The structural features of the sculls of animals of a series of Carnivore

Predators is medium-sized and large mammal leading a terrestrial way of life. They are mostly carnivorous animals, the nature of nutrition of which indicate certain devices are reflected in the structure of the scull. The aim of the work is to conduct a comparative anatomical study of the structure of the scull and to determine the craniometric indicators in animals of families Feline (Domestic cat), Canine (Domestic dog, Wolf, Fox ordinary) and Mustelidae (stone marten, forest polecat, badger ordinary) a squad of Carnivore. Comparative anatomical, craniological and statistical methods of research were used. It was found that the scull of test animals is of a General anatomical structure (wide temporal fossa, a deep masseteric fossa, well-defined nuchal and external sagittal crests, the presence of angular process on mandible, relatively large tympanic bullas, underdeveloped lacrimal bone) and species differences (topography of split of the external sagittal crest, shape of mandibular angular process, the presence of intratympanical part of the temporal bone). Absolute craniometrical indices of badger more of indicators of marten, since they directly depend on the weight and body size of these animals. There are most vary the overall length of the scull (1.69 times; P < 0.001), length of bony palate (1.82 times; P < 0.001), length of the external sagittal crest (3.67 times; P < 0.001), width of bony palate at the level of the first premolar and the last molar (2.33 times; P < 0.001), width of choans on the level of hook-shaped processes of pterygoid bone (1.75 times; P < 0.01), width of choans at the level of the caudal edge of the Palatine bone (2 times; P < 0.05), the total height of the scull (2.36 times; P < 0.001). Most of the relative craniometric indicators of the badger scull, compared with such in martens, are almost the same, due to the close specificity of nutrition and environmental characteristics in natural biocenosis. Due to the well-developed external sagittal crest, the height of the brain relative to the total height of the scull in badger (61.02 ± 4.73%) is 1.51 times less (P < 0.001) than in marten (92 ± 6.12%). The relative length of the external sagittal crest to the total length of the badger scull is 2.17 times longer (P < 0.001) (53.1 ± 3.09 versus 24.42 ± 1.41%), compared with marten, due to the more powerful development of masticatory muscles, temporal in particular.

Morphometry of the mandibular foramen applied to local anesthesia in hoary fox (Lycalopex vetulus)

ABSTRACT: Great part of the veterinary care in wild carnivores is intended to treat the dental disorders, and oral cavity disorders may generally affect the animal health as a whole. It is factual that knowing the location of the mandibular foramen is vital for local anesthetic block of the inferior alveolar nerve, however, there is still no data on the morphometry of the hoary fox mandibular foramen. The aim was describing morphometry of the mandibular foramen of this species and associating its position with anatomic reference points in the mandible, thus providing support for more effective local anesthetic block of the inferior alveolar nerve in such species. Four adult jaws of Lycalopex vetulus were used. Radiography and biometrics of the hemimandibulas were performed. The rostral third of the jaw body in a lateral view presented three mental foramens, being a rostral, a medium and a caudal. Each hemimandibula presented I3/C1/PM4/M3. The angle of the mandible was marked by the masseteric fossa, the angular incisure, the angular process and the mandibular foramen, and this last one located perpendicularly to the dorsal edge of the angular incisures in medial view. In this view, the crevice to the milohyoid nerve, projected in the caudodorso rostral direction, was also evidenced. The ramus of the mandible was characterized by the presence of the condylar and coronoid processes, and by the dorsal and ventral mandibular incisions. Statistical analyzes did not present significant differences between the antimeres of the studied animals, and the penetration of the needle perpendicularly to the dorsal end of the angular incision on average 8.79mm, overlapped to the medial face of the angle of the mandible could be indicated. Alternatively, the access may also be achieved by inserting the needle in an average of 17.69mm perpendicular to the dorsal end of the angular process, in contact with the medial aspect of the angle of the mandible, and in caudo-rostral projection, also allowing a better anesthetic blockade of the inferior alveolar nerve in L. vetulus. It can also be concluded that the masseteric fossa, the dorsal and ventral mandibular angles, the crevice to the milohyoid nerve, the ramus of the mandible and the mandibular foramen presented differences in their topographic descriptions when compared to the other canids.

A new species of Middle Miocene baleen whale from the Nupinai Group, Hikatagawa Formation of Hokkaido, Japan

A fossil whale from the Hikatagawa Formation (Middle Miocene, 15.2–11.5 Ma) of Hokkaido, Japan is described as a new genus and species Taikicetus inouei and its phylogenetic position is examined. Consistent with the result of Marx, Lambert & de Muizon (2017), the Cetotheriidae form a clade with the Balaenopteroidea, and “a clade comprising Isanacetus, Parietobalaena and related taxa” is located basal to the Balaenopteroidea + Cetotheriidae clade. Taikicetus inouei is placed in the clade with most of members of “Cetotheres” sensu lato comprising Isanacetus, Parietobalaena and related taxa. Taikicetus inouei can be distinguished from the other members of “Cetotheres” sensu lato in having an anteriorly swollen short zygomatic process, high triangular coronoid process, and angular process, which does not reach as far posterior as the mandibular condyle. Taikicetus inouei is only record of “Cetotheres” sensu lato from Hokkaido, Japan and the northern-most records of “Cetotheres” sensu lato in Japan.

Morphology and Morphometry of Mandible of Stripped Hyena (Hyena hyena)

The morphological and morphometrical study of mandibles of hyena was carried out at Sakkarbaug Zoo, Junagadh (Gujarat). The average weight, length and width of mandible was 0.221 kg, 14.25 cm and 1.84 cm, respectively. The mandible was formed by two symmetrical halves fused rostrally by symphysis. The average length of symphysis mandibularis was 4.75 cm. The alveolar border presented six alveoli for lower incisors, two large deep alveoli for canine teeth, three alveoli for premolars and one for molar teeth. The diastemal mandibular length was 2.69 cm. The mental foramen was one. The mandibular height up to condylar and coronoid processes were 9.16 and 6.74 cm, respectively. The distance of mandibular foramen from posterior border was 3.22 cm. The angular process was placed at caudal border of horizontal ramus and found pointed and laterally curved. The average length of angular process was 1.23 cm.

MORPHOLOGY AND MORPHOMETRIC STUDY OF MANDIBLE OF ASIATIC LION (Panthera leo), INDIAN TIGER (Panthera tigris) AND COMMON LEOPARD (Panthera pardus)

The morphology and morphometric study on mandibles of lion, tiger and leopard was carried out at Sakkarbaug Zoo, Junagadh (Gujarat). The mandible is formed by two symmetrical halves fused rostrally by symphysis. The alveolar border presented six alveoli for lower incisors and two large deep alveoli for canine teeth. The average length of mandible was 19.08, 17.40 and 13.54 cm in lion, tiger and leopard, with the corresponding average mandible weight of 0.338, 0.271, and 0.145 kg, respectively. However, the width of mandible was significantly more in lion (3.28 cm) than that of tiger (2.51 cm) and leopard (1.71 cm). The mandibular height up to condyle and coronoid process in lion, tiger and leopard was 4.17 and 9.24, 4.19 and 9.16, 3.04 and 7.14 cm, respectively. Both the heights were significantly higher in lion and tiger than those of leopard. The average length of symphysis-mandibularis was significantly higher in lion (6.58 cm) and tiger (6.68 cm) than leopard (4.47 cm). The mental foramina were three in tiger and two in lion and leopard, and they were deeper in lion and tiger than the leopard. The angular process was placed at caudal border of horizontal ramus and found blunt and medially curved in all three species.

Morphological and morph metric study of the mandible in the local Rabbits (Oryctolagus Cunicuius)

Eleven adult local rabbits (6 female and 5male) were used for this study. The mandible were prepared to study the gross anatomical features. The main gross characteristics feature of the local rabbits mandible the ramus forms a broad, thin and flat plate, the surface of the ramus is greatly increased in its posteroventral portion to form the angle or angular process. The articular surface is elongated and carry on its caudodorsal end a slightly oblique condyloid process, this process in rabbit is raised much above the planes of the molar table and has a prolonged aspect in a longitudinal plan. In front of the shallow mandibular notch, the coronoid process is short and blunt process situated in front of mandibular notch. In the rabbit mandible the alveoli for the canine teeth were absent resulting in a large diastema Mandibular foramen situated on the medial surface immediately behind the last molar. There is a large retroalveolr foramen. The female local rabbit showed significant greater measurement than the male.

New Pleistocene remains of megalonychid ground sloths (Xenarthra: Pilosa) from the intertropical Brazilian region

The Pleistocene fossil slothAustralonyx aquaeDe Iuliis, Cartelle, and Pujos, 2009 (Mammalia, Xenarthra, Megalonychidae) was described from the intertropical region of Brazil. However, its mandible was not known and only cursory descriptions of the ear ossicles were included. The mandible was subsequently recognized among the remains originally collected from the type locality, and belongs to the holotype individual. As a particularly important skeletal element for specific recognition, it requires description to complement our understanding of this species. The ossicles, usually poorly represented in the fossil record, require further description to allow differentiation from those of other sloths. Comparisons of the mandible and ossicles are conducted with homologous elements of the contemporaneous and sympatricAhytherium aureumCartelle, De Iuliis, and Pujos, 2008, the only other megalonychid sloth known from intertropical Brazil, and reinforce the distinction between these two species detailed in their initial descriptions. Comparisons with other sloths (e.g.,Acratocnus,Megalonyx,Neocnus) also reveal differences withAu.aquaein such features as form and size of the caniniform tooth, angular process, and mandibular condyle. Differences among the malleus and incus ofAu.aquaeand several species of other sloth clades reveal clade level distinctions among Megatheriidae, Nothrotheriidae, and Megalonychidae. A well-preserved skull from the Brazilian state of Rondônia is noted as probably belonging toAu.aquae. This skull cannot be assigned formally to this species because it is not deposited in a recognized institution, but it does extend considerably the known range of the species.

Morphological characterization and sex-related differences of the mandible of the armadillos Chaetophractus vellerosus and Zaedyus pichiy (Xenarthra, Dasypodidae), with consideration of dietary aspects

The morphological characteristics of the mandible of adult Chaetophractus vellerosus (Gray, 1865) and Zaedyus pichiy (Desmarest, 1804) were studied to establish its generalized design and to identify inter- and intra- (sexual) specific differences. Morphological descriptions were complemented with the application of univariate and multivariate (analysis of correlation matrices, PCA, discriminant analysis) techniques. The mandible of both species is very similar, and is characterized by elevated condyle, well developed angular process, distinct coronoid process, tooth row which extends to the rear end of the angle between body and ramus, and unfused but firm symphysis. Although both armadillos are omnivorous, a more slender configuration of the jaw in Z. pichiy could be indicative of a better adaptation of its masticatory apparatus to insectivory. The PCA showed an almost total segregation of both species on PC1 (47.7% of the total variance), with C. vellerosus being associated to mandibles taller and with wider body and ramus. Zaedyus pichiy was characterized by heavy loadings of length parameters on PC2 (22.6% of the variance). A small degree of sexual dimorphism was found, with size-based differences in C. vellerosus (larger mandibles in females) and shape-based differences in Z. pichiy (taller mandibles in males, longer ones in females). Correlations between variables were higher in males of both species, indicating a more stable shape of the mandible than in females. The selected parameters to discriminate sexes were the body length of the mandible in C. vellerosus (correct classification: ca. 86% in males, 81% in females), and the height of the mandible at the level of the last tooth in Z. pichiy (near 85% of right assignment in both sexes). The inclusion of a new variable (body length) in the latter species improved the classification of the females to 100%. Teeth are typically 10 in C. vellerosus and 9 in Z. pichiy, but aberrancies in this basic number, such as unilateral or bilateral extra or fewer teeth, are common.

Bilateral Extracapsular Soft-Tissue Ossification Affecting Range of TMJ Motion in an Airedale Terrier

A 3 mo old female Airedale terrier presented with decreased range of motion of the temporomandibular joint (TMJ), which was first recognized at weaning. Computed tomography (CT) revealed abnormal, bilateral ossification of the soft tissues extending from the region of the tympanic bullae to the medial aspect of the angular process of each mandible. Those ossified structures most closely approximated the location of the lateral pterygoid muscles. The ossified structures were present at presentation and initially manifested as complete ossification on the right side. The condition progressed to complete bilateral ossification by 3 yr of age. The mandibular condyles associated with the temporomandibular joints were malformed. The patient had severe mandibular distoclusion with deviation of the mandible to the left. The left mandibular cheek teeth were positioned in a caudal cross bite. A single treatment of manual stretching and breakdown of the ossified muscle of mastication by placement of tongue depressors within the oral cavity resulted in no increase in TMJ range of motion as measured by the incisal opening. This is the first reported case of spontaneous false ankylosis of the TMJ in an Airedale terrier.