Examined bones were obtained from eight adult African giant rats, Cricetomys gambianus Waterhouse. Animals used had an average body mass of 730.00 ± 41.91 gm and body length of 67.20 ± 0.05 cm. The vertebral formula was found to be C7, T13, L6, S4, Ca31–36. The lowest and highest points of the cervicothoracic curvature were at C5 and T2, respectively. The spinous process of the axis was the largest in the cervical group while others were sharp and pointed. The greatest diameter of the vertebral canal was at the atlas (0.8 cm) and the lowest at the caudal sacral bones (2 mm). The diameter of the vertebral foramen was the largest at C1 and the smallest at the S4; the foramina were negligibly indistinct caudal to the sacral vertebrae. There were 13 pairs of ribs. The first seven pairs were sternal, and six pairs were asternal of which the last 2-3 pairs were floating ribs. The sternum was composed of deltoid-shaped manubrium sterni, four sternebrae, and a slender processus xiphoideus. No sex-related differences were observed. The vertebral column is adapted for strong muscular attachment and actions helping the rodent suited for speed, agility, dexterity, and strength which might enable it to overpower prey and escape predation.

The olfactory system typically consists of two parallel systems: the main olfactory system and the accessory olfactory system. The main olfactory bulb (MOB) acts as the initial processing site for volatile chemical stimuli and receives input from the olfactory receptor cells located in the olfactory epithelium. The African giant rat is reputed to have abilities to detect landmines and tuberculosis samples by sniffing. This study therefore is a preliminary study on the histological and immunohistochemical anatomy of the olfactory bulb of the African giant rat (Cricetomys gambianus, Waterhouse). Nissl and Klüver-Barrera histological staining of the olfactory bulb revealed a cytoarchitecture typical of most mammals with 6 cell layers, and 1-2-layered glomeruli measuring approximately 150 μm each in diameter. Immunohistochemical staining with glial fibrillary acidic protein (GFAP) and 2',3'-cyclic nucleotide 3-phosphodiesterase (CNPase) revealed cellular conformations relative to most mammals. GFAP immunohistochemistry also revealed cell bodies and processes within the periglomerular area which may potentiate signaling from the olfactory receptor cells, while CNPase largely showed soma and evidence of myelin sheath deposition, confirming myelination at different layers of the bulb. Neurogenesis was examined using the neurogenic markers doublecortin (DCX) and Ki-67. Migration of newly generated cells was observed in all layers of the MOB with DCX and in most layers with Ki-67. The anatomy of the olfactory bulb is described as relatively large in the African giant rat, having a neuroarchitecture similar to most rodents.

Ten adult African giant rats (AGR), 5 males and 5 females, were used to determine the regional anatomy of their oral cavity. Body measurements were recorded. The oral cavity was accessed by disarticulating the temporo-mandibular joint and the gross morphology of the lips, palate, cheek pouch, teeth, tongue and major salivary glands were studied. Morphometric parameters of the cheek pouch, tongue and major glands were also determined. Histological features of the tongue were demonstrated after haematoxylin and eosin staining. The upper lip revealed a philtrum extending from the median septum of the nostrils and terminating at the oral fissure in a divergent triangle to expose the elongated incisors. The lower lip formed a smooth arch ventral to the upper lip. Average number of palatine ridges was 9. The tongue (mean weight of 3.80±0.08 g) appeared spatula shaped. Main papillae were filiform and fungiform, with scattered vallate papillae on histology. The mean pouch capacity of males and females was 27.46±0.41 mL and 27.18±0.49 mL respectively while the dentition of the AGR was noted as 2(I1/1 C0/0 P0/0 M3/3) and showed typical rodent features. The major salivary glands (parotid and mandibular) were well developed. This work reports baseline research data on the anatomy of the AGR's oral cavity and will have usefulness in determining the adaptive features in this rodent to its diet, habitat and lifestyle.