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Sarcocysts were found during the examination of muscle samples from four different Equidae from the zoo in Berlin-Friedrichsfelde (Przewalski’s feral horse, Chapman’s plain zebra, kulan, kiang), a Damara plain zebra from the Cologne zoo, and a domestic horse from Mongolia. Light and electron microscopic features of these sarcocysts correspond largely. The cyst walls of all the six forms represent type 11 from the classification system by Dubey et al. 1989. On this ultrastructural basis, one could postulate the existence of two or only one species, depending on the emphasis that is laid on the presence or absence of large osmiophilic granules within the cyst wall protrusions. Equus caballus przewalskii, E. burchellii chapmani, E. burchellii antiquorum, E. kiang holdereri, and E. onager kulan have not been previously described as hosts for sarcocysts belonging to ТЕМ wall type 11. In addition to the ТЕМ wall type 11 forms, a type 7 form is known in horses. It is not possible for the time being to list Sarcocystis asinus Gadaev, 1978 as a synonym of a Sarcocystis species found in equids. Hence S. asinus is declared a species inquirenda.
The caudal intercarotid artery was investigated in 6 species of Equidae family and in lowland tapir of Tapiridae family. It was found that this artery connects bilateral intracranial segments of the internal carotid artery. It is located in the cavernous and intercavernous sinuses, caudal to the hypophysis. This artery being constant vessel in horse, is also permanent vessel in other species of Equidae family. It is homologous with anastomising vessel in fishes, amphibia, reptiles and birds.
The long bones (humerus, radius, metacarpus, femur, tibia, metatarsus) of 51 extant bovid and 7 equid specimens were measured in order to test the hypothesis that they show adaptations to different habitats. We performed factor analyses (FAs) with principal component extraction method and plotted the extracted factors (Fs) in simple scatterplots. The preferred habitats (grassland, forest, mountainous regions) were labeled in the plots, and our results show three clearly separated clusters for F2 vs. F3. According to our interpretation, F1 reflects the body size of the specimens while F2 is most probably reflecting cursorial adaptations. F3 is largely affected by dimensional bone characteristics adapted to maneuver in the environment, and therefore, F3 is somehow linked to habitat. The investigated equids are plotting within the cluster of bovids preferring grassland habitats, which is surprising because of different constructions of the metapodials in perissodactyls and ruminants. Performed linear discriminant analyses (LDAs) are supporting our FA results. This approach combines biometrics with statistics and presents a tool, which easily can be applied helping to identify the paleo-habitat or the paleo-ecology of extinct bovids with implications on fossil localities.
Preliminary observations of the behaviour in two wild equids : Przewalski horse (Equus ferus przewalskii) and Hartmann`s zebra (Equus zebra hartmannae) kept in socially changed groups at Warsaw Zoo Investigations were carried out at Warsaw Zoo to examine general behaviour in two wild equids after social changes. This changes were caused by management procedures. Three Hartmann`s zebra and four Przewalski horses were observed for 117 hours throughout the whole year. Three methods of sampling were used: ad libitum, scan and focal. Abnormal behaviour in these wild equids was not found. There were several significant differences in frequency of behaviour between Przewalski horse and Hartmann`s zebra . In both species coordination of behaviour also occured. Social interaction frequency was very low and gave little support for the speculation about social structures in these groups.
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