Is formalin fixation and ethanol preservation able to influence in geometric morphometric analysis? Fishes as a case study

Zoomorphology ◽  
2012 ◽  
Vol 132 (1) ◽  
pp. 87-93 ◽  
Author(s):  
Pablo A. Martinez ◽  
Waldir M. Berbel-Filho ◽  
Uedson P. Jacobina
Keyword(s):  
Morphometric Analysis ◽  
Formalin Fixation ◽  
Geometric Morphometric ◽  
Geometric Morphometric Analysis

scholarly journals Geometric morphometric analysis of intratrackway variability: A case study on theropod and ornithopod dinosaur trackways from Münchehagen (Lower Cretaceous, Germany)

2016 ◽  
Author(s):  
Jens N Lallensack ◽  
Anneke H van Heteren ◽  
Oliver Wings
Keyword(s):  
Morphometric Analysis ◽  
Lower Cretaceous ◽  
Principal Component ◽  
Lower Saxony ◽  
Geometric Morphometric ◽  
Variable Regions ◽  
Substrate Properties ◽  
Geometric Morphometric Analysis ◽  
Left And Right

A profound understanding of the influence of trackmaker anatomy, foot movements and substrate properties is crucial for any interpretation of fossil tracks. In this case study we analyze variability of footprint shape within one large theropod (T3), one medium-sized theropod (T2) and one ornithopod (I1) trackway from the Lower Cretaceous of Münchehagen (Lower Saxony, Germany) in order to determine the informativeness of individual features and measurements for ichnotaxonomy, trackmaker identification, and the discrimination between left and right footprints. Landmark analysis is employed based on interpretative outline drawings derived from photogrammetric data, allowing for the location of variability within the footprint and the assessment of covariation of separate footprint parts. Objective methods to define the margins of a footprint are tested and shown to be sufficiently accurate to reproduce the most important results. The lateral hypex and the heel are the most variable regions in the two theropod trackways. As indicated by principal component analysis, a posterior shift of the lateral hypex is correlated with an anterior shift of the margin of the heel. This pattern is less pronounced in the ornithopod trackway, indicating that variation patterns can differ in separate trackways. In all trackways, hypices vary independently from each other, rendering their relative position a questionable feature for ichnotaxonomic purposes. Most criteria commonly employed to differentiate between left and right footprints assigned to theropods are found to be reasonably reliable. The described ornithopod footprints are asymmetrical, again allowing for a left-right differentiation. Strikingly, 12 out of 19 measured footprints of the T2 trackway are stepped over the trackway midline, rendering the trackway pattern a misleading left-right criterion for this trackway. Traditional measurements were unable to differentiate between the theropod and the ornithopod trackways. Geometric morphometric analysis reveals potential for improvement of existing discriminant methods.

scholarly journals Geometric morphometric analysis of intratrackway variability: A case study on theropod and ornithopod dinosaur trackways from Münchehagen (Lower Cretaceous, Germany)

2016 ◽  
Author(s):  
Jens N Lallensack ◽  
Anneke H van Heteren ◽  
Oliver Wings
Keyword(s):  
Morphometric Analysis ◽  
Lower Cretaceous ◽  
Principal Component ◽  
Lower Saxony ◽  
Geometric Morphometric ◽  
Variable Regions ◽  
Substrate Properties ◽  
Geometric Morphometric Analysis ◽  
Left And Right

A profound understanding of the influence of trackmaker anatomy, foot movements and substrate properties is crucial for any interpretation of fossil tracks. In this case study we analyze variability of footprint shape within one large theropod (T3), one medium-sized theropod (T2) and one ornithopod (I1) trackway from the Lower Cretaceous of Münchehagen (Lower Saxony, Germany) in order to determine the informativeness of individual features and measurements for ichnotaxonomy, trackmaker identification, and the discrimination between left and right footprints. Landmark analysis is employed based on interpretative outline drawings derived from photogrammetric data, allowing for the location of variability within the footprint and the assessment of covariation of separate footprint parts. Objective methods to define the margins of a footprint are tested and shown to be sufficiently accurate to reproduce the most important results. The lateral hypex and the heel are the most variable regions in the two theropod trackways. As indicated by principal component analysis, a posterior shift of the lateral hypex is correlated with an anterior shift of the margin of the heel. This pattern is less pronounced in the ornithopod trackway, indicating that variation patterns can differ in separate trackways. In all trackways, hypices vary independently from each other, rendering their relative position a questionable feature for ichnotaxonomic purposes. Most criteria commonly employed to differentiate between left and right footprints assigned to theropods are found to be reasonably reliable. The described ornithopod footprints are asymmetrical, again allowing for a left-right differentiation. Strikingly, 12 out of 19 measured footprints of the T2 trackway are stepped over the trackway midline, rendering the trackway pattern a misleading left-right criterion for this trackway. Traditional measurements were unable to differentiate between the theropod and the ornithopod trackways. Geometric morphometric analysis reveals potential for improvement of existing discriminant methods.

scholarly journals Geometric morphometric analysis of intratrackway variability: a case study on theropod and ornithopod dinosaur trackways from Münchehagen (Lower Cretaceous, Germany)

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2059 ◽  
Author(s):  
Jens N. Lallensack ◽  
Anneke H. van Heteren ◽  
Oliver Wings
Keyword(s):  
Morphometric Analysis ◽  
Lower Cretaceous ◽  
Principal Component ◽  
Lower Saxony ◽  
Geometric Morphometric ◽  
Variable Regions ◽  
Substrate Properties ◽  
Geometric Morphometric Analysis ◽  
Left And Right

A profound understanding of the influence of trackmaker anatomy, foot movements and substrate properties is crucial for any interpretation of fossil tracks. In this case study we analyze variability of footprint shape within one large theropod (T3), one medium-sized theropod (T2) and one ornithopod (I1) trackway from the Lower Cretaceous of Münchehagen (Lower Saxony, Germany) in order to determine the informativeness of individual features and measurements for ichnotaxonomy, trackmaker identification, and the discrimination between left and right footprints. Landmark analysis is employed based on interpretative outline drawings derived from photogrammetric data, allowing for the location of variability within the footprint and the assessment of covariation of separate footprint parts. Objective methods to define the margins of a footprint are tested and shown to be sufficiently accurate to reproduce the most important results. The lateral hypex and the heel are the most variable regions in the two theropod trackways. As indicated by principal component analysis, a posterior shift of the lateral hypex is correlated with an anterior shift of the margin of the heel. This pattern is less pronounced in the ornithopod trackway, indicating that variation patterns can differ in separate trackways. In all trackways, hypices vary independently from each other, suggesting that their relative position a questionable feature for ichnotaxonomic purposes. Most criteria commonly employed to differentiate between left and right footprints assigned to theropods are found to be reasonably reliable. The described ornithopod footprints are asymmetrical, again allowing for a left–right differentiation. Strikingly, 12 out of 19 measured footprints of the T2 trackway are stepped over the trackway midline, rendering the trackway pattern a misleading left–right criterion for this trackway. Traditional measurements were unable to differentiate between the theropod and the ornithopod trackways. Geometric morphometric analysis reveals potential for improvement of existing discriminant methods.

scholarly journals Vector-GMA: A New Easy Method for Analyzing Morphometric Data

2021 ◽  
Author(s):  
Dmitry S. Kopylov
Keyword(s):  
Morphometric Analysis ◽  
Morphological Features ◽  
New Method ◽  
Morphometric Data ◽  
Easy Method ◽  
Geometric Morphometric ◽  
Articulated Structures ◽  
Geometric Morphometric Analysis

Abstract The new method of geometric morphometric analysis, called Vector-GMA is proposed. Unlike the classic TPS-based GMA, the new method allows considering missing and inapplicable landmarks and analyzing articulated structures. It also contains a set of tools for analyzing particular morphological features and searching for promising identification characters. The results of the analysis can be easily converted into phylogenetic matrix and analyzed with phylogenetic software. For the case study, the fore wings of all Cretaceous ichneumonids are analyzed.

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