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 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 A new species of Prosyntexis Sharkey, 1990 (Hymenoptera: Sepulcidae) from the Lower Cretaceous Crato Formation of Brazil confirmed by geometric morphometric analysis

2021 ◽  
Vol 4 (2) ◽  
pp. 171-177
Author(s):  
CORENTIN JOUAULT ◽  
ANDRÉ NEL
Keyword(s):  
New Species ◽  
Morphometric Analysis ◽  
Lower Cretaceous ◽  
The Other ◽  
New Taxon ◽  
Additional Specimen ◽  
Geometric Morphometric ◽  
Geometric Morphometric Analysis ◽  
A New Species

Examination of new fossil specimens of Prosyntexis from the Lower Cretaceous Crato Formation of Brazil reveled a new species namely Prosyntexis sennlaubi sp. nov. To ensure the validity of the new taxon we examined previously described and figured specimens but we also figured an additional specimen of Prosyntexis gouleti Sharkey, 1990. The new species can be differentiated from the other Prosyntexis species of the Crato formation by its larger size but also in having the cell 2R1 small, the cell 2M small and short, the cell 3R1 narrow and the vein a directed toward wing apex. We performed a Geometric Morphometric Analysis (GMA) to estimate the variation in the forewing venation of the two species from the Crato Formation and ensure our placement.

Geometric morphometric analysis applied to theropod tracks from the Lower Cretaceous (Berriasian) of Spain

Palaeontology ◽  
2014 ◽  
Vol 58 (1) ◽  
pp. 183-200 ◽  
Author(s):  
Diego Castanera ◽  
Jorge Colmenar ◽  
Víctor Sauqué ◽  
José I. Canudo
Keyword(s):  
Morphometric Analysis ◽  
Lower Cretaceous ◽  
Geometric Morphometric ◽  
Geometric Morphometric Analysis ◽  
Theropod Tracks

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.

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