Geometric Morphometrics

Zooarchaeological Analysis of the Indigenous Fishery at the Huu7ii Big House and Back Terrace, Huu-ay-aht Territory, Southwestern Vancouver Island

by Iain McKechnie

(2012) Zooarchaeological Analysis of the Indigenous Fishery at the Huu7ii Big House and Back Terrace, Huu-ay-aht Territory, Southwestern Vancouver Island. In Huu7ii: Household Archaeology at a Nuu-chah-nulth Village Site in Barkley Sound, by Alan D. McMillan and Denis E. St. Claire. Archaeology Press, Simon Fraser University, Burnaby, BC.

This paper describes how fish overwhelmingly dominates the animal bone assemblage from the examined column sample... more This paper describes how fish overwhelmingly dominates the animal bone assemblage from the examined column sample deposits at the Huu7ii village site, the named ancestral village of the Huu-ay-aht First Nation. Fish represent 99.9% of all identified bone specimens and are present in every examined litre of sediment indicating the importance of fish in the everyday life of site occupants. The bone assemblage is numerically dominated by Pacific herring, which vastly outnumbers the next most abundant fish: anchovy, salmon, hake, greenling, dogfish, and rockfish as well as two-dozen other fish taxa. I conduct a series of descriptive, quantitative, and graphical analyses that seek to interpret resource harvesting practices at the two examined portions of the site: a very large house (17x35m) dating to the late-Holocene (ca. 1,500-400 yr BP) and mid-Holocene midden deposits recovered on a raised beach terrace (ca. 5,000-3,000 yr BP).

Morphology of the Distal Radius in Extant Hominoids and Fossil Hominins: Implications for the Evolution of Bipedalism

by Melissa Tallman

One of the long-standing arguments about the evolution of bipedality centers on the locomotor pattern used by the last... more One of the long-standing arguments about the evolution of bipedality centers on the locomotor pattern used by the last common ancestor (LCA) of apes and humans. In particular, knuckle-walking has been suggested as this locomotor pattern on the basis of shared morphology in the upper limb between African apes and humans and phylogenetic parsimony. Using three-dimensional geometric morphometrics, this study tests whether the distal radius of extant hominoids is sufficient for determining locomotor pattern and the affiliations of Plio-Pleistocene hominins to the extant taxa. Results indicate that while the entire radius differentiates the extant taxa very well by locomotor pattern, the distal radius fails to clearly differentiate the extant taxa. The sigmoid notch of the distal radius is the anatomical feature that differs most among the extant taxa, and its variability broadly correlates with necessary mobility at the wrist joint. Principal components and discriminant function analyses indicate that early hominins are affiliated with a variety of extant taxa with different locomotor patterns. Overall, the bony anatomy of the distal radius of early hominins points towards something adapted for a wide variety of locomotor postures.

SKULL SHAPE AND SIZE DIVERGENCE IN DOLPHINS OF THE GENUS SOTALIA: A TRIDIMENSIONAL MORPHOMETRIC ANALYSIS

by Leandro Monteiro

Morphological divergence rate tests for natural selection: uncertainty of parameter estimation and robustness of results

by Leandro Monteiro

Multivariate Regression Models and Geometric Morphometrics: The Search for Causal Factors in the Analysis of Shape

by Leandro Monteiro

GEOMETRIC ESTIMATES OF HERITABILITY IN BIOLOGICAL SHAPE

by Leandro Monteiro

Distances and Directions in Multidimensional Shape Spaces: Implications for Morphometric Applications

by Leandro Monteiro

Shape distances, shape spaces and the comparison of morphometric methods

by Leandro Monteiro

SHAPE DISTANCES IN GENERAL LINEAR MODELS: ARE THEY REALLY AT ODDS WITH THE GOALS OF MORPHOMETRICS? A REPLY TO KLINGENBERG

by Leandro Monteiro

Evolutionary integration and morphological diversification in complex morphological structures: mandible shape divergence in spiny rats (Rodentia, Echimyidae)

by Leandro Monteiro

Morphological divergence patterns among populations of Poecilia vivipara (Teleostei Poeciliidae): test of an ecomorphological paradigm: MORPHOLOGICAL DIVERGENCE AND ECOMORPHOLOGY

by Leandro Monteiro

Morphological correlates of bite force and diet in the skull and mandible of phyllostomid bats

by Leandro Monteiro

Evolutionary patterns and processes in the radiation of phyllostomid bats

by Leandro Monteiro

Adaptive radiations, ecological specialization, and the evolutionary integration of complex morphological structures

by Leandro Monteiro

Monteiro, L. R., L.H. Guillermo, L. A. Rivera, and A. P. M. Di Beneditto. (2004) Geometric methods combining contour and landmark information in the statistical analysis of biological shape. In Proceedings of the Third Brazilian Symposium on Mathematical and Computational Biology, edited by Mondaini, R. Vol. 2, 336-355. Rio de Janeiro: E-papers

by Leandro Monteiro

Monteiro, L. R., L. H. Guillermo, and L. A. Rivera. (2003) Shape Spaces, Metrics and Linear Models for Evolutionary Rates. In Proceedings of the Second Brazilian Symposium on Mathematical and Computational Biology, edited by Mondaini, R. Vol. 1, 179-207. Rio de Janeiro: E-Papers.

by Leandro Monteiro

Modeling the human mandible under masticatory loads: which input variables are important?

by Flora Gröning

2012, Anatomical Record, DOI: 10.1002/ar.22455

Finite element analyses (FEA) that have simulated masticatory loadings of the human mandible differ significantly with... more Finite element analyses (FEA) that have simulated masticatory loadings of the human mandible differ significantly with regard to their basic input variables such as material properties, constraints, and applied forces. With sensitivity analyses it is possible to assess how the choice of different input values and the degree of model simplification affect FEA results. However, published FEA studies are rarely accompanied by sensitivity analyses so that the robusticity of their results is impossible to assess. Here, we conduct a sensitivity analysis with an FE model of a human mandible to quantify the relative importance of several modeling decisions: (1) the material properties assigned to the cancellous bone tissue; (2) the inclusion or not of the periodontal ligament; (3) the constraints at the joints and bite point; and (4) the orientation of applied muscle forces. We study the effects of varying these properties by analysing the strain magnitudes and directions across the model surface. In addition, we perform a geometric morphometric analysis of the deformation resulting from the loading of each model. The results show that the effects of altering the different model properties can be significant and that most effects are potentially large enough to cause problems for the biological interpretation of FEA results. We therefore recommend that researchers conduct more sensitivity analyses than at present to assess the robusticity of their FEA results and their biological conclusions.

Virtual functional morphology: novel approaches to the study of craniofacial form and function

by Flora Gröning

2012, Evolutionary Biology, DOI: 10.1007/s11692-012-9173-8

Recent developments in simulating musculoskeletal functioning in the craniofacial complex using multibody dynamic... more Recent developments in simulating musculoskeletal functioning in the craniofacial complex using multibody dynamic analysis and finite elements analysis enable comprehensive virtual investigations into musculoskeletal form and function. Because the growth of the craniofacial skeleton is strongly influenced by mechanical functioning, these methods have potential in investigating the normal and abnormal development of the skull: loading history during development can be predicted and bony adaptations to these loads simulated. Thus these methods can be used to predict the impact of altered loading or modifications of skull form early in ontogeny on the subsequent development of structures. Combining functional models with geometric morphometric methods (GMM), which are principally concerned with the study of variations of form, offers the opportunity to examine variations in form during development and the covariations between form and factors such as functional performance. Such a combination of functional models and GMM can potentially be applied in many useful ways, for example: to build and modify functional models, to assess the outcomes of remodelling studies by comparing the results with morphological changes during ontogeny, and to compare the outcomes of finite element analyses within a multivariate framework. Studies using these tools can not only investigate the development of the skull but also the mechanical processes and thus to some degree, behaviours underlying the development of variation among extant and fossil skeletal elements. By bringing together these tools from quite different comparative traditions, a novel and potentially powerful framework for simulation and statistical biomechanical analyses of form and function emerges. This paper reviews these recent developments in the context of the evolutionary and functional influences on skull development.

Inferring paleoecology in extinct tremarctine bears (Carnivora, Ursidae) via geometric morphometrics.

by Leopoldo Soibelzon

In this study, we explore the ecomorphological patterns of extinct tremarctine bears in
South America during the... more In this study, we explore the ecomorphological patterns of extinct tremarctine bears in
South America during the Great American Biotic Interchange (GABI). These patterns
are used to derive paleoautoecological inferences in extinct tremarctines and their
paleosinecological relationships within Plio-Pleistocene ecosystems. We used geometric
morphometrics of landmark data to recover the shape of the craniomandibular skeleton
of bears. The results reveal different ecomorphological adaptations in extinct
tremarctines during the Plio-Pleistocene of South America. Indeed, these bears could
have increased the percentage of plant matter in their diets accordance with the
increased diversity of large carnivores in South America after the GABI. Omnivorous
bears retain the ability to behave as carnivores or herbivores depending on resource
availability. This fact strongly supports that living and extinct bears are one of the most
ecologically and morphologically adaptable members of the large carnivore guild.
Moreover, their skull morphology could reflect ecological adaptations under different
selection pressures with the required evolutionary time.

Phylogeny and Evolution of the Mecochiridae (Decapoda: Reptantia: Glypheoidea): An Integrated Morphometric and Cladistic Approach

by Tim Astrop

Journal of Crustacean Biology 31(1):114-125. 2011
doi: 10.1651/10-3307.1

This study provides a systematic and phylogenetic overview of the extinct reptant decapod family Mecochiridae.... more This study provides a systematic and phylogenetic overview of the extinct reptant decapod family Mecochiridae. Mecochiridae are distinguished from both their traditional out-groups, Glypheidae and Erymidae, using cladistic and geometric morphometric techniques. Cladistic analysis of 12 species using 21 traditional and new characters verifies the in-group genera Mecochirus and Pseudoglyphea. Glyphea emerges as a sister group to Pseudoglyphea, suggesting a re-assignment of the genus to Glypheidae. The genus Meyeria is recovered as paraphyletic, suggesting the establishment of a new taxonomic group for species of Meyeria that exhibit a posterior tuberculated ridge, a well-developed hepatic bulge or ridge, and unornamented pleura. Both relative warp and Eigenshape analysis of the carapace and groove patterns that have long been used as descriptive morphological features succeeded in highlighting modes of shape change that when subjected to a discriminant analysis proved useful in distinguishing members of Mecochiridae. This study shows that landmark geometric morphometric methods and eigenshape analysis can be used to investigate the fidelity of existing taxonomic groupings based on other methods, and that an integrated cladistic and morphometric methodology has the potential to aid in resolving relationships among other unknown or problematic fossil taxa.