Topography of the location of mental foramen in dried edentulous human mandible and its clinical implication

The mental foramen is an oval or round opening on external surface of mandible and transmits mental nerve and vessels. Mostly located at apex of second mandibular premolar or between the apices of premolars. The study was commenced on 60 dried edentulous mandibles with the aim to determine location of mental foramen(MF) with reference to surrounding anatomical landmarks. By measuring its distance from midline (symphysis menti), posterior border of ramus of mandible, lower border of mandible. Length of lower border (Base) of mandible was also measured. In present study most common shape of mental foramen was round (70%). The mean distances of MF from midline are 24.36mm on right side and 24.15mm left side. From posterior border of ramus are 64.45mm on right side and 64.15mm on left side. From base of mandible are 12.29mm on right side and 12.48mm on left side. Length of base mandible (midline to angle of mandible) is 83.27mm right side and 83.12mm left side. Ratio of distance from symphysis menti to MF and length of base of mandible are same on both sides that are 0.29. There is statistically significant positive correlation between distance from symphysis menti to MF and length of base of mandible.The MF plays a very important role in treatment planning and its location needs to be considered prior to placement of dental-implants, regional anesthesia, osteotomy-surgeries and during complete denture-fabrication in order to avoid MN injury and related complications.

Morphology, morphometry and some aspects of clinical anatomy in the skull and mandible of Sharri sheep

The aim of this study was to investigate and record data on the morphometrical parameters of the skull and mandible in Sharri sheep. We have evaluated 34 skulls (24 females and 10 males) of Sharri sheep (Ovis aries), a local breed of sheep from Northern Macedonia. Fifty-one measurements were evaluated in total: 37 parameters on the skull and 14 parameters on the mandible. The results of the study show that, in general, the morphology and morphometric parameters of the skull and mandible, of Sharri sheep are similar to those of other sheep breeds with few differences. The mean skull length (SL), skull height (SH), distance between two supraorbital foramina (DBTSF), orbital length (OL), mandible length (ML) and Sharri sheep diastema (D) were 247.47 ± 13.12 mm, 104.71 ± 6.21 mm, 50.73 ± 3.44 mm, 41.21 ± 1.99 mm, 185.91 ± 13.33 mm and 45.81 ± 3.73 mm, respectively. The results also show that out of 51 parameters, only 13 show a statistically significant difference between females and males, particularly the distance of akrokranion to opisthion (AO), articular surface length of mandibular condyle (ASL) and anterior limit of the mandibular foramen to cranial border of ramus mandible (RBMFRMRM). The findings of this study are important in many aspects: morphologically, morphometrically and especially clinically, during surgical interventions in the head region. With a lack of information in current literature on the investigated parameters in this sheep breed, the present data are a solid basis for further studies in comparative anatomy with other ruminants and in other areas such as zooarchaeology and animal welfare.

Termites (Insecta: Isoptera) diversity in forest conseccion areas of PT Inhutani I, Indonesia

Termites as wood biodeterioration agents have an important role in the ecosystem. This study aimed to observe termite diversity. A termites survey was conducted on Forest Concession Areas of PT. Inhutani I, South Sulawesi Indonesia. The termite specimens collected used the standardized transect sampling protocols at three different sites (forest with mixed vegetation, Pinus merkusii plantation, and logged-over area; and measurement of nine morphological characters of the soldier was conducted, i.e: head length without mandibles, head width at base of mandible, maximum width of head, left mandible length, pronotum length, maximum width of pronotum, postmentum length, postmentum width of postmentum, and the number of antenna segments. The results showed that there are four species found based on the morphological characteristics and morphometrical data, namely: Odontotermes javanicus., Nasutitermes sp., Schedorhinotermes sp. and Coptotermes curvignathus. The highest termite abundance was found in forest with mixed vegetation. The termite diversity in logged-over area and forest with mixed areas was moderate, while species diversity in pine plantation was low.

Dentition and body condition: tooth wear as a correlate of weight loss in roe deer

Background In many mammalian species, once the permanent teeth have erupted, the only change to dentition is a gradual loss of tooth surface/height through wear. The crown of the teeth cannot be repaired once worn. When dental crown tissue has been depleted due to wear, the animal is expected to have a suboptimal body condition. We evaluated the role of tooth wear in causing a reduction of physical condition in adult roe deer females (Capreolus capreolus). Results The progressive wearing of the lower cheek teeth was assessed in a Northern Apennines (Italy) population with a new scoring scheme based on objectively described tooth characteristics (morphotypes) being either present or absent. Eviscerated body mass and mandible length, which is a good proxy for body size in roe deer, were related to the tooth wear score by the use of linear regressions. The sum of wear scores for molariform teeth correlated most strongly with body condition (i.e., eviscerated body mass/mandible length), showing the importance of the entire chewing surface for acquiring energy by food comminution, chewing, and digestion. In comparison with individuals of comparable size experiencing minor tooth wear, the body mass of those with the most advanced stage of tooth wear was decreased by 33.7%. This method was compared to the height and the hypsodonty index of the first molar, the most commonly used indices of tooth wear. The sum of molariform wear scoring scheme resulted in a more suitable index to describe the variation in body condition of roe deer. Conclusions Describing tooth wear patterns in hunted populations and monitoring at which tooth wear level (and therefore dental morphotype) an animal is no longer able to sustain its physical condition (i.e. when it begins to lose body mass) can be a useful tool for improving the management of the most widespread and abundant deer species in Europe. At the same time, such an approach can clarify the role of tooth wear as a proximate cause of senescence in ungulates.

Determination of Larval Instars of Semanotus bifasciatus (Coleoptera: Cerambycidae) Based on Frequency Distributions of Morphological Variables

Semanotus bifasciatus Motschulsky (Coleoptera: Cerambycidae) is one of the most destructive pests of Platycladus trees in China. Morphological measurements, such as head capsule (HC) width, can be very useful and practical indicators for identifying larval instars of coleopteran species. In this study, six morphological variables, including HC width, pronotum width, mandible length and width, and body length and width were measured to determine the instars of field-collected larvae of S. bifasciatus. Both the HC width and pronotum width were reliable parameters for determining the instar and stage. Larvae of S. bifasciatus were divided into eight instars; we detected strong relationships between larval instar and both the HC width (R2 = 0.9640) and pronotum width (R2 = 0.9549). The ranges of body widths and lengths for each instar are provided as reference values for distinguishing among larval stages in field investigations.

Comparison of reliability of measurements among fetal facial profile parameters by operators with different levels of experience at 15-23 weeks of gestation

Background Mandible anomalies are associated with many syndromes. Various methods have been proposed to assess fetal mandibles with different reliability. This study aimed to compare the reliability of measurements among five fetal facial profile parameters by operators with different levels of experience, at 15–23 weeks of gestation in Thai fetuses. Methods An observational study was prospectively conducted. The inferior facial angle (IFA), anteroposterior mandibular diameter (APD), mandible width (MD), maxilla width (MX) and mandible length (ML) were measured in 123 normal fetuses, using 2D ultrasonography, by 3 operators with different levels of experience. Each participant was examined by 2 operators. Each operator performed three independent measurements for each parameter and was blinded to the results of the other. Reliability of measurement was evaluated using intraclass correlation coefficient for both intraobserver and interobserver variabilities. Bland-Altman analysis was used to evaluate the agreement between operators’ measurements. Results The success rate of ML measurement was highest (100%) among the five parameters for all operators. Failure of MX measurement was high in fetuses at a gestational age of less than 18 weeks. Intraobserver variabilities of APD, MD, MX and ML measurements were excellent for all operators (ICC 0.958–0.986), while those of IFA measurement was moderate to excellent (0.560–0.923), depending on the operators’ experience. Interobserver variabilities varied between pairs of operators; only 2 parameters, APD and ML, showed excellent interobserver variabilities for both pairs of operators (ICC > 0.9) with good agreement. Interobserver variabilities of MX measurements for both pairs of operators were good (ICC 0.606–0.709), while MD was excellent for operator 1 and 2 (ICC 0.867), but moderate for operator 1 and 3 (ICC 0.576) and IFA was good for operator 1 and 2 (ICC 0.602), but poor for operator 1 and 3 (ICC 0.128). Conclusions The reliability of ML measurement was the highest, followed by APD, while IFA was the lowest, among the 5 parameters. ML and APD measurements were feasible and reproducible, whereas MX measurement was limited in fetuses with a gestational age of less than 18 weeks. Additionally, reliability of IFA measurement depended on the operator’s experience.

Determining sex of adult Pacific walruses from mandible measurements

Pacific walruses (Odobenus rosmarus divergens) play a vital role in Arctic marine ecosystems and the subsistence lifestyle of Alaska Native communities. Museum collections contain numerous archaeological and historic walrus specimens that have proven useful in a variety of studies; however, for many cases, the sex of these specimens is unknown. Sexes of adult (> 5 years determined by tooth aging) Atlantic walruses (Odobenus rosmarus rosmarus) have been accurately determined in previous studies using mandible measurements. We tested the validity of this approach for Pacific walruses, and used full fusion of the mandibular symphysis to define adults. Using high precision digital calipers (± 0.01 mm), four measurements were taken either on the left or right side of 91 walrus mandibles: 80 modern mandibles (70 known-sex specimens; 10 unknown-sex specimens) and 11 archaeological mandibles of unknown sex. We used linear discriminant function analysis (LDFA) to determine what measurements best distinguished Pacific walrus males from females. Minimum mandible thickness had the most predictive power, whereas mandible length, height, and depth, were less predictive. Posterior probabilities indicated that LDFA classified the known-sex Pacific walruses with 100% accuracy, and unknown sex with ≥ 90% probability. The ability to define the sex of unknown individuals accurately could greatly increase the sample size of future projects dealing with skeletal remains, and will improve future research efforts.

A Novel Method for Increasing the Numerousness of Biometrical Parameters Useful for Wildlife Management: Roe Deer Mandible as Bone Model

Study of dimensions (biometry) and shapes (geometric morphometry) of bone structures in ungulates is of extreme importance in wildlife population management. Unlike classical biometry, which involves the use of a caliper for measurements, geometric morphometry acquires, through software, a series of reference points (landmarks) from digital photos, providing a series of linear measures. A method to convert values obtained from the GeoGebra software into biometric measures is described. We took photos of 25 mandibles of adult roe deer and at the same time measured mandible length and teeth row length using a caliper. After image processing using GeoGebra, we calculated the conversion factor as the mean ratio between measures taken using GeoGebra and the caliper. The series of measurements, taken with two different methods (direct measurement using the caliper and conversion from GeoGebra output), showed a good degree of agreement. We used the conversion factor to obtain, from the GeoGebra database, four additional parameters of 50 mandibles. The analysis of variance showed that one parameter was significantly different between sexes (p = 0.04), demonstrating the usefulness of the measurement conversion. The conversion factor is helpful to improve classical biometric databases to better clarify the relationship between environment and wildlife status.

Allometry and Fighting Behaviour of a Dimorphic Stag Beetle Cyclommatus mniszechi (Coleoptera: Lucanidae)

Male stag beetles (Coleoptera: Lucanidae) use their mandibles as weapons to compete for resources and reproduction. Mandible size in stag beetles can be associated with different behaviours and the outcome of male contests. We investigated the allometric relationship between mandible and body size in males of the stag beetle Cyclommatus mniszechi to uncover distinct morphs. The results divided male C. mniszechi into majors and minors with the switch point of mandible length at 14.01 mm. The allometric slope of mandibles was positive for both morphs but was steeper for the minors. We also characterised the fighting behaviour of the different morphs in size-matched contests using sequential analyses. Males matched each other’s behaviour in contests with many physical contacts, no injury and a progression from low towards high aggression and rare de-escalation. Major and minor males employed the same behavioural elements in contests, but major males were more likely to escalate directly into more aggressive phases and minor males tended to stay within phases. This finding suggests that major males may compete more aggressively than minor males in contests.

A new species of snook, Centropomus (Teleostei: Centropomidae), from northern South America, with notes on the geographic distribution of other species of the genus

Centropomus irae sp. nov. (Centropomidae) is described from two localities in the state of Amapá, northern Brazil. The new species differs from all its congeners by the typically brown-colored lateral line, the relatively smaller mean interorbital width (4.1% of SL vs. 5.2–6.9%), mean snout length (8.9% of SL vs. 9.8–11.1%), mean diameter of the orbit (4.5% of SL vs. 5.4–7.3%), and mean mandible length (15.7% of SL vs.19.9–21.6%). The new species can also be distinguished from the similar Centropomus undecimalis by the number of scales around the caudal peduncle (18–23, usually 19–21, vs. 22–28, usually 24–27). With Centropomus irae sp. nov., seven species of the genus are now known to occur in the western Atlantic. The distribution of Centropomus in Brazilian waters is updated and a key to the species of this genus is presented. [Zoobank URL: urn:lsid:zoobank.org:act:3D497B38-48A5-4A6E-B377-6D57E82D4DE4[