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A Recap of STRI Archaeology in 2020

In spite of the unexpected Covid-19 epidemic in 2020, archaeology continues at STRI… although we’re counting down the days until we can get back to the field! In the meantime, here is a look back at some projects and discoveries made in the past year:

Disease in Ancient Panama

Nicole reading old reports
Nicole backtracking burial records. Photo by Ashley Sharpe.

Can we better understand modern diseases by learning from those in the past? Tropical diseases have been prevalent in Panama for thousands of years. Bioarchaeologist and STRI postdoctoral fellow Nicole Smith-Guzmán has been examining the bones of ancient Panamanians to understand what diseases they may have encountered, and how such ailments affected societies in the past. Among those she most frequently finds are infections caused by the Treponema bacteria, which include syphilis and yaws. In fact, some archaeologists believe syphilis may have originated in the Americas and spread to the rest of the world after Europeans arrived. Other ailments commonly found in ancient Panamanian populations include tooth infections from eating high-sugar foods (corn, fruit, and cassava), and bone lesions possibly left behind by serious bouts of malaria.

To read more about ancient tropical diseases, check out this article: STRI Stories – Ancient Diseases

Para leer en español: STRI Noticias – Enfermedades Antiguas

Buried with Snails, and Other Molluscan Mysteries

Pomacea snails
Pomacea snails from an early Maya burial at Ceibal. Photo by Melissa Burham.

The ancient Maya site of Ceibal is unusual: not only does it have some of the earliest evidence of large monuments in the Maya region, but it was also occupied much longer than most Maya sites – at least 2000 years! Examining the animal remains from this site gives us a long-term view of how humans changed their subsistence and ritual practices over the course of two millennia. STRI archaeologist Ashley Sharpe has been analyzing the Ceibal fauna for 10 years, and identified a number of significant trends over time that attest to shifting social practices across the centuries. Perhaps the most unusual trend was the mollusks: while snails and many river bivalves were commonly eaten and even used as burial items during the first half of Ceibal’s occupation, once it became a “Classic” Maya state center, these mollusks decline precipitously across the site. Curiously, this trend is not unique to Ceibal – it appears to have occurred across the Maya region. Did the later Maya decide to stop eating mollusks? Did something happen to the mollusks – perhaps a result of shifting agricultural practices to feed increasingly large populations? The disappearing mollusks are one of several changes that occurred once the Maya established large cities, demonstrating the impacts they may have had on surrounding habitats.

To read more about this story, check out the article here: STRI Stories – Buried with Snails

Para leer en español: STRI Noticias – Enterrado entre caracoles

Original Research Article:

Sharpe, Ashley E., Takeshi Inomata, Daniela Triadan, Melissa Burham, Jessica MacLellan, Jessica Munson, and Flory Pinzón 2020 The Maya Preclassic to Classic transition observed through faunal trends from Ceibal, Guatemala. PLOS ONE 15(4):e0230892. DOI:

Reconstructing Ancient Amazonian Forests

Aphelandra sinclairiana phytolith
Aphelandra sinclairiana (orange shrimp plant) phytolith under a microscope. Photo by Dolores Piperno.

There has been considerable debate in recent years regarding the extent to which pre-Columbian peoples impacted the Amazon’s forests. In order to address this question, STRI archaeologist Dolores Piperno, working with longtime collaborator Crystal McMichael (University of Amsterdam), has been striving to improve our ability to identify microscopic plant residues known as phytoliths. Phytoliths are tiny silica structures found in some plants, which often take on unique shapes that allow us to identify what plant they originally came from. Because they are made from silica, they survive much longer than other plant parts. Identifying ancient phytoliths in the ground can help us recreate past forest habitats. Piperno and McMichael’s new analysis of 360 different tropical plant species will help us determine what the Amazon looked like in the past, and whether humans had deforested or modified certain areas.

Original Research Article:

Piperno, Dolores R., and Crystal McMichael 2020 Phytoliths in modern plants from amazonia and the neotropics at large: Implications for vegetation history reconstruction. Quaternary International 565:54–74. DOI:

Clues of the Early Colonial African Slave Trade

Panama Viejo
Panama Viejo today. Photo by Ashley Sharpe.

Panama Viejo is one of the earliest European settlements in the Americas, but few realize it played a significant role in the African slave trade. Documents from the early 1600s indicate 70% of the settlement’s population were African slaves. Unfortunately, we know remarkably little about such a large proportion of the settlement. A new study by STRI postdoctoral fellow Nicole Smith-Guzmán and collaborating bioarchaeologists combines several methods for identifying the ancestry of ancient peoples, including dental modifications and isotope analysis, to document individuals from Africa and the roles they played in early colonial society. Significantly, it seems that dental modifications, common among certain African communities that were transported as slaves to Panama, may have been adopted by the local Ngäbe people and continue today. The reason for why this practice was shared to begin with remains a mystery.

Original Research Article:

Smith-Guzmán, Nicole E., Javier Rivera-Sandoval, Corina Knipper, and Ginés Alberto Sánchez Arias 2020 Intentional dental modification in Panamá: New support for a late introduction of African origin. Journal of Anthropological Archaeology 60:101226. DOI:

Deer at the Feast

Panama deer bowl
Polychrome plate depicting white-tailed deer (top half). Photo by Richard Cooke.

Ongoing analyses of ancient animal bones by former STRI fellow María Fernanda Martínez-Polanco (Universitat Rovira i Virgili), in collaboration with STRI archaeologist Richard Cooke and associate Anthony Ranere (Temple University), have found that deer were a prime food among ancient peoples of central Panama for several thousand years. At the site of Cerro Mangote, Martínez-Polanco found that deer were hunted from what may have been intentionally cleared agricultural plots in a form of “garden hunting”. This strategy was maintained for centuries, as people appear to have carefully selected adult individuals rather than juveniles or subadults. It was only after the formation of large sedentary villages that unsustainable hunting practices selecting increasingly young deer began to appear, perhaps because increasingly fewer adults were available.

Original Research Article:

Martínez-Polanco, María Fernanda, Anthony Ranere, and Richard G. Cooke 2020 Following white-tailed deer to the hilltop: A zooarchaeological and taphonomic analysis of deer hunting at Cerro Mangote, a Late Preceramic (7800-4600 cal yr BP) site in central Pacific Panama. Quaternary International. DOI:

Sweat Bath of the Gods

Los Sapos Sweat Bath
Detail from the “Los Sapos” (“Toads”) Sweat Bath. Photo by David Coventry.

Sweat baths have been found in ancient Mesoamerica dating almost 2000 years ago, and are still commonly used today for recreation. In the past, there is evidence they were used for healing the ill and by women before and after childbirth. A sweat bath over 1500 years old was recently found at the Maya site of Xultun in northern Guatemala, and may have been used for just such purposes. However, unlike most sweat baths – which are relatively plain affairs – the exterior of this bath depicted carvings and paintings of cane toads (Rhinella marina) and iguanas. In fact, to enter the sweat bath one had to enter the belly of a central toad-like figure! Inside the bath was another surprise – the remains of a dedication offering (including frogs, iguanas, and female figurines) that was placed in the structure centuries after it had been abandoned. It is difficult to interpret such a unique discovery, but one possibility may be that the final offering was made to honor the spirit of the sweat bath itself, since structures were believed to have been imbued with such spirits.

To read more about this story, check out the article here: STRI Stories – Amphibian Goddess

Para leer en español: STRI Noticias – Diosa anfibia

Original Research Article:

Clarke, Mary E., Ashley E. Sharpe, Elizabeth M. Hannigan, Megan E. Carden, Gabriella Velásquez Luna, Boris Beltrán, and Heather Hurst 2020 Revisiting the Past: Material Negotiations between the Classic Maya and an Entombed Sweat Bath at Xultun, Guatemala. Cambridge Archaeological Journal 31(1):67–94. DOI:

A New Look at the Earliest Migrations

Richard Cooke near Sarigua
Richard Cooke with shells found near Vampiros Cave and the early Sarigua sites. Photo from STRI archives.

When did the first humans arrive in Central America? This question remains largely a mystery. STRI archaeologists Richard Cooke and Anthony Ranere (Temple University) address this conundrum in a review of what we know about late Pleistocene/early Holocene migrations in Quaternary International. They compare the new sources of evidence that examine this question from different perspectives, including ancient DNA, linguistics, and artifactual evidence, particularly stone tools. They note that the primary reasons this question has remained unresolved is due to the fact that early peoples likely passed through regions near the coast that are now underwater (for instance, the Bay of Panama was once dry land), and that there are remarkably few known late Pleistocene/early Holocene sites. Nevertheless, new advances in genetics and other methods may provide important clues to address this mystery in the near future.

Original Research Article:

Ranere, Anthony J., and Richard G. Cooke 2020 Late glacial and Early Holocene migrations, and Middle Holocene settlement on the lower isthmian land-bridge. Quaternary International. DOI: