Crown dimensions of deciduous teeth from prehistoric India

Mean mesiodistal and buccolingual diameters are presented for deciduous teeth from the important Chalcolithic site of Inamgaon (1400–700 B.C.), a prehistoric farming community on the Deccan Plateau of western India. The deciduous teeth from Inamgaon are consistently larger than deciduous teeth of modern populations of European descent and smaller than the deciduous teeth of modern Australian aboriginals. Comparative data for prehistoric deciduous teeth are rare, especially for populations of southern Asia. The deciduous teeth of Mesolithic Europeans are comparable in size to certain dimensions of the Inamgaon teeth, and a small sample of deciduous teeth from the Iron Age site of Pomparippu (Sri Lanka) exhibits larger anterior teeth and smaller molar teeth than does the sample from Inamgaon.     

Crown dimensions of deciduous teeth from pre-Columbian Peru

The mean mesiodistal and buccolingual diameters are presented for the deciduous teeth from Pre-Columbian Peru. Generally, the deciduous teeth from Pre-Columbian Peru are larger in most dimensions than the deciduous teeth of modern populations of European descent and smaller than those of modern Australian aboriginals. Differences in crown dimensions between the Pre-Columbian Peruvian deciduous teeth and those from Prehistoric Inamgaon and Mesolithic Europe are inconsistent. However, the maxillary and mandibular second molars are larger in the Peruvian population while the incisors are smaller. Since comparative data for prehistoric deciduous teeth are rare, this paper adds valuable data to the growing literature on deciduous crown dimensions.     

Coronal breadth of human primary anterior teeth

Original data for mesiodistal diameter of deciduous anterior teeth on 180 White children show: (1) mean size is smallest for the lower central incisor and largest for the upper canine, (2) means from combining widths on the left anterior teeth of each arch are larger in the maxilla than the mandible by 4.0 mm, (3) individual differences for widths of the upper central and lateral incisors extend from one child with these teeth of similar size to another child with the central incisor larger than the lateral by 2.3 mm, and (4) anterior tooth correlations are positive, varying from r = 0.4 for upper canine width with width of lower central incisor, to r = 0.8 for combined widths of left anterior teeth in the maxilla with combined widths of their antagonists. Comparative findings are drawn from investigations on Australian aborigines, South African Bushmen, Liberian Negroes, Tristan da Cunha islanders, Japanese, Japanese-Negro admixtures, Japanese-White admixtures, White groups living in several parts of Europe, and North American Whites. Among these ethnic groups, Australian aborigines have the largest deciduous anterior teeth. Composite means on each sex for North American Whites show boys to have slightly larger anterior deciduous teeth than girls.     

Trophi Structure in Bdelloid Rotifers

Bdelloids show a rather uniform morphology of jaws (trophi), named ramate. The most recognizable feature is the presence of a series of teeth forming unci plates. The unci are not uniform in size; each plate has 1–10 major median teeth. Using SEM pictures of trophi and data from the literature, we analyzed the number of major unci teeth in relation to trophi size, total number of teeth, and environmental features. Variability in the number of major unci teeth in bdelloids is not related to trophi size or to total number of unci teeth, while total number of unci teeth and trophi size seem to be related to each other: larger trophi in general have more teeth than smaller trophi. Few major teeth are more common in species living in water bodies where they possibly eat unicellular algae, while more major teeth are more common in species living outside water bodies, among mosses and lichens, where they possibly eat bacteria.     

The diet and dentition of Smooth newt larvae (Triturus vulgaris)

This paper describes the dentition and diet of a population of Smooth newt larvae. The development of the teeth and their increase in number with age are discussed. The number of teeth on all five tooth-bearing bones appear to be controlled by a single developmental system. Young larvae eat chydorids, daphniids and cyclopoid copepods; after they reach a total length of about 15 mm, chironomid larvae comprise the greater part of the diet. In the study population, ostracods were not eaten, and cannibalism was not observed. There was no tendency for larger larvae to select larger individuals of a given species of prey.
It is suggested that the exponential rate of growth in weight forces larvae of more than about 15 mm total length to switch from passive to active hunting. This enables them to catch larger prey, at the expense of incurring a higher rate of mortality. This increase in mortality is associated with a reduction in the variation of morphological characters, including dentition, which is thought to be caused by natural selection. The function of different components of the dentition are discussed. It was found that larvae of a given age which have more teeth than average have in their guts fewer prey than average, and an explanation is suggested.     

Folivory, frugivory, and postcanine size in the cercopithecoidea revisited

At a given body mass, folivorous colobines have smaller postcanine teeth than frugivorous cercopithecines. This distinction is a notable exception to the general tendency for folivorous primates to have relatively larger postcanine tooth rows than closely related frugivores. The reason for this anomalous pattern is unclear, but one potential explanation is that the difference in facial size between these two subfamilies confounds the comparison-i.e., it may be that the large postcanine teeth of cercopithecines are a consequence of their large faces. The goal of this study was to test this hypothesis. Phylogenetic comparative methods were used to examine the relationships among postcanine area, facial size, and body mass in 29 anthropoid primates, including eight colobines and eight cercopithecines. Results indicate that there is a strong and highly significant partial correlation between postcanine area and facial size when body mass is held constant, which supports the hypothesis that facial size has an important influence on postcanine size. Moreover, colobines have larger postcanine teeth relative to facial size than cercopithecines. Surprisingly, when facial size is held constant, the partial correlation between postcanine area and body mass is weak and nonsignificant. These results suggest that facial size may be more appropriate than body mass for size-adjusting postcanine measurements in some contexts. A phylogenetic comparative test of the association between diet and relative postcanine size (scaled using facial size) confirms that folivorous anthropoids are characterized by relatively large postcanine teeth in comparison to closely related nonfolivores.     

Juvenile and adult teeth of the titanosaurian dinosaur Lirainosaurus (Sauropoda) from the Late Cretaceous of Iberia

A large sample of more than 100 teeth of the titanosaurian sauropod Lirainosaurus astibiae from the Late Cretaceous Laño quarry (Northern Spain) has been studied. Most of the teeth are small (crown height less than 13 mm), cylindrical, with parallel edges and smooth enamel; a few larger teeth are tapered and have more ornamented enamel. These differences are regarded here as ontogenetic changes, the small teeth being interpreted as those of juveniles and the large ones as those of subadult or adult individuals. The juvenile teeth also present some differences in the apex of the crown: some of them have a tapered tip, and others have apical and/or mesial/distal facets. The first are probably unerupted or non-functional teeth, while the ones with wear facets are functional teeth. This is the first time a change in the microwear structures of the apical wear facets between juvenile and adult teeth is observed in a titanosaurian taxon. Moreover, this let us to hypothesize a switch in the diet and food processing between the juvenile and adult individuals of Lirainosaurus. Finally, the teeth of Lirainosaurus are different from those of the Late Cretaceous European titanosaurs described to date and also differ from the teeth of basal titanosauriforms from the Early Cretaceous of the Iberian Peninsula.     

新疆准噶尔盆地北缘中中新世阿特拉旱松鼠及其生态环境讨论

记述了新疆准噶尔盆地北缘中中新世哈拉玛盖组的两种阿特拉旱松鼠化石:Atlantoxerus junggarensis和A.xiyuensis sp.nov.。依据新的化石材料将A.junggarensis特征进行了修订。新种A.xiyuensis颊齿较小,齿冠低;P4大于或等于M1/2,次尖明显,原小尖发育,后小尖强大、明显大于后尖且一般不与后边脊相连,通常无中附尖;M1/2原小尖弱;m3无下前边尖和前齿带,无下中尖、下中附尖和下次小尖,下后脊粗壮、由下原尖伸向跟凹、不与下后尖相连,下内尖及下内脊发育。Atlantoxerus属最早的化石记录出现在中亚地区,推测它很可能起源于中亚,然后向西亚、欧洲和北非地区扩散。依据伴生动物群和相关古植物的研究成果推测,Atlantoxerus属可能生活在温暖湿润的环境中。随着晚新生代全球气温变冷,该属的分布渐趋收缩,分异度减小,表明了其地理分布与温度变化密切相关。同时推测,温度对其生存的影响似乎比湿度更大。     

Dentition in the African catfishes Andersonia (Amphiliidae) and Siluranodon (Schilbeidae) previously considered toothless

Based on light and scanning electron microscopic examination of their morphology, the dentition on both the premaxilla and dentary of Andersonia (Amphiliidae) and Siluranodon (Schilbeidae) catfishes is described from samples taken from tributaries of the White Nile in south‐western Ethiopia. These monotypic African genera were previously believed to lack teeth on the lower jaw in Andersonia and on both jaws in Siluranodon . Siluranodon exhibits an ontogenetic reduction: teeth were less frequently found in larger individuals than in smaller ones. In contrast to the adults of all other schilbeids, whose oral teeth are arranged in multiserial (or at least, biserial) bands, Siluranodon has uniserial teeth on both the premaxilla and the dentary. The adaptive, ontogenetic and phylogenetic aspects of jaw‐tooth reduction in catfishes are discussed.     

河南浙川的人类牙齿化石

<正> 1973年夏我所邱占祥同志等在河南南阳市的中药材仓库中发现一枚人的上前臼齿。据仓库同志说,它是从淅川县收购来的。本文作者与孙文书同志于同年9月前往南阳地区,与南阳市博物馆王儒林同志等一起从南阳药材仓库和西峡县药材仓库及药店的“龙骨”中又找到十二枚人的牙齿化石。据了解,这些化石都是在淅川县收购以后转运来销售     

Biocultural analysis of sex differences in mortality profiles and stress levels in the late medieval population from Nova Raca, Croatia

Human skeletal remains of 104 individuals from the late medieval (14th-18th century) Nova Raca cemetery, in continental Croatia, are described. Historic data from the parish Book of the Dead, relevant to a period in the early 19th century, suggest that females may have been under greater stress than males. To test this hypothesis, the skeletal material is analyzed for the presence and distribution of enamel hypoplasias and cribra orbitalia. Observations are also made on the presence and pattern of dental disease, skeletal infection, trauma, osteoarthritis, vertebral degenerative changes, and Schmorl's depression frequencies. The mortuary sample, consisting of 36 subadults and 68 adults, exhibits underrepresentation of subadults, and differential adult male/female mortality profiles. Peak female mortality is between 21-25 years, compared to peak male mortality between 31-35 years. Average adult female age at death is 29.9 years, compared to 34.1 years in adult males. Significant sex differences are present in the frequencies of enamel hypoplasia. Adult females have higher frequencies of hypoplastic teeth, and a larger number of defects in the teeth affected than in males. Subadults in the series also exhibit higher frequencies of hypoplastic teeth, and a larger number of defects in the teeth affected than in adults, documenting a relationship between enamel hypoplasia-causing stress events and reduced life expectancy. Significant sex differences are also present in dental pathology frequencies, possibly reflecting differences in resource access. Sex differences in vertebral osteoarthritis and Schmorl's depression frequencies may reflect differential activity patterns.     

步氏巨猿牙齿大小上的变异性和南方古猿类食性假说

步氏巨猿牙齿大小上的变异性表明,在柳城巨猿洞局部地区的堆积中可能有少量时代稍晚的巨猿牙齿标本。晚期步氏巨猿与早期的相比,后部齿显著增大而前部齿则无显著差异。从步氏巨猿牙齿在大小上的演化趋势来看,南非南方古猿类中的纤细类与粗壮类之间在齿列比例上的不同不一定意味着其食性上有大的差异,纤细类与粗壮类也未必有“属”这一分类级别上的差异。     

Permanent tooth sizes in 46,XY females.

The teeth of seven Finnish patients with complete testicular-feminization syndrome (46,XY females) were studied to obtain further information about their growth and possible somatic determinants on the Y chromosome. The sizes of the permanent teeth of the 46,XY females were found to be as large as those of control males and definitely larger than those of control females. Testicular feminization is caused by androgen insensitivity, and persons affected are phenotypically females. Hence, these results also indicate the influence of the Y chromosome on dental determination.     

Metrical dental analysis on golden monkey (Rhinopithecus roxellana)

Dental variation in the Chinese golden monkey (Rhinopithecus roxellana) is here evaluated by univariate, bivariate, and multivariate analyses. Allometric analyses indicate that canines and P3s are positively, but other dimensions negatively scaled to mandible and maxilla, and to body size. With the exception of the mesiodistal dimensions of I₁ and M₃, and the buccolingual dimension of P₄, mandibular dental variables show similar scaling relative to body size. Analysis of residuals shows that males have significantly larger canine, P³ and buccolingual dimensions of the postcanine teeth (M² and M³) than females. A significant difference in shape between the sexes is found in the buccolingual dimension of the upper teeth, but not in the mandible. Unlike the situation in some other species, female golden monkeys do not exhibit relatively larger postcanine teeth than males. In fact, the reverse is true, expecially for M²s and M³s. The fact that most of the dental variables show low negative allometry to body size might be related a cold environment that has led to the development of larger body size with reduced energy loss. When the raw data are examined by Discriminant Function Analysis the sexes are clearly distinguishable.     

Analysis of samples of Hipparion(Mammalia,Perissodactyla) from the Concud localities,Turolian of Spain

Samples, mainly of isolated teeth, of Hipparion concudensePirlot from the Turolian fossil sites “Concud”. Cerro de la Garita, Barranco de las Calaveras, Concud III, Masia del Barbo, and Los Mansuetos, all in the Calatayud-Teruel area, Spain, are analysed and compared. The teeth from “Concud”, Cerro, and Masia are similar and larger than those from Barranco, Concud III, and Los Mansuetos, which between them are similar. A possible trend towards decrease in size is indicated. The stratigraphic position of these sites is briefly discussed.     

Postcanine tooth size in female primates

The results of many allometric studies of postcanine tooth size in mammals have not corresponded to expectations of tooth size based on energy requirements and dental function. The purpose of this study is to investigate the relationship between postcanine occlusal surface area, body size, and the metabolic demands of pregnancy and lactation in female primates. Tooth and body sizes from 38 primate species were taken from the literature to test two hypotheses: 1) females should have relatively larger teeth than males in order to masticate additional food for the energetic costs of reproduction; 2) taxa with the largest neonatal size (a measure of average metabolic costs of pregnancy and lactation) should have females with a greater degree of relative dental enlargement. The results show that relatively large female teeth are not found consistently in primate species. Females have less occlusal surface area than expected on the basis of the male tooth and body size regression in 21% of the species, and there is no correlation between relative female tooth size and relative newborn size across higher primate taxa. The degree of female dental enlargement is most closely related to degree of sexual dimorphism in body weight. The correlation between degree of body weight dimorphism and relatively larger postcanine teeth in females than in males is 0.87 in the 38 species. Species that are monomorphic in weight tend to be monomorphic in tooth size even though females apparently require more food than males.(ABSTRACT TRUNCATED AT 250 WORDS)     

Ramapithecus and Sivapithecus from China: Some implications for higher primate evolution

The pattern of overall dental dimensions in over 900 teeth of ramapithecines from Lufeng in China is examined using frequency distribution histograms and fitted normal curves, and compared with data for extant hominoids. A prior study has demonstrated unequivocally that at least two groups of animals must have existed at Lufeng [Wu and Oxnard, 1983; Oxnard, 1983a]. The present investigation confirms this finding in more detail. In addition it shows that one fossil group possesses smaller teeth with a lesser degree of sexual dimorphism and approximately equal numbers of adult males and females, and the other possesses larger teeth with a rather larger degree of sexual dimorphism and a female-male ratio that may have approximated from as low as 2:1 to as high as 4:1. Comparisons of patterns of difference along the tooth row demonstrate that both these forms differ from modern apes in their sexual dimorphism, the smaller form being more like humans than the larger, which is more like apes, especially orangutans. Comparisons of the areas of the canine teeth with each of the other functional segments of the tooth row again show that the smaller form is basically similar to modern humans and that the larger resembles extant great apes. Comparisons of other functional dental areas seem to relate to dietary and masticatory functions. Thus the cutting areas are large relative to the chewing areas in omnivorous humans, whereas in the essentially vegetarian great apes this ratio is smaller. The smaller fossil resembles the human condition and may have been somewhat omnivorous; the larger one more resembles the apes and may have been somewhat more vegetarian. However, these comparisons also show that the way in which the larger form resembles the apes is associated with special development of the canines, which is different from that in any modern ape. Comparisons show that the canines in the larger form project far beyond the normal line of tooth crowns. Finally, comparisons show that canine sexual dimorphism in height is marked in the larger form. Neither of these last two features is true of the smaller fossil. These findings have implications for our understanding of the evolution of early pongids and hominids, and for the evolution of primate sexual dimorphisms and dental mechanisms.     

Tooth Size Variation in Pinniped Dentitions

It is contentious whether size variation among mammalian teeth is heterogeneous or homogeneous, whether the coefficient of variation is reliable, and whether the standard deviation of log-transformed data and the residual of standard deviation on mean variable size are useful replacements for the coefficient of variation. Most studies of tooth size variation have been on mammals with complex-crowned teeth, with relatively little attention paid to taxa with simple-crowned teeth, such as Pinnipedia. To fill this gap in knowledge and to resolve the existing controversies, we explored the variation of linear size variables (length and width) for all teeth from complete permanent dentitions of four pinniped species, two phocids (Histriophoca fasciata, Phoca largha) and two otariids (Callorhinus ursinus, Eumetopias jubatus). Size variation among these teeth was mostly heterogeneous both along the toothrow and among species. The incisors, canines, and mesial and distal postcanines were often relatively highly variable. The levels of overall dental size variation ranged from relatively low as in land carnivorans (Phoca largha and both otariids) to high (Histriophoca fasciata). Sexual size dimorphism varied among teeth and among species, with teeth being, on average, larger in males than in females. This dimorphism was more pronounced, and the canines were larger and more dimorphic relative to other teeth in the otariids than in the phocids. The coefficient of variation quantified variation reliably in most cases. The standard deviation of log-transformed data was redundant with the coefficient of variation. The residual of standard deviation on mean variable size was inaccurate when size variation was considerably heterogeneous among the compared variables, and was incomparable between species and between sexes. The existing hypotheses invoking developmental fields, occlusal complexity, and the relative timing of tooth formation and sexually dimorphic hormonal activity do not adequately explain the differential size variation along the pinniped toothrow.     

Phylogenetic aspects of tooth and jaw structure of the Medaka, Oryzias latipes, and other beloniform fishes

Tooth structure is described for adult male, female, and juvenile Oryzias latipes (Temminck & Schlegel), the Medaka. Adult males have enlarged, unicuspid teeth posteriorly on the premaxilla and dentary. Oral teeth are smaller and more numerous in females, in which no tooth is notably larger than the others. Juveniles have numerous small teeth from about 3 mm SL (standard length) onwards. By about 16 mm SL, males begin to develop the large posterior teeth, as well as other secondary sexual characters. Lower and upper pharyngeal teeth of both males and females are fine, and in numerous even rows.
The large, posterior oral teeth of males are fully-ankylosed to the attachment bone, and, hence, are not depressible. In female Medaka, as in the Halfbeak Dermogenys pusillus van Hasselt, the oral teeth have a ring of unmineralized collagen at the base, and are not depressible. Pharyngeal teeth of Medaka have a ring of unmineralized collagen at the base, and a distinct wedge of collagen absent posteriorly, such that the pharyngeal teeth may be depressed.
Bone in adult Medaka is acellular. Incompletely mineralized teeth, acellular bone, a protrus-ible upper oral jaw, and a mobile branchial apparatus with an interhyal bone, form a complex characteristic of advanced teleosts. The Medaka differs in several ways from the model advanced teleost: absence of an interhyal bone, ascending and articular processes of the premaxilla, and the rostral cartilage, as well as presence of cartilaginous symphyses between the dentaries and premaxillae, all contribute to the fixed or nonprotrusible jaws.
Reduction in the premaxilla is a derived character within beloniform fishes for which an enlarged, beaked outer jaw is considered plesiomorphic.     

The dentition of the Indian Knoll skeletal population: odontometrics and cusp number.

Data on the permanent dentition of 153 individuals from the well known Indian Knoll skeletal population are presented. Mesiodistal and buccolingual measurements were taken with a Helios dial caliper. Cusp number of maxillary and mandibular molars are recorded. The Indian Knoll dentition is larger than many modern groups but smaller than Australoid or Mesolithic groups. With the exception of maxillary 12, males have larger teeth than females in both dimensions. The lower canine is the most dimorphic tooth. Through rank order correlation, an association was shown between the sexual dimorphism of the mesiodistal and buccolingual dimensions. Compared to modern groups, the Indian Knoll population displays a moderate degree of sexual dimorphism in tooth size. In general, the coefficients of variation were greater for the more distal teeth within morphological classes. Amounts of size variability did not differ significantly between the sexes; moreover, rank order correlations indicated that patterns of variability in both dimensions were similar for males and females. The predominant cusp number pattern for upper molars is 4-3-3 and for lowers 5-5(4)-5. No sex differences were shown for cusp occurrence or bilateral asymmetry in cusp number.