That question has now been answered with laboratory evidence rather than stylistic argument. In a study published in American Antiquity, researchers at the Florida Museum of Natural History combined chemical fingerprinting with microscopic analysis of pottery from Tampa Bay and concluded that the vessels were made locally by migrants from the Florida Panhandle, the center of gravity of Mississippian culture. These artisans apparently carried specialized knowledge of clay processing and vessel construction hundreds of miles south, then used that expertise to establish a niche for themselves within the region’s existing Safety Harbor communities. The findings resolve a debate that has simmered since the sherds were first shelved in museum collections a century ago.

The cultural backdrop explains why the pottery was so puzzling. Around 1000 A.D., a new way of life took root in the Mississippi River Valley and radiated outward across much of the Midwest and eastern United States. In the heartland, Indigenous communities organized into regional hierarchies, with large chiefdoms concentrating political power over surrounding villages. They planted extensive fields of maize and quarried earth to build flat-topped mounds crowned with temples and elite residences. Tampa Bay, by contrast, sat on the southern edge of this world. The regional culture there, known as Safety Harbor, shared some Mississippian traits: communities aggregated into small chiefdoms, the largest centered on the Tocobaga, with the Mocoso, Pohoy and Uzita chiefdoms nearby, and they too built platform mounds. But no local group amassed the political scale of the northern centers, and the coastal communities never adopted maize agriculture, sustaining themselves instead on fishing and marine resources.

Given these mixed signals, archaeologists never fully understood how closely the coastal chiefdoms were tied to the Mississippian heartland, and the presence of Mississippian-style decorated pottery only deepened the uncertainty. Surface designs alone could not settle the matter, because motifs can be copied. What was needed was a way to look beneath the decoration, into the invisible decisions a potter makes before a vessel is ever fired. Trevor Duke, who began the research as a doctoral student at the University of Florida, and his colleagues assembled a sample of 58 pottery sherds from Tampa Bay, including both plain wares used for everyday cooking and serving and decorated vessels likely reserved for special occasions.

The first test targeted the clay itself. Using neutron activation analysis, the team measured the chemical composition of the sherds and compared it with that of raw clay sources around the region. The profiles matched, showing that every vessel in the sample, decorated or plain, had been made on-site from local clay. That result eliminated the trade hypothesis: the pots had not been manufactured in the Mississippian heartland and carried south. But chemistry could not yet rule out imitation, because a local potter copying northern designs would also use local clay. The decisive evidence had to come from the recipe hidden inside the paste.

To recover it, the researchers turned to petrography, a technique in which a thin slice of a pottery sherd is polished down to roughly half the width of a human hair. Light from a polarizing microscope passes through the section, revealing the voids, cracks and mineral grains that record how the clay was processed. The minerals can be identified by their color and shape under magnification, and from that, researchers can determine what was mixed into the clay. It is, in effect, a fingerprint of the people who made the vessel, preserving choices that no surface decoration can disguise.

Under the microscope, the Tampa Bay pottery revealed its secret. Several of the decorated fragments were tempered with grog, crushed pieces of old pottery mixed into fresh clay, a hallmark of some Mississippian pottery that improves a vessel’s ability to withstand the high temperatures of firing and cooking. Grog tempering appeared in none of the plain samples from Tampa Bay, but in the Tallahassee Hills, home to the nearest massive Mississippian mound center some 200 miles to the north, it is the standard tempering technique for all vessels. The connection ran deeper still: within the grog, the scientists identified mica, a shiny silicate mineral common to the Panhandle but not typically found in peninsular Florida. The host clay was local, but the particles mixed into it had come from the Mississippian heartland, apparently carried south by the potters themselves.

The contrast between the two vessel classes was stark. While 80 percent of the decorated pottery contained grog, not a single plain sherd did; most plain vessels were tempered with chunks of dry clay or sand, methods used in the region for the previous 3,000 years. The decorated pots were also shaped by coiling, the Mississippian technique, rather than molding, and were made with more consistent paste recipes, suggesting potters with advanced knowledge of clay processing. The plain wares, by contrast, were molded, a simple practice that could be quickly learned by novices as the region’s population grew. The most likely reconstruction is that migrant potters traveled from northern Florida carrying bags of their old decorated vessels, then crushed and ground that homeland pottery into the fresh clay of their new home. Every grog-tempered vessel contained multi-generational grog, fragments embedded within larger fragments like Russian nesting dolls, traceable through several generations of pots, and always drawn from the same lineage of decorated vessels. The migrants were quite literally incorporating pieces of their homeland into everything they made.

That expertise appears to have been the migrants’ ticket into an unfamiliar society. Their skill and their connection to Mississippian tradition would have set them apart, transforming commonplace homeland practices into valued services. Yet the knowledge stayed confined. The distinction between decorated and plain pottery persisted for centuries, and local residents never adopted the new techniques, whether because access was restricted or because the skills were simply too tightly held. The tempering, coiling and paste consistency are not clearly visible in a finished pot, so they cannot be easily mimicked without intimate access to the makers. The decorated vessels were also made from higher-quality clays than the plain wares, indicating the migrant artisans were granted access to a limited resource. As one of the researchers noted, secrets of this kind must be broadcast in part, so that people know a secret exists, and the circulating high-quality pots did exactly that, advertising a craft whose inner workings remained out of reach.

The study also offers a broader lesson in how migration reshapes material culture. Specialized knowledge passes directly from mentor to learner, and by tying homeland pottery into a chain of crushed and reused fragments across generations, the migrant potters may have been carrying their ancestors’ vessels into each new pot and the next generation. In Tampa Bay, a community of artisans found a way to matter in a new place, and the evidence of their arrival was hiding in plain sight for a century, waiting for the right instruments to read it.

Subject of Research: Compositional analysis of Mississippian-style pottery revealing migrant potters in pre-Columbian Tampa Bay, Florida

Article Title: Archaeologists uncover centuries-old mystery of Tampa Bay’s secret community of migrant potters

Article References: Archaeologists uncover centuries-old mystery of Tampa Bay’s secret community of migrant potters. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: Mississippian culture, Tampa Bay, Safety Harbor, pottery analysis, neutron activation analysis, petrography, grog tempering, migration, Florida archaeology, American Antiquity, Tocobaga, Florida Museum of Natural History

The journey to this scientific breakthrough began decades ago with a single, diminutive fossil vertebra about half an inch in size, discovered in early 2000 from a clay mine situated near the Florida-Georgia border. Despite its modest size, the fossil resisted identification for nearly 20 years, confounding paleontologists who debated whether it belonged to a lizard, a snake, or another reptile. It wasn’t until Jason Bourque, a fossil preparator and vertebrate paleontology specialist, revisited the specimen that the pieces began to fit together. Bourque’s meticulous examination hinted that the specimen bore a striking resemblance to tegu vertebrae, an insight that catalyzed further inquiry.

What followed was a fusion of traditional paleontology and cutting-edge technology. Recognizing the limitations of relying solely on expert morphological comparisons, Bourque collaborated with Edward Stanley, director of the museum’s digital imaging laboratory, to apply a novel machine learning approach to fossil identification. Using high-resolution CT scans, Stanley captured three-dimensional data on every anatomical nuance—the bumps, holes, and furrows—of the fossil vertebra. This 3D morphometric data was then analyzed alongside over 100 vertebrae from extant tegus and related lizard species, sourced from the museum’s openVertebrate (oVert) project, an expansive repository of vertebrate 3D images.

By implementing an automatic landmarking system devised by Arthur Porto, the museum’s curator of artificial intelligence for natural history and biodiversity, the research team bypassed the usual painstaking manual measurements. Porto’s algorithm adeptly recognized corresponding landmarks across the comparative vertebrae datasets, enabling precise shape analysis to pinpoint the fossil’s taxonomic identity. The result was unequivocal: the fossil vertebra belonged to a previously unidentified tegu species, which the researchers named Wautaugategu formidus. The genus name “Wautauga” references the local forest near the fossil site, inspiring a poetic connection to the "land beyond," while “formidus,” Latin for “warm,” alludes to the warm climatic conditions of its time.

The fossil dates back to the Middle Miocene Climatic Optimum (around 15 million years ago), a period characterized by elevated global temperatures and significantly higher sea levels. At this time, much of modern Florida lay submerged beneath shallow seas, with the terrestrial landscape concentrated near ancient coastal ridges where the fossil was found. Tegus, known for their terrestrial habits but also capable swimmers, may have exploited these warm conditions to expand their range northward from ancestral South American origins into what is now southeastern United States territory. This discovery effectively extends the known biogeographic range of prehistoric tegus far beyond current confines.

Yet, this prehistoric colonization was ephemeral. The absence of any tegus in fossil records before or after this thermal peak suggests Wautaugategu formidus was a transient experimental dispersal lineage, thriving only during the Middle Miocene’s warm span. The subsequent global cooling likely sealed their fate, as tegus’ reproductive physiology—highly dependent on temperature—would not have been sustainable in the cooler climates that followed. The cold may have limited egg incubation success, drastically reducing population viability and leading to local extinction.

This singular vertebra, small yet monumental, opens new avenues of inquiry into vertebrate dispersal dynamics and paleoclimatic influence on reptilian evolution. Bourque expresses keen interest in expanding fieldwork along the ancient coastal ridges near the Florida-Georgia boundary, hoping to uncover additional fossils that might flesh out the enigmatic existence of prehistoric tegus in North America. Such discoveries could illuminate evolutionary patterns and regional ecosystem transformations through geological epochs.

Beyond the paleontological implications, the study underscores the profound role of interdisciplinary research, particularly the integration of artificial intelligence and 3D imaging to accelerate fossil identification. Stanley emphasizes the significance of leveraging machine learning to reduce reliance on outdated manual assessments that demand decades of expert knowledge, a bottleneck that has left countless fossil collections unexamined. This technological synergy promises to revolutionize the speed, scale, and accessibility of paleontological research worldwide.

Moreover, the museum’s openVertebrate project exemplifies the power of open-access digital repositories in biodiversity science. By cataloging thousands of 3D vertebrate images, it facilitates global collaboration and comparative analyses previously impossible due to specimen scarcity and geographical limitations. In utilizing such resources, the Florida Museum’s team illustrates how digital natural history assets enhance and democratize scientific discovery on a scale matched to the challenges posed by the vast fossil record.

Ecologically, the story of Wautaugategu formidus offers valuable context for understanding the modern tegu invasion crisis. Today’s Argentine black and white tegus, introduced as pets, grow large and thrive in Florida’s subtropical environment, where they disrupt native ecosystems severely. The paradox of tegus’ ancient presence and modern invasive status invites reflection on how climate cycles, human activity, and species adaptability interplay to shape contemporary biodiversity.

The identification of Wautaugategu formidus also invites a recalibration of evolutionary timelines within Teiidae, shedding light on their diversification patterns correlated with Miocene climate fluctuations. The discovery encourages reexamination of fossil collections worldwide using similar advanced morphometric and machine learning methods, raising the prospect that other “mystery boxes” of fossil bones may harbor unknown species awaiting rediscovery.

Ultimately, this study exemplifies how a single bone, small enough to fit on a finger, can rewrite the history of an entire lineage and transform our understanding of ancient ecosystems. The melding of paleontological perseverance with innovative digital techniques points toward a new era, where unlocking the secrets of Earth’s past becomes more efficient, comprehensive, and revelatory.

Subject of Research: Tegus in the Middle Miocene Southeastern United States; paleontology and evolutionary biology of Teiidae lizards

Article Title: A tegu-like lizard (Teiidae, Tupinambinae) from the Middle Miocene Climatic Optimum of the southeastern United States

News Publication Date: 17-Apr-2025

Web References:
https://doi.org/10.1017/jpa.2024.89
https://www.floridamuseum.ufl.edu/overt/
https://www.floridamuseum.ufl.edu/science/florida-museum-hires-first-curator-of-artificial-intelligence-for-natural-history-and-biodiversity/

References:
Bourque, J., Stanley, E., Porto, A. (2025). A tegu-like lizard (Teiidae, Tupinambinae) from the Middle Miocene Climatic Optimum of the southeastern United States. Journal of Paleontology. DOI:10.1017/jpa.2024.89

Image Credits: Photo courtesy of Kevin Blackwell / Amphibian Foundation

Keywords: Reptiles, Paleontology, Invasive species, Climate change, Fossils