72,425 research outputs found

    Revision of Dadagulella gen. nov., the “Gulella radius group” (Gastropoda: Streptaxidae) of the eastern Afrotropics, including six new species and three new subspecies

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    The genus Dadagulella gen. nov. is described to include 16 species of small, dentate, ovateacuminate Afrotropical snails. An identification key is provided and biogeography, anatomy and systematics are discussed. The type species is the Kenyan D. radius (Preston, 1910) comb. nov., whose name has informally been used for part of the group in the past. Substantial intraspecific variation occurs in three species: D. radius itself, D. browni (van Bruggen, 1969) comb. nov. and D. minuscula (Morelet, 1877) comb. nov. (= Ennea fi scheriana Morelet, 1881) (non Gulella minuscula Emberton & Pearce, 2000) . We recognise subspecies within each of these: D.radius radius (Preston, 1910) comb. nov., D. r. calva (Connolly, 1922) comb. et stat. nov., D. browni browni (van Bruggen, 1969) comb. nov., D. b. mafi ensis subsp. nov., D. b. semulikiensis subsp. nov., D. minuscula minuscula (Morelet, 1877) comb. nov., D. m. mahorana subsp. nov. Six new Tanzanian species are described: D. cresswelli sp. nov., D. delta sp. nov., D. ecclesiola sp. nov., D. frontierarum sp. nov., D. minareta sp. nov., and D. pembensis sp. nov. The genus includes seven other previously described species: D. cuspidata (Verdcourt, 1962) comb. nov.; D. rondoensis (Verdcourt, 1994) comb. nov.; D. conoidea (Verdcourt, 1996) comb. nov.; D. selene (van Bruggen & Van Goethem, 1999) comb. nov.; D. meredithae (van Bruggen, 2000) comb. nov.; D. nictitans (Rowson & Lange, 2007) comb. nov.; and D. delgada (Muratov, 2010) comb. nov

    Innovation in prediction planning for anterior open bite correction

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    This study applies recent advances in 3D virtual imaging for application in the prediction planning of dentofacial deformities. Stereo-photogrammetry has been used to create virtual and physical models, which are creatively combined in planning the surgical correction of anterior open bite. The application of these novel methods is demonstrated through the surgical correction of a case

    Plesippus francescana (Frick) from the late Pliocene, Coso Mountains, California, with a review of the genus Plesippus

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    Two mammalian types, occurring in a late Pliocene fauna from the Coso Mountains, California, have already been described. Among the more abundant forms in this assemblage are the horses of the genus Plesippus. These are of particular interest not only for purposes of correlation of the geologic horizon in which they occur, but also because of their phylogenetic relationships. Opportunity is taken therefore to make a comparative study of characters of the species from the Coso Mountains with reference to nearly related forms found in beds of similar age and to define more clearly, than has been previously attempted, the position of Plesippus in the lineage of the horse group

    On a model mechanism for the spatial patterning of teeth primordia in the Alligator

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    We propose a model mechanism for the initiation and spatial positioning of teeth primordia in the alligator,Alligator mississippiensis. Detailed embryological studies by Westergaard & Ferguson (1986, 1987, 1990) show that jaw growth plays a crucial role in the developmental patterning of the tooth initiation process. Based on biological data we develop a reaction-diffusion mechanism, which crucially includes domain growth. The model can reproduce the spatial pattern development of the first seven teeth primordia in the lower half jaw ofA. mississippiensis. The results for the precise spatio-temporal sequence compare well with detailed developmental experiments

    New early Eocene tapiromorph perissodactyls from the Ghazij Formation of Pakistan, with implications for mammalian biochronology in Asia

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    Early Eocene mammals from Indo-Pakistan have only recently come under study. Here we describe the first tapiromorph perissodactyls from the subcontinent. Gandheralophus minor n. gen. and n. sp. and G. robustus n. sp. are two species of Isectolophidae differing in size and in reduction of the anterior dentition. Gandheralophus is probably derived from a primitive isectolophid such as Orientolophus hengdongensis from the earliest Eocene of China, and may be part of a South Asian lineage that also contains Karagalax from the middle Eocene of Pakistan. Two specimens are referred to a new, unnamed species of Lophialetidae. Finally, a highly diagnostic M3 and a molar fragment are described as the new eomoropid chalicothere Litolophus ghazijensis sp. nov. The perissodactyls described here, in contrast to most other mammalian groups published from the early Eocene of Indo-Pakistan, are most closely related to forms known from East and Central Asia. Tapiromorpha are diverse and biochronologically important in the Eocene there and our results allow the first biochronological correlation between early Eocene mammal faunas in Indo-Pakistan and the rest of Asia. We suggest that the upper Ghazij Formation of Pakistan is best correlated with the middle or late part of the Bumbanian Asian Land-Mammal Age, while the Kuldana and Subathu Formations of Pakistan and India are best correlated with the Arshantan Asian Land-Mammal Age

    Morphological separation of the Central European Trochosa females (Araneae, Lycosidae)

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    Adult females of the five Central European wolf spiders Trochosa hispanica Simon, 1870, T. robusta (Simon, 1876), T. ruricola (De Geer, 1778), T. spinipalpis (F. O. P.-Cambridge, 1895), and T. terricola Thorell, 1856 were morphologically analysed. We defined sets of continuous and binary (presence/absence) variables. Continuous data of various epigynal and carapace dimensions were subjected to Principal Components Analysis (PCA). Using the PC loadings each individual was plotted along the PC axis in order to find gaps/overlaps between the species. The binary data sets were subjected to Hierarchical Cluster Analysis (HCA) in order to find characters that clearly separate the five Trochosa species. Using PCA only individuals of T. robusta and T. ruricola and of T. robusta and T. hispanica could be separated from each other. Using HCA all five species could clearly be separated by epigynal and vulval characteristics

    Minimally invasive orthodontics: elastodontic therapy in a growing patient affected by Dentinogenesis Imperfecta

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    AIM: The aim of the study was to report the use of an elastodontic therapy in a growing patient affected by Dentinogenesis Imperfecta, second class malocclusion, deep bite and lower arch crowding from the deciduous dentition to permanent one. CASE REPORT: At first, the 5-year-old patient was treated with an elastodontic device known as "Nite-Guide". When the patient was 7 years old, during her first permanent molars and incisors eruption and after optimal house-practices, an Occlus-o-Guide Series G was placed at night and on daylight (two hours a day) performing exercises aimed to activate facial muscles and facilitate the deep bite reopening. At 9 years of age, with totally deep bite resolution, she used the Occluso-Guide only at night to hold down previous results and follow patient's dental growth. At 11 years of age, after successful teeth switching, we prescribed an Occlus-o-Guide Series N, which is functional for permanent dentition and guaranteed an eruptive guide for last dental elements. CONCLUSIONS: This clinic case could be considered an example of approach for all those patients with systemic and/or dental diseases that do not allow adequate dental retention, which is necessary for most orthodontic appliances; elastodontic devices do not require adequate dental retention and define a minimum intervention on the surfaces of the teeth

    Consequences of Tooth Loss on Oral Function and need for Replacement of Missing Teeth Among Patients Attending Muhimbili Dental Clinic

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    Tanzanian oral health services constitute mainly of tooth extractions. Consequently, individuals susceptible to dental caries and periodontal diseases will have a substantial number of missing teeth, which can affect oral function. The main objective of this study was to determine the consequences of tooth loss on the oral function and need for replacement of lost teeth among patients seeking treatment at the School of Dentistry MUHAS. During a period of three months, patients seeking dental treatment at the School of Dentistry were recruited for the study. Criteria included age of 20 years and above with one or more missing teeth except for third molars. Participants were interviewed for demographic information, chewing ability, symptoms of temporomandibular disorder and perceived need for replacement of missing teeth. Afterwards the subjects were examined to asses: caries status, tooth mobility, occlusal tooth wear, over eruption of unopposed teeth, and signs of temporomandibular disorders. Data was analyzed using Statistical Package for Social Sciences SPSS 16. For comparison of proportions, chi-square analysis and t test were used. A linear regression analysis was performed, with the chewing ability score as the dependent variable and number of POP as the independent variable A total of 361 subjects with mean age of 40.2 years (s.d. = 14.2, range = 20-93 years) were recruited into the study. About half 175 (48.5%) of the subjects reported some difficulty with chewing. Generally the fewer the occluding pairs present the greater the difficulty in chewing observed. Subjects with more than 6 posterior occlusal pairs appeared to have little problem in chewing across the whole range of foods. The frequency of signs and symptoms of TMD and excessive tooth wear increased with decreasing number of posterior occluding pairs, being more evident in subjects with less than 3 posterior occlusal pairs remaining. Over a third of the participants had one or more teeth with severe overeruption but none reported impairment of oral function. More than half of the subjects needed replacement for missing teeth. From this study, it is concluded that tooth loss leading to a dentition of 5 to 6 occlusal pairs impairs chewing of hard foods but not soft foods. Extensive loss of teeth leading to less than 3 POP is associated with increased symptoms of TMD and excessive vii tooth wear of occluding teeth. Need for replacement of missing teeth is high for both anterior and posterior regions with the cost of dentures being the main barrier to replacement of missing teeth. Dental personnel should make an effort to identify individuals with risk of tooth loss in order to retain at least 6 well-distributed posterior occlusal pairs. Dental laboratory services need improvement in order to be able to provide quality replacement of missing teeth at affordable costs. Further long-term multicenter studies to evaluate the consequence of tooth loss and assist in giving a more accurate projection needs for dentures nationwide are required

    The Hazen Mammoth (Mammuthus columbi), Prairie County, Arkansas

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    In May 1965, mammoth remains were exposed during the excavation of a borrow pit for construction of Interstate Highway 40, 2 mi northeast of Hazen, Prairie County, Arkansas. The proboscidian remains consisted of a skull with tusks, mandibles, atlas and other skeletal elements. The vertebra material was scattered over approximately 150 m (1,600 sq ft) but was confined to a layer of red clayey-silt 6.7 m (22 ft) below the surface. No additional fauna or flora was recovered. The mammoth remains are referred to Mammuthus columbi (Falconer, 1857) on the basis of characteristics of the dentition, particularly the comparison of index of hypsodonty to functional plate density. Mammuthus columbi was widely distributed in southeast North America during the late part of the Pleistocene Epoch (Sangamon-Wisconsin Stages)

    The Correlation of Dental Arch Width and Ethnicity

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    This study sought to demonstrate a correlation between arch width, ethnic background, individual height, weight, and whether orthodontic treatment had been rendered. Conclusions revealed that arch widths were significantly larger (p= 0.002 for the mandible and p= 0.008 for the maxilla) in non-Whites than in Whites. In addition, arch widths of the mandible were significantly larger in individuals who had had orthodontic treatment compared to those who had not (p=0.005). This did not carry through to those arch widths in the maxilla of orthodontic versus nonorthodontic care (p=0.258)
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