Gross morphological and morphometric study of the upper respiratory system of the African giant rat (Cricetomys gambianus, Waterhouse 1840).

The nose is a structurally and functionally complex organ in the upper respiratory tract. It not only serves as the principal organ for the sense of smell, but also functions to efficiently filter, warm, and humidify inhaled air before the air enters the more delicate distal tracheobronchial airways and alveolar parenchyma of the lungs. Despite the volume of published studies on the biology of rodents, there is no information on the gross upper respiratory morphology of the African giant rat (AGR) in the available literature. Hence, this study aimed to examine the anatomy of the turbinates, their meatuses, and the morphometry of the nasal cavity. The following were found and reported in this study: (a) There were three nasal conchae in AGR: the nasoturbinate, which was the largest; the ethmoturbinate, which was composed of one well-developed ectoturbinate and three well-developed endoturbinates; and the maxilloturbinate, which was fusiform, short, and branched. (b) Three major meatuses were observed: the dorsal nasal meatus, which was the longest and widest; the middle nasal meatus, which was without limbs but had a deep oval caudal recess; and the ventral nasal meatus, which directly continued caudally into the nasopharyngeal meatus. (c) Four ethmoturbinates with four slit-like meatuses were observed, each with dorsal and ventral limbs; the first contacted the middle nasal meatus but not the nasopharyngeal meatus. (d) There were three paranasal sinuses: one sphenoid, two frontal, and two palatine sinuses. The data obtained are relevant to pathologists and eco-morphologists, considering the burrowing habitat and behaviors of AGR, and provide baseline data for more investigative studies.

Morphological and morphometric studies on the axial skeleton of the sitatunga (Tragelaphus spekii gratus).

BACKGROUND: Anatomical features of the skeleton of wild animals contribute largely to their adaptation. A dearth of information on the skeletal anatomy of the sitatunga (Tragelaphus spekii gratus) necessitated this study. Two adult sitatunga carcasses weighing 54 kg and 57 kg were obtained after post-mortem examination. Bone preparation was achieved through cold water maceration protocol. RESULT: The tympanic bulla was elongated and massive, resulting in the rudimentary appearance of the styloid and muscular processes of the temporal bone. The lacrimal bone had a somewhat triangular presentation with the lacrimal foramen on the caudal border of the facial surface while its dorsal border formed the lateral margin of the frontal sinus. There was no observable lacrimal fossa on this facial surface of the lacrimal bone. The facial tubercle was absent. The vertebral column formula was C7 T13 L6 S4 C10-14, and the atlas dorsal median tubercle was smooth, devoid of ridges. The spinous process of the axis extended the entire arch length to hang little above the odontoid process. The thoracic spinous processes were oriented dorso-caudally from T1 to T11; spinous process of T12 was vertical, while that of T13 was oriented dorso-cranially. The length of the transverse process of L1 and L6 were the same, and smaller than the length of those of L2-L5. There was incomplete fusion of sacral spinous processes. Three dorsal and ventral sacral foramina were identified laterally on each side of the vertebrae. The ribs were 26 in number (13 pairs). The sternum was comprised of 5 sternabrae separated by intersternal cartilage. The average number of bones of the axial skeleton was 75. Morphometric in formation included the length of skull, mandible and ribs; body length of vertebrae and spinous process length and height of the vertebrae. CONCLUSION: This study recorded anatomical features and biometric information on axial skeletal bones of the Sitatunga (Tragelaphus spekii gratus) thereby providing baseline data for future biomedical, archaeological and comparative skeletal anatomical studies.