Analysis of variation in the Elaphrus americanus complex of North America (Coleoptera: Carabidae)

1981 ◽  
Vol 59 (12) ◽  
pp. 2253-2274 ◽  
Author(s):  
Henri Goulet ◽  
Bernard R. Baum
Keyword(s):  
North America ◽  
Univariate Analysis ◽  
Principal Component ◽  
Evolutionary Significance ◽  
Mahalanobis Distances ◽  
Taxonomic Analysis ◽  
Principal Component Analyses ◽  
Discriminant Analyses ◽  
Euclidean Distances ◽  
Analysis Of Variation

Elaphrus americanus Dejean (sensu Lindroth, 1961) is a complex of two nearctic species: E. americanus and E. finitimus Casey. This study is primarily devoted to E. americanus, which includes two subspecies: a boreal subspecies and a newly described western subspecies, E. americanus sylvanus Goulet n. subsp., for which the type locality is Oregon, Coos Co., 16 miles north of Powers.The species and subspecies mentioned above were recognized by means of numerical taxonomic analysis. Most intuitively acceptable were the results of phenetic clustering of Mahalanobis distances followed by a series of discriminant analyses. Various analyses were carried out based directly on computed euclidean distances, e.g. principal coordinate analyses, nonmetric multidimensional scaling, and still others by computing first the variance–covariance matrix, e.g., principal component analyses. Other geographically distinct populations were recognized by univariate analysis of nominal characters.Phylogenetic relationships between various populations of E. americanus are partly reconstructed. A reconstruction of past distribution of these populations is presented and their evolutionary significance discussed.

Geographic variation of the Anderson’s Niviventer (Niviventer andersoni) (Thomas, 1911) (Rodentia: Muridae) of two new subspecies in China verified with cranial morphometric variables and pelage characteristics

Zootaxa ◽  
2009 ◽  
Vol 2196 (1) ◽  
pp. 48-58 ◽  
Author(s):  
SONG LI ◽  
JUNXING YANG
Keyword(s):  
Geographic Variation ◽  
Yunnan Province ◽  
Principal Component ◽  
Taxonomic Revision ◽  
Western Yunnan ◽  
Principal Component Analyses ◽  
Discriminant Analyses ◽  
Southern Shaanxi ◽  
First Time ◽  
Northwestern Yunnan

A total of 66 specimens of Niviventer andersoni with intact skulls was investigated on pelage characteristics and cranial morphometric variables. The data were subjected to principal component analyses as well as to discriminant analyses, and measurement overlap was studied as compared with the coefficient of difference. The results indicate that three subspecies of N. andersoni can be recognized in China, including N. a. andersoni broadly distributed from northwestern Yunnan, Sichuan, northward to southern Shaanxi, and eastward to Hubei, N. a. pianmaensis subsp. nov. in western Yunnan, and N. a. ailaoshanensis subsp. nov. in Mt. Ailaoshan, central Yunnan province. Our study for the first time validates its subspecies differentiation that is most likely related to intra-specific geographic variation. In addition, a taxonomic revision of Niviventer andersoni in China is described.

Analysis of variation in the Elaphrus finitimus complex of North America (Coleoptera: Carabidae)

1982 ◽  
Vol 60 (10) ◽  
pp. 2424-2433 ◽  
Author(s):  
Henri Goulet ◽  
Bernard R. Baum
Keyword(s):  
Sierra Nevada ◽  
Great Basin ◽  
Colorado Plateau ◽  
Univariate Analysis ◽  
White Mountains ◽  
Mahalanobis Distances ◽  
Central California ◽  
Pair Group ◽  
Limited Gene Flow ◽  
Analysis Of Variation

This is a continuation of a study on geographical variation of the Elaphrus americanus Dejean species complex. This paper is devoted to E. finitimus Casey, which includes at least seven populations: White Mountains of California, Colorado Plateau, western Great Basin, western Arizona, central California, southern California, and southern Sierra Nevada. Three main groups of populations were recognized by means of numerical taxonomic analyses: White Mountains of California (one population), Intermontane (Colorado Plateau and western Great Basin), and southwestern (remaining four populations). The above groups were discerned from clustering by UPGMA (unweighted pair group using arithmetic averages) of Mahalanobis distances, and are characterized in a discriminant analysis. Other geographically distinct populations were recognized by univariate analysis of nominal characters. All seven populations are allopatric and are isolated presently from one another by vast expanses of dry regions (prairies and piñon–juniper woodlands), or by different life zones with altitude. We postulated that during the glacial phases of the Pleistocene similar barriers existed, though the gaps were narrower than at present. The reconstructed glacial ranges of these populations offer a hypothesis as to the origin of some populations, and direction of limited gene flow between some populations.

Élaboration d'un coefficient de résistance au gui chez le chêne

1992 ◽  
Vol 70 (6) ◽  
pp. 1239-1246 ◽  
Author(s):  
E. B. Hariri ◽  
B. Jeune ◽  
S. Baudino ◽  
K. Urech ◽  
G. Sallé
Keyword(s):  
Quercus Robur ◽  
Quercus Rubra ◽  
Resistance Mechanism ◽  
Principal Component ◽  
Viscum Album ◽  
Quercus Petraea ◽  
Resistance Coefficient ◽  
Principal Component Analyses ◽  
Discriminant Analyses ◽  
Forest Managers

The reactions of oak to mistletoe (Viscum album L.) were studied using about 100 sensitive and susceptible oak twigs belonging to three species of oak: Quercus robur, Quercus rubra, and Quercus petraea. The main parameters likely to be involved in the resistance mechanism to mistletoe were measured on longitudinal radial sections. After conducting several principal component analyses and discriminant analyses, four variables were shown to have high discriminant values: thickness of the cortex, density of polyphenol-containing cells, thickness of the first layers of fibers, and thickness of collenchyma. Statistical analyses were performed using a large number of samples to define a discriminating function linking the four variables and to propose a resistance coefficient. The significance of such a coefficient for forest managers and pharmacologists is discussed in relation to their own needs. Key words: Viscum album, Quercus, resistance coefficient, mistletoe.

Morphometrics and Redescription of Aphyllon fasciculatum and Aphyllon franciscanum, Two Widespread but Previously Conflated Species in Western North America

2021 ◽  
Vol 46 (2) ◽  
pp. 446-455
Author(s):  
Adam C. Schneider ◽  
Ben E. Benton
Keyword(s):  
North America ◽  
Principal Component ◽  
Calyx Lobe ◽  
Corolla Tube ◽  
Herbarium Specimens ◽  
Western North America ◽  
Widespread Species ◽  
Floral Color ◽  
Discriminant Analyses ◽  
Floral Characters

Abstract— We continue the taxonomic reevaluation of Aphyllon sect. Aphyllon by describing a widespread species throughout western North America previously recognized within a polyphyletic A. fasciculatum. To support our description and revised key, we analyzed fifteen continuous and discrete characters sampled from 186 herbarium specimens and iNaturalist observations representing the geographic and host ranges. Principal component and multiple correspondence analyses reveal clear variation in floral characters. Discriminant analyses show that three aspects of floral color, corolla lobe tip shape, the calyx cup to calyx lobe ratio, calyx lobe length, and degree of bend in the corolla tube are useful distinguishing features, but not diagnostic in every case.

Multivariate analysis of the hybrid Phoxinus eos × Phoxinus neogaeus (Pisces: Cyprinidae): reevaluation of univariate analysis

1989 ◽  
Vol 67 (7) ◽  
pp. 1637-1641
Author(s):  
Gerard R. Joswiak ◽  
John G. New
Keyword(s):  
Univariate Analysis ◽  
Principal Component ◽  
The Other ◽  
Morphological Data ◽  
Multivariate Methods ◽  
Morphometric Measurements ◽  
Data Set ◽  
Principal Component Analyses ◽  
Two Factors ◽  
The Mean

Morphological data from two species of minnows, Phoxinus eos and Phoxinus neogaeus, and their hybrids (Pisces: Cyprinidae), previously analyzed by univariate methods, were reanalyzed by multivariate methods. Stepwise discriminant and principal component analyses were conducted on a data set of 14 morphometric measurements from 172 specimens. All of the Phoxinus neogaeus and 87% of both hybrids and Phoxinus eos were correctly classified on functions derived from six discriminating variables. Principal component analysis resulted in the extraction of two factors that explained 90% of the variation in the data set. Mean scores on the first factor were significantly different for P. eos, while on the second factor the mean score for P. neogaeus differed from those of the other two groups. Possible causes of variation in the morphology in the Phoxinus hybrids, from diploidy, tripoloidy, and mosaicism, are discussed.

The variation of angles between anterior and posterior carinae of tyrannosaurid teeth

2012 ◽  
Vol 49 (3) ◽  
pp. 477-491 ◽  
Author(s):  
Miriam Reichel
Keyword(s):  
Strong Correlation ◽  
Multivariate Analyses ◽  
Principal Component ◽  
Tooth Size ◽  
Data Set ◽  
In Situ Data ◽  
Principal Component Analyses ◽  
Canonical Variates ◽  
Discriminant Analyses

Tyrannosaurid tooth measurements have been shown to be a powerful tool for systematic analyses, as well as for studies on function and evolution of theropod dentition. In this analysis, a variable not previously addressed in depth is added to the tyrannosaurid data set. The angle between the anterior and posterior carinae can be difficult to measure consistently and a method is hereby proposed through the use of a digitizer. Five tyrannosaurid genera were analyzed: Tyrannosaurus , Tarbosaurus , Albertosaurus , Daspletosaurus , and Gorgosaurus . Only in situ data were used, and therefore some of the taxa had a limited amount of information available for this analysis. The measurements were analyzed through multivariate analyses using Paleontological Statistics (PAST), version 2.06. The analyses included principal component analyses (PCAs), discriminant analyses (DAs), and canonical variates analyses (CVAs). The results of these analyses revealed that the angle between carinae contributes significantly to the variation in the tyrannosaurid tooth data set. Additionally, this variable showed a strong correlation to tooth function (and, consequently, to tooth families), rather than tooth size. The variation observed between taxa at this stage seems insufficient for systematic purposes, however additional in situ data would help improve the effectiveness of this tool.

Le statut des Euphrasia borealis, E. nemorosa et E. stricta dans l'est de l'Amérique du Nord : une analyse numérique

1988 ◽  
Vol 66 (11) ◽  
pp. 2208-2216
Author(s):  
Stephen R. Downie ◽  
Andrée Quintin ◽  
John McNeill
Keyword(s):  
North America ◽  
Principal Component ◽  
Taxonomic Status ◽  
Single Species ◽  
Morphological Characters ◽  
Data Matrix ◽  
Cauline Leaf ◽  
Operational Taxonomic Units ◽  
Considerable Controversy ◽  
Discriminant Analyses

The taxonomic status of Euphrasia borealis, E. nemorosa, and E. stricta in eastern North America has been the subject of considerable controversy. A sample of 184 operational taxonomic units were scored for 58 morphological characters, and the resulting data matrix was subjected to cluster and principal component analyses. Two groups were recognized on the basis of bract and upper cauline leaf characters and designated as E. nemorosa and E. stricta. These two groups were then subjected to several discriminant analyses (stepwise, linear, and canonical) using quantitative data. The results do not support the recognition of E. borealis and E. nemorosa as separate taxa. These plants should be treated as a single species, for which the correct name is E. nemorosa. Euphrasia stricta is, however, morphologically distinct from E. nemorosa. Some geographic differentiation was observed between plants of E. nemorosa from Newfoundland and those from Quebec, but not enough to warrant the recognition of infraspecific taxa. No evidence of hybridization between E. nemorosa and E. stricta was found. Key words: Euphrasia borealis, Euphrasia nemorosa, Euphrasia stricta, numerical analysis, North America, hybridization.

scholarly journals Fast diffusion kurtosis mapping of human brain at 7 Tesla with hybrid principal component analyses

IEEE Access ◽  
2021 ◽  
pp. 1-1
Author(s):  
Fangrong Zong ◽  
Jiaxin Du ◽  
Xiaofeng Deng ◽  
Xubin Chai ◽  
Yan Zhuo ◽  
...  
Keyword(s):  
Human Brain ◽  
Principal Component ◽  
7 Tesla ◽  
Fast Diffusion ◽  
Principal Component Analyses ◽  
Diffusion Kurtosis
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