geometric morphometrics, asymmetry, 3d, archaeology, Caddo, ceramic, pottery, analysis, deviation, 3d scan, 3d model

New Publication in  DAACH

https://doi.org/10.1016/j.daach.2017.04.003

While pursuing a study of 3D geometric morphometrics for ceramic burial vessels that often articulate with the Native American Graves Protection and Repatriation Act (NAGPRA) from the ancestral Caddo region, there have been no shortage of potentially meaningful observations, one of which–rotational asymmetry in coil-built vessels–is discussed in this publication. Using Geomagic Design X (reverse-engineering software) and Geomagic Control X (computer aided inspection software), metrics associated with rotational asymmetry were generated then analyzed.

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Vessels can be sectioned, where the deviations for a specific spline can be extracted for a more in-depth analysis.

Results indicate variable asymmetry among the different vessel shapes (i.e., bottles, jars, etc.), which may augment and strengthen studies and discussions of vessel form. Future directions include the incorporation of directional and–possibly–fluctuating asymmetry measures for the widest vessel profiles. Preliminary results point toward substantive analytical gains that can be used to augment more traditional ceramic analyses as well as geometric morphometric studies of ceramic vessel shape.

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Results of the asymmetry analysis.

In addition to the analysis of rotational asymmetry, there is a brief discussion for analyses of (directional and fluctuating) asymmetry using geometric morphometrics. While the bulk of that discussion remains the topic of another paper, the citation network for asymmetry studies that use geometric morphometrics was included in this paper, and can be accessed by clicking on the image or the link below.

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Directed bipartite citation network for studies of asymmetry using geometric morphometrics. Access the network here.

Link to the publication here, and view the 3D models of the Caddo vessels from the Washington Square Mound site here.  Links to the digital repository where you can download these data are included in the publication.

Many thanks to the Caddo Nation of Oklahoma for the requisite permissions needed to scan the vessels, and to the Anthropology and Archaeology Laboratory for access. 

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Caddo Bottle from 16Sa37 in Northwest Louisiana

This Caddo bottle comes from 16Sa37 in Northwest Louisiana, is curated at the Texas Archeological Research Laboratory in Austin, Texas, and was scanned with a GoSCAN20. This vessel will be integrated into our study of Caddo vessel morphology, and these data will be made available through a data paper. Additionally, these scans will eventually be included in the Texas Archeological Society Newsletter, as we received generous funding from the Texas Archeological Society to create the scans.

In addition to those attributes associated with vessel shape, form, allometry and asymmetry, the standard suite of Caddo vessel attributes (sensu Perttula) will be included as we continue our effort to synthesize and examine macro-level trends in the Southern Caddo Area.

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New publications in the Journal of Texas Archeology and History

The first two peer-reviewed data papers have just been published in the Journal of Texas Archeology and History, detailing the hardware, software and methods used to generate these two important datasets. This helps to keep the data collection process transparent, and ensures that we are following best practices in terms of data collection, processing and digital curation. These data papers are open access; simply click on the image of the cover page to be transferred to each.

Many thanks to the Caddo Nation of Oklahoma, Texas Archeological Research Laboratory and the Texas Parks and Wildlife Department for the requisite permissions and access needed to generate the scans.

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3D Effigy Vessel from the Belcher Mound Site in NW Louisiana

Earlier this year, I spent some time at Northwestern State University in Northwest Louisiana to scan a collection of Caddo vessels from the Belcher and Gahagan sites. Many of these were illustrated and described by Dr. Clarence Webb; including this effigy vessel from the Belcher site.

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Dr. Webb’s  illustration (above) and description of this vessel:

Pottery vessel 3 of Burial 15, Belcher Mound, is a bird effigy vessel found with above 2 in NE corner. It is a small bowl of clay tempered ware, black core, and brown-black surface which is polished, with white pigment impressed into the engraved lines. The head is represented by a conical knob projecting at rim level, encircled by 5 parallel lines. The opposite tail is flat, at rim level, bifurcate or half-disc in shape, with 3 parallel arcs on the upper surface. Small flat tabs project from each side to represent wings, each also having 3 parallel arcs on upper flat surface, from base to tip. 3 parallel horizontal lines encircle the body of the bowl, just below the rim, except where they are interrupted by the projections. Convex base.

Many thanks to the Caddo Nation of Oklahoma, NCPTT, Dr. Pete Gregory (NSU) and the Williamson Museum for the requisite permissions, funding and access needed to scan these important Caddo vessels. 

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3D Natchitoches Engraved Vessel from the Williamson Museum

Natchitoches Engraved vessel (Caddo) curated at the Williamson Museum on the campus of Northwestern State University in Natchitoches, Louisiana and scanned with a GoSCAN50.

Many thanks to the Caddo Nation of Oklahoma and the Williamson Museum for the requisite permissions and access needed to scan this important artifact.

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Geometric Morphometrics and a 3D Caddo Vessel from the Sam Kaufman Site at SMU

While yes, this post contains a great interactive figure of an incredible Caddo vessel from the Sam Kaufman site (curated at Southern Methodist University #SMU), I wanted to take a moment to bring us full-circle, and return to the reason that I am scanning all of these vessels. Some time ago, I began getting fascinated by the high degree of variability in Caddo vessel shape and size, and have since also noticed some degree of variation in asymmetry.

At the same time that my interest in this topic began to increase, I also quickly realized just how much room for growth that there was in terms of applying geometric morphometrics to archaeological problems. It took time to get through the literature; and I kept finding new articles and book chapters listed in the references of my readings that had escaped the reach of my initial literature review.

Since I had been tinkering with social networking, I reached out to a colleague to assist me in building a citation network. That network has since been completed, and proved to be an invaluable asset in terms of not only centralizing the archaeological literature associated with geometric morphometrics, but it helped me to identify those works in the geometric morphometric literature that are most often cited (InDegree) and most important (identified using Google’s PageRank algorithm) to the overall network (click here to view the interactive network).

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Directed bipartite citation network for studies of geometric morphometrics in archaeology.

Having made my way through the literature, I began to think through the various methods of landmark and semilandmark applications that were available (based on the numerous research questions that could be asked of these data), and quickly found that the configurations were really only limited by my 3D modeling abilities. At that point, I ventured up to Lakewood, Colorado to spend some time working with the crew at Geomagic, where I learned how to use and employ the various features of Geomagic Design X and Control X (more here). Using these tools, I was able to devise a method of applying landmarks in a replicable manner using reference geometry that was built around the 3D mesh of the ceramic vessel. This first iteration of the landmark and semilandmark configuration worked very well for addressing some of my initial questions (see that in the video below).

From here, things began to get more complex. In October of last year, I headed to Portugal for what would be an important transitional period for my work; learning how to write scripts for, and run the various analyses in, the geomorph package in R. This opened something of a Pandora’s box for me, from which it is very likely that I will never fully recover. Needless to say, shape, form, allometry and asymmetry shifted quickly from a peripheral interest to something of a primary project.

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Procrustes superimposition of landmarks and sliding adaptive semilandmarks used in the analysis of Caddo ceramics.

Since then, there have been dozens of iterations and developments in my landmark and semi-landmark configurations and analyses; many of which (particularly those associated with my morphological integration inquiries) are actively evolving. I was fortunate to receive funding for much of this work through the National Center for Preservation Technology and Training (NCPTT); a group that I have really enjoyed collaborating with.

As you interact with this vessel from the Sam Kaufman site, consider where (and how) you would apply landmarks/semi-landmarks to the 3D surface.

In terms of theory, analyses of geometric morphometrics can be couched within several interesting anthropological lines of inquiry that include, but are not limited to, (1) identifying the locus of a specific innovation, (2) the spatial and temporal dynamics of morphological variation for specific elements (neck, body, base, etc.) of ceramic design, (3) identifying or refining social networks used by specific Caddo polities/groups during temporal periods previously defined—primarily—through design-based seriations, (4) intra/inter-polity/group variation of shape, form, allometry and asymmetry for ceramic design, (5) potential trade relationships based upon the presence of a specific shape/form of vessel outside of known (assumed) social boundaries, and (6) the power or influence that shifted among and between polities through time. These considerations could be woven into discussions of communities of practice, craft specialization, ceramic technological organization, politics, religion, and—possibly—inter/intra-polity disputes and warfare. Furthermore, this research design has the capacity to inform greatly upon the evolution of ceramic design as it relates to the shape, form, allometry and asymmetry that occurs in Caddo vessels, and by adding the related qualitative measures to our results we might just have the potential to bolster evidence for human behaviors associated with ceramic production and use within the larger ancestral Caddo territory.

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Historic era (1680+) Caddo networks based upon ceramic types (as I tip my hat to Dr. Timothy K. Perttula). Incorporating elements of vessel shape, form, allometry and asymmetry may help us to further refine this current iteration of the Historic Caddo network.

Initially a development in the biological sciences, the study of geometric morphometrics in archaeology will no doubt include some interesting discussions regarding the various analytical and theoretical components that are most appropriate for a cultural system versus a biological system as we continue to press forward. There remains plenty of thinking left to do on this subject, but based upon the preliminary results, the capacity for geometric morphometrics to inform upon issues related to material culture and cultural systems could be enormous.

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The very humble beginnings of exploring directional and fluctuating asymmetry in Caddo vessels.

Beyond the realm of empirical geometric morphometric studies, lies the domain of theoretical morphospace. Biologists have gainfully used theoretical morphospace to aid in clarifying issues of morphological change through time. They have done so by aggregating the results of geometric morphometric studies–a dialogue which would seemingly fit very well within the scope of anthropological and archaeological inquiry. By definition, theoretical morphospace represents the full range of possible morphologies for a group of artifacts; allowing investigators to posit, and contemplate, more- and less-adaptive morphologies (similarities and differences). 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. 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 ceramic morphological transition that remains hidden in the various vessel shapes once employed by Caddo potters.

So, while the 3D images are fun to interact with–and have any number of preservation, access and outreach perks–my intention is to use them to bolster our discussions of shape, form, allometry and asymmetry in Caddo ceramic studies, and to use that evidence to posit a number of novel insights into the highly variable and dynamic prehistoric landscape that the Caddo people once commanded.

Many thanks to the Caddo Nation of Oklahoma and Southern Methodist University (Dr. Sunday Eiselt in particular) for the requisite permissions and access needed to scan this important artifact from the ancestral Caddo territory, and to present the 3D model here in color.

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Large Caddo Vessel from the Belcher Site in 3D

Earlier this year, I spent some time at Northwestern State University in Northwest Louisiana to scan a collection of Caddo vessels from the Belcher and Gahagan sites. Many of these were illustrated and described by Dr. Clarence Webb; including this large Belcher Ridged vessel from the Belcher site.

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Dr. Webb’s  illustration (above) and description of this vessel:

Pottery vessel from floor of House 7, Belcher Mound A, found in sherds on this floor near an ash bed in SE sector. It is an immense jar of type Belcher Ridged, of which the upper half to three-fifths is preserved, the lower portion missing. It is clay tempered, with smoothed surface, colors vary from buff to gray to dark gray or brown. Shape is barrel-like, with moderately flaring rim. Decorated with vertical applique or pushed-up ridges, spaced 6 mm to 2 mm apart over the body; the outer surface of the rim has vertical incisions.

Many thanks to the Caddo Nation of Oklahoma, NCPTT, and Dr. Pete Gregory (NSU) and the Williamson Museum for the requisite permissions, funding and access needed to scan these important Caddo vessels. 


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3D Puzzle of the Large Biface from the George C. Davis Site

During a recent trip to the Texas Archeological Research Laboratory (TARL), I was able to scan an artifact that once caught my eye while researching another site in East Texas. When we think of Caddo artifacts, lithics are not usually the first class of artifacts that come to mind; as the Caddo are quite famous for their skill with ceramics.

This specimen (4078-63) comes from Feature 134 at the Davis site, and was associated with Skeleton 5. There is something adhering to the biface; according to Shafer (1973), this may be the remains of a leather sheath. He noted that edge smoothing and some polishing occurs almost around the full perimeter of the biface, which may have resulted from being carried in (and lightly abrading against) a loose sheath of bark or leather (Shafer 1973). This material is still adhered to the biface, and is also present on several of the Gahagan bifaces from the George C. Davis site. You can see it in the photo below, and it is also plainly evident in the 3D model. The biface is an impressive 480 mm (48 cm) in length.

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I did end up making a 3D puzzle of the large biface, using those data from the 3D model–you can download the plans here (https://works.bepress.com/zac_selden/203/). There are 37 puzzle pieces that can be cut out from five sheets of 8.5×11″ paper; so there is no need for a 3D printer. This puzzle is a bit more challenging than the ceramic puzzles. There are 754 triangles and 380 vertices–to put that in perspective, the full size 3D model has over 2,400,000 triangles and 1,200,000 vertices. As you build the puzzle, take some time to ponder the skill, care and craftsmanship that the original Caddo maker took to create such an incredible tool.

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Whether simply a rainy day activity with the family, or an engaging way to get students involved in thinking about local prehistory, these puzzles offer a creative, elegant and challenging alternative to all things digital. Having the 3D scans available for analysts to use is great; however, as archaeologists, we need to do more to raise awareness of these finite and important resources. Prehistory is underfoot–take some time to learn about local prehistory in your neck of the woods.

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3D Belcher Ridged Vessel from the Belcher Site

This Belcher Ridged vessel comes from the Belcher Site in Northwest Louisiana, is curated at Northwestern State University in Natchitoches, Louisiana. Funding to produce this 3D model comes from a grant to Selden from the National Center for Preservation Technology and Training. Many thanks to the Caddo Nation of Oklahoma, and Dr. Pete Gregory for the requisite permissions needed to access and scan this vessel.

 

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3D Caddo Vessel from the Sam Kaufman Site

Earlier this year, I visited SMU to give a short 3D scanning workshop, and to scan a number of Caddo ceramic vessels that are housed there as part of a larger pilot project with Dr. Sunday Eiselt. I just received permission from the Caddo Nation to post the red-slipped vessels in color, and wanted to share the first of these with you.

Many thanks to the Caddo Nation of Oklahoma, and to SMU for making this project possible.

 

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