robert z selden jr, archaeology, archeology, geometric morphometric, ceramic, analysis, mathematics, statistics, 3d, 3d scan

Shape and Form

I have always been interested in the shape and form of prehistoric artifacts. When I began to explore applications of landmark geometric morphometrics in archaeology, I was interested in using the method to aid in the identification of specific analytical thresholds (i.e., possible to identify a maker/group of makers?). More recently, my efforts have become focused upon theoretical morphospace, which aggregates formal studies of shape, allowing analysts to better clarify changes issues of morphological change through time. It is within discussions of theoretical morphological transitions where I see the greatest promise for geometric morphometrics in archaeology; an ambit of inquiry in which the skeleton trees and topological properties of the artifacts tell us a much more dynamic story with regard to the progression of a particular shape (bottle, bowl, olla, etc.) through time.

PCA for Caddo compound bowls from the Vanderpool site.

As with any formal inquiry, this pursuit began with a formal study of the extant literature. Working alongside colleagues from Texas A&M University, the University of Southampton, and Aarhus University, we assembled a citation network that included the publications and cited references for geometric morphometric studies (archaeological applications) to better understand how each work articulated with one another.

Citation network for geometric morphometrics in archaeology.

Following the literature study, my work was further segmented into three general areas: landmark and semi-landmark application, analyses, and replicability (for my LM/sLM positions and scripts). With the permission of the Caddo Nation of Oklahoma, I began to collect 3D data for a large number of ceramics that articulated with the Native American Graves Protection and Repatriation Act (NAGPRA). During our discussions, we arrived at an agreement that 3D models of the NAGPRA vessels could be shared, provided the texture (color) data was not included. In some cases, the Caddo do provide permission to share the fully-textured models; however, those remain the exception and not the rule.


This information can be used to bolster our discussions of shape, form, allometry, and asymmetry in Caddo ceramic studies, and used to posit a number of novel insights into the highly variable and dynamic prehistoric landscape that the Caddo people commanded. Within the context of my own long-term research design, theoretical morphospace seemingly holds much promise and may represent the approach needed to identify, unlock, and unpack a morphological transition that remains hidden in the various vessel shapes and forms once employed by Caddo potters.