The endemic bovids from Sardinia and the Balearic Islands: State of the art

Bovids are not so common in endemic insular faunas and are mainly recorded in Southeast Asia, Japan and some Mediterranean islands. In the Western Mediterranean, endemic bovids have been recorded during the late Miocene in the Tusco-Sardinian palaeobioprovince (Baccinello-Cinigiano basin, South Tuscany, and Fiume Santo, north-western Sardinia). In the latest Neogene and Quaternary, bovids showing highly endemic features were restricted to the Balearic Islands and Sardinia, while Bovini only slightly reduced in size were present on Pianosa, Malta and Sicily. On Sardinia, the richest bovid sample comes from Monte Tuttavista (Orosei), where at least three species have been identified: Asoletragus genthry, Nesogoral aff. N. melonii, and Nesogoral sp. 2. On Mallorca (Balearic Islands) six chronospecies belonging to the Myotragus endemic phylogenetic lineage have been described, spreading in age from the Early Pliocene to the Holocene. For decades, a close phylogenetic relationship between Nesogoral and Myotragus has been widely accepted by scholars. Morphological and biometrical differences shown by Balearic and Sardinian bovids have generally been regarded as the result of the evolution into two different island ecological systems, characterized by different inter and intra-guild selection pressures. Indeed, the more diversified environment of Sardinia, as well as the presence of other large mammals (similar-sized competitors belonging to the same guild and a running predator), increased the interspecific competition, forcing Sardinian bovids to exploit different resources and to occupy different niches, while Myotragus exploited under a monopoly regime the supply of resources available for large herbivores on the Eastern Balearic Islands. Nonetheless, new data suggest that Nesogoral and Myotragus possibly originated from different taxa.     

Biocomplexity and conservation of biodiversity hotspots: three case studies from the Americas

The perspective of 'biocomplexity' in the form of 'coupled natural and human systems' represents a resource for the future conservation of biodiversity hotspots in three direct ways: (i) modelling the impact on biodiversity of private land-use decisions and public land-use policies, (ii) indicating how the biocultural history of a biodiversity hotspot may be a resource for its future conservation, and (iii) identifying and deploying the nodes of both the material and psycho-spiritual connectivity between human and natural systems in service to conservation goals. Three biocomplexity case studies of areas notable for their biodiversity, selected for their variability along a latitudinal climate gradient and a human-impact gradient, are developed: the Big Thicket in southeast Texas, the Upper Botanamo River Basin in eastern Venezuela, and the Cape Horn Archipelago at the austral tip of Chile. More deeply, the biocomplexity perspective reveals alternative ways of understanding biodiversity itself, because it directs attention to the human concepts through which biodiversity is perceived and understood. The very meaning of biodiversity is contestable and varies according to the cognitive lenses through which it is perceived.     

The Neolithic transition in Europe and North Africa. The functional craneology contribution

The origin and mode of the process that led to food production in Europe and North Africa is a matter intensively discussed. It is not clear in the transition to the Neolithic in these regions if it results by a migration of peoples from the Near East, by changes in the behaviour of local populations, or by an interaction of both processes. Morphological changes in Europe and North Africa, from the Upper Palaeolithic to modern periods were assessed. A method based on the Functional Matrix Hypothesis was carried out, which implies that the bone shape is modified by the related soft tissues. Absolute and relative size and shape changes were estimated on two major--neural and facial--and eight minor--anteroneural, midneural, posteroneural, otic, optic, respiratory, masticatory and alveolar--functional cranial components (FCC). ANOVA and Canonical Correlation analyses indicate that neither a temporal trend nor a pattern characteristic of each region is evidenced. But a shift is observed between the Upper Palaeolithic groups and the later samples. Size is greater in the Upper Palaeolithics. Shape is modified because Upper Palaeolithics have greater midneural and masticatory FCCs, and smaller optic FCC. The greater masticatory volume is associated to wider faces in hunter-gatherers. Our study cannot enable to conclude if the morphological shift is caused by a replacement or by a change in the local populations, however, the morphological changes can be attributed to the reduced mobility and the masticatory stress since the Neolithic period.     

Different cranial ontogeny in Europeans and Southern Africans

Modern human populations differ in developmental processes and in several phenotypic traits. However, the link between ontogenetic variation and human diversification has not been frequently addressed. Here, we analysed craniofacial ontogenies by means of geometric-morphometrics of Europeans and Southern Africans, according to dental and chronological ages. Results suggest that different adult cranial morphologies between Southern Africans and Europeans arise by a combination of processes that involve traits modified during the prenatal life and others that diverge during early postnatal ontogeny. Main craniofacial changes indicate that Europeans differ from Southern Africans by increasing facial developmental rates and extending the attainment of adult size and shape. Since other studies have suggested that native subsaharan populations attain adulthood earlier than Europeans, it is probable that facial ontogeny is linked with other developmental mechanisms that control the timing of maturation in other variables. Southern Africans appear as retaining young features in adulthood. Facial ontogeny in Europeans produces taller and narrower noses, which seems as an adaptation to colder environments. The lack of these morphological traits in Neanderthals, who lived in cold environments, seems a paradox, but it is probably the consequence of a warm-adapted faces together with precocious maturation. When modern Homo sapiens migrated into Asia and Europe, colder environments might establish pressures that constrained facial growth and development in order to depart from the warm-adapted morphology. Our results provide some answers about how cranial growth and development occur in two human populations and when developmental shifts take place providing a better adaptation to environmental constraints.     

East-West cranial differentiation in pre-Columbian populations from Central and North America

In a recent study we found that crania from South Amerindian populations on each side of the Andes differ significantly in terms of craniofacial shape. Western populations formed one morphological group, distributed continuously over 14,000km from the Fuegian archipelago (southern Chile) to the Zulia region (northwestern Venezuela). Easterners formed another group, distributed from the Atlantic Coast up to the eastern foothills of the Andes. This differentiation is further supported by several genetic studies, and indirectly by ecological and archaeological studies. Some authors suggest that this dual biological pattern is consistent with differential rates of gene flow and genetic drift operating on both sides of the Cordillera due to historical reasons. Here we show that such East-West patterning is also observable in North America. We suggest that the "ecological zones model" proposed by Dixon, explaining the spread of the early Americans along a Pacific dispersal corridor, combined with the evolution of different population dynamics in both regions, is the most parsimonious mechanism to explain the observed patterns of within- and between-group craniofacial variability.     

Three levels of integrating ecology with the conservation of South American temperate forests: the initiative of the Institute of Ecological Research Chiloé, Chile

The diversity of native species assemblages and that of indigenous cultures that once characterized the temperate forests of southern Chile have experienced a process of homogenization ever since the Spanish conquest. Today this process continues to erode both biotic and cultural diversity. With the goal of linking ecological research with actions to conserve the biological and cultural richness of this region, we established the Institute of Ecological Research Chiloé. The Institute's philosophy and activities involve three approaches: (1) participation of professional ecologists in environmental education and decision making, through collaboration with the community at local, regional, and global scales. (2) programs of ecological education, which include planting indigenous trees in urban areas and creating a local botanical garden with representative Chilean forest species. (3) critical analyses of the narrow economic and utilitarian environmental ethics that currently prevail in Chile, and often in other Latin American nations, and examination of traditional or novel alternative ethics and perspectives that address multiple interrelations between biological and cultural dimensions.     

Computation of physicochemical parameters, namely pH, in complex (bio)chemical systems: extension to gas-liquid systems

The first model has been proposed to compute, in complex liquid (bio)chemical systems, a number of physicochemical parameters, namely pH, concentration of one of any chemical species, partition between acid-base forms, global charge, or ionic strength, assuming the physicochemical equilibrium state. The extension of the present model, described here, permits moreover the computation of gas-liquid distributions, specific gas volumes, or total pressures. The model solely requires the knowledge of existing thermodynamic constants and of the concentration of every chemical species other than the species under examination. The model elicits a unique equilibrium state. Computed values agreed with experimental measurements, thereby validating the model. Digital computer programs were prepared to use the proposed algorithms.     

Acetoclastic methanogenic activity measurement by a titration bioassay.

A titration bioassay, designed to accurately determine the activity of acetoclastic methanogens, is described that also allows evaluation of inhibition due to potential toxicants on the active biomass. The instrument is made of a pH-stat connected to an anaerobic batch reactor. Acetate is blended and mixed with anaerobic sludge in the reactor where a 1:1 N2 and CO2 mixture is sparged at the beginning of each test. As the acetoclastic methanogens consume acetate, the pH increase, and the titration unit adds acetic acid and keeps the pH constant. The rate of titrant addition is directly proportional to the methanogenic activity. A very useful feature of the system is its potential to operate for long periods (days) at constant pH and substrate (acetate) concentration. The theoretical background and principle of operation are described as well as some of the practical problems encountered with the use of the instrument. Estimation of kinetic constants for an anaerobic culture according to the Michaelis-Menten model is presented. Examples of inhibition by inorganics (NaCl) and chlorinated solvents (chloroform) are also given.     

Variation of functional cranial components in six Anthropoidea species

Sixty male crania from three Platyrrhini and three Catarrhini genera were measured by means of the craniofunctional method. The aim was to analyze functional components of the skull and relate their function and the degree of encephalization to life history variables. We recognized two major and eight minor functional components. The objectives were to test (1) if within-taxa (Platyrrhini or Catarrhini) and/or between-taxa (Platyrrhini and Catarrhini) comparisons showed minor-component differentiation; and (2) if encephalization affects both primate groups differently. After standardization by size and scaling, 15 possible within-taxa and between-taxa comparisons were made. We found a strong phylogenetic signal, i.e., cranial differences were not randomly distributed, with the between-taxa variation being greater than within-taxa. Both hypotheses tested were accepted since: (1) There was no random variation between functional cranial components. They followed definite patterns for ancestral and derived traits. (2) Encephalization was present in all scaled comparisons, with Platyrrhini showing a higher degree of encephalization than Catarrhini. We conclude that major and minor craniofunctional components should be considered as correlated traits related to life history, because we found different patterns between platyrrhines and catarrhines, and within species of both taxa.