Maxillary canine/third premolar transposition in a prehistoric population from Santa Cruz Island, California.

Canine/premolar transposition is rare in both historic and prehistoric Homo sapiens with a known occurrence of less than 0.10%. This report describes a prehistoric population sample from one site (SCrI-3) on Santa Cruz Island, California in which the rate of C/P3 transposition is greater than eight percent, based on nine of 106 adult crania which exhibit the anomaly either uni- or bilaterally. As a means of investigating the etiology of this anomaly, the location of the canine root in adult crania was studied. Root location should indicate tooth bud origin, a factor likely to be under genetic control. In crania with normally erupted canines, the superior portion of the root averages 4.43 mm from alare, while this distance is 8.96 mm for anomalous roots. This difference suggests that during ontogeny the tooth buds for the canine and premolar arose in the wrong (or reversed) places, causing the teeth to erupt anomalously. It is suggested that inbreeding in a small island community resulted in a short-lived appearance of this anomaly at a high frequency.     

A serologic survey of the island fox (Urocyon littoralis) on the Channel Islands, California.

The island fox is listed as a threatened species in California. A serologic survey of 194 island foxes (Urocyon littoralis) was conducted over the entire range of the species on the Channel Islands (California, USA). Antibody prevalence against canine adenovirus and canine parvovirus reached 97% and 59%, respectively, in some populations sampled. Antibody prevalence of canine herpesvirus, canine coronavirus, leptospirosis and toxoplasmosis were low. Antibodies against canine distemper virus were not detected.     

Maxillary canine-first premolar transposition in two Native American skeletal samples from New Mexico

Tooth transposition is a rare anomaly in which the position of two adjacent teeth in the dental arcade is reversed. Maxillary canine and first premolar transposition (Mx.C.P1 transposition) is most commonly observed. Data from Native Americans samples are lacking. The purpose of this study was: 1) to document the occurrence of Mx.C.P1 transposition, and 2) to generate information on the prevalence of this transposition type among world populations. Eleven cases (M = 5, F = 4, ? = 2) of Mx.C.P1 transposition were identified in skeletal samples from Pecos Pueblo (n = 500) and Sambrito Village (n = 10), both in northern New Mexico. Nine cases were unilateral, 6 affecting the right side and 3 affecting the left side. The remaining 2 cases were bilateral. The prevalence rate of Mx.C.P1 transposition in African and Native American samples, including Pecos Pueblo (1.8%), is higher than in samples from Scotland, Sweden, Saudi Arabia, and India. Mx.C.P1 transposition frequencies vary between geographically distinct populations, although sample composition may be a factor contributing to sample variation. Am J Phys Anthropol 116:45–50, 2001. © 2001 Wiley‐Liss, Inc.     

Porotic hyperostosis in a marine-dependent California Indian population

A maize-based iron- and protein-deficient diet is commonly cited as the most important cause of porotic hyperostosis among American Indian agriculturalists. An alternative to this maize dependence hypothesis is suggested by the analysis of 432 crania from the nonagricultural, fish-dependent population of the Channel Island area of southern California. Cribra orbitalia, a form of porotic hyperostosis associated with iron deficiency anemia, is just as common among these fisherpeople, whose diet was rich in iron and essential amino acids, as it is among maize-dependent agriculturalists. Northern Channel Island crania have much more cribra orbitalia than those from the California mainland. The highest incidence is on San Miguel, a small geographically isolated island with a shortage of fresh water and terrestrial resources. The Indians who lived on Santa Cruz, the largest of the northern Channel Islands with the greatest diversity of terrestrial plants and animals, have less cribra orbitalia than those who lived on Santa Rosa or San Miguel Island. This geographical distribution appears to be explained by island-mainland and interisland differences in water contamination, exposure to fish-borne parasites, and nutritional adequacy of the diet. The prevalence of porotic hyperostosis in a population with a heavy dietary dependence on marine resources shows that among prehistoric American Indians, this condition is not always associated with an iron- and protein-deficient diet of cultigens. It seems likely that high nutrient losses associated with diarrheal disease are often more significant in the etiology of porotic hyperostosis than a low dietary intake of essential nutrients.     

ANALYSIS OF MITOCHONDRIAL DNA POLYMORPHISMS AMONG CHANNEL ISLAND DEER MICE

Mitochondrial DNA (mtDNA) from 131 deer mice, Peromyscus maniculatus, collected on the eight California Channel Islands and from seven southern California mainland locations, was isolated and analyzed for restriction endonuclease fragment polymorphisms. A total of 26 mtDNA genotypes were distinguishable among the deer mice sampled. All of the island samples had mtDNA restriction-fragment patterns not found among the mainland samples. Distributions of specific restriction-fragment patterns provide evidence for at least four separate colonization events to the Channel Islands. The estimated percentage of sequence divergence between all mtDNA's in this study was less than 1%, suggesting that colonization of the islands occurred fairly recently, probably within the last 500,000 years. Levels of mtDNA heterogeneity were much lower within island populations than within mainland populations.     

Aberrant growth of maxillary canine teeth in male babirusa (genus Babyrousa)

A worldwide survey of babirusa skulls curated in museum and private collections located 431 that were from adult males and had retained at least one maxillary canine tooth. Eighty-three of these skulls were identified as exhibiting aberrant maxillary canine tooth growth. Twenty-four of the skulls represented babirusa from Buru and the Sula Islands, and forty-five skulls represented babirusa from Sulawesi and the Togian Islands. The remaining series of fourteen babirusa skulls originally came from zoo animals. Fifteen skulls showed anomalous alveolar and tooth rotation in a median plane. Twenty-nine skulls had maxillary canine teeth that did not grow symmetrically towards the median plane of the cranium. Fourteen skulls showed evidence that the tips of one or both maxillary canine teeth had eroded the nasal bones. Twenty-one skulls had maxillary canine teeth that had eroded the frontal bones. The teeth of two skulls had eroded a parietal bone. One skull had two maxillary canines arising from an adjacent pair of alveoli on the left side of the cranium. Three skulls exhibited alveoli with no formed maxillary canine teeth in them. Analysis suggested that approximately 12% of the adult male babirusa in the wild experience erosion of the cranial bony tissues as a result of maxillary canine tooth growth. There was no skeletal evidence that maxillary canine teeth penetrate the eye.     

Cheek tooth erosion in male babirusa (genus Babyrousa)

The wear on the occlusal surfaces of male babirusa cheek teeth was evaluated in 53 skulls of Babyrousa babyrussa from Buru and the Sula Islands and 87 skulls of B. celebensis from Sulawesi, Indonesia. Based on the comparative lengths of their continually growing maxillary canine teeth, the skulls were divided into five ‘age categories’ (A–E). Numerical and symbolic codes representing tooth wear were applied to each pillar (cusp region) of the mandibular and maxillary permanent third and fourth premolar teeth, and the first, second and third permanent molar teeth. There was no significant difference between the tooth wear patters of skulls in groups A and B, or in groups C and D, and so these were amalgamated. There was close correspondence in wear patterns between each side of the mouth in both species and in each age group. The wear patterns of the mandibular and maxillary teeth, although not identical, were very similar, as were the wear patterns of both species. In group A + B for both species tooth wear was relatively slight, with the M1 teeth experiencing most relative wear. There was almost no wear of the M3 teeth. In group C + D substantial wear of upper and lower M1 was evident. In group E more widespread wear of the cheek teeth was seen, with increased severity of M1 tooth wear, yet there was comparatively much less M2 and M3 tooth wear. The pattern of cheek tooth wear of the Babyrousa spp. was different from that shown by Sus scrofa. Differences in diet selection and processing were highlighted as potential contributing factors. The pattern of cheek tooth wear in male babirusa was not adequate for use to monitor their age.     

Prevalence and patterning of maxillary premolar accessory ridges (MxPARs) in several human populations

We present new data on the prevalence and patterning of the maxillary premolar accessory ridge (MxPAR), a common but understudied morphological dental trait that is expressed as a linear elevation extending from the buccal cusp ridge to the medial sulcus of maxillary premolar teeth. A total of 579 sets of dental casts, representing six ethnic groups, were scored using the five‐grade system proposed by Burnett et al. (2010). The frequency and distribution of the MxPAR were determined by tooth type, sex, side, locus and ethnicity, and the applicability of the scoring system was assessed. The MxPAR was found in approximately two‐thirds of premolar teeth, more often on second than first premolars, and more often on the distal aspect of the occlusal surface than the mesial. There was some evidence that more pronounced forms of the feature occurred more often in males than females, and that there may be some directionality in its expression between sides. Variation was also noted in the frequency of occurrence and degree of expression of the MxPAR between ethnic groups. Intra‐ and inter‐observer concordance rates for scoring the MxPAR were low, confirming that it was difficult to score the trait identically on two different occasions. Our findings have clarified the distribution of the MxPAR within the dentition and between ethnic groups, and highlighted the need for researchers to carry out thorough replicability studies and to decide on an appropriate breakpoint for determining presence or absence of this feature before embarking on genetic studies or bio‐distance analyses. Am J Phys Anthropol 152:19–30, 2013. © 2013 Wiley Periodicals, Inc.     

A tooth wear scoring scheme for age estimation of the Eurasian lynx (<Emphasis Type="Italic">Lynx lynx</Emphasis>) under field conditions

Within the framework of conservation actions for the Eurasian lynx (Lynx lynx), ageing of individuals is required to assess suitability for translocation and to investigate population dynamics and disease epidemiology. We aimed to develop a standardised ageing tool for free-ranging Eurasian lynx, which would be non-invasive, time- and cost-effective, and applicable under field conditions. We used tooth pictures of 140 free-ranging lynx of known age from Switzerland. Tooth colour, calculus, number of incisor teeth and canine, premolar and molar tooth wear were recorded according to pre-defined criteria. Statistical comparisons among the categories of each criterion revealed significant differences for all criteria. Tooth colour and canine tooth morphology showed obvious and consistent alterations with age. Together with the molar tooth shape, premolar tooth tips, incisor teeth and amount of calculus, they pictured the age-related changes in lynx dentition. Crown fractures, enamel flaking and open pulp cavities were observed with an increasing prevalence over age but were also sporadically seen in juveniles. Based on the obtained results, we developed a classification scheme distinguishing six age classes: <?1 year, 1–2 years, 3–6 years, 7–9 years, 10–13 years, ≥?14 years. The scheme was subsequently tested with the same lynx. Classification success rates of different readers ranged from 69 to 88% but errors did not exceed one age class. The homogenous tooth replacement pattern observed in lynx <?1 year allowed us to develop a separate ageing chart to age juveniles in months. The proposed scheme is a promising tool to objectively assign lynx to meaningful age categories.     

新疆罗布泊小河墓地居民的口腔健康与饮食

小河墓地是新疆罗布泊地区一处重要的早期青铜时代墓地。本文主要对该墓地出土颅骨所附牙齿的磨耗程度及牙结石沉积状况进行了观察、量化统计和分析,同时也对该人群其他的口腔疾病如根尖脓肿、颞下颌关节病变、生前牙齿脱落等做了简单的统计,以期从古病理学的角度获取当时居民的口腔健康、食物类型和饮食习惯等信息。本研究发现:1)小河人群的牙齿磨耗程度远远高于对比组的古代居民,其上腭圆枕及颞下颌关节炎出现率较高,存在牙齿崩裂现象,且其前后部牙齿磨耗差异不大。这一方面说明其食物加工技术比较落后,食物粗糙坚硬;另一方面小河居民的经济生活方式和食物构成都比较复杂,不同的食物对前部和后部牙齿磨耗的程度造成了不同的影响;此外,小河人群风沙肆虐的生活环境也对其严重牙齿磨耗的形成产生了一定影响。2)小河人群异常严重的牙结石沉积归功于其高蛋白质和碳水化合物的饮食,以及生活用水的水质。3)统计分析发现两性存在上、下颌犬齿的磨耗差异,而这一情况可能暗示了在家庭手工业方面存在男女分工的现象。     

Cranial injuries as evidence of violence in prehistoric southern California

Crania from the Channel Island area of southern California were examined for evidence of traumatic injuries. Well-healed depressed fractures in the outer table of the cranial vault are common in skeletal remains from the northern Channel Islands (18.56% n = 598) but rare in those from the mainland coast (7.5% n = 146). This prevalence of traumatic injuries among the islanders may be a result of intense competition over resources in a geographically circumscribed environment. The frequency of cranial injuries increases significantly between the early and late prehistoric periods on the Channel Islands. This temporal variation appears to reflect changes in patterns of violence associated with population growth and environmental instability.     

The population genetics of nonmigratory Allen’s Hummingbird (Selasphorus sasin sedentarius) following a recent mainland colonization

Allen''s Hummingbird comprises two subspecies, one migratory (Selasphorus sasin sasin) and one nonmigratory (S. s. sedentarius). The nonmigratory subspecies, previously endemic to the California Channel Islands, apparently colonized the California mainland on the Palos Verdes Peninsula some time before 1970 and now breeds throughout coastal southern California. We sequenced and compared populations of mainland nonmigratory Allen''s Hummingbird to Channel Island populations from Santa Catalina, San Clemente, and Santa Cruz Island. We found no evidence of founder effects on the mainland population. Values of nucleotide diversity on the mainland were higher than on the Channel Islands. There were low levels of divergence between the Channel Islands and the mainland, and Santa Cruz Island was the most genetically distinct. Ecological niche models showed that rainfall and temperature variables on the Channel Islands are similar in the Los Angeles basin and predicted continued expansion of nonmigratory Allen''s Hummingbird north along the coast and inland. We also reviewed previous genetic studies of vertebrate species found on the Channel Islands and mainland and showed that broad conclusions regarding island–mainland patterns remain elusive. Challenges include the idiosyncratic nature of colonization itself as well as the lack of a comprehensive approach that incorporates similar markers and sampling strategies across taxa, which, within the context of a comparative study of island–mainland relationships, may lead to inconsistent results.     

A MORPHOLOGIC AND GENETIC STUDY OF THE ISLAND FOX,UROCYON LITTORALIS

The Island Fox, Urocyon littoralis, is a dwarf form found on six of the Channel Islands located 30–98 km off the coast of southern California. The island populations differ in two variables that affect genetic variation: effective population size and duration of isolation. We estimate that the effective population size of foxes on the islands varies from approximately 150 to 1,000 individuals. Archeological and geological evidence suggests that foxes likely arrived on the three northern islands minimally 10,400–16,000 years ago and dispersed to the three southern islands 2,200–4,300 years ago. We use morphometrics, allozyme electrophoresis, mitochondrial DNA (mtDNA) restriction-site analysis, and analysis of hypervariable minisatellite DNA to measure variability within and distances among island fox populations. The amount of within-population variation is lowest for the smallest island populations and highest for the mainland population. However, the larger populations are sometimes less variable, with respect to some genetic measures, than expected. No distinct trends of variability with founding time are observed. Genetic distances among the island populations, as estimated by the four techniques, are not well correlated. The apparent lack of correspondence among techniques may reflect the effects of mutation rate and colonization history on the values of each genetic measure.     

Black abalone (Haliotis cracherodii) population structure shifts through deep time: Management implications for southern California's northern Channel Islands

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Frequency and distribution of enamel hypoplasias in a historic skeletal sample

A skeletal sample of 296 individuals from a 19th century American poorhouse cemetery is examined for the frequency and chronological distribution of linear enamel hypoplasias on the mandibular canines and maxillary central incisors. Dental enamel hypoplasias may be considered to be indicators of increased exposure to health risk at the time of weaning. The purpose of this study is to examine childhood stress and provide a relative measure of that stress, as evidenced by hypoplasias, in a historic sample that represents an industrializing population. The frequency of enamel hypoplasias per individual by tooth ranged from 70 to 73%, with a peak age at stress of 2.5 to 3 years for the maxillary central incisor and 3.5 to 4 years for the mandibular canine. There were no significant differences in the presence of hypoplasias between males and females. The peak age at stress between 2.5 and 4 years in this 19th century sample transects the ranges reported for prehistoric populations (2-6 years) and for modern groups (0-3 years). These results indicate that the stress associated with weaning probably occurred earlier in incipient industrial societies than in prehistoric hunter/gatherers and agriculturalists, yet not as early as in modern industrial groups. The high level of childhood stress in this skeletal sample compared with that of other samples may indicate a change in health, at least among the lowest class, associated with the cultural transition from an agricultural to an industrial society.     

New evidence on the spatiotemporal distribution and evolution of the Uto-Aztecan premolar

Uto-Aztecan premolar (UAP) is a rare morphological feature of the maxillary first premolar that occurs in Native American populations with frequencies ranging 0-16.7%. A recent summary of UAP by Delgado-Burbano et al. (2010) suggests the trait evolved around 4,000 BP in the American Southwest where the earliest cases occur and where the trait exists at the highest frequencies among contemporary populations. In this article, we present new data on UAP prevalence from an Archaic North American sample from Buckeye Knoll, Texas (circa 7,500-6,200 cal BP). Buckeye Knoll preserves a single case of UAP, and a sample frequency of 3.6%. In addition, we confirm the presence of UAP in other eastern North American Archaic skeletal samples from the Windover and Harris Creek at Tick Island sites in Florida. We also review the dental morphological literature to assess: 1) whether UAP prevalence is limited to New World populations, and 2) whether the trait's antiquity can be extended further into the Early Holocene Paleoindian period. Additional cases of UAP are presented from the Pacific coast of South America, Europe, Asia, and Australia. Combined, these data greatly expand the spatial and temporal distribution of UAP and suggest the trait evolved considerably earlier than previously thought.     

Precise chronology of differentiation of developing human primary dentition

While correlation of developmental stage with embryonic age of the human primary dentition has been well documented, the available information regarding the differentiation timing of the primary teeth was largely based on the observation of initial mineralization and varies significantly. In this study, we aimed to document precise differentiation timing of the developing human primary dentition. We systematically examined the expression of odontogenic differentiation markers along with the formation of mineralized tissue in each developing maxillary and mandibular teeth from human embryos with well-defined embryonic age. We show that, despite that all primary teeth initiate development at the same time, odontogenic differentiation begins in the maxillary incisors at the 15th week and in the mandibular incisors at the 16th week of gestation, followed by the canine, the first primary premolar, and the second primary premolar at a week interval sequentially. Despite that the mandibular primary incisors erupt earlier than the maxillary incisors, this distal to proximal sequential differentiation of the human primary dentition coincides in general with the sequence of tooth eruption. Our results provide an accurate chronology of odontogenic differentiation of the developing human primary dentition, which could be used as reference for future studies of human tooth development.     

Static intraspecific allometry of jaws and teeth in Cercopithecus aethiops

Adult static intraspecific allometry of jaw size and tooth area was evaluated in a sample of 100 Cercopithecus aethiops crania (50 male, 50 female). Tooth areas were calculated from mesiodistal and buccolingual measurements of all the teeth in both arcades and were scaled to four viscero-cranial measurements: bimaxillary breadth, maxillo-alveolar length, mandibular length and bigonial width. Allometric coefficients calculated for jaw dimensions alone indicate tighter viscerocranial integration in females than in males. A finding of note was that half of the variation in maxillo-alveolar length may be accounted for by variation in mandibular length: females are isometric, males negatively allometric.
A similar degree of allometric mosaicism was found when maxillary incisor size was scaled to maxillary length and width. In females, the relationship was negatively allometric, whilst incisor size in males was found to be unrelated to either. Negative allometry characterized the relationship of canine base area to jaw length in both sexes, with males additionally being positively allometric to mandibular width.
The scaling of postcanine tooth areas to jaw length was characterized by a dichotomous pattern: males showed significant mandibular integration whilst females showed only significant maxillary integration. Compensatory tooth size interaction between maxillary canine base area and the summed incisor and postcanine areas was suggested by the significant negative allometric relation between them.     

Prevalence and characterization of Salmonella spp. among marine animals in the Channel Islands, California

Salmonella enterica is a zoonotic pathogen that has been isolated from free-ranging marine mammals throughout the world, with animals in the Channel Islands of California (USA) showing the highest prevalence. The goal of this study was to determine prevalence, antimicrobial sensitivity and genetic similarity using pulsed-field gel electrophoresis (PFGE) of Salmonella in several non-domestic animal species on San Miguel and San Nicolas Islands. Fecal samples were collected from 90 California sea lion Zalophus californianus pups, 30 northern elephant seal Mirounga angustirostris pups and 87 western gulls Larus occidentalis in the Channel Islands and 59 adult male sea lions in Puget Sound, WA (USA). Salmonella were isolated, identified and serotyped, followed by antimicrobial susceptibility testing and PFGE. Of the California sea lion pups that were sampled on the islands, 21% (n = 19) were positive for Salmonella, whereas no adults males in Puget Sound were positive. Of the northern elephant seal pups sampled, 87% (n = 26) were harboring Salmonella. Only 9% (n = 8) of western gulls were shedding Salmonella, with one of these gulls harboring the only antimicrobial resistant isolate. The serotypes found in these animals were Enteritidis, Montevideo, Newport, Reading, and Saint Paul. The only serotype that showed variation on PFGE was Newport. The pinnipeds of the Channel Islands harbor Salmonella at a higher prevalence than pinnipeds from other geographic areas observed in previous studies. Researchers and veterinarians should exercise increased caution when working with these animals due to the zoonotic potential of Salmonella.     

Brief communication: physiological stress in the Florida Archaic-enamel hypoplasia and patterns of developmental insult in early North American hunter-gatherers

We examined the prevalence and developmental timing of linear enamel hypoplasias (LEHs) in an early Archaic Floridian population from Windover (8,120-6,980 (14)C years B.P. uncorrected). Using digital images, mandibular and maxillary canines were analyzed for defect prevalence and timing of insults. Although overall prevalence was very weakly correlated with earlier defect timing, there were significant differences in defect prevalence that varied by sex and tooth type. The mean LEH count in male mandibular canines was far higher than in male maxillary canines or in female mandibular or maxillary canines. We examined defect timing as a possible predictor of the sex differences in LEH prevalence. There were no significant sex differences in the developmental timing of the earliest defects in either tooth class. Developmental timing is not responsible for the sex differences seen in defect prevalence in mandibular canines.