A morphometric study on skulls of Hasmer and Hasak sheep breeds / Un estudio morfométrico de cráneos de razas de ovejas Hasmer y Hasak

SUMMARY: The aim of the study was to investigate the head structures of two domestic sheep breeds (Hasak and Hasmer) in Turkey. Gender neutral eight adult Hasmer sheep of 45-66 kg and eight Hasak sheep breeds of 43-66 kg obtained from Bahri Dag˘das¸ International Agricultural Research Institute were used in this study. Measurements were made using digital caliper from 40 points on the skulls of both species. The skull of Hasmer sheep (265.56 ± 14.08) was longer than the skull of Hasak sheep (262.86 ± 9.65). However, the length of the arcus alveolaris maxillaris (77.01 ± 5.08), the length of the molar teeth (50.81 ± 1.22) and the length of the premolar teeth (26.16 ± 4.62) of Hasak sheep were compared to the Hasmer sheep (71.59, ± 5.25; 47.99 ± 3.64; 24.03 ± 3.76, respectively) was observed to be greater. According to these findings, although the skull length of Hasak sheep was shorter than that of Hasmer sheep and arcus alveolaris maxillaris in which molar and premolar teeth were placed was longer. In Hasmer sheep the values of greatest breadth of the foramen magnum, height of the foramen magnum (basion - opisthion), greatest neurocranium breadth-greatest breadth of the braincase (euryon - euryon) were higher than those of Hasak sheep. The difference between these values was also statistically significant (p <0.05). The lateral length of the premaxilla (nasointermaxillare- prosthion) parameter measured between these two species was statistically very important (p <0.01). In conclusion, in this study craniometric values depending on skull morphology of Hasmer and Hasak sheep which accepted as native breeds of Turkey were tried, to reveal similarities and differences with other sheep breeds in both amongst themselves.

El objetivo del estudio fue investigar las estructuras de la cabeza de dos razas de ovejas domésticas (Hasak y Hasmer) de Turquía. En este estudio se utilizaron ocho ovejas Hasmer adultas de género neutral de 45-66 kg y ocho ovejas de raza Hasak de 43-66 kg, obtenidas del Instituto Internacional de Investigación Agrícola Bahri Dagdas. Las mediciones en los cráneos de ambas especies se realiza-ron con caliper digital de 40 puntos. El cráneo de la oveja Hasmer (265,56 ± 14,08 mm) era más largo que el cráneo que el de la oveja Hasak (262,86 ± 9,65 mm). En las ovejas Hasak la longitud del arcus alveolaris maxillaris fue 77,01 ± 5,08 mm, la longitud de los dientes molares fue 50,81 ± 1,22 mm y la longitud de los dientes premolares fue de 26,16 ± 4,62 mm, en cambio en las ovejas Hasmer fue de 71,59 ± 5,25 mm; 47,99 ± 3,64 mm; 24,03 ± 3,76 mm, respectivamente. Según estos hallazgos, la longitud del cráneo de la oveja Hasak era más corta que la de la oveja Hasmer y el arcus alveolaris maxillaris en el que se colocaron los dientes molares y premolares era más largo. En ovinos Hasmer los valores de mayor amplitud del foramen magnum, altura del foramen magnum (basion - opisthion), mayor amplitud del neurocráneo-mayor amplitud de la caja craneana (euryon - euryon) fueron superiores a los de las ovejas Hasak. La diferencia entre estos valores también fue estadísticamente significativa (p <0,05). El parámetro de longitud lateral del premaxilar (nasointermaxillare-prosthion) medido entre estas dos especies fu estadísticamente significativo (p <0.01). En conclusión, los valores craneométricos en relación a la morfología del cráneo de las ovejas Hasmer y Hasak que se definieron como razas autóctonas de Turquía revelaron similitudes y diferencias con otras razas de ovejas.

Size and shape variability in the skull of Myotis nigricans (Schinz, 1821) (Chiroptera: Vespertilionidae) from two geographic areas in Brazil / Variação de tamanho e forma no crânio de Myotis nigricans (Schinz, 1821) (Chiroptera: Vespertilionidae) de duas áreas geográficas no Brasil

We present a quantitative analysis of sexual dimorphism and geographic variation in the skull of Myotis nigricans (Schinz, 1821) assessed by geometric morphometrics. Differences in size and shape of skulls were investigated using 30 landmarks plotted on two-dimensional images of lateral and ventral views. Results of geometric morphometrics revealed sexual dimorphism in the centroid size of the skull in both views. Females were larger than males. Nevertheless, there was no sexual dimorphism in skull shape of M. nigricans. Geographic variation was detected in size and shape of the skull. South Brazilian specimens were significantly larger than Ceará specimens only in the lateral view. Differences in skull shape were statistically significant in both views: specimens from South Brazil were brevirostri and presented a more expanded skull in the posterior region while Ceará specimens were longirostri and do not present any expansion in the brain case. Ecological factors for these phenomena are discussed in the text.

Uma análise quantitativa do dimorfismo sexual e da variação geográfica do crânio de Myotis nigricans (Schinz, 1821) é apresentada através da morfometria geométrica. Diferenças no tamanho e na forma do crânio foram avaliadas através de imagens bidimensionais das vistas lateral e ventral do crânio, onde foram estabelecidos 30 marcos anatômicos. Os resultados indicaram a existência de dimorfismo sexual no tamanho do centróide do crânio para ambas as vistas estudadas. As fêmeas foram maiores que os machos. Contudo, não foi detectado dimorfismo sexual na forma do crânio de M. nigricans. A variação geográfica esteve presente no tamanho e na forma do crânio. Espécimes do Sul do Brasil tiveram tamanho do centróide maior que os espécimes do Ceará apenas na vista lateral. Diferenças na forma do crânio foram estatisticamente significativas em ambas as vistas: os espécimes do Sul do Brasil apresentaram-se brevirostri e com grande expansão na região posterior do crânio, enquanto os espécimes do Ceará apresentaram crânios longirostri e sem expansão posterior da caixa craniana. São discutidos fatores ecológicos para estes fenômenos.

The correlation between anatomical measurement and CT measurement of the adult occipital thickness / 中华创伤骨科杂志

Objective To study the correlation between anatomical measurement and CT measurement of adult occipital thickness so as to provide anatomic evidence for the selection of screw length in occipital-cervical fusion. Methods The occipital thickness was measured on the occipital specimens of 10 normal adults in two ways: direct anatomic measurement and CT measurement. Measurements were made on the basis of the McRac' s line and according to a matrix of 66 points following a grid with one cm spacing. The results of both measurements were statistically analyzed using SPSS 10.0. Results The results of both measurements were highly correlated. The external occipital protuberance was the thickest while the region of cerebellar fossa was the thinnest. The regions two cm lateral to the midline between plane Five and plane Six, one cm lateral to the midline between plane Four and at plane Five, and median between plane Three and plane Four were found to have a thickness of more than eight mm. Conclusions The occipital thickness varies with individuals. CT measurement and direct anatomic measurement are highly correlated. Preoperative CT measurements can be reliable evidence for optimal screw placement before performing occipital-cervical fusions.