The two edited volumes reviewed here provide up-to-date overviews of their respective topics in Mesoamerican archaeology: the development of the early cities in the region (Early Mesoamerican cities) and the ways in which one such city grew to influence or control a large portion of the region (Teotihuacan and Early Classic Mesoamerica). Both volumes were developed from SAA (Society for American Archaeology) conference sessions and—for better or worse—this remains evident in their internal variability in the definition of key terms and the lines of evidence presented in different chapters. Both focus on identifying and discussing the processes behind observed phenomena, rather than binary determinations of whether a given case was or was not a city, state or empire. Most of the chapters in both volumes also include significant quantities of data generated over the past 10–15 years, which provide important updates to traditional narratives. In the case of Cities, the influx of new data is largely driven by the explosive potential of LiDAR to identify landscape-level settlement patterns in lowland portions of Mesoamerica, and the resulting chapters are biased toward lowland cases. In Teotihuacan, much of the new information comes from a majority-Mexican list of authors, who work at sites in a broad range of locations across the country. Both volumes deftly avoid rehashing what have historically been the most visible debates on each of their topics: the Olmec mother/sister culture debate and the nature of Teotihuacan/Maya interaction, respectively.

Tree-ring series offer considerable potential for the development of environment-sensitive proxy records. However, with traditional increment cores, only small amounts of wood are often available from annual tree-ring sequences. For this reason, it is important to understand the reliability (and reproducibility) of radiocarbon measurements obtained from small-sized samples. Here we report the F14C results from the Chronos 14Carbon-Cycle Facility of modern tropical Australian tree samples over a range of four graphite target sizes from the same rings. Our study shows that similar precision can be obtained from full-sized, half-sized, as well as small-sized graphite targets using standard pretreatment and analysis procedures. However, with a decline in sample size, there was an increase seen in the associated variance of the ages and the smallest target weights started showing a systematic bias. Wiggle-matching accuracy tests, comparing the Southern Hemisphere post-bomb atmospheric calibration curve to the different sample weight sequences, were all significant except for the 200 μgC graphite targets. Our results indicate that samples smaller than 350 μgC have limited accuracy and precision. Overall, reliable measurements of F14C sequences from tree-ring records across a range of sample sizes, with best results found using graphitized samples >350 μgC.

Se analizan los microrrestos biosilíceos recuperados en el sitio Fuerte Sancti Spiritus, primer asentamiento español que se estableció en la cuenca del Río de la Plata en el período de la colonización y conquista europea en América. Está emplazado en Puerto Gaboto, provincia de Santa Fe, Argentina, y consiste en una ocupación breve que se produjo entre mayo de 1527 y septiembre de 1529. La excavación se realizó de acuerdo con la metodología open area, por lo cual el muestreo estuvo distribuido en diferentes rasgos localizados en la planta del emplazamiento. Se analizaron 20 muestras según dos variables: tipo de rasgo y cronología, lo que permitió establecer que se cultivaba maíz, junto con trigo y probablemente cebada, introducidos, concordante con las fuentes etnohistóricas. El análisis permitió, también, estimar el contenido de los rasgos de acuerdo con el sedimento muestreado, posibilitando la caracterización de zonas de descarte, rellenos, niveles de uso y sedimento acumulado con posterioridad al abandono del asentamiento.

Shark remains are common in coastal archaeological sites in southern Brazil. Here we present an analysis of microwear visible on shark teeth found at the Rio do Meio site in Florianópolis, Brazil. It demonstrates that hafted shark teeth were used to work soft materials such as leather, as well as semihard materials such as wood and bone, whereas others probably functioned as arrowheads. The results also show a possible preference for tiger shark teeth use for woodworking. The identified technical motions include piercing, cutting, and scraping, as well as scaling and sawing. These findings allow us to question the common interpretation of shark teeth use as ornaments and as having symbolic value. Instead, shark teeth seem to have been used as tools and weapons in daily life.

In this paper, we present findings from a field inspection of the Knossos aqueduct undertaken in 2019. A key contribution of our fieldwork was the architectural identification of the Roman channel underlying the nineteenth-century wall of the Ottoman-Egyptian aqueduct supplying Iraklio. While reuse of the Roman aqueduct in the nineteenth century was known from historical reports, the structural overlap has never been identified in the field or documented archaeologically, until now. We recorded the Roman channel lined with opus signinum running along the base of the nineteenth-century aqueduct's wall between Fundana and Spilia. Through this realisation in the field, we were able to establish diagnostic styles of masonry for both periods. Our architectural distinction between the overlaid aqueducts allowed us to integrate previously disarticulated components of the later system, like the reused Roman tunnel at Skalani and the nineteenth-century bridge at Spilia, into an integrated Ottoman-Egyptian water supply for Iraklio. As we approached Knossos from Spilia, we were also able to identify the point at which the Venetian aqueduct supplying Iraklio converged with the Roman system. Consequently, our 2019 fieldwork not only mapped the length of the Roman aqueduct supplying the city of Knossos but also that section of the nineteenth-century Ottoman-Egyptian aqueduct of Iraklio built directly over it and a shorter tract of the Venetian aqueduct of Iraklio that either ran alongside it or was, in turn, itself partially overlaid by the nineteenth-century system.

Archaeologists tend to produce slow data that is contextually rich but often difficult to generalize. An example is the analysis of lithic microdebitage, or knapping debris, that is smaller than 6.3 mm (0.25 in.). So far, scholars have relied on manual approaches that are prone to intra- and interobserver errors. In the following, we present a machine learning–based alternative together with experimental archaeology and dynamic image analysis. We use a dynamic image particle analyzer to measure each particle in experimentally produced lithic microdebitage (N = 5,299) as well as an archaeological soil sample (N = 73,313). We have developed four machine learning models based on Naïve Bayes, glmnet (generalized linear regression), random forest, and XGBoost (“Extreme Gradient Boost[ing]”) algorithms. Hyperparameter tuning optimized each model. A random forest model performed best with a sensitivity of 83.5%. It misclassified only 28 or 0.9% of lithic microdebitage. XGBoost models reached a sensitivity of 67.3%, whereas Naïve Bayes and glmnet models stayed below 50%. Except for glmnet models, transparency proved to be the most critical variable to distinguish microdebitage. Our approach objectifies and standardizes microdebitage analysis. Machine learning allows studying much larger sample sizes. Algorithms differ, though, and a random forest model offers the best performance so far.