Ferran Estebaranz

Buccal dental microwear variability in extant African Hominoidea: taxonomy versus ecology

Buccal microwear patterns on teeth are good indicators of the abrasiveness of foodstuffs and have been used to trace the dietary habits of fossil species, including primates and hominids. However, few studies have addressed the variability of this microwear. The abrasiveness of dietary components depends not only on the hardness of the particles ingested, but also on the presence of dust and other exogenous elements introduced during food processing. These elements are responsible for the microwear typology observed on the enamel surfaces of primate teeth. Here we analyzed the variability of buccal microwear patterns in African Great Apes (Gorilla gorilla and Pan troglodytes), using tooth molds obtained from the original specimens held in several osteological collections. Our results suggest that ecological adaptations at subspecies or population level account for differences in microwear patterns, which are attributed to habitat and ecological conditions within populations rather than differences between species. The findings from studies on the variability of buccal dental microwear in extant species will contribute to a better understanding of extinct hominids’ diet and ecology.

Testing hypotheses of dietary reconstruction from buccal dental microwear in Australopithecus afarensis.

A recent study of occlusal microwear in Australopithecus afarensis described this species as an opportunistic dweller, living in both forested and open environments and greatly relying on fallback resources and using fewer food-processing activities than previously suggested. In the present study, analysis of buccal microwear variability in a sample of A. afarensis specimens (n=75 teeth) showed no significant correlations with the ecological shift that took place around 3.5Ma in Africa. These results are consistent with the occlusal microwear data available. In fact, significant correlations between buccal and occlusal microwear variables were found. However, comparison of the buccal microwear patterns showed clear similarities between A. afarensis and those hominoid species living in somewhat open environments, especially the Cameroon gorillas. A diet based mainly on succulent fruits and seasonal fallback resources would be consistent with the buccal microwear patterns observed.

Buccal dental microwear analyses support greater specialization in consumption of hard foodstuffs for Australopithecus anamensis

Molar occlusal microwear texture and anisotropy analyses of 3 Australopithecus anamensis fossil specimens have shown complexity values similar to those of Au. afarensis, indicating that neither of these hominin species had a diet dominated by hard food. However, many researchers have suggested that these were some of the earliest hominins to have such diets. Here we examine buccal microwear patterns of 5 Au. anamensis, 26 Au. afarensis, 48 Hominoidea and 80 Cercopithecoidea primate specimens for independent evidence of dietary adaptations of Au. anamensis. The buccal microwear results obtained suggest that the diet of Au. anamensis relied heavily on hard, brittle food, at least seasonally. This is similar to the diet of the extant Cercopithecoidea primates, including Papio anubis and Chlorocebus aethiops, both of which live in wooded, seasonal savannah environments and have diets that include fruit and grasses, but also underground storage organs (USOs), such as corms or blades, as well as leaves and seeds, and also Mandrillus and Cercocebus, from forested environments with frugivorous-granivorous diets. Furthermore, the buccal microwear patterns of Au. anamensis and Au. afarensis clearly differed - in clear contrast to occlusal enamel texture observations-, which support previous dietary interpretations based on both anatomical and palaeocological reconstructions.

3-D interferometric microscopy applied to the study of buccal enamel microwear

Dental microwear analysis is based on the assumption that a correlation exists between ingested diet and microwear patterns on the enamel surface of teeth, such that diet can be reconstructed by quantifying enamel microwear. Abrasive particles, such as plant phytoliths or silica-based sands incorporated into food items, along with food processing techniques and tooth morphology, are responsible for the microwear features observed. Dental microwear has been extensively studied in both extant and extinct primates, including human populations. The dietary and ecological information that can be derived from dental microwear analyses makes it a technique useful for analyzing non-primate species, such as muskrats, sheep, bats, moles, antelopes, pigs and even dinosaurs. In the attempt to reconstruct species’ ecology and diet, microwear research has become a successful procedure. The proliferation and persistence of different methods to quantify microwear patterns require very accurate definitions of microwear variables, since inter-observer error rates cannot be neglected. The use of semiautomatic methods to quantify microwear features does not guarantee low inter-observer error affecting dental microwear results. Error can be caused by taphonomy, microscopy drawbacks of back-scattered electrons, or differences in SEM reproducibility depending on sample shape and orientation. However, fully automatic procedures lack discrimination between ante-mortem and post-mortem wear processes that affect tooth enamel at various degrees, and their application requires experienced control and evaluation.

Goal Oriented Soil Mapping: Applying Modern Methods Supported by Local Knowledge

Abstract Soil mapping is very important for the correct implementation of sustainable land use management. In recent decades, soil mapping methods and data availability have increased exponentially, improving the quality of the maps produced. Despite these advances, local knowledge is a great source of information, refined for centuries and useful for soil mapping and the implementation of a sustainable land management. Local wisdom and experience should be an important aspect of soil mapping because farmers will be one of the major end-users of the maps produced and they should account for the farmers’ reality. However, several problems have been identified in the spatial correlation between folk and scientific classification related to different cultural variables that influence local soil classification.