. Unlike Sphenothallus from other localities, the black, organic-walled Ponta Grossa specimen consists of a single parent tube that is confluent with the apical ends of at least 18 daughter tubes. The pattern of arrangement of the daughter tubes, which are arrayed in single file along the exposed face and the two thickened margins of the parent tube, partly resembles the whorl-like pattern of arrangement of colonial polyps of certain scyphozoan cnidarians. For these reasons, the Ponta Grossa Formation material figures prominently in the argument that Sphenothallus was a medusozoan cnidarian capable (in at least one species) of clonal budding
Administration of the German Pediatric Evaluation of Disability Inventory (PEDI-G) Using the Mode of Observation in Children Undergoing Inpatient Rehabilitation: A Reliability and Validity Study
Aims: To investigate inter-rater reliability, concurrent validity, and feasibility of the German Pediatric Evaluation of Disability Inventory (PEDI-G) using the mode of observation in a Swiss inpatient rehabilitation setting with the Functional Independence Measure for Children (WeeFIMÂź) as criterion.Methods: Cross-sectional clinimetric study including 36 children and adolescents with median age 10.8 (quartiles 8.7, 13.0) years with neurological/neuro-orthopedic disorders. Data were collected by healthcare professionals through observation. Analyses were performed using intraclass correlation coefficients (ICC2,1), standard error of measurement (SEMAgreement), Bland-Altman plots, Cohen's Kappa Îș, percentage agreement, and correlations.Results: Excellent inter-rater reliability (ICCs2,1 â„ 0.97), small SEMs and acceptable limits of agreement for the Functional Skills Scale (FSS) and Caregiver Assistance Scale (CAS) were found. No systematic differences between raters existed. Cohen's Kappa for inter-rater agreement of the Modifications Scale (MS) ranged from poor to strong (-0.06 †Îș â€0.85). Excellent concurrent validity for FSS and CAS with the WeeFIMÂź (Ï ââ„â0.96), and excellent correlations of FSS and CAS with each other (Ï ââ„â0.98) were identified.Conclusion: The German PEDI-G seems to be a reliable and valid, but time-consuming tool when applied in an inpatient setting using observation
Reinterpretation of a conulariid-like fossil from the Vendian of Russia
Vendoconularia triradiata Ivantsov and Fedonkin, recently described from Vendian (latest Proterozoic) strata of Russia, has been interpreted as a six-sided conulariid cnidarian. However, comparison of published illustrations of V. triradiata with Palaeozoic conulariids suggests that certain key features of the anatomy of V. triradiata should be reinterpreted. Specifically, features previously homologized with the corners of conulariid thecae may actually be homologous to the conulariid midlines. Under this new interpretation, the corners of the Vendoconularia theca were sulcate, and the midline of each face was non-sulcate and flanked by a pair of low internal carinae. This alternative set of hypotheses of homology makes the argument for a conulariid affinity for Vendoconularia stronger
Administration of the German Pediatric Evaluation of Disability Inventory (PEDI-G) Using the Mode of Observation in Children Undergoing Inpatient Rehabilitation:A Reliability and Validity Study
Aims: To investigate inter-rater reliability, concurrent validity, and feasibility of the German Pediatric Evaluation of Disability Inventory (PEDI-G) using the mode of observation in a Swiss inpatient rehabilitation setting with the Functional Independence Measure for Children (WeeFIM (R)) as criterion. Methods: Cross-sectional clinimetric study including 36 children and adolescents with median age 10.8 (quartiles 8.7, 13.0) years with neurological/neuro-orthopedic disorders. Data were collected by healthcare professionals through observation. Analyses were performed using intraclass correlation coefficients (ICC2,1), standard error of measurement (SEMAgreement), Bland-Altman plots, Cohen's Kappa kappa, percentage agreement, and correlations. Results: Excellent inter-rater reliability (ICCs2,1 >= 0.97), small SEMs and acceptable limits of agreement for the Functional Skills Scale (FSS) and Caregiver Assistance Scale (CAS) were found. No systematic differences between raters existed. Cohen's Kappa for inter-rater agreement of the Modifications Scale (MS) ranged from poor to strong (-0.06 = 0.96), and excellent correlations of FSS and CAS with each other (rho >= 0.98) were identified. Conclusion: The German PEDI-G seems to be a reliable and valid, but time-consuming tool when applied in an inpatient setting using observation
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