Dental anomalies in the gray foxUrocyon cinereoargenteus and the red foxVulpes vulpes

We examined dental anomalies, including oligodonty, polydonty, connation, rotation, and misalignment in 510 gray foxes and 150 red foxes from southern Illinois (USA). Dental anomalies were significantly more common (x ² = 11.5, df = 1,p < 0.001) in gray foxes (n = 177; 34.7% of sample) than red foxes (n = 25; 16.6% of sample), and more common in male than female gray foxes (x ² = 3.88, df = 1,p < 0.05). Polydonty was very uncommon, as expected for species in which the normal dental complement is close to the primitive eutherian number. In both species, the most prevalent anomaly was loss of the last lower molar. Loss of the upper or lower first premolar was also common. Thus, oligodonty almost always involved the smaller anterior (P¹ and P₁) or posterior (M₃) teeth of the dental arcade. Conversely, the large carnassial teeth, with complex occlusal patterns and shearing surfaces, appeared to be highly conserved with only three anomalous individuals (0.4%) among all specimens.     

Dental anomalies in wild and domestic<Emphasis Type="Italic">Sus scrofa</Emphasis> in Illinois

The cleaned skulls of 39 wild and 30 domestic pigs from southern Illinois (USA) were assessed for dental anomalies including polydonty, oligodonty, misalignment, and rotation. Dental anomalies occurred in 16 wild and 15 domestic pigs. Oligodonty (either bilateral or unilateral) was the most common anomaly, occurring in 9 wild (23.1% of the sample) and 15 (50%) domestic pigs. In 22 of the 24 individuals exhibiting oligodonty, this anomaly involved the lower first premolar (P₁). Given the placement of P₁, oligodonty may reflect a trend toward reduction of the dental arcade from the primitive eutherian number. Domesticated species are reported to have more anomalies than wild counterparts because of inbreeding. We found no difference in the number of dental anomalies between domestic and wild pigs.     

Development of the orangutan permanent dentition: Assessing patterns and variation in tooth development

This study examines dental formation and alveolar emergence in a large cross-sectional sample composed primarily of wild-reared orangutans (N = 89) in order to provide information on the development of the permanent dentition in this hominoid and to address questions of variation in individual tooth formation, between teeth and between individuals. All specimens have been radiographed in lateral aspect and stages of crown and root formation recorded for all teeth. The ranges of crown and root formation of I¹₁, C¹₁, P⁴₄, and M³₃ have been calculated relative to the stage of M₁¹ development within a specific tooth quadrant. Then, for each specimen, BMDP scatterplot and nonparametric statistics have been used to graph changes in stages of these teeth relative to M¹₁ stages and to examine relationships between pairs of upper and lower dental counterparts and between teeth of each jaw. Results indicate 1) high correlations between upper and lower tooth pairs and between many of the permanent teeth within individuals, 2) a relatively large range of variability in individual tooth development (multistage ranges relative to M¹₁), 3) greater variation in root development at emergence than earlier reports, and 4) evidence of variability within the sequence emergence pattern of the orangutan. © 1996 Wiley-Liss, Inc.     

Microevolutionary trends in the dentition of the Red fox (Vulpes vulpes)

Microevolutionary trends in dental traits were studied in a Polish population of the Red fox, Vulpes vulpes (Linnaeus, 1758). Changes in qualitative and quantitative traits over a 70‐year interval were analysed in 1453 museum specimens collected between 1927 and 1996. Over that period, there were qualitative trends towards increasing complication of occlusal crown surface in posterior premolars (i.e. P⁴, P₃, P₄) and I³. Other cheek teeth did not undergo directional change. Changes in trait correlations were assessed using samples from the 1960s and 1990s. The correlations between C¹–C₁ and M¹–M² increased, while correlation values in the incisor region (I₁–I₂, I¹–I₁, I¹–I₂, I³–I₂), carnassial region (P₄–M₁, P⁴–M₁ and M₁–M₁) and in P²–P₁ decreased. These changes may be related to increasing dietary opportunism of the Red fox during the 20th century.     

Dental anomalies in the Japanese mole <Emphasis Type="Italic">Mogera wogura</Emphasis> from northeast China and the Primorsky region of Russia

Dental anomalies in the Japanese mole, Mogera wogura Temminck, 1842, from northeast China and the Primorsky region of Russia were examined based on 241 specimens. The most frequent dental anomaly was oligodonty, i.e., missing P² (18 cases) or P₃ (one case). Supernumerary teeth were observed in three cases, two of which were characterized by abnormal shapes. Morphological abnormalities in teeth (six cases) and an asymmetrically curved rostrum (one case) were also observed. Dental anomalies were found at higher frequencies in populations near the northern range limit of the species. This was not caused by size effects. We suggest that the high incidence of dental anomalies was the result of genetic drift, which increases in marginal populations. Considering the nature of subterranean mammals, our results suggest that the high frequency of dental anomalies in a marginal population could have initiated the evolution of dental formulae if parapatric or peripatric speciation occurs in such populations.     

Population analysis of dental anomalies of ottersLutra lutra from eastern Germany

A sample of 1037 skulls of ottersLutra lutra (Linnaeus, 1758) from eastern Germany was analysed for inherent dental abnormalities. Deviations from the normal dental pattern were found in 107 individuals. A total of 150 cases were classified in 5 categories of abnormality. In considering variations from the normal number of teeth, supernumerary (polydonty, 1.7%) was more frequent than missing teeth (oligodonty, 0.9%). In most cases, numerical variations were not connected with phylogenetic background. The most frequent variations were displacement of teeth in the tooth row (6.0%) and deviations of the normal shape of teeth (3.3%). Variations of the local position of teeth occurred in 2.6% of cases. None of these deviations showed significant sex-dependent differences. Furthermore, no regional differences in the frequencies of these anomalies were noticed. Another 459 otters (822 cases) had accessory roots at P2, P3, or P4. These characters were considered as non-metrical traits and used to study epigenetic regional differentiation. The Mean Measure of Divergence segregated the Baltic coast from almost all other regions. Preliminary results of analysis of Fluctuating Asymmetry are presented, using these traits to demonstrate the utility of dental deviations for estimating influences on developmental stability. Generally, it can be stated that the dentition of otters is very stable.     

Metrical dental analysis on golden monkey (Rhinopithecus roxellana)

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

Traumatic injury to the incisive bones and maxillary dentition in a male gray wolf (Canis lupus L.) from Slovakia

The paper presents the skull of a male gray wolf shot in the region of Snina, eastern Slovakia. Age at death of the wolf was estimated at 6 years. The skull was characterized by the almost-complete absence of the alveolar processes of the incisive bones and multiple dental abnormalities that were attributed to a severe trauma. All maxillary incisors and both maxillary first premolars were missing. In addition, both maxillary canines were fractured with only tooth fragments being left. The pulp exposure associated with the crown fractures of the maxillary canines had caused pulp necrosis and periapical lesions, as evidenced on radiographs. The right P², P³, and P⁴ were fractured, with only the remaining tooth structure of the second and third premolars being left. In the right P⁴ and the left M¹, periapical bone resorption was diagnosed radiologically. In the mandibular dentition, the right I₂ and left P₁ had been lost in life. The mandibular canines exhibited distinct wear facets that were caused by contact with the maxillary third incisors, which were subsequently lost. The fact that all fractured teeth showed signs of wear indicates that the trauma had occurred some time before the wolf was shot.     

Dental anomaly in a fossil squalodont dolphin from New Zealand,and the evolution of polydonty in whales

Abstract

A fragment of mandible of an indeterminate squalodontid dolphin (Upper Oligocene or lowermost Miocene, New Zealand) has 2 anomalous single-rooted teeth intercalated between typically squalodontid anterior cheek-teeth. The anomalous teeth are considered to be truly supernumerary, and not homologous with any erupted teeth in phylogenetically earlier Cetacea. This type of anomaly appears not to have been reported previously for any fossil cetacean. Polydonty, a characteristic of extant odontocetes, was probably attained initially in primitive odontocetes by intercalation of permanent and deciduous teeth, and later was elaborated by the addition of supernumerary teeth. The present specimen represents a morphological (but not phylogenetic) stage between odontocetes with limited and advanced polydonty. Some fossil mysticetes and embryonic extant mysticetes are also polydont, but mysticete polydonty and that of odontocetes have probably evolved convergently.     

New dental remains of Anoiapithecus and the first appearance datum of hominoids in the Iberian Peninsula

New dental remains of the fossil great ape Anoiapithecus brevirostris are described from the Middle Miocene local stratigraphic series of Abocador de Can Mata (ACM) in els Hostalets de Pierola (Vallès-Penedès Basin, NE Iberian Peninsula). These specimens correspond to maxillary fragments with upper teeth from two female individuals from two different localities: left P³–M¹ (IPS41712) from ACM/C3-Aj (type locality; 11.9 Ma [millions of years ago]); and right M¹–M² and left P⁴–M² (IPS35027) from ACM/C1-E* (12.3–12.2 Ma). Relative enamel thickness is also computed in the latter individual and re-evaluated in other Middle Miocene hominoids from ACM, in order to better assess their taxonomic affinities. With regard to maxillary sinus development, occlusal morphology, molar proportions and enamel thickness, the new specimens show greater resemblances with the (male) holotype specimen of A. brevirostris. They differ from Pierolapithecus catalaunicus in displaying less inflated crests, a more lingually-located hypocone, and relatively lower-crowned molars; from Dryopithecus fontani, in the relatively thicker enamel and lower-crowned molars; from Hispanopithecus spp., in the more inflated crown bases, less peripheral cusps and more restricted maxillary sinus; and from Hispanopithecus laietanus also in the thicker crests, more restricted occlusal foveae, and relatively lower-crowned molars. The new specimens of A. brevirostris show some slight differences compared with the holotype of this species: smaller size (presumably due to sexual size dimorphism), and less distally-tapering M² occlusal contour (which is highly variable in both extant and extinct hominoids). The reported remains provide valuable new evidence on dental intraspecific variation and sexual dimorphism in Anoiapithecus. From a taxonomic viewpoint, they support the distinction of this taxon from both Dryopithecus and Pierolapithecus. From a chronostratigraphic perspective, IPS35027 from ACM/C1-E* enlarges the known temporal distribution of Anoiapithecus, further representing the oldest record (first appearance datum) of hominoids in the Iberian Peninsula.     

Mandibular molar root morphology in Neanderthals and Late Pleistocene and recent Homo sapiens

Neanderthals have a distinctive suite of dental features, including large anterior crown and root dimensions and molars with enlarged pulp cavities. Yet, there is little known about variation in molar root morphology in Neanderthals and other recent and fossil members of Homo. Here, we provide the first comprehensive metric analysis of permanent mandibular molar root morphology in Middle and Late Pleistocene Homo neanderthalensis, and Late Pleistocene (Aterian) and recent Homo sapiens. We specifically address the question of whether root form can be used to distinguish between these groups and assess whether any variation in root form can be related to differences in tooth function. We apply a microtomographic imaging approach to visualise and quantify the external and internal dental morphologies of both isolated molars and molars embedded in the mandible (n = 127). Univariate and multivariate analyses reveal both similarities (root length and pulp volume) and differences (occurrence of pyramidal roots and dental tissue volume proportion) in molar root morphology among penecontemporaneous Neanderthals and Aterian H. sapiens. In contrast, the molars of recent H. sapiens are markedly smaller than both Pleistocene H. sapiens and Neanderthals, but share with the former the dentine volume reduction and a smaller root-to-crown volume compared with Neanderthals. Furthermore, we found the first molar to have the largest average root surface area in recent H. sapiens and Neanderthals, although in the latter the difference between M₁ and M₂ is small. In contrast, Aterian H. sapiens root surface areas peak at M₂. Since root surface area is linked to masticatory function, this suggests a distinct occlusal loading regime in Neanderthals compared with both recent and Pleistocene H. sapiens.     

Dental characters of the Quaternary tapirs in China, their significance in classification and phylogenetic assessment

Most of the Quaternary tapir fossils from China are isolated teeth. The purpose of this paper is to identify them and to extract systematic and evolutionary information from them. Based on morphology and W/L ratio, isolated teeth can be identified successfully. On the whole, the identification of P¹, M³ and P₂ is believed to be reliable, while it is difficult to distinguish P₃ from P₄, M₁ from M₂ etc. Concerning the variations of the teeth, P¹ is the most variable one in dimension. In the Quaternary tapirs in China, some dental characters can be used as reliable indicators to evaluate their evolutionary levels. The degree of the atrophy of the upper canine relative to the caniniform I³ is reflected in the C/I³ diameter ratio, which is decreasing during evolution. P¹ changes considerably in outline and strength of the hypocone. Some forms are without hypocone, such as Tapirus sanyuanensis, some have a very faint hypocone, such as Tapirus indicus; although most of them show a developed hypocone. For other cheek teeth, the W/L ratio is decreasing through geologic time. Two lineages can be tentatively proposed: one is the Tapirus peii-Tapirus sinensis-Megatapirus augustus progression; the other is the T. sanyuanensis-T. indicus lineage. T. sanyuanensis and T. peii stand on the base, and it is very probable that the latter is more primitive.     

«Relative growth» from the dentino-enamel junction in primate maxillary molars

The dentino-enamel junction is critical throughout growth to mature crown configurations, being the interface between the papilla and the dental cap. Enamel deposition occurs relatively late and often causes changes from the pattern residing in the dentino-enamel junction. Primate teeth (mostly M¹) have been stripped of enamel after measurement and mapping of the original crown. Relative growth, a variant of static adult (allomorphic) allometries, is assessed by displacement of enamel basal crown component landmarks from dentine homologues relative to tooth size. The hypothesis that differential enamel growth reflects evolutionary history is supported by the positive allometry and shape differences in enamel versus dentine landmarks among phyletically enlarged and dentally-reduced primates.     

Occlusal and morphogenetic field evolution in the dentition of European Nyctitheriidae (Euarchonta,Mammalia)

Abstract

The nyctithere genera Saturninia, Cryptotopos and members of the subfamily Amphidozotheriinae are well-represented by dental remains in the European later Eocene. Their molar occlusal relations are described in detail, demonstrating a diversity of adaptations to insectivory, including dilambdodonty, minor trends in zalambdodonty, development of a large talon shelf in upper first and second molars and a step in the trigon-trigonid shearing surface that provides an extra facet in buccal phase. Minor lingual phase wear is recognized for the first time in the family, but only in relatively worn teeth. Nyctithere molars differ from those of most insectivorous mammals today in having well-developed paraconules and metaconules on upper molars, which in most cases lack a marked bucco-lingual tilt, associated with a more transverse jaw action. Amphidozotherium, however, shows tilting and a basally shifted M¹ hypocone associated with M₁ talonid exodaenodonty and a minor trend in zalambdodonty. Nyctitheres primitively have three deeply notched lobate lower incisors and a large but procumbent premolariform lower canine. Amphidozotheriines have modified their I₃ into a premolariform tooth, by shifting the premolarization field mesially. Amphidozotherium has also shifted this field distally, reducing P_2–3 in size and their roots from two to one.     

The Early Aurignacian human remains from La Quina-Aval (France)

There is a dearth of diagnostic human remains securely associated with the Early Aurignacian of western Europe, despite the presence of similarly aged early modern human remains from further east. One small and fragmentary sample of such remains consists of the two partial immature mandibles plus teeth from the Early Aurignacian of La Quina-Aval, Charente, France. The La Quina-Aval 4 mandible exhibits a prominent anterior symphyseal tuber symphyseos on a vertical symphysis and a narrow anterior dental arcade, both features of early modern humans. The dental remains from La Quina-Aval 1 to 4 (a dm₁, 2 dm₂, a P⁴ and a P₄) are unexceptional in size and present occlusal configurations that combine early modern human features with a few retained ancestral ones. Securely dated to ∼33 ka ¹⁴C BP (∼38 ka cal BP), these remains serve to confirm the association of early modern humans with the Early Aurignacian in western Europe.     

L’orang-outan fossile de Hoà Binh (Viêt-nam) : poids corporel et hypothèse locomotrice

The orang-utan of Hoà Binh (Vietnam): body weight and locomotor hypothesis. The discovery of the first complete skeleton of an adult orang-utan (Pongo pygmaeus), probably a female, in the Hoà Binh province, Vietnam, brings original data about the evolution of these primates. We have predicted the body weight of this orang-utan by using two parameters : dental (crown area of cheek teeth) and skeletal (lengths of femur, radius and tibia). The dental dimensions give plausible predicted estimates of body weights that range between 70.9–112.4 kg for M¹ (with a mean of 89.3 kg) and 67.9–98.1 kg for M₁ (with a mean of 81.6 kg). From the observations of Sugardjito and van Hoof [21] on modern orang-utans, heavy body weights have some influence both on the employment of certain types of locomotion and on travelling heights. To cite this article : A.-M. Bacon, V.T. Long, C. R. Palevol 2 (2003).     

Dental topography and diets of four old world monkey species

Dental topographic analysis allows comparisons of variably worn teeth within and between species to infer relationships between dental form and diet in living primates, with implications for reconstructing feeding adaptations of fossil forms. Although analyses to date have been limited mainly to the M₂s of a few primate taxa, these suggest that dental topographic analysis holds considerable promise. Still, larger samples including a greater range of species and different tooth types are needed to determine the potential of this approach. Here we examine dental topography of molar teeth of Cercocebus torquatus (n=48), Cercopithecus campbelli (n=50), Colobus polykomos (n=50), and Procolobus badius (n=50). This is the first such study of large samples of Old World monkeys, and the first to include analyses of both M₁s and M₂s. Average slope, relief, and surface angularity were computed and compared among tooth types, wear stages, and species. Results suggest that (1) data for M₁s and M₂s cannot be compared directly; (2) slope and relief decline with wear on M₂s of all taxa, and M₁s of the colobines, whereas angularity does not generally change except in the most worn specimens; and (3) folivorous colobines tend to have more sloping surfaces and more relief than do frugivorous cercopithecines, though angularity does not clearly separate taxa by diet. Am. J. Primatol. 71:466–477, 2009. © 2009 Wiley‐Liss, Inc.     

Growth and development of seminal and crown root systems in N-limited barley,and their contributions to nitrate acquisition during vegetative and generative growth

Barley (Hordeum vulgare L., cvs Golf and Laevigatum) was grown under nitrogen limitation, controlled by the relative rate of nitrate-N addition (RA), in solution culture. The seminal and crown root systems were kept apart, but in contact with the same nutrient solution throughout culturing. Growth, nitrate uptake, and in vitro nitrate reductase (NR) activity in the different root parts were studied at plant ages from 40 (late vegetative stage) to 110 (mid grain-filling) days. The RA was during this time interval stepwise decreased from 0.08 day^–1 to 0.005 day^–1. The ratio between seminal root dry weight and total plant dry weight decreased drastically during post-anthesis growth, whereas the contribution by crown roots remained unchanged. Tissue nitrogen concentrations in seminal roots did not change with time, but decreased in crown roots after day 80. The NR activity decreased with age in both seminal and crown roots. The V_max for net nitrate uptake decreased throughout the experiment in the seminal root system, but not in the crown root system. The kinetic properties (V_max and K_M) were used to calculate the nitrate concentration required to maintain a relative rate of nitrate-N uptake that equals the relative addition rate. These concentrations (2 to 5 mmol m^–3) were found to closely match actually measured nitrate concentrations in the nutrient solution (1 to 6 mmol m^–3). From uptake kinetics, it was deduced that the contribution by seminal roots to total nitrate uptake at these concentrations decreased from more than 50% in vegetative plants, to about 20% just after main shoot anthesis, and to less than 5% during grain-filling. ei]Section editor: H Lambers     

Early Cretaceous mammals of Western Siberia: 2. Tegotheriidae

New specimens of the tegotheriid docodont Sibirotherium rossicum Maschenko et al., 2003, including a maxillary fragment with two posterior teeth, an isolated upper molar, and mandibular fragments with teeth from the Early Cretaceous Shestakovo locality are described. The dental formula of Sibirotherium is I_{1 + ?}C1P₆M_6?. The upper molars of Sibirotherium, with two main labial and three lingual cusps, are convergently similar to the molars of tribosphenic mammals. In the dentary, the symphysis is short and Meckel’s groove is reduced. Sibirotherium is similar in the structure of lower teeth to Tegotherium from the Upper Jurassic of Mongolia; it is the latest known representative of Docodonta.