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The First Human Settlers on the Yucatan Peninsula: Evidence from Drowned Caves in the State of Quintana Roo (South Mexico)

Eberhard Frey
Jeronimo Aviles
ARTURO GONZALEZ GONZALEZ
Adriana Velazquez Morlet
Martha Benavente
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The First Human Settlers on the Yucatan Peninsula: Evidence from Drowned Caves in the State of Quintana Roo (South Mexico)

The First Human Settlers on the Yucatan Peninsula: Evidence from Drowned Caves in the State of Quintana Roo (South Mexico)

    Eberhard Frey
    Jeronimo Aviles
    ARTURO GONZALEZ GONZALEZ
    Adriana Velazquez Morlet
    Martha Benavente
F C O P Y PROO The First Human Settlers on the Yucatan Peninsula: Evidence from Drowned Caves 399 Chapter 19 The First Human Settlers on the Yucatan Peninsula: Evidence from 1 Drowned Caves in the State of Quintana Roo (South Mexico) 2 Arturo H. González1, Alejandro Terrazas2, Wolfgang Stinnesbeck3, Martha E. Benavente2, Jerónimo Avilés4, Carmen Rojas5, José Manuel Padilla1, Adriana Velásquez5, Eugenio Acevez4, and Eberhard Frey6 ABSTRACT Prehistoric evidence from submerged caves and sinkholes (cenotes) on the Yucatan peninsula provides strong evidence for the existence of an early preceramic human settlement in southern Mexico. During our ongoing paleoanthropological research we have already documented three well-preserved human skeletons as old as 13,000 and 9000 years from these sites in Quintana Roo (Gonzalez et al. 2008a, Gonzalez et al. 3 2008b). The findings were associated with hearths and a diverse megafaunal assemblage of late-Pleistocene age. A fourth human skeleton was discovered in 2009, two more in 2010, and two others in 2011. Here we provide a first register of these additional five skeletons, bringing the total assemblage to eight. A ninth skeleton was informally reported from the same area by INAH researchers. These findings thus constitute one of the largest databases on bones of early humans in Mexico. 4 KEYWORDS: Cenotes, Mexico, Quintana Roo, Karst, Human settlement, Paleoamericans, Pleistocene, ­Holocene, Underwater archaeology Introduction quickly disappears into the limestone of a kilometers-thick car- The northern part of the Yucatan Peninsula in Southeast Mexico bonate platform and runs subsurface to the sea. The ground is is a flat landscape where no surface rivers flow because the rain pierced by vine-draped sinkholes—cenotes, as they are called lo- cally—where the roofs of underground caverns have collapsed 1 (Lopez Ramos 1975; Smart et al. 2006; Ward et al. 1985). Phre- Museo del Desierto, Saltillo, Mexico 2 Área de Prehistoria y Evolución del Instituto de Investigacio- atic levels are reached only a few meters below surface. From 6 nes Antropológicas de la Universidad Nacional Autónoma de here the discharge of ground­water is rapid and directed towards México (UNAM) the coast. The enormous degree of karstification and limestone 5 3 Institute of Earth Sciences, University of Heidelberg, Germany permeability in the subsurface of the northern Yucatan led to 4 Instituto de la Prehistoria de America, Playa del Carmen, Mexico the formation of one of the most extensive active cave systems 5 Instituto Nacional de Antropología y Historia, Tulum, Mexico worldwide, with an explored length of approximately 700 km 6 Staatliches Museum für Naturkunde, Karlsruhe, Germany and a presumed extension of 7,000 km (Quintana Roo Speleologi- Corresponding author e-mail:  1arteconciencia@yahoo.com cal Survey (QRSS), www.caves.org/project/qrss). F C O P Y 400 PROO This enormous subterraneous karst labyrinth was formed González et al. of 23 m, 24 m, and 9 m, respectively, in the submerged cave during the last two to three million years, mostly during the systems, which must have been flooded during early stages Pleistocene (Ward et al. 1985). During the glacial stages of of the Holocene sea-level rise. this geological period, precipitation in the northern Yucatan The taphonomic circumstances suggest that at least peninsula was likely higher and sea level 100 m and more be- two skeletons, Las Palmas and Naharon, were intentionally low the level of today (Blanchon and Shaw 1995; Moseley et deposited. The position of El Templo individual suggests 7 al. 2013). Sea-level rise at the end of the Pleistocene and early an accidental death. We assume that these skeletons are Holocene was caused by the global deglaciation, between of latest-Pleistocene/early-Holocene age based on radio­ 13,000 and 7,600 before present. This eustatic rise of the sea metric dating (Tables 19.1, 19.2). The Naharon individual, level was considered “catastrophic” by Blanchon and Shaw also known as “Naharon Woman,” was discovered by G. (1995). The present-day sea-level was reached about 6600 cal Walten and J. Coke and subsequently reported to one of yr BP (Gabriel et al. 2009). us (JA). Her age at death was estimated at 20–30 years. Without the sinkholes and caves with groundwater, Her death was dated on bone collagen to 11,570 ± 65 14C 8 much of northern Yucatan would be a waterless plain and yr BP (UCR4000A), using mass spectrometer acceleration one of the most inhospitable regions in the world because techniques (MSA) (Gonzalez et al. 2008a, Gonzalez et al. 13 of paucity of fertile soil, the scarcity of drinking water, and 2008b). Nevertheless, these ages must be considered with shortage of other natural resources (Ward et al. 1985). caution, because the amount of organic matter detected Nevertheless, one of the most sophisticated pre-­Columbian in the bones is extremely low (Taylor 2009). The Las Pal- civilizations, the Maya, did indeed cope with these adverse mas individual (Tables 19.1, 19.2), also known as “Mujer de environmental conditions. Recent archaeological discoveries las Palmas,” a female discovered by J. Coke and reported in the Mexican state of Quintana Roo suggest, however, that to one of us (JA), reached an age of 44–50 years and was 9 the arrival of humans to this region was much earlier and dated to 8050 ± 130 14C yr BP (UGA-6828) using 14C, and dates back to the end of the Pleistocene, thousands of years to 12,000–10,000 BP using U/Th techniques (Gonzalez et prior to the classic Mayan civilization. (Gonzalez et al. 2008a, al. 2008a, Gonzalez et al. 2008b). The El Templo individual Gonzalez et al. 2008b). (Tables 19.1, 19.2) was a male 25–30 years old at the time In 2008 we documented paleontological and anthropo- of death. It was discovered by S. Gerrard, G. Klag and D. logical evidence from about a dozen sites in the Tulum area Martin, and reported to one of us (JA). Bone tissue was of Quintana Roo. The fossil assemblage is of late-Pleistocene too much degraded and collagen contents too low to get to early-Holocene age (Gonzalez et al. 2008a, Gonzalez et reliable radiometric 14C ages. Criteria for identifying sex al. 2008b). The association includes horses, foxes, agoutis, and age of the El Templo male were already reported by peccaries, bats, elephants, tapirs, llamas, ground sloths, and Gonzalez et al. (2008a). glyptodonts. Some of these animals are widely known from The discovery of human skeletons associated with 14 10 North America as characteristic of shrub-type vegetation. At hearths and a diverse faunal assemblage of latest-Pleistocene or near the Pleistocene/Holocene boundary, however, the age clearly indicates an early human settlement on the Yu- dominant vegetation of thorny shrubs disappeared and tropi- catan peninsula reaching back to the late Pleistocene or early cal forests arose. They quickly became dominant at approx. Holocene. 9000 years BP (Leyden 1995; Brenner et al. 2002; Leyden et Here we present new anthropological evidence from our al. 1993). ongoing research and report on five additional human skele- Among the most important discoveries (reported by tons from the cave systems of Quintana Roo state. These skel- 15 Gonzalez et al. 2008a, Gonzalez et al. 2008b) were three hu- etons, here referred to as Chanhol I, Chanhol II, Muknal, Pit man skeletons called Naharon, Las Palmas, and El Templo, I, and Pit II (compare Tables 19.1 and 19.2) were discovered 12 which are almost complete (> 80%) and anatomically articu- since 2008. A ninth individual was recently reported from lated (Tables 19.1, 19.2). They were recovered from depths the same area at Cenote Black Hole by Instituto Nacional de Table 19.1  Complete list of human skeletons. Site Cave system Cave subsystem Cenote entrance Distance from entrance (m) Depth (m) Discoverer Naharon Ox Bel Ha Naranjal Naharon 368 23 G. Walten and J. Coke Las Palmas Ox Bel Ha Muknal Palmas 174 24 J. Coke El Templo Templo ElTemplo 185 10 S. Gerrard, G. Klag, and D. Martin 11 Chan Hol I Toh Ha - Chan Hol 547 8 A. Kampe and T. Kampe Chan Hol II Toh Ha - Chan Hol 1240 8 H. Gust Muknal Ox Bel Ha Muknal Palmas 210 33 J. Aviles El Pit I Sac Actun Dos Ojos Pat Jacinto 47 30 Unknown El Pit II Sac Actun Dos Ojos Pat Jacinto 12 45 Unknown F C O P Y PROO The First Human Settlers on the Yucatan Peninsula: Evidence from Drowned Caves Table 19.2  Homogenized radiometric ages of human remains discovered in submerged caves of Quintana Roo, Mexico. Calibrated in Oscal 4.2 using the 401 Inical 09 data set. Site Sample number Laboratory Technique Radiocarbon or U/Th age Calibrated age (cal yr BP) 14 Naharon UCR4000A U. C. Riverside C AMS collagen 11,570 ± 65  11,771–11,404 (95.4%) 14 Las Palmas UGA-6828 U of Georgia C AMS collagen 8050 ±130 7356–6641 (94.8%) 16 Las Palmas Oxford    U/Th 10,000–12,000 El Templo   -   - -   -   - 14 Chan Hol I KIA-43520 Kiel C in apatite 9589 ±49  9194–8792 (95.4%) Chan Hol II   -   - - -   - Muknal UNAM-1240 UNAM 14C in charcoal 8890 ±100 9732–10,298 (98%) 14 El Pit I KIA-43524 Kiel C in apatite 11,332 ±64  11,396–11,150 (95.4%) Antropología e Historia (INAH) researchers. The assemblage Here we document several new locations in the Tulum 17 now represents the largest database on bones of early hu- area. At Chan Hol cave, two human skeletons were recently mans in Mexico. discovered, but one of them (Chan Hol II) was subsequently 18 Table 19.1 shows the complete list of human skeletons. stolen from the submerged cave and only about 10% of this 22 skeleton could be recovered. Two skeletons discovered at Pat 19 New Discoveries about Early Human Settlement in Jacinto (formerly known as “El Pit”) as well as one at Muknal Yucatan cave were saved from potential vandalism. Both localities are Figure 19.1 shows the coast of the Mexican state of Quintana visited by an increasing number of recreational cenote and Roo with the location of cenotes and caves containing sites cave divers via newly constructed roads to these cenotes. with human skeletons and associated Pleistocene to early- Holocene fauna. The area of study stretches from Tulum to- Chan Hol 23 ward Playa del Carmen. All sites are between a few hundred The Chan Hol cave, which forms part of the Toh ha system, 20 meters to a maximum of 10 km from the actual coastline. was first explored by Kim Davidson in 2005. The known ex- Black dots mark sites that contain human evidence; white tension of the cave system is estimated today at more than 24 dots represent sites that contain animal evidence; black-and- 5000 m. The main entrance, known as Chan Hol cenote, is white dots indicate sites that contain both human and animal located approximately 15 km south of Tulum close to high- evidence. way 307, which connects Tulum with Playa del Carmen. The 21 Figure 19.1  Coast of the Mexican state of Quintana Roo with location of cenotes and caves containing sites with preceramic human skeletons and associated Pleistocene fauna. The area of study stretches from Tulum toward Playa del Carmen. All sites lie between a few hundred meters to a maximum of 10 km from the actual coastline. F C O P Y 402 PROO entrance is semilunar in shape, 3–4 m wide, and partially González et al. and may have caused the fracture of the diaphysis of the right covered by a natural roof of limestone. Water level at this humerus in its distal third (Figure 19.4). entrance is shallow, only about 0.5–0.8 m deep, but deepens Unrelenting contact with slowly flowing fresh water gradually to a cave 8–10 m deep. Two human skeletons dis- resulted in poor preservation of the skeleton. Bones are covered in the Chan Hol cave were named by us Chan Hol I, exceedingly fractured and fragmented and spongy bone also known as “El Joven” (Figure 19.2) and Chan Hol II, also is mostly dissolved. Despite the poor preservation, ana- known as “La Niña” (Figure 19.3). tomical relationships are clearly recognized and indicate 29 that an overall original anatomical position is preserved, 27 Chan Hol I including even tiny segments of extremities such as pha- The Chan Hol I skeleton was discovered in 2006 by cave ex- langes (Figure 19.5). plorers Alexandra and Thorsten Kampe and reported to us by The Chan Hol I skeleton is about 90% complete, but only Robbie Schmittner. It is located approximately 530 m north- 60% of the bones were sufficiently well preserved to be col- 28 east from the entrance. Depth at the site is 8 m. The skel- lected, owing to dissolution of the bone substance. The flexed 30 eton was found partially articulated and in a lateral position, position of both legs, and the fact that even the smallest bones resting on its left side, with legs flexed to the body at an of hands and feet maintain their anatomical position, clearly angle of about 90 degrees. The right arm was stretched out. indicate that skeletonization occurred on site, at a time when A stalactite, about 1.2 m in length, had collapsed on the arm the cave was still dry and not yet filled with water. 25 Figure 19.2  The Chan Hol I skeleton. Figure 19.3  Chan Hol II individual before 26 looting of the skull and other bones. Photo courtesy of Liquid Jungle. F C O P Y PROO The First Human Settlers on the Yucatan Peninsula: Evidence from Drowned Caves 403 Figure 19.4  Chan Hol I skeleton. The figure shows a detail of Figure 25.2. A stalactite fell 34 from the cave roof and fractured the humerus. Figure 25.5  Left foot of the Chan Hol I skeleton. Note that bones (e.g., talus, cuboid, metatarsals, and phalanges) maintain 35 their original position, indicating an in situ skeletonization in a dry cave. The strong dissolution observed in most diagnostic ele- ized by an unknown cave diver during the summer of 2012. At 31 ments of the Chan Hol I skeleton prevents our determining present, only a few photographs exist from the site prior to reliable data regarding the sex or age at the time of death of vandalization (Figures 19.6, 19.7). These photos indicate that this individual. the Chan Hol II individual was likely > 80% complete, including the skull, and that decay and skeletonization occurred in situ. 32 Chan Hol II After the looting of the Chan Hol II site and robbery of The Chan Hol II skeleton is located in a small cave tunnel ap- the skull and numerous large bone elements, we returned to proximately 1,200 m west of the Chan Hol cenote, at a water the location in October 2012 to collect all bone fragments, 36 depth of only 8 m and thus at a similar depth as the Chan Hol I which remained dispersed on the cave ground or were ad- 33 individual. The tunnel is reached via the same cenote entrance. hering to an aragonite layer covering the cave bedrock lime- The skeleton was discovered in early 2009 by Harry Gust and stone. Even though the majority of these bone fragments reported to one of us (JA). Subsequently the site was vandal- were small, less than 50 mm in size, they represent approxi- F C O P Y 404 PROO mately 10% of the skeleton. We collected 51 fragments which González et al. the Caribbean Ocean. With 243.031 km of explored caves correspond to ribs, 6 vertebrae, fragments of feet and hands, and tunnels, it has absorbed all neighboring systems. At one patella, 6 fragments of tibiae, 2 of the left humerus, 3 of least 140 different cenotes lead to this huge system, many the left radius, one of the clavicle, 4 teeth, various fragments of them very popular among cave divers.  Maximum depth of the pelvis, 3 of the scapula, as well as single fragments of recorded in the system is 34.7 m at the Muknal archaeo- the temporal and occipital condyle. logical site, from which a human skeleton is reported here. The arms and legs of the skeleton were articulated and The ongoing exploration and mapping of caves in the Tulum 37 preserved in an anatomical position. In addition, a large sta- area has shown that the Ox Bel Ha system is connected to other lagmite grew on the pelvis of the skeleton. systems in the area, including the Naranjal and other systems Incisive teeth recovered from both the Chan Hol I and Chan as well as the Muknal cave. In these cases the larger system (Ox 42 Hol II individuals present a “sinodont,” shovel-shaped, morphol- Bel Ha) swallows up the smaller ones and only the name of the 38 ogy, and thus provide an important source regarding the biologi- larger system is retained. Following this nomenclature, the Nara- cal affiliation of these early settlers and their origin in relation to njal system has recently been absorbed by the Ox Bel Ha system. the populations in East and North Asia (cf. Turner 1990). For a better understanding of terms already introduced to the anthropological literature (e.g. Gonzalez et al. 2008a, Gonzalez 39 Ox Bel Ha System et al. 2008b), we here maintain the term Naranjal sub-system, as Ox Bel Ha is located in the Tulum area. This huge system ex- well as Naharon and Muknal remote siphon areas which are part tends from the jungle and mangroves south of Tulum to of the Naranjal system (“QRSS” 1989–2001). Figure 19.6  Chan Hol II individual before looting of the skull and other bones. Note that a stalagmite grew on the pelvis of this 40 skeleton, thus indicating that the cave floor was dry during and after skeletonization of the corpse. Photo courtesy of Thomas Spanmberg. Figure 19.7  Chan Hol II site after looting of 41 the cranium and the major portion of bones of this skeleton. Only small fragments remained on the cave floor. F C O P Y PROO The First Human Settlers on the Yucatan Peninsula: Evidence from Drowned Caves 405 43 Figure 19.8  Map of the Naranjal cave and cenote system adjacent to Tulum, Quintana Roo, with location of anthropological sites described here. Modified from QRSS (2007). Note that three human skeletons were recovered from this subterraneous system so far. 44 Naranjal tensive accumulation of charcoal (Figure 19.10). The charcoal Prior to the discovery of its connection with the Ox Bel Ha layer is 0.1–0.5 m thick and spreads over an area 30 m long 49 45 cave system, the Naranjal system had a mapped length of and 2 m wide. A charcoal sample taken from below the Muknal 14 24.5 km, with 8 known entrances (Figure 19.8). skeleton was dated to 8890 ± 100 C yr BP (UNAM-1240) at Two preceramic human skeletons, Naharon and Palmas, the UNAM laboratory (Instituto de Investigaciones Antrop- have already been documented from Naranjal system by Gon- ológicas) using C-14 Liquid Flash Spectrometry techniques. zalez et al. (2008a, Gonzalez et al. 2008 b; Tables 19.1 and Some of the superficial bone tissue of the Muknal in- 19.2). The Naharon Woman was 20–30 years old at death. dividual has been lost from chemical dissolution as well as The skeleton was discovered in an articulated condition, in- abrasion, even though there is no evidence of water-borne dicating decay occurred in situ (Gonzalez et al. 2008a, Gonza- transport. For instance, no traces of erosion or rounded mar- 50 lez et al. 2008b). The “Señora de Las Palmas” was discovered gins are recognized on bone surfaces or fracture margins. about 1 km distant from the Naharon individual in an area Bone is pale yellow in color, but black patches are present, 46 of the same cave system known as Muknal remote siphon, likely resulting from contact with the charcoal concentrated at a depth of 24 m and a distance of 174 m from the near- on the cave ground. est entrance. This individual had reached an age of 44–50 The Muknal skeleton is approximately 50% complete, in- years. The skeleton was articulated, with the legs flexed to cluding skull, mandible, cervical bones, and some long bones. the body, suggesting an intentional deposition, likely a funer- The skeleton was not found articulated; instead, bones were al. Figures 19.9, 19.9A, and 19.9B show the reconstruction distributed randomly (Figure 19.11). It is unclear whether of the Las Palmas female, completed in 2010 at the Atelier they were transported to the site by water run-off, which ap- 51 Daynes Studios at Paris, France, by Elisabeth Daynes. pears unlikely from its location in an elevated location on the Subsequent to the findings of the Naharon and Las Pal- Muknal cave floor adjacent to the charcoal accumulation as mas individuals, further reconnaissance and exploration of well as the absence of transport marks on the bones. Alterna- 47 the Naranjal system led to the discovery by one of us (JA) of tively, prehistoric settlers may have deposited some skeletal a new skeleton only 60 m from the Las Palmas site at a depth parts at the Muknal site. This latter interpretation appears to of 33 m. Here we refer to this new skeleton as the Muknal be more likely based on the evidence. individual. Osteology of the Muknal individual 55 48 Muknal Individual Skull  As a result of post-mortem fractures and superficial dis- The Muknal skeleton was found at a location elevated about solution of the ethmoid and the internal portion of the orbits, 56 0.5 m above the cave floor within and partially overlying an ex- only the wings and spines of the sphenoid are preserved. F C O P Y 406 PROO González et al. B A post-mortem fracture is identified in the infe- rior portion of the malar. The zygomatic arches are fractured; margins are clearly recognized, suggest- ing that the fracture is recent. In the maxillae, the entire portion adjacent to the sphenoid is lost, in- cluding the posterior alveolar region from the first A molar in the right side and all teeth from the third molar on the left side. The upper anterior portion of 53 the right maxilla is also missing, as well as the plate of the ethmoid, the infraorbital margin, and inferior margin of the maxilar. Almost the entire base of the cranium is lost, with only the posterior margin of 52 Figures 19.9, 19.9A, 19.9B  Reconstruction of the Las Palmas female, performed in 2010 at the Atelier Daynes at Paris, France, by Elisabeth Daynes. Photo courtesy the foramen magnum preserved. Fractures on the Elisabeth Daynes. cranial base preserve black rims indicating that they F C O P Y PROO The First Human Settlers on the Yucatan Peninsula: Evidence from Drowned Caves are considerably older than fractures, which affected the cit.). Chin morphology is modified due to alveolar absorption 407 facial region. caused by the loss of teeth; a marked triangular chin is present Most teeth were lost ante mortem, among them the and in the range of grade 3 to grade 4. These criteria indicate right lateral incisive, the second right premolar, the left ca- that the Muknal skeleton represents a male individual. 54 nine, and the first left premolar and first left molar. A possible left premolar of the upper jaw and badly preserved roots of Age 63 other unidentified teeth are preserved. The following criteria were used to estimate the age of the Skullcap and the right orbit are unfractured, but part of Muknal individual: Despite the fact that the individual lost all 57 the left malar and the central portion of the maxillar were molars during life, the eruption of the third inferior and supe- integrated into their original anatomical position in the lab. rior molars was completed. The few teeth that are preserved in the mandible show extreme abrasion, reaching grade I of 64 58 Sex of the Muknal individual dental attrition in the scale of Lovejoy (1985 in White and 59 To determine sex in a fossil human cranium, the following Folkens 2000), whereas the maxillary teeth abrasion reaches characters need to be considered: grade H. This suggests that the age of the individual may 1) morphology of mastoid apophyses, range between 45 to 55 years, considering the mandible, and between 40 and 50, based on the maxilla. 2) occipital condyles, Cranial sutures were analyzed following the methodology 3) muscular incertation of the occipital established by Lovejoy and Mendl (1984 in White and Folkens 4) frontal protuberances, 2000), suggesting an age of 48.5 (SD 10.5) for the first sutures 5) the width of the zygomatic arcs, group, and 56 (SD 8.5) for the second. However, these standard 61 67 techniques are known to present a wide range of error and the 6) the supraorbital margin, Muknal individual shows little bone-tissue degeneration. The 7) orbital delimitations, age at death may therefore be lower than proposed above and 8) the form of palatinal bones, and may actually range between 40 and 45 years. 9) the mandible architecture (Brothwell 1987 in White and Folkens 2000). Pathologies 68 The Muknal individual shows evidence for pathological pro- The interpretation of sex follows the propositions of cesses, principally based on dentition. The ante-mortem loss, Buiskra and Ubelaker (1994): Superciliar arches are medially in the maxilla, of the two central incisors, the left lateral inci- marked. They fuse with the glabella to form a robust bulge, as- sor, the second left premolar, the left molar, and all three right sociated to grade 4 in the scale of Buiskra and Ubelaker (1994). molars is indicated by alveolar reabsorption. The remaining 69 62 The nucal crest is little accentuated, reaching grade 3 in this first right premolar and second left molar show evidence of scale, whereas the mastoid process is medium-sized, anteriorly alveolar retraction and severe periodontal abrasion reaching inclined, in the range of grade 3. The supraorbital margin is the pulp chambers, as well as occlusal caries in the distal por- fine, slightly rounded, and elevated grade 4 in this scale (op. tion of the right premolar. Dental calculus is absent. In the 60 Figure 19.10  The Muknal individual. This skeleton was found in the deepest part of the Muknal cave, at a depth of 33 m, on a slightly elevated shelf about 0.5 m above the 65 cave floor within and partially overlying an extensive accumulation of charcoal. F C O P Y 408 PROO González et al. 66 Figure 19.11  Muknal skeleton. Basal view of the cranium. mandible all left molars, the second left premolar, left canine, However, Sac Aktun and Dos Ojos are flooded caves, sepa- all incisives, both right premolars, and the second and third rated, but technically “connected,” by partially water filled right molars were lost during the life of the individual. The caves. The total length of both caves (wet and dry) reaches remaining first left premolar and first right molar are worn 308.487 km (QRSS 2013:http://www.caves.org/project/qrss/ down and show occlusal caries in the right molar, extending qrdry.htm). into the pulp chamber. With a maximum depth of 130 m, Dos Ojos is one of The temporomandibular joints present arthrosis with the deepest cave systems on the Yucatan peninsula and the bone tissue reaction, principally on the left side. There is deepest known in Quintana Roo; it is therefore popular for a slight supra-inion injury on the left side with reaction on deep diving. Here we report on two partially preserved hu- the occipital. The right orbital roof presents a marked criba man skeletons from the Pat Jacinto cenote, also known as El 75 70 orbitalia, including remodeling of the bone tissue. A healed Pit (Figure 19.12). The cenote was first explored in 1994 by porotic hyperostosis is registered in the bregma region, while Kay Walten and Dan Lins. This cenote is located 4 km south of another reaction of the bone tissue was detected on the su- the Xel Ha inlet. It is reached from highway 307 via a dirt road perior margins of both auditive conducts, but primarily on at Dos Ojos Cenotes Park entrance that connects Cancun and the left side. Tulum. 71 Comments on the osteology Cenote Pat Jacinto (Previously Known as El Pit) 76 The cranium of the Muknal individual is ovoid in shape and The dispersed bones of at least two human individuals were thus corresponds to a mesocranial (for a definition of the discovered by unknown cave divers in the Pat Jacinto cenote craniometric indexes see Comas, 1966) morphology (78.48), and reported to us by cave-diving instructor Luis Leal. Both 77 with a narrow nose (leptorrin, 40.81) and low orbits (cam- remains form part of the debris mound of the cenote and econc, 82.92). In general terms, the cranium is bigger than were found in water depths of 30 to > 45 m. those of Naharon and Las Palmas, but within the range of the Bones as well as the taphonomic context have been de- 72 El Templo individual that was attributed to a male. On the graded by sulfuric acid in the water of Pat Jacinto cave, which other hand, the facial region, i.e., the narrow nose, resem- forms clouds at depths below approximately 35 m. Dissolu- bles the Naharon female, whereas the Las Palmas female has tion is strongest in the deep parts of the cenote, where cave 78 a wider nose. The low orbits are a common feature in all the sediment is in contact with water. Bone color is brown-yellow submerged cave individuals where this character is preserved on the coronal part, which was covered by sediment, and in Muknal, Las Palmas and possibly Naharon. lightly colored in parts exposed to the cave water. 73 Sac Actun system El Pit I 79 In 2012, the 82.291-km-long Dos Ojos system was reported The El Pit I individual consists of a fragmentary cranium dis- 74 by Peter Sprouse as forming part of the Sac Actun great sys- covered at a depth of 30 m. Postcranial material, which likely 80 tem, known to be 222.673 km long. The two systems are con- belongs to the same individual, is also included in the present nected by swamps, dry land, and partially water filled caves. preliminary description (Figure 19.13). F C O P Y 81 Sex PROO The First Human Settlers on the Yucatan Peninsula: Evidence from Drowned Caves auditive conducts, and the mastoid region up to the mastoid 409 The nucal crest is well developed, reaching grade 4 on the holes. The mastoid apophyses are fractured. The occipital is 82 scale developed by Buikstra and Ubelaker (1994). Even though broken in a paracoronal direction and at the height of the in- no other diagnostic elements are preserved, this character sertion of the Rect. Cap. Post Major and Minor, thus preserving suggests that the Pit I individual is a male. the external protuberance and a portion of the occipital crest. 83 Age Commentaries 89 In the absence of other characters, the low degree of fusion The Pit I cranium was discovered close to the entrance of of the cranial sutures suggests that the Pit I human was a the Pat Jacinto cave and forms part of the debris mound of young adult. The mandible, which likely belonged to the the cenote. In addition to the radiometric dating (see Table 84 same individual, shows the complete eruption of the third 19.2) of some of the human bones from this cenote, the cra- molar, even though dental abrasion is not very pronounced. nial morphology, even though incomplete, suggests that the 90 This reinforces the idea that the Pit I skeleton belonged to a Pit I skull differs from that of Mayan settlers by the absence young adult. of intentional cephalic deformation, a common character seen in about 80% of pre-Hispanic crania (Tiesler 2012), and 85 Pathology by its overall mesocranial shape, even though this interpre- We determined a small traumatic lesion recovered in life in tation needs to be substantiated by more detailed research. the frontal bone immediately above the left superciliary arch 86 and a slight exostosis affecting the upper margin of the right El Pit II 91 auditory canal. The El Pit II individual is composed of a parietal partially artic- ulated with the occipital, as well as on postcranial parts that 87 Conservation were discovered covering the debris mound of the El Jacinto 93 The encephalic portion of the cranium is preserved, but the cenote in water 44–45 m deep. These remains are presently total facial region and base are lost. The squama frontalis is under study, and only a preliminary description is given here. preserved above the glabella, but this is not enough to mea- sure the maximum length of the cranium. The sphenoid is Osteology 88 majorly lost, but small fractions adhering to the temporal are 94 A fragment of the left parietal preserves an almost complete preserved and indicate that the sphenotemporal sutures were occipital margin. In the lower edge the posterior region of 95 not fused yet. The temporal preserves mandibular pits, the the squamous border is preserved although the medium por- Figure 19.12  3-D sketch of the cenote Pat Jacinto, formerly known as El Pit. Note that the remains of two individuals when 92 discovered formed part of the debris mound of the cenote in water depths of 30 to >45 m. F C O P Y 410 PROO tion is missing, including the articulation with the sphenoids. González et al. increasing and presently comprises eight individuals. Bone Anteriorly, the coronal suture and the anterior half of the sag- material is majorly affected by post-depositional dissolution ittal suture are lost, even though the latter is well conserved processes, which modified the compact surface and spongy in its posterior half. The external diploe is little eroded, but bone and nearly completely degraded collagen, especially in its inner portion is majorly dissolved, as is the major part of shallow cave settings where the bone is exposed to fresh wa- the trabecular tissue. ter. This dissolution debilitates the cohesion of organic and 101 The second fragment corresponds to the occipital and inorganic portions of the bone and makes it vulnerable to conserves the left lambdoid suture, from Lambda to the fragmenting. It also hampers the use of radiometric C-14 dat- lateral angle and the superior part of the mastoid portion. ing methods because of widespread dissolution of a measur- From here, a fracture connects with the inferior curved line, able organic component (Taylor 2009) (Table 19.2). 96 raising the medial portion and running vertically to Lambda. Even in cases when radiometric data are absent, or sus- Consequently, the entire lower right portion of the occipital pect owing to insufficient collagen, the cranial morphology is missing, including the region around foramen magnum. of the cenote individuals is observably considerably different 102 The left parietal and the occipital articulate along the from pre- and post-Hispanic Maya. In addition, intentional 97 lambdoid suture, even though alignment is imprecise owing cephalic deformation seen in the majority of Mesoamerican to marginal dissolution in both bones. pre-Hispanic crania is absent (Tiesler 2012). The sex of the individual is yet undetermined, but some In a few cases, our research suggests that humans co- characteristics suggest its age at the moment of death: Cranial existed with Pleistocene animals. At La Chimenea (Figure sutures are widely open and preserve sharp margins, without 19.14), discovered by Steve Gerrard and Nancy de Rosa and 104 reported to one of us (J.A.), fossil bones of the camelid Hemi- auchenia macrocephala had been partially burned as a result 98 Figure 19.13  Underwater archaeologist collecting human skull fragment from 30 m deep at Cenote Pat Jacinto (formerly known as El Pit). any evidence of a fusion. The parietal is more rounded than in adult individuals of the research area. Inferior and superior 99 temporal lines are undeveloped, and in the occipital, muscu- lar incisions are shallow. We therefore preliminarily interpret the Pit II individual as an infant, or juvenile. 100 Discussion and Conclusions Figure 19.14  Bones of paleollama Hemiauchenia macrocephala collected at The database for human remains of Preceramic age in the La Chimenea site. Evidence suggests preceramic settlers may have eaten this 103 submerged caves of Quintana Roo, South Mexico, is steadily species. F C O P Y PROO The First Human Settlers on the Yucatan Peninsula: Evidence from Drowned Caves of roasting in an ancient hearth. The final extinction of Hemi- ogy is characterized by a narrow and low neurocranium, 411 auchenia in North America has been dated to 13,300–12,900 low orbits, and a wide nasal region (Neves and Hubbe 2005). cal yr BP (e.g., Haynes 2006; Fiedel and Haynes 2004), a pe- The face is generally low relative to the height of the neuro­ riod consistent with the extinction of other large mammals cranium, and the upper face region is unflattened. In the fos- found in the caves. The collapse of megafaunal populations sil record this morphology is present in extensive collections 110 may even have occurred between 14,800 and 13,700 cal yr from the Lagoa Santa region of Brazil, in the oldest human BP (Gill et al. 2009). remains from the Sabana de Bogotá region in Colombia, and Charcoal concentrations interpreted by us as hearths are in crania from the Mexican basin (González-José et al. 2005; also found in water depths of up to 30 m and were dated by Neves et al. 2007). Populations with these characteristics are 14 C to 8941 ± 39 yr BP and 7740 ± 39 yr BP at Las Palmas. known to exist up to the late Holocene in isolated regions of At Aktun Ha, discovered by J. Coke and reported to us by O. Patagonia and on southern Baja California (González-José et 105 Río, a small cavity in an isolated rock about 0.9 m above the al. 2003). cave ground had been used as a hearth. Charcoal samples The Amerindian morphology, on the other hand, is de- from this niche were dated by 14C to 9139 ± 23 yr BP and fined by bulged crania (brachicranial) and a wide and flat- 9180 ± 60 yr BP. Hearths clearly required a dry cave. tened face, principally in the medium and upper region 111 The cenote humans thus populated the area at a time (Pucciarelli 2004). These characters are found in almost all when caves reaching to 30 m and more below present water modern indigenous groups in the Americas (Pucciarelli 2004) level were still dry and unaffected by the post-Pleistocene and in mongoloid populations from China and other regions rise of sea level. It is known that present-day water levels of northern Asia (Cunningham and Jantz 2003). 106 were reached about 6600 yr BP (Blanchon and Shaw 1995; Ga- The dichotomous recognition of Paleoamerican and Am- briel et al. 2009). The corpses of these individuals could have erindian morphologies in ancient cultures of the American floated to their present locations, but this latter scenario ap- continent has led some authors to postulate a “two-compo- pears unlikely for the following reasons: nent model” (Pucciarelli 2004), in which the continent was 1) Human skeletons are found in deep parts of the caves, first colonized by groups emigrating from southern Asia. hundreds of meters from the nearest entrance. If the They would be the ancestors of modern “Australomelanesian” caves were water filled the corpses would have to drift groups and could have migrated to America along the Bering several hundreds of meters, through a cave system passage, approximately 12,000 years ago. Their cranio­facial 107 shape changed little and their demographic growth rate in of tunnels and open galleries decorated with spelo- themes, and be subsequently deposited almost com- America remained low. According to this model, the Paleo- plete (> 80% of bones were recovered). americans were replaced about 9000 years ago by a second migration wave of Amerindian groups. The replacement was 2) Four of the eight (El Templo, Las Palmas, Chan Hol I, 112 exceedingly fast and apparently occurred without genetic and Chan Hol II) were found almost fully articulated, interchange between the two cultural groups (Pucciarelly without major bone displacement, with even with the 2004). The model thus postulates that a clear discontinuity anatomical connections of carpals and tarsals intact. exists between the fossil remains of two distinct but homog- These structures are the first to disintegrate and slough enous human groups populating the same territories within off a body floating in water for a long time (Haglund the Americas: the Paleoamericans with a minimum age of and Sorg 2002). This situation clearly indicates the bod- 9000 years, and the Amerindians, which are younger. ies decayed in situ, which only could have occurred in Following this model, the Las Palmas, Naharon, Muknal a dry cave. Moreover, the flexed positions of the Naha- and El Pit individuals would be of Paleoamerican genetic stock 108 ron, Las Palmas, Chan Hol I, and Chan Hol II, and pos- and thus should resemble fossil humans from the Mexican sibly Muknal individuals were intentionally deposited, basin, Lagoa Santa, as well as modern Australomelanesian likely in a funeral, which would also require a place that groups, and they should differ from historic and modern Ma- was dry at the time. At El Pit I and El Templo this situa- yan populations. This is only partially the case: Even though tion is less clear. The final disposition of the skeletons cranially diverse, the preceramic individuals from the Yucatan 113 appears to be the result of accidental death in the case submerged caves are indeed characterized by mesocrania of El Templo, and water-run-off for El Pit I. with low orbits, narrow faces and variable nose apertures, Human skeletons from the drowned caves of the Yucatan whereas Maya populations from the same region present a peninsula are dated to the Pleistocene-Holocene transition marked hyperbrachycephaly (very rounded skulls), hypso- to and are thus among the earliest settlers of the American con- orthocrania hipertapeinocrania (wide, short and low skulls), tinent known from bone material. The physical morphology and facial regions eurienas (broad), mesorrinas (intermedi- 109 of their crania should give evidence for their evolutionary re- ate nose width), hipsoconcs (low orbits) and mesognats (flat lationship with subsequent settlers in the area such as the faces) (Tiesler 2012). These differences, however, are not suf- pre-Hispanic cultures that populated Mesoamerica during the ficiently pronounced to exclude the possibility that the late- middle and late Holocene. Pleistocene individuals may indeed be ancestors of the pre- In this context, the so-called Paleoamerican morphol- Hispanic Maya. F C O P Y 412 PROO As a minimum, although the Las Palmas, Naharon and González et al. royo, Oscar Polaco†, Paul Blanchon. Luis Marín, Elva Escobar, Muknal individuals show important inconsistencies within Magdalena de los Ríos, Erv Taylor, Alistair Pike, Thomas High- the so-called Paleoamerican morphology, nonetheless they man, Silvia González, José C. Jiménez, Mónica López Portillo, do not coincide with Amerindians either. The individu- Carlos Serrano, Pilar Luna, Fernando Sánchez, Sergio Grose- als from submerged caves have mesocranial skulls, with an jan, Felipe Bate, Ximena Chávez, Fidencio Rojas, Aldo Castro, overall shape and size outside the dimensions of the Lagoa Rodrigo González, Susana Xelhuatzin, Paolo Testelli, and Fro- Santa, Sabana de Bogotá, and Basin of Mexico collections. ylan Rojas. Lisseth Pedroza, Sandra Damián, Raúl Cervantes, They ­ rather resemble other early-Holocene skulls from Esther Reynoso, and Lucía Ivonne Lopez were students who North America, such as those from Pelican Rapids, Florida; participated in the fieldwork. We gratefully appreciate the Gordon Creek, Colorado; Marmes, Washington (Young and detailed revision and comments by editors Kelly Graf and 114 Steele 1987); and Buhl, Idaho (Herrmann et al. 2006), all of Caroline Ketron and by two anonymous reviewers. We spe- which are mesocranial and show a greater variability than cially thank Miguel Quintana and Grupo Xcaret. We acknowl- their counterparts from South America (multivariate analysis edge support of the project “Atlas Arqueológico Subacuático 118 shows clearly the variability of “Paleoamerican” individuals para el Registro, Estudio y Protección de los Cenotes en la from North America; Terrazas et al. in preparation). Península de Yucatán” and “Estudio de los grupos humanos These preliminary results suggest that near the end of preceramicos de la costa oriental de Quintana Roo, México, a the Pleistocene a notable morphological diversity must al- través de los contextos actualmente inundados” by the Insti- ready have existed, which was likely the result of local micro- tuto Nacional de Antropología e Historia (INAH) and financial evolution. The early colonization of North and South America support by the Internationales Büro of the German Bundes- 115 must have been a highly complex process in which disper- ministerium für Forschung und Wissenschaft (BMBF project sion and adaptation to local environments are not fully un- 01DN119), the Rolex Award for Enterprise 2008, Dive Xtras derstood. diver propulsion vehicles and by GEO Magazine. The latest-Pleistocene to early-Holocene ages of the Quintana Roo individuals and their marked cranial diversity, References Cited combined with the diversity known to date for other North Back, W.  1985  Hydrogeology of the Yucatán. In Geology and Hy- American “Paleoamerican” skulls, provide evidence for an drogeology of Northeastern Yucatán and Quaternary Geology of North- early colonization of the Americas, which likely occurred eastern Yucatan, edited by C. Ward, A. E. Weidie, and W. Back, pp. 99–124. New Orleans Geological Society. 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