Novelty and “Homology-free” Morphometrics: What’s in a Name?

Klingenberg, Christian Peter

doi:10.1007/s11692-008-9029-4

Cited by 88 publications

(81 citation statements)

References 25 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]. Different methods are making different assumptions about this correspondence or use it in different ways.…”

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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“…Metapophyses and anapophyses and their corresponding linear and angular measures are, with some exception, specific to the xenarthrous region, and their influence on intervertebral mechanics is the focus of the present study. To address the almost total lack of metapophyses and anapophyses in pre-xenarthrous thoracic vertebrae, we followed the precedent set by Head and Polly (2015) and by Klingenberg (2008) in measuring the evolution of morphological novelty using homologous landmarks. Klingenberg (2008) suggested assigning landmarks to the fully formed structure of interest, and in its absence, to the position on the surface from which it would emerge.…”

Section: Morphological Measurementsmentioning

confidence: 99%

“…To address the almost total lack of metapophyses and anapophyses in pre-xenarthrous thoracic vertebrae, we followed the precedent set by Head and Polly (2015) and by Klingenberg (2008) in measuring the evolution of morphological novelty using homologous landmarks. Klingenberg (2008) suggested assigning landmarks to the fully formed structure of interest, and in its absence, to the position on the surface from which it would emerge. This method was coopted specifically for vertebrae by Head and Polly (2015), who were able to assign landmarks to vertebral morphologies not present in all measured vertebrae.…”

Section: Morphological Measurementsmentioning

confidence: 99%

Vertebral bending mechanics and xenarthrous morphology in the nine-banded armadillo (Dasypus novemcinctus)

Oliver

Jones

Hautier

et al. 2016

Journal of Experimental Biology

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The vertebral column has evolved to accommodate the broad range of locomotor pressures found across vertebrate lineages. Xenarthran (armadillos, sloths and anteaters) vertebral columns are characterized by xenarthrous articulations, novel intervertebral articulations located in the posterior trunk that are hypothesized to stiffen the vertebral column to facilitate digging. To determine the degree to which xenarthrous articulations impact vertebral movement, we passively measured compliance and range of motion during ventroflexion, dorsiflexion and lateral bending across the thoracolumbar region of the nine-banded armadillo, Dasypus novemcinctus. Patterns of bending were compared with changes in vertebral morphology along the column to determine which morphological features best predict intervertebral joint mechanics. We found that compliance was lower in post-diaphragmatic, xenarthrous vertebrae relative to pre-xenarthrous vertebrae in both sagittal and lateral planes of bending. However, we also found that range of motion was higher in this region. These changes in mechanics are correlated with the transition from pre-xenarthrous to xenarthrous vertebrae, as well as with the transition from thoracic to lumbar vertebrae. Our results thus substantiate the hypothesis that xenarthrous articulations stiffen the vertebral column. Additionally, our data suggest that xenarthrous articulations, and their associated enlarged metapophyses, also act to increase the range of motion of the post-diaphragmatic region. We propose that xenarthrous articulations perform the dual role of stiffening the vertebral column and increasing mobility, resulting in passively stable vertebrae that are capable of substantial bending under appropriate loads.

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“…Most of the research efforts in geometric morphometrics have concentrated on landmark data. Morphological landmarks are points that can be located precisely on each specimen under study with a clear correspondence in a one-to-one manner from specimen to specimen [7,21]. There are several methods for the analysis of curves and outlines.…”

Section: Geometric Morphometrics Methodologymentioning

confidence: 99%

Sexual Dimorphism Using Geometric Morphometric Approach

Benítez¹

2013

Sexual Dimorphism

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Novelty and “Homology-free” Morphometrics: What’s in a Name?

Cited by 88 publications

References 25 publications

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

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

Vertebral bending mechanics and xenarthrous morphology in the nine-banded armadillo (Dasypus novemcinctus)

Sexual Dimorphism Using Geometric Morphometric Approach

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