Canine size, shape, and bending strength in primates and carnivores

Anthropoid primates are well known for their highly sexually dimorphic canine teeth, with males possessing canines that are up to 400% taller than those of females. Primate canine dimorphism has been extensively documented, with a consensus that large male primate canines serve as weapons for intrasexual competition, and some evidence that large female canines in some species may likewise function as weapons. However, apart from speculation that very tall male canines may be relatively weak and that seed predators have strong canines, the functional significance of primate canine shape has not been explored. Because carnivore canine shape and size are associated with killing style, this group provides a useful comparative baseline for primates. We evaluate primate maxillary canine tooth size, shape and relative bending strength against body size, skull size, and behavioral and demographic measures of male competition and sexual selection, and compare them to those of carnivores. We demonstrate that, relative to skull length and body mass, primate male canines are on average as large as or larger than those of similar sized carnivores. The range of primate female canine sizes embraces that of carnivores. Male and female primate canines are generally as strong as or stronger than those of carnivores. Although we find that seed-eating primates have relatively strong canines, we find no clear relationship between male primate canine strength and demographic or behavioral estimates of male competition or sexual selection, in spite of a strong relationship between these measures and canine crown height. This suggests either that most primate canines are selected to be very strong regardless of variation in behavior, or that primate canine shape is inherently strong enough to accommodate changes in crown height without compromising canine function.     

Characterization of the Nonstructural Proteins of the Bocavirus Minute Virus of Canines

We present a detailed characterization of a single-cycle infection of the bocavirus minute virus of canines (MVC) in canine WRD cells. This has allowed identification of an additional smaller NS protein that derives from an mRNA spliced within the NS gene that had not been previously reported. In addition, we have identified a role for the viral NP1 protein during infection. NP1 is required for read-through of the MVC internal polyadenylation site and, thus, access of the capsid gene by MVC mRNAs. Although the mechanism of NP1''s action has not yet been fully elucidated, it represents the first parvovirus protein to be implicated directly in viral RNA processing.     

Sexual dimorphism of the dental tissues in human permanent mandibular canines and third premolars

Methods of measuring tissue area from images of longitudinal thin tooth sections have been used to assess sexual dimorphism in the permanent dentition. The aim of this study was to demonstrate the extent of sexual dimorphism within the coronal tissue proportions of permanent mandibular canines and premolars, using area measurements of the enamel and dentine-pulp core. The sample consisted of embedded "half-tooth" sections from 45 individuals, all of known age-at-death and sex, collected from the St. Thomas' Anglican Church historic (1821-1874) cemetery site in Belleville, ON, Canada. The relative dentine-pulp area of the third premolars and canines displayed high levels of sexual dimorphism, as well as statistically significant mean differences between the sexes. The male canines and premolars have significantly more dentine than their female counterparts, as well as relatively more dentine with respect to overall crown size. The female canines and premolars have significantly more enamel relative to overall crown area than those of the males. These results suggest that relative area measures of crown tissues are more predictable measures of sexual dimorphism than absolute measures, and tissue proportions may remain constant despite intrasex variation in overall tooth crown size.     

Genomic features of the human bocaviruses

The human bocavirus (HBoV) was initially discovered in 2005 as the second pathogenic member of the parvovirus family, next to the human parvovirus B19. HBoV has since been shown to be extremely common worldwide and to cause a systemic infection in small children often resulting in respiratory disease. Three more, presumably enteric, human bocaviruses (HBoV2-4) have been identified in stool samples. Parvoviruses are assumed to replicate via their genomic terminal hairpin-like structures in a so-called 'rolling-hairpin model'. These terminal sequences have recently been partially identified in head-to-tail HBoV-PCR amplicons from clinical samples, and are most likely hybrid relics of HBoV's predecessors, namely bovine parvovirus 1 on the left-hand side and minute virus of canines on the right, shown for the first time in this article. Thereby, the replication model postulated for HBoV remains questionable as the occurrence of head-to-tail sequences is not a typical feature of the rolling-hairpin replication model. However, such episomes can also be persistent storage forms of the genome.     

Canine root development and morphology inMacaca nemestrina

Recently,Yoshikawa andDeguchi (1992) reported an unusually high frequency (40%) of two-rooted maxillary canines inMacaca fuscata females and a complete absence of this trait in males. In the present study, canine root development and morphology was examined using cephalographs taken on 50 male and 50 femaleMacaca nemestrina, and 20 male and 20 femalePapio cynocephalus for comparison with the Japanese macaque. The results showed no double-rooted canines present in either species in the upper or lower canines. This supports the general rule that, among primates, canines possess a single-root. It was further suggested that the two-rooted canines inM. fuscata may be the result of the founder effect, i.e. that the genes for this trait may have been carried by the initial populations when they arrived on the islands sometime during the middle to late Pleistocene.     

Canine Evolution in Sabretoothed Carnivores: Natural Selection or Sexual Selection?

The remarkable elongated upper canines of extinct sabretoothed carnivorous mammals have been the subject of considerable speculation on their adaptive function, but the absence of living analogues prevents any direct inference about their evolution. We analysed scaling relationships of the upper canines of 20 sabretoothed feliform carnivores (Nimravidae, Barbourofelidae, Machairodontinae), representing both dirk-toothed and scimitar-toothed sabretooth ecomorphs, and 33 non-sabretoothed felids in relation to body size in order to characterize and identify the evolutionary processes driving their development, using the scaling relationships of carnassial teeth in both groups as a control. Carnassials display isometric allometry in both sabretooths and non-sabretooths, supporting their close relationship with meat-slicing, whereas the upper canines of both groups display positive allometry with body size. Whereas there is no statistical difference in allometry of upper canine height between dirk-toothed and scimitar-toothed sabretooth ecomorphs, the significantly stronger positive allometry of upper canine height shown by sabretooths as a whole compared to non-sabretooths reveals that different processes drove canine evolution in these groups. Although sabretoothed canines must still have been effective for prey capture and processing by hypercarnivorous predators, canine morphology in these extinct carnivores was likely to have been driven to a greater extent by sexual selection than in non-sabretooths. Scaling relationships therefore indicate the probable importance of sexual selection in the evolution of the hypertrophied sabretooth anterior dentition.     

Feeding ecology and morphology of the upper canines in bears (carnivora: Ursidae)

The morphology and mechanical strength of the upper canines in all eight extant species of ursids is analyzed, and the findings are discussed in relation to feeding ecology. Ursids have proportionally smaller canines than other large carnivores with a specialized feeding ecology, such as large felids, and the upper canine morphology is both canid‐like and felid‐like. The giant panda is the most divergent species, and its short, blunt, and cone‐like canines appear well adapted for tearing into bamboo. The almost equally herbivorous spectacled bear has a less derived canine morphology. The large canines of the sun bear are divergent from other ursine ursids, and may be an adaptation for tearing open tree trunks in search of insects. Discriminant Analysis is successful in separating ursid species on the basis of canine morphology, but the canines of ursine ursids, and also of the spectacled bear, show greater resemblance among the species than the marked differences in feeding ecology would suggest. This could be in part due to a short evolutionary history, and in part due to canines not having been subjected to much evolutionary selection as has been the case among other large carnivores, such as large felids. Ursids are probably evolutionarily and ecologically successful due to physical size and strength rather than a derived craniodental anatomy. J. Morphol., 2008. © 2008 Wiley‐Liss, Inc.     

犬科、猫科动物细小病毒血清抗体调查

肉食兽细小病毒属于细小病毒科、细小病毒属中的一类病毒,能够感染多种动物,导致犬的出血性肠炎、幼龄犬的心肌炎、猫的白细胞减少、出血性肠炎、幼龄猫的共济失调症以及水貂的肠炎等多种疾病.血清学调查发现,由肉食兽细小病毒引起的疾病存在于世界各地.在我国,无论是家养还是野生动物均有细小病毒相关疫病的流行,对我国犬科和猫科动物的生存和健康构成巨大威胁(许树林等,1996;宋桂强等,2007).     

Sexual dimorphism of the canine roots in theMacaca fuscata

In situ radiographic analysis of the maxillary canines ofMacaca fuscata was conducted on 88 specimens in 44 individuals (23 dry skulls and 21 live animals) in order to examine the number of roots. The left canines were then extracted from ten female skulls for measurement, further radiographic examination, and visual morphological observation. The results showed a clear sexual dimorphism in root morphology: all male canines were clearly distinguished as single-rooted from the radiograph, whereas more than 40% of the female canines were double-rooted. Variation was also found among the single-rooted female canines, in that some of these teeth appeared to have a bifurcated canal. This sexual dimorphism in the number of maxillary canine roots and the individual variation found among the females in root and canal morphology are previously unreported for this species. No observations were attempted on mandibular canines, however, because of the incomplete nature of the sample.     

First complete restoration of the Oreopithecus skull

The crushed skull ofOreopithecus bambolii (IGF 11778) has been fully reconstructed in Florence, Italy and shows important differences with previous drawn reconstructions. The jaws are massive and projecting, such that the face is not as short as was believed. The incisors are small and do not project significantly forward beyond the position of the canines, and the anterior symphyseal surface of the mandible projects in front of the canines and well infront of the upper canines and incisors. There is a prominent sagittal crest, a high ascending mandibular ramus, and a nuchal plane which faces postero-inferiorly.     

Evidence of testicular dysgenesis syndrome in the dog

Human male reproductive disorders comprising testicular dysgenesis syndrome (TDS) have become more prevalent during the last 50 years. These disorders include cryptorchidism, hypospadias, decreased semen quality, and the development of seminomas. Based on experimental evidence, it has been suggested that environmental pollutants with oestrogen-like or anti-androgenic activities play a role in the pathogenesis of TDS. In humans, histological lesions associated with TDS have been well characterized; this includes seminomas as well as their precursors, carcinoma in situ (CIS) lesions. CIS are seminiferous tubules lined by gonocytes and are a sign of testicular maldevelopment. Such CIS have recently been described in canine species, and an increased frequency of testicular tumours in dogs has also been reported. In this study, we investigated the presence of TDS lesions in canine testes submitted to routine histological examination. Histological features considered typical of human TDS were observed in 8/38 dogs examined; as in humans, individual dogs presented with various TDS features with a range of severity. In all eight dogs, CIS and at least one of the histological feature of TDS was observed in combination with seminoma. These findings suggest that as in humans, TDS may predispose canines to develop testicular cancer. A larger study is needed to better evaluate the actual incidence of TDS in canines, its clinical consequences, and the possible underlying pathogenic factors.     

MYBBP1A: a new Ipr1’s binding protein in mice

Infection with mycobacterium tuberculosis (MTB) can cause different outcomes in hosts with variant genetic backgrounds. Previously, we identified an intracellular pathogen resistance 1 (Ipr1) gene with the role of resistance of MTB infection in mice model. However, until now, its binding proteins have been little known even for its human homology, SP110. In this study, the homology for mouse Ipr1 in canines was found to have an extra domain structure, h.1.5.1. And 30 potential candidate proteins were predicted to bind canine Ipr1, which were characterized of the interacting structure with the h.1.5.1. Among them, MYBBP1A was verified to bind with both Ipr1 and eGFP-Ipr1 in mouse macrophage J774A.1 clone 21 cells using co-immunoprecipitation method. And with the constructed high-confidence Ipr1-involved network, we suggested that Ipr1 might be involved in apoptosis pathway via MYBBP1A.     

Morphological evidence for the biological role of caniniform teeth in combtooth blennies (Blenniidae, Teleostei)

Combtooth blennies have recurved, fang-like caniniform teeth at the rear end of a single row of incisiform teeth. The lengths and positions of these canines were measured in the lower jaws of males of 14 species of Mediterranean Blenniidae. In four species, lower jaw canines were measured in males and females, while in one species, the upper jaw canines of both sexes were also measured. Relative (to body length) canine length in males tends to be significantly greater (10–40%) than in females. There are significant interspecific differences in relative canine length, with smaller species tending to have relatively larger teeth. No significant correlation was obtained between canine length and importance of animal prey in the diet, nor with 'hole fit' of males, which may be related with the intensity of paternal care. We suggest that canines in combtooth blennies are predominately used for predator deterrence and agonistic interactions.     

SEX DETERMINATION OF THE CALIFORNIA SEA LION (ZALOPHUS CALIFORNIANUS CALIFORNIANUS) FROM CANINE TEETH

Size of canine teeth from California sea lion ( Zalophus californianus californianus ) carcasses is shown to be useful in determining the sex of animals which have missing genitalia or which are otherwise of unknown sex. A total of 267 canine teeth from carcasses of 68 males and 43 females were measured along five axes. Of root and crown measurements of upper and lower canines, males and females overlapped only in root thickness of upper canines. A multivariate ANOVA showed a significant difference in the size of canines between upper and lower canines, and between males and females. Stepwise discriminant analysis produced discriminant functions for upper and lower canines for determining sex of unknown-sexed California sea lions. A separate set of canine teeth from 39 male and 49 female California sea lions was correctly classified without prior knowledge of sex by visual inspection and by the two discriminant functions.     

Brief communication: physiological stress in the Florida Archaic-enamel hypoplasia and patterns of developmental insult in early North American hunter-gatherers

We examined the prevalence and developmental timing of linear enamel hypoplasias (LEHs) in an early Archaic Floridian population from Windover (8,120-6,980 (14)C years B.P. uncorrected). Using digital images, mandibular and maxillary canines were analyzed for defect prevalence and timing of insults. Although overall prevalence was very weakly correlated with earlier defect timing, there were significant differences in defect prevalence that varied by sex and tooth type. The mean LEH count in male mandibular canines was far higher than in male maxillary canines or in female mandibular or maxillary canines. We examined defect timing as a possible predictor of the sex differences in LEH prevalence. There were no significant sex differences in the developmental timing of the earliest defects in either tooth class. Developmental timing is not responsible for the sex differences seen in defect prevalence in mandibular canines.     

Performance constraints in strength events in dogs (Canis lupus familiaris)

Ecological performance in animals is considered to be constrained by trade-offs between structural and physiological features. Some of the best anatomical and physiological data in support of this perspective are based on findings from canines, in which researchers have demonstrated skeletal shape trade-offs between running efficiency and strength. There has, however, actually been little examination of the link between these structural differences and relevant performance. In this paper I analyze the performance of six breeds of dogs in standardized weight pulling competitions. More brachycephalic shaped (broad headed) dogs are indeed significantly stronger than more dolichocephalic shaped (narrow headed) dogs even when controlling for body mass. Morphological trade-offs between power and running ability may be an important constraint on the evolution of canines and other terrestrial vertebrates.     

Canine morphology in the larger Felidae: implications for feeding ecology

Canine morphology is analysed at seven intervals along the crown in both anteroposterior and lateromedial perspective in seven species of large felids. The puma and the snow leopard have stout, rather conical canines, whereas those of lions, jaguars, and tigers bear substantial resemblance to each other, reflecting their phylogenetic relationships, and are less conical and large. The canines of the leopard are intermediate in morphology between those of the other species, probably reflecting its more generalized diet. The clouded leopard has very large and blade-like canines, which are different from the other analysed species. Canine bending strengths to estimated bite forces appear to differs less among the species than morphology, indicating that the evolution of canines has been constricted with respect to their strength in failure, probably owing to their being equally important for species fitness. However, the clouded leopard again stands out, having a high estimated bite force and rather weak canines in bending about the anteroposterior as well as lateromedial planes compared to the other species. Canine morphology to some extent reflects differences in killing mode, but also appears to be related to the phylogeny. The marked divergence of the clouded leopard is presently not understood.  © 2007 The Linnean Society of London, Biological Journal of the Linnean Society , 2007, 91 , 573–592.     

Der Bau der Canini bei den Paulchoffatiidae (Multituberculata; Ober-Jura)

Canines are preserved among Multituberculata only in the upper jaw of the Paulchoffatiidae, the Pinheirodontidae and the North American genusGliodon Engelmann &; Callison, 1999. They resemble the anterior premolars (p^1–3) in the morphology of their crown, but they differ from them by the presence of only one root. In the present paper, 126 isolated canines of the Paulchoffatiidae from the Guimarota coal-pit in Portugal are treated. They show a wide morphological variation, from bicuspid to pentacuspid expression, and they can be grouped into 18 morphological units (Tab. 1). The bicuspid canines (11 specimens) show one buccal and one lingual cusp, arranged side by side, the latter normally being larger than the former. In the tricuspid canines (32 specimens) the cusps (one buccal and two lingual) are arranged in a triangle, with a great variation in the position of the cusps to each other. Tetracuspid canines (69 specimens) are the dominating group. Two buccal and two lingual cusps are present, which differ markedly in their largeness and their position to each other. The teeth differ also much in the shape of their crown. The pentacuspid canines (14 specimens) show two buccal and three lingual cusps. The variation in the arrangement of the cusps and in the shape of the crown is similar as in the tetracuspid specimens. One or two small cuspules can be present at the anterior border of the crown additionally to the main cusps in the canines. Tricuspid and tetracuspid canines are present also in the skulls of the Paulchoffatiidae, whereas bicuspid and pentacuspid canines are known only as isolated specimens. In the Pinheirodontidae the canines are tricuspid or tetracuspid, inGlirodon they are unicuspid. The Paulchoffatiidae and Pinheirodontidae — Paulchoffatiid line sensuKielan-Jaworowska &; Hurum, 2001 — are characterized by increasing premolarization of the upper canines. With that they differ markedly from all other multituberculates where the canini become reduced.     

Haemobartonella canis infection in research dogs.

During 1970-1972 haemobartonellosis occurred in research canines at 2 widely separated institutions. Clinical anemia occurred in a splenectomized dog at a Maryland facility, and subsequent screening disclosed an infection rate of 65% in a group of 20 splenectomized subjects. Treatment was successful, and the animals were used in research. A research institution in Texas encountered a number of dogs with fever (to 106 degrees F) and eosinophilia (to 42%) following minor surgery. Blood from affected animals was injected iv into splenectomized dogs, and 3 of 6 recipients developed haemobartonellosis. Further study was conducted, with some success, to establish a relationship between fever and eosinophilia and Haemobartonella canis infection in nonsplenectomized subjects. Our experiences suggest that haemobartonellosis is a widespread, latent disease of dogs and that significant potential exists for the infection to adversely affect research results.     

Seroprevalence of Neospora caninum antibodies in dogs in India

Neospora caninum is one of most important causes of abortion in cattle worldwide, and dogs are an important risk factor for N. caninum infection in cattle. Antibodies to N. caninum were determined in 184 (126 rural, 58 urban) dogs from the Punjab State, India, using commercial monoclonal antibody-based competitive ELISA and found in 16.8% of the animals. The prevalence of N. caninum antibodies was significantly higher in rural dogs (21.4%, 27 of 126) than city dogs (6.9%, 4 of 58). To our knowledge this is the first report of N. caninum infection in canines from India.