Preceramic maize from Paredones and Huaca Prieta, Peru.

Maize (Zea mays ssp. mays) is among the world's most important and ancient domesticated crops. Although the chronology of its domestication and initial dispersals out of Mexico into Central and South America has become more clear due to molecular and multiproxy archaeobotanical research, important problems remain. Among them is the paucity of information on maize's early morphological evolution and racial diversification brought about in part by the poor preservation of macrofossils dating to the pre-5000 calibrated years before the present period from obligate dispersal routes located in the tropical forest. We report newly discovered macrobotanical and microbotanical remains of maize that shed significant light on the chronology, land race evolution, and cultural contexts associated with the crop's early movements into South America and adaptation to new environments. The evidence comes from the coastal Peruvian sites of Paredones and Huaca Prieta, Peru; dates from the middle and late preceramic and early ceramic periods (between ca. 6700 and 3000 calibrated years before the present); and constitutes some of the earliest known cobs, husks, stalks, and tassels. The macrobotanical record indicates that a diversity of racial complexes characteristic of the Andean region emerged during the preceramic era. In addition, accelerator mass spectrometry radiocarbon determinations carried out directly on different structures of preserved maize plants strongly suggest that assays on burned cobs are more reliable than those on unburned cobs. Our findings contribute to knowledge of the early diffusion of maize and agriculture and have broader implications for understanding the development of early preindustrial human societies.

Cryptosporidium, Giardia, and Cyclospora in ancient Peruvians.

Twenty-two coprolites of human origin, collected from excavations along the north-central coast of Peru, were examined using fluorescent microscopy for the presence of fecal parasites, with emphasis on Cryptosporidium sp., Giardia sp., and Cyclospora sp. Three samples were positive. One coprolite dated between ca. 2,375 and 1,525 BC contained Giardia sp. cysts. This coprolite corresponded to the Peruvian preceramic period. Another positive coprolite ca. AD 770-830 corresponded to Epoch 3 of the Middle Horizon and contained Cryptosporidium sp. oocysts. The third positive coprolite (corresponding to the Middle Horizon. ca. AD 500-900) contained Giardia sp. cysts. This report demonstrates that Giardia sp. and Cryptosporidium sp. were present in Peruvian coastal populations for at least 4,300 and 1,100 BP.