Geometric morphometric analysis of fish scales for identifying genera, species, and local populations within the Mugilidae

2007 ◽  
Vol 64 (8) ◽  
pp. 1091-1100 ◽  
Author(s):  
Ana L Ibañez ◽  
Ian G Cowx ◽  
Paul O'Higgins
Keyword(s):  
Principal Component ◽  
Aegean Sea ◽  
Procrustes Analysis ◽  
Fish Scale ◽  
Genetic Studies ◽  
Geometric Morphometric ◽  
Geographically Dispersed ◽  
Geometric Morphometric Analysis ◽  
Components Analysis ◽  
Component Scores

Geometric morphometric methods (GMMs) were used to determine if scale morphology can discriminate between genera, species, geographic variants, and stocks of mullet (Mugilidae). GMMs were used because they allow standard multivariate analyses while preserving information about scale shape, which is important in making biological interpretations of results. The method was tested on ctenoid scales from mullets collected from different areas of the Gulf of Mexico and Aegean Sea. Scales were submitted to generalised procrustes analysis, followed by principal components analysis of resulting shape coordinates. Principal component scores were submitted to cross-validated discriminant analysis to determine the efficacy of scale landmarks in discriminating by taxon and population. Fish scale form was least effective in discriminating populations from nearby areas, better when populations are more geographically dispersed, and best between species and genera. Scale form variations reflected previous genetic studies that differentiated congeneric Mugil cephalus and Mugil curema, which are distinct from other Mugilidae. The method is nondestructive, quick, and less costly than genetic analysis, thus allowing many individuals to be screened.

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 Ecomorphometric analysis of diversity in cranial shape of pygopodid geckos

2021 ◽  
Author(s):  
George P Gurgis ◽  
Juan D Daza ◽  
Ian G Brennan ◽  
Mark Hutchinson ◽  
Aaron M Bauer ◽  
...  
Keyword(s):  
Small Sample Size ◽  
Taxonomic Diversity ◽  
Small Sample ◽  
Cranial Morphology ◽  
Level Variation ◽  
Generic Level ◽  
Geometric Morphometric ◽  
Geometric Morphometric Analysis ◽  
Components Analysis ◽  
Cranial Shape

Abstract Pygopodids are elongate, functionally limbless geckos found throughout Australia. The clade presents low taxonomic diversity (∼45 spp.), but a variety of cranial morphologies, habitat use, and locomotor abilities that vary between and within genera. In order to assess potential relationships between cranial morphology and ecology, CT scans of 29 species were used for 3D geometric morphometric analysis. A combination of 24 static landmarks and 20 sliding semi-landmarks were subjected to Generalized Procrustes Alignment. Disparity in cranial shape was visualized through Principal Components Analysis, and a MANOVA was used to test for an association between shape, habitat, and diet. A subset of 27 species with well-resolved phylogenetic relationships was used to generate a phylomorphospace and conduct phylogeny-corrected MANOVA. Similar analyses were done solely on Aprasia taxa to explore species-level variation. Most of the variation across pygopodids was described by PC1 (54%: cranial roof width, parabasisphenoid and occipital length), PC2 (12%: snout elongation and braincase width), and PC3 (6%: elongation and shape of the palate and rostrum). Without phylogenetic correction, both habitat and diet were significant influencers of variation in cranial morphology. However, in the phylogeny-corrected MANOVA, habitat remained weakly significant, but not diet, which can be explained by generic-level differences in ecology rather than among species. Our results demonstrate that at higher levels, phylogeny has a strong effect on morphology, but that influence may be due to small sample size when comparing genera. However, because some closely related taxa occupy distant regions of morphospace, diverging diets and use of fossorial habitats may contribute to variation seen in these geckos.

scholarly journals Inter- and intraspecific variation in grass phytolith shape and size: a geometric morphometrics perspective

2020 ◽  
Author(s):  
Kristýna Hošková ◽  
Adéla Pokorná ◽  
Jiří Neustupa ◽  
Petr Pokorný
Keyword(s):  
Intraspecific Variation ◽  
Methodological Approach ◽  
Principal Component ◽  
Interspecific Variation ◽  
Procrustes Analysis ◽  
Grass Species ◽  
Species Discrimination ◽  
Geometric Morphometric ◽  
Linear Discriminant ◽  
Shape And Size

Abstract Background and Aims The relative contributions of inter- and intraspecific variation to phytolith shape and size have only been investigated in a limited number of studies. However, a detailed understanding of phytolith variation patterns among populations or even within a single plant specimen is of key importance for the correct taxonomic identification of grass taxa in fossil samples and for the reconstruction of vegetation and environmental conditions in the past. In this study, we used geometric morphometric analysis for the quantification of different sources of phytolith shape and size variation. Methods We used landmark-based geometric morphometric methods for the analysis of phytolith shapes in two extant grass species (Brachypodium pinnatum and B. sylvaticum). For each species, 1200 phytoliths were analysed from 12 leaves originating from six plants growing in three populations. Phytolith shape and size data were subjected to multivariate Procrustes analysis of variance (ANOVA), multivariate regression, principal component analysis and linear discriminant analysis. Key Results Interspecific variation largely outweighed intraspecific variation with respect to phytolith shape. Individual phytolith shapes were classified with 83 % accuracy into their respective species. Conversely, variation in phytolith shapes within species but among populations, possibly related to environmental heterogeneity, was comparatively low. Conclusions Our results imply that phytolith shape relatively closely corresponds to the taxonomic identity of closely related grass species. Moreover, our methodological approach, applied here in phytolith analysis for the first time, enabled the quantification and separation of variation that is not related to species discrimination. Our findings strengthen the role of grass phytoliths in the reconstruction of past vegetation dynamics.

Metatarsal Shape and Foot Type: A Geometric Morphometric Analysis

2017 ◽  
Vol 139 (3) ◽  
Author(s):  
Scott Telfer ◽  
Matthew W. Kindig ◽  
Bruce J. Sangeorzan ◽  
William R. Ledoux
Keyword(s):  
Morphometric Analysis ◽  
Morphological Characteristics ◽  
Procrustes Analysis ◽  
Cross Sectional ◽  
Pes Cavus ◽  
Pes Planus ◽  
Geometric Morphometric ◽  
Metatarsal Bones ◽  
Increased Risk ◽  
Geometric Morphometric Analysis

Planus and cavus foot types have been associated with an increased risk of pain and disability. Improving our understanding of the geometric differences between bones in different foot types may provide insights into injury risk profiles and have implications for the design of musculoskeletal and finite-element models. In this study, we performed a geometric morphometric analysis on the geometry of metatarsal bones from 65 feet, segmented from computed tomography (CT) scans. These were categorized into four foot types: pes cavus, neutrally aligned, asymptomatic pes planus, and symptomatic pes planus. Generalized procrustes analysis (GPA) followed by permutation tests was used to determine significant shape differences associated with foot type and sex, and principal component analysis was used to find the modes of variation for each metatarsal. Significant shape differences were found between foot types for all the metatarsals (p < 0.01), most notably in the case of the second metatarsal which showed significant pairwise differences across all the foot types. Analysis of the principal components of variation showed pes cavus bones to have reduced cross-sectional areas in the sagittal and frontal planes. The first (p = 0.02) and fourth metatarsals (p = 0.003) were found to have significant sex-based differences, with first metatarsals from females shown to have reduced width, and fourth metatarsals from females shown to have reduced frontal and sagittal plane cross-sectional areas. Overall, these findings suggest that metatarsal bones have distinct morphological characteristics that are associated with foot type and sex, with implications for our understanding of anatomy and numerical modeling of the foot.

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.

Discrimination of the species of the Crassiphycus corneus/C. usneoides complex (Gracilariaceae, Rhodophyta) through geometric morphometric analysis

Nova Hedwigia ◽  
2019 ◽  
Vol 109 (3) ◽  
pp. 291-301 ◽  
Author(s):  
Martha Isabel Vilchis ◽  
Jiri Neustupa ◽  
Kurt Dreckmann ◽  
Alejandra Quintanar ◽  
Abel Sentíes
Keyword(s):  
Principal Component Analysis ◽  
Morphometric Analysis ◽  
Principal Component ◽  
Fourier Descriptors ◽  
Cortical Cells ◽  
Geometric Morphometric ◽  
Phenotypic Differences ◽  
Geometric Morphometric Analysis ◽  
Elliptic Fourier Descriptors ◽  
Manova Analysis

The results of the discrimination by geometric morphometry of the species within the Crassiphycus corneus/C. usneoides complex is presented, from the shape of its cortical, subcortical and medullary cells in the apical, medium and basal portions of thallus. Principal component analysis, based on the elliptic Fourier descriptors of cellular outline shapes and NP-MANOVA analysis, show that only the cortical cells in the medium portion were significantly wider in C. corneus than in C. usneoides. The isoperimetric quotients (Q) indicated that these cells were significantly more circular in C. corneus than in C. usneoides. We conclude that the outline analyses efficiently recovered phenotypic differences between the species defined by molecular systematics and considered to be cryptic, so far.

scholarly journals Craniofacial shape in patients with beta thalassaemia: a geometric morphometric analysis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Petros Roussos ◽  
Anastasia Mitsea ◽  
Demetrios Halazonetis ◽  
Iosif Sifakakis
Keyword(s):  
Principal Component ◽  
Cranial Base ◽  
Control Group ◽  
Geometric Morphometric ◽  
Beta Thalassaemia ◽  
Mandibular Body ◽  
Geometric Morphometric Analysis ◽  
And Gender ◽  
Maxilla And Mandible ◽  
Craniofacial Complex

AbstractThe shape of the craniofacial complex of patients with beta thalassaemia was evaluated using geometric morphometrics on lateral cephalometric radiographs and was compared with matched controls. The beta thalassaemia group consisted of 40 patients (16 females, 24 males, mean age 33.4). Each patient was matched by age and gender to two controls (32 females, 48 males, mean age 33.1). The 120 lateral cephalometric radiographs were digitized and traced with 15 curves, 10 landmarks and 117 sliding semi-landmarks. These landmarks were subjected to Procrustes superimposition and principal component analysis in order to describe shape variability of the cranial base, maxilla and mandible, as well as of the entire craniofacial complex for each sex. The first 4 principal components accounted for 50% of the total sample’s variability. The beta thalassaemia group was significantly different in overall shape to the control group for both sexes. Similar findings were noted for the maxilla, the mandible and the cranial base. The main differences were related to smaller mandibular body for the thalassaemia group, midface protrusion and decrease in posterior face height. The shape of the craniofacial complex in these patients is prone to be more convex and hyperdivergent.

Discrimination of American lobster (Homarus americanus) stocks off southern New England on the basis of secondary sex character allometry

1995 ◽  
Vol 52 (12) ◽  
pp. 2712-2723 ◽  
Author(s):  
Steven X. Cadrin
Keyword(s):  
New England ◽  
Principal Components ◽  
Principal Component ◽  
Homarus Americanus ◽  
American Lobster ◽  
Multiple Group ◽  
Southern New England ◽  
Female Data ◽  
Components Analysis ◽  
Component Scores

Male American lobster (Homarus americanus) from inshore southern New England were discriminated from offshore males on the basis of larger relative chela size. Lobsters from Buzzards Bay (inshore) had more conspicuous sexual dimorphism than lobsters from Hydrographer Canyon (offshore), and allometric growth of male chelae was more prominent than that of female abdomens. Principal components analysis of males from combined stocks represented variability in multivariate size and relative chela size, and component score distributions of each stock were discrete. Principal components of females from both stocks comprised variability in overall size and relative abdomen size, but principal component scores overlapped extensively. Multiple-group principal component 2 was a size-free index of relative chela size that classified 96% of males to the correct stock. Multiple-group principal component 2 of females did not successfully separate stocks. Discriminant analysis of size-adjusted morphometric data classified males to stock with 100% accuracy on the basis of relative chela size. Although discrimination of size-adjusted female data classified stocks with 94% accuracy, it was less stable and not associated with onset of maturity.

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.

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