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Objective: To assess the 2D and 3D natural symmetry of the maxillary incisors. Materials and methods: Maxillary alginate impressions were taken of 59 young adult volunteers. Gender, orthodontic treatment history, and dominant hand were collected. For 2D analysis, a digital caliper was used for measurements on maxillary casts. For 3D analysis, the casts were scanned using a lab scanner, and the labial surface symmetry of contralateral incisors was evaluated. Mann–Whitney tests and Student's t‐test were performed, α = 0.05. Results: Results indicated a lack of identical lengths among contralateral central or lateral incisors, with minimal occurrences of identical width measurements. 68% of central incisors and 73% of lateral incisors showed differences in length exceeding 0.2 mm. Central incisors showed more similarities than lateral incisors in width, with 61% central incisors and 47% lateral incisors having differences under 0.2 mm. The differences between highly asymmetrical contralateral teeth are situated at the transitional lines. The influence of sexual dimorphism, orthodontic factors, and the dominant hand on incisors' symmetry was not statistically significant. Conclusions: 2D and 3D symmetry of the natural maxillary incisors are rare. 3D symmetry remains consistent across orthodontic treatment status, gender, and dominant hand, suggesting its independence from such parameters. Clinical significance: To achieve a natural and aesthetic smile rehabilitation, the symmetry of the maxillary incisors must be well understood. In our study, 2D and 3D symmetry of the maxillary incisors occurred rarely, but central incisors showed more similarities than lateral incisors in width, with differences under 0.2 mm. On the other hand, differences between highly asymmetrical contralateral teeth are situated at the transitional lines. These conclusions should be included in further computer‐assisted three‐dimensional smile designs. [ABSTRACT FROM AUTHOR]

Despite their relative abundance, members of the family Hypertragulidae (Artiodactyla, Mammalia) have proved a conundrum regarding species diversity in the Turtle Cove Member (Oligocene) of the John Day Formation, located in central and eastern Oregon. Three species and two separate genera are described in the area, but previous research lacks statistical support for this level of variation. We use coefficients of variation (V) on measurements of dentition and astragali of hypertragulid specimens designated Hypertragulus hesperius, Hypertragulus minutus, and Nanotragulus planiceps as a metric for determining whether there were multiple species present in the population. Asymptotic and modified signed-likelihood ratio V equality tests show that V values of anterior-posterior molar length and transverse molar width vary significantly when comparing single species of modern ecological analogs (Muntiacus muntjak, Muntiacus reevesi, and Tragulus javanicus) to groupings of a combined population. However, the V equality tests on dental and postcranial measurements yield almost no significant results when comparing variation in the extinct John Day hypertragulids to an extant population comprised of a single species. Similar comparisons between astragali measurements of hypertragulids and T. javanicus express no significant difference in the level of variation from the combined population to a modern single species. The low level of variation in the hypertragulids and the lack of differentiation between dental characters of individuals does not statistically support the hypothesis that there were multiple species present in the population, suggesting either that cryptic species may be present but impossible to identify without soft tissue remains, or there may have been taxonomic over-splitting of a single hypertragulid species in the John Day region.

Despite their relative abundance, members of the family Hypertragulidae (Artiodactyla, Mammalia) have proved a conundrum regarding species diversity in the Turtle Cove Member (Oligocene) of the John Day Formation, located in central and eastern Oregon. Three species and two separate genera are described in the area, but previous research lacks statistical support for this level of variation. We use coefficients of variation (V) on measurements of dentition and astragali of hypertragulid specimens designated Hypertragulus hesperius, Hypertragulus minutus, and Nanotragulus planiceps as a metric for determining whether there were multiple species present in the population. Asymptotic and modified signed-likelihood ratio V equality tests show that V values of anterior-posterior molar length and transverse molar width vary significantly when comparing single species of modern ecological analogs (Muntiacus muntjak, Muntiacus reevesi, and Tragulus javanicus) to groupings of a combined population. However, the V equality tests on dental and postcranial measurements yield almost no significant results when comparing variation in the extinct John Day hypertragulids to an extant population comprised of a single species. Similar comparisons between astragali measurements of hypertragulids and T. javanicus express no significant difference in the level of variation from the combined population to a modern single species. The low level of variation in the hypertragulids and the lack of differentiation between dental characters of individuals does not statistically support the hypothesis that there were multiple species present in the population, suggesting either that cryptic species may be present but impossible to identify without soft tissue remains, or there may have been taxonomic over-splitting of a single hypertragulid species in the John Day region. [ABSTRACT FROM AUTHOR]

Purpose: To improve smile esthetics, clinicians should comprehensively analyze the face and ensure that the sizes selected for the maxillary anterior teeth are compatible with the available anthropological measurements. The inter commissural (ICW), interalar (IAW), intermedial-canthus (MCW), interlateral-canthus (LCW), and interpupillary (IPW) widths are used to determine the width of maxillary central incisors (CW). The aim of this study was to develop an automated approach using machine learning (ML) algorithms to predict central incisor width in a young Turkish population using anthropological measurements. This automation can contribute to digital dentistry and clinical decision-making. Methods: In the initial phase of this cross-sectional study, several ML regression models--including multiple linear regression (MLR), multi-layer-perceptron (MLP), decision-tree (DT), and random forest (RF) models--were validated to confirm the central width prediction accuracy. Datasets containing only male and female measurements, as well as combined were considered for ML model implementation, and the performance of each model was evaluated for an unbiased population dataset. Results: Compared with the other algorithms, the RF algorithm showed improved performance for all cases, with an accuracy of 96%, which represents the percentage of correct predictions. The plot reveals the applicability of the RF model in predicting the CW from anthropological measurements irrespective of the candidate's sex. Conclusions: These results demonstrated the possibility of predicting central incisor widths based on anthropometric measurements using ML models. The accurate central incisor width prediction from these trials also indicates the applicability of the proposed model to be deployed for enhanced clinical decision-making. [ABSTRACT FROM AUTHOR]

The Paucituberculata are a group of marsupials endemic to South America, recorded from the Early Eocene to the present. In terms of taxonomy and qualitative morphology, paucituberculatans are a quite diverse and disparate group, especially considering their extinct representatives. This study aimed to investigate the variability in the quantitative morphology of paucituberculatans in the context of the largest morphometric study of the group performed to date. Due to the fragmentary fossil record, this work focused on lower dental morphology which allowed us to compare around 95% of paucituberculatan species through the measurement and analysis of almost 1500 specimens. Dental measurements of 27 variables were analysed by Principal Component Analysis and Partial Least Squares correlation as exploratory methods. As a result, it is shown that the continuous variability is expressed not only in size differences among species but also in morphological variability of individual teeth, and differences in size and proportions along the molar row. We conclude that paucituberculatans are a group of important morphological diversity regarding quantitative morphology. Many of the quantitative taxonomic features discussed in the literature were corroborated in this study. In addition, we discussed potential evolutionary and palaeoecological implications of this study, highlighting prospects for future studies. [ABSTRACT FROM AUTHOR]

Simple Summary: Archaeozoological investigation of the horse remains discovered in Alba Iulia-CX 143 complex of the La Tène period reveals the existence of a small-sized male horse (Equus caballus) of 1200–1300 mm in height with slender extremities that died at the age of 7–8 years with no evident paleopathological changes characteristic to horseback riding but showing distinctive elements of bit wear. The present paper deals with the archaeozoological investigation carried out on a horse skeleton discovered in a Late Iron Age La Tène tomb (coded CX 143) in Alba Iulia, Romania. The paper presents all the results of the investigation, with a description of finds, adding a detailed assessment of the dentition with some interesting conclusions on the usage of a horse bit and the possible consequences of this use. The morphological features of the horse indicate a 7–8-year-old male individual, with a recalculated height of 1200–1300 mm. What is also stressed in the investigated sample is the lack of the characteristic pathological lesions typical for horseback riding but showing distinctive elements of bit wear. A comparative perspective over the few findings from the same period is provided to ensure the framing of the identified individual into the much larger historical context. [ABSTRACT FROM AUTHOR]

Bats appear in the fossil record on multiple continents during the early Eocene. More than seventy Eocene bat species have been named to date, including stem bats, probable members of crown families, and others of uncertain affinity. Most phylogenetic analyses of Eocene bat relationships have focused on the handful of taxa known from nearly complete skeletal material, whereas the taxonomic relationships of more incomplete fossils have been based largely on phenetic similarities. Here we evaluate the evolutionary relationships of over 60 species of Eocene bats—including many taxa known only from fragmentary craniodental remains—in an explicitly phylogenetic context. Our analysis is based on nearly 700 morphological characters scored in 82 taxa, including 20 extant species representing all living bat families other than Pteropodidae. We found that phylogenetic relationships of Eocene bats are more complex than previously thought. Numerous families (e.g., †Archaeonycteridae, †Mixopterygidae, †Palaeochiropterygidae) and genera (e.g., †Archaeonycteris, †Icaronycteris, †Carcinipteryx) were found to be non-monophyletic as previously recognized, requiring adjustments to chiropteran taxonomy. Four major clades of stem bats were recovered in our analyses. †Microchiropteryx folieae (~ 54 Ma, India) was recovered as the earliest crown bat, occurring as the most basal lineage of Vespertilionoidea, whereas many putative crown bats were recovered among stem Chiroptera. †Tachypteron franzeni was found to be a crown bat in our analyses, as in previous studies, but it was recovered unexpectedly as a stem miniopterid. The phylogenetic relationships presented here represent the most comprehensive analysis of Eocene bat relationships completed to date, substantially improving our understanding of the position of many fossil taxa within Chiroptera and providing a foundation for future analyses of bat evolution. [ABSTRACT FROM AUTHOR]

Objective: The study aimed to assess and compare both the chewing efficiency and the contact area between class I and class II of Angle’s malocclusions. Material and methods: A total of 120 individuals aged between 19 and 30 years were examined and were divided into two groups according to Angle’s class (Class I and class II). The chewing efficiency was quantified using the ViewGum software and two-colored chewing gum. The contact area was quantified using modeling wax and MATLAB software. All data were collected, then, analyzed using SPSS software 21. Data normality was checked through kurtosis test. Descriptive results were calculated. Matched sample t-tests were used to compare chewing efficiency measurements between right and left sides. Independent t-tests were used to compare chewing efficiency and the contact area between class I and class II of Angle’s malocclusions. Linear regression and Pearson correlation were used to assess the correlation between chewing efficiency and the contact area. The significance level was fixed at p = 0.05. Results: For group 1, the mean hue value on both sides was 0.086 ± 0.058. For group 2, it was 0.095 ± 0.055. The difference between both groups was statistically significant (p = 0.03). For group 1, the mean contact area was 49.91 ± 21.47 mm2. For group 2, it was 51.42 ± 19.76 mm2. The difference was statistically not significant (p = 0.4). The correlation between the contact area and the chewing efficiency in both groups was statistically significant and it was negative (in class I p = 0 and R = -0.616; in class II p = 0.01 and R = −0.408). Conclusion: The Chewing is better for patients with Angle’s Class I malocclusion. The contact area is higher. Larger occlusal contact area leads to higher masticatory efficiency. Further studies should be conducted.

The study aimed to assess and compare both the chewing efficiency and the contact area between class I and class II of Angle's malocclusions. A total of 120 individuals aged between 19 and 30 years were examined and were divided into two groups according to Angle's class (Class I and class II). The chewing efficiency was quantified using the ViewGum software and two-colored chewing gum. The contact area was quantified using modeling wax and MATLAB software. All data were collected, then, analyzed using SPSS software 21. Data normality was checked through kurtosis test. Descriptive results were calculated. Matched sample t-tests were used to compare chewing efficiency measurements between right and left sides. Independent t-tests were used to compare chewing efficiency and the contact area between class I and class II of Angle's malocclusions. Linear regression and Pearson correlation were used to assess the correlation between chewing efficiency and the contact area. The significance level was fixed at p = 0.05. For group 1, the mean hue value on both sides was 0.086 ± 0.058. For group 2, it was 0.095 ± 0.055. The difference between both groups was statistically significant (p = 0.03). For group 1, the mean contact area was 49.91 ± 21.47 mm2. For group 2, it was 51.42 ± 19.76 mm2. The difference was statistically not significant (p = 0.4). The correlation between the contact area and the chewing efficiency in both groups was statistically significant and it was negative (in class I p = 0 and R = -0.616; in class II p = 0.01 and R = −0.408). The Chewing is better for patients with Angle's Class I malocclusion. The contact area is higher. Larger occlusal contact area leads to higher masticatory efficiency. Further studies should be conducted. [ABSTRACT FROM AUTHOR]

Heba Alzer,1 Noor H Ismail,1 Firas Alsoleihat1,2 1Department of Restorative Dentistry, School of Dentistry, The University of Jordan, Amman, Jordan; 2Department of Restorative Dentistry and Basic Medical Sciences, Faculty of Dentistry, University of Petra, Amman, 11196, JordanCorrespondence: Heba Alzer, Department of Restorative Dentistry, School of Dentistry, The University of Jordan, Amman, 11942, Jordan, Tel +96265355000-23537, Fax +962 6 5355 52, Email h.alzer@ju.edu.joBackground: Learning fine motor skill is central to preclinical dental education. Dental students are introduced to anatomical tooth carving to facilitate the development of their fine motor skill and manual dexterity. Various carving technique exists, such as wax build-up, and geometric (block carving technique). Since substantial laboratory Time and instructors’ effort are required to teach students the desired techniques, blended learning approach via pre-recorded demonstration may improve the teaching and learning efficiency of anatomical tooth carving. For years, we used the Geometric method to teach preclinical dental students to carve down tooth sculptures after performing live demonstrations for them. Multiple practical laboratory demonstrations are necessary to deepen the student’s comprehensive understanding of dental anatomical features and teach them correct instrumentation; this is time-consuming and challenging due to limited laboratory hours and limited view field. Accordingly, in 2016 the teaching staff created videos for tooth drawing, carving, and identification, and uploaded them to the students’ university platform. Years later, we decided to perform this retrospective study.Objective: To assess the enhancement in students’ tooth carving skills after implementing blended learning with video demonstrations.Methods: The student’s total grades were used for comparative purposes. The students’ total grades between 2010 and 2019 were collected and categorized into two groups: Group 1 (n=858), which learned tooth carving by the Geometric method after live demonstrations, and Group 2 (972), which benefited from blended learning with video demonstrations in learning. The two groups’ mean, median, mode, Percentile 75, and Percentile 90 were compared.Results: Group 2 showed higher grades than group 1, and the differences between the two groups’ mean and median were statistically significant p< 0.001. Moreover, the mode, P75 and P90 favored group 2.Conclusion: Results show that blended learning with video demonstrations enhanced the achievements of dental students in tooth carving.Keywords: dental anatomy, blended learning, video demonstrations, dental morphology, tooth carving, dental education

Various digital technologies are used as learning media in the educational process to enhance the morphological understanding of teeth. This study aimed to investigate the educational impact of augmented reality content in the practice of tooth morphology. Using a survey, we assessed learning interest, learning flow, and learning satisfaction in the experimental group (n=26) using augmented reality content and the control group (n=26) using traditional plastic models. The collected data were analyzed using the statistical analysis program SPSS (v25.0, IBM, NY, USA). Group differences and pre-post analysis results were examined. Results in the experimental group showed all variables as rated high and a statistically significant difference. This signifies the educational efficacy of augmented reality applications in dental morphology practical training. Augmented reality content is recommended as a supplementary learning tool to traditional methods in tooth morphology practice. [ABSTRACT FROM AUTHOR]

Histone methylation assumes a crucial role in the intricate process of enamel development. Our study has illuminated the substantial prevalence of H3K4me3 distribution, spanning from the cap stage to the late bell stage of dental germs. In order to delve into the role of H3K4me3 modification in amelogenesis and unravel the underlying mechanisms, we performed a conditional knockout of Ash2l, a core subunit essential for the establishment of H3K4me3 within the dental epithelium of mice. The absence of Ash2l resulted in reduced H3K4me3 modification, subsequently leading to abnormal morphology of dental germ at the late bell stage. Notably, knockout of Ash2l resulted in a loss of polarity in ameloblasts and odontoblasts. The proliferation and apoptosis of the inner enamel epithelium cells underwent dysregulation. Moreover, there was a notable reduction in the expression of matrix-related genes, Amelx and Dspp, accompanied with impaired enamel and dentin formation. Cut&Tag-seq (cleavage under targets and tagmentation sequencing) analysis substantiated a reduction of H3K4me3 modification on Shh, Trp63, Sp6, and others in the dental epithelium of Ash2l knockout mice. Validation through real-time polymerase chain reaction, immunohistochemistry, and immunofluorescence consistently affirmed the observed downregulation of Shh and Sp6 in the dental epithelium following Ash2l knockout. Intriguingly, the expression of Trp63 isomers, DNp63 and TAp63, was perturbed in Ash2l defect dental epithelium. Furthermore, the downstream target of TAp63, P21, exhibited aberrant expression within the cervical loop of mandibular first molars and incisors. Collectively, our findings suggest that ASH2L orchestrates the regulation of crucial amelogenesis-associated genes, such as Shh, Trp63, and others, by modulating H3K4me3 modification. Loss of ASH2L and H3K4me3 can lead to aberrant differentiation, proliferation, and apoptosis of the dental epithelium by affecting the expression of Shh, Trp63, and others genes, thereby contributing to the defects of amelogenesis. [ABSTRACT FROM AUTHOR]

Henkelotherium guimarotae Krebs 1991 is an important Jurassic mammal for understanding therian evolution. We are presenting a new study of extensive, previously undescribed, mandibles and dentitions. The revised dental formula is: I4? or 5?/i4, C1/c1, P4/p4, M6/m7. The canine and premolars show an alternate replacement that ends with M4/m4 eruption, and is followed by a late sequential eruption of the last three lower (m5-7) and last two upper (M5-6) molars. The lower premolars erupted in the following order: p1 → p3 → p2 → p4, and the canine erupted most probably shortly before p4. The timing of the premolar replacement before the late molar eruption is similar to that of Dryolestes leiriensis, and is a characteristic of dryolestidans. Henkelotherium lower molars have subequal roots, a plesiomorphy of non-dryolestidan mammals, and the upper molars are supported by a strong, curved lingual root; a derived character. In the upper molars, the postvallum wear surface is contiguous to the parastyle wear surface of the succeeding molar, which differs from dryolestids. The parastylar lobe of the succeeding molar, and the postvallum of the preceding molar, are imbricated, and can develop strong, continuous wear surfaces, matching the prevallid crest of the lower molar. Henkelotherium differs from dryolestids in having an inflected, shelf-like mandibular angular process with a foramen. This large sample of Henkelotherium shows a significant variation gradient along the molar series, with the strongest wear occurring only in two to three consecutive molars. The extraordinarily long molar row is correlated with the late growth of jaws; and the jaw with late addition of molars sustained an effective mastication, much longer in older adults of dryolestidans than in other Mesozoic stem therians. The late eruption of several more molars after completion of antemolar replacement suggests that dryolestidans had either a longer-lived life, or slower life-history traits, or a combination of both, than crown therians. [ABSTRACT FROM AUTHOR]

The present paper deals with the archaeozoological investigation carried out on a horse skeleton discovered in a Late Iron Age La Tène tomb (coded CX 143) in Alba Iulia, Romania. The paper presents all the results of the investigation, with a description of finds, adding a detailed assessment of the dentition with some interesting conclusions on the usage of a horse bit and the possible consequences of this use. The morphological features of the horse indicate a 7–8-year-old male individual, with a recalculated height of 1200–1300 mm. What is also stressed in the investigated sample is the lack of the characteristic pathological lesions typical for horseback riding but showing distinctive elements of bit wear. A comparative perspective over the few findings from the same period is provided to ensure the framing of the identified individual into the much larger historical context.

Sexual dimorphism, the phenomenon of differences in size, shape, or morphology between males and females of a species, is a well-studied aspect of biology. In this study, we delve into the realm of canine crown sexual dimorphism within the contemporary Croatian canine population. By examining dental morphological differences between male and female dogs, we shed light on the potential underlying factors driving these distinctions. Through detailed anatomical exploration, this article aims to contribute to our understanding of the intricate interplay between genetics, evolution, and environmental factors that shape the dental morphology of dogs. [ABSTRACT FROM AUTHOR]

The interest in the development of dental enamel thickness measurement techniques is connected to the importance of metric data in taxonomic assessments and evolutionary research as well as in other directions of dental studies. At the same time, advances in non-destructive imaging techniques and the application of scanning methods, such as micro-focus-computed X-ray tomography, has enabled researchers to study the internal morpho-histological layers of teeth with a greater degree of accuracy and detail. These tendencies have contributed to changes in established views in different areas of dental research, ranging from the interpretation of morphology to metric assessments. In fact, a significant amount of data have been obtained using traditional metric techniques, which now should be critically reassessed using current technologies and methodologies. Hence, we propose new approaches for measuring dental enamel thickness using palaeontological material from the territories of northern Vietnam by means of automated and manually operated techniques. We also discuss method improvements, taking into account their relevance for dental morphology and occlusion. As we have shown, our approaches demonstrate the potential to form closer links between the metric data and dental morphology and provide the possibility for objective and replicable studies on dental enamel thickness through the application of automated techniques. These features are likely to be effective in more profound taxonomic research and for the development of metric and analytical systems. Our technique provides scope for its targeted application in clinical methods, which could help to reveal functional changes in the masticatory system. However, this will likely require improvements in clinically applicable imaging techniques. [ABSTRACT FROM AUTHOR]

Glirid dental material is described from the Middle Miocene channel fill of the Hambach open-cast lignite mine in northwestern Germany. The fauna Hambach 6C shows a high diversity with seven species in six genera: Glirudinus undosus , Muscardinus thaleri , Muscardinus sansaniensis , Miodyromys aegercii , Paraglirulus werenfelsi , Microdyromys koenigswaldi , and Paraglis astaracensis , which are characteristic taxa in Middle Miocene European localities. Regarding the faunal composition and high diversity, the Hambach 6C assemblage is closest to that of the MN 5 locality Schönenberg in southern Germany, but also shares many taxa with late Middle Miocene faunas. The species richness of glirids, combined with other vertebrate remains in Hambach 6C indicates a warm, humid forested environment during the Mid-Miocene Climate Optimum (MCO). [ABSTRACT FROM AUTHOR]

The South African Early Jurassic morganucodontan Erythrotherium is considered by some authors to be potentially synonymous with Morganucodon, due to similar tooth morphology. However, despite their similar dental morphology, the occlusal pattern of Erythrotherium parringtoni has been described as embrasure occlusion, close to the mode of Megazostrodon rudnerae, rather than that of Morganucodon. In this study the molars of Erythrotherium were re-examined and the two alternative occlusal hypotheses were tested using the Occlusal Fingerprint Analyser (OFA). Morphological comparison of the molars of Erythrotherium parringtoni to those of Morganucodon watsoni showed similarities in cusp height and shape in lingual/buccal views, but the molars and individual cusps of Erythrotherium parringtoni are considerably narrower linguo-buccally, and more gracile. With cusps a and c close together in Erythrotherium parringtoni, cusp positioning differs from that of Morganucodon watsoni and shows similarities to the pattern in Megazostrodon rudnerae. Also, the upper molars of Erythrotherium parringtoni are aligned in a straight row and lack the angle, relative to the longitudinal axis, between the first and second upper molars that is present in Morganucodon watsoni. This results in embrasure occlusion being the only viable occlusal mode for Erythrotherium parringtoni, which was confirmed by the OFA analysis. A Morganucodon-like occlusion would allow only the main cusps a/A to contact their antagonists and thus major gaps would be present, causing considerable reduction of functionality of the dentition. Based on the morphological evidence and the differing occlusal mode, the perpetuation of Erythrotherium parringtoni as a separate genus is confirmed.

Revision of the anthracothere Parabrachyodus hyopotamoides , endemic to the Lower Miocene of the Indian subcontinent and thus far confused with Brachyodus , is made possible by the description of unpublished specimens from the Samane Nala fossil-bearing deposits of the Bugti Hills (Pakistan). This is the first biochronologically constrained occurrence for a comprehensive series of this species. The analysis of cranial and dental morphological variations based on all known specimens of Parabrachyodus allows us to provide diagnostic characters for this monotypic genus. These include a four-crested upper molar protocone unique among artiodactyls and several convergences with subfamily Anthracotheriinae, like the two puzzling distal cristae on the last upper premolar protocone. A phylogenetic analysis at the hippopotamoid level, including Parabrachyodus and the enigmatic genera Telmatodon and Gonotelma (both also endemic to the Bugti Hills), is performed for the first time. These phylogenetically related taxa turn out to be basal to the tribe Merycopotamini, leading us to propose a more inclusive definition of the diagnosis of this tribe. Our results formally establish Elomeryx as the sister-group of Merycopotamini in Bothriodontinae, and definitely locate the early evolutionary history of Merycopotamini on the Indian subcontinent. [ABSTRACT FROM AUTHOR]

Voles from the Genus Microtus are rodents with a subterranean lifestyle. Central Italy is populated by two species of the Genus, the North-Western Microtus savii and the South-Eastern endemic Microtus brachycercus. Although morphometric features able to help distinguish M. savii from M. brachycercus are lacking, a peculiar morphology of the anterior end of the first lower molar is typical, but not exclusive, of M. brachycercus. Since some skulls with a compatible dental morphology were collected from Long-eared owl pellets in Umbria (Central Italy), a genetic assessment was deemed necessary to verify the possible presence of M. brachycercus outside of its known distribution range. Hemimandibles were isolated and used for both genetic and morphometric dental analyses. Despite the fact that this could suggest the presence of a M. brachycercus population, genetic analyses confirmed the species attribution to the M. savii complex, showing peculiar genetic polymorphisms that can either be due to the wide sampling area, represented by the owls' hunting grounds, or to the recent evolutive history of the analysed population. This study, once again, underlines the importance of integrative taxonomy, suggesting the key role of predators as field-assistants to minimize the impact of sampling campaign on natural populations. [ABSTRACT FROM AUTHOR]

The structure, composition, and shape of teeth have been related to dietary specialization in many vertebrate species, but comparative studies on snakes' teeth are lacking. Yet, snakes have diverse dietary habits that may impact the shape of their teeth. We hypothesize that prey properties, such as hardness and shape, as well as feeding behavior, such as aquatic or arboreal predation, or holding vigorous prey, impose constraints on the evolution of tooth shape in snakes. We compared the morphology of the dentary teeth of 63 species that cover the phylogenetic and dietary diversity of snakes, using 3D geometric morphometrics and linear measurements. Our results show that prey hardness, foraging substrate, and the main feeding mechanical challenge are important drivers of tooth shape, size, and curvature. Overall, long, slender, curved teeth with a thin layer of hard tissue are observed in species that need to maintain a grip on their prey. Short, stout, less curved teeth are associated with species that undergo high or repeated loads. Our study demonstrates the diversity of tooth morphology in snakes and the need to investigate its underlying functional implications to better understand the evolution of teeth in vertebrates. [ABSTRACT FROM AUTHOR]

Taxonomic decisions made by palaeontologists are often based on a few morphological features preserved in the fossil material. This practice may sometimes lead to the description of new species based on single specimens, which are, in fact, extreme or aberrant morphological variants of known taxa. Ancient DNA (aDNA) analysis of the Late Pleistocene specimens from the archaeological site Petits Guinards (Creuzier-la-Vieux, Allier, France), described as a new vole Microtus (Sumeriomys) bifrons, did not confirm the species distinctness of the studied population. The genetically examined specimens belonged to Stenocranius anglicus and/or Microtus arvalis, the dominant species at the site. Our findings show that it is risky to describe new fossil taxa on the basis of phenotypic outliers or morphologically aberrant, rare specimens that do not fall within the previously known population variability. We also highlight the importance of ancient DNA in resolving taxonomic and nomenclature problems and classifying fossil mammals of the Late Pleistocene age. [ABSTRACT FROM AUTHOR]

Evolutionary changes in vertebrates are linked to genetic alterations that often affect tooth crown shape, which is a criterion of speciation events. The Notch pathway is highly conserved between species and controls morphogenetic processes in most developing organs, including teeth. Epithelial loss of the Notch-ligand Jagged1 in developing mouse molars affects the location, size and interconnections of their cusps that lead to minor tooth crown shape modifications convergent to those observed along Muridae evolution. RNA sequencing analysis revealed that these alterations are due to the modulation of more than 2000 genes and that Notch signaling is a hub for significant morphogenetic networks, such as Wnts and Fibroblast Growth Factors. The modeling of these tooth crown changes in mutant mice, via a three-dimensional metamorphosis approach, allowed prediction of how Jagged1-associated mutations in humans could affect the morphology of their teeth. These results shed new light on Notch/Jagged1-mediated signaling as one of the crucial components for dental variations in evolution. [ABSTRACT FROM AUTHOR]

We propose a quantitative approach for categorising mammalian diets based on the taxonomy of food items and parts consumed (the form of food). Our analysis covers 82% of the mammalian species alive today. The diet information comes from different data sources—textbooks, datasets and peer-reviewed literature and includes a transformation of narrative quantitative data into qualitative data. We link a database on nutrient composition of diet items of the quantitative diet data and analyse the distribution of macronutrients of diets across taxonomic groups and map them to the dental morphology of the eaters. The results show associations between dental complexity and the concentrations of some nutrients. Our analysis highlights omnivory as a multi-faceted concept—there are many kinds of omnivores within the dietary space we report. The developed dataset and the proposed approach relating the chemical composition of diets offers a basis for future comparative studies of living and fossil mammals. With this study, we make the accompanying large-scale dietary data publicly available online (https://www.mammalbase.net). [ABSTRACT FROM AUTHOR]

Hystricognath rodents arrived in South America from Africa during the Paleogene. The oldest South American rodents (Caviomorpha) were intensively studied in recent years. One of these assemblages is the caviomorph paleofauna from Santa Rosa, Peru. Their age was originally estimated as ?Eocene. Here, we report new caviomorph fossils from Santa Rosa and review the previously described rodents taking into account new dates and updated caviomorph information. We identified 18 genera and 22 species, including one new genus and species (Vucetichimys pretrilophodoncia gen. et sp. nov.), and two new species (Shapajamys minor sp. nov. and Ucayalimys amahuacensis sp. nov.). All taxa are brachydont, with visible cusps, and thin crests. The Santa Rosa rodents are one of the oldest and the most diverse caviomorph paleofaunas known from low latitudes of South America. Similarities between these caviomorphs and other Paleogene assemblages lead us to propose an early Oligocene age for those rodents from the Yurúa River (Brazil) and a close temporal relationship with the oldest known levels from Contamana. This new biochronological scenario has deep implications in the origin and early evolution of caviomorphs. A middle Eocene? entrance of one or several waves of African rodents arriving in South America is possible. [ABSTRACT FROM AUTHOR]

CT visualization of the mandible and dentition of Hadrocodium wui, a stem mammaliaform from the Lower Jurassic Lower Lufeng Formation of Yunnan, China has revealed new features not accessible by previous microscopic study of the fossil. Its mandible shows a postdentary trough with an overhanging medial ridge and a short Meckel’s sulcus. An incomplete part of the ectotympanic and possibly a remnant of Meckel’s element are preserved in the postdentary trough. Thus, Hadrocodium is similar to other mammaliaforms in retaining a mandibular middle ear, contrary to our earlier interpretation. The mandible exhibits a large postcanine diastema from shedding of anterior premolars without replacement, an age-dependent feature better developed in older adults. Another adult feature is the alignment of the ultimate molar to the coronoid process. This is consistent with age-dependent changes in other mammaliaforms where the last molars of the toothrow shift from medial of the coronoid process in the juvenile, to a position in front of the coronoid process in the adult. The mandible has a short mobile symphysis. The dentition consists of I5, C1 (two-rooted), P3 (including P1 position) and M2 (M2 with confluent roots), and i4, c1 (partially two-rooted), p3, and m2 (m2 with partially confluent roots). The two-rooted upper canines are more derived than other Early Jurassic mammaliaforms from the same fauna, although similar to docodontans. Hadrocodium is unique in that the lower m2 cusp a occludes in the embrasure between upper M1–M2, but the posterior part of m2 shows between-cusp occlusion with upper M2 main cusp A. M2 is half the size of the lower m2, and occludes only with the distal half of m2. The upper postcanines show a steep gradient of posteriorly decreasing tooth size, more so than other mammaliaforms. The CT examination corroborates that there are no unerupted teeth in the upper or lower jaws, and the holotype of H. wui is dentally and osteologically mature and capable of independent feeding.

A new specimen of Lactodens sheni, the only known spalacolestine from the Early Cretaceous Jehol Biota, is reported from the Jiufotang Formation, Liaoning, China. The description focuses on the dental and mandibular morphologies from both the new specimen and the holotype, particularly those that were unknown or poorly known from the holotype when the taxon was established. As revealed primarily by high-resolution computed tomography, morphologies and size gradient of the lower molars and detailed features of the mandibles, such as the masseteric foramen, can be unequivocally described. The dental and mandibular morphologies of Lactodens are compared with those of Origolestes lii, also from the Jehol Biota; these two taxa represent by far the best specimens in Spalacotheriidae and Zhangheotheriidae, respectively, and could be used as the representatives of their own groups in future higher-level phylogenetic analysis of mammals. The two taxa display considerable differences in dental and mandibular features, probably indicating a deeper split of spalacotheriids and zhangheotheriids than previously thought. Absence of the Meckelian groove in Lactodens, contrasting to the distinct one that holds a sizable Meckel’s cartilage in adult Origolestes, suggests an independent evolution of the definitive mammalian middle ear within “symmetrodontans”. The morphological gradient in the tooth row and association of the upper and lower dentitions from the same individual animal are also instructive for interpreting molar variations and evolution in “symmetrodontans” and mammals.

We surveyed molar surface morphology of bats of 281 extant and extinct species in 5 archaic and 19 extant families using scanning microscopy. We note the occurrence of structural features on talonid crests, the cristid obliqua, postcristid, and entocristid, and their absence in upper molars, even of the same species having them on lowers. We term the structures “carnassiform notches” (CN) for their resemblance to similar features on the carnassial teeth of carnivorans. A CN consists of a small cleft in the edge of a talonid shearing crest accompanied by an adjacent “accessory trough” on the basinward side of the notch. The CN occur in bats with tribosphenic molar morphology and insectivorous or insectivorous–omnivorous dietary habits. Of 19 extant families examined, eight include members that possess lower molars with a CN in at least the cristid obliqua: Megadermatidae, Nycteridae, Mystacinidae, Furipteridae, Thyropteridae, Phyllostomidae, Natalidae, and Vespertilionidae (Murininae and Kerivoulinae only). An extinct genus of Hipposideridae, Vaylatsia, shows CN although extant hipposiderids do not. In extinct families for which lower molar fossils are available, notches were not recognized on the talonids, indicating the condition is not plesiomorphic for bats and probably evolved convergently in different lineages. Where present, the CN or troughs are morphologically consistent within a family, and might serve in some cases as characters supporting phylogenetic analyses and clade diagnoses. CN and accessory troughs probably increase the functional efficiency at sectioning chitin by increasing the effective length of a crest while maintaining the same cusp-to-cusp distance and precise occlusal relationships, and by improving the food-capture area of the shearing blade during occlusion. The accessory troughs provide an immediately adjacent fragment-clearance area. The increased sophistication of this food-processing system might be particularly important in species that must quickly acquire, chew, and swallow their food and resume echolocating in flight. The common ancestor of bats probably did not have CN in its molars, and the presence of CN does not signal carnivory in bats.

Dryolestoid mammals are classical members of the Jurassic faunas of Laurasia but mostly absent during the Cretaceous. The reverse is true in Gondwana in general and South America in particular, where meridiolestid dryolestoids are dominant in the Late Cretaceous. We describe here 21 new mammalian specimens from the Upper Cretaceous locality Cerro Tortuga (Allen Formation, Patagonia, Argentina) collected via screenwashing, which we identify as meridiolestid dryolestoids. We recognize a new species of meridiolestid and reassign a previously described specimen to the new taxon. The morphology of these new remains represents a new morphotype in the spectrum of meridiolestid diversity, recording a broadening of trophic adaptations from the ancestral insectivory to the more derived herbivory observed among the later and more derived members of the group. The novel dental morphology helps bridge the anatomy of the plesiomorphic sharp-toothed meridiolestidans with that of the more derived and bunodont mesungulatoids. The new taxon suggests that development of both broad cingulids and complex crown morphology precede the development of the wide compressed roots, bunodonty, and thickened enamel characteristic of derived mesungulatids. Other specimens from the collection are referable to taxa previously known from the same locality. These provide new information about tooth positioning, dental formula, and overall dental morphology. The new material suggests that Groebertherium , previously regarded as a dryolestid taxon, is in fact a likely member of Meridiolestida. • New species of Late Cretaceous dryolestoid mammal identified from Argentina. • Dentition of new species demonstrates dietary diversity among meridiolestidans. • Previously known enigmatic taxa are completed by new specimens. • A precocious and diverse herbivore/omnivore guild is present in the Late Cretaceous of South America. [ABSTRACT FROM AUTHOR]

Dental morphology (DM) is the first introduction of dental graduates towards the identification of tooth; hence it is an important component of the dental curriculum. Traditionally, it is taught by manual carving of wax blocks, but the limitations of this method have been highlighted. There is a need to adopt innovative teaching methodologies to invigorate the concepts of dental anatomy (DA) and reduce the stress in teaching and learning with a proposal in standardization of training methodologies worldwide. Methods: A three-phased project was designed with an aim to collect global data related to teaching dental morphology within the dental curriculum. One dental professional actively involved in university teaching of DM subject was invited from 11 countries. The present study involved compilation of data from phase 1 questionnaire responses, followed by its discussion and analysis, and generation of preliminary report. Results: It is universally acknowledged that acquiring dental morphology knowledge by dentists is a prerequisite before they commence clinical practice. Our data points that no uniformity in DA course modules exists throughout the world and globally the subject requires curriculum redesigning. Conclusions: Consensus should be achieved amongst academicians in DM teaching and learning context. Innovative and standardized DM modules with component of computer-based and remote learning techniques should also be introduced. [ABSTRACT FROM AUTHOR]

Nonenzymatic glycation is a multistep, slow reaction between reducing sugars and free amino groups of long-lived proteins, which affects the structural and mechanical properties of collagen-rich tissues via accumulation of advanced glycation end products (AGEs). Dental collagen is exposed to glycation as part of the natural aging process. However, in case of chronically high blood glucose, the process can be accelerated, resulting in premature stiffening of dentin, leading to tooth fragility. The molecular mechanisms whereby collagen glycation evokes the loss of mechanical stability in teeth are currently unknown. In this study, we used 2-photon and atomic force microscopies to correlate structural and mechanical changes in dental collagen induced by in vitro glycation. Young tooth samples were demineralized and cut longitudinally into 30-µm sections, then artificially glycated in 0.5 M ribose solution for 10 wk. Two-photon microscopy analysis showed that both the autofluorescence and second harmonic–generated (SHG) signal intensities of glycated samples were significantly greater than those of the controls. Regarding the structural alteration of individual collagen fibers, a remarkable increase could be measured in fiber length of ribose-treated sections. Furthermore, nanoindentation of intertubular dentin regions revealed significantly higher stiffness in the ribose-treated samples, which points at a significant accumulation of AGEs. Thus, collagen glycation occurring during sustained exposure to reducing sugars leads to profound structural and mechanical changes in dentin. Besides the numerous oral complications associated with type 2 diabetes, the premature structural and mechanical deterioration of dentin may also play an important role in dental pathology. [ABSTRACT FROM AUTHOR]

The South African Early Jurassic morganucodontan Erythrotherium is considered by some authors to be potentially synonymous with Morganucodon, due to similar tooth morphology. However, despite their similar dental morphology, the occlusal pattern of Erythrotherium parringtoni has been described as embrasure occlusion, close to the mode of Megazostrodon rudnerae, rather than that of Morganucodon. In this study the molars of Erythrotherium were re-examined and the two alternative occlusal hypotheses were tested using the Occlusal Fingerprint Analyser (OFA). Morphological comparison of the molars of Erythrotherium parringtoni to those of Morganucodon watsoni showed similarities in cusp height and shape in lingual/buccal views, but the molars and individual cusps of Erythrotherium parringtoni are considerably narrower linguo-buccally, and more gracile. With cusps a and c close together in Erythrotherium parringtoni, cusp positioning differs from that of Morganucodon watsoni and shows similarities to the pattern in Megazostrodon rudnerae. Also, the upper molars of Erythrotherium parringtoni are aligned in a straight row and lack the angle, relative to the longitudinal axis, between the first and second upper molars that is present in Morganucodon watsoni. This results in embrasure occlusion being the only viable occlusal mode for Erythrotherium parringtoni, which was confirmed by the OFA analysis. A Morganucodon-like occlusion would allow only the main cusps a/A to contact their antagonists and thus major gaps would be present, causing considerable reduction of functionality of the dentition. Based on the morphological evidence and the differing occlusal mode, the perpetuation of Erythrotherium parringtoni as a separate genus is confirmed. [ABSTRACT FROM AUTHOR]

Machairodontinae, including the famous Smilodon and Homotherium, was an iconic Pleistocene carnivore lineage that occupied a critical ecological palaeo‐niche and is thought to have had a profound impact on ice‐age ecosystem structure. Recent ancient molecular studies on Homotherium suggest a wider distribution than that inferred from the fossil record, highlighting a need for additional fieldwork, fossil collection, and research in understudied geographic regions. After the original publication 80 years ago that identified a Pleistocene carnivore fossil as Felis sp. in Taiwan, here we revise its identification and demonstrate the presence of the large machairodontine cat, cf. Homotherium sp., in the Pleistocene of Taiwan, suggesting the eastern‐most occurrence of this lineage in Eurasia. Our results also emphasize the importance of fossil curation and in‐depth research in elucidating regional hidden diversity and lost ecosystem structure for the understanding faunal turnover and the origin of modern biodiversity. [ABSTRACT FROM AUTHOR]

It has been estimated that 25% of monozygotic ("identical") twin pairs exhibit reverse asymmetry (RA) or "mirroring" of minor anatomical features as a result of delayed zygote division. Here, we examine whether identical twin mirroring accounts for patterns of dental asymmetry in a sample of monozygotic and dizygotic ("fraternal") twins. We focus on crown morphology to approach the following question: is there an association between dental RA frequency and twin type suggestive of the presence of mirror image twins in our sample? Data were collected from 208 deciduous and 196 permanent dentitions of participants of the University of Adelaide Twin Study using Arizona State University Dental Anthropology System standards. RA frequencies were compared across morphological complexes (deciduous, permanent), twin types (monozygotic, dizygotic), and traits. Fisher's exact tests were performed to formally evaluate the association between twin type and dental RA. Across the entire dataset, RA rates failed to exceed 8% for any twin type. In monozygotic twins, deciduous mirroring totaled 5.3% of observed cases, while permanent mirroring totaled 7.8% of observed cases. We found no statistically significant association between RA and twin type for any morphological character (p-value range: 0.07-1.00). Our results suggest the timing of monozygotic twin division does not explain the structure of asymmetry for our morphology dataset and that published estimates of identical twin mirroring rates may be inflated or contingent upon phenotype. Instead, rates reported for this sample more closely align with the proposed etiology of this condition., (© 2024 American Association for Anatomy.)

The interest in the development of dental enamel thickness measurement techniques is connected to the importance of metric data in taxonomic assessments and evolutionary research as well as in other directions of dental studies. At the same time, advances in non-destructive imaging techniques and the application of scanning methods, such as micro-focus-computed X-ray tomography, has enabled researchers to study the internal morpho-histological layers of teeth with a greater degree of accuracy and detail. These tendencies have contributed to changes in established views in different areas of dental research, ranging from the interpretation of morphology to metric assessments. In fact, a significant amount of data have been obtained using traditional metric techniques, which now should be critically reassessed using current technologies and methodologies. Hence, we propose new approaches for measuring dental enamel thickness using palaeontological material from the territories of northern Vietnam by means of automated and manually operated techniques. We also discuss method improvements, taking into account their relevance for dental morphology and occlusion. As we have shown, our approaches demonstrate the potential to form closer links between the metric data and dental morphology and provide the possibility for objective and replicable studies on dental enamel thickness through the application of automated techniques. These features are likely to be effective in more profound taxonomic research and for the development of metric and analytical systems. Our technique provides scope for its targeted application in clinical methods, which could help to reveal functional changes in the masticatory system. However, this will likely require improvements in clinically applicable imaging techniques.

Understanding the relationship between form, function and diet in feeding structures is critical to constraining the roles of organisms in their ecosystem and adaptive responses to food resources. Yet, analysis of this relationship in invertebrates has been hampered by a reliance on descriptive and qualitative characterisation of the shapes of feeding structures. This has led to a lack of robust statistical analyses and overreliance on analogy and plausibility, especially for extinct taxa and animals that are hard to observe feeding.Here we test the efficacy of dental topographic metrics in quantification of form in invertebrate mandibles and assess their relationship with diet. Specifically, we analyse the mandibles of 45 species of extant orthopterans. Orthopterans' well‐constrained diets make them an ideal model system for our study.We find that topographic metrics applied to Orthoptera successfully recover the same relationship between dietary intractability and dental tool morphology as they do in mammals, and that combination of individual metrics in multivariate analysis most strongly captures this relationship. Furthermore, multivariate topographic metrics calibrated to the food consumed by mammals accurately predict dietary differences between orthopterans (82% taxa correctly assigned).Our results demonstrate that these metrics can be used in quantitative analysis and comparison of non‐homologous mouthparts to reliably investigate the relationship between diet, form and function of feeding tools across Bilateria. We anticipate that this will facilitate more rigorous ecological analysis of fossil and historical material, providing new methods to investigate adaptive responses and community‐level interactions through time. [ABSTRACT FROM AUTHOR]

An inactivating PHEX gene mutation with the resultant accumulation of several mineralization-inhibiting proteins (e.g., FGF23) causes skeletal and dental morbidity in X-linked hypophosphatemia (XLH). This prospective case-control study explored the effect of burosumab, an anti-FGF23 antibody, on dental health of children with XLH. Ten children (age 4.3-15 years) with XLH underwent burosumab treatment per protocol. Assessment of their dental status at treatment initiation and after 1 and 3 years of treatment included clinical, laboratory and radiographic evaluation of rickets and dentition. Orthopantomographic examinations of ten healthy sex- and age-matched controls were selected for comparison. Coronal and pulp dimensions of a selected permanent mandibular molar were measured with Planmeca Romexis® software. One year of treatment led to improvement of height z-score (p=0.019) and healing of the rickets (p

Voles from the Genus Microtus are rodents with a subterranean lifestyle. Central Italy is populated by two species of the Genus, the North-Western Microtus savii and the South-Eastern endemic Microtus brachycercus. Although morphometric features able to help distinguish M. savii from M. brachycercus are lacking, a peculiar morphology of the anterior end of the first lower molar is typical, but not exclusive, of M. brachycercus. Since some skulls with a compatible dental morphology were collected from Long-eared owl pellets in Umbria (Central Italy), a genetic assessment was deemed necessary to verify the possible presence of M. brachycercus outside of its known distribution range. Hemimandibles were isolated and used for both genetic and morphometric dental analyses. Despite the fact that this could suggest the presence of a M. brachycercus population, genetic analyses confirmed the species attribution to the M. savii complex, showing peculiar genetic polymorphisms that can either be due to the wide sampling area, represented by the owls’ hunting grounds, or to the recent evolutive history of the analysed population. This study, once again, underlines the importance of integrative taxonomy, suggesting the key role of predators as field-assistants to minimize the impact of sampling campaign on natural populations.

Taxonomic decisions made by palaeontologists are often based on a few morphological features preserved in the fossil material. This practice may sometimes lead to the description of new species based on single specimens, which are, in fact, extreme or aberrant morphological variants of known taxa. Ancient DNA (aDNA) analysis of the Late Pleistocene specimens from the archaeological site Petits Guinards (Creuzier-la-Vieux, Allier, France), described as a new vole Microtus (Sumeriomys) bifrons, did not confirm the species distinctness of the studied population. The genetically examined specimens belonged to Stenocranius anglicus and/or Microtus arvalis, the dominant species at the site. Our findings show that it is risky to describe new fossil taxa on the basis of phenotypic outliers or morphologically aberrant, rare specimens that do not fall within the previously known population variability. We also highlight the importance of ancient DNA in resolving taxonomic and nomenclature problems and classifying fossil mammals of the Late Pleistocene age.

Forensic anthropologists operate within a medico-legal context, performing analyses to estimate a biological profile (ancestry, age, sex, stature) and make observations on trauma, pathological conditions, taphonomy, and other anomalies evident in skeletal remains. These findings are reported to the appropriate requesting agency to narrow down the possible identity of the unknown individual and to understand the death event. Boundaries of identity and the terminology used to describe and explain identity are dynamic and intersectional. Ancestry estimation is important because there is a bridge between ancestral categories and socio-cultural labels. Yet, a lack of agreement between ancestry estimates and social identifiers exists for certain groups. To better understand why this disagreement exists, a three-component concept (bio-origin identity, public ancestral-racial identity, and self ancestral-racial identity) modeled after sociological frameworks is employed. This article explores the identity of a single individual within the study sample using the three-component concept. Results highlight that discordance exists between the identity approximated by ancestry estimation and the application of this identity to the socio-cultural context. Understanding the importance of the intersectional nature of the terminology used in instances of forensic identification is imperative so as to not hinder identifications and marginalize groups. [ABSTRACT FROM AUTHOR]

Bats are one of the most abundant and important mammals in ecosystems. However, their fossil record is scarce and fragile, making them difficult to find. Accordingly, there is no record of this group in the volcanic islands of the mid-Atlantic Ocean apart from the Canary Islands. This paper studies the first bat fossil record of the Canary Islands (Spain). The material studied is found within two Quaternary lava tubes, Cueva de los Verdes on Lanzarote and Cueva Roja on the island of El Hierro. The dental and humeral morphology and biometry are analysed and compared with current specimens. Among our results we highlight the first fossil data of two species endemic to the islands of the mid-Atlantic Ocean, Plecotus teneriffae and Pipistrellus maderensis, the former from the Canary Islands and the latter from the Azores, Madeira and the Canary Islands. We also confirm the presence of Pipistrellus kuhlii in the fossil record of the island of Lanzarote. No differences are observed between the dental morphology of the current and the fossil populations of P. maderensis and Pl. teneriffae. In the case of P. kuhlii, the populations of the Canary Islands and the Iberian Peninsula show differences in the paraconule with respect to the populations from central Europe. Palaeoecological studies of these taxa suggest that these islands presented a similar habitat when the sites were formed to the present-day habitat. [ABSTRACT FROM AUTHOR]

According to the multifactorial pathological model, dental morphology has been associated as one of the etiological factors of caries by favoring the accumulation of food remains and biofilm retention. One of the most frequent of non-metric dental traits of the Colombian population is the P point of the protostylid, which is constituted in a fossa that is expressed in the bucomesial development groove of the lower molars, a region that follows the occlusal surface as one of sites where carious lesions develop more frequently. However, the lack of knowledge of this morphological feature by most dentists makes the morphological system of the protostylid misdiagnosed, which in many cases leads to the overtreatment of this pit with invasive therapies, which could be avoided with a knowledge adequate dental morphology and with a preventive management or non-invasive techniques. Therefore, the aim of this review of the subject is to reconcile the expression of the P point of the protostylid and to make an approximation to the clinical implications of the same and the conservative diagnostic and therapeutic possibilities offered by dentistry to control the accumulation of food rests and retention of dental biofilm.

Taurodontism, a known morpho-anatomic variation in the shape of teeth, has already attracted substantial attention. The aim of this study is to contribute to this by discussing its direct impact on the dental practitioner via an evaluation of the prevalence of taurodontism in molars in Ashkelon, Israel. This retrospective study analyzed panoramic radiographs of 624 patients (330 males, 294 females), aged of 9–29 years—2849; first and second permanent molars were screened. Objective measurements and variables were used and analyzed using statistical SPSS version 27 (IBM, Chicago, IL, USA). Taurodontism was observed in 33.6% of the patients and was more prevalent among females (53% vs. 47%) and in maxillary molars compared to mandibular molars (57% vs. 43%). The overall prevalence of hypotaurodontism, mesotaurodontism, and hypertaurodontism was 10.8%, 0.5%, and 0.2%, respectively. No statistical difference between right and left sides was discovered, however, taurodont teeth in the upper left side exhibited the highest frequency, while the lower left side had the least. The highest occurrence of hypotaurodontism was on the upper right second molar followed by upper left first and second molars. The clinical challenge posed in endodontic, orthodontic, and restorative dentistry is discussed, and suitable alternative approaches are proposed for dental practitioners. [ABSTRACT FROM AUTHOR]

We surveyed molar surface morphology of bats of 281 extant and extinct species in 5 archaic and 19 extant families using scanning microscopy. We note the occurrence of structural features on talonid crests, the cristid obliqua, postcristid, and entocristid, and their absence in upper molars, even of the same species having them on lowers. We term the structures "carnassiform notches" (CN) for their resemblance to similar features on the carnassial teeth of carnivorans. A CN consists of a small cleft in the edge of a talonid shearing crest accompanied by an adjacent "accessory trough" on the basinward side of the notch. The CN occur in bats with tribosphenic molar morphology and insectivorous or insectivorous-omnivorous dietary habits. Of 19 extant families examined, eight include members that possess lower molars with a CN in at least the cristid obliqua: Megadermatidae, Nycteridae, Mystacinidae, Furipteridae, Thyropteridae, Phyllostomidae, Natalidae, and Vespertilionidae (Murininae and Kerivoulinae only). An extinct genus of Hipposideridae, Vaylatsia, shows CN although extant hipposiderids do not. In extinct families for which lower molar fossils are available, notches were not recognized on the talonids, indicating the condition is not plesiomorphic for bats and probably evolved convergently in different lineages. Where present, the CN or troughs are morphologically consistent within a family, and might serve in some cases as characters supporting phylogenetic analyses and clade diagnoses. CN and accessory troughs probably increase the functional efficiency at sectioning chitin by increasing the effective length of a crest while maintaining the same cusp-to-cusp distance and precise occlusal relationships, and by improving the food-capture area of the shearing blade during occlusion. The accessory troughs provide an immediately adjacent fragment-clearance area. The increased sophistication of this food-processing system might be particularly important in species that must quickly acquire, chew, and swallow their food and resume echolocating in flight. The common ancestor of bats probably did not have CN in its molars, and the presence of CN does not signal carnivory in bats. [ABSTRACT FROM AUTHOR]

Recent progress in imaging and image processing techniques has provided for improvements in odontological research in a variety of aspects. Thus, the presented method has been developed precisely in order to assess metrically 3D reconstructions of teeth. Rapidly and accurately obtained data of a wide range and appropriate density are sufficient enough for morphometric studies rather than tooth size assessments which are inherent to conventional techniques. The main contributions providing for holistic and objective morphometric analysis of teeth are the following: (1) interpretation of basic dental morphological features; (2) automated of orientational coordinate system setup based on tooth surface analysis; (3) new tooth morphometric parameters which could not be obtained through application of conventional odontometric techniques; (4) methodological novelty for automated odontomorphometric analysis pipeline. Application of tomographic imaging, which has been used for obtaining 3D models, expands the proposed method potential further through providing detailed and comprehensive reconstructions of teeth. The current study was conducted on unique material from the archaeological site of Sunghir related to the Upper Palaeolithic period. Metric assessments of external and internal morphological layers of teeth were performed in common orientation and sectioning. The proposed technique allowed more profound analysis of Sunghirian teeth which date back to the times of modern human morphology formation. [ABSTRACT FROM AUTHOR]