Dental wear patterns reveal dietary ecology and season of death in a historical chimpanzee population

Dental wear analyses have been widely used to interpret the dietary ecology in primates. However, it remains unclear to what extent a combination of wear analyses acting at distinct temporal scales can be beneficial in interpreting the tooth use of primates with a high variation in their intraspecific dietary ecology. Here, we combine macroscopic tooth wear (occlusal fingerprint analysis, long-term signals) with microscopic 3D surface textures (short-term signals) exploring the tooth use of a historical western chimpanzee population from northeastern Liberia with no detailed dietary records. We compare our results to previously published tooth wear and feeding data of the extant and continually monitored chimpanzees of Taї National Park in Ivory Coast. Macroscopic tooth wear results from molar wear facets of the Liberian population indicate only slightly less wear when compared to the Taї population. This suggests similar long-term feeding behavior between both populations. In contrast, 3D surface texture results show that Liberian chimpanzees have many and small microscopic wear facet features that group them with those Taї chimpanzees that knowingly died during dry periods. This coincides with historical accounts, which indicate that local tribes poached and butchered the Liberian specimens during dust-rich dry periods. In addition, Liberian females and males differ somewhat in their 3D surface textures, with females having more microscopic peaks, smaller hill and dale areas and slightly rougher wear facet surfaces than males. This suggests a higher consumption of insects in Liberian females compared to males, based on similar 3D surface texture patterns previously reported for Taї chimpanzees. Our study opens new options for uncovering details of feeding behaviors of chimpanzees and other living and fossil primates, with macroscopic tooth wear tracing the long-term dietary and environmental history of a single population and microscopic tooth wear addressing short-term changes (e.g. seasonality)

Dental wear at macro- and microscopic scale in rabbits fed diets of different abrasiveness: A pilot investigation

To differentiate the effects of internal and external abrasives on tooth wear, we performed a controlled feeding experiment in rabbits fed diets of varying phytolith content as an internal abrasive and with addition of sand as an external abrasive. 13 rabbits were each fed one of the following four pelleted diets with different abrasive characteristics (no phytoliths: lucerne L; phytoliths: grass G; more phytoliths: grass and rice hulls GR; phytoliths plus external abrasives: grass, rice hulls and sand GRS) for two weeks. At the end the feeding period, three tooth wear proxies were applied to quantify wear on the cheek teeth at macroscopic and microscopic wear scales: CT scans were obtained to quantify tooth height. Mesowear was scored adapted to this species, and 3D dental microwear texture analysis (DMTA) was performed on four antagonistic teeth. Both external and internal abrasives resulted in increased wear in all proxies compared to the phytolith and sand-free diet (L). The wear effect was more prominent on the maxillary than on the mandibular teeth. On the GRS diet, the upper third premolar had the largest decline in relative tooth height compared to others in the same tooth row. The impact of diet abrasiveness on the mesowear signal was only clearly visible for the most abrasive diet, most likely due to the limited sample size. DMTA was especially sensitive to phytolith changes in the diet, and surface roughness generally increased with increasing amounts of abrasive agents (L < G < GR < GRS) as expressed in an increase of most height and volume parameters. The fast pace of dental wear in this species led to some expected correlations between tooth height, mesowear and DMTA parameters, creating a distinct wear pattern for each diet. Animal models with high wear rates may be particularly suitable for investigations on functional interrelationships of different wear proxies

Tooth wear patterns in black rats (Rattus rattus) of Madagascar differ more in relation to human impact than to differences in natural habitats

Dietary characteristics and environmental variables are important selective factors directing ecological diversification in rodents. On Madagascar, the introductions and spread of the commensal black rat (Rattus rattus) can be seen as example cases to study dietary niche occupation and dietary adaptation in an insular environment. We investigate how tooth wear as a measure of dietary adaptation of black rats differs between four distinct habitats (village, manioc fields, spiny forest, and rainforest) with different dietary resources. We use the 3D surface texture analysis (3DST, using 30 parameters according to ISO 25178) as a measure of dietary abrasiveness. 3DST is applied on the occlusal surface of the upper first molar of 37 black rat specimens. The rainforest sample displays less rough and less voluminous surface textures compared to the village samples as indicated by smaller values for height parameters (Sa, Sp, Sq), inverse areal material ratio (Smc), and volume parameters (Vm, Vmc, Vmp, Vv, and Vvc). We therefore rank sampling areas from highest to lowest abrasiveness (village>manioc fields/spiny forest>rainforest). The rats from villages and rainforest differ to such an extent that one could have interpreted them to belong to different species. This indicates a high degree of variability in terms of ingesta abrasiveness. Furthermore, the pronounced difference between rats from human habitations compared to rats from associated fields or natural vegetation is interpreted to clearly indicate shifts in dietary niche occupation in relation to human impact

Inclusive production of charged pions in p+C collisions at 158 GeV/c beam momentum

The production of charged pions in minimum bias p+C interactions is studied using a sample of 377000 inelastic events obtained with the NA49 detector at the CERN SPS at 158 GeV/c beam momentum. The data cover a phase space area ranging from 0 to 1.8 GeV/c in transverse momentum and from -0.1 to 0.5 in Feynman x. Inclusive invariant cross sections are given on a grid of 270 bins per charge thus offering for the first time a dense coverage of the projectile hemisphere and of the cross-over region into the target fragmentation zone.Comment: 31 pages, 30 figures, submitted to European Journal of Physic

Multiplicity fluctuations in nuclear collisions at 158 A GeV

System size dependence of multiplicity fluctuations of charged particles produced in nuclear collisions at 158 A GeV was studied in the NA49 CERN experiment. Results indicate a non-monotonic dependence of the scaled variance of the multiplicity distribution with a maximum for semi-peripheral Pb+Pb interactions with number of projectile participants of about 35. This effect is not observed in a string-hadronic model of nuclear collision HIJING.Comment: Presented at "Focus on Multiplicity", 17-19 of June, Bari, Ital

Bose-Einstein correlations of pion pairs in central Pb+Pb collisions at CERN SPS energies

Measurements of Bose-Einstein correlations of pion pairs in central Pb+Pb collisions were performed with the NA49 detector at the CERN SPS for beam energies of 20A, 30A, 40A, 80A, and 158A GeV. Correlation functions were measured in the longitudinally co-moving ``out-side-long'' reference frame as a function of rapidity and transverse momentum in the forward hemisphere of the reaction. Radius and correlation strength parameters were obtained from fits of a Gaussian parametrization. The results show a decrease of the radius parameters with increasing transverse momentum characteristic of strong radial flow in the pion source. No striking dependence on pion-pair rapidity or beam energy is observed. Static and dynamic properties of the pion source are obtained from simultaneous fits with a blast-wave model to radius parameters and midrapidity transverse momentum spectra. Predictions of hydrodynamic and microscopic models of Pb+Pb collisions are discussed.Comment: 22 pages, 23 figure

High p_T Spectra of Identified Particles Produced in Pb+Pb Collisions at 158GeV/nucleon Beam Energy

Transverse momentum spectra of pi^{+/-}, p, pbar, K^{+/-}, K^0_s and Lambda at midrapidity were measured at high p_T in Pb+Pb collisions at 158GeV/nucleon beam energy by the NA49 experiment. Particle yield ratios (p/pi, K/pi and Lambda/K^0_s) show an enhancement of the baryon/meson ratio for p_T>2GeV/c. The nuclear modification factor R_{CP} is extracted and compared to RHIC measurements and pQCD calculations.Comment: Quark Matter 2005 parallel section proceeding