scholarly journals Morphometric variation in two intertidal littorinid gastropods

2011 ◽  
Vol 80 (3) ◽  
pp. 201-211 ◽  
Author(s):  
Henrique Queiroga ◽  
Rolando Costa ◽  
Nélia Leonardo ◽  
Débora Soares ◽  
Daniel F.R. Cleary
Keyword(s):  
Statistical Analysis ◽  
Spatial Variation ◽  
Procrustes Analysis ◽  
Shell Shape ◽  
Morphometric Variation ◽  
Landmark Data ◽  
Components Analysis ◽  
Individual Size ◽  
Eggs And Larvae ◽  
Melarhaphe Neritoides

Here we investigate spatial variation in shell shape of Littorina saxatilis, an ovoviviparous species, and Melarhaphe neritoides, a species with planktonic eggs and larvae. Populations of both species were sampled in 6 sites located along the west coast of the Iberian Peninsula. Shell shape was studied using landmarkbased morphometric methods. Landmark data was used to estimate individual size and to describe shell shape. Prior to statistical analysis specimens were aligned using Generalised Procrustes Analysis (GPA). Ordinations based on GPA of landmark data and using Principal Components Analysis (PCA), revealed a clear spatial segregation of sites for both species, although this was more evident for L. saxatilis than M. neritoides. Statistical analysis revealed significant multivariate variation in shape among sites and a significant effect of allometry on shape for both species. In contrast to this last result, there was no significant linear relationship between any of the first three PC axes and size in L. saxatilis but highly significant associations between the first and third PC axes and size for M. neritoides. Spatial variation in the shape of both species was primarily related to variation in the height of the apical whorls and in the width of the aperture for L. saxatilis. Further variation in shape was related to the shape of the last whorl in L. saxatilis and shell elongation and a change in aperture shape in M. neritoides.

Morphometric variation of fish scales among some species of rattail fish from New Zealand waters

2018 ◽  
Vol 98 (8) ◽  
pp. 1991-1998
Author(s):  
A. L. Ibáñez ◽  
L. A. Jawad
Keyword(s):  
New Zealand ◽  
Discriminant Analysis ◽  
Morphological Evolution ◽  
Procrustes Analysis ◽  
Fish Scales ◽  
Geometric Morphometric ◽  
Morphometric Variation ◽  
Generalized Procrustes Analysis ◽  
Morphometric Methods ◽  
Components Analysis

New Zealand rattail fish are of great interest both to biologists who study their phylogenetics and in fisheries. In contrast, their morphological evolution is little studied and poorly understood. Geometric morphometric methods based on scale shape were applied in this study to determine differences among species and genera. Scale shapes were described using seven landmarks, the coordinates of which were subjected to a generalized Procrustes analysis, followed by a principal components analysis. A cross-validated discriminant analysis was applied to assess and compare the size-shape (centroid size plus shape variables) efficacy in the species and the discrimination of the genera. Two main phenetic groups were identified: cluster no. 1 with eight species and cluster no. 2 with six species. Coelorhinchus aspercephalus and Mesovagus antipodum were more separated from the other species in the first cluster. The cross-validated canonical discriminant analysis correctly classified 74% at the genus level, with most misclassifications occurring between Coelorhinchus and Coryphaenoides, whereas the best classified genera were Mesovagus and Trachyrincus. The discrimination of correctly classified species ranged from 41.2 to 100%. The highest correct classification rates were recorded for Coryphaenoides armatus, Coelorhinchus innotabilis, Trachyrincus longirostris and Mesovagus antipodum.

scholarly journals Morphometric variation among sardine (Sardina pilchardus) populations from the northeastern Atlantic and the western Mediterranean

2003 ◽  
Vol 60 (6) ◽  
pp. 1352-1360 ◽  
Author(s):  
Alexandra Silva
Keyword(s):  
Test Sample ◽  
Western Mediterranean ◽  
Morphometric Variation ◽  
Closed Population ◽  
Landmark Data ◽  
Test Fish ◽  
Southern Iberia ◽  
Components Analysis ◽  
And Cluster Analysis ◽  
Northeastern Atlantic

Abstract During the past decade, regional changes in the dynamics of the Atlanto-Iberian stock of sardine, and its exploitation by Portuguese and Spanish purse-seine fisheries, have increased the uncertainties in estimated trends of spawning biomass, stock abundance, and fishing mortality. Together with recent evidence for lack of discontinuities in the distribution of sardine eggs at the edges of the stock area, this casts doubts on the hypothesis that the stock is a panmictic, closed population. Sardine morphometric data (truss variables and landmark data) from 14 samples spanning the northeastern Atlantic and the western Mediterranean were analysed by multivariate and geometric methods. The analyses explored the homogeneity of sardine shape within the area studied, as well as its relation to that of adjacent and distant populations (Azores and northwestern Mediterranean). Principal components analysis on size-corrected truss variables and cluster analysis of mean fish shape using landmark data indicate that the shape of sardine off southern Iberia and Morocco is distinct from the shape of sardine in the rest of the area. The two groups of sardine are significantly separated by discriminant analysis, and their validity was confirmed by large percentages of correct classifications of test fish (87 and 86% of fish from the test sample were correctly classified into each group, respectively). There was also some evidence that fish from the western Mediterranean and the Azores form a separate morphometric group. These results question both the homogeneity within the Atlanto-Iberian sardine stock and the validity of its current boundaries.

scholarly journals Morphometric Analysis of Cranial Shape in Fossil and Recent Euprimates

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
C. Verity Bennett ◽  
Anjali Goswami
Keyword(s):  
Function Analysis ◽  
Cranial Morphology ◽  
Evolutionary Patterns ◽  
Linear Discriminant ◽  
Landmark Data ◽  
Components Analysis ◽  
Fossil Primates ◽  
Procrustes Superimposition ◽  
Linear Discriminant Function Analysis ◽  
3D Landmarks

Quantitative analysis of morphology allows for identification of subtle evolutionary patterns or convergences in anatomy that can aid ecological reconstructions of extinct taxa. This study explores diversity and convergence in cranial morphology across living and fossil primates using geometric morphometrics. 33 3D landmarks were gathered from 34 genera of euprimates (382 specimens), including the Eocene adapiforms Adapis and Leptadapis and Quaternary lemurs Archaeolemur, Palaeopropithecus, and Megaladapis. Landmark data was treated with Procrustes superimposition to remove all nonshape differences and then subjected to principal components analysis and linear discriminant function analysis. Haplorhines and strepsirrhines were well separated in morphospace along the major components of variation, largely reflecting differences in relative skull length and width and facial depth. Most adapiforms fell within or close to strepsirrhine space, while Quaternary lemurs deviated from extant strepsirrhines, either exploring new regions of morphospace or converging on haplorhines. Fossil taxa significantly increased the area of morphospace occupied by strepsirrhines. However, recent haplorhines showed significantly greater cranial disparity than strepsirrhines, even with the inclusion of the unusual Quaternary lemurs, demonstrating that differences in primate cranial disparity are likely real and not simply an artefact of recent megafaunal extinctions.

Environmental and taxonomic variation in fingernail clam (Bivalvia: Pisidiidae) shell morphology

1983 ◽  
Vol 61 (12) ◽  
pp. 2781-2788 ◽  
Author(s):  
R. C. Bailey ◽  
E. H. Anthony ◽  
G. L. Mackie
Keyword(s):  
Correlation Matrix ◽  
Shell Morphology ◽  
Multivariate Statistical Techniques ◽  
Multivariate Statistical ◽  
Morphometric Variation ◽  
Running Water ◽  
Components Analysis ◽  
Generic Groups ◽  
Fingernail Clams

Variation in the shell morphology of Sphaerium and Musculium fingernail clams was examined using multivariate statistical techniques. On the basis of shell measurements alone, clams from either genera which were collected in running-water habitats could be distinguished, with over 90% accuracy, from clams inhabiting standing water. The discrimination between the two groups was mainly due to the greater size and thickness of shells from clams living in running water. The pisidiid genera Sphaerium and Musculium were also morphologically distinguishable, mainly by size. Morphometric classification of these groups also resulted in over a 90% success rate. The morphometric variation within each of the above groups was further compared using a principal components analysis of each group's morphometric correlation matrix. This analysis revealed differences in growth-related changes in form between the pairs of habitat and generic groups studied. The techniques used to compare ecologically or taxonomically distinct shells appear to be promising for use in either biological monitoring or habitat selection studies.

scholarly journals Os fatores geoecológicos, geourbanos e o clima urbano de Iporá-GO: uma análise a partir do Método de Correlação Linear

2018 ◽  
Vol 11 (3) ◽  
pp. 77
Author(s):  
Washington Silva Alves ◽  
Zilda De Fátima Mariano
Keyword(s):  
Statistical Analysis ◽  
Spatial Variation ◽  
Statistical Methods ◽  
Air Temperature ◽  
Urban Climate ◽  
Temperature Data ◽  
Absolute Minimum ◽  
El Sistema ◽  
Weather Stations ◽  
Maximum Air Temperature

Resumo O objetivo desse trabalho consistiu em analisar a influência dos fatores geoecológicos e geourbanos no padrão da temperatura do ar máxima e mínima absoluta em Iporá-GO, por meio do método estatístico de correlação linear. Os fundamentos teóricos e metodológicos pautaram-se no sistema clima urbano de Monteiro (2003), com ênfase no subsistema termodinâmico. Os fatores geoecológicos (hipsometria, exposição de vertente, vegetação urbana e hidrografia) e geourbanos (densidade de construção e o uso do solo urbano), foram georreferenciado com auxílio dos softwares ArcGis 9.0, Spring 5.3 e Surfer 9.0. Os dados de temperatura do ar foram coletados entre outubro de 2012 e outubro de 2013, em intervalos de 30 minutos, com termohigrômetros (modelo HT-500) e estações meteorológicas automáticas distribuídos em seis pontos da área urbana e rural de Iporá. Posteriormente, os dados foram organizados em planilhas de cálculos para análise estatística. Os resultados demonstraram que os fatores geoecológicos e geourbanos citados foram decisivos na variação espacial da temperatura do ar máxima e mínima absoluta em Iporá.Palavras-chave: Climatologia, Cidade, Clima Urbano AbstractThe objective of this study is to analyze the influence of geoecological factors and geourbanos the standard maximum air temperature and absolute minimum in Iporá-GO, by means of statistical methods of correlation linear. The theoretical and methodological foundations guided in the urban climate system Monteiro (2003), with emphasis on thermodynamic subsystem. The geoecological factors (hipsometria, slop exposure, urban and Hydrography vegetation) and geourban (building density and the use of urban land), were georeferenced with the help of software ArcGIS 9.0, Sprint 5.3 and Surfer 9.0. The air temperature data were collected between October 2012 and October 2013, in 30-minute intervals, with hygrometer term (HT-500 model) and automatic weather stations distributed in six points of the urban and rural Iporá. Later, the data were organized into spreadsheets for statistical analysis. The results showed that geoecological mentioned factors and geourbanos were decisive in the spatial variation of the temperature of the air and maximum absolute minimum in Iporá.Keywords: Climatology, City, Urban Climate ResumenEl objetivo de este estudio fue analizar la influencia de los factores geoecológicos y geourbanos en el patrón de la temperatura máxima y mínima absoluta del aire en Iporá-GO, a través de lo método estadístico de correlación lineal. Los fundamentos teóricos y metodológicos se basan en el sistema de clima urbano de Monteiro (2003), con énfasis en el subsistema termodinámico. Los factores geoecológicos (hipsometría, hebras de exposición, hidrografía y vegetación urbana) y geourbanos (densidad de edificación y uso del suelo urbano) fueron georeferenciados con la ayuda del software ArcGIS 9.0, Spring 5.3 y Surfer 9.0. Los datos de temperatura del aire se recogieron entre octubre 2012 y octubre 2013, en intervalos de 30 minutos, con termohigrômetros (modelo HT-500) y estaciones meteorológicas automáticas distribuidas en seis puntos de las zonas urbanas y rurales. Posteriormente, los datos se organizaron en las hojas de cálculo para el análisis estadístico. Los resultados mostraron que los factores geoecológicos y geourbanos citados fueron decisivos en la variación espacial de la temperatura máxima y mínima absoluta del aire en Iporá.Palavras clave: Climatología, Ciudad, Clima Urbano 

Multivariate Statistical Analysis of Flat Vowel Spectra With a View to Characterizing Dysphonic Voices

2000 ◽  
Vol 43 (6) ◽  
pp. 1493-1508 ◽  
Author(s):  
Jean Schoentgen ◽  
Mounir Bensaid ◽  
Fabrizio Bucella
Keyword(s):  
Statistical Analysis ◽  
Principal Components ◽  
Multivariate Statistical Analysis ◽  
Heuristic Search ◽  
Vocal Tract ◽  
Multivariate Statistical ◽  
Magnitude Spectrum ◽  
Spectral Contour ◽  
Components Analysis ◽  
Different Levels

The aim of this article is to show how dysphonic voices can be characterized by means of a multivariate statistical analysis of flat vowel spectra. The spectral contour was obtained by means of a wavelet transform of the logarithmic magnitude spectrum, which was subsequently flattened to remove interspeaker variability related to the excitation and vocal tract filter functions. The results of the statistical analysis of flat spectra were the following. Firstly, principal components analysis produced markers that separated noisy from clean spectra. Secondly, the heuristic search for harmonic peaks or interharmonic dips could be omitted. Thirdly, conventional spectral markers of noise appeared as special instances of the markers that were derived statistically. Fourthly, the levels of visually assigned hoarseness and the first two principal components were significantly correlated. The assignment of different levels of (visual) hoarseness to different vowel timbres could be explained by the variability associated with the spectral contour.

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