4.3.4. Archeoentomology
External examination of the mummy revealed multiple traces of activity of necrophagous insects. Although visible on a large part of the body, these stigmata are mainly located on the lower limbs and the perianal region. However, to a lesser degree, similar marks can be seen on the collar region and the face. These circular perforations result from the action of the digestive juices of dipteran larvae (flies), which have consumed part of the muscles, viscera and skin. Close examination of various parts of the body, especially the thighs and the perianal region, reveals the presence of a large number of extremely well preserved puparia11, attributable to a single species of Calliphoridae fly (Figure 4.10(a)).
Figure 4.10. Location of Calliphoridae diptera puparia (red arrows) (a) on the left thigh of the mummy (photo: © J.B. Huchet), and (b) in the abdominal region, internal view. Image: © Dr. C. Bou
In parallel, CT examination of the abdomen revealed the presence of innumerable thin-walled oval structures with aerial contents of identical size in the abdominal cavity (Figure 4.10(b)). These structures are unmistakably related to puparia of necrophagous Diptera and indicate an internal colonization of larvae that pupated in situ.
From a taxonomic point of view, the conformation of the puparia (notably the arrangement of the taste buds and the shape of the respiratory stigmata) indicates that they correspond to immature stages of Calliphoridae diptera (Chrysomyinae), a “pioneer” family of flies of forensic interest, which lay eggs on corpses in the moments following death. Morphologically, these puparia are similar to those of the genus Compsomyiops Townsend, 1918 (Figure 4.11). This taxon, mostly neotropical, has six species, three of which are found in Peru (Gonzalez-Mora et al. 1998). Unlike most of the synanthropic Calliphoridae flies used in forensic science for estimating the postmortem interval (PMI), species of the genus Compsomyiops show a strong preference for environments little or not influenced by human activities (i.e. asynanthropy) (Figueroa-Roa and Linhares 2002; Mariluis et al. 2008).
Greenberg and Szyska (1984), who studied the biology and ethology of two species found in Peru (Compsomyiops verena (Walker) and C. arequipensis (Mello)12), attest that the lifecycle of C. verena (egg to adult) varies between 15.2 and 19.7 days. At significantly higher temperatures, however, Dale and Prudot (1986) report a duration of 12.5 to 15 days for C. arequipensis. Based on observations by Greenberg and Szyska (1984), supplemented by Baumgartner and Greenberg (1985), C. arequipensis preferentially occupies high-altitude environments and C. verena low valley environments. Data from Mariluis and Schnack (1996) on the biology of representatives of the genus Compsomyiops in Argentina reveal that these species are particularly fond of forest and rural environments and are only active during the warmest months of the year. Finally, the experiments conducted by Figueroa-Roa and Linhares (2002) underline a very marked heliophilia13 in the species Compsomyiops fulvicrura (Robineau-Desvoidy) in Chile.
Although, as Greenberg and Szyska (1984) point out, the similarities between the immature stages of these two species cannot be denied, data from their biology and from the environmental characteristics of the site where the mummy was found (Reichlen and Reichlen 1950) allow us to hypothesize that the species could correspond to C. arequipensis (Mello) (Figure 4.11).
Figure 4.11. Remarkably preserved subfossil puparium of a Calliphoridae fly (Compsomyops cf. arequipensis (Mello)) from the mummy’s left thigh. Photo © J.B. Huchet
4.3.5. Cranial trepanation: location, size and mode of operation
The cranial trepanation present in the mummy, subcircular in shape and with a diameter of approximately 5 cm, extends over an area of more than 20 cm2 (Figures 4.12(a) and (b)). Endocranial 3D reconstructions show that this trepanation avoids the main pericerebral venous (superior longitudinal sinus, torcular, left lateral sinus) and arterial vascular structures (the imprints of the main branches of the meningeal arteries, visible in the endocranial view, are remote) (Figure 4.12(c)).
Figure 4.12. (a and b) Trepanation measurements. (c) Endocranial view of the trepanation site away from the main venous (white arrows) and arterial (red arrows) vascular structures. Image: (a) © Dr. C. Bou; images: (b and c) © Dr. S. Mérigeaud MD/Tridilogy
The edges of the trepanation preserve the trace of 20 microperforations, with a diameter of 0.7 and 1 cm, arranged in a circle, in a regular and confluent manner. A distance of approximately 1 cm between the center of each microperforation is maintained along most of the perimeter of the trepanation, with the exception of an area limited to 3.5 cm where the microperforations are positioned in a more irregular and constricted manner (Figure 4.12(a)).
In the experimental trepanation, the 20 microperforations were reproduced by rotating a flint tip along an axis vertical to the plane of the cranial vault. The rotations were first performed manually to initiate the perforation, and then with a bow until all perforations were joined (Figure 4.13(a)). The duration of the experiment, to obtain complete trepanation, was over four hours. At the end of the flap removal, the “jagged” morphology of the edges of the experimental trepanation was consistent with that of the mummy. More specifically, the similarity of the marks left by the rotation of the flint at the level of the external and internal tables and the diploe of the cranial vault with those observed on the archaeological case (Figures 4.13(b) and (c)) seems to confirm the technique used.
Figure 4.13. Experimental extraction of the trepanation flap. (a) Successive steps of the protocol until the bone flap was obtained. (b) Photo of the edges of the trepanation of MNHN-HA-30187. (c) Comparison of the edge obtained experimentally on dry skull. Photos: © Dr. C. Bou
4.4. Discussion
4.4.1. Identity of the deceased and health status
The Chachapoya mummy MNHN-HA-30187 is that of a male who died between 20 and 30 years of age, approximately 1.73 m in size (±2 cm). Consistent with an early age of death, the individual shows an overall “good” skeletal condition: no pathology, degenerative or traumatic, is noted, and despite the presence of three small carious inclusions, the oral condition is satisfactory, with moderate attrition and no ante mortem tooth loss. However, soft tissue imaging suggests that the male had an infectious lung disease. The presence of mediastinal calcifications suggests tuberculosis or granulomatosis. Tuberculosis is a disease known to have affected expanding Andean populations (Guillén 2012). Several cases were documented at the Laguna de los Condórès Chachapoya site, where 25% of 188 mummies studied were diagnosed with tuberculosis (Friedrich et al. 2010). At the scale of the Piedra Grande region, where mummy MNHN-HA-30187 originated, no epidemiological study has been conducted to date. If the diagnosis were confirmed, we do not know at this stage if the health status of the deceased is correlated with a specific burial treatment. In any case,