Exploring the Potential of Laser Ablation Carbon Isotope Analysis for Examining Ecology during the Ontogeny of Middle Pleistocene Hominins from Sima de los Huesos (Northern Spain).

Nuria Garcia,Benjamin H Passey,Juan Luis Arsuaga,Thure E Cerling,Robert S Feranec,Luca Bondioli

doi:10.1371/journal.pone.0142895

Abstract

Laser ablation of tooth enamel was used to analyze stable carbon isotope compositions of teeth of hominins, red deer, and bears from middle Pleistocene sites in the Sierra de Atapuerca in northern Spain, to investigate the possibility that this technique could be used as an additional tool to identify periods of physiological change that are not detectable as changes in tooth morphology. Most of the specimens were found to have minimal intra-tooth variation in carbon isotopes (< 2.3‰), suggesting isotopically uniform diets through time and revealing no obvious periods of physiological change. However, one of the two sampled hominin teeth displayed a temporal carbon isotope shift (3.2‰) that was significantly greater than observed for co-occurring specimens. The δ13C value of this individual averaged about -16‰ early in life, and -13‰ later in life. This isotopic change occurred on the canine crown about 4.2 mm from the root, which corresponds to an approximate age of two to four years old in modern humans. Our dataset is perforce small owing to the precious nature of hominid teeth, but it demonstrates the potential utility of the intra-tooth isotope profile method for extracting ontogenetic histories of human ancestors.

Highlights

The hominins recovered from the Sima de los Huesos (SH) in the Sierra de Atapuerca (Spain) represent a majority (>80%) of the global fossil record for the genus Homo in the middlePLOS ONE | DOI:10.1371/journal.pone.0142895 December 16, 2015Laser Ablation Carbon Isotopes of Sima de los Huesos HomininsPleistocene
The most positive mean δ13C value for an individual was observed in Cervus elaphus, while the most negative individual mean value was observed in the hominin specimens
Previous analysis of hominin fossils from the middle Pleistocene Sima de los Huesos locality of northern Spain showed a limited percentage of hypoplasias among the hominin population at this locality, possibly indicating that the hominins were well adapted to the environment [20,21]

Summary

Introduction

The hominins recovered from the Sima de los Huesos (SH) in the Sierra de Atapuerca (Spain) represent a majority (>80%) of the global fossil record for the genus Homo in the middle. The abundance of hominin specimens here (Number of Identified Specimens = >6500) provides a unique opportunity to examine specific aspects of hominin development and ecology during the middle Pleistocene Topics such as the timing of behavioral or developmental changes within a hominin population may be addressed, while there may be little power to elucidate such subjects at sites with more limited hominin remains. We explore the possibility that stable isotope analysis can identify significant changes in diet, and, subsequently, whether these changes can be related to particular ontogenetic events (e.g., weaning) as was suggested for the majority of hypoplasias in the SH hominins [21]

Background and Methods

Results and Discussion

Conclusions