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DIRECT DATING OF THE HUMAN NAVICULAR FROM THE CUEVA DE LOS TORREJONES (GUADALAJARA, SPAIN)
- Adrián Pablos, Nohemi Sala, Alfonso Arribas
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- Journal:
- Radiocarbon / Volume 63 / Issue 1 / February 2021
- Published online by Cambridge University Press:
- 23 September 2020, pp. 213-222
- Print publication:
- February 2021
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Pleistocene human remains are rare inland on the Iberian Peninsula. Most are considered Neandertals, but anthropological analyses and direct dating are rare. Recently, we published a study of a navicular from this region found in the Torrejones Cave. The results showed it differed from that of Neandertals and it was re-identified as Homo sapiens. Following the previous stratigraphic and biochronologic descriptions, we suggested that it could correspond to an Upper Paleolithic human, since the navicular was apparently recovered in the Late Pleistocene from an in situ unit. Direct radiocarbon dating from this fossil (4855–5036 cal BP), believed to be the only Paleolithic Homo sapiens from inland Iberia, as well as other hominin and faunal remains from the site, show that the human bones actually date to the Chalcolithic. The unexpectedly recent chronology for the navicular implies that there is no evidence of human fossils from the Upper Paleolithic in Torrejones Cave. Thus, any date from the Middle/Upper Paleolithic human record should be taken with caution until in-depth paleoanthropological, stratigraphical and/or direct dating studies are conducted. Extraordinary caution is recommended when human remains are recovered from apparently Paleolithic units in contexts bearing Holocene sepulchral units on the uppermost levels and/or some evidence of bioturbation.
Taphonomic decoding of the paleobiological information locked in a lower Pleistocene assemblage of large mammals
- Paul Palmqvist, Alfonso Arribas
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- Journal:
- Paleobiology / Volume 27 / Issue 3 / Summer 2001
- Published online by Cambridge University Press:
- 08 April 2016, pp. 512-530
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The processes of fossilization have usually been perceived by paleontologists as destructive ones, leading to consecutive (and in most cases irretrievable) losses of paleobiological information. However, recent developments of conceptual issues and methodological approaches have revealed that the decrease in paleobiological information runs parallel to the gain of taphonomic information. This taphonomic imprinting often makes it possible to decode the fraction of paleobiological information that was lost during fossilization, and may also contribute new data for deciphering paleobiological information that was not originally preserved in the assemblage, such as paleoethology. A good example is the study of the macrovertebrate assemblage from the lower Pleistocene site at Venta Micena (Orce, southeastern Spain). Taphonomic analysis showed that the giant, short-faced hyenas (Pachycrocuta brevirostris) selectively transported ungulate carcasses and body parts to their maternity dens as a function of the mass of the ungulates scavenged. The fracturing of major limb bones in the dens was also highly selective, correlating with marrow content and mineral density. Important differences in bone-cracking intensity were related to which species the bones came from, which in turn biased the composition of the bone assemblage. The analysis of mortality patterns deduced for ungulate species from juvenile/adult proportions revealed that most skeletal remains were scavenged by the hyenas from carcasses of animals hunted by hypercarnivores, such as saber-tooths and wild dogs. Analytical study of the Venta Micena assemblage has unlocked paleobiological information that was lost during its taphonomic history, and has even provided paleobiological information that was not preserved in the original bone assemblage, such as the paleoethology of P. brevirostris, which differed substantially from modern hyenas in being a strict scavenger of the prey hunted by other carnivores.
Prey selection by terrestrial carnivores in a lower Pleistocene paleocommunity
- Paul Palmqvist, Bienvenido Martínez-Navarro, Alfonso Arribas
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- Journal:
- Paleobiology / Volume 22 / Issue 4 / Fall 1996
- Published online by Cambridge University Press:
- 08 April 2016, pp. 514-534
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We report quantitative paleoecologic data on the large mammal assemblage preserved in lower Pleistocene deposits at Venta Micena (Orce, Granada, southeastern Spain). Taphonomic studies show that bones were collected mainly by hyaenids, which transported and deposited them near shallow dens. Differential fragmentation of major long bones was produced by hyaenas as a function of their density and marrow content. Strong selection of prey by carnivores—which preferentially killed juveniles, females, and individuals with diminished locomotor capabilities among ungulate prey species of larger body size—is indicated by (1) the abundance of remains of juvenile ungulates in relation to the average weight of adult individuals in each species, (2) attritional mortality profiles for ungulate species deduced from crown height measurements, (3) the presence of many metapodials with different osteopathologies in their epiphyses, such as arthrosis, and (4) a biased intersexual ratio of large bovids. Comparison of the frequencies with which modern African carnivores kill and scavenge ungulates from various size classes with the abundance of these size categories in the assemblage suggests that the Venta Micena hyaena (Pachycrocuta brevirostris) was a bone-cracking scavenger that fed largely on carcasses of ungulates preyed upon and partially consumed by fresh meat-eating carnivores such us saber-toothed felids (Homotherium latidens and Megantereon whitei) and wild dogs (Canis falconeri).
Paleoecological reconstruction of a lower Pleistocene large mammal community using biogeochemical (δ13C, δ15N, δ18O, Sr:Zn) and ecomorphological approaches
- Paul Palmqvist, Darren R. Gröcke, Alfonso Arribas, Richard A. Fariña
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- Journal:
- Paleobiology / Volume 29 / Issue 2 / Spring 2003
- Published online by Cambridge University Press:
- 08 April 2016, pp. 205-229
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Ecomorphological and biogeochemical (trace element, and carbon, nitrogen, and oxygen isotope ratios) analyses have been used for determining the dietary niches and habitat preferences of large mammals from lower Pleistocene deposits at Venta Micena (Guadix-Baza Basin, Spain). The combination of these two approaches takes advantage of the strengths and overcome the weakness of both approaches. The range of δ13Ccollagen values for ungulate species indicates that C3 plants were dominant in the diet of these mammals. δ13Ccollagen values vary among ungulates: perissodactyls have the lowest values and bovids the highest ones, with cervids showing intermediate values. The hypsodonty index measured in lower molar teeth and the relative length of the lower premolar tooth row indicate that the horse, Equus altidens, was a grazing species, whereas the rhino, Stephanorhinus etruscus, was a mixed feeder in open habitats. The similar δ13Ccollagen values shown in both perissodactyls does not reflect differences in feeding behavior with other ungulates, but rather a lower isotope enrichment factor in these monogastric herbivores than in ruminants, owing to their lower metabolic efficiency. The cervids Eucladoceros giulii and Dama sp. show low hypsodonty values, indicating that they were mixed feeders or browsers from forested habitats, an ecomorphologically based conclusion corroborated in the former by its low δ15Ncollagen content (canopy effect). Bovid species (Bovini aff. Leptobos, Soergelia minor, and Hemitragus albus) presumably inhabited open environments, according to their comparatively high hypsodonty and δ15Ncollagen values. Carnivore species (Homotherium latidens, Megantereon whitei, Pachycrocuta brevirostris, Canis falconeri, and Canis etruscus) exhibit higher δ15Ncollagen values than ungulates. These results record the isotopic enrichment expected with an increase in trophic level and are also supported by low bone Sr.Zn ratios. The elevated δ15Ncollagen value for a sample of Mammuthus meridionalis, which came from an individual with unfused epiphyses, confirms that it was a suckling animal. The δ15Ncollagen value of the scimitar-cat H. latidens is well above that obtained for the young individual of Mammuthus, which indicates that juvenile elephants were an important part of its diet. The hippo, Hippopotamus antiquus, yielded unexpectedly high δ15Ncollagen values, which suggest feeding on aquatic, non-N2-fixing plants. The high δ18Ohydroxyl values of bovids Hemitragus and Soergelia and of cervid Dama indicate that these ungulates obtained most of their water requirements from the vegetation. The megaherbivores and Eucladoceros exhibit the lowest δ18Ohydroxyl values, which suggest increased water dependence for them. Paleosynecological analysis was based on the relative abundance of species of large mammals from different ecological categories, determined by feeding behavior and locomotion types. The comparison of the frequencies of such categories in Venta Micena with those found in modern African communities indicates that the composition of the paleocommunity closely resembles those of savannas with tall grass and shrubs. The net above-ground primary productivity estimated for the on-crop biomass of the mammalian species preserved in the fossil assemblage also yields a figure congruent with that expected for an open environment.