Variation in dental wear and tooth loss among known‐aged,older ring‐tailed lemurs (Lemur catta): a comparison between wild and captive individuals

Tooth wear is generally an age‐related phenomenon, often assumed to occur at similar rates within populations of primates and other mammals, and has been suggested as a correlate of reduced offspring survival among wild lemurs. Few long‐term wild studies have combined detailed study of primate behavior and ecology with dental analyses. Here, we present data on dental wear and tooth loss in older (>10 years old) wild and captive ring‐tailed lemurs (Lemur catta). Among older ring‐tailed lemurs at the Beza Mahafaly Special Reserve (BMSR), Madagascar (n=6), the percentage of severe dental wear and tooth loss ranges from 6 to 50%. Among these six individuals, the oldest (19 years old) exhibits the second lowest frequency of tooth loss (14%). The majority of captive lemurs at the Indianapolis Zoo (n=7) are older than the oldest BMSR lemur, yet display significantly less overall tooth wear for 19 of 36 tooth positions, with only two individuals exhibiting antemortem tooth loss. Among the captive lemurs, only one lemur (a nearly 29 year old male) has lost more than one tooth. This individual is only missing anterior teeth, in contrast to lemurs at BMSR, where the majority of lost teeth are postcanine teeth associated with processing specific fallback foods. Postcanine teeth also show significantly more overall wear at BMSR than in the captive sample. At BMSR, degree of severe wear and tooth loss varies in same aged, older individuals, likely reflecting differences in microhabitat, and thus the availability and use of different foods. This pattern becomes apparent before “old age,” as seen in individuals as young as 7 years. Among the four “older” female lemurs at BMSR, severe wear and/or tooth loss do not predict offspring survival. Am. J. Primatol. 72:1026–1037, 2010. © 2010 Wiley‐Liss, Inc.     

Severe wear and tooth loss in wild ring-tailed lemurs (Lemur catta): a function of feeding ecology, dental structure, and individual life history

The ring-tailed lemurs at Beza Mahafaly Special Reserve, Madagascar, exhibit a high frequency of severe wear and antemortem tooth loss. As part of a long-term study, we collected dental data on 83 living adult ring-tailed lemurs during 2003 and 2004. Among these individuals, 192 teeth were scored as absent. The most frequently missing tooth position is M1 (24%). As M1 is the first tooth to erupt, its high frequency of absence (primarily a result of wear) is not remarkable. However, the remaining pattern of tooth loss does not correlate with the sequence of eruption. We suggest that this pattern is a function of 1) feeding ecology, as hard, tough tamarind fruit is a key fallback food of ring-tailed lemurs living in gallery forests; 2) food processing, as tamarind fruit is primarily processed in the P3-M1 region of the mouth; and 3) tooth structure, as ring-tailed lemurs possess thin dental enamel. The incongruity between thin enamel and use of a hard, tough fallback food suggests that ring-tailed lemurs living in riverine gallery forests may rely on resources not used in the past. When comparing dental health in the same individuals (n=50) between 2003 and 2004, we found that individual tooth loss can show a rapid increase over the span of one year, increasing by as much as 20%. Despite this rapid loss, individuals are able to survive, sometimes benefiting from unintentional assistance from conspecifics, from which partially processed tamarind fruit is obtained. Although less frequent in this population, these longitudinal data also illustrate that ring-tailed lemurs lose teeth due to damage and disease, similar to other nonhuman primates. The relationship between tooth loss, feeding ecology, dental structure, and individual life history in this population has implications for interpreting behavior based on tooth loss in the hominid fossil record.     

The impact of dental impairment on ring-tailed lemur food processing performance

During mastication, foods are reduced into particles suitable for swallowing and digestion. Smaller particles possess a greater surface area per unit of volume on which digestive enzymes and bacteria may work than relatively larger particles, and are thus more readily digested. As dental morphology facilitates the breakdown of diets with specific mechanical properties, extensive dental wear and/or tooth loss may impede an individual's ability to break down and exploit foods. We present data demonstrating a relationship between dental impairment and particle size in 43 fecal samples from 33 ring-tailed lemurs at the Beza Mahafaly Special Reserve (BMSR), Madagascar. All fecal samples were sifted through three sieves of decreasing size (11.2 mm, 4.75 mm, and 1.0 mm). The resulting fraction in each sieve was then weighed and assessed in relation to individual dental impairment status. With increasing wear, the percentage of each sample within the 1.0 mm sieve decreases, whereas that in the 11.2 mm sieve increases with increasing postcanine wear, although these effects are not present when limited to individuals without tooth loss. Individuals with tooth loss also demonstrate larger proportions of fecal material 1.0-4.75 mm in size. Dental impairment results in larger food particles and potentially less efficient utilization of foods. When fecal material was examined by leaf vs. fruit content, individuals with tooth loss demonstrated reduced proportions of fruit in the 1.0 mm and 11.2 mm sieves. These data suggest individuals with tooth loss consume less fruit than those without loss, potentially reflecting a reduced ability to process tamarind fruit, a key fallback resource at BMSR.     

The impact of fallback foods on wild ring-tailed lemur biology: A comparison of intact and anthropogenically disturbed habitats

Fallback foods are often viewed as central in shaping primate morphology, and influencing adaptive shifts in hominin and other primate evolution. Here we argue that fruit of the tamarind tree (Tamarindus indica) qualifies as a fallback food of ring-tailed lemurs (Lemur catta) at the Beza Mahafaly Special Reserve (BMSR), Madagascar. Contrary to predictions that fallback foods may select for dental and masticatory morphologies adapted to processing these foods, consumption of tamarind fruit by these lemurs leaves a distinct pattern of dental pathology among ring-tailed lemurs at BMSR. Specifically, the physical and mechanical properties of tamarind fruit likely result in a high frequency of severe tooth wear, and subsequent antemortem tooth loss, in this lemur population. This pattern of dental pathology is amplified among lemurs living in disturbed areas at Beza Mahafaly, resulting from a disproportionate emphasis on challenging tamarind fruit, due to few other fruits being available. This is in part caused by a reduction in ground cover and other plants due to livestock grazing. As such, tamarind trees remain one of the few food resources in many areas. Dental pathologies are also associated with the use of a nonendemic leaf resource Argemone mexicana, an important food during the latter part of the dry season when overall food availability is reduced. Such dental pathologies at Beza Mahafaly, resulting from the use or overemphasis of fallback foods for which they are not biologically adapted, indicate that anthropogenic factors must be considered when examining fallback foods. Am J Phys Anthropol 140:671–686, 2009. © 2009 Wiley-Liss, Inc.     

A comparison of salivary pH in sympatric wild lemurs (Lemur catta and Propithecus verreauxi) at Beza Mahafaly Special Reserve, Madagascar

Chemical deterioration of teeth is common among modern humans, and has been suggested for some extinct primates. Dental erosion caused by acidic foods may also obscure microwear signals of mechanical food properties. Ring-tailed lemurs at the Beza Mahafaly Special Reserve (BMSR), Madagascar, display frequent severe tooth wear and subsequent tooth loss. In contrast, sympatric Verreaux's sifaka display far less tooth wear and infrequent tooth loss, despite both species regularly consuming acidic tamarind fruit. We investigated the potential impact of dietary acidity on tooth wear, collecting data on salivary pH from both species, as well as salivary pH from ring-tailed lemurs at Tsimanampesotse National Park, Madagascar. We also collected salivary pH data from ring-tailed lemurs at the Indianapolis Zoo, none of which had eaten for at least 12 hr before data collection. Mean salivary pH for the BMSR ring-tailed lemurs (8.098, n=41, SD=0.550) was significantly more alkaline than Verreaux's sifaka (7.481, n=26, SD=0.458). The mean salivary pH of BMSR (8.098) and Tsimanampesotse (8.080, n=25, SD=0.746) ring-tailed lemurs did not differ significantly. Salivary pH for the Indianapolis Zoo sample (8.125, n=16, SD=0.289) did not differ significantly from either the BMSR or Tsimanampesotse ring-tailed lemurs, but was significantly more alkaline than the BMSR Verreaux's sifaka sample. Regardless of the time between feeding and collection of pH data (from several minutes to nearly 1 hr), salivary pH for each wild lemur was above the "critical" pH of 5.5, below which enamel demineralization occurs. Thus, the high pH of lemur saliva suggests a strong buffering capacity, indicating the impact of acidic foods on dental wear is short-lived, likely having a limited effect. However, tannins in tamarind fruit may increase friction between teeth, thereby increasing attrition and wear in lemurs. These data also suggest that salivary pH varies between lemur species, corresponding to broad dietary categories.     

Biocultural implications of oral pathology in an ancient Central California population

Bioarchaeologists have long noted two unusual trends in the dentitions of prehistoric Native Californian populations: high rates of wear and low prevalence of caries. The Central California site of CA‐CCO‐548 offers a unique opportunity to examine the relationship between oral pathology and extreme dental wear in a large (n = 480), ancient (4,300–3,100 BP), and temporally well‐defined population sample. This study specifically examines three interrelated processes of the oral cavity in this population: dental wear, dental caries, and periodontal disease. The results show high levels of dental wear (average of 6.1, Smith system), low frequencies of carious lesions (2.5%), low frequencies of periodontal disease (17.8%), and high frequencies of periapical abscesses (10.7%). The pathological processes examined here have complicated multifactorial etiologies. However, they all share the common primary etiological agents of facultative pathogenic bacteria proliferation in the oral biofilm. Integration of the current etiological explanations for infections of the oral cavity, information from the ethnographic record pertaining to subsistence and activity patterns in Native Californian populations, and statistical analysis of specific disease and wear patterns leads to a novel explanation for the observed pattern of oral pathology in this population sample. Specifically, the introduction of antibacterial compounds through dietary items and non‐alimentary tooth use is suggested as the most likely explanation for the unusually low prevalence of dental caries and periodontal disease. Am J Phys Anthropol 154:171–188, 2014. © 2014 Wiley Periodicals, Inc.     

Oral health and the postcontact adaptive transition: A contextual reconstruction of diet in Mórrope,Peru

This work explores the effects of European contact on Andean foodways in the Lambayeque Valley Complex, north coast Peru. We test the hypothesis that Spanish colonization negatively impacted indigenous diet. Diachronic relationships of oral health were examined from the dentitions of 203 late‐pre‐Hispanic and 175 colonial‐period Mochica individuals from Mórrope, Lambayeque, to include observations of dental caries, antemortem tooth loss, alveolar inflammation, dental calculus, periodontitis, and dental wear. G‐tests and odds ratio analyses across six age classes indicate a range of statistically significant postcontact increases in dental caries, antemortem tooth loss, and dental calculus prevalence. These findings are associated with ethnohistoric contexts that point to colonial‐era economic reorganization which restricted access to multiple traditional food sources. We infer that oral health changes reflect creative Mochica cultural adjustments to dietary shortfalls through the consumption of a greater proportion of dietary carbohydrates. Simultaneously, independent skeletal indicators of biological stress suggest that these adjustments bore a cost in increased nutritional stress. Oral health appears to have been systematically worse among colonial women. We rule out an underlying biological cause (female fertility variation) and suggest that the establishment of European gender ideologies and divisions of labor possibly exposed colonial Mochica women to a more cariogenic diet. Overall, dietary change in Mórrope appears shaped by local responses to a convergence of colonial Spanish economic agendas, landscape transformation, and social changes during the postcontact transition in northern Peru. These findings also further the understandings of dietary and biocultural histories of the Western Hemisphere. Am J Phys Anthropol 2010. © 2009 Wiley‐Liss, Inc.     

Interpreting food processing through dietary mechanical properties: a Lemur catta case study

Knowledge of dietary mechanical properties can be informative about physical consequences to consumers during ingestion and mastication. In this article, we examine how Tamarindus indica fruits can affect dental morphology in a population of ring-tailed lemurs (Lemur catta) at Beza Mahafaly special reserve in southwestern Madagascar. Ring-tailed lemurs in tamarind dominated gallery forests exhibit extreme wear and tooth loss on their postcanine dentition that has been related to processing T. indica fruits. We measured and compared mechanical properties of individual food parts in the diet of ring-tailed lemurs in different seasons in 1999-2000, 2008, and 2010. Fracture toughness, hardness, and modulus of foods were measured with a portable mechanical tester. The ripe fruits of T. indica are indeed the toughest and hardest foods ingested by the lemurs. In addition, they are among the largest foods consumed, require high numbers of ingestive bites to process, and are the most frequently eaten by volume. During controlled cutting tests of the ripe fruit shell, multiple runaway side cracks form alongside the cut. Similarly, the lemurs repeatedly bite the ripe shell during feeding and thereby introduce multiple cracks that eventually fragment the shell. Studies of enamel microstructure (e.g., Lucas et al.: BioEssays 30 (2008) 374-385; Campbell et al., 2011) advance the idea that the thin enamel of ring-tailed lemur teeth is susceptible to substantial micro-cracking that rapidly erodes the teeth. We conclude that micro-cracking from repeated loads, in combination with the mechanical and physical properties of the fruit, is primarily responsible for the observed dental damage.     

Grooming behaviors of black‐tailed prairie dogs are influenced by flea parasitism,conspecifics, and proximity to refuge

Grooming is a common animal behavior that aids in ectoparasite defense. Ectoparasites can stimulate grooming, and natural selection can also favor endogenous mechanisms that evoke periodic bouts of “programmed” grooming to dislodge or kill ectoparasites before they bite or feed. Moreover, grooming can function as a displacement or communication behavior. We compared the grooming behaviors of adult female black‐tailed prairie dogs (Cynomys ludovicianus) on colonies with or without flea control via pulicide dust. Roughly 91% of the prairie dogs sampled on the non‐dusted colony carried at least one flea, whereas we did not find fleas on two dusted colonies. During focal observations, prairie dogs on the non‐dusted colony groomed at higher frequencies and for longer durations than prairie dogs on the dusted colonies, lending support to the hypothesis that fleas stimulated grooming. However, the reduced amount of time spent grooming on the dusted colonies suggested that approximately 25% of grooming might be attributed to factors other than direct stimulation from ectoparasites. Non‐dusted colony prairie dogs rarely autogroomed when near each other. Dusted colony prairie dogs autogroomed for shorter durations when far from a burrow opening (refuge), suggesting a trade‐off between self‐grooming and antipredator defense. Allogrooming was detected only on the non‐dusted colony and was limited to adult females grooming young pups. Grooming appears to serve an antiparasitic function in C. ludovicianus. Antiparasitic grooming might aid in defense against fleas that transmit the plague bacterium Yersinia pestis. Plague was introduced to North America ca. 1900 and now has a strong influence on most prairie dog populations, suggesting a magnified effect of grooming on prairie dog fitness.     

Oral health status in elders from South Brazil: a population-based study

doi: 10.1111/j.1741‐2358.2011.00617.x Oral health status in elders from South Brazil: a population‐based study Objective: To assess the oral health status of community‐dwelling adults aged 60 years and older from southern Brazil and to determine demographics, socioeconomic, behavioural and dental risk indicators. Materials and methods: This cross‐sectional study used a multistage, probability sampling method to draw a representative sample of the metropolitan area of Porto Alegre, Brazil. A subsample of 217 subjects was included in this analysis. Oral mucosal lesions, dental caries, tooth loss and periodontal status (full‐mouth, six sites per tooth exam) were assessed by calibrated examiners. Results: Prevalence of edentulism was 39.5%, and mean tooth loss was 20.2 (SE = 0.6). Older individuals [Odds Ratio (OR) = 2.2], women (OR = 2.3), white people (OR = 5.9), individuals of lower socioeconomic status (OR = 5.6) and smokers (OR = 3.5) had higher likelihood of being edentulous. Approximately 36% of dentate individuals had caries and/or restoration affecting, in average, 5.0 teeth. Periodontitis affected 79% of subjects, and it was associated with older age (OR = 4.0), men (OR = 3.4) and large amounts of supragingival plaque (OR = 3.0). Conclusion: Poor oral health was observed in this elderly population from South Brazil. Sociodemographic disparities accounted for most of the burden of disease and treatment needs.     

The sentineling—Foraging trade‐off in dominant and subordinate Arabian babblers

Many cooperative breeders forage under predation risks, sentineling is a central activity, and groupmates have to balance between sentineling and foraging. The optimal balance between sentinel activity and foraging may differ among dominant and subordinate individuals, as dominants are more efficient foragers. Two theoretical models pertain to this balance and predict when individuals with different foraging abilities should switch between the two activities on the basis of their energetic state. In one of these models, individuals must attain a critical energetic level by dusk to pass the night, and in the second model fitness is monotonically increasing with the energetic state. We tested these models in the cooperatively breeding Arabian babbler, Turdoides squamiceps. We measured the length of sentinel bouts and the gaps between them both in natural conditions and following experimental feeding. Following feeding ad libitum, subordinates expanded their sentinel bouts significantly more than dominants in comparison with natural conditions. These findings are consistent with the first model, but not with the second. In the experiment, we measured the mass of mealworms consumed by each individual following a sentinel bout relative to its body mass. This ratio was larger for subordinates, indicating that they ended their sentinel bouts at a lower energetic state than dominants. This finding is consistent with the second model, but not with the first. Immediately after eating ad libitum, in 62% of the cases the first behavior performed by the babblers was a new sentinel bout, but in 17% it was a mutual interaction with a groupmate, indicating that social interactions also play a role in the trade‐off vis‐à‐vis sentinel activity.     

鄱阳湖围垦区藕塘越冬白鹤的时间分配与行为节律

2016年12月—2017年3月,采用瞬时扫描法研究了鄱阳湖围垦区藕塘生境中白鹤Grus leucogeranus越冬期的行为,共扫描2560次,23219只次,包括18031只次成鹤和5188只次幼鹤。结果表明,觅食(41.78%)、警戒(25.02%)、修整(15.00%)和休息(10.84%)是白鹤越冬期的主要行为。与自然生境相比,藕塘生境中白鹤主要采取多休息和修整的策略来节省能量支出。成鹤的觅食行为(35.29%)显著低于幼鹤(62.42%)(F_(1,12)=45.977,P0.01),警戒行为(28.66%)则显著高于幼鹤(10.26%)(F_(1,12)=38.975,P0.01)。家庭群成鹤觅食行为(43.96%)极显著高于非家庭群成鹤(27.04%)(F_(1,12)=60.169,P0.01)。家庭群成鹤需要喂食幼鹤,它们花费更多的时间觅食弥补能量的消耗。行为节律上,白鹤各时段觅食行为占总行为的比例均较高,11:00—11:59出现明显高峰,占总行为的48.64%。警戒行为无明显的低谷和高峰。成鹤在各时段的觅食行为比例均明显低于幼鹤,成鹤和幼鹤的觅食曲线变化趋势相似,即觅食比例的升高和降低比较同步。成鹤在各时段的警戒行为和修整行为比例均明显高于幼鹤,成幼鹤的休息行为比例在各时段差别不大,均在14:00—14:59有个明显的高峰。家庭群成鹤的觅食行为比例几乎在各时段均明显高于非家庭群,家庭群成鹤的修整行为和休息行为在大部分时段均低于非家庭群成鹤。因此家庭群成鹤采取多取食,少休息和修整的策略提高自身的适合度,同时保证对后代的抚育。     

Estimating age of immobilized elephants from teeth impressions using dental silicon

High precision condensation dental silicon, Zetalabor^TM, was used to create moulds of the lower jaw molars from 22 immobilized African elephants (Loxodonta africana Blumenback) during radio collaring operations. These moulds were used to determine the elephant's age using Laws and Jachmann's molar aging criteria. The technique proved easy and fast and produced useful imprints in 90% of the cases. We found our age estimates, based on physical appearance, made prior to immobilizations were relatively accurate, with 75% within ±3 years and 95% within ±5 years from the age indicated from molar evaluation. When re‐collaring the same individuals in 2–3 years, new moulds will be made to compare a known time period with the degree of tooth wear. This will provide verification of Laws age estimates from free‐ranging elephants.     

Nonalimentary tooth use in the neolithic population of the Lengyel culture in central Poland (4600-4000 BC)

One hundred and four skeletons of adult individuals representing Neolithic populations of the Brze?? Kujawski group of the Lengyel Culture (Kuyavia, central Poland, 4600–4000 BC) were analyzed with regard to evidence of nonalimentary tooth use, periapical lesions and antemortem tooth loss (AMTL). Instances of nonalimentary behaviors were found in 47.1% of females and 27.5% of males. Females were primarily characterized by occlusal grooves on the incisors and canines, most probably resulting from yarn production or weaving. The most frequent defect in males was severe tooth wear extending from the incisors to first molars, caused by some hard‐to‐identify nonalimentary activities. Occlusal grooves were also found in males, but their morphology indicates processing of some coarser material. The occupational nature of the tooth defects has been confirmed by archaeological data. The only two burials with grave goods indicative of craft specialization at the sites studied contain the remains of individuals with marks of nonalimentary tooth use. Moreover, the sites provide unequivocal evidence of weaving and basketry production in the form of loom weights and imprints of cloth and mats. Periapical lesions have been found in 40.4% of males and 35.6% of females, and AMTL in 32.1% of males and 36.7% of females. Individuals with evidence of nonalimentary tooth wear are characterized both by ahigher incidence of these lesions in general, and by their more frequent location in the anterior part of the alveolar arch. Am J Phys Anthropol, 2011. © 2010 Wiley‐Liss, Inc.     

Genetic population structure of endangered ring‐tailed lemurs (Lemur catta) from nine sites in southern Madagascar

Madagascar's ring‐tailed lemurs (Lemur catta) are experiencing rapid population declines due to ongoing habitat loss and fragmentation, as well as increasing exploitation for bushmeat and the illegal pet trade. Despite being the focus of extensive and ongoing behavioral studies, there is comparatively little known about the genetic population structuring of the species. Here, we present the most comprehensive population genetic analysis of ring‐tailed lemurs to date from across their likely remaining geographic range. We assessed levels of genetic diversity and population genetic structure using multilocus genotypes for 106 adult individuals from nine geographically representative localities. Population structure and F_ST analyses revealed moderate genetic differentiation with localities being geographically partitioned into northern, southern, western and also potentially central clusters. Overall genetic diversity, in terms of allelic richness and observed heterozygosity, was high in the species (AR = 4.74, H_O = 0.811). In fact, it is the highest among all published lemur estimates to date. While these results are encouraging, ring‐tailed lemurs are currently affected by ongoing habitat fragmentation and occur at lower densities in poorer quality habitats. The effects of continued isolation and fragmentation, coupled with climate‐driven environmental instability, will therefore likely impede the long‐term viability of the species.     

Oral health of the Paleoamericans of Lagoa Santa,central Brazil

The peopling, origins, and early prehistory of the Americas are topics of intense debate. However, few studies have used human remains to document and interpret patterns of health and lifestyle of Paleoamericans. This study provides the first investigation to characterize oral health in a series of early Holocene skeletal remains from Lagoa Santa, Brazil, a locality containing the remains of some of the earliest inhabitants of South America (10,000–7,000 BP). The sample is composed of 949 teeth and 1925 alveoli from an estimated 113 individuals excavated from 17 archaeological sites located in the State of Minas Gerais. We compare dental caries and abscess prevalence at Lagoa Santa to a large sample of human skeletons from the Western Hemisphere Project (WHP) database using both individual and tooth/alveolus count methods. In addition, antemortem tooth loss and tooth wear were analyzed in Lagoa Santa by sex and age. The results show that Lagoa Santa dental caries and abscess prevalence are significantly higher than observed among other hunter–gatherers included in the WHP database, except when abscess prevalence is considered by individual count. Adult females have less tooth wear coupled with higher prevalence of dental caries and antemortem tooth loss than adult males. These results point to an unexpected record of poor oral health at Lagoa Santa, especially among females. A diet based on a highly cariogenic combination of wild tubers and fruits is suggested as an explanation for the elevated rate, characterizing an early adaptation to a tropical environment in South America. Am J Phys Anthropol 154:11–26, 2014. © 2014 Wiley Periodicals, Inc.     

Prey feeding increases water stress in the omnivorous predator Dicyphus hesperus

The effects of water stress (produced by water deprivation and prey feeding) on plant feeding were investigated in the omnivorous predator Dicyphus hesperus Knight (Hemiptera: Miridae). The objective was to determine if prey feeding aggravated water deficits and thus increased plant feeding. We measured plant feeding in a factorial experiment where female D. hesperus were prepared for experiments by providing or withholding water and/or prey for 24 h. We then evaluated the amount of plant feeding on Nicotiana tabacum seedlings by the direct observation of insects at three different densities of the prey, Ephestia kuehniella eggs. The amount of plant feeding, as measured by frequency of plant feeding bouts and time spent plant feeding during observation, was significantly greater for water‐deprived individuals than for those that had been provided with water. Individuals that had been provided with prey fed on plants at a significantly higher frequency than prey‐deprived individuals at two of the prey densities used in the experiment. These results support the hypothesis that plant feeding in zoophytophagous Hemiptera facilitates prey feeding by providing water that is essential for predation.     

Feeding‐related characters in basal pterosaurs: implications for jaw mechanism,dental function and diet

?si, A. 2011: Feeding‐related characters in basal pterosaurs: implications for jaw mechanism, dental function and diet. Lethaia, Vol. 44, pp. 136–152. A comparative study of various feeding‐related features in basal pterosaurs reveals a significant change in feeding strategies during the early evolutionary history of the group. These features are related to the skull architecture (e.g. quadrate morphology and orientation, jaw joint), dentition (e.g. crown morphology, wear patterns), reconstructed adductor musculature and post‐cranium. The most basal pterosaurs (Preondactylus, dimorphodontids and anurognathids) were small‐bodied animals with a wingspan no greater than 1.5 m, a relatively short, lightly constructed skull, straight mandibles with a large gape, sharply pointed teeth and well‐developed external adductors. The absence of extended tooth wear excludes complex oral food processing and indicates that jaw closure was simply orthal. Features of these basal‐most forms indicate a predominantly insectivorous diet. Among stratigraphically older but more derived forms (Eudimorphodon, Carniadactylus, Caviramus) complex, multicuspid teeth allowed the consumption of a wider variety of prey via a more effective form of food processing. This is supported by heavy dental wear in all forms with multicuspid teeth. Typical piscivorous forms occurred no earlier than the Early Jurassic, and are characterized by widely spaced, enlarged procumbent teeth forming a fish grab and an anteriorly inclined quadrate that permitted only a relatively small gape. In addition, the skull became more elongate and body size increased. Besides the dominance of piscivory, dental morphology and the scarcity of tooth wear reflect accidental dental occlusion that could have been caused by the capturing or seasonal consumption of harder food items. □Basal pterosaurs, heterodonty, dental wear, insectivory, piscivory.     

Dental arch shape and tooth wear variability

The rapid rate of tooth wear frequently reported among certain contemporary aboriginal populations has often been attributed to dietary form and abrasives. Several investigators have reported a close correlation between food bulk and the wear planes formed over the dental arches, i.e., steep oblique wear vs. flat horizontal planes. In this investigation we demonstrate that arch shape is an additional and a significant factor influencing the distribution of wear facets and exposed dentin over occlusal surfaces. We examined 64 dental stone casts of Aboriginals from Yuendumu, Central Australia, born between 1900 and 1940. These casts offer a record of the variety of tooth wear and arch forms and their interrelationships. This group of individuals, some subsisting on abrasive and some on soft diets, have dentition which exhibit various wear rates and wear patterns probably due to the diversity of arch shape, size, and occlusal relationships. Hypsiloid or U-shaped maxillas had a more buccally directed wear in contrast to the parabolic or hyperbolic forms, which exhibit a heavier lingual loading. Varying occlusal conditions also contribute to differing wear patterns over the arches. Individuals with alternate intercuspation, for example, have a more horizontally directed wear. These and other conditions of shape, size, and occlusion emphasize the importance of morphological factors in the production of tooth wear rates and patterns in addition to dietary abrasives.