Eigenshape analysis of microfossils: A general morphometric procedure for describing changes in shape

Lohmann, G. P.

doi:10.1007/bf01033230

Cited by 207 publications

(141 citation statements)

References 20 publications

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“…Examples of methods for this include Fourier analyses [275][276][277], eigenshape analysis [278][279][280], semilandmarks [202,205,281,282], and a variety of methods of superimposing 3D surfaces to an overall best fit [104,203,204,283,284]. Note that, even though some authors have claimed that such methods are "homology-free" [285], all these approaches are based in one way or another on a one-to-one correspondence of points on the outline or surface, which is the basis for the computations of mutual fit or difference between shapes [286].…”

Section: Outline Methodsmentioning

confidence: 99%

Analyzing Fluctuating Asymmetry with Geometric Morphometrics: Concepts, Methods, and Applications

2015

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Approximately two decades after the first pioneering analyses, the study of shape asymmetry with the methods of geometric morphometrics has matured and is a burgeoning field. New technology for data collection and new methods and software for analysis are widely available and have led to numerous applications in plants and animals, including humans. This review summarizes the concepts and morphometric methods for studying asymmetry of shape and size. After a summary of mathematical and biological concepts of symmetry and asymmetry, a section follows that explains the methods of geometric morphometrics and how they can be used to analyze asymmetry of biological structures. Geometric morphometric analyses not only tell how much asymmetry there is, but also provide information about the patterns of covariation in the structure under study. Such patterns of covariation in fluctuating asymmetry can provide valuable insight about the developmental basis of morphological integration, and have become important tools for evolutionary developmental biology. The genetic basis of fluctuating asymmetry has been studied from empirical and theoretical viewpoints, but serious challenges remain in this area. There are many promising areas for further research that are only little explored at present.

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Section: Outline Methodsmentioning

confidence: 99%

Analyzing Fluctuating Asymmetry with Geometric Morphometrics: Concepts, Methods, and Applications

2015

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“…Landmarks allow to study shape variations via a configuration of clearly defined homologous points in 2D or 3D space (Bookstein, 1996;Webster and Sheets, 2010). Outline-based morphometric analyses, on the other hand, deal with open or closed curves or curve segments and largely neglect information from homologous points (Kuhl and Girdina, 1982;Lohmann, 1983;Haines and Crampton, 2000;Sheets et al, 2006). The majority of morphometric analyses of ostracods has 10 focused on outline methods (e.g., Danielopol et al, 2008;Tanaka, 2009;Namiotko et al, 2012;Gitter et al, 2015) mainly because of lacking homologous points in most non-marine taxa (Baltanas et al, 2002).…”

Section: Generalized Procrustes Analysismentioning

confidence: 99%

Impact of climate and hydrochemistry on shape variation – a case study on Neotropical cytheroidean Ostracoda

Wrozyna¹,

Neubauer²,

Meyer³

et al. 2017

Preprint

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Abstract. How environmental change affects a species' phenotype is crucial not only for taxonomy and biodiversity assessments but also for their application as (paleo-)ecological indicators. Previous investigations addressing the impact of climate and hydrochemical regime on ostracod valve morphology have yielded quite contrasting results. Frequently identified ecological factors influencing carapace shape are salinity, cation and sulphate concentrations and alkalinity. Here, we present a thorough approach integrating data from carapace outline and surface details of the ubiquitous Neotropical cytheroidean 15 ostracod species Cytheridella ilosvayi, as well as several climatic and hydrochemical variables, in order to investigate a potential link between morphology and environmental conditions. A previous study lately demonstrated considerable biogeographical variation in valve morphology among Floridian, Mexican and Brazilian populations of this species. We hypothesize that the climatic differences between the regions it inhabits and associated differences in hydrochemical regimes have influenced valve morphology and eventually led to biogeographically distinctive groups. Generalized least-squares 20Procrustes Analyses based on outline and structural features were applied to left and right valves of adult females and males.The analyses identified relative carapace length and shape symmetry as most important morphological characteristics representing shape change across all datasets. Two-block partial least-squares analyses and multiple regressions indicate strong relationships between morphological and environmental variables, specifically with temperature seasonality, annual precipitation and chloride and sulphate concentrations. We hypothesize that increased temperature seasonality slowed down 25 growth rates during colder months, potentially triggering the development of shortened valves with well-developed brood pouches. Differences in chloride and sulphate concentrations, related to fluctuations in precipitation, are considered to affect valve development via controlling osmoregulation and carapace calcification. These factors represent hitherto unknown drivers for ostracod ecophenotypy and emphasise that environmental predictors for morphological variability are not consistent across non-marine ostracods. 30Biogeosciences Discuss., https://doi

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“…Eigenshape analysis is a technique used for the reduction of digitized outline shapes into few parameters for multivariate analysis and visualization of shape variation (Lohman 1983, Ray 1992 Principal Components Analysis was performed in PAST ver. 2.02 (Hammer et al 2001) on covariance matrix of transformed coordinates using the Zahn-Roskies tangent function (Zahn & Roskies 1972).…”

Section: Data Acquisition and Sporangia Shape Analysismentioning

confidence: 99%

Geometric morphometry of Phytophthora plurivora sporangia

et al. 2015

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S., Diamandis S., Kostov K., 2015. Geometric morphometry of Phytophthora plurivora sporangia. Ann. For. Res. 58(2): 275-294.Abstract. Eigenshape analysis and Relative Warp Analysis were employed in the study of the shape of highly variable sporangia of Phytophthora plurivora, a widespread oomycetous pathogen isolated from woody species, in several South-East European countries: Bulgaria, Greece, Serbia and Romania. The aim of the study was to estimate whether shape variables permitted the quantitative assessment of sporangial shape variability in P. plurivora and also, the discrimination between species based solely on sporangial shape, P. cactorum being selected for comparisons. Both Eigenshape and Relative Warp Analyses showed that the most variable sporangial areas were apical and basal regions. More than half of the shape variation was accounted for the first 2 ES axes (66.75%) and first two RW axes (61.74%). ESA performed better in terms of species shape (P. plurivora and P. cactorum) separation. Canonical Variate Analysis/MANOVA and Discriminant Analysis indicated the clear discrimination between species and between isolates of P. plurivora. Mean or consensus shape performed as the best shape descriptor of sporangia. High dimensional variation considered in terms of centroid size corroborated with shape variation spanning from symmetrical consensus shape to conspicuously asymmetric shapes.

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Eigenshape analysis of microfossils: A general morphometric procedure for describing changes in shape

Cited by 207 publications

References 20 publications

Analyzing Fluctuating Asymmetry with Geometric Morphometrics: Concepts, Methods, and Applications

Analyzing Fluctuating Asymmetry with Geometric Morphometrics: Concepts, Methods, and Applications

Impact of climate and hydrochemistry on shape variation – a case study on Neotropical cytheroidean Ostracoda

Geometric morphometry of Phytophthora plurivora sporangia

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