Comparing and combining sliding semilandmarks and weighted spherical harmonics for shape analysis

Harper, Christine M.; Goldstein, Deanna M.; Sylvester, Adam D.

doi:10.1111/joa.13589

Cited by 11 publications

(29 citation statements)

References 32 publications

(61 reference statements)

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“…The more coefficients that a SPHARM model contains, the more accurate the 1D object's reconstruction will be (Shen et al, 2009). When objects are aligned to (i.e., registered to) the same template specimen, registered SPHARM models can be used to create a set of surface models with geometrically homologous vertices (similar to the output of a sliding semilandmark analysis) (Harper, Goldstein, & Sylvester, 2021; Shen et al, 2009).…”

Section: Methodsmentioning

confidence: 99%

Carpal allometry of African apes among mammals

Goldstein

Sylvester

2023

American Journal of Biological Anthropology

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Objectives Morphological variation in African ape carpals has been used to support the idea that Pan and Gorilla evolved knuckle‐walking independently. Little work, however, has focused on the effect of body mass on carpal morphology. Here, we compare carpal allometry in Pan and Gorilla to that of other quadrupedal mammals with similar body mass differences. If allometric trends in Pan and Gorilla carpals mirror those of other mammals with similar body mass variation, then body mass differences may provide a more parsimonious explanation for African ape carpal variation than the independent evolution of knuckle‐walking. Materials and Methods Three linear measurements were collected on the capitate, hamate, lunate, and scaphoid (or scapholunate) of 39 quadrupedal species from six mammalian families/subfamilies. Relationships between linear measurements and estimated body mass were analyzed using reduced major axis regression. Slopes were compared to 0.33 for isometry. Results Within Hominidae, higher body mass taxa (Gorilla) have relatively anteroposteriorly wider, mediolaterally wider, and/or proximodistally shorter capitates, hamates, and scaphoids than low body mass taxa (Pan). These allometric relationships are mirrored in most, but not all, mammalian families/subfamilies included in the analysis. Conclusions Within most mammalian families/subfamilies, carpals of high body mass taxa are proximodistally shorter, anteroposteriorly wider, and mediolaterally wider than those of low body mass taxa. These distinctions may be caused by the need to accommodate relatively higher forelimb loading associated with greater body mass. Because these trends occur within multiple mammalian families/subfamilies, some carpal variation in Pan and Gorilla is consistent with body mass differences.

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Section: Methodsmentioning

confidence: 99%

Carpal allometry of African apes among mammals

Goldstein

Sylvester

2023

American Journal of Biological Anthropology

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“…A SPHARM analysis was chosen because the talus is a difficult bone to carry out a whole‐bone three‐dimensional (3D) sliding semilandmark analysis on due to its complex morphology and lack of well‐defined locations to place Type I landmarks (defined as points at discrete juxtapositions of tissues; Bookstein, 1991). Weighted spherical harmonics is a landmark‐free 3D whole‐bone method of shape analysis that is suitable for the analysis of small, irregularly shaped bones (such as the talus) that lack features for the obvious placement of landmarks (Harper et al, 2022; Shen et al, 2009). It has previously been used by neuroscientists to quantify brain shapes (Gerig et al, 2001; Goldberg‐Zimring et al, 2005), biologists to study insect reproductive structures (Shen et al, 2009), and more recently in biological anthropology to study Eocene euprimate tarsals (Llera Martín et al, 2022).…”

Section: Methodsmentioning

confidence: 99%

“…It has previously been used by neuroscientists to quantify brain shapes (Gerig et al, 2001;Goldberg-Zimring et al, 2005), biologists to study insect reproductive structures (Shen et al, 2009), and more recently in biological anthropology to study Eocene euprimate tarsals (Llera Martín et al, 2022). The equivalency of SPHARM and 3D sliding semilandmarks for shape analysis has been previously established (Harper et al, 2022).…”

Section: Weighted Spherical Harmonic Analysismentioning

confidence: 99%

“…This statistic was calculated in MATLAB 2019a (MathWorks Inc., 2019). Root mean square distances were chosen as the distance metric for this analysis because it is the metric used by the SPHARM software to minimize the distance between the coefficients of the specimen of interest and the template specimen during the registration step (Gerig et al, 2001;Harper et al, 2022;Shen et al, 2009). Pan taxa (Figure 3).…”

Section: Statistical Analysesmentioning

confidence: 99%

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Morphological variation of the Pan talus relative to that of Gorilla

Harper,

Roach,

Goldstein

et al. 2023

American Journal of Biological Anthropology

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Objectives Differences in talar articular morphology relative to locomotion have recently been found within Pan and Gorilla. Whole‐bone talar morphology within, and shared variation among, Pan and Gorilla (sub)species, however, has yet to be investigated. Here we separately analyze talar external shape within Pan (P. t. troglodytes, P. t. schweinfurthii, P. t. verus, P. paniscus) and Gorilla (G. g. gorilla, G. b. beringei, G. b. graueri) relative to degree of arboreality and body size. Pan and Gorilla are additionally analyzed together to determine if consistent shape differences exist within the genera. Materials and Methods Talar external shape was quantified using a weighted spherical harmonic analysis. Shape variation both within and among Pan and Gorilla was described using principal component analyses. Root mean square distances were calculated between taxon averages, and resampling statistics conducted to test for pairwise differences. Results P. t. verus (most arboreal Pan) talar shape significantly differs from other Pan taxa (p < 0.05 for pairwise comparisons) driven by more asymmetrical trochlear rims and a medially‐set talar head. P. t. troglodytes, P. t. schweinfurthii, and P. paniscus do not significantly differ (p > 0.05 for pairwise comparisons). All gorilla taxa exhibit significantly different talar morphologies (p < 0.007 for pairwise comparisons). The more terrestrial subspecies of G. beringei and P. troglodytes exhibit a superoinferiorly taller talar head/neck complex. Discussion P. t. verus exhibits talar morphologies that have been previously related to more frequent arboreality. The adaptations in the more terrestrial G. beringei and P. troglodytes subspecies may serve to facilitate load transmission.

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“…A few previous studies have attempted to assess the performance of different semilandmarking approaches. Evaluated criteria for comparing different semilandmarking approaches include: the Euclidean distances between semilandmarks (or landmarks) from each approach or with manually placed ones [ 34 ]; comparison between methods of the resulting distributions of groups [ 10 , 26 , 35 ]; the geometric deviation between template and transformed meshes [ 10 , 19 ]; the first two principal components (PCs) [ 26 , 35 , 36 ]; distance matrices to quantify shape variations [ 25 , 26 , 31 , 36 ]; and estimates of centroid size of resulting configurations [ 34 ]. These criteria may indicate how different semilandmarking strategies perform in matching surfaces, distinguishing groups, or identifying unknown specimens, but they do not relate to how well the homology map is represented by the resulting semilandmarks.…”

Section: Introductionmentioning

confidence: 99%

A Comparison of Semilandmarking Approaches in the Analysis of Size and Shape

Shui

Profico

O’Higgins

2023

Animals

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Often, few landmarks can be reliably identified in analyses of form variation and covariation. Thus, ‘semilandmarking’ algorithms have increasingly been applied to surfaces and curves. However, the locations of semilandmarks depend on the investigator’s choice of algorithm and their density. In consequence, to the extent that different semilandmarking approaches and densities result in different locations of semilandmarks, they can be expected to yield different results concerning patterns of variation and co-variation. The extent of such differences due to methodology is, as yet, unclear and often ignored. In this study, the performance of three landmark-driven semilandmarking approaches is assessed, using two different surface mesh datasets (ape crania and human heads) with different degrees of variation and complexity, by comparing the results of morphometric analyses. These approaches produce different semilandmark locations, which, in turn, lead to differences in statistical results, although the non-rigid semilandmarking approaches are consistent. Morphometric analyses using semilandmarks must be interpreted with due caution, recognising that error is inevitable and that results are approximations. Further work is needed to investigate the effects of using different landmark and semilandmark templates and to understand the limitations and advantages of different semilandmarking approaches.

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Comparing and combining sliding semilandmarks and weighted spherical harmonics for shape analysis

Cited by 11 publications

References 32 publications

Carpal allometry of African apes among mammals

Carpal allometry of African apes among mammals

Morphological variation of the Pan talus relative to that of Gorilla

A Comparison of Semilandmarking Approaches in the Analysis of Size and Shape

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