scholarly journals Limb reduction in squamate reptiles correlates with the reduction of the chondrocranium: A case study on serpentiform anguids

2021 ◽  
Author(s):  
Oleksandr Yaryhin ◽  
Jozef Klembara ◽  
Yuriy Pichugin ◽  
Marketa Kaucka ◽  
Ingmar Werneburg
Keyword(s):  
Squamate Reptiles ◽  
Limb Reduction

Ancestral state reconstructions require biological evidence to test evolutionary hypotheses: A case study examining the evolution of reproductive mode in squamate reptiles

2015 ◽  
Vol 324 (6) ◽  
pp. 493-503 ◽  
Author(s):  
Oliver W. Griffith ◽  
Daniel G. Blackburn ◽  
Matthew C. Brandley ◽  
James U. Van Dyke ◽  
Camilla M. Whittington ◽  
...  
Keyword(s):  
Reproductive Mode ◽  
Ancestral State ◽  
Squamate Reptiles ◽  
Biological Evidence

scholarly journals Digit evolution in gymnophthalmid lizards

2015 ◽  
Author(s):  
Juliana Roscito ◽  
Pedro M. S. Nunes ◽  
Miguel T Rodrigues
Keyword(s):  
Sonic Hedgehog ◽  
Limb Development ◽  
Current Knowledge ◽  
Expression Patterns ◽  
Molecular Signaling ◽  
Digit Number ◽  
Squamate Reptiles ◽  
Limb Reduction ◽  
Developmental Mechanisms ◽  
The Many

Background The tetrapod limb is a highly diverse structure, and reduction of the limbs accounts for much of the phenotypes observed within species. Squamate reptiles represent one of the many lineages in which the limbs have been greatly modified from the pentadactyl generalized pattern; within the group, limb-reduced morphologies can vary from minor reductions in size of elements to complete limblessness, with several intermediate forms in between. Even though limb reduction is widespread, it is not clear what are the evolutionary and developmental mechanisms involved in the formation of reduced limb morphologies. Methods In this study, we present an overview of limb morphology within the microteiid lizard group Gymnophthalmidae, focusing on digit number. Results We show that there are two major groups of limb-reduced gymnophthalmids. The first group is formed by lizard-like - and frequently pentadactyl - species, in which minor reductions (such as the loss of 1-2 phalanges mainly in digits I and V) are the rule; these morphologies generally correspond to those seen in other squamates. The second group is formed by species showing more drastic losses, which can include the absence of an externally distinct limb in adults. We also show the expression patterns of Sonic Hedgehog (Shh) in the greatly reduced fore and hindlimb of a serpentiform gymnophthalmid. Conclusions Our discussion focus on identifying shared patterns of limb reduction among tetrapods, and explaining these patterns and the morphological variation within the gymnophthalmids based on the current knowledge of the molecular signaling pathways that coordinate limb development.

scholarly journals phyloregion: R package for biogeographic regionalization and spatial conservation

2020 ◽  
Author(s):  
Barnabas H. Daru ◽  
Piyal Karunarathne ◽  
Klaus Schliep
Keyword(s):  
R Package ◽  
Rapid Identification ◽  
Optimal Number ◽  
List Type ◽  
Squamate Reptiles ◽  
Biogeographic Regionalization ◽  
Evolutionary Distinctiveness ◽  
Classification Of Regions ◽  
User Friendly

SummaryBiogeographical regionalization is the classification of regions in terms of their biotas and is key to understanding biodiversity patterns across the world. Previously, it was only possible to perform analysis of biogeographic regionalization on small datasets, often using tools that are difficult to replicate.Here, we present phyloregion, a package for the analysis of biogeographic regionalization and spatial conservation in the R computing environment, tailored for mega phylogenies and macroecological datasets of ever-increasing size and complexity.Compared to available packages, phyloregion is three to four orders of magnitude faster and memory efficient for cluster analysis, determining optimal number of clusters, evolutionary distinctiveness of regions, as well as analysis of more standard conservation measures of phylogenetic diversity, phylogenetic endemism, and evolutionary distinctiveness and global endangerment.A case study of zoogeographic regionalization for 9574 species of squamate reptiles (amphisbaenians, lizards, and snakes) across the globe, reveals their evolutionary affinities, using visualization tools that allow rapid identification of patterns and underlying processes with user-friendly colours–for example– indicating the levels of differentiation of the taxa in different regions.Ultimately, phyloregion would facilitate rapid biogeographic analyses that accommodates the ongoing mass-production of species occurrence records and phylogenetic datasets at any scale and for any taxonomic group into completely reproducible R workflows.

Cornelia de Lange Syndrome: A Case Study

2002 ◽  
Vol 21 (3) ◽  
pp. 7-13 ◽  
Author(s):  
Melanie Melanie
Keyword(s):  
Growth Retardation ◽  
Cornelia De Lange Syndrome ◽  
Facial Features ◽  
Cognitive Limitations ◽  
Limb Reduction ◽  
Cornelia De Lange ◽  
The Many ◽  
Term Management

Cornelia de Lange syndrome (CdLS) is a rare dysmorphogenic disorder characterized by growth retardation, severe cognitive limitations, distinctive facial features, and limb reduction anomalies recognizable at birth. Currently, no single criterion is diagnostic for CdLS, and misdiagnosis is not uncommon. Long-term management of the infant with CdLS requires a coordinated effort among many different specialists. This article presents a general overview of Cornelia de Lange syndrome. It concludes with a case study illustrating the many problems infants with CdLS may have and the great amount of teaching and support that is needed by families affected by CdLS.

The Genesis and Internal Dynamics of El Salvador's People's Revolutionary Army, 1970–1976

2014 ◽  
Vol 38 (01) ◽  
pp. 102-129
Author(s):  
ALBERTO MARTÍN ÁLVAREZ ◽  
EUDALD CORTINA ORERO
Keyword(s):  
Latin America ◽  
El Salvador ◽  
Early Years ◽  
Left Wing ◽  
Internal Dynamics ◽  
Internal Coherence ◽  
The 1960S

AbstractUsing interviews with former militants and previously unpublished documents, this article traces the genesis and internal dynamics of the Ejército Revolucionario del Pueblo (People's Revolutionary Army, ERP) in El Salvador during the early years of its existence (1970–6). This period was marked by the inability of the ERP to maintain internal coherence or any consensus on revolutionary strategy, which led to a series of splits and internal fights over control of the organisation. The evidence marshalled in this case study sheds new light on the origins of the armed Salvadorean Left and thus contributes to a wider understanding of the processes of formation and internal dynamics of armed left-wing groups that emerged from the 1960s onwards in Latin America.

Culture and the plasticity of perception

2020 ◽  
Vol 43 ◽  
Author(s):  
Michael Lifshitz ◽  
T. M. Luhrmann
Keyword(s):  
Cultural Context ◽  
Sensory Experience ◽  
Cultural Learning ◽  
The World

Abstract Culture shapes our basic sensory experience of the world. This is particularly striking in the study of religion and psychosis, where we and others have shown that cultural context determines both the structure and content of hallucination-like events. The cultural shaping of hallucinations may provide a rich case-study for linking cultural learning with emerging prediction-based models of perception.

Dual systems for all: Higher-order, role-based relational reasoning as a uniquely derived feature of human cognition

2019 ◽  
Vol 42 ◽  
Author(s):  
Daniel J. Povinelli ◽  
Gabrielle C. Glorioso ◽  
Shannon L. Kuznar ◽  
Mateja Pavlic
Keyword(s):  
Temporal Reasoning ◽  
Higher Order ◽  
Important Case ◽  
Human Cognition ◽  
Relational Reasoning ◽  
Dual Systems ◽  
First Order ◽  
Reasoning System ◽  
Role Based

Abstract Hoerl and McCormack demonstrate that although animals possess a sophisticated temporal updating system, there is no evidence that they also possess a temporal reasoning system. This important case study is directly related to the broader claim that although animals are manifestly capable of first-order (perceptually-based) relational reasoning, they lack the capacity for higher-order, role-based relational reasoning. We argue this distinction applies to all domains of cognition.

Sociocultural memory development research drives new directions in gadgetry science

2019 ◽  
Vol 42 ◽  
Author(s):  
Penny Van Bergen ◽  
John Sutton
Keyword(s):  
Episodic Memory ◽  
Autobiographical Memory ◽  
Developmental Psychology ◽  
Cross Cultural ◽  
Memory Development ◽  
Development Research ◽  
Cultural Research ◽  
New Directions ◽  
Cross Cultural Research

Abstract Sociocultural developmental psychology can drive new directions in gadgetry science. We use autobiographical memory, a compound capacity incorporating episodic memory, as a case study. Autobiographical memory emerges late in development, supported by interactions with parents. Intervention research highlights the causal influence of these interactions, whereas cross-cultural research demonstrates culturally determined diversity. Different patterns of inheritance are discussed.

Construction of plastic contact deformation maps on ceramics: a case study on aluminum nitride

1996 ◽  
Vol 54 ◽  
pp. 636-637
Author(s):  
D. L. Callahan
Keyword(s):  
Plastic Deformation ◽  
Aluminum Nitride ◽  
Mechanical Response ◽  
Three Dimensional ◽  
Bright Field Image ◽  
Perfectly Plastic ◽  
Contrast Analysis ◽  
Deformation Patterns

Modern polishing, precision machining and microindentation techniques allow the processing and mechanical characterization of ceramics at nanometric scales and within entirely plastic deformation regimes. The mechanical response of most ceramics to such highly constrained contact is not predictable from macroscopic properties and the microstructural deformation patterns have proven difficult to characterize by the application of any individual technique. In this study, TEM techniques of contrast analysis and CBED are combined with stereographic analysis to construct a three-dimensional microstructure deformation map of the surface of a perfectly plastic microindentation on macroscopically brittle aluminum nitride.The bright field image in Figure 1 shows a lg Vickers microindentation contained within a single AlN grain far from any boundaries. High densities of dislocations are evident, particularly near facet edges but are not individually resolvable. The prominent bend contours also indicate the severity of plastic deformation. Figure 2 is a selected area diffraction pattern covering the entire indentation area.

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