The evolutionary history of mammals, when including extinct taxa, is mainly reconstructed using tooth morphology and employs terminology based on non-monotreme mammals. Although adult monotremes are edentulous, juvenile platypuses have teeth that can be compared with extinct monotremes, but terminology can be a barrier to efficient comparison to non-monotreme mammals. Deciduous teeth and thickened epithelial plates of the extant platypus, Ornithorhynchus anatinus, are sparsely figured in the literature. New imagery of those teeth and plates from high-resolution x-ray computed tomography and scanning electron microscopy contribute to the understanding of mammal evolution and the unique morphology of platypus teeth. The teeth of the juveniles are highly variable, but early-forming features (major cusps and transverse valleys) are stable enough for comparison. Transverse lophs on monotreme teeth contain complexity not reflected in cusps alone, unlike therian mammals. These differences reinforce the need for caution when applying dental terminology that originally was produced for therian mammals. New imagery highlights potential phylogenetically informative morphology in the pulp cavity and roots. As the roots of the juvenile teeth degenerate, the epithelium below the teeth thickens into epithelial plates. Structures in the epithelial plates are broadly similar to those found in the keratin plates. New images of the epithelial plates offer insight into a series of tubes concentrated under the juvenile teeth. The tubes are a continuous conduit to the plate surface and may serve a sensory function or result from the ever-growing nature of the epithelial plate. / text

Работа посвящена созданию англо-русского частотного словаря стоматологических терминов на базе корпуса текстов с применением метода лемматизации. Теоретическая часть исследования, содержащая информацию об особенностях составления частотных словарей, подробный анализ терминосистемы в сфере стоматологии и её перевода, послужила базой для практической работы. Благодаря лемматизации и последующей ручной работы в частотный словарь попала только специализированная лексика в сфере стоматологии, что способствовало сокращению объёма частотного словаря и повышению его качества. / The paper is devoted to the development of an English-Russian frequency dictionary of dental terms using the lemmatization method based on the corpus of texts developed in the Sketch Engine program. The theoretical part containing information about the peculiarities of compiling frequency dictionaries, a detailed analysis of the dental terminology and its translation served as the basis for the practical work. Applying the method of lemmatization, we included only dental terminology in the frequency dictionary, without taking into account the commonly used vocabulary, which contributed to reducing the volume of the frequency dictionary and improving its quality.