Male Skulls Research Articles

Natural mortality patterns in a population of southern argentina huemul(HIppocamelus bisulcus), an endangered andean cervid

The huemul(Hippocamelus bisulcus), an endangered deer living in the Andes of southern South America, numbers 600–700 in Argentina, from at least 63 fragmented subpopulations. Very limited information exists on most populations, but there are indications that the distribution and population sizes continue to diminish, possibly through reduced reproductive rates, elevated mortality rates or both. This is the first analysis of the population ecology of a subpopulation in Argentina, made possible through the only existing compilation of numerous remains of dead huemul (n=19). Surveys were conducted between 1993 and 1999 to locate and collect remains, which were found concentrated at lower elevations. The sex ratio of adults and subadults (n=12) was 1:1, but could not be determined for fawns. Clear signs of predation was found in 37% of all deer: 50% among calves, 50% among subadults and 31% among adults. These signs occurred in 29% of adult females and 50% of adult males. Deaths occurred during winter as judged by the state of the male skulls, which indicated the phase of the antler cycle. Femur fat content of 3 deer averaged 93%. Predation signs frequently were clearly from puma(Puma concolor), which is the only natural predator of huemul. The high predation rate, high marrow fat content and no indications of deaths resulting from disease corroborate the pristine state of the of mature lenga(Nothofagus pumilio) forest. The area with a concentration of huemul carcasses appears to be the huemul's major winter habitat.

Brief communication: neurotraumatological aspects of head injuries resulting from sharp and blunt force in the early medieval period of southwestern Germany.

Approximately 10% (33 of 304) of the predominantly male skulls from the 6th through 8th centuries in southwestern Germany exhibit cranial fractures derived from blunt or sharp force trauma. No evidence of fracture healing characterizes 24% (n = 8) of these individuals. All nonhealed fractures were caused by sharp force, and four of these wounds cross the sagittal sinus. The lengths of these straight-edged wounds, produced exclusively by sword blows, measure around 8.0 cm for fatal, and about 5.0 cm for nonfatal wounds. Seventy-six percent (n = 25) of these skulls exhibit some healing, which indicates that these injuries did not lead to immediate death. In this group are all depressed fractures resulting from blunt force blows. Two thirds of the 45 cranial injuries noted on these 33 skulls are located on the left side of these individuals, with a concentration in the frontoparietal region. Bony indications of wound infection occur in four cases (12%). Three crania exhibit circular trepanations in association with fractures. These phenomena are discussed in the context of modern neurotraumatological knowledge.

Relationships among facial type, buccolingual molar inclination, and cortical bone thickness of the mandible.

The purpose of this study was to evaluate the relationships between different facial types, and both the buccolingual molar inclination and cortical bone thickness of the mandible. The material consisted of 31 dry skulls of modern Japanese males from the Museum of the University of Tokyo. They all demonstrated normal occlusion with minimal dental discrepancy, and without crossbite or facial asymmetry. The buccolingual inclination of the second molar (M2) in the long-faced subjects was significantly smaller than the same dimension in the average- and short-faced subjects. It was found that the teeth of long-faced subjects were more lingually inclined than those of the short-faced subjects. The cortical bone thickness of the first molar (M1) and M2 sections was thicker in short-faced subjects than in average- and long-faced subjects. The results of this study provide evidence that a significant, but complex relationship exists between structures of the mandibular body and facial types. The morphological features that relate to masticatory function and facial types are associated with the cortical bone thickness of the mandibular body, and the buccolingual inclination of the first and second molars.

Skull development of the California sea lion (Zalophus californianus californianus)

This work describes the skull development in males and females of the California sea lion (Zalophus californianus californianus) examined in 87 specimens collected in the Gulf of California between 1982 and 1991. Forty-three measurements, nine qualitative characters and the number of upper-canine-tooth dentine layers, in addition to the natal layer, were recorded. Growth parameters were calculated with the von Bertalanffy equation and Cartesian distortions were used to schematize the skull development. To simplify the description of development, the skull was divided into the following parts: (1) braincase, (2) auditive apparatus, (3) masticatory apparatus and (4) nasal apparatus. Males with zero tooth dentine layers have skulls slightly smaller than those of females but they grow faster. Male skulls grow larger than those of females but the older males in the sample examined seem to have bone reduction. The most frontal ridge and sagittal crest are structures with evident asymmetry. Sexual dimorphism may be recognized in the skull proportions since birth. The female skulls grow fairly uniform I time, as well as in length and width. In the males, the skull grows more in length after birth and more in width thereafter. This heterogeneity is more marked in the masticatory apparatus. The capacity of bone remodeling in the different parts is not related to their degree of sexual dimorphism. The variation in the sample examined shows the need to study skulls developoment in relation to geographic and environmental variations, as well as in relation to the habits of the animals throughout their life.

Is the complexity of the human sagittal suture related to the size of the temporal muscle?

We have tested the hypothesis that temporal muscle size determines the degree of interdigitation of the human sagittal suture by comparing male and female skulls of Europeans and Australian aborigines. Temporal muscle length, area of the temporal aperture and estimated muscle volume were greater in males than in females of each racial group. Sexual dimorphism of the complexity of the sagittal suture was not confirmed in either race. However, the suture was less complex in aborigines than Europeans despite the volume of the temporal muscle being larger in the former group. We conclude, therefore, that although the morphology of the sagittal suture is an epigenetic character, it is not mechanically influenced by muscle size. A simple quantitation of suture form may however be useful in assigning unknown skulls to a particular race.

Sellar Pathology in a middle Bronze Age skull from Southern Italy

AbstractThis paper describes a case of an intrasellar tumour found in a male skull from Southern Italy dating from the middle Bronze Age. The sella turcica shows considerable enlargement in all diameters, erosion of the dorsum and marked depression of the floor. These features are consistent with a diagnosis of pituitary tumour, probably a non‐secreting adenoma.

Skull variability of Mustela nivalis Linnaeus, 1766 in Poland

The skull variability of Mustela nivalis Linnaeus, 1766 was studied with regard to age, sexual dimorphism and geographical distribution. The material consisted of 271 skulls from Poland. Linear dimensions of weasel skulls slightly increased with age. The changes in skull proportions were related to braincase diminution and increase in viscerocraniu m. In females, there was an obvious age variation in correlation structures which indicated synchronic growth and periods of stabilization. Sexual dimorphism was expressed by larger dimensions and different proportions in male skulls. The values of coefficients of variation were higher in males than females. Adult skull size was reached earlier by females than by male weasels. The correlation structures of male and female skulls were different. The skull dimensions increase from north-east to south-west Poland. It was revealed, that weasels from Poland but Silesia belong to the subspecies Mustela nivalis vulgaris Erxleben, 1777. Weasels from Silesia may probably form a separate subspecies Mustela nivalis trettaui Kleinschmidt, 1937.

A Decapitated Human Skull from Medieval Kamakura.

The present study reports on the examination of a decapitated human male skull with four upper cervical vertebrae and the hyoid bone, dating to the early Muromachi period (late 14th century), from Kamakura. The decapitation may have been the result of a sharp cut from the right rear. The cut runs horizontally into the second cervical vertebra and stops in the bone, after having severed both the spinal cord and the right vertebral artery. Superficial injuries to the skull were probably not the primary cause of death. The head was separated from the body post mortem, probably as a result of an additional cut noted in the fourth cervical vertebra. It is suggested that the traditional Japanese method of decapitation in former times may be characterized by a cut halfway through the neck, and this method of decapitation can be traced back to the early Muromachi period.

Continuous tooth eruption in Australian aboriginal skulls

Increases in the distance from the cemento-enamel junction to the alveolar crest (CEJ-AC) have often been attributed to senile atrophy of the bone or to the effects of periodontitis, without reference to the condition of the alveolar crest. This study investigated the relationship between CEJ-AC distance, tooth wear, gender, site of the CEJ-AC measurements, and age in 161 pre-white-contact Australian aboriginal skulls. Individual teeth were included in the study when there was no evidence of dehiscence, periodontitis, or abscess cavity formation in the supporting alveolar bone. The CEJ-AC distances increased as the severity of attrition increased; in male skulls, CEJ-AC distances were greater than in female skulls for all categories of tooth wear. In general, CEJ-AC distances measured on the mesial aspects of teeth were greater than those recorded distally; lingual distances generally exceeded buccal recordings. The best explanation of these findings and similar reports in the anthropological literature is that continuous tooth eruption occurred without the concomitant coronal movement of alveolar bone. This conclusion has significant ramifications for anthropological, epidemiological, and clinical studies which use the CEJ and AC as reference points when measuring periodontal attachment loss (periodontitis).

Relationship Between the Piriform Aperture and Interalar Nasal Widths in Adult Males

The piriform aperture of 182 skulls of black and white males in the United States was measured and compared with soft tissue readings taken previously. Statistical analysis indicated that nose width prediction formulas currently utilized in facial reconstruction required modification. Two revised formulas are proposed to improve accuracy of reconstructions: an addition prediction formula for ease of use and a multiplication prediction formula for more precise results on those skulls outside of the mean range.

CT reconstruction of the Glabellar bone

During systematic archaelogical excavations of the early medieval kingdom of Serbia, and adult male skull belonging to the skeleton of a Roman individual was unearthed at Babrež site in the Ras region. A supernumerary bone was found interposed between the frontal bones of the skull and the facial skeleton. Paleopathological investigation and CT reconstruction proved that this skull had been deformed during foetal development due to a disorder or disease affecting the mother. This probably led to the formation of the supernumerary Glabellar bone in the frontal region. This is the first case of Os Glabellae recorded so far.

Sex identification and sexual dimorphism in the skull of the stone marten, Martes foina (Carnivora, Mustelidae) / Identificazione del sesso e dimorfismo sessuale nel cranio della faina, Martes foina (Carnivora, Mustelidae)

Abstract Morphometric variation in 62 characters of 84 skulls of Martes foina from Italy was analyzed. Stepwise discriminant analysis was used to estimate three discriminant functions as craniometric keys for sex determination. The first two keys were based on absolute measurements, the third on absolute and relative measurements. This last key seems to be the best and provides 89.8% correct classification for males and 91.4% for females. Parametric or nonparametric univariate methods, analysis of cases, and principal component analysis (PCA) were used to investigate morphological differences between skulls of males and females. In Martes foina the sexual dimorphism is more due to the size than to the shape, unlike other Mustelids. The size dimorphism was shown to be related to the measurements of the masticatory apparatus, like in other Mustelids. Riassunto Sono state analizzate statisticamente le variazioni morfometriche di 62 parametri su 84 crani di Martes foina provenienti da collezioni museali italiane. L'analisi discriminante stepwise e stata utilizzata per calcolare tre funzioni discriminanti quali chiavi craniometriche per l'identificazione del sesso. Le prime due chiavi sono basate su misurazioni assolute, la terza su misurazioni sia assolute che relative. Quest'ultima chiave sembra essere la migliore e fornisce ne11'89,8% dei casi una corretta classificazione degli individui di sesso maschile e nel 91,4% dei casi degli individui di sesso femminile. L'analisi univariata di tipo parametrico o non parametrico e l'analisi dei cluster dei casi e della componente principale (PCA) sono state utilizzate per valutare le differenze morfo- logiche esistenti tra i crani delle femmine e dei maschi. In Martes foina il dimorfismo sessuale e dovuto alle dimensioni piu che alla forma, a differenza di altri Mustelidi. Si e osservato che tale dimorfismo nelle dimensioni puo essere correlato con le misure relative all'apparato masticatorio, come in altri Mustelidi.

Correlates of enamel hypoplasia with human dental reduction.

Human dental reduction has been manifested in evolutionary and secular trends, but it is not known to what degree each of these complementary processes contributes to changes in tooth size. Enamel hypoplasia is a marker of developmental stress that is often found to be of greater frequency and severity in populations undergoing dental size reduction. In order to test the developmental association of enamel hypoplasia with tooth size, measurements of bucco-lingual and mesio-distal diameters were taken on teeth of 54 black male skulls from southern Africa. Those dentitions that exhibited incisal enamel hypoplasia were significantly reduced in size as compared to those showing no signs of developmental stress. A distinct pattern of reduction emerged: the bucco-lingual diameters of the I1 , I2 , P3 , P4 , M1 , and M2 were significantly reduced, whereas the mesio-distal diameters of only the I2 and M2 decreased in size. The I2 and M2 showed the greatest degree of reduction despite the lack of macroscopic enamel hypoplasia on the M2 . Application of the data to the variety of dental reduction patterns evinced in modern and ancient populations indicates that factors including tooth shape, developmental timing of stress, and genetic determinants of tooth size must be considered in order to partition evolutionary and secular trends in the dentition.

Craniometric variation in Norwegian wolverines Gulo gulo L.

Craniometric variation in Norwegian wolverines was analysed using univariate and multivariate techniques. The wolverine skull seems to be full-grown after about 9 months in both sexes although some dimensions continued to grow at a slow rate after the first year. Size allometry was studied in skulls older than 11 months. Allometric coefficients were calculated from different methods. The multivariate allometric coefficients were found to reflect the same allometric patterns as were found from the reduced major axis and from the direction cosines of PCI, whereas the coefficients seem to be underestimated by the least-square regression method. Sexual dimorphism was found to be highly significant, males being the larger sex. The female skulls were found to be relatively broader and to have a relatively higher coronoid process than the male skulls. It seems that the females have a relatively stronger feeding apparatus than the males, which leads to less absolute differences in strength, as reflected in a very high degree of dietary overlap. Two discriminant functions were calculated which both classified the material into their correct sex with nearly 100% accuracy. Geographical variation between samples from Nordland and Finnmark counties were studied. No significant multivariate variation was found between the female skulls. The male variation was highly significant; the Nordland skulls seem to have longer carnassials than those from Finnmark.

The temporal region and the supramastoid ridge in mesolithic skulls from Padina in the Iron Gate Gorge of the Danube

Studies of the morphological features of the temporal region of mesolithic skulls from Padina in the Iron Gate Gorge of the Danube revealed a very prominent and large supramastoid ridge which is the most striking feature in skulls of both sexes. Mastoid processes were larger in male skulls, but in 25% of the cases there was an overlap between the size of the processes in male and female specimens. The mastoid ridge was prominent in both sexes. The digastric fossa was always well defined in both sexes and in the two thirds of the skull specimens it was deep. The posterior root of the zygoma was prominent in all the skulls, but it was better developed in the male specimens. The parietotemporal suture in both sexes rises above the level of the pterion. There were no morphological or anthropometrical differences between the left and the right side of individual skulls outside the limits of natural asymmetry. All these morphological characteristics of the temporal region may help in racial and sexual diagnosis of the Mesolithic skulls from the Iron Gate Gorge.

Supraorbital ridge and masticatory apparatus II: Humans (Eskimos)

Thirteen adult male skulls of St. Lawrence Island Eskimos were studied to determine the factor or factors responsible for the development of the supraorbital ridges. Results showed that the determining factor is the ratio of the power arm to the load arm of the mandible. The smaller this ratio, the greater the traction force exerted by the anterior temporalis muscle and the greater the supraorbital ridge. Pearson’s correlation coefficient shows two positive correlations, i.e. between the anterior temporalis muscle and the ridge and between the ridge/sinus and the anterior/whole temporalis muscle. Conversely, there is a negative correlation between the power/load arm and the muscle ratio as well as between the power/load arm ratio and the ridge/sinus ratio.

Correlation coefficients in human skulls: Significant sexual differences

This study of 500 male and female skulls proves: significant differences of correlation coefficients (p less than or equal to 0.01) occur between the two sexes. The combined variables are: 1. bizygomatic breadth (45)/skull base length (5) 2. bizygomatic breadth (45)/foramen magnum length (7) 3. bizygomatic breadth (45)/foramen magnum breadth (16) 4. bizygomatic breadth (45)/basion-bregma height (17) 5. foramen magnum breadth (16)/skull base length (5) Female skulls have generally higher correlation coefficients values than males which is interpreted as an indication of homogeneous growth.

Study of the anatomic metric values of the foramen magnum and its relation to sex.

The sagittal and transverse diameters of the foramen magnum were examined in 100 human skulls (74 male, 26 female). The results were statistically analyzed and compared with those obtained by other authors. Our findings show that the sagittal and transverse diameters are clearly different, as well as the total area of the foramen magnum, these parameters being larger in male skulls than in female.

Influence of food restriction during gestation on craniofacial growth of the weanling rat.

Holtzman rats were subjected to food restriction during gestation or lactation, or both periods (overall stress). At weaning, male pup skulls were measured and female brains and cranial masticatory muscles were weighed and a neuromuscular index was calculated. It was found that gestational protein-calorie malnutrition (PCM) without suckling restoration accounted for about 30% of the growth delay observed under overall stress. That effect disappeared after a normal suckling restoration. Under the same conditions of maternal food restriction in both periods, growth delay in the offspring was greater during lactation than gestation. As in lactation, craniofacial changes during gestational restriction were due to an adjustive response of bone growth to PCM. This response seemed to accrue from an altered relationship between the growth of the brain-less sensitive and highly restorable-and the growth of the masticatory muscles-more sensitive and less restorable. Some degree of delay in orthocephalization would be the skeletal outcome of such adjustive neuromuscular response.

Morphologic Variation in the Coyote, Canis latrans, in the Southern United States

Morphologic variation in the coyote, Canis latrans, from the southern United States was examined using univariate and multivariate statistical analyses. The taxon was sexually dimorphic with male skulls larger for 20 of 21 characters assessed. Fourteen male and 12 female measurements showed significant interlocality variation. A matrix of correlation among characters was computed, and the first three principal components were extracted. These accounted for 87.9% of the total phenetic variance in the character set of males of 94.1% among females. Three-dimensional projection of localities onto principal components showed that, for both males and females, large individuals occurred in more eastern localities (male-eastern Texas, Louisiana, and Mississippi; female-Louisiana, Tennessee, Arkansas, Mississippi, and eastern Texas) and smaller animals occupied western localities (western Texas, Oklahoma, and Missouri). In general, coyotes were most similar to those in nearby geographic areas. Large size for both sexes was positively correlated with high actual evapotranspiration. The coyote, Canis latrans, is widely distributed in North America (Hall, 1981). Much natural history and management information relating to this species has been collected in many parts of its range. Bekoff (1977) summarized much of this available literature. Canis latrans is versatile in relation to food and habitat and appears to be a species that has met the challenges of the modern world. At a time when many species are declining in numbers, C. latrans continues to occupy traditional ranges as well as escalate its distribution into new areas. One region of recent colonization is the southeastern United States. Gipson (1978) reported no wild Canis, other than occasional feral dogs and extremely isolated pockets of red wolves, occurring in the southern states east of the Mississippi River from 1900 until about 1965. Coyotes moved eastward through Tennessee, Mississippi, and other eastern states during the 1960's and early 1970's. The immigration of C. latrans into the southeastern United States offers a rare opportunity for systematic study. The purposes of this study were to examine morphologic variation in C. latrans in the southern United States and to appraise the similarity of coyotes from newly colonized areas of the southeastern United States with those from established portions of the range in the southwest. MATERIALS AND METHODS-We recorded 21 linear skull measurements (Fig. 1) from 552 adult C. latrans. Adult specimens were determined according to criteria of Nellis et al. (1978). Skull dimensions were measured with a dial height gauge (in inches and converted to millimeters) and dial calipers to the nearest 0.1 mm. Characters were chosen following the logic of Kennedy and Schnell (1978). To reduce heterogeneity in sample sizes, specimens were grouped for statistical analyses according to state boundaries with the exception of animals from Texas which, due to the large size of this state, were treated as eastern and western localities. States represented by less than This content downloaded from 157.55.39.112 on Wed, 07 Sep 2016 04:38:02 UTC All use subject to http://about.jstor.org/terms The Southwestern Naturalist