Original Articles
An Aztec omichicahuaztli from Tenochtitlan made out of a spider monkey bone
2025 Volume 133 Issue 1 Pages 17-22
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2025 Volume 133 Issue 1 Pages 17-22
This article examines an unusual small-sized omichicahuaztli from Tenochtitlan. Omichicahuaztlis are artifacts that were made out of long bones with incisions and, likely, functioned as musical instruments. The referred bone from the Mexica (Aztec) culture (1250–1521 CE) is exhibited at the Museo Nacional de Antropología in Mexico City. It has been identified either as a human or as a monkey bone. However, until now, it has not been studied in detail to test both contentions. Our morphological and morphometric analyses indicate that this specimen is from a platyrrhine femur (conferred to a Mexican spider monkey), and to our knowledge, it is the only of its kind among the Mexica and elsewhere in Mesoamerica. Archeoprimatologicaly, this unique omichicahuaztli stands together with confirmed findings of spider monkeys skins from a couple of offerings of the Templo Mayor of Tenochtitlan, and with other primate osteological remains apparently found in two other Mexica sites. Ethnohistorically, among the Mexica (Aztec), the spider monkey is the most represented primate and is usually related to the notion of fertility. The Mexica perception of primates ranges from the use of bones and skins in medicine to the connection of giving birth on a particular day related to musical inclinations. In summary, the symbolic connotations of Mexica perceptions of primates appear to be embodied in this specimen. This omichicahuaztli also serves as evidence of the circulation of an allochthonous mammal from the tropical lowlands to Tenochtitlan highlands.
In the Mexica Hall of the Museo Nacional de Antropología (MNA) in Mexico City, there is a collection of femurs conferred to humans that were gathered in the valley of Mexico (Figure 1A). These femurs display anthropic modifications known as omichicahuaztli (Pereira, 2005). The omichicahuaztlis are pre-Hispanic percussion musical instruments (idiophones), made from animal or human bones, with parallel grooves carved perpendicularly that produce sounds when rubbed against an object (Gómez, 2017). Its etymology comes from the Nahuatl Omitl–bone and Chicahua–to fortify, and produce strength: “bone that gives strength” (Bellomia, 2017). They were used especially in funeral contexts, documented in the chronicles of New Spain by authors such as Hernando de Alvarado Tezozomoc (ca. 1530–1610) and Bernardino de Sahagún (c. 1499–1490) (Stevenson, 1968). The omichicahuaztlis have been found in different regions of Mesoamerica such as in the Central Altiplano (Beyer, 1934; Von Winning, 1959), western Mexico (Pereira, 2005), the Oaxacan region (Sánchez, 2007; Higelin, 2012) and in the Mayan zone (Rivera, 1980). In central Mexico, the oldest ones correspond to the Middle-Late Preclassic of Chupicuaro, Guanajuato (Porter, 1956), when they were manufactured using deer antlers and scapulas. Among the Mexica, these modified bones correspond mainly to human femurs of adult individuals, predominantly males (Serrano-Sánchez, pers. obs.).
(A) The arrow indicates the little omichicahuaztli (inv. # 10-0116517;) as the object 2 of the vitrine 73 of the Mexica Hall at the National Museum of Anthropology (MINAH, 2017). The specimen is located in a prominent position within the vitrine (upper-center; see red arrow). (B) Detail of the modified femur in the exhibition (Photographs by B. Urbani)
Within the exhibition of Mexica omichicahuaztlis at the MNA, there is one that stands out because of its reduced size. In the institutional record, this specimen has been originally cataloged as a femur of a human individual (MINAH, 2017) (Figure 1B). On the contrary, Ardán (2012) suggested that this same femur seems to belong to a nonhuman primate (hereafter referred to as ‘primate’), specifically, a spider monkey. However, none of the proposals provided further analysis to support their identifications. Given these contentions and the very unusual nature of this omichicahuaztli because of its dimension, we study it in detail to determine its taxonomic classification which has remained elusive until now and explore possible cultural interpretations. To pursue this goal, we (a) describe the specimen and compare it with current human and primatological samples, (b) contextualize this modified bone within the Mexica archaeoprimatological and ethnohistorical records, and (c) examine the implication of the presence of this omichicahuaztli in the valley of Mexico.
The morphology and size of the studied femur were compared with the current material of the two extant primate genera of Mexico, namely, howler monkeys (Alouatta) and spider monkeys (Ateles) (Ceballos, 2014; Cortes-Ortíz et al., 2020). Specifically, they are Alouatta pigra (n = 2), Al. palliata (n = 1), and Ateles geoffroyi (n = 3). The material used comes from captive individuals and wild animals from the state of Chiapas and are deposited in the reference zoological collection of the Laboratory of Zooarchaeology at the Instituto Nacional de Antropología e Historia (INAH) of Mexico. In addition, human archaeological material (n = 5) from the Proyecto Salvamento Arqueológico Tabuco in the state of Veracruz State were measured in the Instituto de Investigaciones Antropológicas at the Universidad Nacional Autónoma de México (UNAM). In this research, a digital caliper with an accuracy of 0.01 mm was used for all morphological measurements (Mitutoyo; Kawasaki, Japan). Digital pictures were taken using a 50 mm lens mounted on a digital reflex camera (Nikon; Tokyo, Japan).
The comparisons consisted of the observation of the morphology of the bone as well as the performance of a multivariate analysis (Principal Component Analysis; PCA) using seven variables: (a) dorsoventral diameter of the femoral head, (b) lateromedial diameter of the femoral head, (c) distance between the femoral head and the great trochanter, (d) length of the femoral neck, (e) height of the great trochanter, (f) dorsoventrally width of the shaft, and (g) lateromedial width of the shaft. The analysis was carried out using the free statistical software PAST 3.20 (Hammer et al., 2001).
Primates Linnaeus, 1758
Platyrrhini Geoffroy, 1812
Atelidae Gray, 1825
Ateles Geoffroy, 1806
Ateles cf. A. geoffroyi Kuhl, 1820
Referred materialThe referred material (inv. number 10-0116517, cat. number 11.0-03739) is a right femur lacking the distal end and anthropically modified as an omichicahuaztli (Figure 1B).
ContextAccording to the institutional record (MINAH, 2017), the studied specimen is a human femur. This osteological piece cataloged as a musical instrument of the Mexica (Aztec) culture dated to the Late Postclassic Period (1250–1521 CE) from the central Mexican plateau. It was found in the excavation L-N:I during the construction of the subterranean train of Mexico City (MINAH, 2017). This excavation occurred during the 1960s in the core area of the Mexican capital city, overlapping ancient Tenochtitlan.
DescriptionThe dimensions of the specimen are 40% less robust than those of adult humans in both the femoral head and diaphysis diameters (Table 1; Figures 2A, B). Moreover, the great trochanter displays a more pronounced development compared to humans; instead, its form and shape closely resemble those found in the genera Ateles and Alouatta (Figure 2B). The femoral head is situated along the anterior axis of the great trochanter’s anterior end. Additionally, noteworthy, other features include a more developed fovea capitis compared to humans and a lesser trochanter less developed than in humans. The diaphysis of the specimen exhibits a noticeable curvature along the sagittal axis, a characteristic not observed in the reference primates used for comparison. This omichicahuaztli weighs 24 gr (MINAH, 2017). The apophysis for the insertion of the gluteus superficialis muscle is slightly smaller in atelins (Halenar and Rosenberger, 2013), and this characteristic is observed in 10-0116517.
Measurements (in mm) of the referred omichicahuaztli (inv. # 10-0116517)
| Anteroposterior diameter of the femoral head | Distance between the anterior border of the femoral head and the greater trochanter | Dorsoventral diameter of the diaphysis | Lateral diameter of the diaphysis | |
|---|---|---|---|---|
| Inv. # 10-0116517 | 17.2 | 8.5 | 10.2 | 12.0 |
(A) The little omichicahuaztli (inv. # 10-0116517): dorsal view (left), ventral view (right). (B) Comparison of the shape and size (at scale) of the studied specimen with adult femurs of a human and Mesoamerican atelines (Photographs by D. Ruiz-Ramoni)
Following Pereira (2005) criteria for anthropic modifications of human bones, the specimen displays 50 grooves/incisions on the dorsal face of the diaphysis, evenly distributed from the midpoint of the femur (Figure 1A). No scraping or cut marks are evident, except for those associated with the cutting of the artificially removed distal extremity. This femur and shows no signs of perforation, fracturing, or burning.
Size and morphological criteriaThe little omichicahuaztli is deemed to be from an adult due to the fusion of the femoral head with the femoral neck. Based on size and morphology criteria, it can be affirmed that this material does not belong to a human (Table 1). These observations were validated through a multivariate examination of the studied femur using Principal Components Analysis. The PCA results indicate that the specimen falls within the cluster of Mesoamerican platyrrhines, distinct from Homo sapiens (Figure 3). The assignment to the genus Ateles was determined by the positioning of the femoral head to the great trochanter. While there are not sufficient morphological characteristics in this femur to unequivocally identify it at a specific species, it is attributed to Mexican spider monkey as the Ateles species inhabiting the Mexican territory. The detailed systematic of the specimen is presented above.
Principal Component Analysis (PCA): referred specimen (inv. # 10-0116517) contrasted with human and platyrrhine samples. Variability: PC 1 98.01%; PC 2 1.06%
The morphology and morphometrics analysis of the modified femur (inv. # 10-0116517) correspond to a Mexican spider monkey, supporting the identification proposed by Ardán (2012). Despite this, our classification is restricted to Ateles cf. A. geoffroyi because, as commented above, the femur does not present all the diagnostic features to fully identify it at the species level (Silva-López et al., 1996). Currently, in México, the habitat of this frugivorous primate, the only species of spider monkey of Mexico, is confined to the southern and eastern coastal regions of the country in the states of Chiapas, Veracruz, Tabasco, Campeche, Quintana Roo, and Yucatan as well as the state of Oaxaca in the western portion of Mexico (Ceballos, 2014; Cortes-Ortíz et al., 2020). This species is known to inhabit various ecosystems, including tropical forests, mangrove forests, marshy forests, low subperennial forests, and hammock vegetation (Ceballos, 2014). This implies that Mexican spider monkeys do not naturally occur in central Mexico highlands where Tenochtitlan was settled. There are no paleontological records indicating the natural occurrence of this taxon during the past of this region. This suggests that the little omichicahuaztli was made out of a femur of an allochthonous primate as commonly observed for monkeys listed in the world archaeoprimatological record (see Urbani, 2021). Thus, it may have belonged to a wild animal brought from far tropical regions or it was bred in captivity in Tenochtitlan.
In central Mexico, during the Classic period (~200–550 CE), there is evidence of primates in three locations of Teotihuacan (Urbani et al., 2022; Sugiyama, et al., 2022). Later, another culture from this central region, the Aztec/Mexica, also possessed primates. In the main building complex of this society, the Templo Mayor of Tenochtitlán, there is evidence of biological remains, ˗skins of spider monkeys˗, in two offerings, the Ofrenda 125 (López-Luján et al., 2012) (Figure 4A) and the Ofrenda 174 (Morales-Mejía, 2018, pers. comm.). Ancient skins of primates are extremely rare in the archaeoprimatological record (Urbani, 2021). There are no archaeo-osteological remains of primates in the Templo Mayor (Álvarez and Ocaña, 1991; see reviews in López-Luján and Matos-Moctezuma, 2022). Nevertheless, in Tenochtitlan, apart from the little omichicahuaztli described in this study, there is another primate bone found during excavations of the subterranean train of the city (Álvarez and Ocaña, 1999). The same authors reported the existence of a cranium and a femur of a primate in a pre-Hispanic/early Colonial dump of Mexico City. If confirmed their presence, along with the spider monkey skin remains from two offerings of the Templo Mayor, Mexico-Tenochtitlan and this omichicahuaztli, it would add another locality to the list of global archaeoprimatological hotspots (after Urbani, 2021).
(A) Pre-Hispanic lithic knives covered with skins of spider monkeys from the Ofrenda 125 of the Templo Mayor, Mexico-Tenochtitlan (Museo del Templo Mayor. Photographs by B. Urbani) (B) Cuauhalahuac. Cihuapahtli. Quetzalhuexotl from the Codex Cruz-Badiano (Cruz 1991 [1552]; fol. 57r), medical preparations made out of monkey bones and hairs
In the ethnohistorical record, there are ample references to the perception and uses of primates (ozomatli in Nahuatl) among the Pre-Hispanic Mexica and their descendants during the early Colonial times in the 16th century (for a review: Urbani, 2019). In the Novo-Hispanic chronicles, spider monkeys are preponderantly reported as the primate species present in the region. Ateles is highly associated with the notion of fertility among the Mexica (see also Echevarría-García, 2015). In addition, concerning the features that are embodied in an omichicahuaztli such as its osteological nature sensu stricto or its possible use as a musical instrument, some ethnohistorical reports refer to these attributes in primates found in the valley of Mexico. For example, primate hairs and bones were sometimes combined with other ingredients to prepare medicines. Those medical remedies were made for treating various illnesses as well to facilitate birth or, on the contrary, abortion (e.g., Codex de la Cruz-Badiano: Cruz, 1991 [1552]) (Figure 4B). In addition, in the Florentine Codex (c.1577), Bernardino de Sahagún reported that children born on the day related to ozomatli might have aptitute for music performance (Sahagún, c.1577). In fact, this calendar day was considered a fortunate one as also children would be blessed with good conditions.
In sum, this is, to our knowledge, the only known omichicahuaztli made out of a monkey bone. It also is the only osteological remain of a primate fully studied from the Mexica (Aztec) archaeoprimatological record. Considering the archaeological and ethnohistorical record, this omichicahuaztli, eventually, appeared to have a particular symbolic value ranging from its musical attributions to possible conceptions of fecundity. To finish, this specimen proves the circulation of an allochthonous medium-sized mammal from the tropical lowlands of Mexico to the highlands of Tenochtitlan.
We would like to thank Bertina Olmedo-Vera, curator of the Mexica Hall of the MNA, for granting access to the specimen. We also appreciate the cooperation of Jessica Garrido-Guzmán at the UNAM for allowing the study of the reference collections under her care. We are grateful with Fabiola Monserrat Morales-Mejía from the INAH during the visit to the reference collection and for her communication about the presence of a monkey skin in the Ofrenda 174 of the Templo Mayor. We show our appreciation to Segundo Jiménez from the Instituto Venezolano de Investigaciones Científicas, for preparing Figure 4A. B. Urbani appreciates the support of the staff of the University of Illinois at Urbana-Champaing and the UNAM. In Mexico, D. R. R. received postdoctoral support from DGAPA-POSDOC-UNAM, while B. U. was supported by a visiting scholar fellowship of DGAPA-PREI-UNAM, the Coordinación de Humanidades-UNAM, and the Posgrado de Antropología-UNAM.
The authors declare no competing interests.
DRR, BU, and CSS designed the study and draft of the manuscript. DR performed the analysis. BU performed the data acquisition. CSS critically revised the manuscript.
