A factor analysis of morphogenetic fields in the human dentition

The traditional morphogenetic fields of the human dentition were evaluated by means of factor analysis of dental dimensions taken from a series of human crania. When crown length, crown width and crown index were considered separately, factors emerged which could be identified with the tooth group fields. But a combined crown length-crown width analysis generated factors which extended beyond the regional tooth groups. Crown width itself was revealed to be an important axis of morphologic intergration. It was concluded that univariate methods are not adequate for identifying morphogenetic fields; the teeth must be treated as multidimensional units where the correlation among dimensions is accounted for.     

Morphologic characteristics of the Alaskan Eskimo dentition. II. Carabelli's cusp

A study of coastal and inland Alaskan Eskimos revealed that a faintly developed Carabelli's cusp was present in 42.7%. No sex difference in the occurrence of Carabelli's cusp was evident and no family showed any difference in the distribution of the frequencies when each family was compared to the rest of the population. A general tendency toward a higher prevalence of Carabelli's cusp in the coastal Eskimos may be due to more admixture with white people along the coast. Alaskan Eskimos have a significantly higher frequency of Carabelli's cusp than do Aleuts. Statistical evaluation revealed that in the Alaskan Eskimo dentition the formation of Carabelli's cusp is independent of the size of the molars and the suppression of the third molars.     

Phenotypic selection on the dentition in a Late Archaic population of Ohio

Significant phenotypic selection acting on the buccolingual diameters of the permanent first and second molars is established for a Late Archaic population in Ohio. Directional selection appears to be acting on an index that increases the size of the maxillary first (UM1) and mandibular second (LM2) molars and decreases the size of the maxillary second (UM2) and mandibular first (LM1) molars. Variance selection is fundamentally disruptive but results in a more integrated (highly correlated) set of characteristics in the after-selection sample.     

Sexual differences in the anterior dentition in African primates

A study was made of ranges of variation of the anterior dentition of various African nonhuman primates. Comparisons of the dentitions were made between different species and sex differences within each species were determined. Among the nonhuman primate groups studied were: Gorilla gorilla gorilla, Pan troglodytes, Pan paniscus, Cercopithecus nictitans, Cercocebus albigena and Colobus badius. In monkeys the canine teeth of the males are considerably larger than those of the females. There are also considerable differences in size in the rest of the anterior dentition. In apes, and specifically only gorillas, distinct sex differences are only found in the maxillary canines. In the chimpanzees, sex differences in the dentition are much smaller and there is considerable overlap in the ranges of variation. There are no fundamental differences in the size of the rest of the anterior dentition in the apes. The present study shows that differences due to sex in the anterior dentition, excluding the canine, are not as great as has been considered. If we consider the fossil record of man, whose morphological complex includes a much reduced canine, the probability will be that sex differences in the rest of the dentition will be negligible. Given the fragmentary nature of the fossil record, it is, therefore, highly unlikely that the determination of the sex of any fossil hominid specimen can be accurately made based solely on the evidence of its dentition.     

Metric variation and sexual dimorphism in the dentition of Ouranopithecus macedoniensis

The fossil sample attributed to the late Miocene hominoid taxon Ouranopithecus macedoniensis is characterized by a high degree of dental metric variation. As a result, some researchers support a multiple-species taxonomy for this sample. Other researchers do not think that the sample variation is too great to be accommodated within one species. This study examines variation and sexual dimorphism in mandibular canine and postcanine dental metrics of an Ouranopithecus sample. Bootstrapping (resampling with replacement) of extant hominoid dental metric data is performed to test the hypothesis that the coefficients of variation (CV) and the indices of sexual dimorphism (ISD) of the fossil sample are not significantly different from those of modern great apes. Variation and sexual dimorphism in Ouranopithecus M(1) dimensions were statistically different from those of all extant ape samples; however, most of the dental metrics of Ouranopithecus were neither more variable nor more sexually dimorphic than those of Gorilla and Pongo. Similarly high levels of mandibular molar variation are known to characterize other fossil hominoid species. The Ouranopithecus specimens are morphologically homogeneous and it is probable that all but one specimen included in this study are from a single population. It is unlikely that the sample includes specimens of two sympatric large-bodied hominoid species. For these reasons, a single-species hypothesis is not rejected for the Ouranopithecus macedoniensis material. Correlations between mandibular first molar tooth size dimorphism and body size dimorphism indicate that O. macedoniensis and other extinct hominoids were more sexually size dimorphic than any living great apes, which suggests that social behaviors and life history profiles of these species may have been different from those of living species.     

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.     

Expression of Dlx genes during the development of the murine dentition

The mammalian Dlx homeobox gene family has been shown to play multiple roles in tooth development, but a detailed comparison of the expression pattern of all members throughout tooth development has been lacking. We provide such an analysis for the six known murine Dlx genes. The expression patterns for these genes allow a refinement of previously proposed models for the role of Dlx genes in tooth type specification and raise the possibility of roles for subsets of these genes in tooth initiation, morphogenesis (enamel navel formation, enamel knot induction, cervical loop growth), and enamel formation. The relationship of Dlx gene expression to their genomic organization suggests coordinate regulation of linked genes at early stages but regulatory differences at later stages. Received: 19 July 1999 / Accepted: 3 December 1999     

Factors affecting the distribution of enamel hypoplasias within the human permanent dentition

Frequencies and morphological and chronological distributions of enamel hypoplasias are presented by tooth type (permanent I1 to M2s), based on a sample of 30 prehistoric Amerindians with complete and unworn dentitions. There is nearly a tenfold variation in frequency of defects by tooth, ranging from 0.13 per mandibular second molar to 1.27 per maxillary central incisor. The six anterior teeth average between 0.70 and 1.27 defects/tooth, whereas the eight posterior teeth average between 0.43 and 0.13 defects/tooth. Earlier developing teeth, such as incisors, have earlier peak frequencies of defects (2.0-2.5 years), while later developing teeth, such as second molars, have subsequent peak frequencies (5.0-6.0 years). These variations are relevant when comparing hypoplasia data based on different teeth. Differences in hypoplasia frequencies among teeth are not solely due to variation in time of crown development, as is usually reported. Rather, there is evidence for biological gradients in susceptibility to ameloblastic disruption. Anterior teeth are more hypoplastic than posterior teeth. More developmentally stable "polar" teeth are more hypoplastic than surrounding teeth. Polar teeth may be more susceptible to hypoplasias because their developmental timing is less easily disrupted. In all teeth, hypoplasias are most common in the middle and cervical thirds. Crown development and morphological factors, such as enamel prism length and direction, may influence the development and expression of enamel surface defects.     

The dentition of the "old man" of La Chapelle-aux-Saints and inferences concerning Neandertal behavior

It has been suggested that the fossil Neandertal from La Chapelle-aux-Saints was so toothless that he would have had to have his food pre-chewed or otherwise prepared for him. This has also led to the inference that a high level of altruistic social behavior was characteristic of Neandertals. This appears to be in keeping with a current trend among anthropologists to upgrade the cultural and evolutionary status of Neandertals. Close examination of the recovered teeth and the condition of the alveoli indicates that the "old man" of La Chapelle-aux-Saints had upper and lower incisor, canine and premolar teeth on the left side intact and probably in occlusion, and that the same was true of these teeth in the right maxilla. Mandibular incisors, canine, and first premolar had probably been lost to a tumor or abscessing on the right side, but this pathology may have developed near the time of death. The right mandibular second premolar was probably functional, although tilted similarly to the intact premolar on the left. It is very unlikely that the individual was unable to chew food. The dentition thus gives no reliable evidence of altruistic behavior by his cohorts. This study may also relate to hypotheses concerning the ancestry of anatomically modern humans.     

Some observations on chlorophyll(ide) synthesis by isolated etioplasts.

1. A modified procedure for the isolation of etioplasts from dark-grown barley is described and the regeneration of phototransformable protchlorophyll(ide) was demonstrated in the isolated plastids. 2. On exposure of the etioplasts to a long-term flash illumination, chlorophyll(ide) synthesis from a precursor pool, which includes all the protochlorophyllide, was demonstrated. 3. Added delta-aminolaevulinic acid failed to be significantly incorporated into chlorophyll(ide) in the etioplasts despite its extensive incorporation into porphyrin precursors of chlorophyll and haem compounds. The findings are discussed in terms of the inability of etioplasts to carry out the metal-insertion step in chlorophyll synthesis. 4. An elevated chlorophyll(ide) concentration was attained in the etioplasts by increasing the size of the utilizable precursor pool by pre-feeding whole plants with delta-aminolaevulinic acid, isolating the etioplasts and subjecting them to the flash illumination.     

First Record of Rosellinia desmazieresii on Scots Pine and its Association with Disease in Poland

Rosellinia desmazieresii was found for the first time on a tree of Scots pine. It occurred on a dying tree in a mixed Scots pine-oak plantation in Poland. The fungus girdled the base of the trunk, where perithecia were produced abundantly. The fungus was evidently the cause of the tree's poor growth and ultimate death.     

Dominant diatoms in the interglacial lake sediments of the Middle Pleistocene in Central and Eastern Poland

Diatom studies carried out in Central and Eastern Poland have shown a diversified composition and considerable changes of relative frequency of dominant diatoms in profiles of lake sediments of the Mazovian and Ferdynandovian interglacials. Cyclotella spp. are dominant in a large part of the sediment profiles at Adamówka, awki-7 and Wola Grzymalina-59 and, at Krpiec and Podlodów, Stephanodiscus is also common while at Biaa Podlaska and Falcice, Aulacoseira is most abundant. Cyclotella comta var. lichvinensis and C. vorticosa are the typical diatoms in the Mazovian Interglacial. In the sediments representing the Ferdynandovian Interglacial, the characteristic diatoms are Cyclotella cf. reczickiae and the Stephanodiscus rotula/niagarae complex.     

Diurnal variation of chosen airborne pollen at five sites in Poland

The aerobiological investigations were carriedout at five sites located in different climaticand geobotanical regions in Poland. The diurnalperiodicity of Alnus, Betula, Secale,Poaceae, Urtica, and Artemisia wasstudied during two successive years. The taxawere chosen on the basis of pollen grainabundance and allergenity. The pollen wascollected with a Burkard spore trap. Twelvetransversal transverses of microscope slidescorresponding to two-hour periods wereanalysed. The diurnal variations ofPoaceae, Alnus and Betula were irregularand varied between sites and years; highconcentrations were observed at different hoursof the day and night. Diurnal concentrations of Secale, Urtica and Artemisia hadonly one maximum in the middle of the day,constant between sites and years. The lowestconcentrations were observed between eveningand early morning. There was no close relationbetween the time of the liberation ofAlnus, Betula and Poaceae pollen and thetime of the maximum pollen counts. There was aseveral hour delay observed between the timeof Secale pollen liberation and maximumconcentration of airborne pollen.     

Communities of oligochaetes in mountain streams of Poland

This study compares the structure of oligochaete communities in mountain streams of Poland. These streams can be divided into three groups. First, those dominated by the Enchytraeidae (Mesenchytraeus armatus), second where the Naididae, Nais bretscheri, Nais alpina, Nais communis or Nais variabilis prevail and third, where the Lumbriculidae, represented by Stylodrilus heringianus, and in one case by Stylodrilus parvus, are dominant. The nature of the stream bottom is the main factor determining the structure of the community, but geographic location is also important.     

Effect of urbanization on centipede (Chilopoda) diversity in the Wielkopolska-Kujawy Lowlands of western Poland

Over fifty years of research data from various sources were compiled and analyzed in order to determine the effect of urbanization on centipede diversity in the Wielkopolska-Kujawy Lowlands of western Poland. Urbanization has had a significant effect on species composition and community structures. However, it has not reduced overall species richness and diversity in the centipede fauna. The centipede fauna from built-up areas was found to be rich and varied. The habitats with the highest levels of species richness were the city of Poznań and the beech forests in the surrounding region.     

Mycopathogens of Mites in Poland - A Review

Studies on diseases of mites caused by entomopathogenic fungi have been undertaken in Poland about a half a century later than in West European countries. Nevertheless, during the last 30 years almost 40 species of arthropod pathogenic fungi have been identified, among them 23 species of Entomophthorales, 12 species of Hyphomycetales and four species of ectoparasitic Laboulbeniales. The most common are representatives of the genus Hirsutella , found both on phytophagous and parasitic or predaceous mites. Percentage infection by H. thompsonii in populations of some tarsonemid and eriophyid mites increases slowly from the end of spring reaching a maximum of 30-60% in August-September. Neozygites floridana is a common entomophthoralean species causing epizootics in spider mite populations; infection also peaks in late summer and autumn. The most numerous fungal taxa have been identified from the resting spores produced internally within the body of the host and show features of the genus Tarichium . From the total number of the taxa recorded within these studies, 22 were described as species new to science. Current research on invertebrate pathology in Poland includes many groups of mites and among their pathogens fungal diseases seem to be the most common.     

Ambrosia pollen in the air of Lublin, Poland

Studies on Ambrosia pollen concentrations were carried out in Lublin in the period 1995–2004. The effects of a number of meteorological factors were analysed. In the first period of the study, the gravimetric method was used (1995–1999), while in the second period, the volumetric method was applied. The results show an increasing trend in the amount of airborne pollen. The Ambrosia pollen season in Lublin lasts from August to October. Over a period of 5 years, the highest number of pollen grains was recorded in September (53%), followed by August (44%) and October (3%). There were wide variations in annual totals. The annual total pollen counts was 167–1180 grains, with the peak value in 2002. Maximum daily pollen concentrations (56–312 pollen grains m⁻³) were recorded in the first half of August and in the first half of September. On the days when high Ambrosia pollen concentrations occurred, the temperature was above 21°C and the winds were mainly from the southeast, south and east. Maximum intradiurnal concentrations of pollen grains occurred in the afternoon hours. These results indicate, to some degree, that Ambrosia pollen is transported for long distances before descent.     

Study of dentition in lizards from Gran Ganaria Island (Canary Islands) and its ecological and evolutionary significance

The dentition of Gallotia stehlini from one extant and two subfossil populations dated as 4000 and 2000 years before present was studied. Body measurements were similar in the two subfossil populations, but much greater than the largest sizes observed today in G. stehlini. The morphology of the dental cusps in this G. stehlini differs greatly from that of other Lacertidae, including other congeneric Canarian species; this has been connected with a vegetarian diet. A decrease in heterodonty with size of the animal is also seen which contrasts strongly with the models observed in the Mediterranean lacertid lizards.